The Lady or the Tiger Essay Example for Free

The Lady or the Tiger Essay Long ago, in the very olden time, there lived a powerful king. Some of his ideas were progressive. But others caused people to suffer. One of the kings ideas was a public arena as an agent of poetic justice. Crime was punished, or innocence was decided, by the result of chance. When a person was accused of a crime, his future would be judged in the public arena. All the people would gather in this building. During ceremony the king sat high up on his ceremonial chair. He gave a sign. A door under him opened. The accused person stepped out into the arena. Directly opposite the king were two doors. They were side by side, exactly alike. The person on trial had to walk directly to these doors and open one of them. He could open whichever door he pleased. If the accused man opened one door, out came a hungry tiger, the fiercest in the land. The tiger immediately jumped on him and tore him to pieces as punishment for his guilt. The case of the suspect was thus decided. But, if the accused opened the other door, there came forth from it a woman, chosen especially for the person. To this lady he was immediately married, in honor of his innocence. It was not a problem that he might already have a wife and family, or that he might have chosen to marry another woman in the future. The king permitted nothing to interfere with his great method of punishment and reward. The king had a beautiful daughter who was like him in many ways. He loved her above all humanity. The princess secretly loved a young man who was the best-looking and bravest in the land. But he was a commoner, not part of an important family. One day, the king discovered the relationship between his daughter and the young man. The man was immediately put in prison. A day was set for his trial in the kings public arena. This, of course, was an especially important event. Never before had a common subject been brave enough to love the daughter of the king. The king knew that the young man would be punished, even if he opened the right door. And the king would take pleasure in watching the series of events, which would judge whether or not the man had done wrong in loving the princess. The day of the trial arrived. From far and near the people gathered in the arena and outside its walls. The king and his advisers were in their places, opposite the two oors. All was ready. The sign was given. The door under the king opened and the lover of the princess entered the arena. Tall, beautiful and fair, his appearance was met with a sound of approval and tension. Half the people had not known so perfect a young man lived among them. No wonder the princess loved him! What a terrible thing for him to be there! As the young man entered the public arena, he turned to bend to the king. But he did not at all think of the great ruler. The young mans eyes instead were fixed on the princess, who sat to the right of her father. From the day it was decided that the sentence of her lover should be decided in the arena, she had thought of nothing but this event. The princess had more power, influence and force of character than anyone who had ever before been interested in such a case. She had done what no other person had done. She had possessed herself of the secret of the doors. She knew behind which door stood the tiger, and behind which waited the lady. Gold, and the power of a womans will, had brought the secret to the princess. She also knew who the lady was. The lady was one of the loveliest in the kingdom. Now and then the princess had seen her looking at and talking to the young man. The princess hated the woman behind that silent door. She hated her with all the intensity of the blood passed to her through long lines of cruel ancestors. Her lover turned to look at the princess. His eye met hers as she sat there, paler and whiter than anyone in the large ocean of tense faces around her. He saw that she knew behind which door waited the tiger, and behind which stood the lady. He had expected her to know it. The only hope for the young man was based on the success of the princess in discovering this mystery. When he looked at her, he saw that she had been successful, as he knew she would succeed. Then his quick and tense look asked the question: Which? It was as clear to her as if he shouted it from where he stood. There was not time to be lost. The princess raised her hand, and made a short, quick movement toward the right. No one but her lover saw it. Every eye but his was fixed on the man in the arena. He turned, and with a firm and quick step he walked across the empty space. Every heart stopped beating. Every breath was held. Every eye was fixed upon that man. He went to the door on the right and opened it. Now, the point of the story is this: Did the tiger come out of that door, or did the lady? The more we think about this question, the harder it is to answer. It involves a study of the human heart. Think of it not as if the decision of the question depended upon yourself. But as if it depended upon that hot-blooded princess, her soul at a white heat under the fires of sadness and jealousy. She had lost him, but who should have him? How often, in her waking hours and in her dreams, had she started in wild terror, and covered her face with her hands? She thought of her lover opening the door on the other side of which waited the sharp teeth of the tiger! But how much oftener had she seen him open the other door? How had she ground her teeth, and torn her hair, when she had seen his happy face as he opened the door of the lady! How her soul had burned in pain when she had seen him run to meet that woman, with her look of victory. When she had seen the two of them get married. And when she had seen them walk away together upon their path of flowers, followed by the happy shouts of the crowd, in which her one sad cry was lost! Would it not be better for him to die quickly, and go to wait for her in that blessed place of the future? And yet, that tiger, those cries, that blood! Her decision had been shown quickly. But it had been made after days and nights of thought. She had known she would be asked. And she had decided what she would answer. And she had moved her hand to the right. Long ago, in the very olden time, there lived a powerful king. Some of his ideas were progressive. But others caused people to suffer. One of the kings ideas was a public arena as an agent of poetic justice. Crime was punished, or innocence was decided, by the result of chance. When a person was accused of a crime, his future would be judged in the public arena. All the people would gather in this building. During ceremony the king sat high up on his ceremonial chair. He gave a sign. A door under him opened. The accused person stepped out into the arena. Directly opposite the king were two doors. They were side by side, exactly alike. The person on trial had to walk directly to these doors and open one of them. He could open whichever door he pleased. If the accused man opened one door, out came a hungry tiger, the fiercest in the land. The tiger immediately jumped on him and tore him to pieces as punishment for his guilt. The case of the suspect was thus decided. But, if the accused opened the other door, there came forth from it a woman, chosen especially for the person. To this lady he was immediately married, in honor of his innocence. It was not a problem that he might already have a wife and family, or that he might have chosen to marry another woman in the future. The king permitted nothing to interfere with his great method of punishment and reward. The king had a beautiful daughter who was like him in many ways. He loved her above all humanity. The princess secretly loved a young man who was the best-looking and bravest in the land. But he was a commoner, not part of an important family. One day, the king discovered the relationship between his daughter and the young man. The man was immediately put in prison. A day was set for his trial in the kings public arena. This, of course, was an especially important event. Never before had a common subject been brave enough to love the daughter of the king. The king knew that the young man would be punished, even if he opened the right door. And the king would take pleasure in watching the series of events, which would judge whether or not the man had done wrong in loving the princess. The day of the trial arrived. From far and near the people gathered in the arena and outside its walls. The king and his advisers were in their places, opposite the two doors. All was ready. The sign was given. The door under the king opened and the lover of the princess entered the arena. Tall, beautiful and fair, his appearance was met with a sound of approval and tension. Half the people had not known so perfect a young man lived among them. No wonder the princess loved him! What a terrible thing for him to be there! As the young man entered the public arena, he turned to bend to the king. But he did not at all think of the great ruler. The young mans eyes instead were fixed on the princess, who sat to the right of her father. From the day it was decided that the sentence of her lover should be decided in the arena, she had thought of nothing but this event. The princess had more power, influence and force of character than anyone who had ever before been interested in such a case. She had done what no other person had done. She had possessed herself of the secret of the doors. She knew behind which door stood the tiger, and behind which waited the lady. Gold, and the power of a womans will, had brought the secret to the princess. She also knew who the lady was. The lady was one of the loveliest in the kingdom. Now and then the princess had seen her looking at and talking to the young man. The princess hated the woman behind that silent door. She hated her with all the intensity of the blood passed to her through long lines of cruel ancestors. Her lover turned to look at the princess. His eye met hers as she sat there, paler and whiter than anyone in the large ocean of tense faces around her. He saw that she knew behind which door waited the tiger, and behind which stood the lady. He had expected her to know it. The only hope for the young man was based on the success of the princess in discovering this mystery. When he looked at her, he saw that she had been successful, as he knew she would succeed. Then his quick and tense look asked the question: Which? It was as clear to her as if he shouted it from where he stood. There was not time to be lost. The princess raised her hand, and made a short, quick movement toward the right. No one but her lover saw it. Every eye but his was fixed on the man in the arena. He turned, and with a firm and quick step he walked across the empty space. Every heart stopped beating. Every breath was held. Every eye was fixed upon that man. He went to the door on the right and opened it. Now, the point of the story is this: Did the tiger come out of that door, or did the lady? The more we think about this question, the harder it is to answer. It involves a study of the human heart. Think of it not as if the decision of the question depended upon yourself. But as if it depended upon that hot-blooded princess, her soul at a white heat under the fires of sadness and jealousy. She had lost him, but who should have him? How often, in her waking hours and in her dreams, had she started in wild terror, and covered her face with her hands? She thought of her lover opening the door on the other side of which waited the sharp teeth of the tiger! But how much oftener had she seen him open the other door? How had she ground her teeth, and torn her hair, when she had seen his happy face as he opened the door of the lady! How her soul had burned in pain when she had seen him run to meet that woman, with her look of victory. When she had seen the two of them get married. And when she had seen them walk away together upon their path of flowers, followed by the happy shouts of the crowd, in which her one sad cry was lost! Would it not be better for him to die quickly, and go to wait for her in that blessed place of the future? And yet, that tiger, those cries, that blood! Her decision had been shown quickly. But it had been made after days and nights of thought. She had known she would be asked. And she had decided what she would answer. And she had moved her hand to the right.

Anti Jerk Control Of Hybrid Electric Vehicles Engineering Essay

Anti Jerk Control Of Hybrid Electric Vehicles Engineering Essay This interim report consists of three chapters explaining the initial study and research into anti jerk control of hybrid electric vehicles. This project aims at electrification of anti-jerk control in hybrid vehicles by using the hybrid vehicle electric motor to damp these oscillations and to analyze its effect on fuel consumption, comfort and sportiness of the vehicle and then to compare the results with fuelling only method. This project will also include studying the impact of passive damping with DMF in these vehicles. As a part of this project, a model of a hybrid diesel engine driveline with DMF will be developed using Simulation X and an active feedback control for an electric motor will be designed to permit active damping of these oscillations. The results obtained from simulating the drivelines modeled using Simulation X will be observed for driveline vibrations with respect to the frequency range and also the range in which the jerking frequencies affect the passengers inside the vehicle so as to concentrate on it specifically leading to maximum reduction in jerking of driveline. The models so developed will then subjected to design modifications and investigation in accordance with the control strategies developed and affect of the same will be observed on all the drive train models with level of jerk control achieved. Finally Suggestions will be made on effect of electric motor on hybrid drive train in damping the driveline oscillations, fuel consumption and sportiness of the vehicle also comparing it with the conventional drive train models. Introduction In the age of technology where everyone is concentrating on improving the products by bringing in sophisticated technologies from cars to airplanes, we as human beings neglected the environment factor over the years. 20th century was called an industrial age and much technological advancement have been made in this era which revolutionized the whole world. One of the industries which is closely related to connect our daily life are automobiles. Automobiles have grown rapidly over the years with stiff competition among automotive manufacturers across the world. As the time passed by people become more demanding with their interests widening the automotive market and also the fact that automotive majors started delivering those demands. These technological improvements along with human comfort factors all of us forgot about the effect on environment. The number of vehicles on roads grew exponentially and consumption figures of petrol and diesel across the world increased drastically sending out alarm bells to search for alternate fuel technologies as the conventional petrol diesel were not only running out from their existence but also affecting the environment leading to considerable amount of CO2 emissions and further contributing to global warming. This future problem opened up opportunities for research in alternative fuel technologies leading to the development of Hybrid vehicles, Fuel cell technologies Hydrogen fuelled cars. Few of the alternate fuel vehicles are Toyota Prius hybrid, Honda Civic hybrid, Honda Insight etc which have received good response in the market in terms of performance as well as in reducing CO2 emissions and have successfully proved their presence in the market with their selling volumes and fuel savings. On a smaller level, these developments lead to further research in areas like DC/AC motors, fuel cells, battery pack technology, advanced controller design, power optimization and new concepts which can be used as alternate fuels. Problem Definition Commonly in every engine driven system issue of noise, vibration and harshness (NVH) comes along with it. Automotive manufacturers have always tried to maintain healthy comfort to performance ratio so as to attain maximum customer satisfaction. With respect to comfort of driving, the manufacturers main aims are to provide vibration free driving pleasure as much as possible and the same applied to hybrid electric vehicles. One such area of concern in drive line jerking which affects the overall drivability. Jerking is a kind of driveline oscillations which occurs due to excitation caused by sudden or huge variation in engine torque or driveline load. These excitations cause because of torsional vibration of drive train at high engine torques leading to unwanted longitudinal oscillations of passenger compartment which reduces the riding comfort and drivability. These oscillations have tendency to occur at low engine speeds which are experienced as unpleasant jerking effect by the drive r. Due to the fact diesel engines produce high torque at low engine speeds, makes these engines more prone to this problem. The area of concentration under this case is vibration frequencies ranging between 2- 10 Hz as human body is sensitive towards this frequency range causing unpleasant driving experience. These driveline oscillations majorly occur during tip in and tip out conditions. In conventional diesel engine vehicles methods like active control of fuel injection into engine and passive element such as dual mass flywheel are used to permit feed forward active as well as passive damping of these unpleasant oscillations in idle, tip-in/tip out and coast conditions. To achieve minimal amount of driveline oscillations, vehicle manufacturers have to compromise between comfort and performance of the vehicle. In diesel hybrids, the jerking can be controlled by varying fuel injection and electric motor torque control and also passively by an additional dual mass flywheel (DMF). Aims Objectives The aims and objectives of this project are: To develop a model with three different configurations of powertrain using Simulation X those are: Conventional diesel engine, Conventional diesel engine with DMF and finally hybrid power train with DMF. To study the effects of jerk in each individual power train configuration before developing the control strategy for anti jerk control. To electrify the anti jerk control in hybrid vehicles by using Crankshaft integrated stator/generator to damp the oscillations. To analyze the effect on fuel consumption, comfort and sportiness of the vehicle. To compare the results with conventional fuel control method. Literature Review Hybrid Electric Vehicles Hybrid Electric Vehicle is the one which uses two or more sources of energy to propel the vehicle which consists of an internal combustion engine and electric motor power by batteries. Hybrid vehicles are of various types such as series hybrid, parallel hybrid and combination of series parallel and based on their hybridization factor they are categorized into micro, mild and full hybrids. Figure 1, below shows the typical power split type power train. Generally, hybrid power trains are costly to build due to its complexity but the costs are paid off against the running costs due to improved fuel efficiency. Regenerative braking plays an important role in conserving energy by charging the battery pack. Figure : Showing a Power Split Hybrid Powertrain Types of Hybrid vehicles based on drive train structure Parallel Hybrid In parallel hybrid vehicles, there are two parallel ways for transmitting power to the wheels of the vehicle; those are by engine and by electric drive, as shown in below figure 2. The transmission is coupled with the motor/generator and the engine, allowing either, or both, to power the wheels. Control architecture of parallel hybrid vehicles is more complex compared to a series hybrid due to the requirement of efficient coupling of the motor/generator and engine so as to maintain optimum drivability and performance. Figure : Parallel Hybrid Powertrain Operating modes available in parallel hybrid vehicles are: Engine only traction Electric only traction Hybrid traction Regenerative braking Series Hybrid In series hybrid there is only one way for transmitting power to the wheels of the vehicle, but consists two energy sources. As shown in figure 3, the conventional engine is coupled to a generator for charging the battery pack which provides electrical energy to a motor/generator to power the wheels via transmission. The motor/generator can also be used for recharging the battery during braking and deceleration. Figure : Series Hybrid Power train Operating modes available in series hybrid vehicles are: Electric only traction Electric traction battery charging Battery charging and no traction Regenerative braking Series-Parallel (combined) Hybrid electric vehicles A Series-Parallel (combined) hybrid vehicle has both the aspects Series and Parallel energy transfer paths. As shown in figure 5, a system consisting of motors and/or generators consisting of a gearing or power split device allows the engine to recharge the battery. Changes in this power train configuration can range from simple to very complex type depending on the number of motors /generators and their working terminology. These configurations can be called as Complex hybrids (such as the Toyota Prius and Ford Escape Hybrids), Split-Parallel hybrids, or Power-Split hybrids. Figure : Series-Parallel (Combined) Hybrid Power train Driveline Jerking Driveline jerking also called as driveline oscillations can occur due to many different factors such as load changes, gear shifting and also the condition of the road. In recent times, direct injection diesel engines with extensive refinement of components and significant weight reduction in driveline lead to the problem of driveline jerking. Also with advancement in diesel engine technology over the years, output torque of these diesel engines has risen tremendously for passenger cars effecting the comfort and drivability. The problem with high engine torque is, it causes torsion of driveline due to the gear ratios of the final drive causing the torsion at drive shafts which in turn causes whole power train to oscillate with combined effect of vehicle jerking. Figure 5, shown below show the measurements on a test car caused by tip in behavior in which driver suddenly steps on the throttle combined with high torque gradient and tip out condition, the back out maneuver. Figure : Engine torque and engine speed for tip in and tip out maneuvers. Though the oscillations caused by engine speed are somewhat absorbed by engine mounts but the oscillations due to wheel speed is responsible for horizontal vibrations of the vehicles longitudinal acceleration affecting the performance of the vehicle which is experienced directly by passengers. To restrain these oscillations affecting the comfort and drivabilityfor the passengers, damping of these driveline oscillations is necessary which is referred to as Anti Jerk Control. The oscillations leading to power train jerking in conventional power train can be categorized by the Eigen frequencies of following driveline components: Torsion of shafts causes pitching and jerking due to suspension system, mass of the vehicle and damping. The range of frequency for this cause lies between 2 5 Hz. Also, we know that the natural frequency of the vehicle with respect to pitch motion is lies between 1 2.5 Hz. The frequency of oscillations caused by engine movement and mounts lies in the range of 15 200 Hz. The vibration due to gearbox assembly lies in the frequency range of 50-80 Hz. There are oscillation depending upon the type of engine, no. of cylinders, engine speed and also the combustion process shown in below figure Table : showcasing different engine types and their Eigen frequencies Engine Type Multiples of Eigen Frequency 4-Cylinder ,R4, 4-Stroke 2,4,6,8,10 6-Cylinder,R4, 4-stroke 3,6,9 6-Cylinder,V60,4-Stroke 1,5, 3, 4,5, 6, 7,5, 9 6-Cylinder,V90,4-Stroke 1,5, 3, 4,5, 7,5, 9 12-Cylinder, V60, 4-Stroke 6,12 From the above categorization of the components and their respective Eigen frequencies, the main aim is to narrow down on the components leading to vibrations which are felt by passengers majorly and to minimize the level of vibrations by designing model based predictive control strategy while retaining the performance of the vehicle as much as possible. Hybrid Vehicle Design The power train which has been considered for testing the jerking behavior and the anti jerk control strategy to be designed is shown in the below figure 6. This power train is one of the possible hybrid vehicle architecture consisting of I.C engine, CISG (Crankshaft Integrated Starter/ Generator), Dual Mass Flywheel (DMF), Clutch, Gearbox assembly , High voltage battery pack and power electronics. Figure : Hybrid Vehicle architecture In operation, at lower rpm the vehicle acts as pure electric vehicle powered by the on board battery pack and at higher rpm, both electric drive and I.C engine together produce required power by the vehicle. The percentage of power transmission sharing to propel the vehicle plays an important role in determining fuel efficiency. Design Considerations The components and factors which play important role in hybrid electric vehicle design shown in figure 6 are: Engine design and selection: The I.C engine as in conventional power train plays an important role in hybrid vehicles. Generally, engines designed for hybrid vehicles are smaller in size compared to conventional vehicles. Though the design selection of the engine is completely based on the power requirements of the vehicle. Crankshaft integrated starter/generator (CISG): The starter/generator is device which is controlled electronically. It combines both the functions of a conventional starter and generator into a one single unit. The motive of single CISG unit is replacing the starter as a single entity which is passive in nature; need to replace the old fashioned belt and pulley type connection between the alternator the engine. Also to replace the modern day rotor wound alternators with slip rings and brushes. The integrated starter/generator works as a bi-directional device which converts electrical energy to mechanical work and vice versa. As a electric motor, it assists in starting the I.C engine without any noise and also much quicker than conventional starter. As a generator it produces power required for electrical components of the vehicle and is also used to charge the batteries. Commonly integrated starter/generator is placed between engine and gearbox assembly. The main operating features of ISG are it enables stat/stop, onboard power generation and acts as power assist when required. Figure : Integrated Starter / Generator. Dual Mass Flywheel (DMF): Dual mass flywheel consists of two flywheels connected by long arc travel springs located between I.C engine and clutch or transmission. The first DMF was introduced for the automotive industry in 1985. At that time non lubricated dampers were used consisting of heavy springs which were problematic. Then there was breakthrough in the DMF technology and arc spring type dampers was introduced in 1989 solving almost all the problems which were caused by DMF earlier. Due to the high cost of this product not everyone was interested but was used in large vehicles. Though DMF is a passive driveline element, it has been proven that DMF reduces torsional vibrations to certain extent and plays an important role in anti jerk control of hybrid vehicles also. The operating performance of DMF can be characterized by the spring rate and its damping characteristics. The dual mass flywheel consists of following important characteristics: Primary and secondary inertias. The torsion damper rate. And the damping characteristic. Advantages of using DMF in conventional power train are: Segregation of torsional vibrations: we know that, torsional vibrations are caused by torque fluctuations. A vehicle is a kind of vibrating system with all the components like engine, transmission, drive shafts etc all contributing to the cause. Below figure 8, shows the simple driveline model so as to observe vibration behaviour. In this case engine and transmission are supposed as rotating inertia connected by springs. The spring C2 represents the spring damper characteristics and spring C3 showing the stiffness of the drive train. Figure : Drive train with vibration modes. Figure 9 shown below depicts the fluctuations in vehicle speed and in this case damped resonance occurs at around 1700 rpm. The main aim of DMF is to sideline the vibrations occurring from the engine as far as possible from the rest of the driveline components. Also the figure compares the difference between the extents of vibrations in a conventional drive train compared to one fitted with dual mass flywheel. Dual mass flywheel efficiently reduces the engine vibrations and reduces gear rattle, helps in saving the fuel consumption and also improves driving comfort. Figure : Comparison of vibration damping in a conventional drive train to the one with DMF Transmission assistance: As DMF is said to reduce the engine vibrations, it has positive effect on the transmission system as the stress induced will be significantly less compared to a compared drive line increasing the transmission efficiency and cycle life. Crank shaft assistance: In a conventional power train, we know that flywheel and clutch are connected to engine crankshaft rigidly and due to the inertia of the flywheel high reaction forces are developed on the crankshaft. But in case of DMF, the secondary flywheel can be neglected for bending load case as it connected loosely to the primary flywheel by torsional damper and roller bearings which practically dont allow high transferable reactive forces. The primary flywheel is significantly lighter in weight, more elastic in nature compared to conventional flywheel. Battery pack design and selection: The main criteria in battery design and selection depend upon the capacity, the output characteristics based on type of battery pack to be used, cycle life, cost, scope of reusability and whether recyclable on not. The size and weight of the battery pack depends on the capacity requirement. If capacity is high, more will be size and weight of the battery pack. In fact, battery pack design plays a very important role as the performance of the vehicle is dependent on the overall weight of the vehicle. In case battery pack is heavier, this would have direct impact on the power consumed to propel the vehicle which is set to rise with increase in battery weight and will also reduce the operating range of the vehicle. Figure : Typical Battery pack arrangement Electric Motor: Generally AC, DC and PMDC electric motors are used in hybrid vehicle depending upon the requirement and usage. In automotive industry, certain motor specifications are not acceptable due to their inability to meet the specific requirements such as power rating at peak load conditions, continuous power supply, volumetric power density, cost, efficiency, weight, lifetime, level of protection against water and dust. Gear box assembly: In hybrid vehicles, mostly a power splitter device is used which is consists of planetary gear set allowing power flow from two power generating sources to propel the vehicle. The I.C engine is generally connected to Sun gear while electric motor is connected to the planet gear. Clutch: It is found in every vehicle with manual gearbox. Though the use of clutch varies from one hybrid drive train to another depending the gearbox being used as most of the hybrid power trains use automatic transmission which dont require clutch. The main purpose of clutch is to assist the vehicle starting off from stand still position as it compensates for the speed difference between engine and the driveline and slips on to synchronize both. Clutch also used to engage and disengages engine from the transmission while gear shifting takes place. Modelling Approach Procedure of work Power train jerking in hybrid vehicles is majorly due to engine electric motor torque changes during tip in and tips out operations. For investigating the problem of jerking for a hybrid vehicle, certain steps have been laid out for modeling the power train in five different steps which are in below figure 9 to observe and analyze each case individually with root cause: Figure : Modelling Procedure Basic Driveline Equations Engine: The engine output torque is expressed by the driving torque (Te) generated from combustion , friction torque (Tfric,e) and the external load from clutch (Tc) .By Newtons second law of motion, we can achieve the following model: Where Je is the mass of inertia of the engine, is the crank angular acceleration. Clutch: Generally a friction type clutch is installed in vehicles with manual transmission connecting to the engine flywheel and input shaft of the transmission. During clutch engagement if we assume no internal friction, Tc = Tt can be obtained. Then the torque transmitted is function of angular difference (ÃŽÂ ±cs ÃŽÂ ±c) and angular velocity difference ( ) resulting in: Figure : vehicle driveline with corresponding angle and torque labels. Transmission: A transmission consists of a gear set each with a different operating ratio it leading to relation between input and output torque Where Tp is the transmission output and Tfric is the internal friction torque of the transmission. Propeller shaft: The shaft which connects the transmissions output to the final drive unit in which no friction is assumed which gives us Tp = Tf , resulting in model for torque input to final drive Final Drive: final drive can be considered as a final ratio if as for the transmission leading to input and output torque relation Drive Shafts: The shafts which connect wheels to the final drive are called drive shafts. It can be assumed that both the wheels are rotating at same speed ( ). Ignoring the vehicle dynamics, the wheel speed shall be equal to speed of vehicle bodys centre of gravity. Therefore, drive shafts can be modelled as one shaft. Wheels: The forces acting on a vehicle with mass (m) and velocity (v) the longitudinal forces (FL)acting on the vehicle gives Rolling resistance (Rr) = f*m*g and Aerodynamic drag (Ra) =1/2*Af*Cd*à Ã‚ *V2. Where, m=mass of the vehicle, g=gravity constant, f=0.015(co-efficient of rolling resistance), Rr=rolling resistance, Ra=aerodynamic drag, Af=cross sectional area, Cd=coefficient of drag, density (à Ã‚ ), V=velocity. The drive line model can be expressed as a system consisting of rotating lumped inertias, compliances, damping losses, input torque and loads acting due to environmental resistive forces. A simple 2 degree of freedom model (fig 10) is sufficient to show the first torsional mode of vibrations which lead to jerking of vehicle. Figure : Free body diagram of a conventional driveline Where, Teng = engine torque, road load = Tload , e = engine speed, v = vehicle speed, Je = mass moment of inertia, be = viscous friction, r = final drive ratio, Ks CS = drive shafts flexibility, Cw = damper, vehicle inertia = Jv. Hybrid Power train Model As discussed earlier in report, the hybrid power train consists of additional components compared to conventional type which include electric motor, batteries, power electronics which form together the electric drive unit of the vehicle. Engine: Engine in hybrid power train plays a very important role in terms of fuel savings and vehicle assist. An engine model to be used for hybrid power train must be considered for following issues: The engine model must produce desired torque output irrespective of operating conditions. The engines dynamic behaviour leading to torque fluctuations generates drive line vibrations which in turn affects the driver comfort. As engine is not quick enough to respond to control actions implemented externally, the response delay can have significant affect on the vehicles performance. Engine can be modeled in many different ways depending upon the level of complexity required and the availability of parameters which can later be used for validating the inputs. The basic equation of engine model has been already discussed earlier which can be applied for the hybrid power train model also. Electric Motor/ Controller: The electric traction motor and controller consume the power from the onboard energy storage device like battery to provide the power source so as to generate the required torque for vehicle propulsion. The electric motor can also be used as starter/alternator or as a generator to recover energy during braking which can be used to charge batteries. The traction motor model can be described by following equations: Where idr , iqr are d,q axis rotor current respectively; ids ,iqs are d, q axis primary current respectively; Lm, is mutual inductance; Lr , LJ are resolved rotor, stator inductance respectively; P are poles; Rr, Rs are resolved rotor, stator resistance respectively, ohms; Vds Vqs are d, q axis primary voltage respectively, V; ÃŽÂ »dr and ÃŽÂ »qr are d, q axis rotor equivalent flux respectively, V-sec; ÃŽÂ »ds and ÃŽÂ »qs are d,q axis stator equivalent flux respectively, V-sec; à Ã¢â‚¬ °e is synchronous frequency, rps ; à Ã¢â‚¬ °r is rotor frequency, rps; , is rotor acceleration, rps2; Ts is electric motor torque, Nm. The limiting torque of the motor can be expressed by: Where à Ã¢â‚¬ °b, is motor base speed, rpm; à Ã¢â‚¬ °m is mechanical motor speed, rpm; Prated is the rater motor power, hp; Trated is the rated motor torque, Nm; Tm is mechanical motor torque, Nm. In addition to this, equations of motion for DC electric machine are: Where is the torque output of the machine proportional to the armature current, e is the back emf of the machine is proportional to the velocity of the rotor Drive Shaft: The drive shaft plays very important role in the drive train for transmitting the torque and rotation. They are subjected high torsion and shear stresses and therefore must have must have high stiffness. Below shown in the drive modelled using lumped inertias and their corresponding basic equations TDS =KDS (ÃŽÂ ¸T ÃŽÂ ¸W) + CDS (T W) Wheels: The forces acting on a vehicle with mass (m) and velocity (v) the longitudinal forces (Fe)acting on the vehicle gives Stationary model of the vehicle assuming all forces act through the centre of gravity and only in longitudinal direction. Gears: Assuming no losses in transmission the basic equation for gearing is But in reality there are viscous losses, sealing bearings drag contact friction. Losses vary with gear change but can be modelled as a loss torque tl acting on the transmission input shaft there can be shown as: Capacitor: It is device which stores energy an can be modelled by current equation Battery: Batteries are characterized by energy density, C-rating, cycle life, thermal run away and variations in temperature. Table below shows the comparison among different types of batteries with their technical specifications available in the market for HEV applications Property Lead Acid NiMH Lithium Cell Voltage Volts 2 1.2 3.6 Energy Density WH/Kg 30-40 50-80 100-200 Power Density W/Kg 100-200 100-500 500-8000 Maximum Discharge Rate 6 -10C 15C 100C Useful Capacity DOD% 50 50-80 80 Charge Efficiency % 60-80 70-90 ~100 Self Discharge %/Month 3-4 30 2-10 Temperature Range  °C -40 +60 -30 +60 -40 +60 Cycle Life Cycles 600-900 >1000 >2000 Micro-cycle Tolerant Deteriorates Yes Yes Robust (Over/Under Voltage) Yes Yes Needs BMS Cost per kWH  £100  £170  £150 Target A basic battery model might include an open circuit voltage and internal resistance Rc and Rd SOC Calculation: SOCic = initial SOC of the battery (assume 1; fully charged) Ibat = battery current that can be both positive and negative Qbat = battery capacity (Ah), needs converting to A.s for the simulation Simulation Tool Simulation X Simulation X is a multi domain program for modeling and simulation created by ITI GmbH. Some of its main features and capabilities are: Enables high level modelling platform for complex systems. Integrated with CAE design tool Over 30 standard industry specific libraries including automotive. Development of user specific libraries based on standard ones. Object oriented modelling language for simple and efficient modelling. Implementation of user based C code through external sources. Provides interface between various software available in market such as MATLAB/Simulink etc. Analysis tools available in Simulation X are: Transient Simulation: Capable of computing linear and non-linear models in the time domain. Steady State Simulation: Analyzing the models in periodic steady state condition dependent on a specific reference value. Linear System Analysis (Natural frequencies and mode shapes) : Efficiently generates damped and un damped natural frequencies of the complete system , time constants , eigen vectors, oscillations of state variables related to particular eigen frequencies. Linear System Analysis (Input Output Analysis): Enables linearization in the current operating point , analysis, export of state space matrices Modelling in Simulation X The vehicle type selected for the analysis of jerking and its effects is a sport utility vehicle (SUV) powered by a diesel engine shown earlier in figure 6 consisting a conventional diesel engine with crankshaft integrated starter generator (CISG), a DMF, a transmission gear box, a clutch between the transmission and the DMF, differential as a part of conventional power train and high voltage battery pack with power electronics on board as electric drive unit for the vehicle. Creating simulation models for hybrid power train requires various components of power train such as mechanics, hydraulics, electronics and pneumatics including the control aspects involved.

Foolish Pride in Judith Guests Ordinary People :: Judith Guest Ordinary People Essays

Foolish Pride in Ordinary People In the book Ordinary People, the author Judith Guest portrays a "normal" family, living in Lake Forest, struggling with many problems on the inside, but trying their best to hide their feelings. This book explores the need for everyone to act normal, and ordinary, and even though everyone in the book had a huge problem eating them from the inside, they didn't want anyone to know something was wrong. Many characters in the book hid from their problems. By the end of the book most of them managed to get better, but some of them were gone for good. In the book, Conrad struggled with perfection. He tried to be the obedient son, the good student, and eventually everything got to him so much, he felt the only way to escape was to try and kill himself. "An obedient boy. Polite, well mannered. Even in the hospital, with his fingernails bitten to bloody half-moons, the dark circles, bloody bruises under his eyes; always always his behavior was proper" (13). Conrad was strung too tight, fortunately by the end of the book he learned to relax, and not to stress too much about everything. Unfortunately this wasn't true for all the characters. Everyone viewed Conrad's mother, Beth, as perfect. Beth always had to have everything organized, neat. She had to be in control. Everything about her on the outside seems perfect. "Gracious as always, but Cal knows she doesn't like this. She is wearing a white-knit pantsuit, a long-sleeved black blouse, her hair tied back from her face with a black scarf. She does look gorgeous" (64). After her first son Buck died, and her second son Conrad tried to kill himself, she starts to realize that her family is falling apart, but she can't help them. Beth is all about appearance, how she and her family seem to other people. She can't handle talking about major problems, even when they involve the people she loves. Calvin, Conrad's father tries to be helpful to everyone. He is very caring to his son, and tries very hard with his wife Beth. It seems that Cal gives himself away to everyone, making sure his family is ok, but never worried about himself.

Heart of Darkness :: essays research papers

The Horror of Man Joseph Conrad’s â€Å"Heart of Darkness† is a tale of two men who work for an ivory company in the heart of Africa. The two men, Marlow and Kurtz, come to see the horror that hides behind the trappings of civilization and every day life, the true darkness within all mankind. Characterization, symbolism, and tone are important in Joseph Conrad’s construction of the main idea behind the â€Å"Heart of Darkness†. The author uses those things and more to build up the main Idea behind the story and make it evident to the reader.   Ã‚  Ã‚  Ã‚  Ã‚  Both Marlow and Kurtz can be seen as the main character in the story and for the story to be effective as a whole both have to exist. The author develops the character of these two men simultaneously even though Marlow does not come in contact with Kurtz until towards the very end of the story. The author builds up the characteristics of Marlow and Kurtz throughout the story so the reader knows that these men are like most people in their thinking, the reader then can see that Marlow and Kurtz are normal respectable people. The story is seen through Marlow, but the focus throughought the story is upon Kurtz almost from the moment Marlow reaches the first station in Africa. Kurtz character really begins to take shape about the time Marlow reaches the central station, he becomes known as an â€Å"exceptional man, of the greatest importance†. The reader sees the ambition that drives the man through the words of others. Even after Kurtz’s death, when Marlow tells Kurtz’s fiancà © of his death he lies to her about him because the truth â€Å"would have been to dark- to dark altogether†(224). The reader can see that Marlow still thought highly of the man and his character though, Marlow just knew what lurked beneath the surface of this man. The reader see’s that see the Marlow himself as being a respected man â€Å"the worst that could be said of him was that he did not represent his class†¦Marlow was not the typical seaman†(165). Wherever Marlow went he heard of Kurtz and Marlow was excited to meet the man, it almost became his goal. This can be seen when Marlow has gotten the steamboat close to the camp that Kurtz was at and the natives attacked, the manager comments â€Å"And by the way, I suppose Mr.

The Controversy of Interracial Marriages Essay -- Interracial Marriage

The Controversy of Interracial Marriages In today's society there is a lot of controversies over interracial marriages and dating. Interracial couples may have recently become very popular. An interracial marriage is defined as the marriage or unity of two heterosexual people, each of different races. In today's world it is happening more and more despite that many people do in fact disapprove of it and it does have an effect on the children and other family members.   Ã‚  Ã‚  Ã‚  Ã‚  As a starting point, let us make it clear that there are no references in scripture that forbid interracial marriages, although some people take scriptures out of context to prove otherwise. While in the past, people were more likely to stick with their own kind; society has seen a significant growth in interracial relationships. By integrating with different cultures and nationalities, we are doing away with hate, racism, and prejudice. The most common type of interracial marriage is where a black male marries a white female. According to the book in 1990, 46 percent of marriages were interracial. It is a fact that most interracial married people live far away from their families. Two people from two different backgrounds will likely experience a significant number of challenges and communication barriers. With different cultures come different customs. With different customs come misunderstandings. With misunderstandings come pain and grief.   Ã‚  Ã‚  Ã‚  Ã‚  Interracial relationships provide individuals...

Education Essay

â€Å"Education isn’t †¦. putting knowledge into souls that lack it, like putting sight into blind eyes†¦. The power to learn is present in everyone’s soul and †¦. the instrument with which each learns is like an eye that cannot be turned around from darkness to light without turning the whole body†¦. Education is the craft concerned with doing this very thing, this turning around, and with how the soul can most easily and effectively be made to do it†¦.. Education takes for granted that sight is there but that it isn’t turned the right way or looking where it ought to look, and it tries to redirect it appropriately. [518c-518d] This passage is from Plato, Republic VII, that talks about the education in particular. Plato emphasizes the description of education mainly of what it is and what it is not. In the first reading of this passage, you might experience getting confuse from the reality of what is education and the side of education not seen by man. At first, the reader might consider the viewpoints in this passage as unified to form a single thought or otherwise, to direct two different emphases in one unified thought. Singular thoughts perceiving contradictions and judgment may also arise. The intrinsic factor revolving in this passage is the value embedded in the word education. During the times of famous philosophers, Socrates and Plato, wisdom is indeed as valuable as gold. The value of human intellect is far more than the value of a castle. That is how they give importance in achieving wisdom. Education is everything for them. There are various points that identify the meaning of Plato’s Education that is being addressed not only to Socrates but also to the reader itself. Analyzing the passage reveals two opposing ideas embedded in this Plato’s perspective. Let us try to examine the passage, piece by piece. â€Å"Education takes for granted that sight is there†¦Ã¢â‚¬  In this part, Plato emphasizes two different terms particularly Education and Sight. Education is an important aspect in our society. According to the book, The Westminster Dictionary of Christian Spirituality, written by Wakefield (1983), the passage in Plato’s The Republic 518d reveals that an object of education is the moral-intellectual â€Å"turning of the soul. † The Christians are using this passage in order to imbue justification in their religious belief of renewed life. As for the Christians, they believe that acceptance of the Lord Jesus Christ can renew your life provided you are willing and humble enough to confess all your sins. This belief requires education for you to be aware of such existence. As the term implies, education can cause â€Å"turning of the soul. † Awareness is the fundamental gift that education brings to a person, hence revealing to the person the things he or she needs to know (p. 96). The term sight refers directly to what can the eyes perceive. It is the sensorial and physical perspective of what education is. As the saying implies, To see is to Believe. † The beginning of wisdom is not by seeing but by believing. The sight can only help you see what is physically present however, it does not reveal to you the principles, fundamentals and concepts that are indeed invisible to our eyes. Not everything is feasible to the eyes. The world may be present just the way it is seen by our naked eyes, however think of those things not yet revealed to us: those things that all the while we thought myths, stories and legends. Are these things false, human imagination, or only made up by the playful minds of our ancestors? Or, truth?  The contradicting concepts of sight and awareness through education collide in the case of material truth versus assuming truth. According to the passage, provides truth based on not only perceivable substances or materials but also those things that are unperceivable by any of our sensations. However, sight provides truth based on the material presence, actual existence and capacity to be perceived by the senses. This, however, is taken for granted by education. It pierces right into those things that are existing and reveals those things that are existing yet, not existing to the eyes. But that it isn’t turned the right way†¦Ã¢â‚¬  The word â€Å"that† pertains to education and not the sight. Education in this viewpoint is being redirected, not by sight nor any other means indicated. There are no mentioned evident factors that facilitate the redirection of education. In fact, this is ironic in the first statement. As analyzed in the first statement, education brings forth awareness however; in the next parts, it becomes redirected. If this is the case, then confusion is now present. If logic is applied then this means education is bringing in a redirected awareness. This condition manifests in some points of our lives. We thought that awareness brought by education is already the true and final awareness; however, in the end, we end up realizing that beliefs of ours are misconceptions. These are wrong beliefs that all the while we thought the right thing to follow. We move in this passage of redirected awareness. The next passage follows up, â€Å"Or looking where it ought to look †¦Ã¢â‚¬  In this phrase, the situation of education becomes quite changing. Education is likened to a person who can look back to the place that the person should be. In this case, awareness occurs in awareness as education realizes its direction. Education produces realization and this realization helps awareness to be redirected† is a complete statement of Irony if logic is applied. There are evident situation in which this case manifests in our lives. These conditions are those things that we do yet, we realize that we are not supposed to do this. However, out of pressing circumstances, we are forced to do such action, and the only thing that we can do is to look back and think about the things that we are suppose to do. Education’s awareness does not always fulfill its purpose of deviating our way. It helps us realize because we are aware but realizing is different from redirecting. In this phase, what we know is right. It is not anymore misconception because we know and we have justified its truth. The only problem is we do not put into action those things that we know. Lastly, â€Å"and it tries to redirect it appropriately†¦Ã¢â‚¬  It is the start of redirection. In this phase, truth, realization and decision making finally occurs. Education decides to bring about the reality of what is really happening and negating the influence of wrong directions. In the latter phases, first, truth is not present and other factors as well. Second, truth is already present as well as realization however, redirection is not yet beginning. In this phase, it is the start of new life. Education really means â€Å"turning of the soul. † The process that involves is very delicate and evident as well. The conditions in this phase occur in our lives. There are cases wherein we realize the truth of the situation, and then proceeds in the identification of those influencing factors that provided the wrong truth. After finding them, we analyze and provide solutions to correct this misconception source. The product of this correction, however, does not produce perfection of actions. Misconception is corrected by the reality of truth. However, truth varies from people to people’s perception and opinion. This condition might place a person into bondage of so-called truth. Again, we can consider this as misconception, however another case occurs wherein we become aware of the truth yet we cannot escape the misconceptions entangling our mobility. If we identify these entangling factors and decide in ourselves to be free from these entrapments, then we are indeed moving, redirecting and becoming appropriate. Education in the passe shows a man’s cycle of being trapped from wrong truth and turning out from this trap. This condition brings the ideal and right truths however, in the end it is still human beings. We hold our own lives. We hold our decisions. We hold our future. Awareness is their waiting to be heard and waiting to be perceived. Therefore, suffering from misconception is not always an excuse as well us ignorance, hence the saying â€Å"ignorance does not excuse any person from the law† is indeed true. It is our part to do the â€Å"turning of soul. † Education is not everything. By having the right education and our actions joint together is considered the fulfillment of everything we ought to do. Plato is in the end is right about his passage.

Kant on Suicide Essay

4. Explain and critically assess Kant’s argument that one has a duty to preserve one’s own life. As rational beings Kant believes we have a categorical duty of self-preservation to not wilfully take our own lives. Kant talks in depth about duty and believes we should act out of respect for the moral law. The will is the only inherent good, as we are only motivated by duty and nothing else. We should act only out of demands of the law, not from inclination, desires or to achieve a particular goal. Duty dictates we should never act or will something if we do not want it to become a universal law. Kant was against any form of suicide. He strongly believed that: in taking a life you treat humanity merely as a means to an end. Kant wouldn’t be interested in the suffering or pain caused to even a person who was terminally ill and wanted to end their life, nor would he take into consideration the family/friends suffering. In this essay I will be arguing that if we follow the categorical imperative it is immoral to sacrifice a life because it involves treating humanity merely as a means to an end. I will examine John Hardwig’s counter argument that we should end our own lives if more pain and suffering is caused by prolonging it/living it even if we are no longer a rational being. We must understand that Kant is saying; if I make a maxium e. g. – ‘if I am in unbearable suffering, I should take my own life’ – it must meet the universal law and be applied to everyone. Kant believes we ought to preserve our own lives because it is our moral duty (it is necessary and universal). John Hardwig however, would argue we also have the right to end our lives. Kant would dismiss this because ultimately humans are the bearers of rational life (e. g. it is too sacred to sacrifice). Suicide fails Kant’s Categorical Imperative on the following grounds: It seeks to shorten a life that promises more troubles than please, this would be killing yourself out of self-love; when in fact the real aim would be to live a life worth living, with more pleasure than difficulties. Kant isn’t claiming that it’s impossible for everyone to commit suicide or for everyone to will it (and therefore it becoming a universal law). He believes ‘it would not exist as nature; hence the maxim cannot obtain as a law of nature’. (Immanuel Kant, The Groundwork of the methaphysics of morals, Mary Gregor and Jens Timmermann, Cambridge University 2012, p45 emphasis added). Here Kant seems to be suggesting that suicide isn’t a natural path of life; that it goes against our purpose and that it’s a contradiction to end your life when your goal would be to have an enjoyable life. The idea that the destruction of life is incompatible with improvement suggests that nature couldn’t/wouldn’t allow self-love to be used in a way that is contrary to its purpose. There is surely an obviously contradiction here; in ending one’s life to prevent suffering, one is using one’s life mere means to an end, which automatically fails the categorical imperative. Take the case of Maria Von Herbert- she is clearly appealing to Kant, if under any circumstances; suicide is morally acceptable? He isn’t as blatant with her as in his writings, but let us not forget, Kant doesn’t see woman as rational beings. I agree with Rae Langton that Kant totally bypasses the reason Herbert is writing to him. He doesn’t confront her on suicide but instead reduces her problem to a moral dilemma (regrets lying or telling the truth ), which as an intelligent woman whom has read all his writings; she could work out for herself. Could this have made Kant certain that she did lie and therefore fail the kingdom of ends? Perhaps Kant is being hypocritical; he doesn’t tell Maria the whole truth of suicide merely reducing her to ‘a thing’. He tells Maria she should be ‘ashamed’ for not telling the truth to her former friend but, doesn’t this apply for himself too? Is he just avoiding the truth (states this is just as bad a lying) by not confronting her about suicide? Most likely he wants her to be autonomous and get to the reason herself. Hardwig disagrees with Kant. Take a different situation; Is a terminally ill person-needing 24/7 care, who is entirely financially reliant- only using their family as a means to an end? You can see this as a ‘two way street’ situation. Kant doesn’t look to consequences of an action; it wouldn’t matter to his philosophy that the ill person’s family suffers because they are preserving their life. But is there a flaw? (1) I ought to do my duty as long as I am alive; and (2) It is my duty to go on living as long as possible. Kant strongly believes that you can’t affirm life by taking your own. There is only one exception. Kant claims those who die in battle are ‘victims of fate’ (not simply suicide because they chose to fight). He holds the view that it is better to die in battle than to die of a wound in hospital. Kant believes it’s noble to risk our lives for others- nobody uses us as mere means and we follow our own maxium. We are no longer forced into serving for our country or deceived into joining (if this did happen it would fail the CI because we wouldn’t be treated as rational beings and would be used as mere means and not as ends in ourselves). John Hardwig strongly believes that life should be treated no differently from death. We are free to live in the way we want, so why aren’t we free to die in the way we want (when and how)? He also switches the question but Kant would simply say we have a duty to live. Hardwig has also argued that medical advances eliminate the threats of many terminal illnesses. He then concludes, if our continued existence creates signi? cant hardship for our loved ones, we have a duty to die. By continuing a live of suffering the burden that this person imposes on others is often great. One may have the duty to die in order to relieve them of these burdens. This argument seems to be based on fairness. Kant would refute this; suffering is a tool of reasoning and it ensures the development of mankind. Kant strongly believes that we should preserve our own lives. The argument though strong is flawed. 1- All duties are absolute- Kant doesn’t advise us on how to resolve conflicting duty (for example: help others vs. never kill). 2- He discounts moral emotions like compassion, sympathy, desire and remorse as appropriate and ethical motives for action. 3- Kant completely ignores the consequences of an action and is purposefully blind to following circumstances. He states that human life is valuable because humans are the bearers of rational life. We have the great capacity to think, organize, plan etc. and Kant holds this as being valuable. Therefore we should not sacrifice this for anything (as previously discussed autonomous creatures should not be treated merely as a means or for the happiness of another). There are also great issues with Hardwigs counter argument; if we agree that we have the duty to die; who has the duty to die? When do they have they duty to die? Although this argument is strong is some areas (greater burden), it is greatly flawed. It would be extremely difficult to universalize a maxium for everyone to follow so they could decide if at that moment they had the duty to die. A problem would also occur if the family disagreed with the ill person’s decision, which could cause great problems within society (though Kant would not look to consequences but they are greatly important to Hardwigs argument). I believe –and agree with Kant- that if we follow the categorical imperative it is immoral to sacrifice anyone at all (including yourself) because it involves treating the humanity in that person as merely a means to an end. I also accept and agree with his point that it seems to go against our purpose and is an unnatural path for us to take a life. I find it interesting that Kant believes suffering is a tool of development and therefore essential to us. Though John Hardwigs argument is partly convincing, if we were all given the choice of when we should die, would we find the right time? This would be very hard to govern, as people would of course take advantage of this right. I’ve found it hard to find a counter argument to Kant’s stance -without suffering there wouldn’t be cures and perhaps less happiness. Therefore I have to agree with Kant that it only allows us to grow and develop. Thus we do have the duty to preserve our own lives even if it is riddled with suffering.