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Hybrid Electric Vehicle
- 1.
- 2. introductionA hybrid electricvehicle (HEV) augments an electric vehicle (EV) with a second source of power referred to as the alternative power unit (APU).
- 3. A hybrid canachieve the cruising range and performance advantages of conventional vehicles with the low-noise, low-exhaust emissions, and energy independence benefits of electric vehicles
- 4. Accordingly, the hybridconcept, where the alternative power unit is used as a second source of energy, is gaining acceptance and is overcoming some of the problems of pure electric vehicles.2
- 5. what is hybridelectric vehicleAny vehicle that combines 2 or more sources of power is said to be hybrid. For example, a moped(a motorized pedal bike),diesel-electric hybrid locomotives
- 6. Relies not onlyon batteries but also on an internal combustion engine which drives a generator to provide electricity and may also drive a wheel.
- 7. Alternative power unitto supply the power required by the vehicle, to recharge the batteries, and to power accessories like the air conditioner and heater. 3
- 8. Hybrid structureTwo typesof hybrid vehicle configurations
- 9.
- 10.
- 11. parallel hybridFuel tank,which supplies gasoline to the engine.
- 12. Set of batteriesthat supplies power to an electric motor.
- 13. Both the engineand the electric motor can turn the transmission at the same time, and the transmission then turns the wheels. 5
- 14. Parallel(contd.)When the APUis off, the parallel hybrid runs like an electric vehicle
- 15. When the APUis on, the controller divides energy between the drive train (propulsion) and the batteries (energy storage).
- 16. Under acceleration, morepower is allocated to the drive train than to the batteries. During periods of idle or low speeds, more power goes to the batteries than the drive train.
- 17. The batteries alsoprovide additional power to the drive train when the APU is not producing enough and also to power auxiliary systems such as the air conditioner and heater. 6
- 18. Series hybridSimilar toan electric vehicle with an on-board generator
- 19. The vehicle runson battery power like a pure electric vehicle until the batteries reach a predetermined discharged level.
- 20. At that pointthe APU turns on and begins recharging the battery.
- 21. The APU operatesuntil the batteries are charged to a predetermined level.
- 22. APU never directlypowers the vehicle7
- 23. Series (contd.)The lengthof time the APU is on depends on the size of the batteries and the APU itself.
- 24. Since the APUis not directly connected to the drive train, it can be run at its optimal operating condition; hence, fuel economy is increased and emissions are reduced relative to a pure IC engine vehicle. 8
- 25. components of HEVElectricdrive motors
- 26. to provide thepower for propulsion
- 27. converts electric energyto mechanical energy (motion) to drive the hybrid vehicle.
- 28. Direct Current Motors,Alternating Current Motors
- 29. The two possibleconfigurations of electric drive motors in a hybrid vehicle
- 30. single electric motorconnected to the wheels through a drive train and multiple electric motors, one located at each wheel.
- 31.
- 32. Supplies the baselinepower required to the vehicle, recharges the batteries and powers accessories such as the air conditioner and heater.
- 33. The APUcan consist of a mechanical type engine or a fuel cell.
- 34. Spark Ignition Engine,Compression Ignition Engines, Fuel Cells9
- 35.
- 36. to convert themechanical power into electrical power when used in a series hybrid.
- 37.
- 38. Peak power requiredin hybrid vehicles is met by devices like batteries, capacitors or a flywheel.
- 39. store energy andreadily release it when needed.10
- 40.
- 41. some of theenergy is converted into electrical energy and stored.
- 42. rotational energy ofthe braking mechanism generates electrical power and stores it in the batteries.
- 43.
- 44. contains two maincomponents-command and power components.
- 45. command component managesand processes the driver’s instructions.
- 46. power component chopspower flows to control the motor’s power intake.11
- 47.
- 48.
- 49. FUEL CELL HYBRIDVEHICLEElectric vehicle equipped with a fuel cell
- 50. Use hydrogen asa fuel and power the electric battery when it is depleted
- 51. In the 21century, the auto fuel will be replaced by such regenerative resources as hydrogen and the power system with traditional internal combustion engine will be replaced by hybrid system and finally be replaced by fuel cell power system to realize multi-resources, electric driving and zero emission.
- 52. For the fuelcell hybrid electric bus developed, high-pressure PEMFC and high-power NiMH battery pack forms the hybrid system.
- 53. In order toobtain the higher fuel efficiency and avoid the frequent charge & discharge of battery pack, the active control for the fuel cell pack to follow the driver’s pedal and the surplus peak power from NiMH battery pack passively is used.14
- 54. FUEL CELL HYBRIDPOWER TRAIN SYSTEMFuel cell Hybrid Power Train Structure
- 55. Fuel Cell IndirectPower System
- 56. FCE is connectedwith ESS in parallel after DC/DC converter
- 57. better for theoptimization and control of the FCE and is an economic selection for the fuel cell vehicle nowadays.15
- 58. Fuel Cell DirectPower System
- 59. FCE’s output isdirectly inputted to DC/AC and the ESS is connected with the FCE’s output in parallel after a bidirectional DC/DC.
- 60. FCE outputs powerdirectly into DC/AC, the FCE must have good dynamic response to output enough power quickly to meet the vehicle’s driving performance requirement and good voltage maintained performance to avoid the large voltage drop of bus line and the large torque drop of electric motor. On the other side, the FCE must be overlarge to avoid the possible damage.16
- 61. FUEL CELL ACTIVECONTROL SYSTEM17
- 62. The main controllerreceives the pedal signals from the driver. With the values of pedal, speed, the driving power required is calculated by look-up table of motor performance map.The target power of fuel cell engine is the sum of the driving power and the SOC-regulated power of battery pack. The target current of the DC-DC converter is real-time calculated by the target driving power divided by the bus voltage. The air compressor’s speed control is based on the target power of fuel cell engine.18
- 63. SYSTEM CONTROL STRATEGYInorder to properly determine the target power of Fuel cell and at the same time to realize the active control of fuel cell engine, it becomes very important to design a suitable and reasonable system control strategy. Two kinds of control strategiesConventional fuel cell output power oriented control strategy
- 64. Setting the FCEas the main power sources and controlling the FCE’s output power to follow the vehicle’s driving power requirement at some extent. The FCE is working on nearly for all of the driving time expect for the first cold start and small driving power requirement while battery pack is at high SOC.19
- 65. Fuel cell outputpower oriented control strategy based on FCE loading and unloading equations
- 66. similar to thefuel cell output power oriented control strategy as just mentioned above, but there has some new control characteristics as follows:
- 67. If cSOC >cSOC.t, the battery regulation power is zero and the battery actual output power is the power difference between Pd and Pf;
- 68. If cSOC≤ cSOC.t,the battery regulation charging power is considered and the target fuel cell power is the sum of driving power and charging power;
- 69. When the vehicleis braking, the fuel cell works at the minimum power and charges the battery pack with the regenerative braking;
- 70. The fuel cellengine works on nearly all of the driving time expect for the over high SOC battery pack and small driving power requirement at the first cold starting.20
- 71. Problems in FCHEVto transport and store hydrogen fuel in the vehicle.the cost of producing a powerful fuel cell is high.the size and weight issue as fuel cells powerful enough to power a car or truck are still rather bulky and heavy.However technology is maturing fast, so fuel cells may well prove to be a viable option in automotive technology in the not so distant future.21
- 72. HYBRID MILEAGE TIPSDriveslower - The aerodynamic drag on the car increases dramatically the faster you drive. For example, the drag force at 70 mph (113 kph) is about double that at 50 mph (81 kph). So, keeping your speed down can increase your mileage significantly. Maintain a constant speed - Each time you speed up the car you use energy, some of which is wasted when you slow the car down again. By maintaining a constant speed, you will make the most efficient use of your fuel. Avoid abrupt stops - When you stop your car, the electric motor in the hybrid acts like a generator and take some of the energy out of the car while slowing it down. If you give the electric motor more time to slow the vehicle, it can recover more of the energy. If you stop quickly, the brakes on the car will do most of the work of slowing the car down, and that energy will be wasted22
- 73. CONCLUSIONSUsing the concept of Hybridization of cars results in better efficiency and also saves a lot of fuel in today’s fuel deficit world.A hybrid gives a solution to all the problems to some extent. If proper research and development is done in this field, hybrid vehicle promises a practical, efficient, low pollution vehicle for the coming era. One can surely conclude that this concept and the similar ones to follow with even better efficiency & conservation rate are very much on the anvil in today’s energy deficit world.23
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