start Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 OBJECTIVES: After studying Chapter 64, the reader should be able to: • • • Describe the different types of hybrid electric vehicles Explain how a hybrid vehicle is able to achieve an improvement in fuel economy compared to a conventional vehicle design Discuss the advantages and disadvantages of the various hybrid designs Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 OBJECTIVES: After studying Chapter 64, the reader should be able to: • • Describe HEV components, including motors, energy sources, and motor controllers Discuss the operation of a typical hybrid electric vehicle Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 KEY TERMS: assist hybrid • BAS • BEV • EV full-hybrid • HEV • HOV lane • hybrid • ICE • idle stop mode medium-hybrid • micro-hybrid-drive • mild-hybrid • motoring mode parallel-hybrid • power assist mode series-hybrid • series-parallel-hybrid • strong hybrid ZEV Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 HYBRID VEHICLE A hybrid vehicle, abbreviated HEV, is one that uses uses both an  internal combustion engine (ICE) and an electric motor to propel  the vehicle Most hybrids use a high­voltage battery pack and a combination  electric motor and generator to help or assist a gasoline engine.  The ICE used in a hybrid vehicle can be either gasoline or diesel,  although only gasoline­powered engines are currently used in hybrid  vehicles An electric motor is used to help propel the vehicle, and in some  designs, capable of propelling the vehicle alone without having to  start the internal combustion engine Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Background   In the early years of vehicle development, various  propulsion systems were used, including steam­, gasoline­, and  electric­motor­powered Early electric vehicles (EVs), also called battery electric vehicles  (BEV) used lead­acid batteries, an electric traction motor, and a  mechanical controller A traction motor is an electric motor used to rotate drive wheels and  propel the vehicle, which moves as a result of traction between the  wheel and the road surface The controller allowed different voltages to be applied to the  electric motor, depending on the needs of the driver.  Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Assume that an early electric vehicle used six 6­volt batteries. If the  batteries are connected in series, the negative terminal of one battery  is connected to the positive terminal of the second battery Two 6­volt batteries in series result in 12 volts, but the same current  as one of the batteries. Two 6­volt 500­amp/hour batteries in series,  then, would output 12 volts and 500­amp/hours.  Batteries connected in parallel increase the current, but the voltage  remains the same. Two 6­volt 500­amp/hour batteries in parallel,  would be six volts and 1,000 amp/hours Old electric vehicle mechanical controllers were able to switch all  six batteries in combinations of series and parallel configurations to achieve lower voltage for slow speeds and higher voltages for  higher speeds.  Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Electric vehicles did not have a long range and needed to have the  batteries charged regularly Electric vehicles were almost more popular than steam power in  1900, when steam had 40% and electric had 38% of the sales.  Gasoline­powered cars represented only 22% of the vehicles sold NOTE: Due to the oil embargo of 1973 and increased demand for  alternative energy sources, Congress enacted Public Law 94­413, the  Electric and Hybrid Vehicle Research, Development, and Demonstration  Act of 1976, which was designed to promote new technologies Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 In the late 1990s, several manufacturers produced electric vehicles,  using electronic controllers to meet the demands for zero emission  vehicles specified California law Electric vehicles were produced by Ford, Toyota, Nissan, and  General Motors Legislation was passed in California that included the zero  emissions vehicle (ZEV) mandate As a direct result of the California zero emissions vehicle (ZEV)  mandate originally calling for 10% ZEV, GM developed the  Electric Vehicle 1, known as EV1, leased to customers in California  and Arizona.  Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Figures 64–1 and 64-2 Views of the components of the General Motors electric vehicle (EV-1) Many of the features of this vehicle, such as regenerative braking and DC-to-DC converters currently used on hybrid vehicles, were first put into production on this vehicle Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Micro­Hybrid Drive System  A major fuel­saving feature of hybrid  electric vehicles is idle stop mode. The internal combustion engine is  stopped, instead of idling, while in traffic A system developed by Valeo, often  called a micro­hybrid­drive system,  uses a reversible starter/alternator It is used as a conventional alternator  when the engine is running, and as a  starter by transmitting power through  the drive belt system to start the engine.  Figure 64–11 A reversible starter/alternator is used to provide idle stop function to conventional vehicles This very limited and low cost system is called a micro-hybrid-drive Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 What is an Assist Hybrid? An assist hybrid-electric vehicle is a term used to describe a vehicle where the electric motor is not able to start moving the vehicle on electric power alone This type of hybrid would include all mild hybrids (36 to 42 volts), as well as the medium hybrids that use 144- to 158-volt systems Common Features of Most Hybrids that improve fuel economy: Idle stop  Turns off engine when the vehicle is stopped. When the  brake is released, the engine immediately starts. This ensures the  vehicle is not using fuel, nor creating CO2 emissions, when the  engine is not required to propel the vehicle Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Regenerative braking  When decelerating, the braking system  captures energy and stores it in the battery or other device for later  use, helping to keep batteries charged Power assist  The electric motor provides extra power using  current drawn from the battery to assist ICE during acceleration.  This power­assist mode enables the vehicle to use a smaller, more  fuel­efficient engine without giving up performance Engine­off drive­electric vehicle mode  The electric motor  propels the vehicle at lower speeds. The ICE is not being used  during acceleration, no fuel is being used and no emissions are  being released. When the hybrid is in this mode, it is essentially an  electric vehicle Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 LEVELS OF HYBRID VEHICLES The term hybrid refers to a type of vehicle. However, there are  different levels of “hybridization” on the market. Different vehicle  manufacturers use various hybrid technologies Mild Hybrid  Incorporates idle stop and regenerative braking, but not capable of using the electric motor to propel the vehicle  without help from the internal combustion engine A mild hybrid costs less, but saves less fuel (8% to 15%) compared  to a full hybrid vehicle and usually uses a 42­volt electrical motor  and battery package (36­volt batteries, 42­volt charging).  Examples include the GM Silverado pickup truck and Saturn VUE Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Medium Hybrid  Using voltages of about 144 to 158 volts, a  medium hybrid provides engine stop/start, regenerative braking,  and power assist Like a mild hybrid, it typically is not capable of propelling the  vehicle from a stop using battery power alone Fuel economy savings are about 20% to 25% Examples of a medium hybrid vehicle include the Honda Insight,  Civic, and Accord Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Full Hybrid  Also called a strong hybrid, a full hybrid uses idle  stop, regenerative braking, and is able to propel the vehicle using  the electric motor(s) alone Fuel economy savings are about 30% to 50% Examples include the Ford Escape SUV, Toyota Highlander,  Lexus RX400h, Lexus GS450h, Toyota Prius, and Toyota Camry Each vehicle manufacturer has made its decision on which hybrid  type to implement based on assessments of the market niche for a  particular model.  Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Hybrid Features by Make and Model Make/Model Idle Regenerative Stop Braking Motor Assist Engine Off Drive—EV Mode Chevrolet Silverado 1500/GMC Sierra Hybrid X X Ford Escape and Mercury Mariner Hybrid X X X X Honda Accord Civic Hybrid X X X X Honda Insight X X X X Toyota Prius X X X X Saturn VUE X X X X Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 EFFICIENCIES OF ELECTRIC MOTORS AND INTERNAL COMBUSTION ENGINES Internal Combustion Engines  An electric motor can have efficiency (including controller) of  over 90%, while a gasoline engine has efficiency of 35% or less An ICE does not have the overload capability of an electric  motor, which is why the rated power of an internal combustion  engine is usually much higher than required for highway cruising Operating smoothly at idle speed produces a much lower  efficiency than operating at a higher speed Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Maximum torque of an internal combustion engine is reached at  intermediate speed and the torque declines as speed increases  further There is a maximum fuel efficiency point in the speed range for the ICE, and this speed is optimized by many hybrid vehicle  manufacturers by using a transmission that keeps the engine  speed within the most efficient range Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Electric Motors  Offer ideal characteristics for use in a vehicle  because of the following factors: Constant power over all speed ranges Constant torque at low speeds needed for acceleration and hill  climbing capability Constant torque below base speed Constant power above base speed Only single gear or fixed gear is needed in the electric motor  transmission Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Watch Out for Motoring Mode When a hybrid electric vehicle is operating at low speeds, it is often being propelled by the electric motor alone, sometimes called motoring mode As a result, the vehicle is very quiet and is said to be operating in quiet mode During this time, the driver should be aware that the vehicle is not making any sound and should be careful when driving in congested areas Service technicians should also be extremely careful when moving a hybrid electric vehicle around the shop due to the silence of the vehicle Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 SUMMARY Hybrids use two different power sources to propel the vehicle A mild hybrid with a lower voltage system (36–50 volts) is capable  of increasing fuel economy and reducing exhaust emissions but is  not capable of using the electric motor alone to propel the vehicle A medium hybrid uses a higher voltage than a mild hybrid (140  150 volts) and offers increased fuel economy over a mild hybrid  design but is not capable of operating using the electric motor  alone Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 SUMMARY (cont.) A full or strong hybrid uses a high­voltage system (250–650  volts) and is capable of operating using the electric motor(s)  alone and achieves the highest fuel economy improvement of all  types of hybrids Early in vehicle history, electric vehicles were more popular  than either steam­ or gasoline­powered vehicles Legislation passed in California in 1998, which mandated zero  emission vehicles (ZEVs), caused the vehicle manufacturers to  start producing electric vehicles. When the law was changed to  allow the substitution of other vehicles that produced lower  emissions, but not zero, it helped promote the introduction of  hybrid electric vehicles (HEVs) Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 SUMMARY (cont.) A hybrid vehicle is defined as having two power sources to  propel the vehicle Electric motors are perfect for vehicle use because they  produce torque at lower speed, whereas internal combustion  engines need to have an increased speed before they produce  maximum power and torque Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 end Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458