CHAPTER 7 HYBRID AND ELECTRIC VEHICLES LEARNING OBJECTIVES KEY TERMS After studying this chapter, the reader will be able to: BEV 1. Describe the different types of hybrid electric vehicles. Combined charging system (CCS) 2. Explain how a hybrid vehicle is able to achieve DC Quick Charger (DCQC) an improvement in fuel economy compared to a conventional vehicle design. Electric vehicle (EV) 3. Discuss the advantages and disadvantages of the Hybrid electric vehicle (HEV) various hybrid designs. Internal combustion engine (ICE) 4. Describe HEV components, including motors, energy sources, and motor controllers. Plug-in hybrid electric vehicle (PHEV) 5. Discuss the operation of a typical hybrid electric vehicle. Range anxiety 6. Identify a plug-in hybrid electric vehicle (PHEV) Zero-emission vehicles (ZEVs) 7. Explain how the high-voltage batteries are recharged in a PHEV and EV vehicle 8. Discuss range anxiety 9. Discuss the battery capacity and range correlation of an EV 10. Describe the levels of chargers used to charge a PHEV or an EV . BACKGROUND In the late 1990s, several vehicle manufacturers produced electric vehicles, using electronic controllers to meet the Early Electric Vehicles demands for zero emission vehicles as specified by law in California at the time. Electric vehicles were produced by Early electric vehicles (EV), also called battery electric Ford, Toyota, Nissan, and General Motors. vehicles (BEV), were first used in the late 1800s, and it was not until the early 1900s that electric vehicles were practical Legislation was passed in California that included the following using rechargeable lead–acid batteries. revisions within the zero emissions vehicle (ZEV) mandate. As a direct result of the California zero-emission vehicle mandate • One the first was the 1903 Baker Electric Car, produced originally calling for 10% ZEV, General Motors developed by the Baker Motor Vehicle Company in Cleveland, the electric vehicle 1, known as EV1, and it was leased to Ohio. customers in California and Arizona. SEE FIGURE 7–1. • The Detroit Electric Car Company (1907–1939) produced very practical fully electric vehicles. The old electric vehicle mechanical controller was able to switch all six batteries in various combinations of series and parallel configurations to achieve lower voltage for slow speeds and higher voltages for higher speeds. Electric vehicles did not have a long range and needed to have the batteries charged regularly, which meant that electric vehicles could only be used for short distances. In fact, electric vehicles were almost more popular than steam power in 1900 when steam had 40% of the sales and electric had 38% of the sales. The gasoline-powered cars represented only 22% of the vehicles sold. Figure 7-1 View of the components of the General Motors electric Early Hybrid Electric Vehicles vehicle (EV1). Many of the features of this vehicle, such as A hybrid electric vehicle (HEV) vehicle is one that uses two regenerative braking, currently used on hybrid vehicles were first put different methods to propel the vehicle. A hybrid electric vehicle into production on this vehicle. uses both an internal combustion engine and an electric motor to propel the vehicle. In 1901, Ferdinand Porsche developed the Lohner-Porsche Mixte Hybrid, the first gasoline-electric hybrid automobile in the world. It was originally an electric- HYBRID ELECTRIC VEHICLES powered vehicle and then a gasoline engine was added to recharge the battery. One of the first hybrid electric car was Definition of Terms produced by the Owen Magnetic Motor Car Corporation, Most hybrid vehicles use a high-voltage battery pack and a manufactured in New York City and then in Wilkes-Barre, PA, combination electric motor and generator to help or assist a from 1915 until 1922. It failed because the fuel economy was gasoline engine. The internal combustion engine (ICE) used about the same as a conventional gasoline powered vehicle in a hybrid vehicle can be either gasoline or diesel, although yet cost more. Another vehicle that used both a gasoline only gasoline-powered engines are currently used in hybrid engine and an electric motor to power the vehicle was built by vehicles. An electric motor is used to help propel the vehicle, Woods Motor Company of Chicago, Illinois, and was called and in some designs, it is capable of propelling the vehicle the “Woods Dual Power” (1915–1918). alone without having to start the internal combustion engine. Newer Electric Vehicles First Widely Produced Hybrids Due to the oil embargo of 1973 and an increased demand for The hybrid electric vehicle did not become widely available alternative energy sources, Congress enacted Public Law 94- until the release of the Toyota Prius in Japan in 1997, followed 413, the Electric and Hybrid Vehicle Research, Development, by the Honda Insight sold in the United States starting in 1999. and Demonstration Act of 1976, which was designed to Then in 2001, the first Toyota Prius was introduced in the promote new technologies. United States. By 2010, there were several electric vehicles for sale although often in limited parts of the country and in limited numbers. Electric vehicles include the Tesla, Nissan Leaf, and Chevrolet Volt. SEE FIGURE 7–2. ONE, TWO, AND THREE MOTOR SYSTEMS One-Motor Hybrids Hybrid electric vehicles that use one electric motor include VW, Nissan, Honda, and General Motors. In these units, an electric motor is attached to the ICE (engine) crankshaft and is used to perform two functions: 1. Start the ICE engine 2. Act as a generator to charge the high-voltage batteries. Figure 7-2 The Chevrolet Volt is charged through a port located at General Motors also uses a belt alternator starter (BAS) the left front. system, which uses a belt-driven motor/generator attached to the front of the engine. Hybrids that use one motor are LEVELS OF HYBRID VEHICLES often called mild hybrids and usually are not able to power the vehicle using electric power alone. The term hybrid refers to a type of vehicle. However, there are different levels of “hybridization” among hybrids on the market. Different vehicle manufacturers use various hybrid Two-Motor Hybrids technologies. Hybrid electric vehicles that use two motors are the most commonly used hybrids by Toyota, Ford, and General Motors Mild Hybrid in their full-size two-mode trucks. Each electric motor serves two purposes: A mild hybrid will incorporate idle stop and regenerative braking but is not capable of using the electric motor to propel the 1. The motor/generator attached to the engine, usually vehicle on its own without help from the internal combustion labeled M/G1, is used to start the gasoline engine and to engine. A mild hybrid system has the advantage of costing charge the high-voltage batteries. less, but saves less fuel compared to a full hybrid vehicle and usually uses a 42-volt electrical motor and battery package 2. The motor/generator that is connected to the drive wheels, (36-volt batteries, 42-volt charging). An example of this type usually labeled M/G2, is used to propel the vehicle and of hybrid is the General Motors Silverado pickup truck plus the to recharge the high-voltage battery during deceleration Saturn VUE and Chevrolet Malibu. The fuel savings for a mild (regenerative braking). type of hybrid design is about 8% to 15%. Two-motor hybrid electric vehicles are full (strong) hybrids and are capable of propelling the vehicle using electric motor Medium Hybrid power alone for short distances. A medium hybrid uses 144- to 157-volt batteries that provide for engine stop/start, regenerative braking, and power assist. Three-Motor Hybrids Like a mild hybrid, a typical medium hybrid is not capable of Three-motor hybrid electric vehicles are usually two-motor propelling the vehicle from a stop using battery power alone. hybrids that use an additional electric motor to propel the rear Examples of a medium hybrid vehicle include the Honda wheels for all-wheel-drive capability. Hybrid electric vehicles Insight, Civic, and Accord. The fuel economy savings are that use three electric motors include the Toyota Highlander about 20% to 25% for medium hybrid systems. and Lexus RX400h/450h SUVs. Full Hybrid Features of Hybrids A full hybrid, also called a strong hybrid, uses idle stop The following are the most common features of hybrids that regenerative braking and is able to propel the vehicle using improve fuel economy: the electric motor(s) alone. Each vehicle manufacturer has made its decision on which hybrid type to implement based • Idle stop. The idle stop mode turns off the engine when on its assessment of the market niche for a particular model. the vehicle is stopped. When the brake is released, Examples of a full or strong hybrid include the Ford Escape the engine immediately starts. This ensures that the SUV, Toyota Highlander, Lexus RX400h, Lexus GS450h, vehicle is not using fuel, nor creating CO2 emissions, Toyota Prius, and Toyota Camry. The fuel economy savings when the engine is not required to propel the vehicle. are about 30% to 50% for full hybrid systems. • Regenerative braking. When decelerating, the braking PLUG-IN HYBRID ELECTRIC system captures the energy from the vehicle’s inertia VEHICLES and converts it to electrical energy which is stored in the battery or other device for later use. Regenerative Principles braking helps keep the batteries charged. A plug-in hybrid electric vehicle (PHEV) is a vehicle that is • Power assist. The electric motor provides extra designed to be plugged into an electrical outlet at night to power using electrical current drawn from the battery charge the batteries. By charging the batteries in the vehicle, to assist the internal combustion engine during it can operate using electric power alone (stealth mode) acceleration.