Website design By BotEap.comFuel economy simulation results for various engines in series hybrids are compared in Table 2 for the FUDS and FHWDS drive cycles. For both midsize and compact cars, fuel economy is significantly dependent on the technology used in the transmission. The use of diesel engines results in the highest fuel economy (miles per gallon of diesel fuel); however, from the point of view of energy consumption (kJ/mi) and CO2 emission (gm CO2/mi), the advantage of the diesel engine relative to gasoline engines should be discounted to reflect the higher energy and the carbon content per year. gallon of diesel fuel compared to gasoline.

Website design By BotEap.comThese discount factors are 15 to 20 percent. The simulation results also indicate that for the same type of engine, fuel economy can be 10 to 20 percent higher by using ultracapacitors instead of batteries as the energy storage device. The highest fuel economy is projected for vehicles that use fuel cells. The fuel economies (gasoline equivalent) of fuel cell vehicles using compressed hydrogen are approximately twice that of hybrid vehicles with direct injection gasoline engines and approximately 80 percent higher than those of vehicles with diesel engines. All fuel cell vehicle designs used a fuel cell balanced with a nickel metal hydride battery that allowed it to operate at high efficiency at all times.

Website design By BotEap.comIn comparisons between the fuel economies of conventional passenger cars and those using series hybrid transmissions, hybrid vehicles have the same weight and road load as conventional cars. Still, utilizing the hybrid driveline resulted in around a 50-percent improvement in fuel economy for the FUDS cycle and around a 10-percent improvement in the FHWDS (highway cycle). Fuel economy for conventional cars was taken from the EPA Fuel Economy Guide corrected by 10 percent for FUDS and 22 percent for highway cycle. These corrections were made because the actual dyno fuel economy test data had been reduced by these factors so that the published fuel economies were more in line with the values ​​experienced in the real world.

Website design By BotEap.comThe fuel economy of series and parallel hybrid vehicles is compared in Table 3 for compact, light-duty, and midsize cars. Series hybrids are supposed to work in maintain charge mode only (without recharging the battery from the wall socket), but parallel hybrids can work in charge maintain or charge depletion mode. For the parallel hybrid in charge depletion mode, fuel economy is given for gasoline and engine only (pp), including the energy required to recharge the batteries from the wall outlet. For hybrid vehicles using gasoline (port-injected) engines, fuel economy for parallel hybrid vehicles in maintain charge mode (batteries charged from the engine, not from the wall outlet) is 9 to 12 percent higher than that of series hybrids.

Website design By BotEap.comFor the engine efficiency (33%) assumed in the calculations, parallel hybrids operating in charge depletion mode (battery charged from wall outlet only) had only 1 to 4 percent better fuel economy equivalent to the same vehicle operating in charge maintenance mode. Fashion. If the batteries were recharged with electricity from a higher-efficiency engine, the fuel-saving advantage of the parallel hybrid in charge-depleting mode would be less.