Ford Hybrid Electric Vehicle is on Horizon
6 January 1999
Ford Hybrid Electric Vehicle is on Horizon
DETROIT, Jan. 6 -- Ford Motor Company research engineers are developing an extremely fuel-efficient, product-feasible hybrid electric vehicle that is less complex and lighter than hybrids other automakers have demonstrated.
The hybrid powertrain is one of two being developed for Ford's P2000 Prodigy research vehicle, a five-passenger aluminum-bodied sedan that will be extremely light and aerodynamic.
Visitors to the 1999 North American International Auto Show in Detroit can preview Ford's progress in developing this customer-friendly hybrid vehicle at a dramatic new display of the vehicle's key components. The exhibit focuses on Ford's "low storage requirement" (LSR) hybrid, a candidate for the company's first mass production hybrid electric vehicle.
"The LSR hybrid is a high-value hybrid alternative," said Wayne Johnson, manager, Vehicle Electronic Systems. "It is simple, yet extremely fuel efficient, because we took a systems approach to optimize fuel economy.
"The LSR hybrid's total package -- DIATA engine, starter/alternator, automatically shifted manual transmission and high-power battery -- represents a promising approach for vehicles with breakthrough fuel efficiency."
The fuel economy of hybrid electric vehicles in city driving can be enhanced four ways:
-- The fuel to the engine can be turned off when no propulsion power is needed (for example, when coasting down a hill or when stopped at a traffic light) and the engine restarted instantly on demand.
-- The engine size can be decreased to improve efficiency, with electric power used to augment power demand when necessary.
-- Regenerative braking can be used to recapture and re-use energy that otherwise would be lost to heat when braking. The alternator transforms this braking energy into electrical energy, which is stored in the battery for later use.
-- Electric propulsion can be used with the engine off. (To maximize value, the LSR does not include this feature.)
Ford researchers determined that a hybrid with the first three capabilities could deliver fuel economy equivalent to a more complex and heavier hybrid with all four capabilities. In fact, they found that the LSR design required only very modest energy storage -- less than that of a conventional starter battery. Thus, LSR improves cost and reduces complexity.
Ford's LSR hybrid replaces the flywheel, starter and alternator with a single electric motor -- the starter/alternator -- packaged between the transmission and the engine.
In combination with a small, high-power nickel metal hydride battery and power electronics module, the starter/alternator can restart the engine in less than 0.2 second -- literally the blink of an eye.
It can generate the power for the vehicle electronic systems with 85 percent efficiency compared with less than 60 percent for a conventional system. And it can assist the engine as the vehicle accelerates and support the brakes during deceleration, thus recharging the battery for later use.
The starter/alternator module regulates the flow of electricity between the battery and the starter/alternator. It determines the precise amount of energy exchange using a variety of inputs, including accelerator and brake pedals. Battery voltages range up to 400 volts, with a peak current rating of 200 amps for 20 seconds and a continuous power rating of 25 kilowatts.
The LSR hybrid relies on an automatically shifted manual transmission that combines the operating ease of an automatic transmission with the efficiency of a manual transmission and is 20 percent more efficient than a comparable automatic transmission.
In Auto Shift Manual mode, the transmission shifts gears without driver input, similar to an automatic transmission. In Select Shift Manual mode, the driver controls the shift timing, while the automatic controls handle the shifting and clutch actuation, which eliminates the clutch pedal.
The latest-generation HEV is equipped with Ford's state-of-the-art, aluminum DIATA engine. The 1.2-liter compression-ignition, direct-injection engine is lighter and 35 percent more efficient than conventional engines. The four-cylinder DIATA generates 55 kilowatts, or 74 horsepower, at 4,100 rpm.
"Applying an integrated systems approach to the development of the HEV powertrain allowed us to use advanced technology, including the DIATA, that provides improved fuel economy and reduced emissions," Johnson said. "Although an LSR hybrid is simpler, lighter, smaller and less costly than other hybrid vehicles, it can supply the performance that customers expect from a Ford."
The LSR hybrid is being developed as part of Ford's participation in the Partnership for a New Generation of Vehicles (PNGV), a collaboration among Ford, General Motors, DaimlerChrysler AG, the U.S. Department of Energy and others.
