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Ford Escape Hybrid
The Escape Hybrid is powered by a 2.3L 4-cylinder gasoline engine and a 70-kilowatt electric motor. The Escape Hybrid can run on the electric motor alone, the gasoline engine alone or a varying combination of these two, whatever gives the most economical operation. The Escape Hybrid never needs to be plugged in.
This electric traction (or drive) motor is what makes the Escape Hybrid a “full” hybrid. This is in contrast to a “mild” hybrid, a vehicle that merely shuts off as you coast to a stop and at idle but does not have an electric motor to assist in driving the vehicle.
Even among “full” hybrids, two sub-categories exist. In the system used by the Escape Hybrid and Toyota Prius, the electric motor without the gas engine actually propels the vehicle at low speeds. This electric motor will also kick in to help the gas engine when more acceleration is needed. In the system used by the Honda Civic Hybrid and Honda Insight, the electric motor helps the gas engine under heavy demand but will not propel the vehicle by itself.
The Escape Hybrid has a number of unique features. First, it uses a special version of the basic 2.3L 4-cylinder engine with the Atkinson-Miller combustion cycle instead of the traditional Otto combustion cycle. Second, the Escape Hybrid has an electronically controlled, continuously variable transmission (eCVT). This is connected to both the gasoline engine and the electric drive motor.
Third, the mid-size SUV has a massive starter motor for the engine. The gas engine automatically shuts off at lower speeds and at a stop. This high voltage starter motor restarts the engine in 0.4 seconds. Fourth, the Escape Hybrid uses a regenerative braking system. Somewhat like engine braking, this system converts braking energy into electricity and stores it in the high- voltage battery.
Fifth, the Escape Hybrid has a massive, 330-volt nickel metal hydride, high-voltage battery in the rear of the vehicle that powers the electric drive motor and the electric starter motor. Sixth, the Escape Hybrid has hydro-electric, power-assisted steering and brakes. It does not rely on the engine to turn a pulley for the power steering and does not use engine vacuum to power the brakes. You still have both power steering and power brakes with the gasoline engine shut off.
Seventh, and at the very heart of the hybrid drive system, is the electric drive (traction) motor. The Escape Hybrid can be driven at low speeds by the electric motor alone. It can also use this electric motor to assist the gasoline engine under heavy acceleration. This permanent-magnet, electric motor produces the equivalent of 94 hp! The electric motor is the most efficient at low speeds and under low loads...exactly where all gasoline engines are the least efficient.
Finally, the Escape Hybrid we tested came with the full-time AWD, i.e., “Intelligent 4WD” single-range system. The Escape operates in front-wheel drive until the front wheels lose traction. When that happens, a computer-controlled clutch transfers some power to the rear wheels.
The Escape Hybrid may be a good light-duty, enforcement vehicle for lower speeds and stop-go patrol areas like college campuses, parking enforcement, beach patrol, heavily urbanized areas, retirement communities, etc. At the retail level, the upcharge for the hybrid package is $3,500.
The more you are at low throttle and low speed, the more you coast to a stop, the more you stop and gently go, the better the gas mileage. The less you are under these conditions, the less you use the electrical drive and the lower the gas mileage. This cannot be emphasized enough!
Published in Police Fleet Manager, Jan/Feb 2009
Rating : Not Yet Rated
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