<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>Originally posted by wmudavey:
It doesn't? I thought it had a CVT.<hr></blockquote>
It behaves like one, but the closes thing has that could be a transmission is the direct drive planetary gear.
<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>How it Works
The PowerSmart? transaxle case houses the traction motor and motor generator. The transaxle eliminates shifting, much like a continuously variable transmission, because it uses an electrical power loop in combination with a traditional mechanical planetary gear set to join the engine, motor and generator to the drive wheels.
The drive system combines a 65 kW permanent magnetic electric motor and 28kW generator with an Atkinson cycle variant of the Escape's Zetec four-cylinder engine. An electronic controller continuously adjusts the contributions of all of these power sources to maximize fuel efficiency. In addition, energy normally dissipated as heat during breaking is recaptured as electric energy and stored in the battery. This controller was developed through Ford's participation in the Partnership for a New Generation of Vehicles (PNGV) program.
The Atkinson cycle engine is up to 10 percent more efficient than a conventional four-stroke Otto cycle engine. The increase in efficiency is due to controlling pumping losses and optimizing the expansion ratio while maintaining a constant compression ratio.
The Atkinson cycle - also called the "five-stroke cycle" - works like this: intake, back-flow (partial expulsion to eliminate pumping losses), compression, expansion and exhaust. The combustion chamber volume is adapted to maintain a constant compression ratio to avoid knock while increasing the expansion ratio to optimize efficiency. Engineers convert the Zetec I-4 engine to an Atkinson cycle by changing the intake cam shaft to one with a very late valve closing and installing pistons that decrease combustion clearance volume. These changes result in a higher, 12.3:1 compression ratio.
The electric drive motor makes up for the low-end torque losses that are characteristic of five-stroke engines, making the Atkinson cycle ideal for hybridization. The PowerSmart? system offers both a series path and a parallel path for propulsion and can switch seamlessly between the two.
For example, the vehicle can run on the gasoline engine, the electric traction motor or both depending on the driving situation. The gasoline engine is most efficient at highway speeds, while the electric traction motor provides the most benefit at low-speed city driving.
The internal combustion engine shuts off when the vehicle is at rest, saving fuel. When the driver presses the accelerator, the electric motor restarts the vehicle almost instantly and has the ability to launch the vehicle on its own. When greater acceleration is needed, both the four-cylinder gasoline engine and the electric motor are used in tandem. This provides launch performance equivalent to the traditional Escape's powerful V-6 engine<hr></blockquote>
2003 Escape specs
Linear Mode
