For the first time in the U.S. market, Volkswagen is using its acclaimed 1.4-liter turbocharged gasoline powerplant, which weighs just 216 pounds. The downsized four-cylinder engine develops 150 horsepower and 184 pound-feet of torque delivered from just 1400 rpm up to 3500 rpm. Combined with the 20 kW (27 hp) electric motor, the system ensures that the new Jetta Hybrid is a genuinely sporty vehicle.
As in the Touareg Hybrid SUV, the Jetta Hybrid features a clutch that decouples the gasoline engine from the drivetrain when in pure electric drive or coasting modes.
State-of-the-art battery: A lithium-ion battery supplies the energy to the electric motor. The compact 220-volt, 1.1 kWh battery is integrated behind the rear bench seat and weighs less than 80 lb. The battery consists of 60 individual cells with a combined energy capacity of 5 Ah. The frequency of the discharge and charge cycles in hybrid operation requires high-performance battery cooling, which is handled by a fan mounted directly on the device. The battery also has its own management system that performs safety, diagnostic, and monitoring functions as well as temperature management. The battery is disconnected when it’s not in use or if the car is involved in a collision.
Efficient dual-clutch transmission: Power is taken to the front wheels via a seven-speed DSG® dual-clutch transmission that operates automatically and efficiently, as well as providing super-fast shifting. Downsizing was achieved here, too: at 163 lb, the DSG transmission weighs significantly less than a conventional automatic and is also much more compact in its construction. Thanks to its lightweight drive components, the weight of the Jetta Hybrid was only increased by 221 lb despite the addition of a battery system. The car weighs in at less than 3310 lb, which is low for a hybrid vehicle.
Zero emissions electric operation: When the battery of the Jetta Hybrid is sufficiently charged, the Jetta Hybrid can be driven over a distance of up to 1.2 miles in pure electric mode, with zero emissions. The Jetta Hybrid works as an electric vehicle up to 37 mph if the electric motor is engaged automatically or up to 44 mph if the driver presses the E-mode button to the right of the shift lever. About a third of the potential fuel savings in the Jetta Hybrid comes through electric driving.
Regenerative braking, with a wrinkle: Like other hybrid vehicles, the Jetta Hybrid uses regenerative braking, feeding kinetic energy into the battery to be stored as electrical energy that can be used in the electric drive mode or for boosting the powertrain’s overall performance. In the Jetta Hybrid, this is achieved more efficiently because when the driver releases the gas pedal prior to braking, the decoupling clutch disengages the engine. When the driver begins to slow down the car, all the retardation is done by the brakes rather than a combination of the brakes, drivetrain drag, and engine torque. This means that more kinetic energy is released back into the battery.
Stop and Go: The gasoline engine is stopped as soon as the car comes to a halt in city driving or stop-and-go traffic, provided that the driver presses the brake pedal and that the battery is sufficiently charged. However, the heating and air conditioning and electrically operated comfort and convenience features, such as the audio system, continue to operate. Unlike conventional hybrid systems, when the Jetta Hybrid’s gasoline engine is stopped, the engine is disengaged via the decoupling clutch to give a pure electric drive mode when the car moves off again—provided that the battery is sufficiently charged.
’Coasting’ without the engine: As soon as the driver releases the accelerator pedal at speeds of up to 84 mph, the TSI® engine shuts down and is decoupled from the drivetrain to eliminate driveline drag and the effects of the engine’s torque. This results in further fuel savings.
With the lever in the ”S” position or in the manual shift gate, the drive system reacts to heavy throttle inputs by applying the maximum amount of propulsive power. The same applies when the driver kicks down. In these situations, the power of the electric motor and the gasoline engine combine to provide the peak output of 170 hp.
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