The fifth engine option in VW’s new Jetta line-up is the acclaimed 1.4L TSI motor that will be combined with hybrid electric drive in the 2012 Jetta Hybrid. It joins the existing 2.0L, 2.5L, 2.0T and TDI engines as the most fuel-efficient Jetta in the new range. What’s more, it will be the first hybrid to use a seven-speed dual-clutch (DSG) automatic transmission when it comes to market later this year.
Unveiled today at the North American International Auto Show in Detroit, the Jetta Hybrid combines its turbocharged 1.4L gasoline engine with a zero-emissions electric motor. The result is an estimated combined fuel economy figure of 45mpg (yet to be certified by the EPA) as well as a 0-60mph time of less than 9.0 seconds – the 27hp electric motor being used to either improve economy or boost the small, four-cylinder motor when extra performance is required.
The hybrid solution should mean this Jetta consumes about 20% less fuel than a similar sedan with a conventional drivetrain. Although in city traffic, the advantage climbs to a little more than 30% as the electric motor does more of the work. In addition, the Jetta Hybrid can be driven in pure electric mode at speeds of up to 44mph for up to 1.2 miles, depending on operating conditions. This is a rather disappointing EV range but the batteries are mainly intended to assist rather than propel.
Not only is the 1.4-liter turbocharged gasoline powerplant economical but it’s also very light, weighing just 216 lb. this will further contribute to the fuel savings although the motor is no slouch. It’s rated at 150hp and 184 lb-ft of torque from 1400-3500rpm. Combined with its 27hp electric motor, the system should ensure the new Jetta Hybrid isn’t as recalcitrant as a Prius from the lights.
As with the VW Touareg Hybrid, this new Jetta features a similar clutch to decouple the gasoline engine from the drivetrain when in pure electric drive or when coasting for regenerative braking.
The electric motor is powered by a compact 220-volt, 1.1kWh lithium-ion battery located behind the rear bench seat, and weighing 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 cooling, which is handled by a fan mounted on the cells. The battery also has its own management system that performs safety and diagnostic monitoring functions to manage the temperature. The battery is disconnected when not in use or if the car is involved in a collision.
When the battery is sufficiently charged, the Jetta Hybrid can be driven up to 1.2 miles in pure electric mode up to 37mph if the electric motor is engaged automatically, or up to 44mph 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.
Like other hybrid vehicles, the Jetta 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 overall performance. In the Jetta Hybrid, when the driver releases the gas pedal prior to braking, the decoupling clutch disengages the engine to create a more efficient system.
When the driver brakes, all the deceleration is done by the brakes rather than a combination of the brakes, drivetrain drag and engine torque. This means more kinetic energy is released back into the battery.
The gasoline engine is stopped as soon as the car comes to a halt in city driving or stop-and-go traffic (provided the driver presses the brake pedal and that the battery is sufficiently charged). However, the heating, air conditioning and electric 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 (again provided the battery is sufficiently charged).
As soon as the driver lifts off the accelerator at speeds of up to 84mph, the TSI engine shuts down and is decoupled from the drivetrain to eliminate drag and the effect of engine torque. This results in further fuel savings.
The DSG transmission provides fast shifting and at 163 lb, is again lighter than a conventional automatic, as well as more compact.
Thanks to its lightweight engine, transmission and battery components, the Jetta Hybrid weighs in at less than 3310 lb, which is low for a hybrid vehicle. This compares to 3018 lb for the Jetta 2.5L or 2804 lb for the Jetta 2.0.
With the DSG lever in the ”S” or manual shift position, the drive system reacts to heavy throttle inputs by applying the maximum 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 170hp.
On spirited drives, or when battery capacity is low, the Jetta Hybrid is powered by the TSI engine alone. Excess power from the engine can also be used to charge the battery via the electric motor, which then acts as a generator. These active charging phases are interspersed with electric driving phases to realize the optimal fuel economy.
All relevant hybrid drivetrain information can be displayed on the multifunction digital display on the Jetta Hybrid’s instrument cluster. Under the “Hybrid” menu, the active drive mode is displayed in an energy flow diagram, and the direction of energy flow is visualized in the form of arrows. The battery charge state is shown on the same screen. Directly below is the ePower meter that indicates the relative power of the electric motor, but is only active in electric driving, E-mode, and “Boost” modes.
An additional multifunction display replaces the tachometer on the left side of the instrument cluster and informs the driver of the momentary operating state. These states are: ready to drive (“Ready”); battery regeneration (“Charge”); eco-conscious driving mode (“Eco”); boosting (“Boost”); or driving only with the TSI engine (“Off”). Electric operation, whether selected automatically or manually, is also indicated (E-mode).
The audio system’s display plays another role in informing the driver of what’s happening. When the goal is maximum economy, the audio display’s “Zero emissions” menu offers a graphic of the car”s zero emissions driving time. The values are shown in the form of percentages in a bar chart, where one bar represents one minute of driving. A value of 100 percent means the car was driven with zero emissions throughout the driving minute (ie, with the TSI engine off. The effective time period for this is 30 minutes).
Visually the Jetta Hybrid is distinguished by aerodynamic enhancements that include a new front air dam, rear diffuser and integrated rear spoiler. As a result, the Hybrid’s Cd is 10 percent lower than the stock Jetta.
In addition, the Jetta Hybrid is equipped with special 15-inch wheels with low rolling resistance all-season tires.
Other distinguishing features include a special radiator grille where the VW logo is integrated on a blue background for the first time. The new model is also identified by Hybrid badges on the grille, front fenders and trunk.
The Jetta Hybrid is the quietest car Volkswagen has even produced in the compact sedan class, thanks to a new exhaust system, an acoustically optimized windshield and thicker front side windows.
Three trim levels will be offered for the Jetta Hybrid. Standard features include Bluetooth technology, LED tail lights, SiriusXM satellite radio, special 15-inch wheels and the unique Hybrid body kit and badging.
Available premium features will include bi-xenon headlights and LED Daytime Running Lights, a power driver’s seat, heated front seats, the RNS-315 navigation system, a rear-view camera and Volkswagen’s exclusive Fender Premium Audio System.
Jetta Hybrid launches in North America in 2012 and will be the second gasoline-electric hybrid offered by Volkswagen alongside the Touareg.