3/1/13

Overview: Volkswagen Jetta Hybrid

The Jetta Hybrid has made its début at the Los Angeles Auto Show in production form, as it launches on the North American market. The new Jetta is powered by a 1.4-litre 150PS turbocharged petrol engine and a 20kW electric motor, driving through a seven-speed DSG gearbox. This combination delivers fuel consumption that is around 20 per cent. better overall than an equivalent petrol-powered vehicle — Volkswagen quotes a figure of ‘around 54mpg’.

Like the Touareg Hybrid, the Jetta is a series-parallel hybrid. It uses a decoupling clutch that can disengage the petrol motor for pure electric drive (or when coasting or braking), disengage the electric motor (for higher speeds or when the battery charge is low), or combine the two units for maximum power.

Using electric power alone, the Jetta Hybrid can be driven at speeds of up to 70km/h (44mph) and over a distance of two kilometres (1.3 miles), depending on conditions. For maximum performance, both the TSI engine and the electric motor combine, giving peak power of 170PS for a brief period. This is the first use of the 1.4-litre turbocharged engine in America, and it offers the same power and more torque (250Nm) than the atmospheric 2.5-litre engine that is commonly used in the Jetta in the U.S.

A lithium-ion battery supplies the energy for the electric motor. It is located behind the rear seat bench, making no compromises on interior space. The battery is made up of 60 individual cells, each with an energy capacity of 5Ah. Together they produce a nominal voltage of 220V and an energy capacity of 1.1kWh; installed weigh is 38.5kg. Cooling is provided by an integrated fan, operated by the battery’s own management system that performs diagnostic, monitoring and safety functions, including disconnecting the battery in the event of an accident.

With the extra weight of the battery, electric motor and additional safety modifications to the vehicle’s structure, the Jetta Hybrid weighs 100kg more than the non-hybrid Jetta at a little less than 1500kg.

Provided the battery contains sufficient charge, the Jetta Hybrid is switched to electric drive mode either automatically (at speeds of up to 60km/h or 37mph) or at the press of a button next to the gear lever (up to 70km/h or 44mph).

When the driver releases the accelerator pedal at higher speeds (up to 135km/h or 84mph), the TSI engine is decoupled, reducing drag torque losses, and maximising fuel efficiency. Under braking, the Jetta Hybrid switches to a battery regeneration mode, which decouples the TSI engine and uses the electric motor as a generator. The generating power of the motor rises with increased brake pedal travel. At higher speeds, or when the battery charge is depleted, the TSI motor provides extra power to recharge the battery; however, even in these situations the charging is interspersed with electric driving phases to maximise fuel efficiency.

Externally, the Jetta Hybrid can be identified by aerodynamic modifications including a new front spoiler, a rear diffuser and a rear spoiler that help to improve the car’s Cd value by 10 per cent. There are also new headlights with LED running lights, LED rear lights and unique 15-inch alloy wheels with low rolling resistance tyres. ‘Hybrid’ badges adorn the front wings, bootlid and modified front grille, where the Volkswagen logo is presented on a blue background for the first time.

The interior of the Hybrid is very much like that of any other Jetta, although the electric drive, along with a newly designed exhaust system, an acoustic windscreen and thicker front side windows help refinement. Volkswagen claims that this is the quietest vehicle Volkswagen has ever offered in this class.

One key interior difference is in the instruments. If the driver selects the ‘Hybrid’ menu in the multifunction display, the current drive mode is shown, while a meter indicates energy flow via arrows. The same screen also shows the battery charge state. Beneath the energy flow diagram is what is known as the ePower meter, which indicates the power provided by the electric motor.

The tachometer is replaced by the Power meter, a multifunction display on the left of the instrument cluster. This informs the driver of the operation of the hybrid system: ‘Ready’, ‘Charge’, ‘Eco’, ‘Boost’ or ‘TSI’. The audio system, meanwhile, has a ‘zero emissions’ menu. This offers a graphical display of the past 30 minutes of driving time, with a bar showing emissions each minute: a full, 100 per cent bar represents no emissions at all.

Standard equipment on the U.S.-spec SE model includes a two-zone climate control system that works without the petrol engine running, a ‘Premium 8’ sound system, Bluetooth phone integration, MDI interface for iPod connectivity and a leather-wrapped multifunction steering wheel. Moving up to SEL1 specification adds 16-inch alloy wheels, a glass sunroof, RNS 315 satellite navigation, electric driver’s seat adjustment, heated front seats and keyless entry. The top SEL2 specification adds to this further, with 17-inch wheels, fog lights, bi-xenon headlights with cornering function, a reversing camera and a 400W Fender sound system.

The Jetta Hybrid is available in North America now; there are no current plans to sell this model in the U.K.

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