The star of the Jetta Hybrid show is unquestionably a powertrain that’s unique in the compact hybrid segment. Combining a 1.4-liter turbocharged four-cylinder gasoline engine with a 27-horsepower electric motor, the Jetta Hybrid is able to achieve a perfect balance of power, efficiency, and cleanliness.
The gasoline engine is one of Volkswagen’s latest EA211 series of small engines. This features many improvements over the previous EA111 generation, including lightweight aluminum construction, an integrated (into the head) exhaust manifold, and a toothed-belt drive for its double overhead camshaft valvetrain that incorporates variable intake timing. In fact, the only aspect to be carried over from its predecessor is the 82 mm cylinder spacing. The cylinder bore was decreased by 2 mm (to 74.5mm) while the stroke was increased to 80mm, a change which not only helps compactness, but also increases torque and presents an ideal canvas for adding boost (turbocharging or supercharging)— something the engineers at Volkswagen have spent many years perfecting.
The 1.4-liter TSI® engine in the Jetta Hybrid features a 10.5:1 compression ratio, direct fuel injection, and turbocharging to produce 150 hp at 5000 rpm. This engine’s turbocharging system offers incredible boost response thanks to its cleverly designed intake manifold, which enables the use of a surprisingly small, single-scroll compressor. The intercooler, uniquely, is integrated directly into the injection-molded induction pipe. This design generates maximum torque of 184 pound-feet at 1600 rpm.
A hybrid also needs electric power. For that, the Volkswagen engineers employed an innovative hybrid module—a single, integrated unit that incorporates both the electric motor and the clutch that connects it to the engine. This water-cooled motor can add 27 horsepower (20kW) to the mix, as well as a constant 114 lb-ft of torque. Combined, the system puts out 170 hp at 5000 rpm and184 lb-ft of torque at an impressively low1000 rpm, giving the car incredibly smooth acceleration. (The maximum torque is limited by the transmission.)
An 11.9-gallon fuel tank provides gasoline for the engine and a high-voltage battery placed above the rear axle powers the Jetta Hybrid’s electric motor. This 60-cell system produces a total voltage of 220 V, rated energy of 1.1 kWh, and pulse power of 32 kW. This battery pack is equipped with high-tech cooling and management systems to ensure safety, efficiency, and reliability.
An industry first, the Jetta Hybrid connects its powerplant to the pavement via a seven-speed, DSG® dual-clutch automatic gearbox. This DQ200 transmission is the most efficient unit in Volkswagen’s DSG arsenal and employs a dry-clutch design, as opposed to the wet-clutch arrangement seen in many other Volkswagen products. This unit can be operated as a pure automatic (“D” mode) or shifted manually. There is also a sport setting (“S” mode).
Thanks to the refined powertrain and features such as a newly designed exhaust system, an acoustic windshield, and thicker front side windows, the Jetta Hybrid is the quietest car Volkswagen has offered in the compact sedan class.