VW’s Micro Gasoline Motors Promise a Punch

Paul Myles

TU-Editor

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9th December 2020

Volkswagen’s latest micro gasoline engines could power its passenger vehicle range from A to D segment cars.

Two versions of it TSI evo engine in three and four cylinder formats offer a claimed power output from 87bhp to 146bhp, enough to handle all the automaker’s vehicle models from the diminutive up! urban roundabout to the executive Passat cruiser.

It will be available with a capacity of 1.0-liters and 1.5-liters both feature and enhanced Miller combustion process.

The four-cylinder with 127bhp employ the Miller cycle on part load achieved by early closing of the inlet valves, reducing throttling losses and enabling a high compression ratios with 12.5:1 in the four-cylinder and 11.5:1 in the three-cylinder engine. To offset any loss in torque, the inlet camshaft can be continuously adjusted to increase filling during acceleration. The exhaust camshaft is also adjustable.
The turbocharger features variable turbocharger geometry (VTG) which permits absolute charge pressures up to 2.3 bar in the four-cylinder engine and even 2.8 bar in the three-cylinder variant. As a result, the engines can build up their maximum torque already at low rpm. In the 1.0 TSI, the turbocharger can withstand exhaust gas temperatures of up to 950 degrees Celsius and it achieves a maximum speed of 289,000 rpm.
The 1.5-liter also features cylinder deactivation to promote fuel efficiency. The system shuts down the second and third cylinders at low to medium loads and engine speeds by deactivating injection, ignition and the valve gear.
Both the three-cylinder and the four-cylinder engines with an output of 146bhp benefit from manufacturing technology to reduce friction in the crankshaft group. Here the cylinder walls consist of a 100-micrometer thick iron coating that is applied by plasma spraying. A map-controlled cooling module guarantees efficient thermal management in the 1.5 TSI and 1.0 TSI. An important component here is the exhaust manifold, which is integrated in the cylinder head contributing to the engine heating up quickly so that exhaust gas treatment starts early on.

Dr Frank Welsch, member of the board of management responsible for technical development at Volkswagen, said: “We already have 15 years of experience in building compact TSI engines, and we are consistently enhancing them with new technologies. The 1.0 TSI and 1.5 TSI are highly efficient, high-tech engines that have moved us well to the front in today’s competition.”

— Paul Myles is a seasoned automotive journalist based in London. Follow him on Twitter @Paulmyles_