Volkswagen 2.0 TDI diesel engine ready for Euro 6d

17 December 2020

Volkswagen has provided an update on the Euro 6d version of their 2.0 TDI diesel.

“The two-liter TDI engine remains one of our most important engines,” said Frank Welsch, Member of the Board of Management responsible for Technical Development at Volkswagen. “It can be found in most of the brand’s models and in many of the Group’s models. For this reason, we spare no effort in consistently updating our successful diesel engine. In the version for the Euro 6d emission standard, it is now ready for the coming years.”

The 4-cylinder TDI engine with the internal designation EA 288 made its debut in 2012. The initial generations of the EA 288 engine—which used NOx adsorbers and early urea-SCR configurations, and were equipped with cycle beating control software—became the centerpiece of the Dieselgate emission scandal.

In 2019, the 2-liter diesel engine’s technology was updated for the new Golf. For this, a variant with lower output also replaced the previous 1.6 TDI. The updated engine, dubbed EA 288 evo, used a dual SCR technology to comply with Euro 6d final emission standard. The performance of the radiator for the low-pressure EGR system has been increased by 25%–thus reducing NOx formation in the combustion chamber in high-load phases. The injectors can operate with high precision because a sensor monitors needle closing, and can deliver up to nine injections per combustion cycle. The maximum injection pressure is up to 2,200 bar. Foam insulation under the engine cover panel and a new silencer improved acoustics. Both output variants of the 2.0 TDI—110 kW/150 hp and 85 kW/115 hp—feature two balance shafts to reduce vibrations.

Thanks to the twin dosing SCR system, the NOx emissions of both output variants of the new Golf 2.0 TDI are well below the limits of the Euro 6d emission standard of 80 mg/km, according to VW. The company also adopted the same 80 mg/km value as its target in the RDE test–equivalent to a 50% NOx reduction compared to the previous Euro 6d-temp standard.

The first SCR converter is a 3.4 liter SCR-on-filter (SCRF) unit, installed directly downstream of the engine. Its task is to convert more than 90% of NOx when the exhaust gas temperature is between 220 and 350°C and the vehicle is being driven normally. Thanks to its close proximity to the engine, it lights off shortly after a cold start.

The second SCR converter is installed in the underfloor position. It features a two-part design and, depending on the vehicle concept, has a volume of 2.5 to 3.0 liters. This catalytic converter installed further away from the engine performs the main share of NOx conversion at high loads and high exhaust gas temperatures. The exhaust gas, which can have a temperature of over 500°C when leaving the engine, has cooled down to approximately 350°C when it reaches this component—and this once again permits high conversion rates.

The 2.0 TDI with twin dosing SCR technology already powers many of the brand’s models, including in the Golf, Tiguan, Passat and Arteon model series. It is also widely used at other Group brands, with both transverse and longitudinal installation. Volkswagen said it is continuing to work intensively on further development of its diesel engine: one goal is operation in combination with a 48-volt mild hybrid system.

Source: Volkswagen