Volkswagen has been a major purveyor of diesel-powered vehicles for decades. Last year, for instance, every fourth car produced at one of VW’s 62 global plants had a diesel engine aboard. And in the U.S., VW is the undisputed king. According to internal numbers, the Volkswagen Group owns 79 percent of America’s diesel market. Of the 111,285 diesel vehicles sold by VW last year, 95,823 were branded Volkswagen (the rest were Audi and Porsche). Now, the German auto giant has announced its next-gen modular diesel engine will be offered in the U.S.
A new breed of TDI engine named the MDB (short for Modular Diesel Baukasten, or Modular Diesel Toolkit in English) will arrive later this year in the 2015 Golf, Beetle, Beetle Convertible, Passat, and Jetta. It will eventually find its way inside the Golf Sportwagen, which is due at dealers in late 2015. The MDB is an evolution of the 2.0-liter 140-horsepower turbocharged BIN5-certified four-cylinder currently motivating a number of VW and Audi models.
According to Dr. Johannes Arning, the main man at Volkswagen AG’s Powertrain Management team, the MDB (codenamed EA288) needed to hit five development targets: lower CO2 output, reduced tailpipe emissions, improved performance, better comfort, and lower cost.
It had to be easily applicable in all vehicles utilizing numerous modular VW AG platforms (MQB, MLB, MSB), pass all global emissions standards (including ULEV125, ULEV3, EU6, and the U.S.’s BIN5, the most stringent on the planet), and
operate flawlessly on fuels having diverse sulfur and Cetane levels. It was a daunting task, said Dr. Arning, but he and his team did it. In six years’ time, they crafted an engine with a displacement range of 1.4 to 2.0 liters -- depending on application -- and in which the largest version has three times the power of the smallest. The engine’s basic architecture doesn’t vary per application, but the easy-to-swap attached systems and parts (like exhaust after-treatment systems) do.
Compared to the outgoing TDI, the MDB has an improved structure including a new crank gear with reduced-friction pistons; low-friction bearings for camshaft and balancer shafts; combined oil and vacuum pumps that change oil volume depending on driving situation; and an integrated valvetrain module with needle bearings. Thermal management has also been revamped, with a heat exchanger to quickly warm up the cabin, and improved charge air cooling via an efficient water-cooled module that operates independent of ambient air temperature. Exhaust gas after-treatment was redesigned, with the unit made more compact and placed nearer to the engine, while performance of the revised low-pressure exhaust gas recirculation (EGR) module has been improved by 90 percent from 200 millibars to 20-25 millibars.
In its 2.0-liter U.S. trim, friction is down 15 percent, raw emissions are down 40 percent, horsepower is up by 10 (to 150; torque remains at 236 lb-ft), and heating performance is improved. The charge air volume is also 40 percent smaller. Drivers will notice a wider power band, improved dynamic response, faster cabin heating, and 5-8 percent better fuel efficiency. They’ll be able to fill it with diesel blends up to B20. “We’ve got one MDB, which actually works in all regions of the world, in all cars that we sell,” said Dr. Arning. “And this is what gives us the huge benefit and advantage regarding scale effects. So if you're just thinking about equipping all the different cars -- an Audi A5, an Audi A3, and Passat, and Seat Leon, all different brands -- you don’t always need to start from scratch when you install it. You basically take some of the components that you need, put them together, and that’s it." “We’ve managed to reduce investment for new production versions, and also development costs for qualification into different vehicles, as well as piece costs. When you build 2.5 million engines per year, you obviously try to make the parts all the same, and this is what we’ve achieved with the MBD. This is also what has helped us stay ahead of the competition in diesel engine technology.” Alex Nishimoto contributed to this post
Source: Volkswagen
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