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BMW Uses Multi-Stage Turbo To Boost Diesel Performance BMW will introduce a new twin-turbocharged diesel engine on its 5-series Touring station wagon in September which will boost power output from its 6-cylinder 3-litre oil burner by about 25 per cent. The new engine, developed from high-performance boat engines, uses what BMW calls multi-stage turbocharging to boost power and efficiency. Opel engineers are also believed to be working on similar technology, but BMW said it is about 2 years ahead. The engine produces a maximum output of 272 bhp, and 550 Newton metres of torque at 2,000 rpm, with 500 Nm available from 1,500 rpm. The current BMW 3-litre diesel produces 218 bhp. “This exceptional power is provided by two-stage turbocharging, a technology featured for the first time on a production car engine and so far only seen with high-performance marine drive systems,” said BMW. BMW said its engineers are overcoming the historical conflict between “turbo-lag” when accelerating from low engine speeds and the availability of high power reserves on fast roads. “BMW multi-stage turbocharger technology first pre-compresses intake air in the first turbocharger before the air is further compressed in the second charger through a multi-stage process. Then, under maximum pressure of 2.85 bar, the intake air flows through an intercooler directly into the combustion chambers where the enhanced cylinder charge ensured in this manner significantly boosts engine output from an unchanged 3.0 litres by 40kW/54 bhp versus the “basic” engine of the BMW 530d’s……. maximum output of 160kW/218 bhp,” BMW said in a statement. The technology broadens the engines rev range by 500 rpm to a maximum 4,800 rpm. Fuel efficiency remains about the same. According to BMW engine expert Wieland Bruch, the new diesel technology saves weight and space, and will therefore have an advantage over bulky V8 petrol or V-10 diesel motors. Bruch predicted that most other manufacturers of diesels will eventually produce similar multi stage diesels, not least because the technology involved does not involve any patented techniques. BMW will offer the new engine in the 5-series Touring and 535d saloon in September, with a six-speed automatic gearbox. Prices have yet to be announced. Neil Winton – March 30, 2004 |
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