DaimlerChrysler has revealed details on what could be the successor to the current 1.8 litre E18 M271 used as Mercedes Benz’s flagship inline-4 engine. Quite a few car manufacturers have been combining the best qualities of both a petrol engine and a diesel engine, and this is DaimlerChrysler’s attempt called the DiesOtto concept.
This 1.8 litre DOHC inline-4 engine with variable valve control can produce 238 horsepower and 400Nm of torque, but consumes less than 6 litres of fuel per 100km – not on a small car but in the current Mercedes Benz S-Class!
Instead of the M271’s Kompressor supercharging, the DiesOtto uses turbocharging combined with direct injection. Now this is where the diesel characteristics come in – there is a special controlled auto ignition mode during low to medium engine speeds on low loads which ignites the air-fuel mixture through compression alone without spark ignition – this is called homogeneous combustion. For better emissions, the DiesOtto engine has a standard three-way catalytic converter
The DiesOtto will not be available in the market anytime soon, instead DaimlerChrysler will slowly be adding features from the DiesOtto concept to it’s production inline-4 engine one by one until the full concept is realised.
Technologies such as direct injection are already in production, and my guess is the next step would be for the Mercedes Benz inline-4 engines to go the turbocharging route instead of using a supercharger.
Have a look at the related posts below to read about engines with similar concepts being developed by other car manufacturers.