Mercedes has confirmed that it is pushing ahead with development of its unique Diesotto engine.
Reports had suggested work on the project was on the back-burner as the company concentrated on other future propulsion technology, such as electric, plug-in hybrid and hydrogen.
However, speaking at the Paris show, Professor Herbert Kohler, vice president of future mobility at Mercedes, confirmed the finished article would be ready for production within five years.
Nobody believes us, but it will happen, he told What Car? Three of the five hurdles we identified have been overcome. The engine is on the test bench and in development cars. It is coming.
The Diesotto engine combines the refinement of a petrol engine with the economy, low CO2 emissions and torque of a diesel.
It runs on standard petrol and has spark plugs at the top of each cylinder, but they don't fire on every cycle. They fire if the driver accelerates hard, but otherwise the engine relies on the natural heat generated by compression to ignite the fuel mixture, just like a diesel engine.
While the company cannot confirm exactly when the engine will reach a production car, it said in 2008 that the S-Class luxury car would be the first to get the engine.
However, the unit can be adapted for other cars the E-Class, for example although not for smaller models such as the A- and B-Class.