New Combustion Engine Uses Both Petrol and Diesel

The days of the compression engine are far from over. A new concept engine developed at the University of Wiscosin-Madison has demonstrated a thermal efficiency of 60 per cent in laboratory testing and uses both petrol and diesel. Called Reactivity Controlled Compression Ignition (RCCI), the technology might be just the one that could make internal combustion engines going on roads across the world for a while longer.

The test results indicate that the engine converts 60 per cent of the fuel that it uses as input into power, which is far more than any other internal combustion engine that is used in the world today. For example, the new 2.0 liter four-cylinder engine from Toyota has a maximum thermal efficiency of 40 per cent while the F1 engine form Mercedes-AMG achieves 50 per cent.

The RCCI uses two fuel injectors for each cylinder to form a mixture of a fuel with low reactivity like petrol and a fuel with high-reactivity, like diesel. Though this could be done in the case of any low and high reactivity fuels, the most interesting combination is that of petrol and diesel.
As part of the first stage of combustion process, a mixture of petrol and air enters the combustion chamber, and then diesel is injected. Both petrol and diesel start to mix and the piston moves upwards. At this point, more diesel is added to ignite the mixture.

This engine is more fuel efficient than a conventional diesel engine, and a lot cleaner form the emissions perspective. As of now, it is still very much in the testing stage. It remains to be seen whether it becomes commercially viable.