Smart fuels - photochemical ignition control

Some people believe that the era of combustion engines is soon ending and the transport sector will be completely electrified. However, combustion of liquid fuels will for a long time be needed in shipping, aviation and long-haul transport, where electrification is hard to imagine. It is important that combustion in the future occurs in the most optimal way in order to minimise stress on the environment. At the same time, it is evident that further technical optimisations of the combustion process in the form of an engine control unit will be difficult without introducing new concepts such as a method of optimising also the fuel in run-time, a smart fuel. Biofuels will be very well suited as the basis for the production of smart fuels and by using it in highly efficient engines with low emissions, the end use will be viable as well. 

The Smart fuels concept addresses this by using photochemistry. Components in the fuel react photo-chemically when exposed to light with a specific wave length in a photochemical reactor and form other components of different reactivity. The auto-ignition property and hence the ignition timing can thus be controlled by adjusting the ratio between reacted and unreacted fuel that is injected into the engine.

For some time now, researchers have worked on developing the so-called Homogeneous Charge Compression Ignition (HCCI) engine which combines (and exceeds) the high efficiency of the diesel engine with the low emissions of NOx and particles of the petrol engine. The main challenge related to HCCI combustion is that ignition timing cannot be controlled in the same way as in the diesel engine (by fuel injection timing) or in the petrol engine (by spark timing). The combustion can only be controlled kinetically, and one way to obtain this is to vary the reactivity of the fuel according to the operating conditions of the engine as proposed here. The HCCI technology is therefore especially suitable to demonstrate the smart fuel concept.