Technical Paper
Integrated Simulation and Engine Test of Closed Loop HCCI Control by Aid of Variable Valve Timings
2003-03-03
2003-01-0748
Homogeneous Charge Compression Ignition, HCCI, has the attractive feature of low particulate and low NOx emission combined with high efficiency. The principle is a combination of an Otto and a Diesel engine in that a premixed charge is ignited by the compression heat. One of the main challenges with the HCCI combustion system is to control the combustion timing/phasing for varying load and external conditions. A method to achieve this on a cycle-by-cycle basis is to vary the valve timing based on a feedback signal from the combustion timing of previous cycles. A combined engine and control simulation is performed. The simulations are accomplished with a commercial cycle simulation code linked with a commercial control simulation code. The simulations are iteratively verified against engine test data. Engine tests are conducted on a single cylinder engine equipped with at hydraulic valve system that allows a high degree of freedom in choosing the valve timings.