Homogeneous Charge Compression Ignition (HCCI) engines

Homogeneous Charge Compression Ignition (HCCI) Engines Research

Details

Technology overview

Internal combustion (IC) engines are most commonly used for mobile propulsion in vehicles. Concerns about energy availability and pollutant emissions, such as nitrogen oxides and particulates, have driven concerted efforts towards the design of the next generation of internal combustion engines, capable of higher efficiency and lower emissions. Among the many new design and concepts, the Homogeneous Charge Compression Ignition (HCCI) engine design is considered one of the most promising.


The figure above illustrates the main features of HCCI engine design. An HCCI engine relies on compression to ignite a premixed mixture of fuel and air. As such, it employs a fully mixed mixture of fuel and air as spark ignition engines and it relies on compression as compression ignition engines to promote combustion. It combines the benefits of both gasoline and diesel engines: a) high thermodynamic efficiency, b) low mechanical losses, c) lean and low temperature combustion, d) ultra-low nitrogen oxides and e) no particulate emissions.

Research directions

Despite the advantages in terms of higher overall fuel efficiency and lower emission (compared to conventional IC engines), the HCCI engine suffers from several drawbacks such as the difficulty to control ignition timing, low power density, poor performance at high loads, and high unburnt hydrocarbon emissions. Those technological difficulties are a considerable impediment to a wide-spread adoption of HCCI technology and they are topic of current research. Charge stratification, i.e. the introduction of controlled inhomogeneities in the temperature and composition of the HCCI charge, is considered a viable solution to the difficulties mentioned above. The presence of inhomogeneities in the charge (or stratification) is a challenge to current HCCI modeling methods.

The Reative Flow Modeling Laboratory at KAUST is involved in the development of computationally affordable methodologies to numerically predict ignition in an HCCI engine with a thermally and mixture stratified charge. Additionally, we perform research in the fundamentals of the ignition process in HCCI engines under stratification.

Publications

Journal Articles

 F. Bisetti, J.-Y. Chen, J. H. Chen, E. R. Hawkes, Differential diffusion effects during the ignition of a thermally stratified premixed hydrogen-air mixture subject to turbulence, Proc. Combust. Inst. 32:1465-1472 (2009).​

F. Bisetti, J.-Y. Chen, J. H. Chen, E. R. Hawkes, Probability density function treatment of turbulence/chemistry interactions during the ignition of a temperature stratified mixture for application to HCCI engines modeling, Combust. Flame 64:571-584 (2008).

Y. F. Tham, F. Bisetti, J.-Y. ChenDevelopment of a highly reduced mechanism for isooctane HCCI combustion with targeted search algorithmJ. Engin. Gas Turb. Power 130:042804-1 (2008).