CICCO

In the context of reducing pollutant emissions and diversify fuel sources, the CICCO project (Compression Ignition Combustion Controlled by Ozone) aims at studying the potential of modifying air oxidizing properties by ozone addition in compression ignition engine. Indeed thanks to its oxidizing properties, ozone significantly lowers the auto-ignition temperature of fuels, including those with low Cetane number. Thus, in the case of direct injection engines (diesel engine), ozone injection at the intake would improve the critical phases of start or restart. It would also allow to adapt the fuel to the compression ratio, or to reduce the compression ratio to lower pollutant emissions directly at the source. In the case of HCCI or LTC combustion, ozone injection would enable to control cycle to cycle the ignition temperature of the fuel-air mixture and therefore enhance the ability to control engine combustion. An actuator prototype will be realized and used from the beginning of the program to demonstrate the concept of combustion controlled by ozone. This prototype will meet the criteria of energy cost and controllability. The characterization of chemical species formed during discharge (O3, O, OH, NO ...) and can occur during fuel oxidation will be studied. The effect of ozone will be analyzed on two single cylinder engines without optical or with optical access for measuring chemiluminescence and fluorescence (LIF) of the OH * radical, OH and formaldehyde. Its impact on advanced combustion modes like HCCI type will be well characterized in a first indirect injection engine. The potential of ozone addition in a standard late injection diesel engines will also be studied on a diesel optical engine. To address fuel diversification, the influence of ozone on different fuels with low Cetane value (fuel such as petrol, bio-fuel, gas, refinery intermediates between gasoline and Diesel ...) will also be studied. In parallel, the existing EADF model for 3D simulation of diesel combustion will be extended to take into account the presence of ozone in fresh gas, and will be used to carry out RANS simulations of the different engines used for experimental studies. These simulations will improve the understanding of fuel oxidation by ozone, capitalize the experimental results and identify new injection strategies, dilution and use of fuels. Finally, from the experimental and numerical results, the most promising engine adjustments will be made on a single cylinder research engine running on stabilized and transient operating points. An optimized ozonizer prototype will be used to demonstrate the feasibility to control the cycle to cycle combustion a compression ignition engine with a factory-made device.