Two-Stage Combustion for Low Emissions without Catalytic Convertors
The concept of using two-stage combustion in a spark ignition engine has been tested in a single cylinder CFR engine. The engine was operated over an equivalence ratio range of 1.5 to 2.2 to evaluate the first stage of combustion. The product gas was analyzed for H2, CO, CO2, and hydrocarbons.
An atmospheric burner was operated with gasoline over the same equivalence ratio range of 1.5-2.2, and the resulting product gases were then burned in the CFR engine to test the second stage of combustion. Emissions of NOx, HC and CO of 0.1, 0.1, and 5 gm/IHP-hr were measured respectively. The engine indicated efficiency for the two-stage mode was essentially the same as for the single-stage mode.