Patent ID: 8065990

Claim:
An internal combustion engine system, comprising: a cylinder providing a combustion chamber; fuel injection means in communication with the cylinder for injecting dimethyl ether fuel into the combustion chamber at a peak fuel injection pressure between 1000 bar and 1800 bar; an air intake line operatively connected to the cylinder, to provide air to the combustion chamber; an exhaust line operatively connected to the cylinder, to receive exhaust gas from the combustion chamber, and including means for recirculation of a portion of the exhaust gas to the air intake line; EGR control means for combining recirculated exhaust gas and ambient air; one or more compressors operatively connected to the air intake line, to pressurize said recirculated exhaust gas and/or ambient air before their entry into said combustion chamber(s); and a controller programmed to control the EGR control means to maintain the oxygen concentration of the combined recirculated exhaust gas and ambient air to a value below 17% and to control the quantity of dimethyl ether fuel injected in relation to the extent of pressurization of said recirculated exhaust gas or ambient air taken into the combustion chamber so as to maintain the level of nitrogen oxides (NOx) in the exhaust gas equal to or below 0.268 grams per kilowatt-hour.