Method and apparatus for controlling regeneration temperature in a diesel particulate trap

A method for controlling temperature in a diesel particulate filter in an exhaust gas stream of a diesel engine during regeneration thereof by combustion of soot collected therein, wherein said exhaust gas stream upon leaving said diesel engine has a residual oxygen content greater than about 6%, the method comprising the steps of:

• a) providing fuel to said exhaust gas stream ahead of said diesel particulates filter;
• b) combusting said fuel and said oxygen in said exhaust stream to reduce said residual oxygen content in exhaust gas passing through said diesel particulate filter;
• and
• c) selectively passing air through said diesel particulates filter to cool the combustion of soot in said diesel particulates filter when the diesel engine is in an idle mode or a low-demand mode.

A diesel engine comprising a system for controlling temperature in a diesel particulates filter in an exhaust gas stream of said engine during regeneration thereof by combustion of soot collected therein, said engine exhaust stream including oxygen, said system including

• a fuel source for providing fuel to said exhaust gas stream ahead of said diesel particulates filter, and
• an air source for controllably providing air to said exhaust stream ahead of said diesel particulates filter,
• wherein said exhaust gas stream upon leaving said diesel engine has a residual oxygen content greater than about 6%,
• wherein said fuel and said oxygen in said exhaust stream are combusted to reduce said residual oxygen content in said exhaust gas passing through said diesel particulate filter;
• and
• wherein said air from said air source is selectively passed through said diesel particulates filter to cool the combustion of soot in said diesel particulates filter when the diesel engine is in an idle mode or a low-demand mode.

A system for controlling temperature in a diesel particulate filter in an exhaust gas stream of a diesel engine during regeneration thereof by combustion of soot collected therein, said engine exhaust stream including oxygen, the system comprising:

• a fuel source for providing fuel to said exhaust gas stream ahead of said diesel particulates filter;
• an air source for providing air to said fuel source to produce said fuel, said air source further providing air to said exhaust stream ahead of said diesel particulates filter;
• a valve for selectively controlling air provided by said air source to said fuel source and to said exhaust stream
• wherein said exhaust gas stream upon leaving said diesel engine has a residual oxygen content greater than about 6%,
• wherein said fuel and said oxygen in said exhaust stream are combusted to reduce said residual oxygen content in said exhaust gas passing through said diesel particulate filter;
• and
• wherein said air from said air source passes through said diesel particulates filter to cool the combustion of soot in said diesel particulates filter when the diesel engine is in an idle mode or a low-demand mode.