Diesel engine exhaust particulate filter with intake throttling incineration control

Claim 2

A diesel engine exhaust filter and particulate incineration system in combination with a diesel engine having a normally unthrottled air induction system for admitting combustion air to the engine and an exhaust system for carrying off spent combustion products exhausted from the engine, characterised in that a combustion resistant filter (22, 24) is disposed in the exhaust system (16, 20) and is operative to collect and retain portions of the largely carbonaceous particulate matter contained in the engine exhaust products, . said filter being capable of withstanding without substantial damage internal temperatures sufficient to burn the collected particulate matter, that a throttle (30, 32) in the induction system is operable to restrict air flow into the engine to reduce the admittance of excess combustion air and thereby increase engine exhaust gas temperature, and that means (30, 32, 36, 38, 40) are provided to actuate said throttle periodically during engine operation to an air flow restricting burn mode capable of raising the particulates in said filter to their combustion temperature.

Claim 3

A diesel engine exhaust filter and particulate incineration system according to claim 1, characterised in that said means to actuate the throttle are adapted to operate under certain engine operating.conditions and to maintain said throttle mode for an interval adequate to burn retained particulates in the filter.

Claim 4

A diesel engine exhaust filter and particulate incineration system according to claim 1 or 2, characterised in that said actuating and control means are further operative to modulate the throttle position during the periodic burn mode to prevent the combustion temperatures within the filter from exceeding a predetermined temperature level higher than said particulate combustion temperature, above which damage to the filter may occur.

Claim 5

A diesel engine exhaust filter and particulate incineration system according to claim 1, 2 or 3 characterised in that said means are further operative to modulate the throttle position during the periodic burn mode to maintain an adequate supply of excess combustion air under all engine operating conditions to avoid an excessive increase in exhaust smoke during the particulate burnoff.

Claim 6

A diesel engine exhaust filter and particulate incineration system according to claim 4 characterised in that said means are further operative to open the throttle whenever during the particulate burnoff the engine is operated in the full fuel mode so as to avoid limiting engine performance.

Claim 7

A diesel engine exhaust filter and particulate incineration system according to claim 1, 2, or 3 characterised in that said system further includes supplemental means for periodically increasing exhaust gas temperature, said supplemental means being operative in conjunction with said throttle to provide exhaust particulate combustion temperatures in said filter over a wider range of engine operating conditions.