Two cycle diesel engine
AssigneeYamaha Hatsudoki Kabushiki Kaisha
InventorsHideaki Ito, Masanori Miyamoto
Life of this patent
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Abstract
A diesel engine operating on the two cycle crankcase compression principle and having a means for reducing nitrous oxide emissions under low and medium range speeds. This is done by throttling the scavenge air flow which can be accomplished either by throttling the air admitted to the crankcase chamber or bypassing a portion of the compressed air from the crankcase chamber back to the induction system. In addition, an exhaust control valve is provided for raising the compression ratio and the injection timing is advanced when the scavenge air is reduced so as to further improve the control of hydrocarbon and carbon monoxide emissions.
Claims28
An operator controlled two cycle crankcase compression diesel engine have a cylinder defining in part a combustion chamber, a crankcase, means for admitting at least an air charge to said crankcase, scavenge means for transferring a charge compressed i said crankcase to said combustion chamber, operator controlled speed control means for controlling the speed of operation of said engine and means for reducing the amount of air flow through said scavenge means at low and mid range engine speeds independently of said speed control means for reducing combustion temperature and NOx emissions.
A two cycle crankcase compression diesel engine as set forth in claim further including means for advancing the injection of fuel into the combustion chamber when the means for reducing the amount of air flow through the scavenge means is operative.
A method of operating an operator controlled two cycle crankcase compression diesel engine having a cylinder defining in part a combustion chamber, a crankcase, means for admitting at least an air charge to said crankcase, scavenge means for transferring a charge compressed in said crankcase to said combustion chamber, operator controlled speed control means for controlling the speed of operation of said engine and comprising the step of reducing the amount of air flow through said scavenge means without affecting the operator controlled speed control means at low and mid range engine speeds for reducing combustion temperature and NOx emissions.
Dependencies are inferred from the claim text.