Engine with cylinder deactivation
AssigneeFord Global Technologies, LLC
InventorThomas Tsoi-Hei Ma
Life of this patent
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Abstract
A multi-cylinder spark ignition internal combustion engine is described having two banks of cylinders 10a, 10b. One bank of cylinders may be selectively disabled by cutting off its fuel supply while continuing to receive air. The exhaust system includes an NO.sub.x trap 20 to store NO.sub.x gases while the exhaust gases contain excess air. During part load operation, the engine is run with one bank of cylinders disabled most of the time during which NO.sub.x gases are stored in the NO.sub.x trap 20. In order to permit the trap 20 to be regenerated or purged periodically, both bank are fired at is the same time for short intervals to supply a stoichiometric or reducing mixture to the exhaust system.
Claims12
A multi-cylinder spark ignition internal combustion engine comprising:
- an intake system having a main throttle;
- two banks of cylinders connected to said intake system and a common exhaust system, with said exhaust system having a catalytic converter and a NO.sub.x trap;
- disabling means for selectively deactivating one bank of cylinders by interrupting fuel supply to said one bank of cylinders during part load operation while supplying air to said one bank of cylinders;
- and,
- means for resupplying fuel to said one bank of cylinders at periodic intervals to reactivate said one bank of cylinders, with a duration of said intervals being sufficient to regenerate said NO.sub.x trap.
A multi-cylinder spark ignition internal combustion engine comprising:
- an intake system having a main throttle;
- two banks of cylinders connected to said intake system and a common exhaust system, with said exhaust system having a catalytic converter and a NO.sub.x trap;
- and,
- disabling means for selectively deactivating one bank of cylinders by alternately interrupting fuel supply to said two banks of cylinders during part load operation, thereby deactivating one bank of cylinders at a time, while supplying air to said deactivated bank of cylinders, therebeing intervals during changeover of deactivation in which both said banks of cylinders are activated simultaneously, with a duration of said intervals being sufficient to regenerate said NO.sub.x trap.
Dependencies are inferred from the claim text.