Control device for internal combustion engine
AssigneeHonda Giken Kogyo Kabushiki Kaisha
InventorMasayuki Wakui
Life of this patent
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Abstract
In an engine 3, the phase of an intake camshaft 6 and/or an exhaust camshaft 7 for opening and closing intake valves 4 and/or exhaust valves 5 can be changed relative to a crankshaft 9, and NOx produced during lean-burn operation is occluded by a NOx occlusion catalyst 14. An ECU 2 of a control device 1 increases the amount of fuel such that an air-fuel ratio A/F used during the lean-burn operation is enriched by an enrichment amount R1, to thereby purge the NOx occlusion catalyst of NOx occluded therein and controls to change the phase CAIN of the intake camshaft 6 towards the advance side relative to the crankshaft 9.
Claims6
A control device for an internal combustion engine, said engine comprising:
- an intake camshaft for opening and closing an intake valve;
- an exhaust camshaft for opening and closing an exhaust valve;
- a cam phase changing mechanism changeable at least one of a phase of said intake camshaft and a phase of said exhaust camshaft relative to a crankshaft;
- and
- a NOx occlusion catalyst occluding NOx produced in a lean-burn operation, said control device comprising:
- an increasing unit increasing the amount of fuel to as to enrich an air-fuel ratio in said lean-burn operation by a predetermined degree of richness, to thereby purge NOx occluded in said NOx occlusion catalyst;
- and
- a control means performing at least one of a control changing the phase of said intake camshaft such that the phase of said intake camshaft advances relative to said crankshaft and a control changing the phase of said exhaust camshaft such that the phase of said exhaust camshaft retards relative to said crankshaft, in response to said predetermined degree of richness of said air-fuel ratio,
- wherein the advancement of the said intake camshaft and the retardation of said exhaust camshaft extend a valve overlapping period such that said intake valve and said exhaust valve are both open.
Dependencies are inferred from the claim text.