SUPERCHARGED DIRECT-INJECTION ENGINE
First Claim
1. A supercharged direct-injection engine comprising a supercharging device for compressing intake air, and an injector for directly injecting fuel into a combustion chamber, wherein:
- an excess air factor λ
as a ratio of an actual air-fuel ratio to a stoichiometric air-fuel ratio, at least in an engine warmed-up mode, is set to 2 or more in an entire engine-load region;
compressed self-ignited combustion is performed in a low engine-load region; and
a supercharging amount by the supercharging device is increased along with an increase in engine load in a high engine-load region to allow the excess air factor λ
to be kept at 2 or more.
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Accused Products
Abstract
Disclosed is a supercharged direct-injection engine, which comprises a supercharging device (25, 30) for compressing intake air, and an injector 10 for directly injecting fuel into a combustion chamber 5. In the engine, an excess air factor λ as a ratio of an actual air-fuel ratio to a stoichiometric air-fuel ratio, at least in an engine warmed-up mode, is set to 2 or more in the entire engine-load region. Further, compressed self-ignited combustion is performed in a low engine-load region, and a supercharging amount by the supercharging device (25, 30) is increased along with an increase in engine load in a high engine-load region to allow the excess air factor λ to be kept at 2 or more. The engine of the present invention can effectively reduce NOx emission, while improving fuel economy.
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Citations
7 Claims
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1. A supercharged direct-injection engine comprising a supercharging device for compressing intake air, and an injector for directly injecting fuel into a combustion chamber, wherein:
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an excess air factor λ
as a ratio of an actual air-fuel ratio to a stoichiometric air-fuel ratio, at least in an engine warmed-up mode, is set to 2 or more in an entire engine-load region;compressed self-ignited combustion is performed in a low engine-load region; and a supercharging amount by the supercharging device is increased along with an increase in engine load in a high engine-load region to allow the excess air factor λ
to be kept at 2 or more. - View Dependent Claims (2, 3)
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4. A supercharged direct-injection engine comprising:
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a supercharging device for compressing intake air; an injector for directly injecting fuel into a combustion chamber; a compression-ratio adjuster configured to variably set a compression ratio of the engine; and a dp/dθ
controller configured to control an increase rate of an in-cylinder combustion pressure,wherein; an air-fuel ratio at least in an engine warmed-up mode is set to a value leaner than a stoichiometric air-fuel ratio in an entire engine-load region; and compressed self-ignited combustion is performed, in a first engine operating region including a low engine-load region, under a relatively high compression ratio, and, in a second engine operating region on a high engine-load side relative to the first engine operating region, under conditions that;
the compression ratio is set to a value less than that in the first engine operating region by the compression-ratio adjuster;
the increase rate of the in-cylinder combustion pressure is reduced by the dp/dθ
controller; and
a supercharging amount by the supercharging device is increased. - View Dependent Claims (5, 6, 7)
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Specification