Evaporative fuel processing apparatus for lean-burn internal combustion engine
First Claim
1. An evaporative fuel processing apparatus for a lean-burn internal combustion engine, comprising;
- the lean-burn internal combustion engine capable of burning a mixture excessively containing oxygen;
a purge passage for introducing an evaporative fuel generated in a fuel tank provided in parallel to the lean-burn internal combustion engine into an intake system of the lean-burn internal combustion engine, the purge passage including a portion upstream of a throttle valve and a portion downstream of the throttle valve, the downstream portion connected between a fuel canister and the intake pipe;
evaporative fuel amount changing means for changing an amount of evaporative fuel to be purged by the purge passage based on at least a state of the lean-burn internal combustion engine; and
differential pressure changing means for changing a differential pressure between the upstream portion and the downstream portion of the purge passage in accordance with the amount of evaporative fuel to be purged.
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Accused Products
Abstract
In an internal combustion engine in which a throttle valve is substantially fully opened in most of the operating regions such as an in-cylinder injection type internal combustion engine, a technique is provided capable of effectively processing an evaporative fuel while stabilizing a combustion state of the internal combustion engine even in the case that an amount of evaporative fuel generated in a fuel tank or the like is increased. To achieve this technique, a purge amount of evaporative fuel is increased by increasing a differential pressure between an upstream portion and a downstream portion of a purge passage, and the differential pressure between an upstream portion and a downstream portion of a purge passage, and the differential pressure is adjusted in accordance with the combustion state of the internal combustion engine at that time, thereby making it possible to purge the maximum amount of evaporative fuel within a range in which the combustion state is not unstabilized.
39 Citations
19 Claims
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1. An evaporative fuel processing apparatus for a lean-burn internal combustion engine, comprising;
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the lean-burn internal combustion engine capable of burning a mixture excessively containing oxygen;
a purge passage for introducing an evaporative fuel generated in a fuel tank provided in parallel to the lean-burn internal combustion engine into an intake system of the lean-burn internal combustion engine, the purge passage including a portion upstream of a throttle valve and a portion downstream of the throttle valve, the downstream portion connected between a fuel canister and the intake pipe;
evaporative fuel amount changing means for changing an amount of evaporative fuel to be purged by the purge passage based on at least a state of the lean-burn internal combustion engine; and
differential pressure changing means for changing a differential pressure between the upstream portion and the downstream portion of the purge passage in accordance with the amount of evaporative fuel to be purged.
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2. An evaporative fuel processing apparatus for a lean-burn internal combustion engine, comprising:
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the lean-burn internal combustion engine capable of burning a mixture excessively containing oxygen;
a purge passage for introducing an evaporative fuel generated in a fuel tank provided in parallel to the lean-burn internal combustion engine into an intake system of the lean-burn internal combustion engine, the purge passage including a portion upstream of a throttle valve and a portion downstream of the throttle valve, the downstream portion connected between a fuel canister and the intake pipe;
evaporative fuel amount calculating means for calculating an amount of required evaporative fuel to be introduced into the intake system based on a state of the fuel tank and a state of the lean-burn internal combustion engine; and
differential pressure changing means for changing a differential pressure between the upstream portion and the downstream portion of the purge passage in accordance with the amount of required evaporative fuel. - View Dependent Claims (3, 4, 5, 6, 7)
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8. An evaporative fuel processing apparatus for a lean-burn internal combustion engine, comprising:
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the lean-burn internal combustion engine capable of burning a mixture excessively containing oxygen;
a purge passage for introducing an evaporative fuel generated in a fuel tank provided in parallel to the lean-burn internal combustion engine into an intake passage of the lean-burn internal combustion engine, the purge passage including a portion upstream of a throttle valve and a portion downstream of the throttle valve, the downstream portion connected between a fuel canister and the intake pipe;
a flow rate control valve for adjusting a flow rate of the purge passage;
combustion state determining means for determining whether a combustion state of the lean-burn internal combustion engine is stable when a purge of the evaporative fuel is executed;
differential pressure changing means for changing a differential pressure between the upstream portion and the downstream portion of the purge passage; and
purge control means for controlling at least the differential pressure changing means in accordance with the combustion state of the lean-bum internal combustion engine to adjust an amount of evaporative fuel to be introduced from the purge passage into the intake passage. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification