Apparatus and method for controlling internal combustion engine
First Claim
1. An apparatus for controlling the air-fuel ratio of air-fuel mixture drawn into a combustion chamber of an engine, wherein an intake passage of the engine is connected to a canister by a purge line, wherein the canister adsorbs fuel vapor generated in the fuel tank and permits the adsorbed fuel vapor to be separated, wherein gas containing fuel vapor is purged as purge gas from the canister to the intake passage through the purge line, the apparatus comprising:
- a purge controlling device for adjusting purge flow rate, which is the flow rate of the purge gas flowing through the purge line;
a sensor for detecting the air-fuel ratio of the air-fuel mixture;
a computer for setting the amount of fuel supplied to the combustion chamber such that the detected air-fuel seeks a target air-fuel ratio;
wherein the computer computes the purge flow rate based on the state of the purge controlling device, and computes vapor concentration, which is the concentration of the fuel vapor contained in the purge gas, based on the difference between the detected air-fuel ratio and the target air-fuel ratio;
wherein, in accordance with changes of the computed purge flow rate, the computer obtains a concentration correction value for correcting the computed vapor concentration;
wherein, by taking into consideration of the difference between the time at which the purge flow rate is computed and the time at which purge gas having the computed flow rate is drawn into the combustion chamber, the computer corrects the computed vapor concentration by using the concentration correction value; and
wherein the computer sets the fuel supply amount in accordance with the computed purge flow rate and the corrected vapor concentration.
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Accused Products
Abstract
Gas containing fuel vapor is purged as purge gas from a canister to an intake passage through a purge line. An ECU computes purge flow rate, which is the flow rate of the purge gas, and computes vapor concentration, which is the concentration of the fuel vapor contained in the purge gas. The ECU obtains a concentration correction value in accordance with the rate of change of the computed purge flow rate. The ECU correct the computed vapor concentration by using the concentration correction value and by taking into consideration of the time at which the purge flow rate is computed and the time at which purge gas having the computed flow rate is drawn into the combustion chamber. The ECU sets the fuel supply amount in accordance with the computed purge flow rate and the corrected vapor concentration. As a result, the accuracy of the air-fuel ratio control during purging is improved.
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Citations
19 Claims
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1. An apparatus for controlling the air-fuel ratio of air-fuel mixture drawn into a combustion chamber of an engine, wherein an intake passage of the engine is connected to a canister by a purge line, wherein the canister adsorbs fuel vapor generated in the fuel tank and permits the adsorbed fuel vapor to be separated, wherein gas containing fuel vapor is purged as purge gas from the canister to the intake passage through the purge line, the apparatus comprising:
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a purge controlling device for adjusting purge flow rate, which is the flow rate of the purge gas flowing through the purge line;
a sensor for detecting the air-fuel ratio of the air-fuel mixture;
a computer for setting the amount of fuel supplied to the combustion chamber such that the detected air-fuel seeks a target air-fuel ratio;
wherein the computer computes the purge flow rate based on the state of the purge controlling device, and computes vapor concentration, which is the concentration of the fuel vapor contained in the purge gas, based on the difference between the detected air-fuel ratio and the target air-fuel ratio;
wherein, in accordance with changes of the computed purge flow rate, the computer obtains a concentration correction value for correcting the computed vapor concentration;
wherein, by taking into consideration of the difference between the time at which the purge flow rate is computed and the time at which purge gas having the computed flow rate is drawn into the combustion chamber, the computer corrects the computed vapor concentration by using the concentration correction value; and
wherein the computer sets the fuel supply amount in accordance with the computed purge flow rate and the corrected vapor concentration. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An apparatus for controlling the air-fuel ratio of air-fuel mixture drawn into a combustion chamber of an engine, wherein an intake passage of the engine is connected to a canister by a purge line, wherein the canister adsorbs fuel vapor generated in the fuel tank and permits the adsorbed fuel vapor to be separated, wherein gas containing fuel vapor is purged as purge gas from the canister to the intake passage through the purge line, the apparatus comprising:
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a purge control valve for adjusting purge flow rate, which is the flow rate of the purge gas flowing through the purge line;
a sensor for detecting the air-fuel ratio of the air-fuel mixture;
a computer for setting the amount of fuel supplied to the combustion chamber such that the detected air-fuel seeks a target air-fuel ratio;
wherein the computer computes the purge flow rate based on the opening degree of the purge control valve, and computes vapor concentration, which is the concentration of the fuel vapor contained in the purge gas, based on the difference between the detected air-fuel ratio and the target air-fuel ratio;
wherein, in accordance with the rate of change of the computed purge flow rate, the computer obtains a concentration correction value for correcting the computed vapor concentration, and stores a plurality of time-sequential values of the obtained concentration correction value;
wherein the computer computes a delay time according to the speed of the engine, the delay time reflecting the difference between the time at which the purge flow rate is computed and the time at which purge gas having the computed flow rate is drawn into the combustion chamber;
wherein the computer selects one of the stored time-sequential concentration correction values that corresponds to the computed delay time and uses the selected concentration correction value for correcting the computed vapor concentration; and
wherein the computer sets the fuel supply amount in accordance with the computed purge flow rate and the corrected purge concentration. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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19. A method for controlling the air-fuel ratio of air-fuel mixture drawn into a combustion chamber of an engine, wherein an intake passage of the engine is connected to a canister by a purge line, wherein the canister adsorbs fuel vapor generated in the fuel tank and permits the adsorbed fuel vapor to be separated, wherein gas containing fuel vapor is purged as purge gas from the canister to the intake passage through the purge line, the method comprising:
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adjusting purge flow rate, which is the flow rate of the purge gas flowing through the purge line, with a purge controlling device;
detecting the air-fuel ratio of the air-fuel mixture;
computing the purge flow rate based on the state of the purge controlling device;
computing vapor concentration, which is the concentration of the fuel vapor contained in the purge gas, based on the difference between the detected air-fuel ratio and the target air-fuel ratio;
obtaining a concentration correction value in accordance with changes of the computed purge flow rate;
correcting the computed vapor concentration by using the concentration correction value and by taking into consideration of the difference between the time at which the purge flow rate is computed and the time at which purge gas having the computed flow rate is drawn into the combustion chamber; and
setting the amount of fuel supplied to the combustion chamber in accordance with the computed purge flow rate and the corrected vapor concentration such that the detected air-fuel ratio seeks a target air-fuel ratio.
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Specification