Vaporized fuel purge controller for engine
AssigneeToyota Jidosha Kabushiki Kaisha
InventorNoritake Mitsutani
Life of this patent
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Abstract
A controller for purging an optimal amount of vaporized fuel in accordance with the operating conditions of an engine. The controller presumes the flow rate of the purged gas to be that when a purge valve is fully opened and uses the presumed value to calculate a target flow rate ratio. The controller than uses the target flow rate ratio and the actual intake pressure to calculate a duty ratio. This achieves a purged gas flow rate which compensates for a deviation that results from a characteristic of the purge valve.
Claims19
A purge controller for controlling a vaporized fuel processing mechanism in an engine, wherein the vaporized fuel processing mechanism has a canister and a purge valve for controlling flow of purged gas, which includes air and vaporized fuel adsorbed by the canister, into an intake system of the engine, wherein the engine undergoes purge control and air-fuel ratio control, and the purge valve is driven in accordance with the level of a drive signal, the purge controller comprising:
- a target level calculating means for calculating a target level of the drive signal, wherein the target level calculating means uses a parameter representing an operating condition of the engine and a predetermined target flow rate ratio of purged gas to presume the deviation from the purged gas flow rate ratio and the level of the drive signal that results from a characteristic of the purge valve and calculates the target level in accordance with the presumed deviation.
A purge controller for controlling a vaporized fuel processing mechanism of an engine that has an intake passage and undergoes air-fuel control, wherein the vaporized fuel processing mechanism has a purge valve to introduce into the intake passage a controlled amount of purged gas, which includes air and the vaporized fuel, and the purge valve is driven in accordance with the level of a drive signal, the controller comprising:
- a sensor for detecting an operating condition of the engine;
- and
- a computer for calculating a level of the drive signal, wherein the computer:
- presumes a fully opened flow rate of the purged gas introduced into the intake passage which is the purged gas flow rate when the purge valve is fully opened during the present engine operating condition detected by the sensor;
- calculates a ratio between the presumed fully opened flow rate and a target flow rate designated by the air-fuel control;
- and
- calculates the level of the drive signal based on the ratio and the present engine operating condition.
A purge control method for controlling a vaporized fuel processing mechanism of an engine that has an intake passage and undergoes air-fuel control, wherein the vaporized fuel processing mechanism has a purge valve to introduce into the intake passage a controlled amount of purged gas, which includes air and vaporized fuel, and the purge valve is driven in accordance with the level of a drive signal, the method comprising:
- detecting a present operating condition of the engine;
- presuming a fully opened flow rate of the purged gas introduced into the intake passage, which is the purged gas flow rate when the purge valve is fully opened during the present engine operating condition;
- calculating a ratio between the presumed fully opened flow rate and a target flow rate designated through the air-fuel control;
- calculating a level of the drive signal from the ratio and the present engine operating condition;
- and
- providing the purge valve with drive signal having the calculated level.
Dependencies are inferred from the claim text.