Evaporative fuel-purging control system for internal combustion engines
AssigneeHonda Giken Kogyo Kabushiki Kaisha
InventorsFumio Hosoda, Masayuki Habaguchi, Kazuhito Kakimoto, Toru Tochizawa, Masashi Uchiyama, Yoshiharu Ave
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Abstract
An evaporative fuel-purging control system for an internal combustion engine includes a mass flowmeter arranged across a purging passage of the engine for measuring a flow rate of a mixture of evaporative fuel and air being purged. A desired flow rate of the mixture is set according to operating conditions of the engine. The desired flow rate of the mixture is compared with a measured flow rate of the mixture obtained by the mass flowmeter, and the opening of a purge control valve arranged across the purging passage is controlled based on results of the comparison.
Claims10
In an evaporative fuel-purging control system for an internal combustion engine having a fuel tank and an intake passage, said evaporative fuel purging control system including a canister for adsorbing evaporative fuel generated from said fuel tank, a purging passage connecting between said canister and said intake passage for purging a mixture of said evaporative fuel and air therethrough into said intake passage, and a purge control valve arranged across said purging passage for controlling the flow rate of said evaporative fuel supplied to said intake passage, the improvement comprising:
- a mass flowmeter means arranged across said purging passage, for determining an actual flow rate of said mixture of evaporative fuel and air being purged, said mass flowmeter means including output characteristic determining means for determining an output characteristic of said mass flowmeter means so as to define a predetermined relationship between the actual flow rate and a measured flow rate of said mixture from said mass flowmeter means based on the concentration of evaporative fuel in the mixture such that said measured flow rate of said mixture varies relative to the actual flow rate of said mixture as the concentration of said evaporative fuel in said mixture varies wherein the output characteristic determining means of said mass flowmeter means has defined the output characteristic such that said measured flow rate of said mixture is larger than the actual flow rate of said mixture as the concentration of said evaporative fuel in said mixture increases;
- desired purging flow rate-setting means responsive to operating conditions of said engine for setting a desired flow rate of said mixture;
- and
- purge control means for comparing said desired flow rate of said mixture with said measured flow rate of said mixture obtained by said mass flowmeter means, and for controlling opening of said purge control valve based on results of the comparison.
In an evaporative fuel-purging control system for an internal combustion engine having a fuel tank and an intake passage, said evaporative fuel purging control system including a canister for adsorbing evaporative fuel generated from said fuel tank, a purging passage connecting between said canister and said intake passage for purging a mixture of said evaporative fuel and air therethrough into said intake passage, and a purge control valve arranged across said purging passage for controlling the flow rate of said evaporative fuel supplied to said intake passage, the improvement comprising:
- a mass flowmeter means arranged across said purging passage, for measuring a flow rate of said mixture of evaporative fuel and air being purged;
- desired purging flow rate-setting means responsive to operating conditions of said engine for setting a desired flow rate of said mixture;
- and
- purge control means for comparing said desired flow rate of said mixture with said measured flow rate of said mixture obtained by said mass flowmeter, and for controlling opening of said purge control valve based on results of the comparison, wherein said desired flow rate of said mixture is determined by multiplying a flow rate QENG of air drawn into said engine which is calculated by the use of the following equation:
- QENG=TOUT.times.NE.times.CEQ
- wherein TOUT represents a fuel injection period calculated according to operating conditions of said engine, NE rotational speed of said engine, and CEQ a constant for converting the product of TOUT.times.NE to said flow rate QENG, by a ratio PKQH of said desired flow rate of said mixture to said flow rate QENG, said ratio PKQH being determined according to operating parameters of said engine.
An evaporative fuel-purging control system for an internal combustion engine having a fuel tank and an intake passage, said evaporative fuel purging control system comprising:
- a canister for adsorbing evaporative fuel generated from the fuel tank;
- a first purging passage connected between said canister and the fuel tank;
- a second purging passage connected between said canister and the intake passage, said first and second purging passages being formed in conjunction with said canister so as to purge a mixture of evaporative fuel and air therethrough into the intake passage;
- a purge control valve arranged across said second purging passage for controlling the flow rate of said evaporative fuel supplied to said intake passage;
- mass flowmeter means connected between said canister and said purge control valve, for determining an actual flow rate of the mixture of evaporative fuel and air being purged based on variations in a concentration of evaporative fuel in the mixture, said mass flowmeter means including output characteristic determining means for determining an output characteristic of said mass flowmeter means so as to define a predetermined relationship between the actual flow rate and a measured flow rate of said mixture from said mass flowmeter means based on the concentration of evaporative fuel in the mixture such that the measured flow rate of the mixture varies relative to the actual flow rate of the mixture as the concentration of said evaporative fuel in the mixture varies wherein the output characteristic determining means of said mass flowmeter means has defined the output characteristic such that the measured flow rate of the mixture is larger than the actual flow rate of the mixture as the concentration of the evaporative fuel in the mixture increases;
- desired purging flow rate-setting means responsive to operating conditions of the engine, for setting a desired flow rate of the mixture;
- and
- purge control means for comparing the desired flow rate of said mixture with the measured flow rate of said mixture obtained by said mass flowmeter means, and for controlling opening of said purge control valve based on results of the comparison.
Dependencies are inferred from the claim text.