Tank internal pressure-detecting device for internal combustion engines

Abstract

A tank internal pressure-detecting device for an internal combustion engine having an evaporative emission control system for controlling purging of evaporative fuel generated in a fuel tank thereof into an intake system thereof. An ECU interrupts purging of evaporative fuel by the evaporative emission control system for a predetermined period of time after the engine is started. The ECU causes control valves of the evaporative emission control system to open the interior of the fuel tank to the atmosphere, and stores a value of pressure within the fuel tank detected by a tank internal pressure sensor as a reference value while the purging is being interrupted and at the same time the interior of the fuel tank is opened to the atmosphere. The ECU corrects an output value of the tank internal pressure sensor, based upon the reference value stored.

What is claimed is: 
     
       1. A tank internal pressure-detecting device for an internal combustion engine having a fuel tank, an intake system, and an evaporative emission control system for controlling purging of evaporative fuel generated in said fuel tank into the intake system, comprising: tank internal pressure-detecting means arranged in said fuel tank for detecting pressure within said fuel tank;   purging interrupting means for interrupting purging of said evaporative fuel by said evaporative emission control system for a predetermined period of time after said engine is started;   opening means for opening an interior of said fuel tank to the atmosphere;   memory means for storing a value of said pressure within said fuel tank detected by said tank internal pressure-detecting means as a reference value while said purging interrupting means is interrupting said purging of said evaporative fuel into said intake system and at the same time said opening means opens said interior of said fuel tank to the atmosphere; and   correcting means for correcting an output value of said tank internal pressure-detecting means, based upon said reference value stored in said memory means.   
     
     
       2. A tank internal pressure-detecting device as claimed in claim 1, including inhibiting means for inhibiting operations of said purging interrupting means, said opening means and said memory means when a temperature of said engine is higher than a predetermined value. 
     
     
       3. A tank internal pressure-detecting device as claimed in claim 1, wherein said memory means stores said value of said pressure within said fuel tank detected by said rank internal pressure-detecting means as said reference value, when a second predetermined period of time has elapsed after said opening means started to open said interior of said fuel tank. 
     
     
       4. A tank internal pressure-detecting device for an internal combustion engine having a fuel tank, an intake system, and an evaporative emission control system having a canister having an air inlet port formed therein, an evaporative fuel-guiding passage extending between said fuel tank and said canister, a first control valve arranged across said evaporative fuel-guiding passage for closing and opening said passage, a purging passage extending between said canister and said intake system, a second control valve arranged across said purging passage for closing and opening said purging passage, and a third control valve arranged at said air inlet port of said canister for closing and opening said air inlet port, said tank internal pressure-detecting device comprising: tank internal pressure-detecting means for detecting pressure within said fuel tank;   valve control means for opening said first and third valves and at the same time closing said second control valve for a predetermined period of time after said engine is started;   memory means for storing a value of said pressure within said fuel tank detected by said tank internal pressure-detecting means as a reference value while said valve control means opens said first and third control valves and closes said second control valve; and   correcting means for correcting an output value of said tank internal pressure-detecting means, based upon said reference value stored in said memory means.   
     
     
       5. A tank internal pressure-detecting device as claimed in claim 4, including inhibiting means for inhibiting operation of said valve control means when a temperature of said engine is higher than a predetermined value. 
     
     
       6. A tank internal pressure-detecting device as claimed in claim 4, wherein said memory means stores said value of said pressure within said fuel tank detected by said tank internal pressure-detecting means as said reference value, when a second predetermined period of time has elapsed after said opening means started to open said interior of said fuel tank after said value control means started said opening of said first and third control valves and said closing of said second control valve. 
     
     
       7. A tank internal pressure-detecting device as claimed in claim 1, wherein said memory means stores a learned value of values of said pressure within said fuel tank detected by said tank internal pressure-detecting means as said reference value. 
     
     
       8. A tank internal pressure-detecting device as claimed in claim 4, wherein said memory means stores a learned value of values of said pressure within said fuel tank detected by said tank internal pressure-detecting means as said reference value. .Iadd. 
     
     
       9.  A pressure-detecting device for an internal combustion engine having a fuel tank, an intake system, and an evaporative emission control system for controlling purging of evaporative fuel generated in said fuel tank into the intake system, comprising: pressure-detecting means arranged in said evaporative emission control system for detecting pressure within said evaporative emission control system;   purging interrupting means for interrupting purging of said evaporative fuel by said evaporative emission control system for a predetermined period of time after said engine is started;   opening means for opening an interior of said evaporative emission control system to the atmosphere;   memory means for storing a value of said pressure within said evaporative emission control system detected by said pressure-detecting means as a reference value while said purging interrupting means is interrupting said purging of said evaporative fuel into said intake system and at the same time said opening means opens said interior of said evaporative emission control system to the atmosphere; and   correcting means for correcting an output value of said pressure-detecting means, based upon said reference value stored in said memory means. .Iaddend. .Iadd.10. A pressure-detecting device as claimed in claim 9, including inhibiting means for inhibiting operations of said purging interrupting means, said opening means and said memory means when a temperature of said engine is higher than a predetermined value. .Iaddend. .Iadd.11. A pressure-detecting device as claimed in claim 9, wherein said memory means stores said value of said pressure within said evaporative emission control system detected by said pressure-detecting means as said reference value, when a second predetermined period of time has elapsed after said opening means started to open said interior of said evaporative emission control system. .Iaddend. .Iadd.12. A pressure-detecting device for an internal combustion engine having a fuel tank, an intake system, and an evaporative emission control system having a canister having an air inlet port formed therein, an evaporative fuel-guiding passage extending between said fuel tank and said canister, a first control valve arranged across said evaporative fuel-guiding passage for closing and opening said passage, a purging passage extending between said canister and said intake system, a second control valve arranged across said purging passage for closing and opening said purging passage, and a third control valve arranged at said air inlet port of said canister for closing and opening said air inlet port, said pressure-detecting device comprising:   pressure-detecting means for detecting pressure within said evaporative emission control system;   valve control means for opening said first and third valves and at the same time closing said second control valve for a predetermined period of time after said engine is started;   memory means for storing a value of said pressure within said evaporative emission control system detected by said pressure-detecting means as a reference value while said valve control means opens said first and third control valves and closes said second control valve; and   correcting means for correcting an output value of said pressure-detecting means, based upon said reference value stored in said memory means.   
     
     
        .Iaddend. .Iadd.13.  A pressure-detecting device as claimed in claim 12, including inhibiting means for inhibiting operation of said valve control means when a temperature of said engine is higher than a predetermined value. .Iaddend. .Iadd.14. A pressure-detecting device as claimed in claim 12, wherein said memory means stores said value of said pressure within said evaporative emission control system detected by said pressure-detecting means as said value, when a second predetermined period of time has elapsed after said opening means started to open said interior of said evaporative emission control system after said value control means started said opening of said first and third control valves and said 
     
     
        closing of said second control valve. .Iaddend. .Iadd.15.  A pressure-detecting device as claimed in claim 9, wherein said memory means stores a learned value of values of said pressure within said evaporative emission control system detected by said pressure-detecting means as said reference value. .Iaddend. .Iadd.16. A pressure-detecting device as claimed in claim 12, wherein said memory means stores a learned value of values of said pressure within said evaporative emission control system detected by said pressure-detecting means as said reference value. .Iaddend.