摘要:
In an evaporative emission-control system having a canister for trapping a fuel-vapor evaporated from the fuel tank and a purge control valve for executing a purging, an amount of fuel-vapor trapped in the canister is measured while the engine is stopped or in an idle state. The trapped fuel-vapor is purged from the canister and mixed with an air-fuel mixture when the amount of fuel-vapor trapped in the canister is sufficient for diagnosis while the vehicle is running in a predetermined driving condition. In this purge operation, a concentration of a vapor-laden air from the canister is measured and the occurrence of an abnormal state of the evaporative emission-control system is determined when a change of the concentration of the vapor-laden air after the purging is less than a predetermined value.
摘要:
A malfunction detection apparatus for detecting a malfunction in an evaporated fuel purge system in which fuel vapor from a fuel tank is adsorbed in an adsorbent in a canister and the adsorbed fuel vapor in the adsorbent is purged into an intake passage of an engine. The apparatus includes a detection part for detecting a concentration of fuel in the fuel vapor purged into the intake passage so that a change in the detected fuel concentration from a time when a purge cutting is performed to a time when a purging is performed after the purge cutting has been performed is detected, and a discrimination part for determining whether there is a malfunction in the system on the basis of the change in the detected fuel concentration by the detection part. The apparatus also includes a fuel vapor detection part for detecting a condition of fuel vapor in the fuel tank, and a purge cut time varying part for varying a purge cut time period for which the purge cutting is continuously performed, the purge cut time being varied by the purge cut time varying part in response to the detected fuel vapor condition by the fuel vapor detection part.
摘要:
A failure detection device that detects a failure occurring in an evaporative fuel purge system by detecting the pressure inside a vapor passage and a purge passage. The vapor passage and the purge passage are connected via a bypass passage. A pressure sensor is connected to either the vapor passage or the purge passage. An engine control unit is provided which judges that a failure has occurred in the evaporative fuel purge system when the pressure sensor detects a pressure equal to or higher than the predetermined pressure.
摘要:
A malfunction detection apparatus for detecting a malfunction in an evaporated fuel purge system in which fuel vapor from a fuel tank is adsorbed in an adsorbent in a canister and the adsorbed fuel vapor in the adsorbent is purged into an intake passage of an engine. The apparatus includes a detection part for detecting a concentration of fuel in the fuel vapor purged into the intake passage so that a change in the detected fuel concentration from a time when a purge cutting is performed to a time when a purging is performed after the purge cutting has been performed is detected, and a discrimination part for determining whether there is a malfunction in the system on the basis of the change in the detected fuel concentration by the detection part. The apparatus also includes a fuel vapor detection part for detecting a condition of fuel vapor in the fuel tank, and a purge cut time varying part for varying a purge cut time period for which the purge cutting is continuously performed, the purge cut time being varied by the purge cut time varying part in response to the detected fuel vapor condition by the fuel vapor detection part.
摘要:
In a double air-fuel ratio sensor system including two air-fuel ratio sensors upstream and downstream of a catalyst converter provided in an exhaust passage, the actual air-fuel ratio is adjusted in accordance with an air-fuel ratio correction amount calculated by using the output of the upstream-side air-fuel ratio sensor and an air-fuel ratio feedback control parameter such as delay time periods, skip amounts, or integration amounts calculated by using the output of the downstream-side air-fuel ratio sensor, and the calculation of the air-fuel ratio feedback control parameter is prohibited when the downstream-side air-fuel ratio sensor is in an abnormal state.
摘要:
In a double air-fuel sensor system including two air-fuel ratio sensors upstream and downstream of a catalyst converter provided in an exhaust gas passage, an air-fuel ratio correction amount is gradually changed in accordance with the output of the upstream-side air-fuel ratio sensor, and the actual air-fuel ratio is adjusted in accordance with the air-fuel ratio correction amount. The gradual-change speed of the air-fuel ratio correction amount is changed in accordance with the output of the downstream-side air-fuel ratio sensor.
摘要:
In an apparatus for diagnosing an abnormality in a fuel injection system in which an injection quantity is feedback-controlled by adjusting a first air-fuel ratio correction value so that an air-fuel ratio is equal to a target air-fuel ratio. The injection quantity is also adjusted by a second air-fuel ratio correction value. When the first air-fuel ratio correction value has reached a first upper limit value, the second air-fuel ratio correction value is set to a second upper limit value. When the first air-fuel ratio correction value has reached a second lower limit value, the second air-fuel ratio correction value is set to a second lower limit value. When the first air-fuel ratio correction value is outside of a predetermined range when a predetermined time has elapsed after the second air-fuel ratio correction value is set to either the second upper limit value or the second lower limit value, it is determined that a fault has occured in the fuel injection system.
摘要:
In a double air-fuel sensor system including two air-fuel ratio sensors upstream and downstream of a catalyst converter provided in an exhaust gas passage, a delay operation is performed upon the output of the downstream-side air-fuel ratio sensor, so that the actual air-fuel ratio is adjusted in accordance with the output of the upstream-side air-fuel ratio sensor and the delayed output of the downstream-side air-fuel ratio sensor.
摘要:
An internal combustion engine comprising three intake valves. The first intake valve and the second intake valve open at a crank angle near to the top dead center of the intake stroke. The third intake valve opens approximately at the center of the intake stroke. An air control valve is arranged in the second intake passage connected to the combustion chamber via the second intake valve. The air control valve is closed when the engine is operating under a partial load. A fuel injector is arranged in the third intake passage connected to the combustion chamber via the third intake valve. The injecting operation of the fuel injector is stopped during the intake stroke.
摘要:
An engine with three intake ports and three intake valves for each cylinder. The first intake port is a helical port. The remaining two intake ports have intake control valves, which open when the engine speed and the engine load are large and close when the engine speed and the engine are small. Air thus is introduced alternatively from the first port only or from all the ports. Fuel is injected in the third port between the corresponding intake valve and intake control valve.