Honda Giken Kogyo Kabushiki Kaisha

Honda Giken Kogyo K.k.

Hiroaki Muramatsu

Yuichi Shimasaki

Hiroaki Kato

Takuya Aoki

Takashi Komatsuda

Shinichi Kitajima

Akihisa Saito

Takayoshi Nakayama

Tetsu Teshirogi

Hideo Furumoto

Yoshihiko Kobayashi

Teruo Wakashiro

Hiroshi Kitagawa

Hiroshi Maruyama

Toshiaki Ichitani

Toshikatsu Takanohashi

Hajime Uto

Toshikatu Takanohashi

A failure detection system detects a failure occurring in an exhaust secondary air supply system of an internal combustion engine, and has a catalytic converter installed in an exhaust pipe of an exhaust system of the engine for reducing pollutants from exhaust gases emitted from the engine, a conduit connected, at one end, to the exhaust pipe at a location upstream of the catalytic converter and an air pump connected to an opposite end of the conduit for supplying compressed air in the conduit. The conduit is closed by the a valve which opens in response to the negative pressure and a second valve which opens in response to the conduit pressure. In the system a first prescribed level and the second prescribed level are set and two pressure switches are provided for generating output at the levels. A failure occurring in the air pump and the valve is detected based on operation of the air pump and the output of the pressure detectors. Alternatively, the failure is detected by changing the timing of the termination of the air pump and closing of the second valve while using one switch and the second prescribed level. The system is simple in configuration.

Failure detection system of exhaust secondary air supply system of

A system for controlling an idle speed of an internal combustion engine having an electrically heated catalytic converter which is heated up when current is supplied from an alternator driven by the engine. In the engine idle control, a basic value of a desired idle engine speed is determined with respect to the engine coolant temperature in the same manner as the prior art. However, an augmentative correction amount of the desired idle engine speed is determined with respect to the exhaust system ambient temperature. More specifically, the desired idle engine speed is increased in response to the heating of the catalytic converter so as to prevent the alternator from generating electric power insufficient for heating up the catalytic converter.

Idle speed control system of internal combustion engine

A system and method for detecting a failure occurring in an exhaust secondary air supply system of an internal combustion engine. A conduit is connected to the exhaust pipe to supply secondary air to the exhaust pipe to promote oxidization of the emissions in the exhaust gases. A valve is provided in the conduit for opening/closing it. The failure of the valve is detected by operating the air pump to supply the air in the conduit, while closing the conduit by the valve. The air/fuel ratio is detected by an oxygen sensor installed downstream of the conduit to be compared with a desired air/fuel ratio. If the detected air/fuel ratio is leaner than a desired air/fuel ratio, the air flows to the exhaust pipe so that the valve is considered to be stuck to open. Alternatively, a pump current is detected and is compared with a reference value indicative of the current at no air flow. If the detected current is less than the reference value, the valve is considered to be in failure. Moreover, the movement of a valve member is sensed to detect whether the valve is stuck to close.

A current control system of an electrically heated catalytic converter installed in the exhaust system of an internal combustion engine. In the engine, fuel metering is controlled by correcting a basic quantity of fuel injection by correction factors. The correction factors are grouped into the factors for increasing the fuel injection quantity at engine warmup and other factors. Therefore, the total value of the factors for increasing the fuel injection quantity at engine warmup are compared with a predetermined value, and if the total value exceeds the predetermined value, the current supply to the heater is inhibited. Alternatively, the cranking time is compared with a predetermined value and if it exceeds the predetermined value, the current supply is inhibited. Since the quantity of fuel injection is increased in these situations, unburned emissions will accordingly be increase. With the arrangement, the exhaust temperature is prevented from rising excessively and the catalytic converter is prevented from being degraded or damaged.

Current supply control system of electrically heated catalytic converter

In an evaporative fuel control system in an internal combustion engine, a purge gas concentration is estimated by a purge gas concentration estimating device based on an air-fuel ratio correcting factor provided when a purge control valve is in its opened state and an air-fuel ratio correcting factor provided when the purge control valve is in its closed state. A lower limit value of an air-fuel ratio correcting factor, set by an air-fuel ratio correcting factor setting device, is determined by an air-fuel ratio correcting factor limit value setting device in accordance with the purge gas concentration estimated by the purge gas concentration estimating device. Thus, the lower limit value of the air-fuel ratio correcting factor can be varied depending upon the concentration of the purge gas, thereby setting an air-fuel ratio control range corresponding to the concentration of the purge gas.

Evaporative fuel control system in internal combustion engine

An evaporated fuel control system in internal combustion engines includes a canister filled with an adsorbent for adsorbing an evaporated fuel in a fuel tank, a purge amount control device provided in the middle of a purge passage connecting an intake passage and the canister, and a fuel supply device. The purge flow rate from the start of purging is integrated, and the purge amount is reduced to a larger extent in response to a purge amount integration value becoming smaller. This improves the nature of an exhaust gas immediately after the start of purging and the like.

Evaporated fuel control system in internal combustion engine

An evaporative emission control system for an internal combustion engine controls purging of evaporative fuel into the intake pipe of the engine. A first control valve is arranged in a communication passage communicating between a charcoal canister and the intake pipe, for supplying the evaporative fuel to the engine at a flow rate dependent on load on the engine. A second control valve is arranged in a bypass passage bypassing the first control valve for supplying the evaporative fuel to the engine at a predetermined flow rate. When a temperature of the engine is below a predetermined value, the first control valve is closed and at the same time the second control valve is made open, to thereby supply the evaporative fuel to the engine at the predetermined i.e. small flow rate. For a predetermined time period after the engine has been warmed up, the first and second control valves are controlled in the same manner. When the engine is idling as well, the same control of the two valves is carried out.

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Wako, Japan

Hiroaki Muramatsu