Honda Motor Co., Ltd.

Eisaku Gosyo

Toshinori Tsukamoto

Atsushi Izumiura

Hideyuki Oki

Daisuke Sato

Hiroaki Nishino

Kiyoshi Saito

Takashi Yamaguchi

Hidetaka Maki

Jun Iida

Yoshitaka Takasuka

Hirofumi Hara

Masaki Tsuda

Tomohiro Yamagami

Yasuaki Itou

Shinza Goto

An exhaust gas purifying apparatus for an internal combustion engine having a particulate filter provided in an exhaust system of the engine. Regeneration control is performed of burning particulates accumulated in the particulate filter. An oxygen concentration in exhaust gases flowing into the particulate filter is detected, and a flow rate of oxygen flowing into the particulate filter is calculated according to the detected oxygen concentration. An inflowing oxygen amount is calculated by integrating the oxygen flow rate when performing regeneration control. It is determined that an abnormality has occurred if the inflowing oxygen amount at a time when regeneration control ends is equal to or less than a predetermined amount.

Exhaust gas purifying apparatus for internal combustion engine

A particulate filter is provided in an exhaust system of the engine. Parameter values correlated with a flow amount of exhaust gas of the engine are determined, and differential pressure between upstream and downstream sides of the particulate filter is determined. The ratio of a variation rate of the parameter values correlated with the exhaust flow amount to a variation rate of the differential pressure is compared with a predetermined threshold value during transitional operation of the engine to determine the state of the particulate filter.

Apparatus for detecting a state of a particulate filter

Deterioration of a catalyst provided in an exhaust system of the engine is determined. Air-fuel ratio sensors are provided in the upstream side and the downstream side of the catalyst. Air-fuel ratio is changed. Based on the sensor outputs in the upstream die and the downstream side of the catalyst, a parameter of a catalyst model representing a state of the catalyst is identified. The parameter is compared with a threshold to determine a state of the catalyst.

Scheme for detecting deterioration of a catalyst in an engine

An abnormality determination apparatus and method for a blow-by gas feedback device, and an engine control unit are provided for improving the accuracy of abnormality determination even when an intake air amount controller is provided in an intake system at a location downstream of a joint of a blow-by gas passage. The blow-by gas feedback device feeds a blow-by gas back to an intake system of an internal combustion engine through a blow-by gas passage connected to the intake system through a joint. The abnormality determination apparatus comprises an intake air amount sensor provided in the intake system at a location upstream of the joint for detecting an intake air amount, an intake air amount controller provided in the intake system at a location downstream of the joint for controlling the intake air amount, and an ECU for determining an abnormality of the blow-by gas feedback device based on the intake air amount detected by the intake air amount sensor after the intake air amount has changed due to the operation of the intake air amount controller.

Abnormality determination apparatus and method for blow-by gas feedback device, and engine control unit

A failure determination system for determining failures of temperature sensors, which is capable of easily and accurately determining failures of the sensors in actual operating temperature ranges thereof, even when the ranges are different from each other. Temperatures detected by exhaust gas temperature sensors are stored as initial temperatures when the engine has stopped. Temperatures detected by the respective sensors after stoppage of the engine are made dimensionless based on the corresponding initial temperatures to thereby calculate dimensionless values. An estimated dimensionless value of a temperature to be detected when each sensor is normal is set in advance as an estimated normal value. Failures of the sensors are determined based on results of comparisons of the dimensionless values with the estimated normal value.

Failure determination system and method for temperature sensors, as well as engine control unit

An apparatus for detecting a failure of a thermostat provided between an engine and a radiator is provided. The thermostat regulates circulation of cooling water between the engine and the radiator. The apparatus comprises a radiator water temperature sensor disposed on the radiator side relative to the thermostat and a controller. The controller performs a process for detecting a failure of the thermostat based on the output of the radiator water temperature sensor when the engine has reached a desired warm condition. In one example, it is determined whether the engine has reached the desired warm condition based on the output of the engine water temperature sensor that is provided in the engine side relative to the thermostat. In another example, it is determined whether the engine had reached the desired warm condition according to whether a vehicle-related process is activated. In yet another example, it is determined whether the engine has reached the desired warm condition based on an estimated value for the engine water temperature.

Apparatus for detecting a failure of a thermostat for an engine

In a malfunction detecting system of an engine cooling apparatus constituted as a radiator having a thermostat opening/closing an inlet pipe and an outlet pipe, a temperature sensor is installed at the radiator to detect a temperature of the coolant flowing through the radiator. In the system, a period of time since the engine starting is measured and is compared with a predetermined value indicative of a period of time until the thermostat presumably opens. Then, the detected coolant temperature is compared with three reference values, when the measured period of time exceeds the predetermined value and it is discriminated that the cooling apparatus, more specifically, the thermostat of the radiator has malfunctioned, when the coolant temperature exceeds a medium one of the reference values. In addition, it is discriminated the apparatus has malfunctioned, if the coolant temperature exceeds the highest reference value, even when the measured period of time does not exceed the predetermined value. Further, the discrimination is reserved, if the coolant temperature exceeds the lowest reference value, but the coolant temperature does not exceed the highest reference value, while it is discriminated that the apparatus is normal, if the coolant temperature does not exceed the lowest reference value. With this, by directly detecting radiator coolant temperature, the malfunction can be detected with high accuracy.

Malfunction detecting system of engine cooling apparatus

An apparatus for determining leakage in an evaporated fuel processing system is provided. The evaporated fuel processing system extends from a fuel tank through a canister to a purge passage through which evaporated fuel from the fuel tank is purged to an intake manifold of an engine. The canister comprises a vent-shut valve that communicates with the atmosphere. The apparatus comprises a pressure sensor for detecting a pressure of the evaporated fuel processing system and a control unit connected to the pressure sensor. The control unit detects a stop of the engine. After the stop of the engine is detected, the control unit closes the vent-shut valve to close the evaporated fuel processing system. The control unit determines whether the evaporated fuel processing system has leakage after the evaporated fuel processing system is closed based on the detected pressure and a predetermined determination value. The control unit prohibits the leakage determination if the detected pressure is not within a predetermined range. Thus, it is prevented that a state occurs where the vent-shut valve does not open due to the pressure of the evaporated fuel processing system when the leakage determination is being performed.

Apparatus for detecting leakage in an evaporated fuel processing system

An apparatus for determining leakage in an evaporated fuel processing system is provided. The evaporated fuel processing system extends from a fuel tank to a purge passage through which evaporated fuel from the fuel tank is purged to an intake manifold of an engine. The apparatus comprises a pressure sensor for detecting a pressure of the evaporated fuel processing system, an atmospheric pressure sensor for detecting an atmospheric pressure, and a control unit connected to the pressure sensor and the atmospheric pressure sensor. The control unit detects a stop of the engine. A determination value used for the leakage determination is corrected according to the atmospheric pressure. The evaporated fuel processing system is closed after the stop of the engine is detected. It is determined whether the evaporated fuel processing system has leakage based on the pressure detected by the pressure sensor and the corrected determination value. Since the determination value is corrected according to the atmospheric pressure, leakage is accurately determined regardless of whether the vehicle is located in highlands or lowlands.

The invention provides a failure diagnosing apparatus having a first sensor for detecting a temperature of cooling water of an engine mounted on a vehicle and a second sensor for detecting a temperature associated with the engine. The apparatus calculates a first difference between a temperature detected by the first sensor at the time when the engine stops in a previous operating cycle and a temperature detected by the first sensor at the time when the engine starts in a current operating cycle is calculated. The apparatus also calculates a second difference between a temperature detected by the second sensor at the time when the engine stops in the previous operating cycle and a temperature detected by the second sensor at the time when the engine starts in the current operating cycle. It is determined whether the first sensor is faulty based on the first difference and the second difference.

Failure diagnosing apparatus for an engine cooling water temperature sensor

In a malfunction detecting system of an engine cooling apparatus constituted as a radiator having a thermostat that opens/closes a communicating passage between the engine and the radiator, estimated coolant temperature is calculated using a thermal load parameter correlated to rise in the coolant temperature after engine starting, whilst an engine standing time period is detected. Then, the detected engine standing time period is compared with a predetermined value and based on a result of comparison, one of preset threshold values including a malfunction discrimination threshold value and a malfunction discrimination execute threshold value is selected. The selected threshold value is then compared with the estimated coolant temperature or a difference between the estimated coolant temperature and the detected coolant temperature, and it is discriminated that the cooling apparatus has malfunctioned, when the estimated coolant temperature or the difference exceeds the malfunction discrimination threshold value. With this, the malfunction can be detected with high accuracy.

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Wako, Japan

Eisaku Gosyo