Abstract: An exhaust gas purifying apparatus for an internal combustion engine including a first filter and a second filter. The first filter traps particulates in exhaust gases from said engine. The second filter is provided for failure detection and disposed downstream of the first filter. The trapping state of the second filter is detected and a filtering capability of the first filter is diagnosed based on the detect trapping state of the first filter.

Abstract: An exhaust gas purifying apparatus for an internal combustion engine, having a filter for trapping particulates in exhaust gases from the engine, is disclosed. A first particulate amount indicates an amount of particulates to be trapped by the filter and is calculated according to an operating condition of the engine. A second particulate amount indicates an amount of particulates trapped by the filter and is calculated according to a temperature of the filter when a filter regeneration of burning the particulates trapped by the filter is performed. The first particulate amount is compared with the second particulate amount, and a failure determination of the filter is performed according to a result of the comparison.

Abstract: An exhaust gas purifying apparatus for an internal combustion engine including a first filter and a second filter. The first filter traps particulates in exhaust gases from said engine. The second filter is provided for failure detection and disposed downstream of the first filter. The trapping state of the second filter is detected and a filtering capability of the first filter is diagnosed based on the detect trapping state of the first filter.

Abstract: 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.

Abstract: 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.

Abstract: An air-fuel ratio control system for an internal combustion engine has an air-fuel ratio sensor arranged in an exhaust passage of the engine for detecting an air-fuel ratio of exhaust gases emitted from a plurality of cylinders. An output from the air-fuel ratio sensor is sampled whenever the engine rotates through a predetermined crank angle, and sampled values of the output from the air-fuel ratio sensor are sequentially stored. An output characteristic of the air-fuel ratio sensor is detected. One of the sampled values of the output from the air-fuel ratio sensor is selected at least depending on the output characteristic of the air-fuel ratio sensor. An air-fuel ratio of a mixture supplied to each of the cylinders is estimated, separately from other ones of the cylinders, based on selected ones of the sampled values of the output from the air-fuel ratio sensor and a model representative of a behavior of the exhaust passage.

Abstract: A fuel injection apparatus for internal combustion engine of this invention applies detection output of a wide-range air/fuel ratio sensor to an observer so as to estimate an air/fuel ratio of individual cylinder and, based on thus estimated air/fuel ratio, obtains an air/fuel ratio correction coefficient for individual cylinder and correctively controls the fuel injection amount for individual cylinder with the air/fuel ratio correction coefficient for individual cylinder. While the estimation processing of the observer is always continued, the air/fuel ratio correction coefficient for individual cylinder is automatically adjusted, for example, when the estimated air/fuel ratio becomes an abnormal value, according to operational condition of the internal combustion engine, and the like, thereby securing the stability in the corrective control and preventing the emission from deteriorating.

Abstract: A system for detecting a combustion knock occurred in a combustion chamber of an internal combustion engine. The system includes a sensor for detecting vibration generated in the engine. Sensor output within a range of crankshaft angles during which no combustion occurs is averaged and amplified to determine a reference noise level. Sensor output within another range of crankshaft angles during which combustion occurs is compared with the reference noise level and if the sensor output exceeds the reference noise level, a combustion knock is determined to be present. In the system, a traction control system (TCS) is incorporated in which the engine output torque is reduced when the driven wheel of the vehicle on which the engine is mounted is great. The reference noise level is enlarged when the TCS operates such that the mechanical vibration increased by the sudden change in the torque due to the TCS operation is prevented from being erroneously detected as the combustion knock.

Abstract: A system for controlling combustion knock, if occurring, in an engine by suppressing it by retarding ignition timing. The engine is equipped with traction control for preventing the driven wheel of the vehicle on which the engine is mounted from slipping. In the system, if the traction control is in process, by leaning out a mixture to be supplied to the engine at a high engine speed region, the knock control is discontinued so as to prevent the exhaust gas temperature from rising excessively and so as not to degrade a catalyst installed in the exhaust system and exhaust emission. The knock control is suspended for a period even after the supply of the lean mixture has ceased.

Abstract: An ignition timing control system for an internal combustion engine includes an ECU which calculates a knocking correction value in response to an output from a knocking sensor, and an advance limit value in response to engine operating conditions. The ECU operates to limit correction of the ignition timing of the engine in an advancing direction, beyond the advance limit value when the knocking correction value exceeds the advance limit value. The ECU cancels the advance correction limitation when at least one of conditions of high coolant temperature, high intake air temperature, low coolant temperature, and low rotational speed is satisfied.

Abstract: An ignition timing control system for an internal combustion engine includes an ECU which calculates a knocking correction value in response to an output from a knocking sensor, and an advance limit value in response to engine operating conditions. The ECU operates to limit correction of the ignition timing of the engine in an advancing direction, beyond the advance limit value when the knocking correction value exceeds the advance limit value. The ECU carries out the advance correction limitation when the engine load exceeds a first predetermined value. Further, the ECU sets a predetermined reference value more advanced than the advance limit value, in response to engine operating conditions.