Abstract: This invention relates to a hybrid vehicle controlling device and method of using the device, in which an engine torque proportion (which is transmitted from an engine to a driving shaft) of a total sum of torque transmitted to the driving shaft is calculated. An allowed surge torque value, which is an upper limit of a surge torque allowed to the engine, is set to a larger value as the engine torque proportion is reduced. Then a predetermined parameter of the engine is changed so that the engine is controlled in a range in which the surge torque of the engine does not go beyond the allowed surge torque value.

Abstract: This invention relates to a hybrid vehicle controlling device and method of using the device, in which an engine torque proportion (which is transmitted from an engine to a driving shaft) of a total sum of torque transmitted to the driving shaft is calculated. An allowed surge torque value, which is an upper limit of a surge torque allowed to the engine, is set to a larger value as the engine torque proportion is reduced. Then a predetermined parameter of the engine is changed so that the engine is controlled in a range in which the surge torque of the engine does not go beyond the allowed surge torque value.

Abstract: Start points of a misfire determining interval in the cylinders of an engine are specified by counting Pos signals starting from the appearance of a Ref signal in a specific cylinder. The Pos signals output from the Ref signal in each cylinder to the start point of the misfire determining interval are also counted as RGPHS after engine startup, and a shift of the misfire determining interval is detected by comparing for example the sum total of RGPHS for all cylinders and the sum total on the immediately preceding occasion. Correction of the misfire determining interval by a learnt value is stopped according to this shift. Preferably, correction of the misfire determining interval by the learnt value is restarted after making all misfire determining intervals the same by correcting for the shift.

Abstract: The air/fuel ratio of an engine is feedback controlled based upon the output of an oxygen sensor. The control includes proportional control and also correction of a control variable for this proportional control according to the actual air/fuel ratio. The period of the output signal of the oxygen sensor during feedback control is measured, a decision value is set corresponding to change in the control variable, and deterioration of the oxygen sensor is determined by comparing the period of the output signal with the decision value. By doing this, change in the control variable is prevented from exerting any influence upon the period of the output signal of the oxygen sensor, and the accuracy of deterioration diagnosis for the oxygen sensor is enhanced.

Abstract: A diagnostic apparatus applicable to diagnosis of engine misfire. A diagnostic result is produced for each of at least two diagnoses related to each other. Only one of the diagnostic results having a higher degree of necessity is retained to indicate a malfunction.

Abstract: A mechanism is provided for outputting reference signals in synchronism with the firing action of the cylinders of a multi cylinder engine. Correction coefficients are calculated for correcting deviations in the periods between the cylinders from the periods of the reference signals which are obtained during the fuel cut off state. The periods of the reference signals for each cylinder are corrected according to these correction coefficients, and the presence or absence of misfiring for each cylinder is determined from the corrected periods. On the one hand the determination of misfiring is prevented when input of external interference to the engine is present, and on the other hand the learning of the correction coefficients is prevented when instability has occurred in the reference signals during the fuel cut off state.

Abstract: A secondary air supply apparatus for an internal combustion engine is provided with an air-fuel ratio sensor disposed upstream of an catalytic converter in an exhaust passage. An outlet port of a secondary air supply conduit is formed upstream of and in the vicinity of the air-fuel ratio sensor. Air discharged from an air pump is supplied to the exhaust passage through the secondary air supply conduit. A control unit diagnoses as to whether or not the air-fuel ratio sensor is activated by checking as to whether a detection signal of the air-fuel ratio sensor is out of a predetermined range or not. Then, the control unit diagnoses as to whether the supply of the secondary air is normal or not on the basis of the detection signal of the air-fuel ratio sensor. Therefore, the diagnosis of the supply of the secondary air is correctly executed.

Abstract: A vehicle engine temperature is detected, and a radiator fan fault warning is given so as to prevent engine overheating when this temperature rises to or above a preset determining value under a predetermined test conditions. Preferably, it is determined that the radiator fan has a fault when a temperature equal to or above this determining value holds for at least a predetermined time. More preferably, this determining value is set low while the vehicle is in motion. By providing these supplementary conditions, incorrect diagnosis of a fault in the radiator fan is prevented.

Abstract: A learning control system for controlling an air fuel ratio an engine employs a slowly updated second learning control variable in addition to a normally updated first learning control variable in order to utilize the learning function sufficiently even when a deviation of the air fuel ratio exceeds the learning range of the first variable. The control system according to an illustrated embodiment of the invention identifies a current engine operating area among a plurality of such areas, in accordance with a sensed engine operating condition, obtains a value of the first learning variable corresponding to the identified operating area, and a value of the second learning variable, determines a learning quantity which is a sum of the first and second learning variables by using the obtained values, and uses this learning quantity for determining a desired fuel supply quantity. The second learning variable is updated slowly whereas the first learning variable is updated in a sensitive and speedy manner.