Nippondenso Co., Ltd.

Yasuhito Takasu

Toshiharu Iwata

Katsuharu Hosoe

Shingo Inoue

Hiroshi Ikeda

Masaaki Nakayama

Hiroshi Haraguchi

Seiji Morino

Yasuo Mukai

Daiji Isobe

Kozo Takamura

Kouichi Shimizu

Yasutoshi Baba

Taro Tabata

Minoru Hotta

Hideki Morishima

Masato Somiya

Isamu Nomura

A catalytic converter deterioration detecting system for an engine derives a low-frequency component in an output of a downstream-side oxygen sensor provided downstream of a catalytic converter. The system detects deterioration of the catalytic converter based on the low-frequency component, such as, an amplitude of the low-frequency component or a period of the low-frequency component. For higher detection accuracy, an amplitude of a high-frequency component in the output of the downstream-side oxygen sensor is additionally used for detecting deterioration of the catalytic converter. Specifically, the system determines that the catalytic converter is deteriorated when the low-frequency amplitude is smaller than a given value and the high-frequency amplitude is greater than a given value.

Catalytic converter deterioration detecting system for engine

An apparatus for detecting a rough road running condition of a combustion engine car comprising means for calculating change values of an output rotational speed of the engine, means for calculating an instability of the measured change values, and means for judging the car to be on a rough road when the calculated instability is more than a predetermined amount.

Apparatus and method for detecting a road surface condition of a car

In a misfire detecting apparatus for a multicylinder internal combustion engine, a rotational signal outputting unit outputs a rotary signal at every predetermined rotary angle, and a tentative misfire decision unit tentatively decides, on the basis of the rotary signal, whether or not misfire has occurred in each cylinders of the engine. A tentative misfire number counting unit counts the number of tentative misfires decided for respective cylinders, and a counting result storage unit stores the counting results. After a given number of tentative misfire decisions have been made, it is decided that misfire has actually occurred, only if the counting result, for a part of the cylinders, among the counting results for respective cylinders stored in the counting result storage unit is larger than a predetermined number.

Misfire detecting apparatus for multicylinder internal combustion engines

An engine speed control apparatus comprises: a first detector for detecting an engine speed; a second detector for detecting idling condition of the engine; a first setting circuit responsive to the first detector for setting a target engine speed; a second setting circuit responsive to the first detector for setting target ignition timing; a first integrator for obtaining a first integrated value of deviation of the engine speed from the target engine speed; a second integrator for obtaining a second integrated value of deviation of ignition timing from the target ignition timing; a third detector for detecting a flow rate of intake air; a determining circuit for determining a value of a predetermined state variable, presenting an internal condition of the engine according to the engine speed, the ignition timing, the flow rate of intake air; a third setting circuit for determining the flow rate of intake air supplied to the engine according to the value of the predetermined state variable, the first and second integrated values; and a fourth setting circuit for setting the ignition timing according to the value of the predetermined state variable, and the first and second integrations.

Engine speed control apparatus

A knock control system which detects a knock occurring in an engine, a knock detector for detecting the occurrence of the knock in accordance with a knock sensor signal produced by the sensor, a first adjuster for adjusting knock control factors so as to suppress the knock on the basis of a detected signal from the knock detector, a converter for converting the knock sensor signal so as to make the frequency distribution of the knock sensor signal equal to an exponential distribution, a standard deviation calculator for calculating the standard deviation of the exponential distribution, and a second adjuster for adjusting knock control factors so that this standard deviation reaches a predetermined value, whereby the standard deviation of the frequency distribution of the knock sensor signal can be easily detected, thus making it possible to reduce the load on the electronic control system and prevent the knock detection precision from being reduced by the characteristic change of the knock sensor, engine.

Knock control system for engine

An ignition system of multispark type having an ignitability superior to that of a combination an ignition system of capacitor discharge type and a multispark system is disclosed. A first control signal is generated for turning on a first switching device a predetermined time before an ignition timing to store energy in an energy storage coil and turning off the first switching device at the ignition timing. A multispark control signal is generated for turning on a second switching device from the ignition timing and turning on and off the first and second switching devices alternately for a predetermined spark period. A second control signal is generated for turning on the first switching device upon the turning off of the second switching device to store energy in the energy storage coil and then turning off the first switching device to charge a capacitor with the energy stored in the energy storage coil.

Ignition system of multispark type

The ignition timing of an internal combustion engine is controlled to an optimum by compensating for engine knock. A microcomputer includes a memory for storing steady-state and transient-state ignition timing variables which are derived as a function of an operating condition of the engine. If engine knock occurs during a steady running state, the stored steady-state ignition timing variable is trimmed and if engine knock occurs during a transient state, the stored transient-state ignition timing variable is trimmed. Ignition is caused to occur in response to the stored value of the trimmed steady-state or transient-state ignition variable according to the detected engine condition.

Ignition timing control for compensating knock in both steady-state and

Ignition timing for an internal combustion engine is controlled by subtracting a retard correction amount from a basic ignition timing. When engine knocking is detected, the retard correction amount is retarded from the basic ignition timing, but not so that the controlled timing drops below a predetermined limit. If knocking is not detected, the retard correction amount is advanced to thereby control the ignition timing towards, but not exceeding, a knocking limit.

Method and apparatus for ignition timing control of internal combustion

A method for controlling the ignition timing of internal combustion engines by reducing the amount of correction of ignition timing with each change of direction of the correction. This increases the speed of approach to the approximate optimum ignition timing yet minimizes variation of ignition timing near the optimum state.

Ignition timing control for internal combustion engines

Engine operating parameters are detected to set a basic ignition timing, and this basic ignition timing is forcibly changed to effect feedback control in which an engine output parameter is detected for finding an optimum combination of ignition timings of the individual cylinders. The ignition timing for all the cylinders is uniformly changed for a predetermined period of time so that engine output increases, and then ignition timing is individually controlled for each of the cylinders so that ignition timing of each cylinder is optimum. The engine is operated with a plurality of different ignition timing combinations, where the number of the combinations equals the number of the cylinders plus one. The average value of various ignition timings of the plurality of combinations is calculated, and the combination giving the lowest engine output parameter is detected. A new ignition timing combination is set so that engine output increases, and the combination giving the lowest engine output parameter is replaced by the new combination so that a new set of the plurality of ignition timing combinations is provided. In this way the ignition timing combination is renewed successively for finding the optimum ignition timing combination.

Method and apparatus for controlling ignition timing in a multicylinder

Engine parameters are detected to set a basic ignition timing, and this basic ignition timing is forcibly changed to effect feedback control in which engine output is detected for finding an optimum combination of ignition timings of the individual cylinders. Engine is operated with a plurality of different ignition timing combinations, where the number of the combinations equals the number of the cylinders added by one. The engine is further operated with one of the ignition timing combinations so that the engine is operated twice with an identical ignition timing combination. As a result engine output change caused by factors other than ignition timing change is detected. Thus, one of a plurality of ignition timing combinations, which gives the lowest engine speed is found and is replaced with a new ignition timing combination with which the engine produces higher output. The replacement is carried out selectively in accordance with the variation rate of the engine output data. An average value of various ignition timing combinations is used to renew the same. In this way the ignition timing combination is renewed succesively for finding the optimum ignition timing combination.

Engine parameters are detected to set a basic ignition timing, and this basic ignition timing is forcibly changed to effect feedback control in which engine output is detected for finding an optimum combination of ignition timings of the individual cylinders. Engine is operated with a plurality of different ignition timing combinations, where the number of the combinations equals the number of the cylinders added by one. The engine is further operated with one of the ignition timing combination so that the engine is operated twice with an identical ignition timing combination. As a result engine output change caused by factors other than ignition timing change is detected. Thus, one of a plurality of ignition timing combinations, which gives the lowest engine speed only because of the change in ignition timing is found and is replaced with a new ignition timing combination with which the engine produces higher output. The replacement is carried out selectively in accordance with the variation in engine output data resulted from various ignition timing combinations. An average value of various ignition timing combinations is used to renew the same. In this way the ignition timing combination is renewed successively for finding the optimum ignition timing combination.

Engine parameters are detected to set a basic ignition timing, and this basic ignition timing is forcibly changed to effect feedback control in which engine output is detected for finding an optimum ignition timing. Engine is operated with a plurality of different ignition timings, where the number of the ignition timings is at least two, and engine output data for each ignition timing is measured to find which ignition timing causes a higher engine output. Thus, one of the plurality of ignition timings, which gives the lowest engine speed is replaced with a new ignition timing with which the engine produces higher output. The new ignition timing is computed in such a manner that the new ignition timing is located at a point opposite to the ignition timing giving the lowest engine output with respect to an average ignition timing, while the difference between the average value and the new ignition timing equals a multiple of the difference between the ignition timing giving the lowest engine speed and the average value. In this way the ignition timing is renewed successively for finding the optimum ignition timing.

Method and apparatus for controlling ignition timing in an internal

A method in a multicylinder engine, for obtaining the single combination of ignition timings for the individual cylinders producing the maximum engine speed. A group of combinations of ignition timings is selected, then the engine is successively operated by each combination. The combination producing the lowest engine speed is determined and replaced by a new combination of ignition timings capable of increasing the engine speed. The new combination is calculated by use of a predetermined formula. This procedure is repeated to obtain the single combination of ignition timings producing the maximum engine speed.

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Toyohashi, Japan

Yasuhito Takasu