Abstract: A conversion efficiency of a catalyst is estimated by a correlation function concerning output signals of upper and down stream side air fuel ratio sensors. The conversion efficiency is measured by comparing the correlation function and a complement value of the correlation function with a comparing standard value.

Abstract: A system for reducing knock in an internal combustion engine is disclosed and includes a vibration detector which detects engine vibration and generates an output signal representative of the magnitude of the engine vibration over a predetermined frequency spectrum. The vibration output signal multiplied by a first weight factor is integrated over a lower portion of the frequency spectrum to obtain a first value while the vibration signal multiplied by a second weight factor is integrated over a higher portion of the frequency spectrum to obtain a second value. The first value is compared with a first threshold value and, when the first value exceeds the first threshold, the system generates a fuel control output signal to increase the fuel supplied to the engine to reduce engine knock.

Abstract: A detector for detecting a physical quantity as a quantity of electricity has a detection portion, a portion for stimulating the detection portion and a signal processing portion, wherein a calibrating signal is supplied from the signal processing portion to the detection portion via the stimulating portion so as to measure a specific response of the detection portion whereby a self-calibration and a correction of the characteristics are performed in accordance with the amount of the change in the response.

Abstract: An engine control apparatus for shifting an ignition timing signal to an ignition coil (48) so that the engine produces optimum torque generates a pseudo random signal (26) which is preferably an M series signal and applies the pseudo random signal to a parameter of the engine having a noise frequency component such as the engine rotational speed y(t). The M series signal is a signal having a impulse type self correlation function. A mutual correlation function of the number of revolutions of the internal combustion engine and of the M series signal is computed (30-44) and an optimum ignition advance angle is supplied to an adder (46). The adder (46) combines the optimized signal ignition advance angle with a basic ignition timing signal (.theta..sub.advB) to provide an ignition timing signal (.theta.ig) to the ignition coil (48).

Abstract: The present specification discloses a diagnosis system and an optimum control unit for an internal combustion engine. The basic concept of the present invention resides in that a random retrieved signal of which auto correlation function is an impulse shape is superposed on a signal of an internal combustion engine, said superposed signal is used to measure a change of an operation state of the internal combustion engine, and an optimum direction of a control value is detected by a correlation between said measured value and retrieved signal.

Abstract: The present specification discloses a diagnosis system and an optimum control unit for an internal combustion engine. The basic concept of the present invention resides in that a random retrieved signal of which auto correlation function is an impulse shape is superposed on a signal of an internal combustion engine, said superposed signal is used to measure a change of an operation state of the internal combustion engine, and an optimum direction of a control value is detected by a correlation between said measured value and retrieved signal.

Abstract: An engine controller equipped with a device for judging occurrence of knocking of the engine, having a sensor for sampling a vibration based on an internal pressure vibration arisen in a cylinder of the engine and a knocking detecting means for judging the occurrence of the knocking by obtaining at least two frequencies contained in an output from the sensor, obtaining a knocking judgement index from two vibration power factors corresponding to the two frequencies and comparing the knocking judgement index with a threshold value. As being judged from the knocking judgement index, the occurrence of the knocking is accurately detected when the background vibration is great at the time of the high load high speed operation.

Abstract: A control system for the internal combustion engine is disclosed, in which the operating conditions (such as vehicle speed) and the control conditions (such as throttle opening degree) of the operating elements of the internal combustion engine are used to determine a resistance index (such as an equivalent gradient) for specifying the driving force corresponding to the operating conditions under the prevailing load conditions. Further, this resistance index data is accumulated, so that the operating elements are controlled on the basis of a target operating condition and a corresponding resistance index.

Abstract: A throttle control apparatus of an internal combustion engine comprises an accelerator opening detector, an engine revolution speed detector, a throttle actuator and a control unit constructed so as to generate and output, to the throttle actuator, a throttle driving signal for operating the throttle valve according to a throttle opening pattern determined on the basis of an accelerator opening, an accelerator opening speed and engine revolution speed, the throttle opening pattern includes a first target opening to which throttle valve is opened upon a rapid accelerator operation and which is determined according to an accelerator depression quantity, an accelerator depression speed and an engine revolution speed, a second target opening to which said throttle valve is opened after a predetermined time lapsed from the starting of the rapid accelerator depression and which is determined according to an accelerator depression quantity, an accelerator depression speed and an engine revolution speed.

Abstract: A gas detecting apparatus incorporates a number of gas detecting elements which react with a variety of gases and exhibit gas sensitivities differing from one another in dependence on the gas species. The detection patterns obtained by quantitizing the detection outputs of the gas detecting elements are compared with a plurality of standard patterns prepared previously for assumed combinations of gas species and concentrations thereof. On the basis of the standard pattern which is same or most similar to the detection pattern, the gas species is identified.

Abstract: A gas detecting apparatus is disclosed in which detection outputs from a plurality of semiconductor gas detecting elements different in gas detection characteristic from each other and previously-obtained characteristic values of the semiconductor gas detecting elements for a mixed gas are subjected to operational processing to detect one or more specified constituent gases contained in the mixed gas, and in which when the specified constituent gas is detected, the detection information is announced by some means, and also the supply of gas is stopped or a supply gas is diluted.

Abstract: A gas detector with a layer of gas sensing material comprising an oxide semiconductor, wherein at least one coating layer each of a p-type oxide semiconductor and an n-type oxide semiconductor is provided in a multi-layer arrangement on the surface of said layer of gas sensing material that contacts the gas. The gas detector can selectively identify only specific gases.