Abstract: The invention provides an arrangement for detecting ionization in the combustion chamber of a combustion motor where the fuel self-ignites by means of compression, as well as associated measurement device and calibration devices. A measurement tip extends substantially down into a main combustion chamber, which provides access to the portion of the combustion chamber where combustion first starts. The measurement device has a simple construction with good thermal conductivity. Using the calibration device according to the invention, the performance of the measurement device can be optimized from the point of view of control in different combustion motors in which the characteristic ion stream signal for each type of motor can be correlated against pressure data from combustion and used to calibrate the motor.

Abstract: A motorcycle having a system for combustion knock control. The motorcycle includes a spark generating circuit having a spark plug. The spark generating circuit produces a spark across a spark gap of the spark plug in response to a sparking signal. The motorcycle further includes an ion signal circuit that provides an ion signal indicative of an ion current being generated across the spark gap, and an analysis module electrically connected to the ion signal circuit and the spark generating circuit. The analysis module generates the sparking signal in a timed sequence, receives the ion signal from the ion signal generating circuit, measures a knock intensity within the ion signal, and modifies the timing sequence when knock is present.

Abstract: An ignition system with an ion current detecting circuit has an ignition circuit and an ion current detecting circuit. The ignition circuit has an ignition coil that has relatively low inductance about less than 10 henries (H), and a driving circuit for a multi-spark ignition sequence. The ion current detecting circuit detects a second harmonic component of the knock. The components of the system are designed so that a resonance frequency of an ion current path substantially coincide with the second harmonic frequency, and so that a Q-value of the ion current path is greater than 1. As a result, it is possible to improve a knock detecting accuracy.

Abstract: There is provided an improved method of detecting an occurrence of a knock in an internal combustion engine by detecting an ionic current flowing in a cylinder of the engine from initiation of combustion therein and judging a knock component overlapping the ionic current based on a judging level, the method including the steps of: detecting a peak value of the ionic current; and relatively correcting at least one of the judging level and the knock component based on the peak value thus detected so as to make more difficult a judgment of whether the knock occurs or not as the detected peak value increases.

Abstract: A knock control apparatus for an internal combustion engine includes a knock detector for extracting a vibration component superposed on an ion current, and waveform shaping it at a predetermined threshold value to generate a train of knock pulses (Kp) of which the number of pulses indicates a knock intensity of a knock generated in the internal combustion engine, and an engine control unit for counting the number of knock pulses (npn) in the knock pulse train (Kp) output from the knock detector. The engine control unit judges, based on the number of knock pulses (npn), whether or not a knock is occurring. The engine control unit performs a peak hold of the number of knock pulses to calculate the knock judgement threshold value (BGL) by multiplying the number of pulses by (&agr;). Thus, precision in knock judgement is improved by performing knock judgement based on a maximum value (MAX) of the number of knock pulses (npn).

Abstract: A misfire detecting apparatus for an internal combustion engine detects only an ion current due to combustion of an air/fuel mixture regardless of a leakage current when combustion: takes place normally.

Abstract: A motorcycle having a system for combustion knock control. The motorcycle includes a spark generating circuit having a spark plug. The spark generating circuit produces a spark across a spark gap of the spark plug in response to a sparking signal. The motorcycle further includes an ion signal circuit that provides an ion signal indicative of an ion current being generated across the spark gap, and an analysis module electrically connected to the ion signal circuit and the spark generating circuit. The analysis module generates the sparking signal in a timed sequence, receives the ion signal from the ion signal generating circuit, measures a knock intensity within the ion signal, and modifies the timing sequence when knock is present.

Abstract: To obtain a knock detection apparatus which may obtain a good knock pulse S/N even if an ionic current generation amount is changed by the change of a kind of fuel or plugs, a knock detection apparatus for detecting a knock generated, in an internal combustion engine, in which a vibratory component superimposed on an ionic current generated by combustion of fuel is extracted, the component that is equal to or more than a knock detection threshold value is shaped in waveform into a pulse waveform, a knock strength is calculated through counting and calculation process of the number of pulses of the pulse waveform by an engine controlling unit, an ignition timing is controlled on the basis of the knock strength, comprises a knock detection threshold value adjusting unit for changing the knock detection threshold value on the basis of information of an ionic current.

Abstract: A device for detecting the knocking of an internal combustion engine, which maintains the background level at an optimum value irrespective of the knocking level, and features improved reliability by preventing the erroneous detection of noise or knocking when the knocking level is shifted. The device includes a counter 12 for operating signals N of the knocking level from the ionic current, an averaging circuit 13A for operating an average knocking level AVE, a circuit 14A for operating a background level BGLA by using an offset value, a comparator 15 for judging the knocking by comparing the signals of the knocking level with the background level, a circuit 16 for judging the average knocking level that lies in a predetermined region, and a circuit 17 for correcting the offset value depending on the result of judging the predetermined region, wherein the offset value is corrected toward a direction to cancel the increment or the decrement of the average knocking level depending on the predetermined region.

Abstract: An apparatus for detecting a pre-ignition combustion condition in an internal combustion engine. An ion sensing circuit measures an ion current during the ignition coil charging time. An ion current level above a predetermined reference level indicates pre-ignition combustion. A powertrain control module is responsive to a pre-ignition signal for discontinuing delivery of fuel to the cylinder in which the ion current was measured.

Abstract: A method is provided for determining the ion component following a combustion process in a self-igniting internal combustion engine. At least two electrodes are located inside at least one cylinder, to which electrodes an electrical voltage can be applied, with the voltage being an AC voltage or having an AC voltage component.

Abstract: The present invention relates to a method for detecting knocking combustion during the operation of an internal combustion engine with a device for measuring the ionic current, in which the raw ionic current signal or the evaluated value of the knocking intensity are normalized, which enables the value of the knocking intensity to be reliably compared with a threshold value.

Abstract: A failure of a detecting circuit such as an ion current detecting circuit for detecting a combustion condition of an engine can be diagnosed at a stage for detecting a combustion condition by a combustion condition detecting apparatus equipped with a malfunction diagnosing apparatus. The engine combustion condition detecting apparatus equipped with the malfunction diagnosing apparatus is arranged by a sensing circuit for sensing an ion current flowing through a combustion chamber, a misfire judging means for judging misfire occurred in the engine in response to the detection signal derived from the sensing circuit, and a malfunction judging means for judging malfunction of the sensing circuit.

Abstract: To provide a combustion condition detecting apparatus for an internal combustion engine, which may well detect the combustion conditions such as discrimination of a combustion cylinder and knock generating condition and may reduce a circuit scale therefor, there are provided an ignition coil 21 provided for each cylinder; an ignition plug 20 for discharging by the application of the ignition high tension voltage to ignite mixture within the cylinder; a bias circuit 1 provided for each cylinder for applying a bias voltage to the ignition plug 20; an ionic current detection circuit 2 provided for each cylinder for detecting as an ionic current detection signal an ionic current 6 generated in the cylinder that is immediately after the combustion of the mixture; a knock signal processing circuit 4 provided one for a combination of a plurality of cylinders that are every two or more cylinders in ignition order on the basis of a sum of the ionic current detection signals; and an ECU 5 for detecting the combustion c

Abstract: A knock suppression control apparatus for an internal combustion engine which can avoid erroneous knock detection and hence the erroneous knock suppression control, to thereby ensure knock suppression control with high reliability.

Abstract: A device for controlling knocking of an internal combustion engine featuring improved reliability by preventing signals of the knocking level from being erroneously detected as those of the noise level. The device detects an ionic current flowing through a spark plug, counts a signal of the knocking level from the ionic current, establishes an average knocking level from the signals of the knocking level and determines a background level from the average knocking level. A comparator judges the knocking state by comparing the signal of the knocking level with the background level. The device calculates the control quantity of the engine based on the operation conditions and the result of judgement of knocking. The device further judges a transient state and decreases the average knocking level depending upon a transience judgment signal in order to maintain a background level in a transient state at an optimum value.

Abstract: A device for detecting the misfire in an internal combustion engine which features improved reliability for judging the misfire in all operation regions by using either the revolution data or the ionic current depending upon the operation region.

Abstract: There is provided an improved method of detecting an occurrence of a knock in an internal combustion engine by detecting an ionic current flowing in a cylinder of the engine from initiation of combustion therein and judging a knock component overlapping the ionic current based on a judging level, the method including the steps of: detecting a peak value of the ionic current; and relatively correcting at least one of the judging level and the knock component based on the peak value thus detected so as to make more difficult a judgment of whether the knock occurs or not as the detected peak value increases.

Abstract: A combustion state detecting apparatus for an internal combustion engine is imparted with facility for determining discriminatively the causes for non-occurrence of combustion.

Abstract: Only predetermined frequency components included in an ion current flowing between an ignition plug and the ground are extracted from the ion current by means of a low pass filter and a high pass filter as a knock detection signal, that is, a signal used for knock detection. This knock detection signal is then subjected to A/D-conversion in an A/D-converter to generate A/D-converted values which are subsequently supplied to a processing unit employed in a digital signal processor. In the processing unit, the A/D-converted values are subjected to a discrete Fourier transform (DFT) frequency analysis. Knock determination based on data obtained from the DFT frequency analysis results in information indicating the operating state of the internal combustion engine.

Abstract: A method and an apparatus for detecting knocking combustion in an internal combustion engine, by evaluating the ionic current signal sensed in the combustion chamber, is especially adapted to correct or compensate the ionic current signal for longterm variations arising therein, for example due to variations in the composition of the fuel as a result of contamination with metallic components or the like. Thereby, erroneous knock recognition is prevented. To achieve this, a frequency-filtered time-sampled knocking component integral of the ionic current signal generated in the present combustion cycle is multiplied by a correction value determined from at least one integral value of the ionic current signal generated during at least one prior combustion cycle.

Abstract: The present invention relates to a method for determining the running smoothness of an Otto spark ignition engine by measuring the ionic current (I) in at least one combustion chamber of the Otto spark ignition engine. Once the spark plug has fired, a measuring voltage is applied to the spark plug, inducing the ionic current (I). Following each ionic current measurement, initially an active, average ionic-current value (IM) is defined, and a running-smoothness value (L) is subsequently determined from a reference value and the ionic-current average value (IM).

Abstract: A combustion state detecting device for an internal combustion engine enables diverse combustion state detection by obtaining a plurality of currents analogous to an ion current. The combustion state detecting device includes a bias circuit 6 that applies an ion current detection voltage to an ignition plug 3 disposed in a cylinder of the internal combustion engine, an ion current signal distributor circuit 20 made up of a current mirror circuit for detecting the ion current on the basis of a voltage from the bias circuit, and current-voltage converter circuits 21 and 22, to thereby produce a plurality of currents analogous to the ion current by the ion current signal distributor circuit.

Abstract: A method for detecting flow-reducing changes in an exhaust-gas catalyst body is provided. The method includes measuring the ion-current signal from an ion-current probe in an internal combustion engine and monitoring the signal to determine whether its signal strength for a particular operating cycle falls below a minimum strength which can be specified as a function of the engine operating state. The method also include providing warning information to the control system when such an event occurs. The method further includes a variety of embodiments used to determine whether the ion current signal falls below a minimum strength.

Abstract: For a purpose of improving detecting performance toward knocking in small and middle intensity which must be detected as a top priority to conduct regulation of ignition timing, a device is provided to vary an output gain of an alternating component included in an ion current in accordance with ion current quantity. An ion current detector to detect the ion current to be generated surrounding an ignition plug just after mixed gas inside a cylinder has been ignited with a spark discharge having occurred at the ignition plug due to a voltage generated by an ignition coil, comprises a bias voltage generating part to generate a high voltage for an ion current detection to be applied to the ignition plug via the ignition coil, an ion current-to-voltage conversion part to convert an ion current having flowed between electrodes of the ignition plug by the high voltage into a voltage, and a knock signal generator to extract and amplify a frequency band resembling knocks on the basis of voltage conversion effect.

Abstract: To obtain a combustion state detecting device in which a detection range is optimized to thereby make it possible to improve the S/N ratio, thereby making it possible to enhance the accuracy in detection of the combustion state of the internal combustion engine, in particular, the accuracy in knock detection.

Abstract: A biasing circuit for an ion current measurement system draws power from a primary side of the ignition coil, and applies a positive polarity bias voltage to a low voltage side of a secondary winding of the ignition coil. The biasing circuit includes a silicon-controlled rectifier (SCR) which has an on state for carrying spark current during a spark interval of operation, and further includes an off state which prevents the stored biasing voltage on a capacitor from being shunted to ground, thereby allowing ion current sensing through the low voltage side of the secondary winding. The low on-state voltage drop of the SCR during conduction of spark current minimizes losses of spark energy.

Abstract: A device for detecting the knocking of an internal combustion engine maintaining a favorable knock-detecting state even when a noise component having a small amplitude and lasting long is superposed on an ionic current detection signal. The device comprises a means 1 for detecting the ionic current i that flows through a spark plug 8, a filter 2 means for picking up knock signals Ki from the ionic current, a means 22 for judging the knocking state based on the knock signals, a means 11 for operating a first integrated value Km1 of the knock signals, a means 21 for setting a basic threshold value TH based on the first integrated value, a means 12 for operating a second integrated value Km2 by integrating only those knock signals having amplitudes larger than a lower-limit level among the knock signals, and a means 32 for setting the basic threshold value as the lower-limit level, wherein the occurrence of knocking is judged based on the second integrated value.