Abstract: A determination is made as to whether or not knocking is actually occurring inside a combustion chamber (5), and on the basis of the knocking detection result, a knocking-correlated parameter (octane number, alcohol concentration, compression ratio of the engine), which is a parameter having a correlation with knocking, is estimated. A knocking occurrence timing in the combustion chamber (5) is then predicted on the basis of the estimated knocking-correlated parameter. A knocking limit ignition timing, which is the ignition timing furthest toward the advanced side at which knocking does not occur, is calculated on the basis of the predicted knocking occurrence timing, and an ignition device (11) is controlled to perform spark ignition at the knocking limit ignition timing.

Abstract: A valve performance controller for use in an engine that performs ignition timing retardation control to prevent knocking. The controller variably controls valve performance of an intake valve in accordance with an operation state of the engine. The controller corrects a control target so that the compression end temperature of a combustion chamber decreases when a retardation amount of the ignition timing obtained through the retardation control is greater than a predetermined value. The correction is performed only when the engine performance degradation that would occur when the ignition timing is retarded in a state in which the control target is uncorrected is predicted to be greater than the engine performance degradation that would occur when the control target is corrected.

Abstract: A method and control system to accomplish knock control on a multi-cylinder spark-ignition internal combustion engine equipped variable cam phasing system, comprising monitoring cam position, crankshaft position, and, engine knock signal, determining cam position relative to crankshaft position, and implementing either a global cylinder knock control strategy or an individual cylinder knock control strategy, based upon whether the determined cam position relative to crankshaft position is near a default position, the determined cam position indicates the variable cam phasing system is operating in a transient mode, or, the determined cam position relative to crankshaft position is substantially different from the default position.

Abstract: A method and a device for knock control of an internal combustion engine, in which an adjustment of the ignition angle takes place. When knocking occurs, the ignition angle is retarded and then advanced again. An increasing advance adjustment of the ignition angle reduces the rate of the advance adjustment.

Abstract: A method for computing an ignition angle of an internal combustion engine as a function of the operating conditions of the engine and knock signals K, which indicate knocking combustion in the engine. If knock occurs, the ignition angle is retarded. If knock stops for a first period, the ignition angle is advanced again. Advance of the ignition angle is limited on the basis of the first period. If knock stops for a second period, which exceeds the first period, the ignition angle is further advanced.

Abstract: Devices and methods for knock detection and knock control are described, in which, in addition to the customary component parts, the knock-detection circuit has a filter with switchable filter characteristic. The switchover of the filter characteristic, i.e. the shift, for example, of the mid-frequency of the filter, is carried out taking into consideration specifiable quantities or parameters, for instance, as a function of rotational speed. During the switchover of the filter characteristic, i.e. the shift of the mid-frequency, problems could occur in the knock detection; that is why measures are proposed which carry out the knock detection according to a special knock-detection algorithm during a switchover phase lasting a specifiable time.

Abstract: A knocking control apparatus for an internal combustion engine, which is applied to an internal combustion engine including a variable valve mechanism that can vary a valve characteristic of at least one of an intake valve and an exhaust valve, and which changes an engine control amount based on a result of a knocking determination as to whether knocking occurs, includes a controller which performs the knocking determination as to whether knocking occurs based on an output signal from a knock sensor that detects a vibration occurring in the internal combustion engine, and which changes a mode of the knocking determination according to a change in a combustion state of an air-fuel mixture, the change being caused by a change in the valve characteristic.

Abstract: An internal combustion engine (1) causes an air/fuel mixture in a cylinder to combust due to ignition by a spark plug (14). An engine controller (50) calculates an ignition delay of the gas in the cylinder on the basis of an operational state of the engine (1)(53), and it calculates a knock generation index which is an indicator of the occurrence of knock on the basis of the ignition delay (53). The controller (50) calculates a limit ignition timing at which knock is not generated, on the basis of the knock generation index (54), and by controlling the ignition timing of the spark plug (14) to the limit ignition timing (55), appropriate control of the ignition timing is achieved by means of a small number of adaptation steps.

Abstract: A combustion control system for a spark ignition internal combustion engine, is configured to detect engine operating conditions, predict, based on the detected engine operating conditions, an autoignition timing of an end gas and an amount of heat released due to autoignition of the end gas, calculate a knock intensity from the autoignition timing and the amount of heat released due to the autoignition, and control combustion in the engine in such a manner that the knock intensity is lower than or equal to a specified intensity limit.

Abstract: A method for reducing the magnitude of a knock retard angle in a vehicle having a quantity of fuel and a system for determining the quantity of fuel. The method determines a previous fuel quantity and a present fuel quantity, determines from said present fuel quantity and said previous fuel quantity whether the quantity of fuel has increased; and decreases the magnitude of the knock retard angle upon determining the quantity of fuel has increased.

Abstract: High octane fuel and low octane fuel are supplied into the combustion chamber of an engine from high-octane fuel tank and low octane fuel tank via a high octane fuel injector and a low octane fuel injector. During a knocking control, if the quantity of high and low octane fuels in the respective tanks has been unbalanced, the supply ratio between high octane fuel and low octane fuel is changed 1 to control a knocking occurring in the engine without changing the ignition timing.

Abstract: A knock control system for an internal combustion engine having a plurality of cylinders. Operation of the engine is switchable between a partial-cylinder operation for operating some of the cylinders and an all-cylinder operation for operating all of the cylinders. A determination threshold for determining knocking is set according to an output signal from the knock sensor. A level of the output signal from the knock sensor is compared with the determination threshold, and occurrence of knocking is determined according to a result of the comparison. The determination threshold used during the partial-cylinder operation is set to a value less than a value of the determination threshold used during the all-cylinder operation.

Abstract: In a compression ratio controlling apparatus and method for a spark-ignited internal combustion engine, the variable compression ratio mechanism is controlled by a compression controlling section on the basis of a detected engine speed and engine load in such a manner that the compression ratio is varied toward a target high compression ratio when the engine load falls in a predetermined low load region and toward a target low compression ratio when the engine load falls in a predetermined high load region and a predetermined delay is provided in a variation in the compression ratio toward one of the target high and low compression ratios in accordance with at least one of an engine driving history immediately before a transient state of a change in the engine load occurs and a wall temperature of a combustion chamber of the engine immediately before the transient state thereof occurs.

Abstract: Based on results of a knock control for adjusting ignition timing in accordance with the occurrence of knocking, an electronic control unit computes deposit required ignition timing akgrg, which is ignition timing determined by taking adhesion of deposits in an internal combustion engine into consideration. Based on the deposit required ignition timing akgrg, the electronic control unit reduces a vvt allowable variable range of a target VVT advancement amount, which is a control target value of a variable valve timing mechanism. The electronic control unit corrects a required ignition timing based on the actual VVT advancement amount vt, which is chanted according to the reduction of the allowable variable range of the target VVT advancement amount. As a result, problems resulting from the adhesion of deposits are effectively avoided.

Abstract: A misfire detector is provided that is accurate even in the case of a disturbance due to causes such as driving on a rough road. The misfire detector is equipped with a crankshaft revolution detector to measure the time period required for the crankshaft of an internal-combustion engine to revolve for a given angle. A signal-processor is also provided for detecting the misfiring of the internal-combustion engine by processing the time period. In one embodiment, the misfire detector has two filters having the same sensitivity to the misfire frequency, and differing in the sensitivity to frequencies adjacent to said misfire frequency. It can be determined that a misfire has occurred if the ratio or difference between the outputs of the two filters stays within a fixed range and one or both of the filters have respective outputs exceeding a threshold value.

Abstract: The invention provides such a knock control apparatus or method for an internal combustion engine as is capable of suitably avoiding an erroneous determination on the occurrence of knocking and controlling knocking. This control apparatus comprises a knock determiner, a controller, and a setter. If an intensity of engine oscillation detected during a predetermined knock determination period is equal to or higher than a predetermined knock determination level, the knock determiner determines that knocking has occurred. The controller controls an ignition timing on the basis of a result of the determination. The setter sets an end timing of the knock determination period at an advanced timing on the basis of the ignition timing retardation amount in the retardation control.

Abstract: A method of operating a knock detection system of a multi-cylinder piston engine in which the knock detection system comprises a sensor arranged in connection with each cylinder and a measurement circuit connected to the sensor includes running the engine at a load being less than full load and setting the output signal of each separate sensor between certain preset limits by adjusting one or more adjustment variables of the measurement circuit. The values of the adjustment variables for each separate cylinder are stored in the detection system. During normal use, the engine is run and the previously stored values of the adjustment values for each cylinder are used in the knock detection system.

Abstract: An engine is provided with a variable valve mechanism capable of changing a degree of an operating angle and a phase of a valve-open period of an intake valve. A controller selectively executes at least one of a plurality of knock controls including a phase adjustment of the valve-open period of the intake valve when a knocking is detected by a knock sensor. When the operating angle of the intake valve is smaller than 180 degrees, a knock control is selected and executed such that a valve-open timing IVO of the intake valve does not exceed a predetermined timing (TDC+?) retarded from a top dead center TDC by a predetermined angle ?. Specifically, for example, when the operating angle is smaller than 180 degrees and the valve-open timing IVO of the intake valve is after the top dead center TDC, the valve-open timing IVO is advanced.

Abstract: A method and apparatus that permit anti-knock control without the use of separate knock detectors as well as controlling the basic ignition timing from the output of a single engine speed sensor.

Abstract: This invention relates to a method in connection with engine control, wherein a combustion feedback signal is derived by measuring one or more combustion related parameters during a chosen time period of a first combustion cycle, for control of a possible fault, wherein at least one reference feature for said parameters has been determined previously, and comparing said measured combustion feed back signal with said reference feature for automatic adaptation of at least one combustion related variable during a forthcoming combustion cycle wherein at least one reference features for each one of at least two different fault situations having been determined previously, and that a diagnosis 3 of said first combustion cycle is performed on the basis of said combustion feedback signal being processed and compared (T1-Tn) with each one of said reference features, the result of which is analysed by a decision logic, whereafter a diagnosis (D) is established by means of which one or more variables in a forthcoming co

Abstract: A method for controlling spark timing. A plurality of tables provides borderline timing data contributors for each of a corresponding one of a plurality of different engine operating conditions. The contributors in each table are a function of engine speed and air charge. Background borderline spark timing is determined at a background computational rate from a summation of the borderline timing data in the plurality of tables data in the plurality of tables at engine speed measured at the borderline computational rate and air charge determined at the borderline computational rate. A one-dimensional table has borderline timing data contributors extracted from the provided tables. The extracted borderline timing data contributors are the engine sped measured at the borderline computational rate and the air charge determined at the borderline computational rate. From the one-dimensional table, foreground borderline spark timing is determined at a higher, foreground computational rate.

Abstract: A combustion control system for a spark ignition internal combustion engine, is configured to detect engine operating conditions, predict, based on the detected engine operating conditions, an autoignition timing of an end gas and an amount of heat released due to autoignition of the end gas, calculate a knock intensity from the autoignition timing and the amount of heat released due to the autoignition, and control combustion in the engine in such a manner that the knock intensity is lower than or equal to a specified intensity limit.

Abstract: A method for controlling incidences of combustion in an unloaded internal combustion engine of a vehicle. The method includes, determining a load-dynamics threshold, detecting an unloaded operating state of the internal combustion engine, detecting an incidence of the load-dynamics threshold being exceeded in the unloaded operating state, and retarding the ignition timing to form a load-dynamics aiming-off allowance that prevents combustion knock.

Abstract: A method for controlling spark timing. A plurality of tables provides borderline timing data contributors for each of a corresponding one of a plurality of different engine operating conditions. The contributors in each table are a function of engine speed and air charge. Background borderline spark timing is determined at a background computational rate from a summation of the borderline timing data in the plurality of tables data in the plurality of tables at engine speed measured at the borderline computational rate and air charge determined at the borderline computational rate. A one-dimensional table has borderline timing data contributors extracted from the provided tables. The extracted borderline timing data contributors are the engine speed measured at the borderline computational rate and the air charge determined at the borderline computational rate. From the one-dimensional table, foreground borderline spark timing is determined at a higher, foreground computational rate.

Abstract: An upper limit guard is set for a valve overlap amount according to a KCS learning value used to retard-correct an ignition timing in order to suppress knock, and an engine load. As a result, it is possible to make the upper limit guard value a value able to restrict the valve overlap amount to a value equal to, or less than, a value at which an internal EGR amount does not become exvessive during a retard-correction of the ignition timing. By applying the upper limit guard to the valve overlap amount using the upper limit guard value, it is possible to suppress the valve overlap amount from increasing from the optimum value following a retard-correction of the ignition timing, as well as suppress the value of overlap amount from being reduced when it is not deviating from the optimum value and is below the upper limit guard value.

Abstract: A method for knock control of an internal combustion engine, a knock detection being carried out on the cylinders of the internal combustion engine and a moment of ignition being retarded by a specifiable value as a function of detected knocking combustion in at least one of the cylinders, the system including at least two evaluation electronics and at least one cylinder being assigned to each of these evaluation electronics, and the knock sensor signals assigned to the cylinders being evaluated by the evaluation electronics assigned in each case, and the knock detection and the specification of the moment of ignition being effected by a control electronics, and the evaluation electronics being monitored for functionality. It is provided that, upon detection of a malfunction of at least one of the evaluation electronics, the at least one cylinder assigned to this evaluation electronics is linked to the control of at least one cylinder having intact evaluation electronics.

Abstract: A combustion control system for a spark-ignition internal combustion engine includes a variable piston stroke characteristic mechanism changing a compression ratio of the engine, sensors detecting engine operating conditions, i.e., engine speed and engine load, and at least one of a variable lift and working-angle control mechanism simultaneously continuously changing an intake-valve lift and an intake-valve working angle and a variable phase control mechanism changing an angular phase at a central angle corresponding to a maximum valve lift point of the intake valve. Also provided is a control unit that controls the variable piston stroke characteristic mechanism, and at least one of the variable lift and working-angle control mechanism and the variable phase control mechanism, depending on the engine operating conditions.

Abstract: An arrangement for regulating a spark-ignition internal combustion engine, in particular a stationary boosted gas Otto-cycle engine, comprising a power regulating device acting on at least one power setting member, wherein an ignition time regulating device (8, 9, 10) adjusts the ignition time (ZZP) in dependence on the position of the power setting member (2).

Abstract: A method for operating a motor vehicle having an internal combustion engine. In the method, the operation of the motor vehicle is influenced as a function of at least one operating parameter determined during an operating time of the motor vehicle. In order to take wear and tear of the motor vehicle and the internal combustion engine into consideration, an operating parameter suitable for determining wear and tear of the motor vehicle is detected, a value corresponding to the wear and tear is determined, and the operation of the motor vehicle is adjusted according to the determined value.

Abstract: An internal combustion engine is provided with a VVT mechanism capable of adjusting overlap period in which both intake and exhaust valves are open. The internal combustion engine is also provided with a recirculation mechanism that recirculates exhaust gas to the intake side. An EGR map from which internal EGR amount based on the VVT mechanism and external EGR amount based on the recirculation mechanism are derived in accordance with engine speed and engine torque is prepared. The EGR map is realized as a four-dimensional map that also takes engine intake air temperature and engine coolant temperature into account. By performing EGR control in consideration of these parameters, the occurrence of knocking during EGR control can be suppressed, and an improvement in fuel consumption and the like can be achieved with certainty.

Abstract: A method and a device for operating an internal combustion engine are provided, in which in at least one cylinder, combustion of a fuel in a fuel/air mixture introduced into the cylinder takes place. Upon the occurrence of knocking, a baseline ignition angle in the at least one cylinder is retarded in steps, using a knock control system, to an adjustment angle from the basic ignition angle. When the adjustment angle exceeds a definable threshold value, activation of the knock prevention operation mode occurs, in which context an additional action reducing the knock susceptibility of the fuel/air mixture is taken and the adjustment angle is decreased so that the baseline ignition angle is advanced.

Abstract: A knock control system is configured to precisely determine situations in which the knock signal cannot be detected and to suppress the occurrence of reductions in fuel efficiency, exhaust performance, and output performance. The knock control system has a knock sensor that detects an engine knocking condition to produce a knock signal of a prescribed level and a variable valve mechanism that can change the intake valve closing timing. Based on the ratio of the estimated knock signal during knocking to the estimated noise signal during no knocking, the knock control system determines if an accurate knock signal can be detected. The knock control system also determines if the valve seating position corresponding to the intake valve closing timing is within the knock detection interval and, if so, the estimated mechanical noise component of the estimated noise signal is updated.

Abstract: A method for operating an internal combustion engine and a corresponding device are described, in which reference pulses are generated synchronously with respect to the cyclical movement of at least one part of the internal combustion engine. At least one event moment for the occurrence of at least one event is calculated by an output unit at specific, definitively preset time intervals of the cyclical movement. Moreover, an independent clock-pulse generator is provided which generates clock pulses, the interval of the clock pulses being independent of the movement, and the interval of the clock pulses being smaller than the interval of the reference pulses. The at least one event moment is expressed as the number of clock pulses of the independent clock-pulse generator, and the at least one event is triggered upon reaching the number of clock pulses.

Abstract: The invention provides such a knock control apparatus or method for an internal combustion engine as is capable of suitably avoiding an erroneous determination on the occurrence of knocking and controlling knocking. This control apparatus comprises a knock determiner, a controller, and a setter. If an intensity of engine oscillation detected during a predetermined knock determination period is equal to or higher than a predetermined knock determination level, the knock determiner determines that knocking has occurred. The controller controls an ignition timing on the basis of a result of the determination. The setter sets an end timing of the knock determination period at an advanced timing on the basis of the ignition timing retardation amount in the retardation control.

Abstract: A method for regulating knocking in an internal combustion engine, particularly of a motor vehicle, has the following steps: determining a knocking combustion for a calculated first base ignition angle in one or more cylinders of the internal combustion engine originated from a previous operating condition; and setting a new, second base ignition angle taking into account the existing operating condition. A query concerning the relative sizes of a setpoint ignition angle for efficiency reduction and the first base ignition angle is provided for setting the second base ignition angle to allow for knocking regulation which is favorable to the operation. If the setpoint ignition angle is smaller than the base ignition angle, an ignition angle retardation is performed with an adjustment value that must be adjusted, and which is given by the sum of a previously determined, constant retardation value and an adjusted, variable retardation value.

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

Abstract: In a compression ratio controlling apparatus and method for a spark-ignited internal combustion engine, the variable compression ratio mechanism is controlled by a compression controlling section on the basis of a detected engine speed and engine load in such a manner that the compression ratio is varied toward a target high compression ratio when the engine load falls in a predetermined low load region and toward a target low compression ratio when the engine load falls in a predetermined high load region and a predetermined delay is provided in a variation in the compression ratio toward one of the target high and low compression ratios in accordance with at least one of an engine driving history immediately before a transient state of a change in the engine load occurs and a wall temperature of a combustion chamber of the engine immediately before the transient state thereof occurs.

Abstract: The method and the device are used for cylinder shut-off in an internal combustion engine (10), in particular of a vehicle, using a control unit (15) in effective operational contact with the cylinders (11, 12, 13, 14) of the internal combustion engine (10), which has a monitoring unit (21), a knock regulating unit (20) and a fuel injector shut-off unit (22). At the same time the provision is made that the fuel injector shut-off unit (22) is operationally linked to the knock regulating unit (20) to achieve coordinated cylinder shut-off. The fuel injector shut-off unit (22) is provided with a memory medium (23) for storing a cylinder shut-off program.

Abstract: An engine is provided with a variable valve mechanism capable of changing a degree of an operating angle and a phase of a valve-open period of an intake valve. A controller selectively executes at least one of a plurality of knock controls including a phase adjustment of the valve-open period of the intake valve when a knocking is detected by a knock sensor. When the operating angle of the intake valve is smaller than 180 degrees, a knock control is selected and executed such that a valve-open timing IVO of the intake valve does not exceed a predetermined timing (TDC+&agr;) retarded from a top dead center TDC by a predetermined angle &agr;. Specifically, for example, when the operating angle is smaller than 180 degrees and the valve-open timing UVO of the intake valve is after the top dead center TDC, the valve-open timing IVO is advanced.

Abstract: The invention relates to a method for adaptively controlling knocking and to a corresponding device for a gasoline direct fuel injection internal combustion engine, whereby the internal combustion engine is operated in at least two operational states. For controlling knocking, relevant late advance angles of the ignition angle are controlled by means of an adaptable adaptation process. A separate adaptation mapping or a separate adaptable computation rule is provided each time for both operational states, whereby, during a change of the operational state, the actual late advance angle is read out of the adaptation mapping of the new operational state or is calculated using the new adaptable calculation rule.

Abstract: A knock control system is configured to precisely determine situations in which the knock signal cannot be detected and to suppress the occurrence of reductions in fuel efficiency, exhaust performance, and output performance. The knock control system has a knock sensor that detects an engine knocking condition to produce a knock signal of a prescribed level and a variable valve mechanism that can change the intake valve closing timing. Based on the ratio of the estimated knock signal during knocking to the estimated noise signal during no knocking, the knock control system determines if an accurate knock signal can be detected. The knock control system also determines if the valve seating position corresponding to the intake valve closing timing is within the knock detection interval and, if so, the estimated mechanical noise component of the estimated noise signal is updated.

Abstract: An internal combustion engine is provided with a VVT mechanism capable of adjusting overlap period in which both intake and exhaust valves are open. The internal combustion engine is also provided with a recirculation mechanism that recirculates exhaust gas to the intake side. An EGR map from which internal EGR amount based on the VVT mechanism and external EGR amount based on the recirculation mechanism are derived in accordance with engine speed and engine torque is prepared. The EGR map is realized as a four-dimensional map that also takes engine intake air temperature and engine coolant temperature into account. By performing EGR control in consideration of these parameters, the occurrence of knocking during EGR control can be suppressed, and an improvement in fuel consumption and the like can be achieved with certainty.

Abstract: The method is used for controlling incidences of combustion in an unloaded internal combustion engine (10) of a vehicle.

Abstract: A method and apparatus that permit anti-knock control without the use of separate knock detectors as well as controlling the basic ignition timing from the output of a single engine speed sensor.

Abstract: A fuel injection method for an internal combustion engine, an injection being implemented either in homogeneous normal operation or in inhomogeneous stratified operation. In doing so, a characteristic value for knock is detected in at least one cylinder of the internal combustion engine in inhomogeneous stratified operation. At least the one cylinder is switched over from inhomogeneous stratified operation to homogeneous normal operation if the detected characteristic value of the one cylinder meets a predetermined first criterion.

Abstract: A diagnostic method for a motor vehicle having an internal combustion engine operable in a plurality of compression ratio operating states includes the steps of determining a change in spark adjustment required to avoid knock as the engine is operated in selected ones of the compression ratio operating states, and evaluating operation of the internal combustion engine based at least in part on the change in spark adjustment.

Abstract: A control system for an internal combustion engine is provided which comprises a compression ratio control mechanism and a control unit for controlling the compression ratio control mechanism. The control unit including an acceleration parameter obtaining section for obtaining an acceleration parameter corresponding to a change of an engine speed, an acceleration determining section for determining whether the engine is in a slow or fast acceleration state on the basis of the acceleration parameter, and a control section for controlling at least one of a compression ratio change speed at which the engine compression ratio during engine acceleration is changed and a compression ratio change start time at which a change of the engine compression ratio during engine acceleration is started, on the basis of whether the engine is in a slow or fast acceleration state. A control method is also provided.

Abstract: A device for signal evaluation is described, in particular for knock recognition in an internal combustion engine, in which the signals forwarded by sensors are evaluated digitally and error recognition is carried out that performs two different test functions, whereby a first test function supplies a test pulse at a specifiable location, and the second test function clears the sensor signals, and the reaction of both the analog and digital parts of the circuit are monitored.

Abstract: The method and the device are used for cylinder shut-off in an internal combustion engine (10), in particular of a vehicle, using a control unit (15) in effective operational contact with the cylinders (11, 12, 13, 14) of the internal combustion engine (10), which has a monitoring unit (21), a knock regulating unit (20) and a fuel injector shut-off unit (22). At the same time the provision is made that the fuel injector shut-off unit (22) is operationally linked to the knock regulating unit (20) to achieve coordinated cylinder shut-off. The fuel injector shut-off unit (22) is provided with a memory medium (23) for storing a cylinder shut-off program.

Abstract: To provide a knock control system for an internal combustion engine, with which appropriate ignition timing control for each cylinder can be made. The knock control system includes knock detectors outputting a knock detection signal; a unit setting a threshold value for a knock judgement performed on the knock detection signal; a unit performing a knock judgement based on the threshold value and the knock detection signal; a unit setting a control parameter correction request amount at least including ignition timing, based on the knock judgement result; a unit correcting the control parameter by setting a control parameter correction amount based on a control parameter correction request amount; and a variation correction unit performing a correction to reduce variation in a cylinder when at the knock detection result and the control parameter correction amount from at least one cylinder varies greatly with respect to other cylinders.