An internal combustion engine knock determining device includes a vibration detector that produces a signal corresponding to engine vibration, an intensity computing unit that retrieves vibrational components in a plurality of frequency regions in which vibration intensity peaks are located when knock occurs, a background-noise computing unit that calculates background noise caused by factors other than knock, a frequency computing unit that determines specific frequency regions from which to determine whether knock is occurring by excluding certain frequency regions designated as frequency regions requiring exclusion due to the intensity of false-detection causing noise as a proportion of the background noise in the certain regions, and a knock determining unit that determines the occurrence of knock based on the vibration intensity in the specific frequency regions obtained by excluding the frequency regions requiring exclusion, wherein the number of specific frequency regions is increased to improve the accuracy of knock detection.

To provide a controller and a control method for internal combustion engine which can suppress the increase in the calculation processing load for determining occurrence of the mechanical noise and occurrence of the knocking with good accuracy even when the mechanical noise occurs. When the maximum value of the strength of the component of the second frequency band in the comparison period exceeds the maximum value of the strength of the component of the first frequency band, a controller for internal combustion engine performs a second side stop determination processing that determine whether the knocking occurred, based on the strength of the component of the first frequency band, without using the strength of the component of the second frequency band.

A normal control unit performs a normal control to cause an injection apparatus to perform predetermined normal injection and subsequently cause an ignition plug to perform ignition. In a delay region in a combustion chamber, propagation of flame is retarded further than in another region when the normal control is performed. In a knock state, self-ignition occurs in the delay region when the normal control is performed. When the knock state is established, an adjustment control unit performs, to suppress the self-ignition, an adjustment control to perform main injection and subsequently perform sub-injection in a second half of a compression stroke to adjust a fuel distribution in the combustion chamber to facilitate propagation of flame to the delay region further than in the normal control and subsequently cause the ignition plug to perform the ignition.

Methods and systems are provided for improving engine knock control by accounting for a drop in charge cooling efficiency of a knock control fluid at higher temperatures. In response to the prediction of an elevated temperature of a knock control fluid at a time of release from a direct injector, a pulse width of the injection is adjusted. Any knock relief deficits are compensated for using alternate engine adjustments, such as boost or spark timing adjustments.

A system for and a method of knock detection and control for an engine utilizes a knock sensor configured to generate a knock signal indicative of a vibration of the engine caused by abnormal combustion. A controller is configured to receive the knock signal, determine, with respect to a crank angle of the engine, distinct monitoring windows for low speed pre-ignition (LSPI) knock and spark knock, respectively, based on (i) spark timing and (ii) an appropriate mass fraction burn (MFB) location, monitor the knock signal using the distinct monitoring windows, detect one of LSPI knock and spark knock based on the monitoring, and control the engine to mitigate the detected LSPI knock or spark knock.

A system and method for detecting and mitigating automatic ignition in a cylinder of an internal combustion engine. The method includes providing a first sensor for sensing and determining a crank angle of a crankshaft of the engine. A second sensor is provided for detecting a change in an engine vibration frequency caused by Auto Ignition (AI). The engine vibration signal of the second sensor is processed into a knock intensity signal. The knock intensity signal is indicative of the cylinder pressure and is acquired when the crank angle is between a first predetermined crank angle and a second predetermined crank angle. At least one characteristic of the knock intensity signal is determined and the at least one characteristic of the knock intensity signal is compared to at least one predetermined characteristic threshold. If the at least one characteristic of the knock intensity signal is determined to exceed the at least one predetermined characteristic threshold, then at least one auto ignition mitigating action is performed to mitigate the auto ignition event.

Methods and systems are provided for controlling a vehicle engine to reduce engine knock and increase fuel efficiency by reducing hydrocarbon breakthrough. In one example, a method may include adjusting a compression ratio of a variable compression engine in response to hydrocarbon breakthrough above a threshold from a fuel vapor canister of an evaporative emissions system.

Provided is a signal processing device capable of effectively reducing a work load of a parameter setting operator in response to an increase in parameters constituting complicated filter control. Therefore, in the signal processing device filters an output signal from a sensor mounted on a vehicle, setting is made with respect to a plurality of filters having different filter types or filter coefficients for setting a filter characteristic of a cutoff frequency or a pass band, an individual code is set for each of the plurality of filters, and the signal processing device includes a CPU that selects the individual code based on an engine operating state so that a corresponding filter is selected, and processes an output signal from the sensor using the filter that has been selected.

The purpose of the present invention is to provide an engine control device with which it is possible to minimize decreases in combustion speed even when the EGR rate has been increased. The present invention is an engine control device for: controlling an engine provided with an injector for injecting fuel directly into a cylinder, an ignition device for igniting the injected fuel, and an EGR means capable of recycling combustion gas and varying the EGR rate of the recycling combustion gas; and commanding the injector to perform multiple injections during one cycle, wherein a command is given to perform a control for increasing the injection quantity per compression stroke relative to the total injection quantity in one cycle so that the injection quantity per compression stroke is greater when the EGR rate is high than when the EGR rate is low, and/or a control for increasing the number of injections per compression stroke relative to the total number of injections in one cycle so that the number of injections per compression stroke is greater when the EGR rate is high than when the EGR rate is low.

An object of the present invention is to provide a technology that enables an abnormal combustion detection apparatus for a spark ignition internal combustion engine having a plurality of cylinders to detect abnormal combustion such as pre-ignition and knocking with improved accuracy. To achieve the object, according to the present invention, in an abnormal combustion detection apparatus for a spark-ignition internal combustion engine that determines or detects the occurrence of abnormal combustion by comparing a vibration intensity obtained from a measurement signal of a knock sensor and a determination threshold, when the occurrence of abnormal combustion is detected, the apparatus corrects a determination threshold for the next cylinder using as parameters the peak value of the vibration intensity at the time of the occurrence of abnormal combustion and the engine speed.