Denso Corporation

Toyota Jidosha Kabushiki Kaisha

Nippon Soken, Inc.

Yuichi Takemura

Rihito Kaneko

Kenji Kasashima

Kenji Senda

Masatomo Yoshihara

Shuhei Oe

Koji Aso

Shigeru Kamio

Kiyoshi Iwade

Masaomi Inoue

Satoshi Masuda

Shingo Nakata

Nobuyuki Murate

Norihito Hanai

Yasuhiro Yamasako

Minoru Wada

Kouzi Ohara

Kouji Ohara

Shuhei c/o Nippon Soken Inc Oe

Nobuyuki c/o Nippon Soken Inc Murate

Kiyoshi c/o Nippon Soken Inc Iwade

Nobuyuki c/o Nippon Soken Inc 14 Murate

Rihito c/o Toyota Jidosha Kabushiki Kaneko

Kiyoshi c/o Nippon Soken Inc 14 Iwade

Shuhei c/o Nippon Soken Inc 14 Iwaya Oe

A variable valve timing control apparatus adjusts the rotation phase (VCT phase) of an engine camshaft by selectively supplying oil to an advancement chamber and a retardation chamber, and includes a lock pin which is controlled for being moveable to a first position, in which the rotation phase is adjustable, and a second position, in which the camshaft is locked at a specific rotation phase. When the lock pin is displaced from the first position, oil becomes enabled to pass between the advancement chamber and retardation chamber, to thereby enabling the rotation phase to be changed to the specific rotation phase by supplying oil to an appropriate one of the advancement chamber and a retardation chamber, for initiating locking.

Variable valve timing control apparatus for internal combustion engine

A variable valve timing control apparatus for an engine includes a hydraulic variable valve timing unit and an oil pressure control device. The variable valve timing unit has a plurality of control ranges and an ambiguity range. The apparatus learns a hold control amount for each of the plurality of control ranges when a predetermined condition is satisfied, and the hold control amount is required to control the oil pressure control device to maintain the actual VCT phase. When the target VCT phase is positioned in the ambiguity range, if a difference between the actual and target VCT phases is stably greater than a predetermined value, the apparatus switches the presently-used hold control amount learning value of one control range into the learning value for the other control range in order to compute the VCT control amount.

An engine ECU executes operations including: extracting vibration intensities of a plurality of frequency bands from vibration detected by a knock sensor, multiplying the extracted vibration intensity of each frequency band by a weight coefficient and adding the results in correspondence with crank angles to calculate integrated values of every five degrees; calculating a coefficient of correlation based on a result of comparison between a vibration waveform of a frequency band and a knock waveform model prepared in advance; calculating a knock intensity; determining occurrence of knocking in accordance with the calculated coefficient of correlation and the knock intensity; and determining no occurrence of knocking in accordance with the calculated coefficient of correlation and the knock intensity.

Knock determination device and knock determination method for internal combustion engine

A variable valve timing control apparatus for an internal combustion engine having a crankshaft and a camshaft, the variable valve timing control apparatus including a hydraulic variable valve timing device, an intermediate lock mechanism, and an oil pressure control device. The control apparatus learns an intermediate lock position to obtain a learning value of the intermediate lock position when the intermediate lock mechanism locks the VCT phase at the intermediate lock position. The control apparatus computes an actual VCT phase based on the learning value of the intermediate lock position. The control apparatus computes a target VCT phase in accordance with an operational condition of the engine based on the learning value of the intermediate lock position. The control apparatus controls a control amount of the oil pressure control device such that the actual VCT phase becomes the target VCT phase.

A variable valve timing control apparatus is provided for an internal combustion engine that has a crankshaft, a camshaft, a hydraulic variable valve timing unit, a lock pin, and a hydraulic control valve. The hydraulic control valve is configured to control oil pressure that actuates the variable valve timing unit and the lock pin. The control apparatus switches a control, based on an operational state, between (a) a variable cam timing (VCT) phase control for controlling the VCT phase to a target phase and (b) a lock pin projection control for allowing the lock pin to project. The control apparatus executes, when an abnormality occurs, a foreign object release control for changing a control amount of the hydraulic control valve based on a predetermined pattern, wherein the control apparatus changes the predetermined pattern depending on the abnormality in the execution of the foreign object release control.

In a variable valve timing control apparatus, a hydraulic variable valve timing device adjusts valve timing by changing a VCT phase. In a lock mode, the lock pin is allowed to be displaced in a lock direction for locking the VCT phase, and the VCT phase is slightly shifted in a lock-mode VCT phase shift direction corresponding to one of an advance direction and a retard direction. A lock control unit shifts the VCT phase in a direction opposite from the VCT phase shift direction if the VCT phase is located on a lock-mode VCT phase shift direction side of the intermediate lock position when the engine becomes equal to or less than a first rotational speed, and otherwise the lock control unit allows the lock pin to be displaced in the lock direction.

An engine ECU executes a program including: detecting a magnitude of vibration of an engine; detecting a vibration waveform of the engine based on the magnitude; calculating a correlation coefficient, in the case where the engine speed is smaller than a threshold value, using the sum of values each determined by subtracting a positive reference value from a magnitude of a knock waveform model, as an area of the knock waveform model and, calculating the correlation coefficient, in the case where the engine speed is not smaller than the threshold value, using the area of the whole knock waveform model; and determining whether or not knocking has occurred using the correlation coefficient. The correlation coefficient is calculated by dividing by the area the sum of differences that are each the difference between the magnitude on the vibration waveform and the magnitude on the knock waveform model.

Knocking determination device and knocking determination method for internal combustion engine

A variable valve timing control apparatus for an engine includes a variable valve timing unit, a lock pin, a hydraulic control unit, and a lock control unit. The lock control unit causes the lock pin to lock the camshaft phase at an intermediate lock phase when a lock request is issued. When the lock request is issued, the camshaft phase is shifted in a reference direction to go beyond the intermediate lock phase while the lock pin is urged in a lock direction. When the camshaft phase stops around the intermediate lock phase, the lock control unit changes a control amount of the hydraulic control unit by a certain amount to shift the camshaft phase. The lock control unit determines that the camshaft phase has been locked at the intermediate lock phase when the camshaft phase is not shifted even after the lock control unit changes the control amount.

An engine ECU executes a program that includes: calculating a median value and a standard deviation based on a calculated value based on the detected vibration of the engine; and subtracting a product of the standard deviation and a coefficient from the median value to calculate a magnitude of mechanical vibration specific to the engine. Knocking determination is carried out by comparing a knock magnitude calculated by dividing the magnitude value of the peak magnitude of the detected vibration of the engine by the magnitude of mechanical vibration specific to the engine with a predetermined determination value. Based on the knocking determination result, ignition timing of the engine is controlled.

Device and method for controlling ignition timing of internal combustion engine

A device and associated method for controlling ignition timing of an internal combustion engine are provided. By comparing a determination value and knock magnitude, determination of knocking is made, and ignition timing is advanced or retarded. The device includes an operation unit that sets a correction amount of the determination value to a value corresponding to a degree of change of the determination value over time. The operation unit calculates, at a first timing, a first value related to an average value of the determination values; and calculates, at a second timing later than the first timing, a second value related to the average value of the determination values. The degree of change of the determination value is calculated as a difference between the first value and the second value.

An engine ECU executes a program including the steps of: detecting a vibration corresponding to a first radial resonance mode by using a band-pass filter, from vibrations sensed by an in-cylinder pressure sensor provided at an upper central portion of the cylinder; calculating knock intensity N based on a result of comparison between the detected waveform and a knock waveform model prepared in advance as a vibration waveform when knocking occurs; determining that knocking occurred when the knock intensity N is larger than a predetermined reference value; and determining that knocking has not occurred when the knock intensity N is not larger than the predetermined reference value.

Internal combustion engine knock determination device

An engine ECU executes a program including the steps of: calculating an absolute value &#x394;S(I) of the deviation of the vibration waveform detected by a knock sensor and a knock waveform model from each other at each crank angle; when &#x394;S(I) greater than threshold value &#x394;S() is present and the number of &#x394;S(I) greater than threshold value &#x394;S() is equal to or smaller than Q(), correcting the vibration waveform; calculating a correlation coefficient K which is a value related to the deviation of the corrected vibration waveform and the knock waveform model from each other; and when the number of &#x394;S(I) greater than threshold value &#x394;S() is greater than predetermined number Q(), calculating the correlation coefficient K without correcting the vibration waveform. Based on the correlation coefficient K, whether knocking is present or absent is determined.

Device and method for determining knocking of internal combustion engine

An engine ECU executes a program including: the step of increasing a determination value by a correction amount if the number of knock intensities not lower than the determination value is not smaller than a threshold value among knock intensities of a plurality of predetermined number of continuous ignition cycles; and the step of increasing the determination value by a correction amount if the number of knock intensities not smaller than the determination value is not smaller than a threshold value, among knock intensities of a plurality of ignition cycles satisfying the condition that a coefficient of correlation calculated by comparing a vibration waveform and a knock waveform model is not smaller than a threshold value, of the knock intensities of a plurality of predetermined continuous ignition cycles.

Internal combustion engine knock determination device and knock determination method

An engine ECU executes a program including the steps of: setting a knock waveform model corresponding to engine speed sensed by a crank position sensor; calculating knock intensity N based on the result of comparison between a detected waveform and the set knock waveform model; when the knock intensity N is larger than a predetermined reference value, determining that knocking has occurred; and when the knock intensity N is not larger than the predetermined reference value, determining that knocking has not occurred.

An engine ECU includes a bandpass filter () extracting only vibrations at a first frequency band A, a bandpass filter () extracting only vibrations at a second frequency band B, a bandpass filter () extracting only vibrations at a third frequency band C, and a bandpass filter () extracting only vibrations at a fourth frequency band D including the first to third frequency bands A-C. The engine ECU determines whether knocking occurred or not based on a vibration waveform of the fourth frequency band D and a peak value in magnitude of vibrations in a synthesized waveform of the first to third frequency bands.

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Anjo, Japan

Yuichi Takemura