Abstract:
When an engine is at starting or at cold state, a closing time of an exhaust valve is set before an intake top dead center to close the exhaust valve early. An exhaust residual gas is compressed by a cylinder to raise an inner cylinder temperature. A pre-fuel injection is performed from a time of closing the exhaust valve to a time of the intake top dead center in such a manner that the pre-injected fuel is combusted to raise the inner cylinder temperature. This increase in temperature expedites an atomization of fuel injected at a main fuel injection. A wet amount of fuel is reduced and HC emission is also reduced.
Abstract:
A motor current (driving current of motor) is estimated based on a target motor speed, an actual motor speed, and an engine speed. When the estimated motor current exceeds the upper limit value equivalent to a heat generation limiting current, the motor current is restricted by restricting a variation (motor speed F/B amount) in target motor speed outputted to an EDU from an ECU. If it is continued that a deviation between the target motor speed and the actual motor speed exceeds a predetermined value, the estimated motor current exceeds this upper limit value and the restricting action of the motor current is continued.
Abstract:
A waveform knock signal detected by a knock sensor is filtered through a band-pass filter. The detected wave form signal is compared with an ideal reference knock waveform to determine an engine knock. The ideal reference knock waveform is derived on the basis of a factor depending on a crank angle, a factor depending on a real time and a factor depending on an engine construction. The factor depending on the real time is calculated based on an energy loss in a combustion chamber and a time constant of the band-pass filter. The factor depending on the engine construction is calculated based on a knock vibration which is generated in a cylinder, transferred to a cylinder block and detected by the knock sensor.
Abstract:
A variable valve timing adjuster with an intermediate lock mechanism learns a lock position and a lock release control. During a lock control, a learning of the lock position from a real camshaft phase is repeated to update the learned value, and the learning is ended when it is judged that the learned values have converged. At this time, when the learned values of the lock position do not converge even if the number of learning of the lock position exceeds a predetermined value, an insufficient lock state is judged, and the learned value of the lock position is set to an initial value or the learned value at the previous lock control thereby to make a lock release control. During the lock release control, on the other hand, the control (or the lock release control) of a hydraulic control valve is learned. When the lock cannot be released during the lock release control, the lock release control (or the learned value) is corrected in a direction to facilitate the lock release. When the correction of the lock release control is repeated a predetermined or more number of times or when the lock release control goes outside a predetermined range, the lock release failure is judged.
Abstract:
A control device projects a lock pin to lock a VCT phase in an intermediate lock phase when a lock request occurs. A learning unit learns one of a most retarded phase, a most advanced phase, and an intermediate lock phase, as a reference phase. A control unit sets a target phase according to the reference phase and controls the control device. A monitor unit determines that the VCT phase has passed through the intermediate lock phase when the lock request occurs before completion of learning of the reference phase, and when a change in the VCT phase becomes greater than a threshold. The threshold is set to be greater than a sum of i) a design value of a phase difference between the intermediate lock phase and one of the most retarded phase and the most advanced phase and ii) a range of a product variation of the phase difference.
Abstract:
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.
Abstract:
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.
Abstract:
When an engine is at starting or at cold state, a closing time of an exhaust valve is set before an intake top dead center to close the exhaust valve early. An exhaust residual gas is compressed by a cylinder to raise an inner cylinder temperature. A pre-fuel injection is performed from a time of closing the exhaust valve to a time of the intake top dead center in such a manner that the pre-injected fuel is combusted to raise the inner cylinder temperature. This increase in temperature expedites an atomization of fuel injected at a main fuel injection. A wet amount of fuel is reduced and HC emission is also reduced.
Abstract:
An ECU outputs a signal indicative of a target motor speed calculated based on a deviation between a target camshaft phase and an actual camshaft phase to an EDU. The EDU performs a feedback control of the output current (motor current) of the EDU so that the deviation is decreased, whereby an actual camshaft phase is feedbacked to a target camshaft phase. When the supply voltage of EDU is less than the operation limit voltage established higher than minimum operation assurance voltage, the variation of the target motor speed is restricted. Thereby, the output current of EDU is restricted, and further, when the supply voltage is less than minimum operation assurance voltage, the output current of EDU is intercepted.