Abstract: In detecting the occurrence of an abnormality in a variable valve timing mechanism, which continuously changes a valve timing by advancing or delaying the displacement angle of an intake-side cam shaft with respect to a crankshaft, an abnormality detecting apparatus for a valve timing control apparatus determines that the variable valve timing mechanism is failing when the absolute value of the difference between a target displacement angle and a correct real displacement angle, obtained by subtracting the maximum delay-angle learning value from the real displacement angle, is greater than a first predetermined value and the absolute value of the difference between a correct real displacement angle and a previous correct real displacement angle is equal to or smaller than a second predetermined value.

Abstract: A valve timing control apparatus that adjusts valve overlap by altering valve timing according to the running condition of the engine. A variable valve timing mechanism (VVT) alters the valve timing of intake valves to adjust the valve overlap. An electronic control unit (ECU) controls the VVT with respect to a target value calculated in accordance to the running condition of the engine to obtain the optimum valve overlap. The ECU controls the VVT to eliminate valve overlap under low temperature conditions. The ECU controls the VVT to switch from a state of nonexistent valve overlap to a valve overlap state as the temperature changes from a low temperature to a higher temperature. The ECU judges whether the engine is in a low temperature condition based on a predetermined reference value to suppress the difference in the amount of fuel (port wet amount) adhered to the intake port before and after the shifting of the state the valve overlap.

Abstract: A valve timing control apparatus that continuously controls the valve timing of an intake valve or an exhaust valve of an engine. This apparatus includes a hydraulic variable valve timing mechanism, a hydraulic control valve and an electronic control unit for controlling the control valve. The variable valve timing mechanism alters the valve timing to change the valve overlap of the intake valve with respect to the exhaust valve. The hydraulic control valve controls the hydraulic pressure supplied to the variable valve timing mechanism. The real phase of the valve timing is coincided with a target phase that corresponds with the running conditions of the engine. When the real phase of the valve timing approaches the target phase, the hydraulic control valve is controlled to sustain the phase of that instant. The electronic control unit, which learns the control state of the valve-timing sustaining control, sets an initial learning value that reduces the valve overlap when the learning has started.

Abstract: Disclosed is a device for calculating an amount of an air introduced to a cylinder of an engine. An air-intake passage introduces the air to the cylinder. An air-exhaust passage exhausts gas from the cylinder. Both passages respectively have an intake valve and an exhaust valve. Both valves are respectively driven by an intake valve drive mechanism and an exhaust valve drive mechanism in accordance with a rotation of a crank shaft to alternatively and selectively open and close, and simultaneously open during a valve overlap period to open the passages to the cylinder. A variable valve timing mechanism controls an operational timing of the valve drive mechanisms with respect to the crank shaft in accordance with a running condition of the engine to vary a timing of the valve driven by the valve drive mechanisms. The calculating device comprises a first detecting device, which detects a rotational speed of the crank shaft. A second detecting device detects an intake pressure in the air-intake passage.

Abstract: A cam shaft of an engine is provided with a timing change mechanism (VVT) which is driven by hydraulic pressure to alter the timing of a intake valve (valve timing). This VVT is controlled to change the valve overlap of the intake valve and an exhaust valve, thereby adjusting the suction and exhaust in and from a combustion chamber. To control the VVT, an electronic control unit (ECU) computes a target value for the valve timing in accordance with the running condition of the engine and controls the supply of the hydraulic pressure to the VVT based on the target value. The ECU determines the level of the actual hydraulic pressure given to the VVT. When the actual valve timing does not lie in a predetermined range with respect to the target value, the ECU determines that an abnormality has occurred in the VVT, and executes a predetermined fail safe routine. When the hydraulic pressure is equal to or smaller than a reference value, the ECU suppresses VVT malfunction determinations.

Abstract: A cam shaft of an engine is provided with a timing change mechanism (VVT) which is driven by hydraulic pressure to alter the timing of a intake valve (valve timing). This VVT is controlled to change the valve overlap of the intake valve and an exhaust valve, thereby adjusting the suction and exhaust in and from a combustion chamber. To control the VVT, an electronic control unit (ECU) computes a target value for the valve timing in accordance with the running condition of the engine and controls the supply of the hydraulic pressure to the VVT based on the target value. The ECU determines the level of the actual hydraulic pressure given to the VVT. When the actual valve timing does not lie in a predetermined range with respect to the target value, the ECU determines that an abnormality has occurred in the VVT, and executes a predetermined fail safe routine. When the hydraulic pressure is equal to or smaller than a reference value, the ECU suppresses WT malfunction determinations.

Abstract: A varying mechanism (VVT) for continuously varying the valve timing of an intake valve in a predetermined range is provided on a cam shaft in an engine. By controlling the VVT, the valve overlap period of the intake valve and an exhaust valve is continuously varied in a predetermined range, thus adjusting the amount of the internal EGR in combustion chambers. When determining that the operational load of the engine is small and intermediate based on the value of a manifold pressure, an electronic control unit (ECU) computes a target value for advancing the valve timing with respect to the rotational phase of a crankshaft based on a throttle angle, an engine speed, etc. The ECU also computes a limit value to restrict the target value in accordance with the value of the manifold pressure. When the target value is smaller than the limit value, the ECU controls the VVT based on the target value.

Abstract: An apparatus to calculate the intake pipe pressure using the degree of throttle opening and the engine speed, to use this intake pipe pressure to calculate a current intake pipe pressure, and to determine a predicted value from this current intake pipe pressure and control fuel injection duration and/or spark timing. Becuase changes in the atmospheric pressure and changes in the air amount flowing through a bypass bypassing the throttle, etc., cause errors in the values predicted for the intake pipe pressure, there are irregularities in the exhaust emission. the atmospheric pressure and the intake pipe pressure, etc., detected by a pressure sensor are used to correct the predicted value, and prevent irregularities and the like in exhaust emissions.

Abstract: An apparatus to calculate the intake pipe pressure using the degree of throttle opening and the engine speed, to use this intake pipe pressure to calculate a current intake pipe pressure, and to determine a predicted value from this current intake pipe pressure and control fuel injection duration and/or spark timing. Because changes in the atmospheric pressure and changes in the air amount flowing through a bypass bypassing the throttle, etc., cause errors in the values predicted for the intake pipe pressure, there are irregularities in the exhaust emissions. The atmospheric pressure and the intake pipe pressure, etc., detected by a pressure sensor are used to correct the predicted value, and prevent irregularities and the like in exhaust emissions.

Abstract: A method for controlling fuel injection rate in internal combustion engine in accordance with the intake pressure and the engine speed. The method has the steps of determining the intake pressure using, as a variable, the period of time after a change in the throttle opening, and computing a basic fuel injection period on the basis of the thus computed intake pressure and the engine speed. The fuel injection is conducted by a system in accordance with this method. The system determines the intake pressure in the steady state of engine operation in accordance with the throttle opening and the fuel injection rate, effects a correction on the thus determined intake pressure so as to take into account a delay in response of the intake pressure to the transient period, and determines the basic fuel injection period on the basis of the corrected intake pressure and the engine speed.

Abstract: A fuel injection control device for an internal combustion engine comprising a throttle position sensor, a pressure sensor or a potentiometer for detecting a flow of the intake air in units of a certain physical quantity, and a third detecting device for detecting whether the engine is operating in a steady state. The device further includes a device for estimating the load of the engine from the output of the throttle position sensor and a learning device for correcting the estimation provided by the estimating device based on the output of the air flow sensor when the engine is operating in a steady state, so that the load estimation value can be corrected in accordance with the actual air flow. The amount of fuel to be injected is calculated in response to the most recently corrected load estimation value obtained from the output of the throttle position sensor.