Abstract: The ECU executes a program that includes the steps of: calculating the temperature Texp of the wall surface of the exhaust port and the temperature Tsen of the wall surface of the inner cover covering the zirconia element of the A/F sensor (S110); heating the zirconia element by the heater (S130) when at least one of the condition that the temperature Texp is equal to or higher than the first threshold and the condition that the temperature Tsen is equal to or higher than the second threshold is in effect (S120: YES); and prohibiting the heating of the zirconia element by the heater (S140) when the temperature Texp is lower than the first threshold and the temperature Tsen is lower than the second threshold (S120: NO).

Abstract: An engine ECU executes a program including the steps of: detecting an engine speed NE, engine load, and engine coolant temperature (S100, S110, S115); when determination is made of being in an idle region (YES at S120), determining whether in a cold idle region, a transitional region, or a warm idle region (S130); injecting fuel from an intake manifold injector alone when in the cold idle region (S140); injecting fuel from the intake manifold injector and injecting fuel from an in-cylinder injector at the feed pressure when in the transitional region (S150); and injecting fuel from the in-cylinder injector at the feed pressure when in the warm idle region (S160).

Abstract: The ECU executes a program that includes the steps of: calculating the temperature Texp of the wall surface of the exhaust port and the temperature Tsen of the wall surface of the inner cover covering the zirconia element of the A/F sensor (S110); heating the zirconia element by the heater (S130) when at least one of the condition that the temperature Texp is equal to or higher than the first threshold and the condition that the temperature Tsen is equal to or higher than the second threshold is in effect (S120: YES); and prohibiting the heating of the zirconia element by the heater (S140) when the temperature Texp is lower than the first threshold and the temperature Tsen is lower than the second threshold (S120: NO).

Abstract: In a V-type 8-cylinder engine in which the torque for rotating an intake camshaft is higher when intake valves of a #1 cylinder and a #3 cylinder in a left bank are closed, respective noses of a cam for opening and closing the intake valve of the #1 cylinder and a cam for opening and closing the intake valve of the #3 cylinder are each formed at a phase position displaced by X° (X>0) in the advance direction further from the phase position displaced in the advance direction by 90° with respect to the nose of a cam for opening and closing the intake valve of a cylinder fired after a delay of 180° in crank angle.

Abstract: An engine ECU executes a program including the steps of: detecting an engine speed NE, a throttle angle THA and an amount of intake air GA; estimating an amount of intake air GAINI from the engine speed NE and the throttle angle THA; if the estimated amount of intake air GAINI minus the detected amount of intake air GA is larger than a predetermined deviation ?GA(0) (YES at S104), then causing an intake manifold injector to inject fuel to clear a deposit, as controlled, at the exhaust stroke when an intake valve is closed and at the intake stroke when the intake valve is opened and an exhaust valve is closed.

Abstract: A fuel supplying apparatus of an internal combustion engine includes a first fuel supply system, a second fuel supply system, and a pulsation propagation suppressing unit. The first fuel supply system pressurizes a fuel by a low-pressure pump, and supplies the fuel pressurized by the low-pressure pump to a first fuel injection mechanism. The second fuel supply system is branched from the first fuel supply system, further pressurizes the fuel, pressurized by the low-pressure pump, by a high-pressure pump that is driven according to an operating state of the internal combustion engine, and supplies the fuel pressurized by the high-pressure pump to a second fuel injection mechanism. The pulsation propagation suppressing unit is provided in at least one of the first fuel supply system and the second fuel supply system, and suppresses propagation of a pulsation generated in the high-pressure pump to the first fuel injection mechanism.

Abstract: An ECU executes a program including the steps of: calculating a base timing of injection (INJB); determining whether an engine knocks; if the engine knocks, increasing a correction value INJK(I) applied to correct a timing of injection; and calculating the base timing of injection INJB plus the correction value INJK(I) to obtain a timing of injection INJ.

Abstract: A fuel supplying apparatus of an internal combustion engine includes a first fuel supply system, a second fuel supply system, and a pulsation propagation suppressing unit. The first fuel supply system pressurizes a fuel by a low-pressure pump, and supplies the fuel pressurized by the low-pressure pump to a first fuel injection mechanism. The second fuel supply system is branched from the first fuel supply system, further pressurizes the fuel, pressurized by the low-pressure pump, by a high-pressure pump that is driven according to an operating state of the internal combustion engine, and supplies the fuel pressurized by the high-pressure pump to a second fuel injection mechanism. The pulsation propagation suppressing unit is provided in at least one of the first fuel supply system and the second fuel supply system, and suppresses propagation of a pulsation generated in the high-pressure pump to the first fuel injection mechanism.

Abstract: In a V-type 8-cylinder engine in which the torque for rotating an intake camshaft is higher when intake valves of a #1 cylinder and a #3 cylinder in a left bank are closed, respective noses of a cam for opening and closing the intake valve of the #1 cylinder and a cam for opening and closing the intake valve of the #3 cylinder are each formed at a phase position displaced by X° (X>0) in the advance direction further from the phase position displaced in the advance direction by 90° with respect to the nose of a cam for opening and closing the intake valve of a cylinder fired after a delay of 180° in crank angle.

Abstract: An engine ECU executes a program including the steps of: detecting an engine speed NE, engine load, and engine coolant temperature (S100, S110, S115); when determination is made of being in an idle region (YES at S120), determining whether in a cold idle region, a transitional region, or a warm idle region (S130); injecting fuel from an intake manifold injector alone when in the cold idle region (S140); injecting fuel from the intake manifold injector and injecting fuel from an in-cylinder injector at the feed pressure when in the transitional region (S150); and injecting fuel from the in-cylinder injector at the feed pressure when in the warm idle region (S160).

Abstract: An auxiliary fuel injection unit includes two surge tanks partitioned by a wall surface, a butterfly valve for switching between connection and disconnection of two surge tanks, and one auxiliary fuel injection valve for injecting an auxiliary fuel in a direction opposing a direction of flow of intake air within the surge tank. The butterfly valve has a valve plate surface closing an opening provided in the surge tank wall surface and a rotation shaft for turning the plate surface. The auxiliary fuel injection valve has two injection holes connecting with each other, for injecting the auxiliary fuel toward the valve plate surface of the butterfly valve and toward the surge tank wall surface.

Abstract: An engine ECU executes a program including the steps of: detecting an engine speed NE, a throttle angle THA and an amount of intake air GA; estimating an amount of intake air GAINI from the engine speed NE and the throttle angle THA; if the estimated amount of intake air GAINI minus the detected amount of intake air GA is larger than a predetermined deviation ?GA(0) (YES at S104), then causing an intake manifold injector to inject fuel to clear a deposit, as controlled, at the exhaust stroke when an intake valve is closed and at the intake stroke when the intake valve is opened and an exhaust valve is closed.

Abstract: An ECU executes a program including the steps of: calculating a base timing of injection (INJB); determining whether an engine knocks; if the engine knocks, increasing a correction value INJK(I) applied to correct a timing of injection; and calculating the base timing of injection INJB plus the correction value INJK(I) to obtain a timing of injection INJ.

Abstract: An internal combustion engine includes an in-cylinder injection valve and an intake port injection valve. An ECU controls the fuel injection valves in a fuel injection mode that corresponds to an operational state of the engine. When deterioration of the combustion state is detected while the engine operational state is in a predetermined operational region where fuel is injected at least from the in-cylinder injection valve, the ECU switches the fuel injection mode such that the ratio of the amount of fuel injected from the in-cylinder injection valve to the entire amount of fuel supplied to the cylinder is decreased. As a result, the engine combustion state is prevented from deteriorating while suppressing noise generated in the fuel pressurizing and supplying system.

Abstract: An electronic control for determining knocking in an internal combustion engine having an intake injector for injecting fuel into an air intake port and an in-cylinder injector for directly injecting fuel into a combustion chamber. Knocking is determined based on an output signal from a knock sensor during a knock determination period. The electronic control unit alters the knock determination period in accordance with the ratio of the amount of fuel injected by the two injectors.

Abstract: A fuel injection device for an engine includes a direct injector and an intake passage injector. When the engine load is relatively low, a fuel pressure lowering procedure is executed for lowering the pressure of fuel supplied to the direct injector. An ECU sets a fuel injection ratio, which is the ratio between the fuel injection amount of the direct injector and that of the intake passage injector, based on the engine operation state. The ECU changes the fuel injection ratio such that the ratio of the fuel injection amount of the direct injector to the total amount of the fuel fed to a combustion chamber is decreased, until the pressure of the fuel supplied to the direct injector is raised from the value lowered through the fuel pressure lowering procedure to a predetermined permissible value. This effectively suppresses hampering of the engine combustion, caused by the lowered fuel pressure.

Abstract: An internal combustion engine includes an in-cylinder injection valve and an intake port injection valve. The engine is operated in a combustion mode that is selected from at least stratified lean combustion and homogeneous combustion. An ECU selects the combustion mode according to the operational state of the engine, and controls the fuel injection valves in a fuel injection mode that corresponds to the selected combustion mode. When a misfire is detected while the engine is operated in the stratified lean combustion or the homogeneous combustion, the ECU switches the fuel injection mode such that the ratio of the amount of fuel injected from the intake port injection valve to the entire amount of fuel supplied into the cylinder is increased. As a result, misfires are suppressed while preventing the fuel economy from deteriorating.

Abstract: A fuel injection device for an engine includes a direct injector and an intake passage injector. When the engine load is relatively low, a fuel pressure lowering procedure is executed for lowering the pressure of fuel supplied to the direct injector. An ECU sets a fuel injection ratio, which is the ratio between the fuel injection amount of the direct injector and that of the intake passage injector, based on the engine operation state. The ECU changes the fuel injection ratio such that the ratio of the fuel injection amount of the direct injector to the total amount of the fuel fed to a combustion chamber is decreased, until the pressure of the fuel supplied to the direct injector is raised from the value lowered through the fuel pressure lowering procedure to a predetermined permissible value. This effectively suppresses hampering of the engine combustion, caused by the lowered fuel pressure.

Abstract: When an inner wall of a cylinder head is viewed along an axis of a cylinder, a line that passes through a center of a fuel injection port and a center of a valve opening adjacent to the injection port is defined as a first line, and a line that is perpendicular to the first line is defined as a second line. A notch is formed in a part of the inner wall that defines the injection port. Specifically, when the inner wall is divided into sections by the second line, the notch is located in the section in which the adjacent opening exists. The notch is also displaced from the first line. Therefore, a sufficient thickness of the section corresponding to the valve seats of intake and exhaust valves are easily ensured.

Abstract: An auxiliary fuel injection unit includes two surge tanks partitioned by a wall surface, a butterfly valve for switching between connection and disconnection of two surge tanks, and one auxiliary fuel injection valve for injecting an auxiliary fuel in a direction opposing a direction of flow of intake air within the surge tank. The butterfly valve has a valve plate surface closing an opening provided in the surge tank wall surface and a rotation shaft for turning the plate surface. The auxiliary fuel injection valve has two injection holes connecting with each other, for injecting the auxiliary fuel toward the valve plate surface of the butterfly valve and toward the surge tank wall surface.