Abstract: An engine exhaust controlling device is provided, including a controller for detecting whether or not a request is present for activating a catalyst when the engine is started, and whether or not a fuel pressure meets or exceeds a predetermined pressure. When a request is not present, the engine is operated in a homogeneous combustion mode in which fuel is injected during the intake stroke and ignition occurs before compression top dead center. When a request is present, an intake valve characteristic is adjusted to be larger than when the request is not present. If the fuel pressure is not greater than or equal to the predetermined fuel pressure, the engine is operated in the homogeneous combustion mode, otherwise, the engine is operated in a retarded combustion mode in which the ignition timing is retarded to ignite the fuel-air mixture after compression top dead center.

Abstract: A variable valve controller for internal combustion engines and methods for operating the same. In the variable valve controller, and engine control unit (ECM) calculates a target value of a valve lift (VEL) for an intake valve and transmits it to a controller with a second control unit (VEL-C/U). The VEL-C/U controls the VEL on the basis of the VEL target value, detects a VEL actual value, and transmits it to the ECM. The ECM calculates a target value of a valve timing (VTC), and controls the VTC. Also, the ECM controls a limit value for the VTC target value in accordance with the VEL actual value. Fail-safe control is performed when an error occurs in a communication unit or a sensor. To reliably perform the control in a period from occurrence of an error to detection of the error, the limit value is set with calculation by offsetting a limit basic value set in accordance with the VEL actual value, by a displacement of the VEL within a time necessary for detecting the error.

Abstract: An engine exhaust controlling device is provided, including a controller for detecting whether or not a request is present for activating a catalyst when the engine is started, and whether or not a fuel pressure meets or exceeds a predetermined pressure. When a request is not present, the engine is operated in a homogeneous combustion mode in which fuel is injected during the intake stroke and ignition occurs before compression top dead center. When a request is present, an intake valve characteristic is adjusted to be larger than when the request is not present. If the fuel pressure is not greater than or equal to the predetermined fuel pressure, the engine is operated in the homogeneous combustion mode, otherwise, the engine is operated in a retarded combustion mode in which the ignition timing is retarded to ignite the fuel-air mixture after compression top dead center.

Abstract: A variable valve controller for internal combustion engines and methods for operating the same. In the variable valve controller, and engine control unit (ECM) calculates a target value of a valve lift (VEL) for an intake valve and transmits it to a controller with a second control unit (VEL-C/U). The VEL-C/U controls the VEL on the basis of the VEL target value, detects a VEL actual value, and transmits it to the ECM. The ECM calculates a target value of a valve timing (VTC), and controls the VTC. Also, the ECM controls a limit value for the VTC target value in accordance with the VEL actual value. Fail-safe control is performed when an error occurs in a communication unit or a sensor. To reliably perform the control in a period from occurrence of an error to detection of the error, the limit value is set with calculation by offsetting a limit basic value set in accordance with the VEL actual value, by a displacement of the VEL within a time necessary for detecting the error.

Abstract: A fuel properties estimating apparatus for an internal combustion engine includes a controller. The controller is configured to determine an estimated component concentration of a component, such as alcohol, in a fuel for the engine in accordance with an actual air fuel ratio of the engine, and to perform a plurality of estimating operations to determine the estimated component concentration at predetermined timings after an engine start of the engine.

Abstract: An internal exhaust gas recirculation amount estimation system calculates an in-cylinder temperature at an exhaust valve closure timing, an in-cylinder pressure at the exhaust valve closure timing, and a gas constant corresponding to a change in a composition of exhaust gas, based on an air-fuel mixture ratio. An exhaust valve closure timing in-cylinder residual gas amount is calculated based on at least the in-cylinder temperature, the in-cylinder pressure, and the gas constant. Also calculated is a valve overlap period blow-back gas amount, which is defined as a quantity of gas flow from one of intake and exhaust ports via a combustion chamber to the other port during a valve overlap period. An internal exhaust gas recirculation amount is calculated based on the exhaust valve closure timing in-cylinder residual gas amount and the valve overlap period blow-back gas amount.

Abstract: A fuel properties estimating apparatus for an internal combustion engine includes a controller. The controller is configured to determine an estimated component concentration of a component, such as alcohol, in a fuel for the engine in accordance with an actual air fuel ratio of the engine, and to perform a plurality of estimating operations to determine the estimated component concentration at predetermined timings after an engine start of the engine.

Abstract: An internal exhaust gas recirculation amount estimation system calculates an in-cylinder temperature at an exhaust valve closure timing, an in-cylinder pressure at the exhaust valve closure timing, and a gas constant corresponding to a change in a composition of exhaust gas, based on an air-fuel mixture ratio. An exhaust valve closure timing in-cylinder residual gas amount is calculated based on at least the in-cylinder temperature, the in-cylinder pressure, and the gas constant. Also calculated is a valve overlap period blow-back gas amount, which is defined as a quantity of gas flow from one of intake and exhaust ports via a combustion chamber to the other port during a valve overlap period. An internal exhaust gas recirculation amount is calculated based on the exhaust valve closure timing in-cylinder residual gas amount and the valve overlap period blow-back gas amount.