Methods and systems are disclosed for operating an engine that includes a knock control system that may determine contributions of individual transient and steady-state noise sources to an engine background noise level. The contributions of the transient and steady-state individual noise sources may be the basis for establishing the presence or absence of knock in one or more engine cylinders.

Fuel injection control of an internal combustion engine requires an optimized fuel amount that can be burned completely with oxygen in intake air to be supplied, but the oxygen concentration in the atmospheric air is affected by humidity. By separately calculating a dry air flow rate that directly affects the oxygen amount and a humidity flow rate that is a change factor of the oxygen concentration in the intake air of the internal combustion engine, the fuel can be supplied to the cylinder of the internal combustion engine at an optimized air-fuel ratio. In addition, highly precise control involving EGR for flowback of a part of the exhaust gas flowing in the exhaust pipe to the intake pipe can also be achieved.

The present invention describes a fuel-management system for minimizing particulate emissions in turbocharged direct injection gasoline engines. The system optimizes the use of port fuel injection (PFI) in combination with direct injection (DI), particularly in cold start and other transient conditions. In the present invention, the use of these control systems together with other control systems for increasing the effectiveness of port fuel injector use and for reducing particulate emissions from turbocharged direct injection engines is described. Particular attention is given to reducing particulate emissions that occur during cold start and transient conditions since a substantial fraction of the particulate emissions during a drive cycle occur at these times. Further optimization of the fuel management system for these conditions is important for reducing drive cycle emissions.

Methods and systems are disclosed for operating an engine that includes a knock control system that may determine contributions of individual transient and steady-state noise sources to an engine background noise level. The contributions of the transient and steady-state individual noise sources may be the basis for establishing the presence or absence of knock in one or more engine cylinders.

A control apparatus configured to control a power unit of a vehicle includes an electronic control unit configured to i) store a set of measurement values of at least one physical parameter representing a plurality of conditions of the power unit; ii) approximate the stored set of the measurement values, by mixed probability distribution, so as to obtain a first probability distribution of the measurement values representing a first condition, and a second probability distribution of the measurement values representing a second condition; iii) set a discrimination boundary between values representing the first condition and values representing the second condition, between mean values of the first probability distribution and the second probability distribution; and iv) control the power unit, according to a result of comparison between a measurement value and the discrimination boundary.

A method to control a road vehicle provided with an internal combustion engine having a plurality of cylinders and with a servo-assisted transmission. The control method comprises the steps of: establishing a minimum spark advance which should not be exceeded in order to avoid the risk of knocking or spontaneous ignitions of the mixture; temporarily reducing, during a gear shift in the servo-assisted transmission, a torque generated by the internal combustion engine by setting an actual spark advance, which is smaller than the minimum spark advance, for one single thermodynamic cycle of each cylinder; and cancelling the injection of fuel into each cylinder in the thermodynamic cycle immediately following the thermodynamic cycle carried out with an actual spark advance smaller than the minimum spark advance.

Systems and methods for restarting an engine are presented. In one example, spark timing during engine starting is adjusted in response to engine speed and a second control parameter. The second control parameter may be correlated with crankshaft or rod degradation. Spark may be advanced from minimum spark for best torque when engine speed is greater than desired and when the second control parameter does not provide an indication of engine degradation.

A control device for an internal combustion engine includes an air-fuel ratio controller to execute a stoichiometric operation in which an air-fuel ratio of an air-fuel mixture in a combustion chamber of the internal combustion engine is set to a stoichiometric air-fuel ratio and a lean operation in which the air-fuel ratio is set to an air-fuel ratio leaner than the stoichiometric air-fuel ratio. A ignition timing controller is to calculate at least one ignition timing control parameter based on a laminar combustion velocity and to control an ignition plug provided in the combustion chamber to ignite based on the at least one ignition timing control parameter in a transitional state between the stoichiometric operation and the lean operation.

Methods and systems are provided for operating a variable displacement engine that includes a knock control system. Fuel injection timing and cylinder firing patterns may be adjusted to maintain engine background noise levels so that the presence or absence of engine knock may be more reliably detected. Further, select variable engine displacement modes may be avoided so that engine background noise level changes may be reduced to improve engine knock detection.

Methods and systems are provided for operating a variable displacement engine that includes a knock control system. Engine background noise levels for detecting engine knock may be the basis for determining whether or not the engine is operating in a cylinder deactivation mode. Further, select variable engine displacement modes may be avoided so that engine background noise level changes may be reduced to improve engine knock detection.