A method includes operating a spark ignition engine and flowing low pressure exhaust gas recirculation (EGR) from an exhaust to an inlet of the spark ignition engine. The method includes interpreting a parameter affecting an operation of the spark ignition engine, and determining a knock index value in response to the parameter. The method further includes reducing a likelihood of engine knock in response to the knock index value exceeding a knock threshold value.

Systems and methods are provided for cooling an overheated engine using a combination of variable displacement engine (VDE) technology and direct injection technology. In one example, a method may include deactivating a subset of engine cylinders based on an engine temperature and directly injecting liquid fuel into the deactivated cylinders. In this way, an increased thermal conductivity of the liquid fuel compared to air decreases the engine temperature at a faster rate than when air-based engine cooling methods are used, thereby preventing overheating-related engine degradation.

A CPU performs a regeneration process of stopping combustion control in one or some of cylinders and making the air-fuel ratio of an air-fuel mixture in the other cylinders or cylinder richer than a theoretical air-fuel ratio, when the amount of PM collected by a GPF increases. In performing the regeneration process, the CPU itself compensates for a fall in the output of an internal combustion engine by gradually increasing the filling efficiency of the other cylinders or cylinder. It should be noted, however, that since the output of the internal combustion engine temporarily fluctuates, the CPU compensates for the fluctuations through the use of a second motor-generator. The CPU varies the retardation amount of a timing of starting the regeneration process with respect to a timing of gradually increasing the filling efficiency, in accordance with the state of a battery.

Provided is an air leading type stratified scavenging two-stroke internal combustion engine including an air passage configured to allow supply of air to a scavenging passage configured to allow communication between a crank chamber and a combustion chamber, at least one sensor configured to detect an operating condition of an engine, and a fuel valve configured to control fuel supply to the air passage based on detection performed by the at least one sensor. The fuel supply to the air passage is controlled by the fuel valve at times other than start and idling of the engine or at needed times in addition to the start or the idling of the engine.

A system is provided for controlling engine fueling and includes an internal combustion engine, a fuel source, means for delivering fuel from the fuel source to the engine, and a controller configured to control the fuel delivering means according to a first operational mode so that, upon attaining a predetermined operational state of the engine, an amount of fuel delivered to the engine per unit time is kept constant. The system will typically but not necessarily be provided in a vehicle such as a truck or a passenger automobile. A method for controlling engine fueling is also provided.

A method and system for operating a vehicle that includes an automatic transmission with a torque converter clutch is described. In one example, the method includes predicting a time that the torque converter clutch will open so that stopping rotation of the engine may be requested before the torque converter clutch is opened. The stopping rotation of the engine is requested to conserve fuel.

Systems and methods for operating an engine that is started via expansion stroke combustion are described. In one example, the method increases air flow through the engine during an engine stopping process so that a larger amount of air may be trapped in a cylinder that is on its expansion stroke so that greater amounts of engine torque may be provided during engine starting.

Methods, systems and devices for evaluating incoming air to an engine, industrial controller including engine controls, valves and solenoids, for concentrations of explosive or combustible gases or vapors, and actuating process control including but not limited to shutting down an engine or other industrial process to control an outcome including the prevention of an overspeed condition when pre-set or calculated elevated gas or vapor concentrations are detected. In some embodiments industrial control including engine shutdown may be achieved conventionally via an electronic kill signal, a shutdown of the fuel injector, carburetor or fuel pump, and in emergency conditions by the shutoff of incoming air to an air intake, turbocharger, or other air delivery systems. Decisions based on explosive gas or vapor concentrations and species and the use of networking to allow additional systems to take action before explosive gases or vapors reach said other valve-sensor devices can provide additional safety.

A control unit configured to control an electric turbocharger and an EGR valve. While an internal combustion engine is stopped, an oxygen-free period, which is a period during which oxygen surrounding an exhaust gas purifier used for an oxidation reaction runs out, is estimated based on a temperature of the exhaust gas purifier. Before entering the oxygen-free period, the EGR valve is opened and the electric turbocharger is driven. Air surrounding the exhaust gas purifier is replaced with fresh air. After replacement with the fresh air has been completed, the electric turbocharger is stopped.

An engine diagnostic system includes a control system having a controller operatively connected to an engine. A monitoring system has a sensor operatively connected to the engine. A diagnostic system is operatively connected to the engine. The diagnostic system is configured to implement a sensor diagnostic procedure that includes a sensor health test. The sensor health test includes comparing a measured value of a sensor to an expected value and determining the health of the sensor based on the difference between the measured value and the expected value. The sensor diagnostic procedure can also include telematics data analysis.