A system and method for a variable displacement internal combustion engine using different types of pneumatic cylinder springs on skipped working cycles to control engine and aftertreatment system temperatures are described. The system and method may be used to rapidly heat up the aftertreatment system(s) and/or an engine block of the engine following a cold start by using one or more different types of pneumatic cylinder springs during skipped firing opportunities. By rapidly heating the aftertreatment system(s) and/or engine block, noxious emissions such as hydrocarbons, carbon monoxide, NO.sub.x and/or particulates, following cold starts are significantly reduced.

Systems and methods for operating an internal combustion engine that is included in a hybrid vehicle are described. In one example, the internal combustion engine is operated in a two stroke mode during cold starting to increase mass flow to an electrically heated catalyst so that engine emissions may be reduced.

A split cycle internal combustion engine includes a combustion cylinder accommodating a combustion piston and a compression cylinder accommodating a compression piston. The engine also includes a controller arranged to receive an indication of a parameter associated with the combustion cylinder and/or a fluid associated therewith and to control an exhaust valve of the combustion cylinder in dependence on the indicated parameter to cause the exhaust valve to close during the return stroke of the combustion piston, before the combustion piston has reached its top dead centre position (TDC), when the indicated parameter is less than a target value for the parameter; and close on completion of the return stroke of the combustion piston, as the combustion piston reaches its top dead centre position (TDC), when the indicated parameter is equal to or greater than the target value for the parameter.

If an engine coolant temperature is equal to or lower than a first low-temperature determination value and a battery temperature is equal to or lower than a second low-temperature determination value when a request to start up an engine is made, the advancement driving of a variable valve operating mechanism is first started. Then, when an advancement amount of the variable valve operating mechanism later becomes equal to or larger than a prescribed startup start determination value, is started.

Methods and systems are provided for diagnosing degradation of a variable oil pump (VOP). In one example, a method may include during a deceleration fuel shut-off (DFSO) condition, diagnosing degradation of the VOP based on a rotational speed of the engine.

An assembly for an engine includes a control module including a controller operable to control at least certain aspects of the operation of the engine, a display including an input connected to the controller, and a wireless receiver connected to the controller. The wireless receiver is arranged to receive a signal from a wireless device to cause the controller to send an engine start signal to cause starting of the engine and wherein the input when actuated causes the controller to send an engine start signal to cause starting of the engine. In at least some implementations, no keyed ignition switch is provided to start the engine and the engine is started only via the wireless device or the input.

A method and system for operating a vehicle that includes an integrated starter/generator and a driveline disconnect clutch is described. In one example, the method estimates engine torque as a function of engine temperature during cold engine starts so that if an estimate of engine torque is in error, the integrated starter/generator may still successfully start the engine.

A gasoline compression ignition engine is operated in two modes. In a one mode of operation the engine is operated with a firing fraction of one, corresponding to all of the cylinders being active, working cylinders. In a second skip fire mode of operation a firing fraction of less than one may be used under conditions, such as a low load condition, to improve efficiency. The skip fire mode of operation may also be selected in part based on other considerations, such as maintaining an exhaust temperature conducive for efficient catalytic converter operation or limiting cylinder output variability.

A microcomputer determines that an abnormality has occurred in calculation functions regarding calculation of an injection amount command value and the like, based on a deviation of the injection amount command value, in an increasing manner, from a monitoring injection amount. The microcomputer calculates, based on a cooling fluid temperature of an engine, a start-up injection amount such that the start-up injection amount becomes smaller when the cooling fluid temperature is high than when the cooling fluid temperature is low, and uses the start-up injection amount as the injection amount command value immediately after the completion of start-up of the engine. Besides, the microcomputer uses the smaller one of a start-up injection amount calculated this time and a monitoring start-up injection amount calculated last time, as a monitoring start-up injection amount that is used as the aforementioned monitoring injection amount immediately after the completion of start-up of the engine.

Methods and systems are provided for conducting an evaporative emissions test diagnostic on a vehicle fuel system and evaporative emissions control system during engine-on conditions. In one example, a first fuel vapor storage device is separated from a second fuel vapor storage device by a one-way check valve, thus preventing loading of the first fuel vapor storage device during conditions such as refueling operations, diurnal temperature fluctuations, or from running-loss vapors from a vehicle fuel tank. In this way, the evaporative emissions test diagnostic may be conducted during a cold-start event where an exhaust catalyst is below a predetermined threshold temperature required for catalytic oxidation of hydrocarbons in the engine exhaust, without increasing undesired exhaust emissions.