The present invention relates generally to techniques for improving fuel efficiency of a vehicle powered by an internal combustion engine capable of operating at various displacement levels. An autonomous driving unit or cruise controller selects when possible an engine torque output that corresponds to a fuel efficient displacement level. The resultant vehicle speed profile and NVH level is acceptable to vehicle occupants.

A method for controlling a multi-cylinder combustion engine, wherein the combustion engine has a first operating state in which all cylinders are active, and a second operating state in which one of the multiple cylinders is active and one of the multiple cylinders is deactivated. The method comprises switching the combustion engine from the first to the second operating state, wherein, in the cylinder to be deactivated, an exhaust valve is deactivated after a combustion stroke and an intake valve is deactivated before an intake stroke following the combustion stroke in the closed state, and changing an ignition angle of the cylinder to be deactivated to an earlier ignition time and an optional change of the air/fuel mixture leads to a reduction in a temperature of an exhaust gas arising during the combustion stroke.

Methods, devices, controllers, and algorithms are described for operating an internal combustion engine wherein at least some firing opportunities utilize low temperature gasoline combustion (LTGC). Other firing opportunities may be skipped or utilize some other type of combustion, such as spark ignition. The nature of any particular firing opportunity is dynamically determined during engine operation, often on a firing opportunity by firing opportunity basis. Firings that utilize LTGC produce little, if any, nitrous oxides in the exhaust stream and thus, in some implementations, may require no aftertreatment system to remove them from the exhaust stream.

A system includes a control system configured to monitor operating conditions in at least a first cylinder of a reciprocating engine and to control the reciprocating engine, wherein the control system includes a first sensor configured to monitor a first type of operating condition of the first cylinder, and a controller communicatively coupled with the first sensor. The controller is configured to receive a first signal indicative of a first measurement of the first type of operating condition from the first sensor; analyze the first signal to detect a misfire condition in the first cylinder; derive an amount of residual gas in the first cylinder if the misfire condition is detected; and adjust control of the reciprocating engine based on the amount of residual gas.

One embodiment is a system comprising an internal combustion engine having one or more non-dedicated cylinders and one or more dedicated EGR cylinders configured to provide EGR to the engine via an EGR loop, a first spark plug coupled to each of the one or more non-dedicated cylinders, and a second spark plug coupled to each of the one or more dedicated EGR cylinders, wherein the second spark plug has a physical or dimensional characteristic that is different from the first spark plug. In certain forms each of the non-dedicated cylinders has only one of a first type of spark plug and each of the dedicated EGR cylinders has only one of a second type of spark plug. One or more of the characteristics that may vary between the first and second types of spark plugs include spark gap, electrode diameter, heat range, and ion sensing capability.

A internal combustion engine system includes a gasoline internal combustion engine having a set of donor cylinders and a set of non-donor cylinders. The donor cylinders provide a proportion of the exhaust gas to an exhaust gas recirculation system and the remainder of the exhaust gas to an exhaust gas aftertreatment system including a particulate filter. The non-donor cylinders also provide exhaust gas to exhaust gas aftertreatment system. An engine controller can determine whether the particulate filter needs regeneration, and in response, retard a spark timing of the non-donor cylinders by an amount that is different from an amount or retardation of the donor cylinders.

A control apparatus for an internal combustion engine includes an electronic control unit configured to i) perform a fuel introduction process, ii) calculate a total injection amount in the fuel introduction process, and control each of fuel injection valves based on a required injection amount per cylinder when the fuel introduction process is performed, and iii) perform a cylinder deactivation process for stopping fuel from being injected for one or some of cylinders, and controlling each of the fuel injection valves such that an amount of the fuel obtained by dividing the total injection amount is injected for a cylinder or cylinders other than the one or some of the cylinders for which the fuel is stopped from being injected, when the fuel introduction process is performed.

A controller for a vehicle includes a combustion stoppage period processor and a combustion period processor. The combustion stoppage period processor is configured to selectively execute one of a fuel cut process or a fuel feeding process when stopping combustion in the cylinder in a situation in which a crankshaft of the internal combustion engine is rotating. The combustion period processor is configured to execute an increase process that increases flow speed of exhaust gas in the exhaust pipe when the fuel feeding process is executed while combustion is stopped in the cylinder and then combustion is resumed in the cylinder in which the combustion has been stopped.

A control device for an engine includes a valve-stopping mechanism 14b which holds intake and exhaust valves 41, 51 of the first and the fourth cylinders (idle cylinders) of four cylinders in closed states, a throttle valve control unit 115, an ignition period control unit 113, and an ECU 110 which controls the valve-stopping mechanism 14b, the throttle valve control unit 115, and the ignition period control unit 113. The ECU 110 sets a retard amount of the ignition period of the idle cylinder behind the basic ignition period at least in starting the all-cylinder operation in accordance with an amount of burned gas existing in the idle cylinder in switching to the all-cylinder operation from the reduced-cylinder operation.

A method of adjusting operation of an internal combustion engine includes injecting fuel into cylinders of the internal combustion engine (first fuel operation); obtaining a first fuel exhaust temperature profile during the first fuel operation; injecting two fuels into the cylinders in a duel fuel operation; obtaining a duel fuel exhaust temperature profile; and adjusting the injection quantity and/or an injection timing of one fuel in a cylinder(s), based on a difference between the first fuel exhaust temperature profile and the duel fuel exhaust temperature profile. Other methods of operating with single fuel and using sensors other than exhaust temperature sensors are disclosed.