A control device of an internal combustion engine is provided. In the case where a switch request for switching from all-cylinder operation to partial-cylinder operation is made, before a switch from the all-cylinder operation to the partial-cylinder operation is executed, an intake air amount increase control increasing an intake air flow rate of an engine by increasing an opening degree of a throttle valve is performed, an ignition timing retardation control retarding an ignition timing is performed, and based on a retardation limit value of the ignition timing at a time point when the switch request is made, a start timing of the intake air amount increase control is changed. As a retardable amount being a difference between an initial ignition timing and the retardation limit value decreases, the start timing of the intake air amount increase control is delayed further.

A method for detecting the anti-knocking capacity of a fuel in an internal combustion engine, which comprises the step of analyzing the single combustion cycles of the cylinders to be repeated until a counter reaches a respective threshold value; the step of calculating the mean spark advance operated by the internal combustion engine in the single combustion cycles of the cylinders that have allowed said counter to reach the respective threshold value; and the step of determining the anti-knocking capacity of the fuel as a function of the first counter that has reached the respective threshold value and as a function of the mean spark advance operated by the internal combustion engine in the single combustion cycles of the cylinders that have allowed said counter to reach the respective threshold value.

Various systems and methods are described for controlling pre-ignition in a boosted engine in a newly manufactured vehicle. One method comprises, during a pre-delivery phase of the vehicle, operating the boosted engine in a pre-delivery calibration with a first, higher enrichment, in response to a pre-ignition event. The pre-delivery calibration is deactivated during a post-delivery phase and the boosted engine is operated with a second, lower enrichment in response to a pre-ignition event.

A controller includes a processor and a memory storing processor-executable instructions. The processor is programmed to receive a signal indicating engine knocking, adjust an octane requirement in response to the signal, and request a fuel for refueling meeting the octane requirement. The processor may also be programmed to avoid a gas station of most recent refueling in response to the signal and retard ignition timing of a spark plug in response to the signal.

Methods and systems are provided for adjusting an ignition timing of an internal combustion engine responsive to a biasing force of a pressure-reactive piston. In one example, an engine may include a pressure-reactive piston having a top wall biased away from a piston base by a pressure of gas contained within the base. An ignition timing of a combustion chamber including the piston is adjusted responsive to an estimated biasing force of the gas against the top wall.

An ignition timing control device for an internal combustion engine including: a setting unit configured to set a target ignition timing of the internal combustion engine based on a reference ignition timing and an advance correction amount; a start determination unit configured to determine, based on change in an alcohol concentration, whether or not the fuel injected from a fuel injection valve starts to switch from a first fuel to a second fuel higher in the alcohol concentration than the first fuel; a completion determination unit configured to determine whether or not switching to the second fuel is completed; a restriction unit configured to restrict the advance correction amount during a switching period to the advance correction amount corresponding to the alcohol concentration of the first fuel or lower; and a cancel unit configured to cancel restriction of the advance correction amount after the completion of the switching is determined.

Premixed engines including dual fuel engines can experience abnormal combustion characteristics including misfire, pre-ignition and knock. A method for detecting and mitigating abnormal combustion in an engine comprises sensing frequency components of an acoustic signal associated with a combustion chamber during a combustion cycle, the frequency components representative of at least one of a normal and an abnormal combustion characteristic; determining an in-cylinder pressure signal as a function of the acoustic signal; calculating as functions of the in-cylinder pressure signal at least one of a knock index, a gross indicated mean effective pressure and a start of combustion timing; detecting the abnormal combustion characteristic is at least one of (a) a misfire event when the gross indicated mean effective pressure is less than a predetermined mean effective pressure value; (b) a pre-ignition event when the start of combustion timing is advanced of a start of ignition timing; and (c) an engine knock event when the knock index is greater than a predetermined knock value; and performing a mitigation strategy for the detected abnormal combustion characteristic.

A controller includes a processor and a memory storing processor-executable instructions. The processor is programmed to receive a signal indicating engine knocking, adjust an octane requirement in response to the signal, and request a fuel for refueling meeting the octane requirement. The processor may also be programmed to avoid a gas station of most recent refueling in response to the signal and retard ignition timing of a spark plug in response to the signal.

An ignition timing control device for an internal combustion engine including: a setting unit configured to set a target ignition timing of the internal combustion engine based on a reference ignition timing and an advance correction amount; a start determination unit configured to determine, based on change in an alcohol concentration, whether or not the fuel injected from a fuel injection valve starts to switch from a first fuel to a second fuel higher in the alcohol concentration than the first fuel; a completion determination unit configured to determine whether or not switching to the second fuel is completed; a restriction unit configured to restrict the advance correction amount during a switching period to the advance correction amount corresponding to the alcohol concentration of the first fuel or lower; and a cancel unit configured to cancel restriction of the advance correction amount after the completion of the switching is determined.

A knocking detector is to detect knocking in the internal combustion engine in which a low-octane fuel is injected into a cylinder and a high-octane fuel whose octane number higher than an octane number of the low-octane fuel is injected into an inlet port. A knocking suppressor includes a first knocking suppressor and a second knocking suppressor. The first knocking suppressor is to increase a high-octane fuel ratio of an injection quantity of the high-octane fuel to a sum of an injection quantity of the low-octane fuel and the injection quantity of the high-octane fuel in order to suppress knocking in the internal combustion engine when the knocking detector detects the knocking. The second knocking suppressor is to suppress knocking of the internal combustion engine at a beginning of a period while the first knocking suppressor increases the high-octane fuel ratio.