A system for determining properties of fuel supplied to an internal combustion (IC) engine and for adjusting operations of the IC engine based on the determined properties. The system includes an air-flow throttle configured to control the air supplied to the IC engine; a fuel-flow throttle configured to control the fuel supplied to the IC engine; and an engine control module (ECM) configured to receive readings from and control operation of the throttles. The ECM is configured to perform a fuel-air determination program where the ECM determines a percent-error air-to-fuel ratio (AF) based on a true AF ratio compared to an ideal AF ratio. The ECM is configured to perform a fuel property determination and adjustment program in which the ECM is configured to adjust operations of the IC engine based on a fuel property value determined using the percent-error AF ratio.

Methods and systems are provided for accurately determining the composition of a knock control fluid using sensors already present in the engine system. An intake oxygen sensor is used to estimate the water and the alcohol content of a knock control fluid that is direct injected into an engine cylinder responsive to an indication of abnormal combustion. A change in the pumping current of the oxygen sensor due to the water content of the knock control fluid is distinguished from a change in the pumping current of the oxygen sensor due to the alcohol content of the knock control fluid, while compensating for interfering effects of intake air diluents on the change in pumping current.

A marine drive system includes an engine, a fuel system that provides at least two different fuels to the engine, and a fuel selection means for selecting a fuel type. A control unit accesses a set of fuel-specific operating parameters based on the selected fuel type and controls the engine based on the set of fuel-specific operating parameters.

Methods and systems are presented for providing information to a vehicle driver allows the driver to make an informed decision regarding selecting higher or lower octane fuel to operate the vehicle. In one example, the driver is presented fuel cost per unit distance traveled based on operating the vehicle on higher octane fuel and lower octane fuel.

Methods and systems are provided for accurately determining the composition of a knock control fluid using sensors already present in the engine system. An intake oxygen sensor is used to estimate the water and the alcohol content of a knock control fluid that is direct injected into an engine cylinder responsive to an indication of abnormal combustion. A change in the pumping current of the oxygen sensor due to the water content of the knock control fluid is distinguished from a change in the pumping current of the oxygen sensor due to the alcohol content of the knock control fluid, while compensating for interfering effects of intake air diluents on the change in pumping current.

Methods and systems are provided for reducing late burn induced cylinder pre-ignition events. Forced entry of residuals from a late burning cylinder into a neighboring cylinder may be detected based on engine block vibrations sensed in a window during an open exhaust valve of the late burning cylinder. In response to the entry of residuals, a pre-ignition mitigating action, such as fuel enrichment or deactivation, is performed in the neighboring cylinder.

Methods and systems are provided for accurately determining the composition of a knock control fluid using sensors already present in the engine system. An intake or an exhaust oxygen sensor is used to estimate the water and the alcohol content of a knock control fluid that is direct injected into an engine cylinder responsive to an indication of abnormal combustion. A change in the pumping current of the oxygen sensor due to the water content of the knock control fluid is distinguished from a change in the pumping current of the oxygen sensor due to the alcohol content of the knock control fluid.

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 method for regulating an ignition time for combustion processes of an internal combustion engine includes determining an ignition angle for a combustion process as a function of an operating parameter of the internal combustion engine, based on a characteristic diagram and as a function of a knocking limit offset.