An engine method, comprising delivering high octane fuel to a high octane fuel tank and delivering low octane fuel to a low octane fuel tank and injecting atmospheric air into an exhaust system for secondary air injection in response to delivering low octane fuel to an engine.

A apparatus for an engine, and the apparatus includes an ECU. The ECU is configured to (i) perform a feedback control such that the engine speed converges to a target speed by correcting ignition timing during the feedback control, (ii) make a determination that fuel supplied to the engine is a heavy fuel when an ignition fulfillment rate is equal to or greater than a predetermined threshold value within a predetermined period after the engine is started, the ignition fulfillment rate is a ratio of the advance correction amount of the ignition timing to a maximum ignition correction range, the maximum ignition correction range is a maximum range in which the ignition timing is corrected during the feedback control, and (iii) set the threshold value to a value that depends on a temperature representative value of the engine, the temperature representative value is correlated with the engine temperature.

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 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.

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.

Method for operating an internal combustion engine, wherein the internal combustion engine is operated by an air-fuel mixture comprising a fuel mixture and air, wherein the fuel mixture comprises a first fuel, preferably natural gas, and hydrogen as a second fuel different from the first fuel, wherein a hydrogen content of the fuel mixture is determined, and at least an ignition timing is adapted as a function of the hydrogen content of the fuel mixture independent of a target power output of the internal combustion engine,
wherein the higher the amount of hydrogen in the fuel mixture the later the ignition timing is set for at least partially compensating a shift of a center of combustion due to higher flame speed of hydrogen compared to the first fuel.

Method for operating an internal combustion engine, wherein the internal combustion engine is operated by an air-fuel mixture comprising a fuel mixture and air, wherein the fuel mixture comprises a first fuel, preferably natural gas, and hydrogen as a second fuel different from the first fuel, wherein a hydrogen content of the fuel mixture is determined, and at least an ignition timing is adapted as a function of the hydrogen content of the fuel mixture independent of a target power output of the internal combustion engine,
wherein the higher the amount of hydrogen in the fuel mixture the later the ignition timing is set for at least partially compensating a shift of a center of combustion due to higher flame speed of hydrogen compared to the first fuel.