Abstract: A method that protects a direct injection fuel injector in a multi-fuel engine comprises selectively operating the engine with at least one of a directly injected fuel introduced through the direct injection fuel injector and a second fuel. When fuelling the multi-fuel engine with the second fuel, a fuel system protection technique is selectively commanded when one or more adverse conditions, such as the direct injection fuel injector requiring cooling, is determined to exist. The fuel system protection technique comprises (a) suspending fuelling with the second fuel and injecting the directly injected fuel for a first predetermined number of engine cycles, and (b) switching back to fuelling the multi-fuel engine with the second fuel for a second predetermined number of engine cycles. The first and second predetermined number of engine cycles are selected to keep torque disturbances below a predetermined threshold value.

Abstract: A method that protects a direct injection fuel injector in a multi-fuel engine comprises selectively operating the engine with at least one of a directly injected fuel introduced through the direct injection fuel injector and a second fuel. When fuelling the multi-fuel engine with the second fuel, a fuel system protection technique is selectively commanded when one or more adverse conditions, such as the direct injection fuel injector requiring cooling, is determined to exist. The fuel system protection technique comprises (a) suspending fuelling with the second fuel and injecting the directly injected fuel for a first predetermined number of engine cycles, and (b) switching back to fuelling the multi-fuel engine with the second fuel for a second predetermined number of engine cycles. The first and second predetermined number of engine cycles are selected to keep torque disturbances below a predetermined threshold value.

Abstract: A control system for an engine includes a fuel mass determination module, a mass fraction determination module, and a fuel injector control module. The fuel mass determination module determines a first minimum fuel mass corresponding to a first fuel system of the engine. The mass fraction determination module determines first minimum and maximum mass fractions based on the first minimum fuel mass and a total fuel mass. The fuel injector control module limits a first desired mass fraction based on the first minimum and maximum mass fractions, and controls a first fuel injector of the engine based on the limited first desired mass fraction.

Abstract: A method for a multi-fuel vehicle includes: determining a first target amount of fuel to be injected for a combustion event of a combustion chamber of an engine; determining first and second fractions for the combustion event based on at least one of engine speed, engine load, and engine temperature; determining a second target amount of liquid fuel for the combustion event based on the first target amount and the first fraction; determining a third target amount of gaseous fuel for the combustion event based on the first target amount and the second fraction; selectively injecting a liquid fuel directly into the combustion chamber for the combustion event based on the second target amount and using a first fuel injector; and selectively injecting a gaseous fuel into a port of the combustion chamber for the combustion event based on the third target amount and using a second fuel injector.

Abstract: A system includes a voltage determination module and a fuel control module. The voltage determination module determines a first output voltage of a first oxygen sensor position upstream from a catalyst in an exhaust system of an engine, and determines a second output voltage from a second oxygen sensor positioned downstream from the catalyst, the first output voltage indicating a first oxygen level of exhaust upstream from the catalyst, the second output voltage indicating a second oxygen level of exhaust downstream from the catalyst. The fuel control module controls a fuel mass injected into the engine based on the first output voltage and the second output voltage when a temperature of the catalyst is greater than a light-off temperature, and controls the fuel mass based on the second output voltage and independent from the first output voltage when the catalyst temperature is less than light-off temperature.

Abstract: A method for a multi-fuel vehicle includes: determining a first target amount of fuel to be injected for a combustion event of a combustion chamber of an engine; determining first and second fractions for the combustion event based on at least one of engine speed, engine load, and engine temperature; determining a second target amount of liquid fuel for the combustion event based on the first target amount and the first fraction; determining a third target amount of gaseous fuel for the combustion event based on the first target amount and the second fraction; selectively injecting a liquid fuel directly into the combustion chamber for the combustion event based on the second target amount and using a first fuel injector; and selectively injecting a gaseous fuel into a port of the combustion chamber for the combustion event based on the third target amount and using a second fuel injector.

Abstract: A system according to the principles of the present disclosure includes a fuel mass module and a fuel control module. The fuel mass module determines a first fuel mass before the first fuel mass is injected into one of a cylinder of an engine and an injection port of the cylinder. The fuel mass module also determines a second fuel mass after injection of the first fuel mass starts. The fuel control module controls a first fuel injector to inject the first fuel mass into the one of the cylinder and the injection port for a combustion event. The fuel control module also controls a second fuel injector to inject the second fuel mass into one of the cylinder and the injection port for the combustion event. The second fuel injector is different from the first fuel injector.

Abstract: A control system for an engine includes a fuel mass determination module, a mass fraction determination module, and a fuel injector control module. The fuel mass determination module determines a first minimum fuel mass corresponding to a first fuel system of the engine. The mass fraction determination module determines first minimum and maximum mass fractions based on the first minimum fuel mass and a total fuel mass. The fuel injector control module limits a first desired mass fraction based on the first minimum and maximum mass fractions, and controls a first fuel injector of the engine based on the limited first desired mass fraction.

Abstract: A method and control module includes a control hold duty cycle module generating a control hold duty cycle signal and a voltage correction module generating a voltage correction signal. The control module also includes a correction module generating a corrected proportional correction signal based on a proportional correction signal and the voltage correction signal, and generating a corrected integral correction signal based on an integral correction signal and the voltage correction signal. The control module also includes a force determination module controlling a duty cycle to a phaser operator based upon the control hold signal, the corrected proportional correction signal and the corrected integral correction signal.

Abstract: A system includes a voltage determination module and a fuel control module. The voltage determination module determines a first output voltage of a first oxygen sensor position upstream from a catalyst in an exhaust system of an engine, and determines a second output voltage from a second oxygen sensor positioned downstream from the catalyst, the first output voltage indicating a first oxygen level of exhaust upstream from the catalyst, the second output voltage indicating a second oxygen level of exhaust downstream from the catalyst. The fuel control module controls a fuel mass injected into the engine based on the first output voltage and the second output voltage when a temperature of the catalyst is greater than a light-off temperature, and controls the fuel mass based on the second output voltage and independent from the first output voltage when the catalyst temperature is less than light-off temperature.

Abstract: A method and a control module for diagnosing an engine component function includes a comparison module comparing an in-cylinder pressure signal to a threshold and a fault indication module generating a diagnostic signal for an engine component in response to comparing.

Abstract: A diagnostic system includes a first pressure monitoring module, a second pressure monitoring module, and a fault determination module. The first pressure monitoring module determines low-lift pressures and high-lift pressures in a cam phaser when a first oil control valve (OCV) moves first valve lifters to the low-lift state and the high-lift state, respectively. The second pressure monitoring module determines low-lift pressures and high-lift pressures in the cam phaser when a second OCV moves second valve lifters to the low-lift state and the high-lift state, respectively. The fault determination module diagnoses a fault in one of the first OCV and the second OCV based the low-lift pressures and the high-lift pressures.

Abstract: A system includes a pressure signal adjustment module that generates a maximum pressure signal based on a fluid pressure signal from a pressure sensor of a camshaft phaser system of an engine. The pressure signal adjustment module detects a maximum peak value of the fluid pressure signal and maintains the maximum pressure signal at the maximum peak value for a peak and hold period. A diagnostic module detects a fault of the camshaft phaser system based on the maximum pressure signal during the peak and hold period.

Abstract: A diagnostic system includes a first pressure monitoring module, a second pressure monitoring module, and a fault determination module. The first pressure monitoring module determines low-lift pressures and high-lift pressures in a cam phaser when a first oil control valve (OCV) moves first valve lifters to the low-lift state and the high-lift state, respectively. The second pressure monitoring module determines low-lift pressures and high-lift pressures in the cam phaser when a second OCV moves second valve lifters to the low-lift state and the high-lift state, respectively. The fault determination module diagnoses a fault in one of the first OCV and the second OCV based the low-lift pressures and the high-lift pressures.

Abstract: A method and control module includes a control hold duty cycle module generating a control hold duty cycle signal and a voltage correction module generating a voltage correction signal. The control module also includes a correction module generating a corrected proportional correction signal based on a proportional correction signal and the voltage correction signal, and generating a corrected integral correction signal based on an integral correction signal and the voltage correction signal. The control module also includes a force determination module controlling a duty cycle to a phaser operator based upon the control hold signal, the corrected proportional correction signal and the corrected integral correction signal.

Abstract: A method and a control module for diagnosing an engine component function includes a comparison module comparing an in-cylinder pressure signal to a threshold and a fault indication module generating a diagnostic signal for an engine component in response to comparing.