During operation of the engine for a time period from a system-on operation to a system-off operation, the vehicle causes the warming-up determination parameter to be subject to addition when an engine is not in a flow path heat release state where an amount of heat released in the supply flow path is expected to be larger than an amount of heat received in the supply flow path, while causing the warming-up determination parameter to be subject to subtraction when the engine is in the flow path heat release state and a duration time of the flow path heat release state is equal to or longer than a first predetermined time period.

The invention is related to a fuel pressure control device for an internal combustion engine, which controls a pressure of fuel supplied to a fuel injection valve and includes: a fuel pump, adopting the internal combustion engine as a driving source, and discharging pressurized fuel to a side of the fuel injection valve; a boost control part, setting a fuel discharge amount of the high-pressure fuel pump to a maximum value for boosting a pressure from a time when cranking starts until a predetermined timing halfway during a startup of the internal combustion engine; and a limit control part, performing limit control which follows the boost control and limits the fuel discharge amount to an upper limit.

Electronic fuel injection for an internal combustion engine maintains an operator-specified air-to-fuel ratio during engine operations in high-speed, high-volume, mixed fuel applications. A microprocessor-based controller executes a program stored in memory to calculate a fuel flow value as a function of the specified air-to-fuel ratio and specified density ratio of mixed fuels. The controller outputs a control signal to a variable fuel flow relief valve and receives feedback from an engine fuel flow sensor. The controller adjusts the control signal until the feedback matches the fuel flow value. The program optimizes the fuel flow value by accounting for engine air flow, water vapor density, and dry air density effects in the calculation, based on signals received by the controller from various environmental sensors. The system has particular application in dragster engines that burn a mixture of nitromethane and methanol.

System for controlling an engine provided with an exhaust gas post-treatment system of the selective catalysis type, including a closed-loop control of NO.sub.x before the gas post-treatment system, according to the following steps: ⋅ a unit for determining a NO.sub.x setpoint in dependence on the rotational speed and the torque setpoint of the engine, ⋅ a unit for determining a NO value, and ⋅ a cascade control unit which is able to determine a setpoint for admitted oxygen and a correction of the supercharging pressure destined for unit for controlling the air loop of the engine as well as a correction of the injection pressure and a correction of the advance of the main injection in dependence on a NO.sub.x difference, between a NOx emission setpoint or corrected emission setpoint and a determined value of the quantity of NO.sub.x.

The invention relates to a method to control a fuel pump for a direct injection system of a heat engine provided with a common rail comprising the steps of determining a minimum threshold based on the pressure in the common rail and on the speed of the heat engine, on the temperature of the high-pressure pump and on the inlet pressure of the high-pressure pump; calculating the objective fuel flow rate to be fed by the high-pressure pump to the common rail instant by instant in order to have the desired pressure value inside the common rail; comparing the objective fuel flow rate with the minimum threshold; and controlling the high-pressure pump based on the comparison between the objective fuel flow rate and the minimum threshold.

A control system includes a controller. The controller estimates the swing-back amount indicating the turning amount of the crankshaft in the reverse rotation direction until the crankshaft stops. The controller calculates a stop-time counter value which is a value of a crank counter at the time when the engine is stopped based on a final counter value which is the value of the crank counter calculated last before the crankshaft stops and the estimated swing-back amount. The controller corrects the swing-back amount used for calculating the stop-time counter value based on a difference between the number of driving times calculated with reference to the map based on the calculated stop-time counter value and the value of the crank counter and the number of driving times calculated by increasing the number of driving times by one each time the high pressure system fuel pressure increases by the threshold or more.

A pressure detection unit detects a fuel pressure in high-pressure fuel passages. A drive control unit controls opening and closing of pressure adjusting valves based on a drive command signal output to the fuel injection valve. An acquisition unit acquires an inflection point of the fuel pressure detected by the pressure detection unit and an inclination of the fuel pressure after the inflection point appears, after an output of the drive command signal. A delay time computation unit computes a response delay time of the pressure adjusting valve with respect to the drive command signal for each of the first on-off valve and the second on-off valve based on the inflection point and the inclination acquired by the acquisition unit.

A method and system for correcting a fuel injection amount that injects fuel may include applying a current value for injecting a target fuel amount and injecting fuel under a driving condition in which fuel injection is blocked; determining a frequency analysis value for a pressure signal of the fuel pressure rail when the fuel is injected; determining a fuel amount difference corresponding to a difference value between the frequency analysis value and a reference frequency analysis value stored in a data storage in advance; and correcting a current value of the injector which is applied to inject the target fuel amount to remove the fuel amount difference.

Electronic fuel injection for an internal combustion engine maintains an operator-specified air-to-fuel ratio during engine operations in high-speed, high-volume, mixed fuel applications. A microprocessor-based controller executes a program stored in memory to calculate a fuel flow value as a function of the specified air-to-fuel ratio and specified density ratio of mixed fuels. The controller outputs a control signal to a variable fuel flow relief valve and receives feedback from an engine fuel flow sensor. The controller adjusts the control signal until the feedback matches the fuel flow value. The program optimizes the fuel flow value by accounting for engine air flow, water vapor density, and dry air density effects in the calculation, based on signals received by the controller from various environmental sensors. The system has particular application in dragster engines that burn a mixture of nitromethane and methanol.

Systems and methods are provided herein for tracking degradation of a high-pressure fuel pump. In one example, a fuel system controller is configured to receive an output pressure signal from a pressure sensor, transform the output pressure signal to the frequency domain to generate frequency content of the output pressure signal, and diagnose a condition of a fuel pump based at least in part on the frequency content of the output pressure signal, the fuel pump fluidly coupled to a fuel injector via a common fuel rail, and the fuel injector is operable to inject fuel to a cylinder of an engine.