A fuel pressure control system for a fuel supply system of an injector of an engine includes: a booster pump for increasing a high-pressure system fuel pressure; a pressure reducing valve for reducing the high-pressure system fuel pressure; and a control device for controlling the booster pump and the pressure reducing valve. The control device includes a valve opening necessity determination unit for the pressure reducing valve. The control device executes a valve opening control for opening the pressure reducing valve. The control device further includes a restriction execution unit for performing a valve opening restriction control in the valve opening control to prevent a pressure exceeding a predetermined target portion threshold pressure from being applied to a target portion.

Methods and systems for operating an engine that includes two fuel pumps are described. In one example, a first fuel pump may be activated or remain activated in response to an engine shutdown request so that a second fuel pump may be cooled before the first fuel pump is deactivated in response to the engine shutdown request.

Methods and systems for operating an engine that includes two fuel pumps are described. In one example, a first fuel pump may be activated or remain activated in response to an engine shutdown request so that a second fuel pump may be cooled before the first fuel pump is deactivated in response to the engine shutdown request.

An engine control system for an engine includes: a pump control module configured to control a coolant pump; a block control module configured to control opening of a block valve; a fuel control module configured to control fueling of the engine; a coolant control module configured to control a position of a coolant valve; and an adjustment module configured to, when the coolant pump is pumping, the block valve is open, and the coolant valve is positioned such that an input is connected to an output, adjust the fueling of the engine such that fueling of the engine is fuel rich.

A method for monitoring a pressure sensor in a direct injection system including at least one common rail, a high-pressure fuel pump, a hydraulic circuit connecting the high-pressure pump to the common rail, a passive pressure-limiting valve connected to the hydraulic circuit, configured to open once the pressure in the hydraulic circuit is greater than a threshold pressure, so as to discharge the fuel, including the steps of detecting the opening of the pressure-limiting valve, measuring the pressure P.sub.MES corresponding to the time of opening of the pressure-limiting valve and comparing the measured pressure P.sub.MES to the threshold pressure P.sub.1 in order to detect a drift in the pressure sensor.

A method for monitoring a pressure sensor in a direct injection system including at least one common rail, a high-pressure fuel pump, a hydraulic circuit connecting the high-pressure pump to the common rail, a passive pressure-limiting valve connected to the hydraulic circuit, configured to open once the pressure in the hydraulic circuit is greater than a threshold pressure, so as to discharge the fuel, including the steps of detecting the opening of the pressure-limiting valve, measuring the pressure P.sub.MES corresponding to the time of opening of the pressure-limiting valve and comparing the measured pressure P.sub.MES to the threshold pressure P.sub.1 in order to detect a drift in the pressure sensor.

A method includes detecting a change in a loading condition on an engine based on use of an implement system including a pump driven by the engine, an actuator fluidly coupled to the pump, and an implement repositionable with the actuator. The change in the loading condition is detected based on a variation in a command signal from a joystick that controls movement of the implement, an outlet pressure of the pump, a displacement of the pump, and/or an engagement signal of a clutch positioned to selectively couple the pump to the engine. The method further includes commanding a fueling system to increase an amount of fuel provided to the engine and/or an air handling system of the machine to increase an amount of air and/or a boost pressure of the air provided to the engine in response to detection of an increasing loading condition based on the variation.

A method includes detecting a change in a loading condition on an engine based on use of an implement system including a pump driven by the engine, an actuator fluidly coupled to the pump, and an implement repositionable with the actuator. The change in the loading condition is detected based on a variation in a command signal from a joystick that controls movement of the implement, an outlet pressure of the pump, a displacement of the pump, and/or an engagement signal of a clutch positioned to selectively couple the pump to the engine. The method further includes commanding a fueling system to increase an amount of fuel provided to the engine and/or an air handling system of the machine to increase an amount of air and/or a boost pressure of the air provided to the engine in response to detection of an increasing loading condition based on the variation.

An engine control system for an engine includes: a pump control module configured to control a coolant pump; a block control module configured to control opening of a block valve; a fuel control module configured to control fueling of the engine; a coolant control module configured to control a position of a coolant valve; and an adjustment module configured to, when the coolant pump is pumping, the block valve is open, and the coolant valve is positioned such that an input is connected to an output, adjust the fueling of the engine such that fueling of the engine is fuel rich.

A variable combustion cylinder ratio control method variably controls a combustion cylinder ratio of an engine during an intermittent deactivation operation, in which cylinder deactivation is intermittently performed. The method includes, when setting N to an integer greater than or equal to 1, repeatedly performing a cylinder deactivation in a pattern in which combustion is consecutively performed in N cylinders in the order of cylinders entering a combustion stroke, and then a subsequent cylinder is deactivated. The method further includes changing the combustion cylinder ratio by changing the pattern such that the value of N is changed by one at a time.