A pump unit includes a pump housing having a low-pressure inlet and a high-pressure outlet. A working medium is fed via the low-pressure inlet to a working chamber formed in the pump housing. The working medium is discharged from the working chamber via the high-pressure outlet. The pump unit also includes a pump piston channel formed in the pump housing and having a longitudinal axis. The pump unit has a first pump piston arranged movably along the longitudinal axis in the pump piston channel and coupled hydraulically to the working chamber. The pump unit also has a second pump piston arranged movably along the longitudinal axis in the pump piston channel and coupled hydraulically via a compensation volume to the first pump piston, wherein the compensation volume is coupled hydraulically to a compensation unit configured to adapt the compensation volume based on a pressure in the working chamber.

A direct injection injector injects all of fuel having an idle required fuel amount required for an idle operation and makes a port injection injector inject no fuel from a second time to a third time so that an internal combustion engine executes idle operation from second time to third time. A fuel cut operation in which the fuel is not injected from both the direct injection injector and the port injection injector is executed from third time so that operation of the internal combustion engine is stopped at or after third time. At least one of the direct injection injector and the port injection injector inject the fuel so that operation of the internal combustion engine is restarted when a predetermined engine restart condition is satisfied under a state where operation of the internal combustion engine is stopped at or after third time.

The application is directed to a diesel engine. If the rack cannot complete a predetermined operation within a predetermined amount of time due to the key switch being held at a start-position, the control unit controls a starter to cause a plunger to perform a preparatory stroke operation, and the stroke operation by the plunger is stopped before the diesel engine starts.

According to one aspect of the present disclosure, a method of controlling a common rail fuel system of an engine system is provided. The common rail fuel system includes a fuel pump, a fuel rail, a plurality of fuel injectors, and a pressure-responsive relief valve fluidly coupled to the fuel rail. The method comprises identifying a pressure condition of the fuel rail indicative of the pressure-responsive relief valve being in an open and latched condition, the identification being based on detecting a rise and reduction in rail pressure within a threshold time period. The method further comprises terminating flow from the fuel pump, while the common rail fuel system is operating, to unlatch and close the pressure-responsive relief valve.

Disclosed herein is a diesel ISG vehicle, including an engine ECU controlling a rail pressure of a common rail engine system, in which the engine ECU determines a cold start of the engine based on detected cooling water temperature and detected fuel temperature at the time of engine restarting by idle go of the idle stop & go (ISG) and then restarts the engine by a quick rail pressure control mode in which the pressure of the fuel pumped to a common rail is controlled or restarts the engine by a normal rail pressure control mode in which the flow rate and the pressure of the fuel is controlled, thereby improving the fuel efficiency by the ISG restarting which does not increase a driving torque of a high pressure pump, particularly, reducing a fuel injection quantity by reduction in a loss of accessories such as pump and compressor.

A fuel pump for conveying fuel includes a conveying unit having a cylinder, a plunger received in the cylinder, a pump spring received in the cylinder, an inner sleeve connected to the plunger, an outer sleeve in contact with the pump spring and in contact with a roller of a cam mechanism, and a locking bolt configured to detachably connect the inner and outer sleeves.

According to one aspect of the present disclosure, a method of controlling a common rail fuel system of an engine system is provided. The common rail fuel system includes a fuel pump, a fuel rail, a plurality of fuel injectors, and a pressure-responsive relief valve fluidly coupled to the fuel rail. The method comprises identifying a pressure condition of the fuel rail indicative of the pressure-responsive relief valve being in an open and latched condition, the identification being based on detecting a rise and reduction in rail pressure within a threshold time period. The method further comprises terminating flow from the fuel pump, while the common rail fuel system is operating, to unlatch and close the pressure-responsive relief valve.

Disclosed herein is a diesel ISG vehicle, including an engine ECU controlling a rail pressure of a common rail engine system, in which the engine ECU determines a cold start of the engine based on detected cooling water temperature and detected fuel temperature at the time of engine restarting by idle go of the idle stop & go (ISG) and then restarts the engine by a quick rail pressure control mode in which the pressure of the fuel pumped to a common rail is controlled or restarts the engine by a normal rail pressure control mode in which the flow rate and the pressure of the fuel is controlled, thereby improving the fuel efficiency by the ISG restarting which does not increase a driving torque of a high pressure pump, particularly, reducing a fuel injection quantity by reduction in a loss of accessories such as pump and compressor.