Method for operating a common rail injection arrangement for an internal combustion engine have a stop-start system

Patent metadata

Field	Value
Publication number	US-2016245220-A1
Application number	US-201615053766-A
Country	US
Kind code	A1
Filing date	Feb 25, 2016
Priority date	Feb 25, 2015
Publication date	Aug 25, 2016
Grant date	—

Abstract

Methods and system are provided for operating a fuel system of a stop-start engine system. In one example a method may comprise powering off a lift pump and maintaining a volume control valve in a closed position during an engine stop to maintain a fuel pressure within a fuel rail and one or more fuel injectors. The method may further comprise, in response to determining an engine start is desired, powering on the lift pump, initiating cylinder combustion, and operating a higher pressure pump (HPP) in an unpressurized mode when a fuel pressure upstream of the HPP is less than a threshold and switching to operating the HPP in a pressurized mode when the fuel pressure upstream of the HPP reaches the threshold.

First claim

1 . A method for operating a common rail injection arrangement, which is provided for an internal combustion engine having a stop-start system and which comprises a pre-supply pump, connected to a high-pressure pump in a manner which allows fluid transfer, and a manifold, connected to the high-pressure pump in a manner which allows fluid transfer, as well as at least one injection nozzle, connected to the manifold in a manner which allows fluid transfer, wherein the pre-supply pump is kept active when the internal combustion engine is in operation, the method comprising:
initiating a stop phase by putting the running internal combustion engine and the high-pressure pump out of operation, wherein the pre-supply pump is switched to the inactive state; initiating a starting phase for the out-of-operation internal combustion engine, wherein the high-pressure pump is operated at least temporarily in an unpressurized state before or during the starting phase of the internal combustion engine, while the pre-supply pump is switched to the active state and delivers fuel to the high-pressure pump and builds up pre-supply pressure; operating the high-pressure pump to maintain and/or increase the pressure within the common rail injection arrangement, when a pre-supply pressure increases above a threshold; and starting the internal combustion engine by cranking the engine and injecting fuel into a combustion chamber of the internal combustion engine with the aid of the pressure provided within the common rail injection arrangement.

2 . The method of claim 1 , wherein the common rail injection arrangement is at least partially closed by at least one shutoff valve to maintain the pressure within said arrangement.

3 . The method of claim 1 , wherein the common rail injection arrangement comprises a volume control valve, the volume control valve connected to the high-pressure pump in a manner which allows fluid transfer and is closed in conjunction with the stop phase of the internal combustion engine.

4 . The method of claim 3 , where the operating the high-pressure pump in the unpressurized state comprises closing the volume control valve.

5 . The method of claim 1 , further comprising, switching on the pre-supply pump before starting the engine and putting the high-pressure pump into operation to increase an initial pressure within the high-pressure pump.

6 . The method of claim 1 , further comprising, switching on the pre-supply pump while operating the high-pressure pump in the unpressurized manner when starting the internal combustion engine, to increase an initial pressure within the high-pressure pump.

7 . A system for a common rail injection arrangement of a stop-start engine, the system comprising:
a high-pressure fuel pump; a pre-supply pump, connected to a high-pressure fuel pump in a manner which allows fluid transfer, wherein the pre-supply pump is kept active when the internal combustion engine is in operation; a manifold, connected to the high-pressure pump in a manner which allows fluid transfer; at least one injection nozzle, connected to the manifold in a manner which allows fluid transfer; and a controller with computer readable instructions stored in non-transitory memory for: initiating a stop phase by putting the running internal combustion engine and the high-pressure pump out of operation, wherein the pre-supply pump is also switched to the inactive state; maintaining, within the common rail injection arrangement, a pressure built up by the high-pressure pump during the operation of the internal combustion engine, wherein the pre-supply pump is simultaneously kept inactive; initiating a starting phase for the out-of-operation internal combustion engine, wherein the pre-supply pump is switched to an active state; starting of the internal combustion engine by cranking the latter and at least partial injection of fuel into a combustion chamber of the internal combustion engine with the aid of the pressure maintained within the common rail injection arrangement, wherein the high-pressure pump is operated at least temporarily in an unpressurized state during the starting; and switching the high-pressure pump into a pressurized state to maintain and/or increase the pressure within the common rail injection arrangement, in response to a pre-supply pressure increasing above a threshold to continue supplying the running internal combustion engine with fuel.

8 . The system of claim 7 , wherein the controller further includes instructions for powering on the pre-supply pump in the active state.

9 . A method for a stop-start engine comprising:
during an engine stop: powering off a lift pump; and in response to determining that an engine start is desired: powering on the lift pump; initiating cylinder combustion; and operating a higher pressure pump (HPP) in an unpressurized mode; and switching the HPP to a pressurized mode in response to fuel pressure upstream of the HPP reaching a threshold.

10 . The method of claim 9 , further comprising during the engine stop, closing a volume control valve positioned between the HPP and the lift pump to stop supplying fuel the HPP, where in the closed position of the volume control valve, substantially no fuel flows flow there-through.

11 . The method of claim 9 , further comprising during the engine stop, opening an inlet valve positioned between the lift pump and a single pressure chamber of the HPP for regulating fuel flow there-between to permit fuel flow between the pressure chamber and the lift pump.

12 . The method of claim 9 , further comprising during the engine stop, closing an inlet valve positioned between the lift pump and a single pressure chamber of the HPP for regulating fuel flow there-between to restrict fuel flow between the pressure chamber and the lift pump.

13 . The method of claim 9 , where the operating the HPP in the unpressurized mode comprises maintaining a volume control valve positioned between the lift pump and the HPP in a closed position during both intake and compression strokes of the HPP.

14 . The method of claim 9 , where the operating the HPP in the unpressurized mode comprises maintaining an inlet valve positioned between the lift pump and a single pressure chamber of the HPP in an open position to permit fuel flow between the pressure chamber and the lift pump and add pressure to fuel included upstream of the pressure chamber, between the pressure chamber and the lift pump.

15 . The method of claim 9 , wherein the switching the HPP to the pressurized mode comprises opening a volume control valve positioned between the lift pump and the HPP during both intake and compression strokes of the HPP.

16 . The method of claim 9 , wherein the switching the HPP to the pressurized mode comprises opening an inlet valve positioned between the lift pump and a single pressure chamber of the HPP during an intake stroke of a piston of the pressure chamber to supply fuel to the pressure chamber, and closing the inlet valve during a portion or all of a compression stroke of the piston of the pressure chamber to add pressure to fuel included downstream of the HPP, between the HPP and one or more fuel injectors.

17 . The method of claim 9 , wherein the powering on the lift pump occurs before initiating cylinder combustion, and wherein the method further comprises after powering on the lift pump, waiting a duration before initiating cylinder combustion.

18 . The method of claim 9 , wherein the powering on the lift pump and the initiating cylinder combustion occur approxima

Assignees

• Ford Global Tech Llc

Inventors

• Hermann Dietmar
• Reuter Uwe
• Van Bebber David

Classifications

• F02D41/26

  using computer, e.g. microprocessor · CPC title

• F02D41/3818

  for petrol engines · CPC title

• F02D41/3827

  for diesel engines · CPC title

• F02D41/3863 Primary

  by controlling the flow out of the common rail, e.g. using pressure relief valves · CPC title

• F02D41/062 Primary

  for starting (F02D41/061 takes precedence) · CPC title