METHOD FOR OPERATING AN INTERNAL COMBUSTION ENGINE, INJECTION SYSTEM FOR AN INTERNAL COMBUSTION ENGINE AND INTERNAL COMBUSTION ENGINE

• US 20170067409A1
• Filed: 06/26/2015
• Published: 03/09/2017
• Est. Priority Date: 07/14/2014
• Status: Active Grant

• Current Assignee: Rolls-Royce Solutions GmbH (Rolls-Royce Holdings Plc)
• Original Assignee: MTU Friedrichshafen GmbH (Rolls-Royce Holdings Plc)
• Inventors: DLKER, Armin
• Granted Patent: US 10,787,987 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F02D 2041/1418 Several control loops, either as alternatives or simultaneous
• CPC Class Codes: F02D 2041/223 Diagnosis of fuel pressure sensors
• CPC Class Codes: F02D 2041/226 Fail safe control for fuel injection pump
• CPC Class Codes: F02D 2200/0802 Temperature of the exhaust gas treatment apparatus
• CPC Class Codes: F02D 41/22 Safety or indicating devices for abnormal conditions in air/fuel ratio feedback systems F02D41/1495, in electric control linkage F02D11/107, in purge control systems F02M25/0809
• CPC Class Codes: F02D 41/3845 by controlling the flow into the common rail, e.g. the amount of fuel pumped
• CPC Class Codes: F02D 41/3863 by controlling the flow out of the common rail, e.g. using pressure relief valves
• CPC Class Codes: F02M 2200/40 Fuel-injection apparatus with fuel accumulators, e.g. a fuel injector having an integrated fuel accumulator
• CPC Class Codes: F02M 59/46 Valves
• CPC Class Codes: F02M 63/0225 Fuel-injection apparatus having a common rail feeding several injectors F02M63/0003 takes precedence; Means for varying pressure in common rails; Pumps feeding common rails
• CPC Class Codes: F02M 63/023 Means for varying pressure in common rails pressure control F02D41/3845
• CPC Class Codes: F02M 63/025 from the common rail

Abstract

A method for operating an internal combustion engine having an injection system which has a high-pressure accumulator, wherein a high pressure in the high-pressure accumulator is regulated via a suction throttle on the low-pressure side as a first pressure control member in a first high-pressure control loop, wherein in a normal operation a high-pressure disturbance variable is produced via a pressure control valve on the high-pressure side as a second pressure control member, via which fuel is redirected from the high-pressure accumulator to a fuel reservoir. For this purpose, the high pressure in a safety operation is regulated by the pressure control valve via a second high pressure control loop, or, in the safety operation, a maximum fuel volume flow is continuously redirected from the high pressure accumulator to the fuel reservoir via the pressure control valve.

Claims

1-10. -10. (canceled)

11. A method for operating an internal combustion engine having an injection system with a high-pressure accumulator, the method comprising the steps of:

regulating a high pressure in the high-pressure accumulator using a low-pressure-side suction throttle as a first pressure setting element a first high-pressure regulating loop;

generating, in a normal operating mode, a high-pressure disturbance variable using of a high-pressure-side pressure regulating valve as a second pressure setting element by way of which fuel is discharged from the high-pressure accumulator into a fuel reservoir; and

, in a protective operating mode, regulating the high pressure using the pressure regulating valve by way of a second high-pressure regulating loop, or permanently opening the pressure regulating valve in the protective operating mode.

12. The method according to claim 11, including setting a first operation type of the protective operating mode if the high pressure reaches or overshoots a first pressure threshold value, wherein, in the first operation type, the pressure regulating valve performs the regulation of the high pressure.

13. The method according to claim 12, including setting a second operation type of the protective operating mode if the high pressure overshoots a second pressure threshold value or if a defect of a high-pressure sensor is detected, wherein, in the second operation type, the pressure regulating valve is permanently opened.

15. The method according to claim 12, including permanently opening the suction throttle in the second operation type and/or in the first operation type of the protective operating mode.

16. An injection system for an internal combustion engine, comprising:

a high-pressure pump;

at least one injector;

a high-pressure accumulator that is fluidically connected at one side to the at least one injector and at another side via the high-pressure pump to a fuel reservoir;

a suction throttle assigned to the high-pressure pump as the first pressure setting element;

a pressure regulating valve that fluidically connects the high-pressure accumulator to the fuel reservoir; and

a control unit operatively connected to the at least one injector, to the suction throttle and to the pressure regulating valve, wherein the control unit is operative to carry out a method according to claim 11.

17. The injection system according to claim 16, wherein the pressure regulating valve is open when deenergized.

18. The injection system according to claim 16, wherein the pressure regulating valve is closed when unpressurized and deenergized, wherein said pressure regulating valve is closed when subjected to a pressure up to an opening pressure value prevailing on an inlet side, wherein said pressure regulating valve opens when the pressure prevailing on an inlet side reaches or overshoots the opening pressure value in a deenergized state.

19. The injection system according to claim 16, wherein the injection system has no mechanical pressure relief valve.