GB2575275A - A method of determining the functionality of an NRV in a high pressure fuel pump system - Google Patents

A method of determining the functionality of an NRV in a high pressure fuel pump system Download PDF

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Publication number
GB2575275A
GB2575275A GB1810939.7A GB201810939A GB2575275A GB 2575275 A GB2575275 A GB 2575275A GB 201810939 A GB201810939 A GB 201810939A GB 2575275 A GB2575275 A GB 2575275A
Authority
GB
United Kingdom
Prior art keywords
nrv
determining
functionality
inlet valve
fuel
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB1810939.7A
Other versions
GB201810939D0 (en
Inventor
J Lane David
Male Andrew
Logue Samuel
O'connell Charlotte
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Delphi Technologies IP Ltd
Original Assignee
Delphi Technologies IP Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Delphi Technologies IP Ltd filed Critical Delphi Technologies IP Ltd
Priority to GB1810939.7A priority Critical patent/GB2575275A/en
Publication of GB201810939D0 publication Critical patent/GB201810939D0/en
Publication of GB2575275A publication Critical patent/GB2575275A/en
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/22—Safety or indicating devices for abnormal conditions
    • F02D41/221—Safety or indicating devices for abnormal conditions relating to the failure of actuators or electrically driven elements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D1/00—Controlling fuel-injection pumps, e.g. of high pressure injection type
    • F02D1/02—Controlling fuel-injection pumps, e.g. of high pressure injection type not restricted to adjustment of injection timing, e.g. varying amount of fuel delivered
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/30—Controlling fuel injection
    • F02D41/38—Controlling fuel injection of the high pressure type
    • F02D41/3809—Common rail control systems
    • F02D41/3836—Controlling the fuel pressure
    • F02D41/3845—Controlling the fuel pressure by controlling the flow into the common rail, e.g. the amount of fuel pumped
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/30—Controlling fuel injection
    • F02D41/38—Controlling fuel injection of the high pressure type
    • F02D41/40—Controlling fuel injection of the high pressure type with means for controlling injection timing or duration
    • F02D41/406—Electrically controlling a diesel injection pump
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D1/00—Controlling fuel-injection pumps, e.g. of high pressure injection type
    • F02D1/02—Controlling fuel-injection pumps, e.g. of high pressure injection type not restricted to adjustment of injection timing, e.g. varying amount of fuel delivered
    • F02D1/08—Transmission of control impulse to pump control, e.g. with power drive or power assistance
    • F02D2001/082—Transmission of control impulse to pump control, e.g. with power drive or power assistance electric
    • F02D2001/085—Transmission of control impulse to pump control, e.g. with power drive or power assistance electric using solenoids
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/20—Output circuits, e.g. for controlling currents in command coils
    • F02D2041/202—Output circuits, e.g. for controlling currents in command coils characterised by the control of the circuit
    • F02D2041/2055—Output circuits, e.g. for controlling currents in command coils characterised by the control of the circuit with means for determining actual opening or closing time
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/22—Safety or indicating devices for abnormal conditions
    • F02D2041/224—Diagnosis of the fuel system
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2250/00—Engine control related to specific problems or objectives
    • F02D2250/14—Timing of measurement, e.g. synchronisation of measurements to the engine cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
    • F02M59/20—Varying fuel delivery in quantity or timing
    • F02M59/36—Varying fuel delivery in quantity or timing by variably-timed valves controlling fuel passages to pumping elements or overflow passages
    • F02M59/366—Valves being actuated electrically
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M65/00—Testing fuel-injection apparatus, e.g. testing injection timing ; Cleaning of fuel-injection apparatus
    • F02M65/006—Measuring or detecting fuel leakage of fuel injection apparatus

Abstract

A method of determining the functionality of a non-return valve (NRV) in a high pressure fuel pump comprising a cam driven plunger, an outlet with a NRV and a solenoid operated inlet valve is disclosed. The method comprises measuring the voltage signal across the solenoid and cam angle; analysing the signal to determine the start of inlet valve opening and the associated cam angle; and determining the functionality of the NRV based on this determination. The opening of the inlet valve, which may be an outlet metering valve (OMV), may be detected by a voltage pulse 12 substantially after the end of the solenoid activation pulse 9. The method may determine if the valve opening’s associate cam angle changes with time which may be used to determine functionality such as wear leakage. The method overcomes manufacturing error or wear during operation, that may reduce the sealing effectiveness of the NRV, that result in incorrect control of the pump and inefficiencies.

Description

TECHNICAL FIELD
This disclosure relates to high pressure fuel pump systems. It has particular application to such systems which include an Outlet Metering Valve (OMV) or an Inlet valve which is solenoid controlled .
BACKGROUND OF THE INVENTION
Typically, high pressure fuel pumps comprise a cam driven plunger pump adapted to pressurize fuel in a pressurization chamber. There is provided an inlet to the pump, via an inlet valve, to the pressurization chamber, as well as an outlet. Downstream of the outlet is typically provided a non-retum valve (NRV). Pressurized fuel from the pump is provided to a common rail or accumulator volume, and supplied further to one or more fuel injectors. The inlet valve may be solenoid controlled.
In certain arrangements an Outlet Metering Valve (OMV) is provided, which is arranged to receive fuel from the fuel supply and well as having an inlet from the outlet side of the fuel pump. The OMV provides fuel to the pressurization chamber of the pump. Thus appropriate control of the OMV can provide a flow of fuel from the high pressure side back to the inlet. The OMV is typically a solenoid operated fuel valve, controlled so as to controllably allow fuel to flow back to the inlet path. So in such pumping systems, the OMV has a drive current/voltage applied to the solenoid in order to actuate it.
Aspects of the invention are applicable to arrangements where there is such an OMV connected to the high pressure output or where there is an solenoid controlled inlet valve and no such connection.
A problem with such pumping systems is that due to manufacturing errors or wear during operation, the sealing effectiveness of the NRV can be reduced, which can result in incorrect control of the whole pumping system and inefficiencies.
It is an object of the invention to overcome this problem.
SUMMARY OF THE INVENTION
In one aspect is provided, in a high pressure fuel pump system comprising a high pressure fuel pump, said pump comprising a cam driven plunger, adapted to pressurise fuel in a pressurization chamber, said chamber including an inlet and high pressure fuel outlet, said system including a non-return valve (NRV) located downstream of said outlet, and a solenoid operated inlet valve adapted to control flow of fuel into said chamber via said inlet, a method of determining the functionality of said NRV, comprising
a) obtaining a signal of the voltage across said solenoid of said solenoid operated inlet valve valve against cam angle;
b) analysing said signal to detect the start of the inlet valve opening with cam angle;
c) determining the functionality of said NRV from the results of step b).
Step b) may comprise detecting a pulse in the voltage signal substantially after the end of a solenoid activation pulse.
The method may comprise repeating the method steps to determine changes in start of inlet valve opening against cam angle with time.
Determining said functionality may be determining wear of said NRV, and wherein said wear is determined from said determined changes.
Determining said functionality may comprises determining the situation if any fuel is leaking away from the pumping chamber, increased plunger leakage or face separation, form said determined changes.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention is now described by way of example with reference to the accompanying drawings in which:
Figure 1 shows a schematic arrangement of a portion of a high pressure fuel system;
- Figure 2a and 2 b illustrate how the start of OMV/inlet valve opening point may be determined by analysing the voltage trace of the solenoid by the ECU.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Figure 1 shows a schematic arrangement of a portion of a high pressure fuel system. Here fuel is provided from a low pressure supply 1 to a high pressure pump (system) which comprises a cam driven plunger pump 2 adapted to pressurize fuel in a pressurization chamber 3. There is provided an inlet 8 to the pressurization chamber, as well as an outlet 4. Downstream of the outlet is typically provided a non-return valve (NRV) 5. Pressurised fuel from the pump is provided to a common rail or accumulator volume 6, and supplied further to one or more fuel injectors. The fuel rail typically includes a pressure sensor associated with it. An Outlet Metering Valve (OMV) 6 is provided, which is arranged as shown and is fluidly connected to the high pressure fuel supply to the common rail (downstream of the NRV) as well as the low pressure fuel supply. The OMV supplies fuel to the inlet of the pump.
The OMV may be a solenoid operated valve, and being connected to the pressurized fuel from the pump outlet, can be controlled (e.g. by the ECU) to allow controllable fuel flow back to the inlet. It can be regarded as an inlet valve but is referred commonly to as an Outlet Metering Valve due to the fact it controls the amount of fuel being metered out of the plunger chamber and past the NRV and into the common rail.
In one aspect of the invention the point at which a solenoid operated inlet valve or OMV is opened to allow fuel to enter the pressurization chamber in a cycle is determined from the voltage trace of the OMV/inlet valve solenoid, and this point is determined and may be analysed over time (with cam position). This may be used amongst other things, to determine valve wear / operation of the Non Return Valve. This can be in turn used to adapt the control to allow optimum efficiencies.
So in one example the opening point of the OMV / Inlet valve is determined by measuring the voltage signal across the solenoid using existing hardware (ECU and wire lead (harness)). The voltage across the solenoid may be recorded, and the signal analysed. This allows determination of the time point when the inlet valve / OMV begins to move (open) during the filling stroke. By knowing the point at which the OMV / inlet valve begins to open allows us to calculate certain fluid parameters and running conditions, but also as a method to detect defects in the manufacturing process or wear over life that lead to poor sealing performance.
Figure 2a and 2b illustrate how the start of OMV / inlet valve opening point may be determined by analysing the voltage trace of the solenoid by the ECU. Every pumping event must have a waveform applied to the solenoid, therefore every pumping event will have an inlet valve opening point (assuming the valve has latched). After Top Dead Centre (TDC), although there is no direct waveform being applied to the OMV / inlet valve solenoid, the inlet valve armature moving from the full lift position towards the lift stop creates a change in flux path which provides a minute blip in the voltage trace (as illustrated below). The detection of this ‘blip’ can be automated, allowing for the constant analysis of OMV / inlet valve opening position.
Figure 2a shows plot 10 against time / cam profile of the voltage across the OMV. In the following the same is applicable to an inlet valve which is solenoid controlled. The voltage trace shows that the voltage across the OMV solenoid increases as initially voltage is applied to actuate the OMV, during an activation period 9 and then falls to zero. The time point (with reference to the cam angle) at which the OMV starts to open is at Ts, in the region A at blip 12. Figure 2b shows a detailed view of region A; i.e. the region of the valve opening. As can be seen there is a small blip or glitch 12 in the voltage signal when the valve opens. By detecting this the valve opening time can be determined. The cam profile is shown by reference numeral 13. Measurement may be over a defined time (cam angle) interval; from tl to t2.
By knowing the point at which the valve begins to open (e.g. against cam position) we can define certain fuel properties such as the bulk modulus, as valve opening position is a function of pressure / volume / fuel properties whereby pressure and volumes are known.
Also, by being able to detect the point at which the OMV / inlet valve opens (e.g. against cam position) we can determine the quality of the NRV sealing. In order for the OMV / inlet valve to open following a pumping event, the pressure in the plunger chamber (below the Non-Retum Valve (NRV)) must drop. This is done by expanding the volume of the chamber by lowering the plunger. If the NRV sealing performance is within design specifications, the point at which the OMV / inlet valve opens should be constant for a given rail pressure. In circumstances where the sealing performance of the NRV is not within tolerance, the high pressure fuel from the rail acting above the NRV will leak back into the plunger chamber. This decreases the rate of pressure drop within the plunger chamber, meaning an increased proportion of the stroke must be used to expand the fuel enough for pressure to drop, allowing the valve to open. Thus the point in terms of cam position on opening (detected by the pulse) becomes later.
By checking for inconsistencies in the OMV / inlet valve opening point against cam position, or if it’s consistently later than a predetermined threshold in the pump cycle 1, the NRV sealing performance can be assumed to be poor and hence would not pass the check.
Similarly, an early detection of the OMV / inlet valve opening event would illustrate that high pressure fuel is leaking away from the pumping chamber at a higher rate than the design specification. This could be due to increased plunger leakage / face separation etc and could also be used as a fail-safe method to catch 5 poor assemblies during manufacturing or detect wear during operation. In other words, this method can be used to check for high internal leakage from a source such as a plunger or high pressure interface.

Claims (5)

1. In a high pressure fuel pump system comprising a high pressure fuel pump, said pump comprising a cam driven plunger, adapted to pressurise fuel in a pressurization chamber, said chamber including an inlet and high pressure fuel outlet, said system including a non-return valve (NRV) located downstream of said outlet, and a solenoid operated inlet valve adapted to control flow of fuel into said chamber via said inlet, a method of determining the functionality of said NRV, comprising
a) obtaining a signal of the voltage across said solenoid of said solenoid operated inlet valve valve against cam angle;
b) analysing said signal to detect the start of the inlet valve opening with cam angle;
c) determining the functionality of said NRV from the results of step b).
2. A method as claimed where step b) comprises detecting a pulse in the voltage signal substantially after the end of a solenoid activation pulse.
3. A method as claimed in claims 1 to 2 comprising repeating the method steps to determine changes in start of inlet valve opening against cam angle with time.
4. A method as claimed in claim 3 where said determining said functionality is the of determining wear of said NRV, and wherein said wear is determined from said determined changes.
5. A method as claimed in claims 1 to 4 wherein said determining said functionality comprises determining the situation if any fuel is leaking away from the pumping chamber, increased plunger leakage or face separation, form said determined changes.
GB1810939.7A 2018-07-04 2018-07-04 A method of determining the functionality of an NRV in a high pressure fuel pump system Withdrawn GB2575275A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB1810939.7A GB2575275A (en) 2018-07-04 2018-07-04 A method of determining the functionality of an NRV in a high pressure fuel pump system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1810939.7A GB2575275A (en) 2018-07-04 2018-07-04 A method of determining the functionality of an NRV in a high pressure fuel pump system

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GB201810939D0 GB201810939D0 (en) 2018-08-15
GB2575275A true GB2575275A (en) 2020-01-08

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2112469A (en) * 1981-12-09 1983-07-20 Bosch Gmbh Robert A fuel injection pump having a device for producing a fuel quantity signal
DE102010030447A1 (en) * 2010-06-23 2011-12-29 Bayerische Motoren Werke Aktiengesellschaft Method for determining position of top dead point in HDP5 in combustion engine for direct injection of petrol, involves determining opening point by measuring electrical variable in electrical current supply path for solenoid coil
WO2018109359A1 (en) * 2016-12-15 2018-06-21 Continental Automotive France Method for estimating a top dead centre for a high-pressure pump of a fuel injection system in an automotive vehicle engine

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2112469A (en) * 1981-12-09 1983-07-20 Bosch Gmbh Robert A fuel injection pump having a device for producing a fuel quantity signal
DE102010030447A1 (en) * 2010-06-23 2011-12-29 Bayerische Motoren Werke Aktiengesellschaft Method for determining position of top dead point in HDP5 in combustion engine for direct injection of petrol, involves determining opening point by measuring electrical variable in electrical current supply path for solenoid coil
WO2018109359A1 (en) * 2016-12-15 2018-06-21 Continental Automotive France Method for estimating a top dead centre for a high-pressure pump of a fuel injection system in an automotive vehicle engine

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Publication number Publication date
GB201810939D0 (en) 2018-08-15

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