GB2544740A - Method to determine characteristics of a valve in a fuel system - Google Patents

Method to determine characteristics of a valve in a fuel system Download PDF

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Publication number
GB2544740A
GB2544740A GB1520688.1A GB201520688A GB2544740A GB 2544740 A GB2544740 A GB 2544740A GB 201520688 A GB201520688 A GB 201520688A GB 2544740 A GB2544740 A GB 2544740A
Authority
GB
United Kingdom
Prior art keywords
pressure
valve
pump
low pressure
opening
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Withdrawn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
GB1520688.1A
Other versions
GB201520688D0 (en
Inventor
Voigt Peter
Hennig Christian
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 International Operations Luxembourg SARL
Original Assignee
Delphi International Operations Luxembourg SARL
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 International Operations Luxembourg SARL filed Critical Delphi International Operations Luxembourg SARL
Priority to GB1520688.1A priority Critical patent/GB2544740A/en
Publication of GB201520688D0 publication Critical patent/GB201520688D0/en
Publication of GB2544740A publication Critical patent/GB2544740A/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Withdrawn legal-status Critical Current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
    • F02D41/24—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means
    • F02D41/2406—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means using essentially read only memories
    • F02D41/2425—Particular ways of programming the data
    • F02D41/2429—Methods of calibrating or learning
    • F02D41/2438—Active learning methods
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D33/00—Controlling delivery of fuel or combustion-air, not otherwise provided for
    • 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
    • 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
    • F02D41/3082—Control of electrical fuel pumps
    • 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
    • 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
    • F02M59/44—Details, components parts, or accessories not provided for in, or of interest apart from, the apparatus of groups F02M59/02 - F02M59/42; Pumps having transducers, e.g. to measure displacement of pump rack or piston
    • 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
    • F02M59/44—Details, components parts, or accessories not provided for in, or of interest apart from, the apparatus of groups F02M59/02 - F02M59/42; Pumps having transducers, e.g. to measure displacement of pump rack or piston
    • F02M59/46—Valves
    • 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
    • F02D2041/2058—Output circuits, e.g. for controlling currents in command coils characterised by the control of the circuit using information of the actual current value
    • 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
    • F02D41/222—Safety or indicating devices for abnormal conditions relating to the failure of sensors or parameter detection devices
    • F02D2041/223—Diagnosis of fuel pressure sensors
    • 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
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/24—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means
    • F02D41/2406—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means using essentially read only memories
    • F02D41/2425—Particular ways of programming the data
    • F02D41/2429—Methods of calibrating or learning
    • F02D41/2451—Methods of calibrating or learning characterised by what is learned or calibrated

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fuel-Injection Apparatus (AREA)

Abstract

Disclosed is a method of determining the opening characteristics of a pressure limiting valve in a fuel delivery system. The fuel delivery system comprises an electrical low pressure pump 3 fluidly connected via a low pressure circuit 7 to a high pressure pump 5. The high pressure pump 5 is connected in parallel with a pressure limiting valve 6 and is adapted to provide fuel to a high pressure circuit. The pressure limiting valve 6 is adapted to open to allow fuel to flow from the low pressure circuit 7 to the high pressure circuit when an opening pressure of the pressure limiting valve is achieved. The method comprises the steps of activating the low pressure pump, measuring one or more characteristics of electrical drive parameters of the low pressure pump, detecting the point at which there is a step change in the gradient of an electrical drive parameter, recording electrical drive parameters at the detected point and using the recorded parameters at the detected point to determine the opening characteristics of the valve. The method can be used to determine the opening point and/or opening pressure of a pressure limiting valve based on sensing the current, voltage or power of an electrical drive of a fuel pump without the use of a pressure sensor.

Description

Method to Determine Characteristics Of a Valve in a Fuel System Field of the Invention
This disclosure relates to systems adapted to provide fuel at high pressure and has particular but non exclusive application to systems designed to provide fuel at high pressure to fuel injectors of internal combustion engines.
Background
Systems designed to deliver fuel under high pressure to fuel injectors typically incorporate flow circuitry including a low pressure pump (such as an electronic lift pump) fluidly connected to a fuel tank to provide fuel under low pressure to a high pressure pump such as a piston or plunger type pump. The high pressure pump then delivers fuel under high pressure to a number of fuel injectors.
High pressure pumps such as a single piston (e.g. Diesel high pressure) pump creates large pressure spikes in the low pressure circuit. (It is to be noted that there is often a backleak circuit from a high pressure circuit to the low pressure circuit.)These can lead to failure of the low pressure circuit/system such as fuel leaks, and cause vibration. To reduce these pulsations, a pressure limiting valve is typically provided and is often integrated with the high pressure pump. The flow through such a valve is valve is strongly dependent on the opening pressure required to open the valve. With current designs, the tolerance of the opening pressure is a function of various design parameter tolerances. This consequently means the manufacture of valve components needs to be very need to be very precise with small tolerances. A further consequence of this is high manufacturing cost and high rejection rates in the production. A further problem is that the characteristics of the valve may vary over the lifetime of the valve due to wear and tear, and thus the pressure at which the valve opens (opening pressure) will vary.
Current strategies focus on direct pressure measurement using a pressure sensor to obtain data pertaining to the opening pressure of the valve. This however adds expense.
It is an object of the invention to overcome these problems.
Statement of the Invention
In one aspect of the invention is provided, in a fuel delivery system, said system including an electrical low pressure pump fluidly connected via a low pressure circuit to a high pressure pump, said high pressure pump being connected in parallel with a pressure limiting valve, and adapted to provide fuel to a high pressure circuit, and wherein said pressure limiting valve is adapted to open to allow fuel to flow from said low pressure circuit to said high pressure circuit, when the opening pressure of said pressure limiting valve is achieved, a method of determining the opening characteristics of the said valve comprising; i) activating the low pressure pump; ii) measuring one or more characteristics of the electrical drive parameters of the low pressure pump; iii) detecting the point at which there is a step change in the gradient of one or more of said characteristics of step ii), and recording electrical drive parameters at said detected point, iv) using said recorded parameters at said detected point to determine said opening characteristics of said valve.
The said electrical drive characteristics may include one or more of the following , drive current, drive voltage or drive power.
Step iv) may comprise determining when said valve opens.
The method may include determining the valve opening pressure from said recorded parameters at said detected point, and pre-stored data relating the valve opening pressure to the electrical drive parameters at which said step change occurs.
Brief Description of Drawings
The invention will now be described with reference to the following figures of which:
Figure 1 shows a basic fuel circuit used to supply for example fuel at high pressure from the tank to a number of fuel injectors/fuel injection equipment;
Figure 2a shows the effective hydraulic resistance of the unit comprising the high pressure pump and pressure limiting valve connected in parallel, and how this varies consequent to activation of the pump;
Figure 2 b shows the equivalent drive current for the low pressure pump over the same time period.
Detailed Description of the Invention
Figure 1 shows a basic fuel circuit used to supply for example fuel at high pressure from the tank to a number of fuel injectors/fuel injection equipment. The circuit is simplified and real life circuits may include further filters, pressure regulators, backleak paths, and such like.
In essence a low pressure electrical pump 3 such as an electronic lift pump is used to pump fuel from a tank 1 via low pressure circuit 7 which includes a filter 4, to a high pressure pump 5 such as a piston pump. Typically to avoid pressure pulsation (pressure spikes) in the low pressure circuitry 7 (e.g. from the high pressure or indeed low pressure pump) a low pressure limiting valve 6 may be included and arranged in parallel with the high pressure pump 6 (as mentioned this may be provided integral with the pump). This valve is arranged (set) to open when the pressure in the low pressure circuits exceeds a certain level, equivalent to valve opening pressure.
Variation of the characteristics of individual valves, e.g. caused by manufacturing variation, means that the level of pressure required to open the pump may vary. A further problem is that the characteristics of the valve may vary over the lifetime of the valve due to wear and tear.
It is one object of the invention to provide an estimate in the characteristics of the valve and how these change over time, and in particular to provide an estimation of the point at which the valve opens, and how this may change over time, and in particular the valve opening pressure.
Figure 2a shows the effective hydraulic resistance of the unit comprising the high pressure pump and pressure limiting valve connected in parallel, and how this varies consequent to activation of the pump. After pump is activated there is a drop in hydraulic resistance, characterized here by a step change in the gradient of hydraulic resistance over time. Thus it has been determined than at the opening point of the valve, the hydraulic resistance of the pump/valve arrangement drops; as shown there is a quantum drop in the rate of change of the effective hydraulic resistance.
Figure 2 b shows the equivalent drive current through the electrical low pressure pump over the same time period. The current through the drive circuit of the low pressure pump (e.g. lift pump) increases at a generally constant rate until the valve open, which as a consequence of the step decrease in hydraulic resistance rate, causing a corresponding (e.g. step) decrease in the drive current rate. Thus this “glitch” point (change in gradient) as shown by the arrows, determines the point P at which the valve opens.
Aspect of the invention make use of this. During operation characteristics of the drive circuitry such as drive current or voltage or power across the electrical low pressure pump are measured and the glitch point identified. The time and/or current/voltage/power at the glitch point may be recorded and compared with previously determined or pre-stored values to give information in the characteristics of the valve, or changes thereof.
Preferably the glitch point in terms of voltage or current or power across the low pressure pump is previously mapped to the valve opening pressure. Such a map may be stored in an engine ECU. Thus during operation the determined glitch point (e g. in terms of electrical characteristics such as current/power/voltage) is used to determine from an ECU map or look-up table, the current valve opening pressure.
Thus in refined aspect of the invention the current/voltage/power or time at which the glitch occurs may be mapped to the pressure values required to open the low pressure limiting valve (valve opening pressure).
The thus determined valve opening pressure can be used in various engine control aspects and methodologies.
So to summarise aspects of the invention, the high pressure pump and pressure limiting valve arrangement can be considered as a hydraulic resistor, the resistance significantly changes once the LPL valves opens. The low pressure electrical pump (electrical lift pump ELP) located e.g. in the tank is driven with a current. As soon as the LPL valve opens, the hydraulic resistance drops rapidly, leading to a glitch in the low pressure (e.g. EPL) pump valve current curve, such a a step change in gradient, which can be detected and recorded e.g. by the ECU. The thus detected low pressure (ELP) current/voltage data at which the glitch occurs can be used to detect valve opening point, and also determine changes in, or absolute values of, the valve opening pressure. The latter can be performed by providing a map (e.g. stored in an engine ECU) which correlates opening pressure for the LPL valve with electrical characteristics of the low pressure pump drive (current/voltage/power) at the glitch point.

Claims (4)

Claims
1. In a fuel delivery system, said system including an electrical low pressure pump fluidly connected via a low pressure circuit to a high pressure pump, said high pressure pump being connected in parallel with a pressure limiting valve, and adapted to provide fuel to a high pressure circuit, and wherein said pressure limiting valve is adapted to open to allow fuel to flow from said low pressure circuit to said high pressure circuit, when the opening pressure of said pressure limiting valve is achieved, a method of determining the opening characteristics of the said valve comprising; i) activating the low pressure pump; ii) measuring one or more characteristics of the electrical drive parameters of the low pressure pump; iii) detecting the point at which there is a step change in the gradient of one or more of said characteristics of step ii), and recording electrical drive parameters at said detected point, iv) using said recorded parameters at said detected point to determine said opening characteristics of said valve.
2. A method as claimed in claim 1 where said electrical drive characteristics include one or more of the following , drive current, drive voltage or drive power.
3. A method as claimed in claim 1 or 2 wherein step iv) comprises determining when said valve opens.
4. A method as claimed in claims 1 or 2 including determining the valve opening pressure from said recorded parameters at said detected point, and pre-stored data relating the valve opening pressure to the electrical drive parameters at which said step change occurs.
GB1520688.1A 2015-11-24 2015-11-24 Method to determine characteristics of a valve in a fuel system Withdrawn GB2544740A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB1520688.1A GB2544740A (en) 2015-11-24 2015-11-24 Method to determine characteristics of a valve in a fuel system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1520688.1A GB2544740A (en) 2015-11-24 2015-11-24 Method to determine characteristics of a valve in a fuel system

Publications (2)

Publication Number Publication Date
GB201520688D0 GB201520688D0 (en) 2016-01-06
GB2544740A true GB2544740A (en) 2017-05-31

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Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10189466B2 (en) * 2016-11-30 2019-01-29 Ford Global Technologies, Llc Identifying in-range fuel pressure sensor error

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20120156057A1 (en) * 2010-12-17 2012-06-21 Aisan Kogyo Kabushiki Kaisha Fuel supply apparatus
US20150275812A1 (en) * 2012-10-15 2015-10-01 Denso Corporation Fuel supply device

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20120156057A1 (en) * 2010-12-17 2012-06-21 Aisan Kogyo Kabushiki Kaisha Fuel supply apparatus
US20150275812A1 (en) * 2012-10-15 2015-10-01 Denso Corporation Fuel supply device

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Free format text: REGISTERED BETWEEN 20190222 AND 20190227

WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)