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GB2568090A - Method for determining the bulk modulus of a fuel - Google Patents

Method for determining the bulk modulus of a fuel Download PDF

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Publication number
GB2568090A
GB2568090A GB1718312.0A GB201718312A GB2568090A GB 2568090 A GB2568090 A GB 2568090A GB 201718312 A GB201718312 A GB 201718312A GB 2568090 A GB2568090 A GB 2568090A
Authority
GB
United Kingdom
Prior art keywords
pump
fuel
determining
pressure
pumping chamber
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Withdrawn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
GB1718312.0A
Other versions
GB201718312D0 (en
Inventor
Male Andrew
J Lane David
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.)
Borgwarner US Technologies LLC
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 GB1718312.0A priority Critical patent/GB2568090A/en
Publication of GB201718312D0 publication Critical patent/GB201718312D0/en
Priority to PCT/EP2018/080148 priority patent/WO2019086659A1/en
Publication of GB2568090A publication Critical patent/GB2568090A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02DCONTROLLING COMBUSTION ENGINES
    • F02D41/00Electrical control of supply of combustible mixture or its constituents
    • F02D41/30Controlling fuel injection
    • F02D41/38Controlling fuel injection of the high pressure type
    • F02D41/3809Common rail control systems
    • F02D41/3836Controlling the fuel pressure
    • F02D41/3845Controlling the fuel pressure by controlling the flow into the common rail, e.g. the amount of fuel pumped
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/22Fuels; Explosives
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02DCONTROLLING COMBUSTION ENGINES
    • F02D41/00Electrical control of supply of combustible mixture or its constituents
    • F02D41/20Output circuits, e.g. for controlling currents in command coils
    • F02D2041/202Output circuits, e.g. for controlling currents in command coils characterised by the control of the circuit
    • F02D2041/2055Output 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
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02DCONTROLLING COMBUSTION ENGINES
    • F02D41/00Electrical control of supply of combustible mixture or its constituents
    • F02D41/20Output circuits, e.g. for controlling currents in command coils
    • F02D2041/202Output circuits, e.g. for controlling currents in command coils characterised by the control of the circuit
    • F02D2041/2058Output circuits, e.g. for controlling currents in command coils characterised by the control of the circuit using information of the actual current value
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02DCONTROLLING COMBUSTION ENGINES
    • F02D2200/00Input parameters for engine control
    • F02D2200/02Input parameters for engine control the parameters being related to the engine
    • F02D2200/06Fuel or fuel supply system parameters
    • F02D2200/0611Fuel type, fuel composition or fuel quality
    • F02D2200/0612Fuel type, fuel composition or fuel quality determined by estimation
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02DCONTROLLING COMBUSTION ENGINES
    • F02D2250/00Engine control related to specific problems or objectives
    • F02D2250/14Timing of measurement, e.g. synchronisation of measurements to the engine cycle

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Biochemistry (AREA)
  • Medicinal Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Analytical Chemistry (AREA)
  • Food Science & Technology (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fuel-Injection Apparatus (AREA)

Abstract

A method of determining the bulk modulus of a fuel in a high pressure fuel pump system, said system including a high pressure fuel pump comprising a cam driven piston adapted to reciprocate within a pumping chamber so as to pressurize fuel therein, an inlet valve located upstream of an inlet to said chamber adapted to be actuated so as to open the valve to allow fuel to pass into said chamber comprising of, during an expansion stroke, the following steps;  a) determining the time point of the Top Dead Centre (TDC) of the piston; b) determining the time of inlet valve opening; c) determining the pumping chamber volume change between the time points determined at steps a) and b); d) determining the bulk modulus from the results of step c), the pump chamber dead volume and the outlet pressure of the pump and the inlet pressure of the pump.

Description

METHOD FOR DETERMINING THE BULK MODULUS OF A FUEL
TECHNICAL FIELD
The invention relates to a method for determining the bulk modulus of fuel in a high pressure fuel pump. The invention has particular application to fuel pumps which include a plunger type arrangement adapted to pressurize fuel in a pumping chamber, and where fuel may be output to fuel injectors via e.g. a common rail system.
BACKGROUND OF THE INVENTION
Fuel flow into a pressurizing chamber of a piston type pump is typically controlled by an inlet metering valve (IMV). The fuel is subsequently pressurized by such a plunger or piston, (typically cam driven) before the pressurized fuel is outlet, e.g. via a common rail, to fuel injection equipment. The outlet of fuel from the chamber may take place under control of an Outlet Metering Valve (OMV).
Currently fuel quality varies because of varying degrees of biodiesel content used globally. This means that the properties of the fuel can be variable, in particular bulk modulus (the fluid compressibility) can vary significantly. The variable fuel quality leads to increased failure of fuel systems (wear and deposits)
In certain cases methods for compensating for fuel quality or controlling engine parameters need to have an accurate determination of bulk modulus.
It is useful to know the bulk modulus of the fuel being used in the fuel system at any given time. This can be used to calculate inlet valve closing timing of a high pressure pump, so as to compensate for drift in performance. Also the data can be used to detect if non approved fuels are being used.
It is an object of the invention to provide a method of determining bulk modulus of fuel within a high pressure pumping system with minimum hardware.
SUMMARY OF THE INVENTION
In one aspect is provided a method of determining the bulk modulus of a fuel in a high pressure fuel pump system, said system including a high pressure fuel pump comprising a cam driven piston adapted to reciprocate within a pumping chamber so as to pressurize fuel therein, an inlet valve located upstream of an inlet to said chamber adapted to be actuated so as to open the valve to allow fuel to pass into said chamber comprising of, during an expansion stroke, the following steps;
a) determining the time point of the Top Dead Centre (TDC) of the piston;
b) determining the time of inlet valve opening;
c) determining the pumping chamber volume change between the time points determined at steps a) and b);
d) determining the bulk modulus from the results of step c), the pump chamber dead volume and the outlet pressure of the pump and the inlet pressure of the pump.
The bulk modulus (K) may be determined form the following equation:
K= - Vpcdv (Vpcvc/(Po-Pi) ) where,
Vpcdv is the pumping chamber dead volume; Vpcvc is pumping chamber volume determined from step c); Po is the pump outlet pressure, and Pi is the pump inlet pressure.
The inlet pressure Pi may be assumed to be zero.
The inlet valve may be a solenoid actuator valve, and step b) may comprise monitoring the current or voltage through across the solenoid coil and detecting a signal glitch indicative of valve opening.
Step b) may comprise detecting a pulse on an accelerometer signal, the accelerometer located on or adjacent to the inlet valve or pump, said pulse indicative of the inlet valve opening
Step c) the pumping chamber volume change may be determined from the cam speed, cam profile, pumping chamber dimensions and the time points determined in steps a) and b).
The pump system may include a common rail connected to the outlet of the pumping chamber, said common rail including a pressure sensor and where the outlet pressure determined in step is measured form said pressure sensor.
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 plot of pressure against volume during a pumping cycle with respect to the pumping chamber, as well as the corresponding cam angle and piston lift;
- Figures 2 and 3 show the voltage/current signal in a solenoid actuator of an inlet valve against (plunger position) cam angle at two pump speeds
- Figure 4 shows a flowchart of the methodology in an example of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Most high pressure fuel pumps in modern engines are provided by a piston /plunger arrangement, where the plunger is adapted to reciprocate so as to pressurize fuel in a pumping chamber. The plunger is typically driven by a cam. An inlet valve upstream of the pumping chamber controls the flow of fuel into the pumping chamber via a respective inlet valve and an outlet valve (typically a nonreturn valve) downstream of the pumping chamber, which is adapted to regulate the flow of pressurize fuel from an outlet of the pumping chamber. Fuel is subsequently delivered to e.g. an accumulator volume such as a common rail for delivery to fuel injectors.
Figure 1 upper plot shows a plot 1 of pressure against volume during a pumping cycle with respect to the pumping chamber. This PV diagram/plot shows a full pumping cycle; D to A shows the filling stroke where the plunger moves down as a result of cam movement to draw fuel into the pumping chamber, process A to B is the pressurization stroke (compression stroke), where the piston move upwards to compress fuel, process B to C is the delivery stroke where pressurized fuel is exited out the chamber via an outlet and process C to D is the expansion process at the end of the pumping stroke. The bottom plot 2 shows the corresponding plunger lift and cam angle. The Top Dead Centre (TDC) is shown by the vertical line on the left of the figure and marked as such.
The expansion process (C to D) is dependent on the fuel bulk modulus. During this time there is no fuel flow into the pressurization chamber as inlet valve is closed. Thus the fuel in the dead space is de-compressed (expanded) as the pressure is reduced consequent to the volume of the chamber increasing on the down stroke.
The lower the bulk modulus, the greater the change in volume in the drop of pressure from rail pressure to inlet pressure. In embodiments the inlet pressure is very small and may be assumed in examples to be zero.
The inlet valve is hydraulically unbalanced and cannot open until pressure in the pumping chamber has dropped to low levels (a few bar ~ supply pressure), this indicates the end of the expansion process. Therefore the lower the bulk modulus, the longer the timing (delay) for the valve to open after TDC and vice versa.
The inventors have made use of this realization to provide aspects of the invention. In figure the time between TDC and the inlet valve opening (the timing delay referred to above) is referred to as Tcd, that is the time between point C to point D.
Generally inlet valves such as inlet metering valves are electrically operated by a solenoid operated actuator. A glitch signal is the voltage waveform created in the solenoid coil when armature moves. This is due to residual magnetism in the solenoid components that provides a magnetic field, the motion of the armature distorts the magnetic field around the coil wires and this induces a voltage in the solenoid coil (Faraday’s Law). The ECU can potentially capture and analyse this waveform and determine timing. Glitches can be determined by looking at the trace of the voltage or current signal through or across the solenoid (actuator). The first or second derivative of this signal can be used to further identify the glitch. Such techniques or glitch identification are well known in the art.
The graphs of figures 2 and 3 below show the voltage/current signal 3inthe solenoid actuator of an inlet valve against (plunger position) cam angle at two pump speeds. In both cases there are low delivery rates of fuel hence the close proximity of the chopping voltage to TDC (90 degrees). The graphs show the timing of the glitches marked by the vertical lines 4. Vertical lines 5 and 6 mark the start and end of the selection window, for capturing the glitch.
The glitch thus can be used to determine the timing of the opening of the inlet valve after TDC.
Other methods comprise detecting a pulse on an accelerometer signal, the accelerometer located on or adjacent to the inlet valve or pump, said pulse indicative of the inlet valve opening
In basic methodology in one example , the glitch signal/ pulse time is used to determine the time point of the opening of the inlet valve; in other words by analyzing the timing of a glitch signal in the solenoid coil drive circuit caused by the opening of the inlet valve. Knowing the time point of TDC and the opening time of the inlet valve means the value of Ted, that is the expansion time, can be determined.
By knowing the expansion time, the speed of the cam, the cam profile and the chamber dimensions i.e. diameter of the chamber cylinder, the pumping chamber volume change, Vpcvc, during expansion (from point C to D) can be determined. So in other words the value of Vpcvc can be determined from the cam profile, chamber diameter and time of inlet valve opening, knowledge of when TDC is and cam speed. In other words the cam speed, time point of TDC and time point of inlet valve opening, allow the determination of the distance swept during expansion to be determined, and with chamber diameter, the chamber this swept volume can be determined.
The general formula for bulk modulus K is given
K = - V (dV/dp)
Applying this formula to the variable described above, V is the initial volume which is the pump chamber dead volume Vpcdv, known from the pump design geometry, dV is the pumping chamber volume change so Vpcvc, and dP is difference between outlet (rail) pressure and inlet pressure.
So the bulk modulus K can be determined by:
K= - Vpcdv (Vpcvc/(Po-Pi) ) where Po is the outlet pressure and Pi is the inlet pressure to the chamber.
In examples the outlet pressure Po can be assumed to be the rail pressure. The advantage of this is that pressure sensors are standardly fitted to common rails. Pi is very small and may be assumed to be zero.
So to recap the timing of the opening of the inlet valve is may in examples be dependent on following parameters: cam profile, rail pressure, pumping chamber dead volume and bulk modulus. Thus with a known cam profile, rail pressure and pumping chamber dead volume, the variation of timing of the opening of the inlet valve after TDC will be due to fuel bulk modulus alone.
So in an example method, rail pressure is measured (or pressure downstream of the pumping chamber i.e. pressure of pressurized fuel), the timing of the glitch signal of the inlet valve solenoid is determined, the cam speed determined and the TDC point determined and with the pump cylinder diameter, these variables used to determine the bulk modulus.
Figure 4 shows an example of the invention which is a flowchart of the methodology and timeline of calculation of fuel bulk modulus. In step SI after the plunger reaches TDC it moves down, as this process progresses the fuel in the chamber expands before the inlet valve is opened. This is equivalent to moving from point C to D in figure 1. The expansion takes place over time period Ted, that is the time between point C and point D.
In step S2 as a consequence the fuel in the chamber drops form rail pressure to substantially zero. In step S3 the inlet valve is opened by the solenoid actuator thereof; during. This time in step S4 the signal of the solenoid is monitored for the glitch to detect opening time. Alternatively a pulse on an accelerometer on the fuel pump is detected
In step S5 the with knowledge of the time of TDC of the plunger, and time of valve opening time form step S4, the expansion time Tcd can be determined. Using knowledge of the cam profile, cam speed and pumping chamber/cylinder dimensions e.g. diameter, the pumping chamber volume change during expansion (Ppcvc) can be calculated
Instep S6, Ppcvc along with pump dead volume (determined from design i.e. dimension data of the pump/pump chamber in step S7) is used with the measured rail pressure Po (from step S8) to determine the bulk modulus. Assuming zero pressure at the end of the expansion, the bulk modulus is determined from the following equation:
K= - Vpcdv (Vpcvc/Po)

Claims (7)

1. A method of determining the bulk modulus of a fuel in a high pressure fuel pump system, said system including a high pressure fuel pump comprising a cam driven piston adapted to reciprocate within a pumping chamber so as to pressurize fuel therein, an inlet valve located upstream of an inlet to said chamber adapted to be actuated so as to open the valve to allow fuel to pass into said chamber comprising of, during an expansion stroke, the following steps;
a) determining the time point of the Top Dead Centre (TDC) of the piston;
b) determining the time of inlet valve opening;
c) determining the pumping chamber volume change between the time points determined at steps a) and b);
d) determining the bulk modulus from the results of step c), the pump chamber dead volume and the outlet pressure of the pump and the inlet pressure of the pump.
2. A method as claimed in claim 1 where the bulk modulus K is determined form the following equation:
K= - Vpcdv (Vpcvc/(Po-Pi) ) where,
Vpcdv is the pumping chamber dead volume; Vpcvc is pumping chamber volume determined from step c); Po is the pump outlet pressure, and Pi is the pump inlet pressure.
3. A method as claimed in claims 1 or 2 where the inlet pressure Pi is assumed to be zero.
4. A method as claimed in claims 1 to 3 where said inlet valve is a solenoid actuator valve, and step b) comprises monitoring the current or voltage through across the solenoid coil and detecting a signal glitch indicative of valve opening.
5. A method as claimed in claims 1 to 3 where step b) comprising detecting a pulse on an accelerometer signal, the accelerometer located on or adjacent to the inlet valve or pump, said pulse indicative of the inlet valve opening
6. A method as claimed in claims 1 to 5 where in step c) the pumping chamber volume change is determined from the cam speed, cam profile, pumping chamber dimensions and the time points determined in steps a) and b).
10
7. A method as claimed in claims 1 to 6 where the pump system include a common rail connected to the outlet of the pumping chamber, said common rail including a pressure sensor and where the outlet pressure determined in step is measured form said pressure sensor.
GB1718312.0A 2017-11-06 2017-11-06 Method for determining the bulk modulus of a fuel Withdrawn GB2568090A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB1718312.0A GB2568090A (en) 2017-11-06 2017-11-06 Method for determining the bulk modulus of a fuel
PCT/EP2018/080148 WO2019086659A1 (en) 2017-11-06 2018-11-05 Method for determining the bulk modulus of a fuel

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1718312.0A GB2568090A (en) 2017-11-06 2017-11-06 Method for determining the bulk modulus of a fuel

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GB201718312D0 GB201718312D0 (en) 2017-12-20
GB2568090A true GB2568090A (en) 2019-05-08

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GB1718312.0A Withdrawn GB2568090A (en) 2017-11-06 2017-11-06 Method for determining the bulk modulus of a fuel

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WO (1) WO2019086659A1 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US12523182B2 (en) 2024-07-08 2026-01-13 Caterpillar Inc. Fuel injector control strategy using fuel bulk modulus for fuel injector command determination

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080035119A1 (en) * 2006-08-11 2008-02-14 Marriott Craig D System and method for determining ethanol content in fuel
US20100324803A1 (en) * 2009-06-19 2010-12-23 Denso Corporation Data storage device
EP2835518A1 (en) * 2013-08-05 2015-02-11 Delphi International Operations Luxembourg S.à r.l. Method to Determine Bulk Modulus of a Fuel
WO2015069171A1 (en) * 2013-11-08 2015-05-14 Scania Cv Ab Ethod for determining the bulk modulus of fuels

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102012107596B4 (en) * 2012-08-20 2016-05-04 Denso Corporation High pressure pump and method for operating a high pressure pump
DE102012223645B3 (en) * 2012-12-18 2014-02-27 Continental Automotive Gmbh Method for operating e.g. diesel injection system for diesel engine, involves decompressing fuel remaining in compression chamber, detecting opening time point of inlet valve, and determining bulk modulus of fuel based on time point
DE102014206442B4 (en) * 2014-04-03 2019-02-14 Continental Automotive Gmbh Method and device for operating a pressure accumulator, in particular for common rail injection systems in motor vehicle technology

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080035119A1 (en) * 2006-08-11 2008-02-14 Marriott Craig D System and method for determining ethanol content in fuel
US20100324803A1 (en) * 2009-06-19 2010-12-23 Denso Corporation Data storage device
EP2835518A1 (en) * 2013-08-05 2015-02-11 Delphi International Operations Luxembourg S.à r.l. Method to Determine Bulk Modulus of a Fuel
WO2015069171A1 (en) * 2013-11-08 2015-05-14 Scania Cv Ab Ethod for determining the bulk modulus of fuels

Also Published As

Publication number Publication date
WO2019086659A1 (en) 2019-05-09
GB201718312D0 (en) 2017-12-20

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Owner name: DELPHI TECHNOLOGIES IP LIMITED

Free format text: FORMER OWNER: DELPHI INTERNATIONAL OPERATIONS LUXEMBOURG S.A.R.L.

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