GB2089986A - Detecting fuel injector opening - Google Patents

Detecting fuel injector opening Download PDF

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Publication number
GB2089986A
GB2089986A GB8138392A GB8138392A GB2089986A GB 2089986 A GB2089986 A GB 2089986A GB 8138392 A GB8138392 A GB 8138392A GB 8138392 A GB8138392 A GB 8138392A GB 2089986 A GB2089986 A GB 2089986A
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GB
United Kingdom
Prior art keywords
injector
transducer
opening
engine
contact
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Withdrawn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
GB8138392A
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.)
FROUDE ENG Ltd
Original Assignee
FROUDE ENG 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 FROUDE ENG Ltd filed Critical FROUDE ENG Ltd
Priority to GB8138392A priority Critical patent/GB2089986A/en
Publication of GB2089986A publication Critical patent/GB2089986A/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Withdrawn legal-status Critical Current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
    • 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
    • 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
    • F02M65/005—Measuring or detecting injection-valve lift, e.g. to determine injection timing
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
    • G01H1/00—Measuring characteristics of vibrations in solids by using direct conduction to the detector
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B1/00—Engines characterised by fuel-air mixture compression
    • F02B1/02—Engines characterised by fuel-air mixture compression with positive ignition
    • F02B1/04—Engines characterised by fuel-air mixture compression with positive ignition with fuel-air mixture admission into cylinder
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B3/00—Engines characterised by air compression and subsequent fuel addition
    • F02B3/06—Engines characterised by air compression and subsequent fuel addition with compression ignition

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Fuel-Injection Apparatus (AREA)
  • Combined Controls Of Internal Combustion Engines (AREA)
  • Testing Of Engines (AREA)

Abstract

In order to determine the opening of a fuel injector of, for instance, a compression ignition engine, an electro-acoustic transducer such as a contact microphone monitors the acoustic waves produced by the injector. A monitoring circuit detects when the level of the output signals of the transducer increases, this increase being indicative of opening of the injector. By comparing the opening time of the injector with the position of the crankshaft, the timing of the engine can be checked without requiring dismantling.

Description

SPECIFICATION Improvements in or relating to methods of and apparatus for determining opening of injectors The present invention relates to methods of and apparatuses for determining opening of injectors.
Such methods and apparatuses may be used for determining when an injector of a compression ignition engine opens. By comparing this opening time with the position of the engine crankshaft, it is possible to check the timing of the engine without having to dismantle the engine to inspect the drive to the injector arrangement.
According to one aspect of the invention, there is provided a method of determining opening of an injector, comprising applying an electro-acoustic transducer to the injector and monitoring the level of the output signal of the transducer to detect an increase therein indicative of opening of the injector.
According to another aspect of the invention, there is provided an apparatus for determining opening of an injector, comprising an electroacoustic transducer arranged to be appiied to the injector and a monitoring circuit arranged to monitor the level of the output signal of the transducer to detect an increase therein indicative of opening of the injector.
The transducer may comprise a contact transducer arranged to be in contact with the injector. The contact transducer may be a contact microphone, for instance of the piezo-electric type which is sufficiently rugged and reliable for this type of use. Alternatively the transducer may be a directional microphone not actually in contact with the injector.
In the case of a fuel injector of a compression ignition or diesel engine, the sudden flow of fuel through the injector when it opens to inject fuel into a cylinder of the engine produces acoustic waves which propagate in the metal body of the injector. The transducer receives these waves and converts them into an electrical signal whose level, at least at some frequencies, increases when the injector opens. Thus, the time or rise of the amplitude of this signal corresponds to the time when the injector opens.
- The monitoring circuit monitors the output signal of the transducer, in particular the level thereof, and provides a signal indicative of the increase in amplitude corresponding to the opening of the injector. The monitoring circuit may include a filter allowing signals of frequencies corresponding to the sound produced by the injector when open to be preferentially amplified, thus increasing the signal-to-noise ratio or sensitivity of the monitoring circuit. Even when the engine is running normally and is thus producing a substantial amount of background noise, the monitoring circuit is still able to distinguish the acoustic waves produced by opening of the injector so as to produce a signal indicative of this opening.Thus the output signal from the transducer may be filtered so as to exclude noise or acoustic waves generated in other parts of the engine, thus permitting acoustic waves whose frequency is associated with the opening of the injector to be preferentially amplified.
It has been found that the acoustic waves associated with the opening of an injector have relativeiy high frequency. It is possible to use frequencies up to and in the region of 400 KHz.
The use of frequencies in the region of 40 KHz has been found to be particularly advantageous.
Accordingly, it is preferable for the output of the transducer to be filtered so as to pass signals having frequencies in such regions while suppressing or substantially reducing output signals whose frequencies lie outside these regions. Thus, a band-pass filter, preferably having a centre frequency of approximately 40 KHz, may be connected to the output of the transducer.
This permits more accurate detection of the opening of the injector in the presence of noise which is generated when the engine is being tested. In general, such noise has frequency components which lie outside these regions and thus may be removed or reduced sufficiently to allow a clear determination of opening of the injector to be made. Even when the noise has components, for instance, in the region of 40 KHz, it is still possible, for instance by arranging the transducer so as to be specifically sensitive to the acoustic waves produced by the injector while being much less sensitive to noise from other sources, to provide a signal with a sufficiently good signal-to-noise ratio to allow the opening of the injector to be reliably and accurately determined.
In a particularly simple embodiment of the invention, the transducer is attached to the injector by means of a spring ciip. This has been found in practice to provide an adequate attachment of the transducer to the injector, and provides a quick, simple, cheap and convenient means of attachment, allowing the transducer to be readily detached when desired.
The method and apparatus may be used in conjunction with means for determining the position of a piston or crankshaft of an internal combustion engine so that the timing of the engine can be checked. In cases where there is no mark on a flywheel of the engine indicating top dead centre of one of the pistons, the top dead centre position can be determined by a method and apparatus as disclosed in our copending application No. (reference 230P4 1 477X) entitled "Improvements in or relating to methods of and apparatuses for indicating a predetermined position of a piston or crankshaft of a piston engine", so that the engine timing can be checked without requiring any dismantling of the engine. The engine timing can thus be checked in a very quick and convenient manner.
1. A method of determining opening of an injector, comprising applying an electro-acoustic transducer to the injector and monitoring the level of the output signal of the transducer to detect an
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (18)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements in or relating to methods of and apparatus for determining opening of injectors The present invention relates to methods of and apparatuses for determining opening of injectors. Such methods and apparatuses may be used for determining when an injector of a compression ignition engine opens. By comparing this opening time with the position of the engine crankshaft, it is possible to check the timing of the engine without having to dismantle the engine to inspect the drive to the injector arrangement. According to one aspect of the invention, there is provided a method of determining opening of an injector, comprising applying an electro-acoustic transducer to the injector and monitoring the level of the output signal of the transducer to detect an increase therein indicative of opening of the injector. According to another aspect of the invention, there is provided an apparatus for determining opening of an injector, comprising an electroacoustic transducer arranged to be appiied to the injector and a monitoring circuit arranged to monitor the level of the output signal of the transducer to detect an increase therein indicative of opening of the injector. The transducer may comprise a contact transducer arranged to be in contact with the injector. The contact transducer may be a contact microphone, for instance of the piezo-electric type which is sufficiently rugged and reliable for this type of use. Alternatively the transducer may be a directional microphone not actually in contact with the injector. In the case of a fuel injector of a compression ignition or diesel engine, the sudden flow of fuel through the injector when it opens to inject fuel into a cylinder of the engine produces acoustic waves which propagate in the metal body of the injector. The transducer receives these waves and converts them into an electrical signal whose level, at least at some frequencies, increases when the injector opens. Thus, the time or rise of the amplitude of this signal corresponds to the time when the injector opens. - The monitoring circuit monitors the output signal of the transducer, in particular the level thereof, and provides a signal indicative of the increase in amplitude corresponding to the opening of the injector. The monitoring circuit may include a filter allowing signals of frequencies corresponding to the sound produced by the injector when open to be preferentially amplified, thus increasing the signal-to-noise ratio or sensitivity of the monitoring circuit. Even when the engine is running normally and is thus producing a substantial amount of background noise, the monitoring circuit is still able to distinguish the acoustic waves produced by opening of the injector so as to produce a signal indicative of this opening.Thus the output signal from the transducer may be filtered so as to exclude noise or acoustic waves generated in other parts of the engine, thus permitting acoustic waves whose frequency is associated with the opening of the injector to be preferentially amplified. It has been found that the acoustic waves associated with the opening of an injector have relativeiy high frequency. It is possible to use frequencies up to and in the region of 400 KHz. The use of frequencies in the region of 40 KHz has been found to be particularly advantageous. Accordingly, it is preferable for the output of the transducer to be filtered so as to pass signals having frequencies in such regions while suppressing or substantially reducing output signals whose frequencies lie outside these regions. Thus, a band-pass filter, preferably having a centre frequency of approximately 40 KHz, may be connected to the output of the transducer. This permits more accurate detection of the opening of the injector in the presence of noise which is generated when the engine is being tested. In general, such noise has frequency components which lie outside these regions and thus may be removed or reduced sufficiently to allow a clear determination of opening of the injector to be made. Even when the noise has components, for instance, in the region of 40 KHz, it is still possible, for instance by arranging the transducer so as to be specifically sensitive to the acoustic waves produced by the injector while being much less sensitive to noise from other sources, to provide a signal with a sufficiently good signal-to-noise ratio to allow the opening of the injector to be reliably and accurately determined. In a particularly simple embodiment of the invention, the transducer is attached to the injector by means of a spring ciip. This has been found in practice to provide an adequate attachment of the transducer to the injector, and provides a quick, simple, cheap and convenient means of attachment, allowing the transducer to be readily detached when desired. The method and apparatus may be used in conjunction with means for determining the position of a piston or crankshaft of an internal combustion engine so that the timing of the engine can be checked. In cases where there is no mark on a flywheel of the engine indicating top dead centre of one of the pistons, the top dead centre position can be determined by a method and apparatus as disclosed in our copending application No. (reference 230P4 1 477X) entitled "Improvements in or relating to methods of and apparatuses for indicating a predetermined position of a piston or crankshaft of a piston engine", so that the engine timing can be checked without requiring any dismantling of the engine. The engine timing can thus be checked in a very quick and convenient manner. CLAIMS
1. A method of determining opening of an injector, comprising applying an electro-acoustic transducer to the injector and monitoring the level of the output signal of the transducer to detect an increase therein indicative of opening of the injector.
2. A method as claimed in claim 1, in which a contact transducer is placed in contact with the injector.
3. A method as claimed in claim 2, in which the contact transducer is a contact microphone.
4. A method as claimed in claim 3, in which the contact microphone is of piezo-eiectric type.
5. A method as claimed in claim 1, in which the transducer is a directional microphone which is directed at the injector.
6. A method as claimed in any one of the preceding claims, in which the components of the output signal of the transducer having frequencies corresponding to the acoustic waves produced by the injector when open are monitored and components having other frequencies are substantially ignored.
7. A method as claimed in claim 6, in which components having frequencies up to substantially 400 KHz are monitored.
8. A method as claimed in claim 7, in which components having frequencies in the region of 40 KHz are monitored.
9. A method of determining openings of an injector substantially as hereinbefore described.
1 0. An apparatus for determining opening of an injector, comprising an electro-acoustic transducer arranged to be applied to the injector and a monitoring circuit arranged to monitor the level of the output signal of the transducer to detect an increase therein indicative of openings of the injector.
11. An apparatus as claimed in claim 9, in which the electro-acoustic transducer is a contact transducer.
12. An apparatus as claimed in claim 10, in which the contact transducer is a contact microphone.
13. An apparatus as claimed in claim 12, in which the contact microphone is of piezo-electric type.
14. An apparatus as claimed in any one of claims 11 to 13, in which the contact transducer is provided with a spring clip for attachment to the injector.
1 5. An apparatus as claimed in claim 10, in which the electro-acoustic transducer is a directional microphone.
1 6. An apparatus as claimed in any one of claims 10 to 15, in which the monitoring circuit includes a filter arranged to pass components of the output signal of the transducer having frequencies corresponding to the acoustic waves produced by the injector when open.
17. An apparatus as claimed in claim 16, in which the filter is arranged to pass components having frequencies up to substantially 400 KHz.
18. An apparatus as claimed in claim 17, in which the filter is a bandpass filter having a centre frequency of substantially 40 KHz.
1 9. An apparatus for determining opening of an injector substantially as hereinbefore described.
GB8138392A 1980-12-22 1981-12-21 Detecting fuel injector opening Withdrawn GB2089986A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB8138392A GB2089986A (en) 1980-12-22 1981-12-21 Detecting fuel injector opening

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8040969 1980-12-22
GB8138392A GB2089986A (en) 1980-12-22 1981-12-21 Detecting fuel injector opening

Publications (1)

Publication Number Publication Date
GB2089986A true GB2089986A (en) 1982-06-30

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Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2122350A (en) * 1982-05-12 1984-01-11 Avl Verbrennungskraft Messtech Checking valve clearances on a piston engine
GB2146119A (en) * 1983-09-05 1985-04-11 Froude Consine Ltd Detection of fuel injection
GB2189885A (en) * 1986-05-01 1987-11-04 Atomic Energy Authority Uk Turbulent flow monitoring
EP1703122A1 (en) * 2005-02-05 2006-09-20 L'orange Gmbh Method and apparatus for capturing with an acoustic sensor the injection process of an internal combustion engine
EP1762831A1 (en) * 2005-09-13 2007-03-14 Rolls-Royce plc Health monitoring of a mechanical system
WO2020132060A1 (en) * 2018-12-18 2020-06-25 Bongiovi Acoustics Llc A mechanical failure detection system and method
US10701505B2 (en) 2006-02-07 2020-06-30 Bongiovi Acoustics Llc. System, method, and apparatus for generating and digitally processing a head related audio transfer function
US10848118B2 (en) 2004-08-10 2020-11-24 Bongiovi Acoustics Llc System and method for digital signal processing
US10848867B2 (en) 2006-02-07 2020-11-24 Bongiovi Acoustics Llc System and method for digital signal processing
US10917722B2 (en) 2013-10-22 2021-02-09 Bongiovi Acoustics, Llc System and method for digital signal processing
US10959035B2 (en) 2018-08-02 2021-03-23 Bongiovi Acoustics Llc System, method, and apparatus for generating and digitally processing a head related audio transfer function
US10999695B2 (en) 2013-06-12 2021-05-04 Bongiovi Acoustics Llc System and method for stereo field enhancement in two channel audio systems
US11431312B2 (en) 2004-08-10 2022-08-30 Bongiovi Acoustics Llc System and method for digital signal processing
US12175960B2 (en) 2018-04-11 2024-12-24 Bongiovi Acoustic Llc Audio enhanced hearing protection system

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2122350A (en) * 1982-05-12 1984-01-11 Avl Verbrennungskraft Messtech Checking valve clearances on a piston engine
GB2146119A (en) * 1983-09-05 1985-04-11 Froude Consine Ltd Detection of fuel injection
GB2189885A (en) * 1986-05-01 1987-11-04 Atomic Energy Authority Uk Turbulent flow monitoring
US4791810A (en) * 1986-05-01 1988-12-20 United Kingdom Atomic Energy Authority Flow monitoring
GB2189885B (en) * 1986-05-01 1990-06-20 Atomic Energy Authority Uk Flow monitoring
US11431312B2 (en) 2004-08-10 2022-08-30 Bongiovi Acoustics Llc System and method for digital signal processing
US10848118B2 (en) 2004-08-10 2020-11-24 Bongiovi Acoustics Llc System and method for digital signal processing
EP1703122A1 (en) * 2005-02-05 2006-09-20 L'orange Gmbh Method and apparatus for capturing with an acoustic sensor the injection process of an internal combustion engine
EP1762831A1 (en) * 2005-09-13 2007-03-14 Rolls-Royce plc Health monitoring of a mechanical system
US7591183B2 (en) 2005-09-13 2009-09-22 Rolls-Royce Plc Gas turbine engine with a plurality of bleed valves
US10701505B2 (en) 2006-02-07 2020-06-30 Bongiovi Acoustics Llc. System, method, and apparatus for generating and digitally processing a head related audio transfer function
US10848867B2 (en) 2006-02-07 2020-11-24 Bongiovi Acoustics Llc System and method for digital signal processing
US11425499B2 (en) 2006-02-07 2022-08-23 Bongiovi Acoustics Llc System and method for digital signal processing
US10999695B2 (en) 2013-06-12 2021-05-04 Bongiovi Acoustics Llc System and method for stereo field enhancement in two channel audio systems
US10917722B2 (en) 2013-10-22 2021-02-09 Bongiovi Acoustics, Llc System and method for digital signal processing
US11418881B2 (en) 2013-10-22 2022-08-16 Bongiovi Acoustics Llc System and method for digital signal processing
US12175960B2 (en) 2018-04-11 2024-12-24 Bongiovi Acoustic Llc Audio enhanced hearing protection system
US10959035B2 (en) 2018-08-02 2021-03-23 Bongiovi Acoustics Llc System, method, and apparatus for generating and digitally processing a head related audio transfer function
WO2020132060A1 (en) * 2018-12-18 2020-06-25 Bongiovi Acoustics Llc A mechanical failure detection system and method

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