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
  • F02M65/005—Measuring or detecting injection-valve lift, e.g. to determine injection timing
• • 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
  • 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

Definitions

• 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 compairing 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.
• 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.
• 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 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.
• the transducer may be a directional microphone not actually in contact with the injector.
• 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.
• 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.
• 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.
• the acoustic waves associated with the opening of an injector have relatively 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.
• a band-pass filter preferably having a centre frequency of approximately 40 KHz, may be connected to the output of the transducer.
• the transducer is attached to the injector by-means of a spring clip. 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.
• the top dead centre position can be determined by a method and apparatus as disclosed in our copending application No. (reference 230P41477X) entitled "Improvements in or relating to methods of and apparatuses for indicating a predetermind 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.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Testing Of Engines (AREA)

Applications Claiming Priority (4)

Publications (1)

Family

ID=26277936

Family Applications (1)

Country Status (1)

Cited By (2)

Citations (4)

• 1981
  • 1981-12-18 EP EP81305960A patent/EP0055563A1/de not_active Withdrawn

Patent Citations (7)

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