Measuring and testing – Instrument proving or calibrating – Fluid pressure
Reexamination Certificate
1997-09-05
2001-05-22
Raevis, Robert (Department: 2856)
Measuring and testing
Instrument proving or calibrating
Fluid pressure
C073S114220, C073S865800, C239S106000, C239S112000, C239S113000, C134S022100, C134S022110, C134S022120, C134S022180, C134S0570DL, C134S0580DL, C134S084000, C134S089000, C134S16600C, C134S16900A, C134S16900A, C134S023000, C134S025100
Reexamination Certificate
active
06234002
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to diagnostic equipment and service of fuel delivery units such as conventional solenoid-operated fuel injectors of the type commonly used in internal combustion engines and diesel engines, and in land, marine and other applications. More specifically, the invention relates to apparatus and methods for cleaning and testing the performance of such fuel injectors.
Fuel injectors of this type include a relatively small flow passage and a small in-line poppet valve that is pulsed open and closed at high frequency by an integral solenoid coil to provide fuel flow to the engine. Several known abnormal conditions in these components result in inefficient engine performance.
Fuel contaminants passing through the fuel filter may build-up in the passage of an injector and restrict fuel flow from that injector. Entrapment of such contaminants in the poppet valve may prevent the valve from fully closing, resulting in excess fuel flow. And electrical failure of the solenoid results in an inoperative injector, and again no fuel delivery from that injector. Each of these conditions may result in inefficient engine performance, from, among other things, an improper fuel-air interpretation and compensation in the engine.
Numerous prior devices have been utilized for checking the flow rate through fuel injectors and cleaning the injectors by flowing a cleaning agent therethrough in normal and sometimes reverse direction. One prior method for testing flow rate includes placing the injector into a device adapted to capture the output flow in a graduated cylinder. The flow rate is then determined by the volume of fluid collected in the cylinder over a measured period of time. See e.g., Bunch, U.S. Pat. No. 5,000,043. The method of flow measurement utilized in Hart et al., U.S. Pat. No. 5,020,326 includes taking pressure readings with a “standard” fuel injector and then comparing those pressure readings (or calculations therefrom) with data collected from injectors in the automobile. Hartopp, U.S. Pat. No. 4,804,005 discloses a device with a conventional mechanical flow meter that may be switched into and out of an injector fluid flow circuit for measuring the flow rate. The prior art also teaches apparatus and methods for verifying that the spray angle from an injector appears correct. See e.g., Griggs, U.S. Pat. No. 5,571,959. Unfortunately, these prior methods and devices for checking and cleaning fuel injectors are labor intensive, and require the vigilant observation and participation of a trained technician to obtain reasonably accurate and repeatable results.
In addition, verifying that the resistance of the solenoid coil is within pre-defined limits, and that the coil is functioning properly, is typically accomplished via conventional electrical testing on individual injectors, again requiring the active participation of the service technician.
SUMMARY OF THE INVENTION
The general aim of the present invention is to provide new and improved apparatus and methods for cleaning and testing the performance of fuel delivery units such as fuel injectors, the methods providing for and the apparatus being uniquely adapted for automated operation, for establishing relatively precise and repeatable data collection and performance verification, and for preferably providing both visual indication and a printed record of injector performance.
A detailed objective is to achieve the foregoing by providing apparatus for selective operation between a testing mode and a cleaning mode, either mode being conducted, including the printing of performance data upon completion, by simply selecting either the “test” position or the “clean” position of a control switch.
A more detailed objective is to provide a micro-controller programmed to control operation of the apparatus and injectors, the micro-controller being operably connected to an electronic flow sensor and to a current sensing circuit for detecting injector flow rate and solenoid current draw data, respectively.
These and other objectives and advantages of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
In one embodiment of the invention, the apparatus includes, means for releasably receiving a plurality of fuel injectors, the switch to select either the test mode or clean mode of operation, and a fluid pumping system to provide a flow of cleaning fluid to the injectors. In this instance, an electric motor driven pump supplies pressurized cleaning fluid to a manifold which interconnects and supplies fluid to the injectors.
Automated control of the apparatus is accomplished with the pre-programmed micro-processor or micro-controller chip which energizes the injector solenoids in sequence, and according to the mode of operation selected.
The electronic flow meter is located in the fluid line between the pump and the manifold, and the current sensing circuit is wired to a common solenoid return wire. Visual display apparatus provide the service technician with continuous flow and current draw data from the flow and current detecting components. In addition, the flow and current data are periodically printed onto a paper strip to provide a permanent record of injector performance.
REFERENCES:
patent: 3478580 (1969-11-01), Siemietkowski et al.
patent: 4088012 (1978-05-01), Emerson
patent: 4218744 (1980-08-01), Pratt et al.
patent: 4712421 (1987-12-01), Young
patent: 4756186 (1988-07-01), Sangawa
patent: 4804005 (1989-02-01), Hartopp
patent: 4845979 (1989-07-01), Farenden et al.
patent: 5000042 (1991-03-01), Luebbering
patent: 5000043 (1991-03-01), Bunch, Jr. et al.
patent: 5020362 (1991-06-01), Hart et al.
patent: 5301113 (1994-04-01), To et al.
patent: 5571959 (1996-11-01), Griggs
Sisney David W.
Stauffer Paul E.
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