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IP.com Disclosure Number: IPCOM000246318D
Publication Date: 2016-May-27
Document File: 7 page(s) / 157K

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The IP.com Prior Art Database


A fuel injector test apparatus includes an LED, a control circuit, and a locking plug assembly. The locking plug assembly engages with an engine control unit (ECU) wire harness that is removably electrically coupled to an electronic fuel injector. In use, the fuel injector is de-coupled from the ECU, and the test apparatus is connected to the ECU in its place. The locking plug establishes a secure electrical connection with the ECU wire harness, to prevent it from unplugging from the harness due to engine vibration. The control circuit receives a voltage signal from the ECU, and if the voltage signal corresponds to an operational voltage signal for correct operation of the fuel injector, the LED is illuminated. Thereby, if the LED is illuminated, the operator is aware that the ECU is outputting a proper voltage signal for operating the fuel injector.

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The present invention is drawn to a method and apparatus for testing and verifying the output control voltage of an electronic fuel injector. Fuel injection testing devices are popular due to their ability to verify that fuel injectors are operating properly. Using a fuel injection testing device can help troubleshoot dead cylinders and fuel system issues. Traditional fuel injection testing devices use a sensor device with lead wires to attach the sensor to the electronic control unit (ECU). When the engine is turned on, if the ECU is properly sending voltage to the fuel injector, normal voltage control signals will be detected by the sensor device. Similarly, if the ECU is not properly sending voltage to the fuel injector, the sensor device will detect abnormal voltage control signals.

Fuel injection testing devices that give a visual aid when an injector is getting the proper voltage are advantageous because they produce a signal that is easily recognizable by either a technician or a craftsperson. A fuel injector test light works by taking a signal that is delivered to a fuel injector from the ECU and converting it to a light. If the ECU is sending the proper voltage to the fuel injector, then the test light will flash regularly, and a technician or craftsperson can conclude that the system is operating properly. If the ECU is not sending the proper voltage to the fuel injector, then the test light will not light up or flash, indicating that repair or service is needed to troubleshoot fuel system issues.

One problem users of fuel injection testing devices may encounter is an unsecure connection between the electronic fuel injection harness and the test light sensor. If this connection is unsecure, vibrations exhibited by the engine when the engine is operating may cause the connection to fail, which would render the fuel injection test light ineffective. This problem is solved by the present invention as described herein.


Figure 1 is a schematic depiction of a fuel injector test light.

Figure 2 is a schematic depiction of the assembly of the male end of a fuel injector test light.

Figure 3 illustrates an example of how to use a fuel injector test light, wherein an injector is disconnected and the fuel injector test light is installed in its place.


            Embodiments of the present invention provide a method and apparatus for testing and verifying the output control voltage of an electronic fuel injector. The inventive apparatus is a fuel injector test light, comprising a light-emitting diode (LED), which can be viewed in Figure 1. The apparatus works by taking a voltage supplied by the ECU, up to 74 volts DC, and converting it into a light, which acts as a visual indicator that the ECU is firing voltage properly. This apparatus can be used on, but its use is not limited to, fuel injection engines upon rail vehicles. A...