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Diagnostic Method of Identifying Sticking or Delayed Opening of Fuel Injectors Disclosure Number: IPCOM000126108D
Publication Date: 2005-Jun-30
Document File: 1 page(s) / 30K

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The Prior Art Database

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Diagnostic Method of Identifying Sticking or Delayed Opening of Fuel Injectors

Fuel Injector Test Procedure

A method of testing fuel injectors that provides a means of identifying injectors that are "sticking" or have a delayed response (see Fig 1) to being commanded open/on. This method was developed as a result of testing field return NGV injectors that exhibited a delayed response to be commanded open due to oil contamination of the fuel system.

Fig 1

1. Existing injector flow tests can test injector flow rates and/or flow rates relative to other fuel injectors, but may fail to identify a mechanical "delayed opening" condition since once the injector opens, its actual rate of flow may be within expected limits.
2. A change in the existing injector flow test algorithm is implemented to monitor the time period from when the injector on commanded open (Key On Engine Off state) until a specific specified fuel pressure drop is detected.
3. Using this method in conjunction with established methods of measuring actual injector flow times, a mechanically sticking or delayed opening fuel injector can be identified.


a. This test method could be used on any vehicle application equipped with electrically controlled fuel injectors to detect unexpected mechanical delay of the actual opening of the fuel injector.
b. This test method can be integrated into an off-board diagnostic test tool using off-board instrumentation to monitor injector opening times, fuel p...