Emissions Benefits of Ultra-High Injection Pressure: Stage 1 - Injection System Configuration, 03-9324

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Principal Investigator
Stefan Simescu

Lee G. Dodge

Inclusive Dates: 07/01/02 - 01/01/04

Background - Ultra-high injection pressures are believed necessary for reducing in-cylinder particulate matter emissions on diesel engines equipped with EGR systems. The objective of this project is to prepare a demonstration diesel fuel injection system that can operate at ultra-high injection pressures (200 to 300 MPa) independently of engine speed. Future planned work would be to adapt such a system to an engine and document the particulate matter reduction possibilities.

Approach - The following experimental investigation is performed on a high-pressure common rail injection system:

  • Document the effects of rail pressure on the performance of the injection nozzles;
  • Modify the injection nozzle design to accommodate the higher pressure;
  • Document the effects of high injection pressure on the spray characteristics (jet penetration rate, jet cone angle, liquid core length).

Ultra-high injection pressures are obtained by using a high-pressure intensifier, capable of rail pressures up to 275 MPa. The injection rate is determined using a commercial injection rate meter. The effect of injection pressure on the spray characteristics is determined by high-speed, digital imaging in a spray visualization pressure vessel. Three commercial common rail injectors were identified as potential candidates for this work. The maximum operating pressure for these injectors is first determined, and one injector will be selected for further investigation. Injector modifications will be implemented to allow ultra-high injection pressure operation. The modified injector operation at ultra-high pressure will be evaluated, in terms of injection rate and spray characteristics.

Accomplishments - The high-pressure intensifier was set up and provided injection pressures up to 200 MPa.

The injection rate meter was set up, and injection rate measurements were performed on three common rail injectors. Two of the injectors operated without modifications up to 200 MPa.

The intensifier is currently being modified to enable injection pressures up to 275 MPa.

The baseline characterization of the injectors is in progress. The selection of the injector for further investigation will follow the characterization tests.

A new spray visualization pressure vessel was designed and constructed. Its operation (including the high-speed digital imaging) was successfully demonstrated during a commercial project.

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