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Publication Date: 2015-Sep-10
Document File: 1 page(s) / 231K

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The Prior Art Database

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Engine fuel rail is typically pressurized to 50 psi during fuel pump activation. When the fuel pump is turned off, the pressure inside the fuel rail maintains at 50 psi for quite a while until the fuel cools off.There are circumstances when the fuel rail pressure needs to be depressurized down to zero psi.Prior model years had a Schrader valve on the fuel rail to facilitate depressurization.During a service procedure involving the fuel rail, injectors, etc., technicians typically depressurize the fuel rail by disconnecting the fuel rail relay and starting the engine until the fuel rail is depressurized.This method is intrusive as it requires technician to tamper with the vehicle electrical controls by removing and inserting the fuel pump relay. Another circumstance where it is beneficial to depressurize the fuel rail is vehicle during or post-crash event.Vehicles typically contain crash sensors interfaced to the restraint control module (RCM).Current Fuel Cut Off strategy relies on the changes of the vehicle accelerations level during the impact and air bag deployment methodology.If crash is detected and fuel cut off calibrated criteria is met, then RCM sends a message with different frequency to the powertrain module, which commands the fuel pump shut off. Additionally, when the fuel heats up, pressure may increase within the fuel system, and it may be desirable to maintain or decrease the fuel pressure.


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