Fuel preheat for engine start
Systems and methods for providing heated fuel to a fuel injector of an engine are provided. According to the approaches described herein, adequate cold-start fuel atomization may be provided without compromising driver satisfaction due to excessive pre-ignition delay, while at the same time reducing unnecessary heating of fuel during warm engine off conditions.
1. A method for providing heated fuel to a fuel injector of an engine in a motor vehicle, the method comprising:
maintaining a volume of fuel above a start-ready temperature during a pre-start interval, the pre-start interval beginning after the engine is turned off, beginning automatically, and ending when the engine is restarted, the start-ready temperature greater than a lowest temperature of the engine during the pre-start interval, the automatic beginning of the maintaining of the volume of fuel above the start-ready temperature beginning independent of action of an operator of the motor vehicle, the fuel maintained above the start-ready temperature being stored in a container, where fuel is pumped into the container from a fuel rail; and
delivering some of the volume of fuel maintained above the start-ready temperature to the fuel injector when the engine is about to be restarted.
2. The method of claim 1 , wherein the pre-start interval begins when the engine is turned off.
3. The method of claim 1 , wherein fuel injected at the start-ready temperature is not cold enough to impair emissions-control performance of the motor vehicle due to inadequate atomization.
4. The method of claim 1 , wherein maintaining the volume of fuel above the start-ready temperature includes heating the fuel.
5. The method of claim 1 , wherein maintaining the volume of fuel above the start-ready temperature further includes heating the fuel only if power is available to heat the fuel.
6. The method of claim 1 , wherein delivering some of the volume of fuel to the fuel injector is triggered by actuating an ignition switch of the motor vehicle or opening a driver's door of the motor vehicle.
7. A method for providing heated fuel to an engine fuel injector of a vehicle operated by a driver comprising:
in response to temperature dropping below a threshold, automatically heating fuel in a container to above engine temperature prior to any driver starting indication and independent of operator action, the fuel pumped into the container from a fuel rail coupled to the injector; and
delivering the heated fuel to the injector to restart the engine.
8. The method of claim 7 further comprising delivering fuel from the container to the fuel rail via a pressure-actuated valve.
9. The method of claim 7 , further comprising delivering fuel to the container via a pressure-actuated valve.
10. The method of claim 7 , further pumping the fuel from the fuel rail to the container when the engine is about to be restarted.
11. The method of claim 10 , further comprising exchanging fuel in the container with fuel in the fuel rail when the engine is about to be restarted.
12. The method of claim 10 , wherein fuel entering the container forces fuel maintained above the start-ready temperature into the fuel rail, which forces fuel from the fuel rail into a fuel-storage tank when the engine is about to be restarted.
13. A method for providing fuel to an engine of a vehicle, the vehicle including a fuel injector, a container configured to store fuel, a heater, a fuel-handling system coupled to the container, the fuel-handling system including a lift pump and a GDI fuel pump, and a fuel-storage tank, comprising;
maintaining, via the heater, a temperature of the fuel above a start-ready temperature during a pre-start interval, the pre-start interval beginning after the engine is turned off, beginning automatically, and ending when the engine is restarted, the start-ready temperature greater than a lowest temperature of the engine during the pre-start interval;
flowing, via the fuel-handling system, fuel from the container to the fuel injector when the engine is about to be restarted;
drawing fuel from the fuel-storage tank via the lift pump;
admitting fuel from a fuel rail of the engine to the fuel-storage tank when the engine is about to be restarted via a first normally closed valve configured;
supplying fuel to the fuel rail via the GDI pump;
admitting fuel from the container to the GDI pump via a second normally closed valve when the engine is about to be restarted; and
releasing fuel from the container via a one-way, pressure-actuated valve disposed parallel to the second normally closed valve.