Internal-combustion engines – Charge forming device – Fuel flow regulation between the pump and the charge-forming...
Reexamination Certificate
1999-10-29
2001-08-07
Dolinar, Andrew M. (Department: 3747)
Internal-combustion engines
Charge forming device
Fuel flow regulation between the pump and the charge-forming...
C123S179170
Reexamination Certificate
active
06269801
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to diesel engines and, more particularly, to a system for priming a diesel fuel system.
BACKGROUND ART
Modern diesel fuel systems use an electronically controlled distributor injection pump. These injection pumps need a supplemental high capacity feed pump to deliver fuel to the vehicle fuel system. A typical cost effective feed pump to supply the amount of fuel required is an electrically driven roller vane or similar pump. Electrical energy to this pump is usually provided through a Powertrain Control Module (PCM) or Engine Electronic Controller (EEC).
Providing power through the electronic controller permits several advantages. These advantages include emergency shut down of the fuel pump in the event of an accident, using an inertia switch, to prevent fuel spills. Additionally, the fuel pump can be de-energized, if the key is in the on position, without the engine running. This prevents fuel pump overheating, due to absence of fuel flow. This also prevents excessive noise from the fuel pump, battery drain, and allows maximum electrical energy for starting aids, such as glowplugs. Of course, the pump runs continuously while the engine in running under normal operating conditions.
Unfortunately, if the electric pump is stationary, it usually (roller vane type) will not permit fuel to pass. This renders any manual attempt at priming the vehicle fuel system (removing any air in the fuel system) very difficult. The typical production method of removing air is using a dedicated downstream port, to apply a vacuum.
The typical service method (used after a fuel filter change, or accidentally running out of fuel), is to open a downstream port (usually provided at the Fuel Injection Pump or Main Fuel Filter), then run the electric pump, without running the engine, to purge the air from the system.
Because the fuel pump is NOT designed to run continuously with key on, engine off. Additional hardware has been proposed to allow priming of a diesel fuel system. The additional hardware includes dedicated software in a service tool, to be plugged into a diagnostic connector, an additional feed pump jumper wiring harness, or wiring communicating with the engine bay service light, that would permit the pump to run continuously, with the hood (bonnet) open and the key on.
Each of the above scenarios increases cost and reduces reliability of the overall vehicle. Thus, there exists a need to improve diesel fuel system priming.
SUMMARY OF THE INVENTION
It is an object of the invention to provide an improved and reliable means for priming a diesel fuel system. Another object of the invention is to allow diesel fuel system priming without the need for additional hardware.
In one aspect of the invention, an apparatus for priming a diesel fuel system includes a diesel engine having a plurality of injectors. The injectors receive a supply of diesel fuel from a fuel injection pump. A fuel feed pump supplies diesel fuel to the fuel injection pump. A controller energizes the fuel feed pump during an initial operating time period. The controller then de-energizes the fuel pump during a second operating time period to prevent heat build up, noise, and battery drain. The controller then energizes the fuel feed pump during a priming time period, allowing the diesel fuel system to be primed with diesel fuel. The controller then de-energizes the fuel pump after the priming time period to prevent heat build up, noise, and battery drain.
The present invention achieves an improved and reliable means for priming a diesel fuel system. Also, the present invention is advantageous in that it accomplishes this goal without the need for additional hardware.
Additional advantages and features of the present invention will become apparent from the description that follows, and may be realized by means of the instrumentalities and combinations particularly pointed out in the appended claims, taken in conjunction with the accompanying drawings.
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Castro Arnold
Dolinar Andrew M.
Ford Global Technologies Inc.
Stec Jennifer
LandOfFree
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