Rotary kinetic fluid motors or pumps – With means for re-entry of working fluid to blade set – Turbine regenerative pump
Reexamination Certificate
2002-07-30
2004-03-09
Look, Edward K. (Department: 3745)
Rotary kinetic fluid motors or pumps
With means for re-entry of working fluid to blade set
Turbine regenerative pump
Reexamination Certificate
active
06702546
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATION
This application is based upon, claims the benefit of priority of, and incorporates by reference, the contents of Japanese Patent Applications No. 2001-232749 filed Jul. 31, 2001 and No. 2002-124745 filed Apr. 25, 2002.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a turbine fuel pump for pressure-feeding fuel from a fuel tank to a fuel injection apparatus on a vehicle.
2. Description of the Related Art
A turbine fuel pump may be used for pressure-feeding fuel in a fuel tank to a fuel injection apparatus on a vehicle such as an automobile. The turbine fuel pump (also referred to as a “Westco pump”) generally includes a disk-shaped impeller having multiple blades and blade grooves alternately formed along the circumference on an outer peripheral surface of the impeller, a motor housing that has C-shaped pump flow passages communicating to the blade grooves and that also stores the rotating impeller, and a motor for driving the impeller.
There have been needs for increasing the efficiency of a fuel supply apparatus including a fuel pump in view of decreasing fuel consumption of vehicles and atomizing fuel for low emissions. For these purposes, the shape of the blades and the blade grooves of the impeller, and the shape of a fuel outlet opening to which a terminal end of a pump flow passage of the motor housing communicates, have been improved.
However, a smooth flow of fuel at a fuel inlet opening, with which a start end of the pump passage of the motor housing communicates, has not been sufficiently studied. For example, in a turbine fuel pump in FIG.
12
and
FIG. 13
(see Japanese Patent Laid-Open Publication No. Hei. 11-117890), a motor housing
120
is attached to a pump housing
135
, and comprises a pump cover
122
on one side (a bottom side)
131
of the impeller
130
, and a pump casing
126
on the other side (a top side)
132
of the impeller
130
.
The pump cover
122
and the pump casing
126
form a circular impeller storage space, and a C-shaped pump flow passage
125
. A fuel inlet opening
123
is formed on the pump cover
122
for communicating to a start end
125
a
. A fuel outlet opening
127
is formed on the pump casing
126
for communicating to a terminal end
125
b
of the pump flow passage
125
. The impeller
130
has multiple blades
133
and blade grooves
134
alternately formed on an outer periphery, and is stored in the impeller storage space. The blade grooves
134
communicate to the pump flow passage
125
.
The fuel inlet opening
123
passes through the pump cover
122
in the axial direction (in the vertical direction in FIG.
12
). Thus, the flow direction of the fuel drawn from the fuel inlet opening
123
into the start end
125
a
is orthogonal to the rotational direction of the impeller
130
, and is orthogonal to the flow direction of the fuel in the pump flow passage
125
. The direction of the fuel flow changes by almost a right angle at the start end
125
a.
As a result, the flow rate of the fuel decreases at the start end
125
a
, and a loss of pressure (a pressure loss) is generated in the fuel. Consequently, a local negative pressure is generated in the fuel pressure at the start end
125
a
, a part of the fuel is vaporized, and the flow quantity decreases accordingly in the pump flow passage
125
. Especially when the temperature of the fuel is high, the local negative pressure increases the effect of vaporizing the fuel, and the flow quantity of the fuel markedly decreases.
Then, the flow quantity of the pressure-fed fuel from the start end
125
a
to the terminal end
125
b
decreases, and the outlet quantity from the fuel outlet opening
127
decreases. Thus, problems such as the pump efficiency scarcely increases, and the pump performance decreases when the fuel temperature is high.
SUMMARY OF THE INVENTION
The present invention was devised in view of the above problems, and an object is to provide a turbine fuel pump for preventing a pressure loss at the start end of the pump flow passage and for preventing the accompanying resultant local negative pressure. Additionally, increasing pump efficiency and overall operating performance while at a high temperature is a goal.
The present inventor studied a constitution of a first housing where a direction of drawing the fuel at the start end of the side groove on the inlet side is not orthogonal to the rotational direction of the impeller, and is not orthogonal to the fuel flow direction in the side groove on the inlet side. As a result, such an idea as the fuel inlet opening not being made as a port (an opening) but as a fuel inlet passage having a predetermined length was devised resulting in completion of the present invention.
A turbine fuel pump of a first aspect of the present invention includes a disk-shaped impeller provided with multiple blades and multiple blade grooves formed alternately around a circumference on a first surface and on an outer periphery of the second surface, and a pump housing for storing the impeller during rotation.
The pump housing includes a disk-like first housing provided on a first side of the impeller, and a disk-like second housing provided on a second side of the impeller. The first housing includes a side groove on an inlet side, and a fuel inlet passage. The side groove on the inlet side is formed on an inner side surface of the first housing, and extends from a start end to a terminal end in approximately a C-shape.
The fuel inlet passage extends from the start end of the side groove on the inlet side toward the inside in the radial direction, and simultaneously toward the terminal end, and has an opening on an outer side surface of the first housing. The second housing includes a side groove on an outlet side, and a fuel outlet opening. The side groove on an outlet side is formed on an inner side surface of the second housing, and extends from a start end to a terminal end in approximately a C-shape. The fuel outlet opening communicates to the terminal end of the side groove on the outlet side. The impeller rotates to increase the pressure of fuel while the fuel drawn from the fuel inlet passage is being transported to the fuel outlet opening.
In this fuel pump, the fuel inlet passage extends from the start end toward the terminal end of the side groove on the inlet side, and has the opening on the outer side surface. Thus, the fuel flowing from the fuel inlet passage to the start end is not orthogonal to the fuel flow in the side groove on the inlet side, and is not orthogonal to the rotational direction of the impeller. As a result, the decrease of the flow rate when the inlet fuel merges is small, the loss of the pressure is prevented at the start end, and the inlet fuel smoothly merges with the fuel in the side groove on the inlet side. Additionally, since a centrifugal force is applied to the fuel in the fuel inlet passage, the fuel flow rate increases.
A turbine fuel pump of an eleventh aspect of the present invention includes a disk-shaped impeller provided with multiple blades and multiple blade grooves formed alternately in the circumferential direction on a first surface and on a second surface around an outer periphery. Additionally, a pump housing is provided for storing said rotating impeller. The pump housing includes a disk-like first housing provided on one side of the impeller, and a disk-like second housing provided on the other side of the impeller.
The first housing includes a side groove on an inlet side, and a fuel inlet passage. The side groove on the inlet side is formed on an inner side surface of the first housing, and extends from a start end to a terminal end in approximately a C-shape. The fuel inlet passage extends from the start end of the side groove on the inlet side to an opening on an outer side surface of the first housing. The opening is positioned on the inside of the start end in the radial direction, and simultaneously on a side close to the terminal end in the circumferential direction.
The second housing includes
Ito Motoya
Iwanari Eiji
Kusagaya Katsuhiko
Mori Yukio
Takagi Masatoshi
Denso Corporation
McAleenan J. M.
Nixon & Vanderhye P.C.
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