Fluid handling – Self-proportioning or correlating systems – Self-controlled branched flow systems
Reexamination Certificate
1999-10-27
2001-09-25
Hepperle, Stephen M. (Department: 3753)
Fluid handling
Self-proportioning or correlating systems
Self-controlled branched flow systems
C123S514000, C137S115260, C137S544000, C137S563000
Reexamination Certificate
active
06293296
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a high-pressure fuel pump device comprising a high-pressure pump and a high-pressure regulator.
2. Description of the Prior Art
Diesel engines are widely known as an example of the engine technology that the fuel is injected into its cylinders, which is so called “in-cylinder injection engine” or “direct injection engine”. For spark ignition (gasoline) engines also, in-cylinder injection types have recently been proposed. For gasoline engines, there have been recently implemented in-cylinder injection type engines. For example, a high-pressure fuel pump device comprising a high-pressure pump and a high-pressure regulator is disclosed by Japanese Patent Publication No. 2689226.
FIG. 14
is a schematic diagram showing an automobile fuel supply system disclosed by the above publication. In
FIG. 14
, reference numeral
1
denotes a delivery pipe which is a fuel injection unit,
2
injectors corresponding to the number of the cylinders of an engine
3
,
4
a high-pressure fuel pump device attached to the housing of the engine
3
,
5
a first housing of the high-pressure fuel pump device
4
,
6
a second housing of the high-pressure fuel pump device
4
,
7
a connection portion between the first housing
5
and the second housing
6
,
8
a high-pressure pump for increasing the pressure of fuel to a high level, and
9
a pumping element
9
incorporated in the first housing
5
. The pumping element
9
has such elements as a piston driven by an unshown cam which turns at a half speed of the crank speed of the engine
3
and a cylinder for holding the piston in such a manner that it can reciprocate. Denoted by
10
is an intake valve arranged at the connection portion
7
,
11
a discharge valve arranged at the connection portion
7
,
12
a high-pressure regulator incorporated in the second housing
6
, for adjusting the pressure of fuel by draining part of high-pressure fuel,
13
a low-pressure passage formed in the first housing
5
,
14
a low-pressure passage of the second housing side formed in the second housing
6
,
15
a high-pressure passage on the first housing side formed in the first housing
5
,
16
a first high-pressure passage on the second housing side formed in the second housing
6
,
17
a second high-pressure passage on the second housing side formed in the second housing
6
,
18
a drain return passage formed in the second housing
6
,
19
a fuel tank,
20
a low-pressure pump stored in the fuel tank
19
,
21
a low-pressure pipe connected to the outlet portion of the low-pressure pump
20
and to the low-pressure passage
14
on the second housing side,
22
a high-pressure pipe connected to the high-pressure passage
16
on the second housing side and to the inlet portion of the delivery pipe
1
,
23
a high-pressure pipe connected to the outlet portion of the delivery pipe
1
and to the second high-pressure passage
17
on the second housing side,
24
a drain return pipe connected to the drain return passage
18
and to the fuel tank
19
, and
25
fuel stored in the fuel tank
19
. The high-pressure pump
8
is composed of such elements as the first housing
5
, the second housing
6
, the pumping element
9
, the intake valve
10
, the discharge valve
11
, the low-pressure passage
13
on the first housing side and the high-pressure passage
15
on the first housing side.
A description is subsequently given of the operation of the above fuel supply system. The low-pressure pump
20
sucks the fuel
25
and increases the pressure of the fuel to a low level. This low-pressure fuel
25
is sucked into the pumping element
9
from the low-pressure pipe
21
through the low-pressure passage
14
on the second housing side, the intake valve
10
and the low-pressure passage
13
on the first housing side. The pumping element
9
increases the pressure of the sucked fuel
25
to a high level and discharges it. This high-pressure fuel
25
is supplied to the delivery pipe
1
through the high-pressure passage
15
on the first housing side, the discharge valve
11
, the first high-pressure passage
16
on the second housing side and the high-pressure pipe
22
. At the fuel injection timing of each cylinder of the engine
3
, the corresponding injector
2
injects the high-pressure fuel
25
into the cylinder of the fuel injection timing. When the pressure of the fuel
25
supplied to the second high-pressure passage
17
on the second housing side from the delivery pipe
1
through the high-pressure pipe
23
exceeds a predetermined level set by the high-pressure regulator
12
, the high-pressure regulator
12
drains part of the fuel
25
in the second high-pressure passage
17
on the second housing side to control the pressure of the fuel supplied to the delivery pipe
1
from the pumping element
9
at a predetermined high level. This drained fuel
25
is returned to the fuel tank
19
from the drain return passage
18
through the drain return pipe
24
.
The above high-pressure fuel pump device
4
of the prior art is structured such that the high-pressure pump
8
includes part of the connection portion
7
, that is, the intake valve
10
and the discharge valve
11
are arranged in the connection portion
7
between the first housing
5
and the second housing
6
. The high-pressure pump
8
can be a single-cylinder pump having only one piston in the pumping element
9
or a multi-cylinder pump having multiple pistons in the pumping element
9
, while the high-pressure regulator
12
can be of a mechanical type for controlling the pressure of fuel to a fixed level or of an electromagnetic type for controlling the pressure of fuel to a variable level. Therefore, with the above mentioned high-pressure pump device
4
, it has been difficult to standardize the design of the first housing
5
and/or the second housing
6
per technologies used for the high-pressure pump
8
, single-cylinder or multi-cylinder, and per the technologies used for the high-pressure regulator
12
, mechanical type or electromagnetic type.
SUMMARY OF THE INVENTION
It is an object of the invention to solve the above problem by providing a high-pressure pump device which can facilitate the assembly of a high-pressure and a high-pressure regulator by standardizing a pump body or valve housing.
According to a first aspect of the present invention, there is provided a high-pressure pump device comprising a high-pressure pump for increasing the pressure of fuel to a high level and a high-pressure regulator for controlling the pressure of fuel by draining part of fuel discharged from the high-pressure pump, wherein the pump body of the high-pressure pump has a high-pressure valve connection portion including a high-pressure passage on the exterior side and used to connect the high-pressure regulator, the valve housing of the high-pressure regulator has a high-pressure pump connection portion including a high-pressure passage on the exterior side and used to connect the high-pressure pump, and those high-pressure connection portions are connected to each other to assemble the high-pressure pump and the high-pressure regulator together.
According to a second aspect of the present invention, there is provided a high-pressure pump device, wherein the high-pressure connection portions on the pump body and on the valve housing are connected to each other by mating.
According to a third aspect of the present invention, there is provided a high-pressure pump device, wherein the pump body has a low-pressure valve connection portion including a low-pressure passage on the exterior side, the valve housing has a low-pressure connection portion including a low-pressure passage on the exterior side, and those low-pressure connection portions are connected to each other and the high-pressure connection portions are connected to each other when the high-pressure pump and the high-pressure regulator are assembled together.
According to a fourth aspect of the present invention, there is provided a high-pressur
Fujita Masahiko
Konishi Keiichi
Miyaji Wakaki
Morishita Akira
Hepperle Stephen M.
Mitsubishi Denki & Kabushiki Kaisha
Sughrue Mion Zinn Macpeak & Seas, PLLC
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