Injection-amount measuring unit

Details Injection-amount measuring unit Injection-amount measuring unit

2002-04-29

2004-11-16

McCall, Eric S. (Department: 2855)

Measuring and testing

Internal combustion engine or related engine system or...

Compression

Reexamination Certificate

active

06817233

ABSTRACT:

CROSS REFERENCE TO RELATED APPLICATION
This application is based on, and claims the benefit of priority of, prior Japanese Patent Application No. 2001-132571 filed on Apr. 27, 2001, the contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an injection-amount measuring unit for measuring a fuel-injection amount of a fuel injector.
2. Description of Related Art
An injection-amount measuring device shown in
FIG. 3
is a main part of an injection-amount measuring unit
110
for measuring an injection amount of an injector
100
. A test fluid is supplied to the injector
100
from a pump (not shown) and the like through a fluid supply passage
115
. A noncombustible fluid, substantially having the same viscosity as fuel, is used as the test fluid to prevent the test fluid from catching on fire, burning, and the like.
The injector
100
injects the test fluid from an injection hole
104
by detaching a needle
102
from a valve seat. That is, the needle
102
breaks contact with the valve seat
103
. The needle
102
detaches from the valve seat
103
against an applied force of a spring
106
by energizing a coil
105
. The spring
106
applies the force to the needle
102
in a direction where the needle
102
is seated on the valve seat
103
that is, in a direction causing the injection hole to close. The applied force of the spring
106
is adjusted using a feed distance of an adjusting pipe
107
. The adjusting pipe
107
is guided by and enclosed within a housing
101
.
The force of the spring
112
is applied to a valve member
111
of the injection-amount measuring device in a downward direction in FIG.
3
. The valve member
111
is moved upward in
FIG. 3
by attaching the injector
100
to the injection-amount measuring device
110
so that a fluid passage
116
provided in the valve member
111
communicates with the fluid supply passage
115
. A flow meter
120
measures an amount of the test fluid flowing in the fluid supply passage
115
that is, an injection amount of the injector
100
. A pressure gage
121
measures a pressure of the test fluid flowing in the fluid supply passage
115
.
The needle
102
is made to reciprocate by supplying a pulse current shown in
FIG. 4
to the coil
105
. When the needle
102
is repeatedly seated on and detached from the valve seat
103
using an ON current and an OFF current of the pulse current, transmitted waves and reflected waves are generated
100
in the fluid within the injector. Then, as shown in
FIG. 4
, pressure pulsation is generated in the fluid within the injector. When the pressure pulsation is generated in the test fluid, the measured injection amount may fluctuate for every injection of the injector. The injection amount of injector can be accurately measured by increasing the number of injections and calculating an average injection amount. However, it takes a relatively long time to measure the injection amount in this manner.
A frequency of the pressure pulsation, a pressure wave shape and a pressure wave amplitude thereof are changed by a length, arrangement structure, and the like of piping for supplying the test fluid to the injector. Here, plural injection-amount measuring units are set, and a length, arrangement structure, and the like of piping for supplying the test fluid to the injector are changed for every injection-amount measuring unit. In this case, a frequency of the pressure pulsation, a pressure wave shape thereof and a pressure wave amplitude thereof are changed for every injection-amount measuring unit.
When the pressure pulsation of the test fluid injected by the injector is changed for every injection-amount measuring unit, the following trouble occurs. That is, even when a pulse current having the same pulse width and the same amplitude is applied to the coil of the same injector, and the test fluid having the same pressure is supplied, a measured result of the injection amount is changed for every injection-amount measuring unit. Further, when a measurement set value such as the pulse current and the test fluid pressure is changed, the measured injection amount using the changed measurement set value is sometimes changed for every injection-amount measuring unit.
SUMMARY OF THE INVENTION
Therefore, it is an object of the present invention to provide an injection-amount measuring unit for accurately measuring an injection amount of an injector in a relatively short period of time. It is another object of the present invention to provide an injection-amount measuring unit for measuring an injection amount which does not change for every injection-amount measuring unit.
In an injection-amount measuring unit according to an embodiment of the present invention, a passage area of a volume enlargement chamber is larger than a fluid inflow passage and a fluid outflow passage. Here, a fluid flows from a side of a fluid supply device into the volume enlargement chamber through the fluid inflow passage, and a fluid flows from the volume enlargement chamber to a side of a fuel injector (injector) through the fluid outflow passage. When a valve member of the injector performs intermittent fuel-injection, a pulsating pressure is generated in a fluid within the injector. When the pressure pulsation reaches the volume enlargement chamber from the fluid outflow passage, the pressure pulsation is reduced. That is, while a fluid is injected from the injector, fluctuating pressures of a fluid supplied to the injector can be reduced. Therefore, an injection amount can be accurately measured using a small number of injections, thereby performing a measuring operation in a small amount of time.
Here, multiple injection-amount measuring units are set, and a passage member changes in length and curvature for every injection-amount measuring device. Even in this case, when a pressure of a fluid supplied to the injector and a control current supplied to the electric driving member are set at the same values for every injection-amount measurement, injection-amount fluctuation of the injector is reduced for every injection-amount measuring unit. Accordingly, a degree of freedom of a set condition of the injection-amount measuring unit can be increased. In an injection-amount measuring unit according to an embodiment of the present invention, a feed distance of an adjusting pipe is adjusted so that a requested injection amount can be realized while the injection amount is measured. Accordingly, the injection amount of the injector can be adjusted in a small amount of time.
In an injection-amount measuring unit according to an embodiment of the present invention, the volume enlargement chamber is provided around a fuel inlet of the injector. Accordingly, the pressure pulsation generated in the fluid within the injector is immediately reduced. Here, multiple injection-amount measuring units are provided, and the passage member changes in length and curvature for every injection-amount measuring unit. Even in this case, when a pressure of a fluid supplied to the injector and a control current supplied to the electric driving member are set at the same values for every injection-amount measuring unit, injection-amount fluctuation of the injector can be further reduced for every injection-amount measuring unit.
In an injection-amount measuring unit according to an embodiment of the present invention, the fluid inflow passage and the fluid outflow passage are provided on lines different from each other, respectively. That is, the fluid inflow passage and the fluid outflow passage are not in the same line. Accordingly, the pressure pulsation can be effectively reduced in the volume enlargement chamber.
In an injection-amount measuring unit of an embodiment of the present invention, the fluid inflow passage and the fluid outflow passage are perpendicular to each other. Therefore, the pressure pulsation, transmitted from the injector into the volume enlargement chamber through the fluid outflow passage, experiences difficulty in tran

Affiliated with

Also associated with

Rating

Injection-amount measuring unit does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Injection-amount measuring unit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Injection-amount measuring unit will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3345768