Internal-combustion engines – Charge forming device – Supercharger
Reexamination Certificate
2001-03-05
2002-03-12
Nguyen, Hoang (Department: 3748)
Internal-combustion engines
Charge forming device
Supercharger
C123S599000
Reexamination Certificate
active
06354282
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fuel limitation device for a diesel engine with a supercharger and particularly concerns a technique for inhibiting fuel increase at the time of quick acceleration by a diaphragm-type boost actuator, while securing a starting fuel increase.
2. Explanation of Related Art
There are conventionally known examples of the fuel limitation device for an engine with a supercharger such as shown in
FIG. 11
(prior art
1
) and in
FIG. 12
(prior art
2
).
As shown in
FIG. 11
, the prior art
1
comprises a fuel meter
21
of a fuel injection pump for an engine (E) with a supercharger, made movable for fuel metering through a double governor lever
14
of a centrifugal governor
10
. A swing lever
31
is supported by a pivot axis (Q) and has a power input point (J) which engages with an output rod
30
of a diaphragm-type boost actuator
26
. The swing lever
31
has a power output point (K) which faces the fuel meter
21
from a fuel increase side (R) of the fuel meter
21
. If the boost actuator
26
operates in response to a delayed rise of a pressure (P) supercharged to the engine (E), the power output point (K) of the swing lever
31
inhibits the fuel meter
21
from moving for fuel increase.
The boost actuator
26
projects the output rod
30
with the supercharged pressure (P) against a return spring
28
. Then it limits an excessive fuel supply caused by the delayed rise of the supercharged pressure (P) attributable to a rotation delay of the supercharger (turbo-charger) at the time of quick acceleration and the like to thereby prevent the generation of black smoke and the wasteful fuel consumption. Further, there is disposed a push rod (M) which strongly pushes out the fuel meter
21
to a starting fuel increase position against the return spring
28
of the boost actuator
26
when starting the engine (E). Here, in
FIG. 11
, numerals
2
and
3
designate a turbine and a compressor of the supercharger. Numeral
4
indicates a waste gate valve which reduces an excessive exhaust pressure caused by exhaust gas (C) produced at the time of a high-speed operation. Numerals
5
,
6
,
8
,
11
,
12
and
13
show an intake pipe, an exhaust pipe, a supercharged pressure communication pipe, a speed control operation lever, a speed control lever, and a governor spring, respectively. Numerals
14
a and
14
b indicate a first lever and a second lever forming a double governor lever
14
. Numeral
15
designates a pivot axis of the governor lever
14
. Numerals
16
,
18
and
46
show a torque-up device, a start spring and a governor sleeve, respectively.
As shown in
FIG. 12
, the prior art
2
comprises a fuel meter
21
of a fuel injection pump for an engine with a supercharger, made movable for fuel metering through a double governor lever
14
of a centrifugal governor
10
. A swing lever
31
is supported by a pivot axis (Q) and has a power input point (J) which engages with an output rod
30
of a diaphragm-type boost actuator
26
. The swing lever has a power output point (K) which faces the fuel meter
21
from a fuel increase side (R) of the fuel meter
21
. If the boost actuator
26
operates in response to a delayed rise of a pressure (P) supercharged to the engine (E), the power output point (K) of the swing lever
31
inhibits the fuel meter
21
from moving for fuel increase. An actuator
40
displaces the pivot axis (Q) to position the power output point (K) of the swing lever
31
on the fuel increase side (R) or a fuel decrease side (L). When making a cold start of the engine, the actuator
40
has its output rod
35
retracted to move the fuel meter
21
for fuel increase by the power output point (K) of the swing lever
31
, thereby cancelling a fuel limitation function of the boost actuator
26
. After the engine has started, the boost actuator
26
maintains the fuel limitation function.
SUMMARY OF THE INVENTION
According to the prior arts
1
and
2
, it is possible to prevent the generation of black smoke and the wasteful fuel consumption by limiting the excessive fuel supply attributable to the delayed rise of the supercharged pressure (P). However, they have to be still improved on the following points.
When starting the engine, since no boost pressure acts on the boost actuator
26
and the output rod
30
is retracted, the power output point (K) of the swing lever
31
prevents the fuel meter
21
of the fuel injection pump from moving to a starting fuel increase position.
Then the prior art
1
requires to separately provide a push rod (M) which pushes out the fuel meter
21
to the starting fuel increase position against the return spring
28
of the boost actuator
26
when starting the engine. This needs a strong driving force which pushes out the push rod (M) against the return spring
28
of the boost actuator
26
. On the other hand, if the fuel meter
21
always exists at the starting fuel increase position when starting the engine, excessive fuel is supplied at the time of making a warm start to result in entailing a problem of generating black smoke and consuming fuel wastefully.
Further, the prior art
2
retracts the output rod
35
of the actuator
40
, thereby enabling the power output point (K) of the swing lever
31
to move for fuel increase when starting the engine. Therefore, it can solve the disadvantage of the prior art
1
. However, the output portion
17
of the governor lever
14
unseparably engages with the fuel meter
21
of the fuel injection pump. This requires setting a resilient force of the return spring
28
of the boost actuator
26
to have such a strength as substantially balancing an extension force of the governor spring
13
at the time of quick acceleration so that the boost actuator
26
can inhibit the fuel meter
21
from moving for fuel increase at the time of the quick acceleration. Correspondingly, a diaphragm
27
must have its pressure receiving area increased. This makes the boost actuator
26
large as a whole as well as in the prior art
1
.
Under the above circumstance, the present invention has been creased. It has an object to secure an ability of starting an engine by a boost actuator having a simple and inexpensive downsized structure without requiring a driving force strong enough to overcome the return spring of the boost actuator for placing the fuel meter at the starting fuel increase position. Further, it has another object to provide a fuel limitation device which inhibits the excessive fuel supply when making the warm start and prevents the generation of black smoke and the wasteful fuel consumption.
The present invention has the same basic structure as the prior art
1
(see FIG.
11
), for example, as shown in
FIGS. 1
,
2
,
8
,
9
and
10
.
A fuel meter
21
of a fuel injection pump for an engine with a supercharger is made movable for fuel metering through a governor lever
14
. A swing lever
31
is supported by a pivot axis (Q) and has a power input point (J) which engages with an output rod
30
of a diaphragm-type boost actuator
26
. The swing lever
31
has a power output point (K) which faces the fuel meter
21
from a fuel increase side (R) of the fuel meter
21
. If the boost actuator
26
operates in response to a delayed rise of a pressure (P) supercharged to the engine (E), the power output point (K) of the swing lever
31
inhibits the fuel meter
21
from moving for fuel increase.
In a fuel limitation device for an engine with a supercharger having the foregoing basic structure, an invention as set forth in claim
1
(a first invention), for example, as shown in
FIGS. 1
,
2
and
8
, connectably and separably opposes an output portion
17
of the governor lever
14
to the fuel meter
21
from a fuel increase side (R) and urges the fuel meter
21
by a start spring
18
toward a starting fuel increase side. An actuator
40
displaces the pivot axis (Q) to position the power output point (K) of the swing lever
31
on the fuel increase side (R) or a fuel decrease side (L). When making
Sakano Tomoyoshi
Tsuji Hidemasa
Yoshii Osamu
Bacon & Thomas PLLC
Kubota Corporation
Nguyen Hoang
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