JP3878822B2 - Fuel metering device for diesel engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel metering device for a diesel engine.
[0002]
[Premise Technology]
The present invention has the following basic configuration.
As shown in FIGS. 1 to 3, a slider (5) is slidably provided in the swinging direction (4) of the governor lever (2a) in the swinging direction. The swinging end (4) and the slider (5 The pin insertion gap (6) is provided between the rack pin (3a) of the fuel injection pump (1) and the pin insertion gap (6) is inserted into the slider (5). A spring (S) for biasing pressure (biasing in the direction of narrowing) is provided, and the rack pin (3a) is adjusted by the governor lever (2a).
[0003]
[Prior art]
2. Description of the Related Art Conventionally, as a fuel metering device for a diesel engine, in the above basic configuration, a rack pin of a fuel injection pump inserted into a pin insertion gap is sandwiched by a narrow pressure biasing force of a spring.
[0004]
[Problems to be solved by the invention]
The above prior art has the following problems.
By swinging the governor lever, the outer peripheral surface of the rack pin and the opposing surface of the pin insertion gap are rubbed against each other while receiving contact pressure due to the spring force, and these wear gradually. In this case, the metering rack of the fuel injection pump gradually shifts to the fuel increase side, and the fuel injection amount becomes excessive. This is a factor that decreases the fuel metering accuracy and increases the concentration of harmful components in the exhaust gas.
[0005]
Therefore, prior to the present invention, the one shown in FIG. 4 was proposed (Japanese Patent Application No. 2000-327992: hereinafter referred to as “prior proposal example”).
As shown in FIG. 4, in the fuel metering device for a diesel engine having the above basic configuration, the previously proposed example is provided with a U-shaped contact piece (20) integrally at the tip in the sliding direction of the slider (5). The U-shaped contact piece (20) faces the high idle spring (19), the rear end face (5a) of the U-shaped contact piece (20) and the front end face of the swing end (4). The pin insertion gap (6) is formed between the pin insertion gap (4a), and the dimension (L ₁ ) of the pin insertion gap (6) is defined below the front end face (4a) of the swing end (4). And a stopper contact portion (8) is provided below the rear end surface (5a) of the U-shaped contact piece (20), and the stopper (7) is provided as a stopper contact portion. (8) in the state where brought into contact, the dimensions of the pin insertion gap (6) (L ₁₎ is obtained by construction to be larger than the outer diameter (L ₂₎ of Rakkupin (3a) That.
[0006]
However, the prior proposal example has the following problems.
The stopper contact portion (8) of the U-shaped contact piece (20) of the slider 5 becomes an arc shape by bending. On the other hand, the contact portion of the stopper (7) of the governor lever (2a) becomes a small arc shape by punching. Therefore, when the slider (5) is slidably assembled to the swing end (4) of the governor lever (2a), the contact position of the stopper (7) with respect to the stopper contact section (8) is slightly shifted. For this reason, the dimension (L ₁ ) of the pin insertion gap (6) is greatly displaced beyond the assembly error.
[0007]
The present invention takes such circumstances into consideration, and its purpose is to prevent the displacement of the pin insertion gap from exceeding a mounting error and to minimize wear of the rack pin and the pin insertion gap. Another object of the present invention is to provide a fuel metering device for a diesel engine that can improve fuel metering accuracy.
[0008]
[Means for Solving the Problems]
For example, as shown in FIG. 1, the present invention provides a fuel metering device for a diesel engine having the above-described basic configuration, and a U-shaped contact piece (20) is integrally provided at the sliding direction tip of the slider (5). The U-shaped contact piece (20) faces the high idle spring (19), the rear end face (5a) of the U-shaped contact piece (20) and the front end face of the swing end (4). The pin insertion gap (6) is formed between the pin insertion gap (4a), and the dimension (L ₁ ) of the pin insertion gap (6) is defined below the front end face (4a) of the swing end (4). And a stopper abutting portion that projects downward from the lower end (5a) of the U-shaped contact piece (20) below the U-shaped lower edge (20a). 8) is extended, and when the stopper (7) is in contact with the stopper contact portion (8), the dimension (L ₁ ) of the pin insertion gap (6) is It is characterized by being configured to be larger than the outer diameter (L ₂ ) of the cuppin (3a).
[0009]
[Action and effect of the invention]
The present invention has the following actions and effects.
(A) A stopper (7) for defining the dimension (L1) of the pin insertion gap (6) is provided below the front end surface (4a) of the swing end (4) of the governor lever (2a), and the slider (5) Since the stopper contact portion (8) projecting downward from the U-shaped lower edge (20a) is extended from the lower part of the rear end surface (5a) of the U-shaped contact piece (20), the stopper Even if the contact portion of the stopper (7) with respect to the contact portion (8) is slightly displaced, the dimension (L ₁ ) of the pin insertion gap (6) does not cause a large displacement greater than the assembly error. This improves the fuel metering accuracy.
[0010]
(B) When the stopper (7) is in contact with the stopper contact portion (8), the dimension (L ₁ ) of the pin insertion gap (6) is larger than the outer diameter (L ₂ ) of the rack pin (3a). Thus, as in the previously proposed example, even if the governor lever (2a) swings, the outer peripheral surface of the rack pin (3a) is either of the opposing surfaces (5a) (4a) of the pin insertion gap (6). Only one of these surfaces rubs against each other, and contact pressure due to the spring force (Sa) is not applied to the rubbed surfaces, so that wear due to this is prevented. When this wear occurs, the fuel metering rack (3) gradually shifts to the fuel increase side and the fuel injection amount becomes excessive. However, since this problem does not occur, the fuel metering accuracy is improved and the exhaust gas is increased. Increases in the concentration of harmful components in it are also suppressed.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a rear view of a main part of a fuel metering device according to the present invention (a view of a rocking end of a first governor lever and a slider viewed from the fuel injection pump side), and FIG. 2 is a diagram of a diesel engine according to the present invention. FIG. 3 is a longitudinal sectional side view of the fuel metering device, and FIG. 3 is a longitudinal side view of the fuel metering device. This embodiment is a fuel metering device applied to a vertical multi-cylinder diesel engine.
[0012]
As shown in FIGS. 2 and 3, the fuel metering device includes a fuel injection pump (1) and a mechanical governor (2). These are all housed in the pump housing case (10). The fuel injection pump (1) includes a fuel metering rack (3). The fuel metering rack (3) includes a rack pin (3a) and is slidably attached in the fuel increasing / decreasing direction. In the fuel metering rack (3), the output portion (18a) of the engine stop solenoid (18) faces the end portion on the fuel increase side.
[0013]
The mechanical governor (2) includes a first governor lever (2a), a second governor lever (2b), and a third governor lever (2c). These governor levers (2a), (2b) and (2c) are all pivotally supported by the governor lever shaft (9). The governor lever shaft (9) is installed in the pump housing case (10). The first governor lever (2a) is provided with a governor force input portion (13) at the lower oscillating end thereof, which faces the governor sleeve (21), and this governor sleeve (21) faces the governor weight (14). It is out.
[0014]
The second governor lever (2b) faces the first governor lever (2b) from the fuel reduction side, and is linked to the governing lever (17) via the governor spring (16). The second governor lever (2b) is provided with a contact portion (11) at the upper oscillating end thereof, and this is exposed to the fuel limit bolt (12) from the fuel reduction side. The third governor lever (2c) is disposed between the first governor lever (2a) and the second governor lever (2b), and includes a torque riser (15) at the upper swing end thereof. A torque rise spring (not shown) is accommodated in the torque rise device (15). Although not shown, a torque rise limiting bolt faces the third governor lever (2c) from the fuel increase side, and is attached so as to be able to advance and retract from the outside of the pump housing case (10).
[0015]
As shown in FIG. 1, the first governor lever (2a) is provided with a slider (5) at the upper swing end (4), and this slider (5) is swung in the first governor lever (2a). It is slidably mounted in the [Fuel increase (R) decrease (L) direction]. A U-shaped contact piece (20) that can come into contact with the high idle spring (19) is integrally provided at the end of the slider (5) in the sliding direction, and this U-shaped contact piece (20). A pin insertion gap (6) is formed between the rear end face (5a) of the first end and the front end face (4a) of the swinging end (4), and the fuel injection pump (1) is inserted into the pin insertion gap (6). A rack pin (3a) is inserted. The slider (5) is provided with a spring (S) for biasing the pin insertion gap (6) with a narrow pressure (biasing it in the narrowing direction). The spring (S) also has a function as a start spring that urges the first governor lever (2a) to the start increasing position.
[0016]
The function of the mechanical governor (2) is as follows.
During engine operation, the governor levers (2a), (2b) and (2c) swing together as a result of the unbalanced force of the governor spring force (16a), governor force (14a) and bias spring force (Sa). The fuel metering rack (3) is metered and moved. When the engine load exceeds the rated load, the second governor lever (2b) is received by the fuel limiting bolt (12), and the governor force (14a), bias spring force (Sa), and torque rise spring force (not shown) The unbalanced force causes the first governor lever (2a) and the third governor lever (2c) to swing together to move the fuel metering rack (3) by metering, and suppresses engine stall by torque rise. The maximum fuel injection amount of the torque rise can be adjusted from the outside of the injection pump housing case (10) by a torque rise limiting bolt.
[0017]
When the engine is stopped, the fuel metering rack (3) is pushed to the fuel reduction side by the engine stop solenoid (18). In this case, since the fuel metering rack (3) can move to the fuel non-injection position while pushing the slider (5) with the rack pin (3a), the fuel metering rack (3) has a resistance of the governor spring force (16a). However, only a resistance of a spring force (Sa) smaller than the governor spring force (16a) is applied. For this reason, the engine stop solenoid (18) may be a small and small output. Since no governor force (14a) is generated when the engine is started, the fuel metering rack (3) is pulled to the fuel increase side together with the first governor lever (2a) by the spring force (Sa), and torque rise The starting position is increased beyond the limit position, and the starting performance is improved.
[0018]
In this embodiment, the following device is made.
A stopper (7) for defining the dimension (L1) of the pin insertion gap (6) is projected from the lower end of the front end face (4a) of the swing end (4) of the first governor lever (2a).
On the other hand, a stopper contact portion (8) is extended from the lower part of the rear end surface (5a) of the U-shaped contact piece (20) of the slider (5). The stopper contact portion (8) is an extension of the rear end surface (5a) downward, and projects downward from the U-shaped lower edge (20a) of the U-shaped contact piece (20). As a result, even if the contact position of the stopper (7) with respect to the stopper contact portion (8) is slightly shifted, the dimension (L ₁ ) of the pin insertion gap (6) may be greatly shifted beyond the assembly error. There is no. This improves the fuel metering accuracy.
[0019]
Further, when the stopper (7) is in contact with the stopper abutting portion (8), the dimension (L ₁ ) of the pin insertion gap (6) is larger than the outer diameter (L ₂ ) of the rack pin (3a). It is configured. Thereby, even if the first governor lever (2a) swings, the outer peripheral surface of the rack pin (3a) rubs only one of the opposing surfaces (5a) and (4a) forming the pin insertion gap (6). In addition, since the contact surface due to the spring force (Sa) is not applied to the rubbing surfaces, wear caused by this is prevented. As a result, the fuel metering accuracy is greatly improved, and an increase in the concentration of harmful components in the exhaust gas is also suppressed.
[0020]
In addition, this invention is not limited to said each embodiment, For example, it can add and implement suitably as follows.
(1) In the above embodiment, the spring S is exemplified as having a function as a start spring that biases the first governor lever (2a) to the start increasing position. For example, the spring may be constructed between the swing end (4) of the first governor lever (2a) and the slider (5).
(2) The mechanical governor may be a two-lever type without the third governor lever (2c).
[Brief description of the drawings]
FIG. 1 is a rear view of a main part of a fuel metering device according to a first embodiment of the present invention (a view of a rocking end of a first governor lever and a slider as viewed from the fuel injection pump side).
FIG. 2 is a longitudinal front view of a fuel metering device for a diesel engine according to an embodiment of the present invention.
FIG. 3 is a longitudinal side view of the fuel metering device.
FIG. 4 is a view corresponding to FIG. 1 of a conventional fuel metering device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Fuel injection pump, 2a ... 1st governor lever, 3a ... Rack pin, 4 ... Swing end part of 1st governor lever, 4a ... Front end surface of rocking | fluctuation end part, 5 ... Slider, 5a ... U-shaped contact piece Rear end face, 6 ... pin insertion gap, 7 ... stopper, 8 ... stopper contact part, 19 ... high idle spring, 20 ... U-shaped contact piece, S ... spring, L1 ... dimension of pin insertion gap, L2 ... rack pin Outside diameter.

Claims (1)

A slider (5) is slidably provided in the swinging direction (4) of the governor lever (2a) in the swinging direction, and a pin insertion gap (6) is provided between the swinging end (4) and the slider (5). ), And the rack pin (3a) of the fuel injection pump (1) is inserted into the pin insertion gap (6), and a spring (S) for biasing the pin insertion gap (6) to the slider (5) is applied to the slider (5). A fuel metering device for a diesel engine configured to meter and move the rack pin (3a) with the governor lever (2a);
A U-shaped contact piece (20) is integrally provided at the end of the slider (5) in the sliding direction, and the U-shaped contact piece (20) faces the high idle spring (19).
The pin insertion gap (6) is formed between the rear end surface (5a) of the U-shaped contact piece (20) and the front end surface (4a) of the swing end portion (4),
A stopper (7) for defining the dimension (L ₁ ) of the pin insertion gap (6) protrudes from the lower end (4a) of the rocking end (4), and the U-shaped contact piece. A stopper contact portion (8) projecting downward from the U-shaped lower edge (20a) from the lower portion of the rear end face (5a) of (20),
When the stopper (7) is in contact with the stopper contact portion (8), the dimension (L ₁ ) of the pin insertion gap (6) is larger than the outer diameter (L ₂ ) of the rack pin (3a). A fuel metering device for a diesel engine, characterized by comprising:

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