JPH01290928A - Device for controlling fuel injection quantity of diesel engine with supercharger - Google Patents

Abstract

PURPOSE:To prevent the generation of black smoke at the time of acceleration by switchingly operating a negative-pressure actuator which is interlockedly linked to a fuel limit lever in accordance with a supercharging pressure and engine speed. CONSTITUTION:A vacuum pump 60 and an air introducing portion 61 are connected to a negative-pressure actuator 40 which is interlockedly linked to a fuel limit lever 41, via a selector valve 42. When a supercharging pressure is less than a set value, a negative pressure is fed to bring the lever 41 to a fuel decrease side. When the rotating speed is less than a set value, the negative pressure is fed irrespective of the supercharging pressure. When the supercharging pressure or rotating speed gets above the set value, the lever 41 is gently returned to a fuel increase side by the action of a throttle valve 62 provided on the air introducing portion 61. Thereby, the generation of black smoke at the time of accelerating can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fuel injection amount control device for a supercharged diesel engine.

(Prior art and its problems) When accelerating an engine equipped with a supercharger, the pressure rise by the supercharger turbine lags with respect to the increase in rotational speed, that is, there is a delay in supercharging, resulting in a shortage of fuel air. This causes excess fuel to be supplied during acceleration, causing black smoke to be generated.

Also, during continuous full-load operation or gradual acceleration under full load, the boost pressure is low in the low-speed rotation range, so black smoke will be generated unless the fuel supply amount is reduced.

For example, there is a structure in which a reverse Angleich spring is built into the governor link mechanism to prevent the generation of black smoke, but the governor link mechanism itself becomes a complicated link mechanism, and it takes time and effort to assemble the governor. For example, if it is possible to prevent black smoke during gradual acceleration during full-load steady operation, when there is a noticeable supercharging delay such as during sudden acceleration, an excess fuel condition will occur in the first half of the acceleration process and black smoke will be generated. There are things to do.

(Purpose of the Invention) The present invention provides the following advantages: The purpose is to surely prevent the generation of black smoke due to excess fuel.

(Technical Means for Achieving +1 Objective) In order to achieve the above objective, the present invention provides a freely displaceable fuel that regulates the maximum amount of movement toward the fuel increase side with respect to a fuel injection amount increase/decrease member such as a governor lever. comprising a restriction lever, the fuel restriction lever is operatively connected to the output portion of the negative pressure actuator, and configured to displace the fuel restriction lever to the fuel reduction side by supplying negative pressure to the negative pressure chamber of the negative pressure actuator; The negative pressure chamber is switchably connected to the negative pressure supply part and the atmosphere introduction part via the switching valve I2, and the atmosphere introduction part is equipped with a throttle valve to switch between a specific boost pressure and a specific engine speed. A switching device as an input element for λ is connected to the switching valve 7, so that when the boost pressure is less than the set pressure value, the switching valve is switched to the negative pressure supply part side, and when it is higher than the set pressure value, it is switched to the atmosphere introduction part side. Also, when the engine speed is less than a set value, the switching valve is switched to the negative pressure supply section side regardless of the boost pressure.

(Example) First, to explain the governor structure of a diesel engine with a supercharger, in FIG.
1 extends, and a governor sleeve 6 is supported at the front end of the camshaft 11 so as to be freely movable in the axial direction, and a governor weight 5 is supported so as to be freely expandable. Governor weight 5 comes into contact with the governor sleeve 6, and as the rotational speed of the camshaft 11 increases, the governor weight 5 expands and the governor sleeve 6
It is designed to push forward.

The governor lever shaft 17 includes the governor lever 7 and the tensicon 1.
- The collar 8 and the thrust lever 9 are rotatably supported. A fuel increase/decrease rack operating link 20 is pivotally connected to the upper end of the governor lever 7, and the link 20 is sharpened toward the fuel injection pump 1 side and connected to the fuel increase/decrease rack of the fuel injection pump 1. There is.

The tension lever 8 is formed into an inverted rLJ shape, and a governor spring 10 is stretched between its rear upper end and the front end of the accelerator control lever 22, and the governor spring 10 moves the tension lever 8 to the fuel increasing side. It is biased towards. The control lever 22 is rotatably supported by the governor case 3 via a control shaft 24 and is connected to an accelerator device (not shown) such as an accelerator pedal.

In FIG. 3 showing an exploded perspective view of the governor, the governor lever 7 is formed in a U-shape by a pair of left and right lever portions 7a17b and a planar connecting portion 7c that integrally connects their lower ends. 7a and 7b are cylinder metal 1
It is rotatably supported on the governor lever shaft] 7 via the governor lever shaft 5. One governor lever portion 7a extends upward and is pivotally connected to the rack operating link 20, and the other governor lever portion 7b has a set spring 25 tensioned between its upper rear end and the upper front end of the thrust lever 9. The upper front end of the governor lever portion 7b is engaged with the projection on the upper front end of the thrust lever 9 by the tensile force of the set spring 25.

The thrust lever 9 is also formed in an upward U-shape from a pair of left and right lever portions and a connecting portion 9a that integrally connects their lower ends, and is supported by the governor lever shaft 17 via the cylindrical metal 15. There is. The lower end connecting portion 9a of the thrust lever 9 is provided with a shifter 26 and receives governor force.

A starting increase spring 28 is compressed between the lower end of the tension lever 8 and the connecting portion 9a of the thrust lever 9.

Reference numeral 31 in FIG. 2 is a fuel limiter, which limits the maximum simultaneous movement of the tension lever 8 in the fuel increasing direction to R2 in FIG. 4.

A fuel injection amount control device according to the present invention is connected to the governor as described above. As shown in FIG. 1, the fuel injection amount control device includes a negative pressure actuator 40, a fuel restriction lever 41, a three-way switching valve (electromagnetic solenoid section) 42, and a pressure switch 45.

As shown in FIG. 2, the negative pressure actuator 40 includes a slider rod 47, an actuator case 48, a case lid 49,
It is composed of a coil spring 51, a rubber diaphragm 52, and the like. These are preassembled as one actuator unit, and then fitted and fixed to the upper mounting portions 3a of the governor case 3. The outer peripheral end of the rubber diaphragm 52 is held between the actuator case 48 and the case lid 49, and a negative and positive chamber 53 is formed between the case M49 and the rubber diaphragm 52. The coil spring 51 is compressed between the center of the rubber diaphragm 52 and the front end surfaces of the five case lids.

The center part of the rubber diaphragm 52 is a slider rod 47
The slider port 47 is movable in the front and rear directions of the actuator case 48 and extends rearward. The slider rod 47 is biased rearward (=1) by the coil spring 51, and a pair of front and rear clamping plates 54 are screwed onto the rear end of the rod.

The fuel restriction lever 41 is rotatably supported by a shaft portion 43 at its middle portion, and the fuel restriction lever 41 has an upper end bin 4 .
4 is engaged with the clamping plate 54 of the slider rod 47. The lower end 41a of the fuel restriction lever 41 faces the front edge of the governor lever 7 so as to be engageable from the front side (fuel increase side).

In FIG. 1, the three-way switching valve 42 includes first, second, and third ports 57, 58, and 59, the first boat 57 communicates with the negative pressure chamber 53 of the negative pressure actuator 40, and the second boat 5
8 communicates with a vacuum pump (negative pressure supply section) 60;
The third boat 59 communicates with the atmosphere introduction section 61. A valve shaft 65 having a valve body 65a is provided within the switching valve 42 so as to be movable in the axial direction.
A second boat 58 and a third boat 59 can be freely switched to open and close relative to the boat 57.

The valve shaft 65 is urged by a spring 68 and is seated at the inlet of the third boat 59, and is inserted into the solenoid section 66. That is, when the solenoid part 66 is in a non-energized state, the third boat 59 is closed by the elastic force of the spring 68 as shown in FIG. 1, and the second boat 58 is opened with respect to the first boat 57.
On the other hand, when energized, the valve stem 65 is projected to close the second boat 58 and open the third boat 59 relative to the first boat 57.

A throttle valve 62 is arranged in the air introduction section 61 .

The solenoid section 66 is connected to the battery 50 via the pressure switch 45 and the rotary switch 99, and when the pressure switch 45 and the nine rotary switches are turned on, the solenoid section 66 is energized.

The pressure switch 45 includes a rubber diaphragm 70 and an actuating body 7.
1, a spring 72, and a pressure chamber 73, and the pressure chamber 73 is connected to a supercharger 75 to be supplied with supercharged air. The actuating body 7] is connected to a rubber diaphragm 70 and urged toward the pressure chamber 73 by a spring 72.

In other words, when the supercharging pressure in the pressure chamber 73 exceeds the pressure value P set by the spring 72 (for example, 100 mmmm1l), the actuating body 73 moves against the spring 72 and comes into contact with both contacts 75, turning on. It is configured as follows.

The rotation switch 99 is connected to a rotation pickup 101, and the rotation pickup 101- is arranged on a rotating body of the engine, such as a crank gear 102, detects the engine rotation speed, and issues a rotation speed signal to the nine rotation switches. It has a function. Further, the rotary switch 99 has a function of keeping OFF while the rotational speed signal from the rotational pickup 101 is less than a predetermined rotational speed Nl (for example, 1800 rpm+), and switching to ON when the rotational speed exceeds the predetermined rotational speed N1. .

Further, each terminal of the temperature switch 100 is connected to the battery 5.
0 and the terminal of the switching valve 42, it detects the engine temperature, such as lubricating oil temperature, cooling water temperature, exhaust temperature, or cylinder temperature, and remains ON when the temperature is lower than the set temperature, and turns OFF when the temperature is higher than the set temperature. It is set to switch. That is, when the temperature is lower than the set temperature, the limit line I in FIG. 4 is maintained, and when the temperature is higher than the set temperature, the limit line ■ is maintained.

Therefore, during a cold start in a state where the temperature is lower than the set temperature, the solenoid section 66 is energized to ensure an increase in starting power, and good starting performance can be maintained.

On the other hand, if the engine temperature is higher than the set temperature even at the time of starting and there is no need to increase the amount at start, the rack restriction position is limited to R1 in FIG. 4 from the time of starting, thereby achieving fuel savings.

FIG. 4 is a graph showing changes in the limit rack position with respect to the pump rotation speed, where NO indicates the idling rotation speed and N2 indicates the rated rotation speed. The limit line ■ and R1 are the first
The rack restriction position, restriction line E, and R2 shown in the figure when negative pressure is supplied to the negative pressure actuator 40 are the rack restriction positions when negative pressure is not supplied to the negative pressure actuator 40.

FIG. 5 shows the change in supercharging pressure with respect to the engine speed, where the solid line graph shows the change during full load steady operation, and the broken line shows the change during sudden acceleration.

FIG. 6 shows the change in the required injection amount with respect to the pump rotation speed. The thick solid line shows the required injection amount during full-load steady operation, the thin solid line shows the equal rack diagram, and R1 is the first
The limit rack diagram when the limit lever 41 shown in the figure is rotated by the maximum amount to the fuel reduction side, and R2 shows the limit rack diagram limited by the fuel limiter 31 of FIG.

Explain the operation. Before starting the engine in a cold state, the temperature switch 100 shown in FIG. 1 is in the ON state, so the negative pressure actuator 40 is released as shown in FIG. The rotation speed is 0 as shown in Fig. 4 due to the starting increase spring 28.
0, the amount of fuel increased at startup is ensured.

When the aircraft warms up after starting, the temperature switch 100 in FIG.
is off and the idling speed is NO as shown in FIG. 4, the vacuum pump 60 is in the negative pressure chamber 53 of FIG.
Negative pressure is supplied from the slider rod 47 to the spring 51.
Therefore, the limiting rack position is R1 in FIG. 4.

A case will be described in which, for example, from a rack position of RO at an idling rotational speed NO, the accelerator is gently depressed to gradually accelerate in full-load steady operation or to perform full-load continuous operation.

In this case, the fuel injection amount as shown by the thick solid line in Fig. 6 is required, and the required injection amount is small until around the rotation speed Nl in the low speed range because the boost pressure is low, and when the rotation speed exceeds N1, the required injection amount is small. The amount of injection is also increasing.

That is, when the rotation speed is less than N1, the maximum injection amount in FIG. 4 is regulated to the limit rack position R1 by the regulation of the fuel limit lever 4j in FIG. 1, thereby preventing excess fuel and preventing the generation of black smoke. .

When the number of rotations exceeds N1, the rotation switch 99 in FIG.
is turned ON, the solenoid section 66 is energized, the third boat 59 opens with respect to the first boat 57, and the second boat 58 closes. As a result, the atmosphere is introduced from the atmosphere introduction part 61 into the negative pressure chamber 53, the slider rod 47 is moved rearward by the spring 51, and the fuel restriction lever 41 is rotated to the fuel increase side.

That is, the governor lever 7 is allowed to move toward the fuel increasing side, and the governor lever 7 rotates toward the fuel increasing side. This rotation is limited to the limit rack position R2 by the action of the fuel limiter 31 shown in FIG.

In this state, the supercharging pressure has increased sufficiently, so that sufficient supercharging pressure and corresponding sufficient fuel are secured.

Further, when the atmosphere is introduced from the air introduction section 61, the air is introduced gently by the action of the aperture section 62.

Next, a case will be described in which sudden acceleration is achieved by suddenly stepping on the accelerator from the idle rotation speed NO shown in FIG.

As shown by the broken line in FIG. 5, the supercharging delay becomes noticeable, but even if the rotational speed exceeds N1, the rack position is limited to R1 until the supercharging pressure reaches Pl. When Pl is reached, the pressure switch 45 turns ON and the fuel limit lever 41 begins to rotate in the direction of increasing fuel, but since it rotates slowly due to the throttle valve 62, the injection amount does not increase immediately, but just reaches the supercharging pressure. Since the throttle valve 62 is adjusted so that the amount increases as the amount of fuel increases, black smoke will not be generated due to excess fuel.

FIG. 7 shows the relationship between engine speed and shaft torque, and the thin solid line shows the constant boost pressure line17. That is, in the diagonally shaded range divided by the equal boost pressure line corresponding to the boost pressure Pl and the engine speed N1 output, the fuel injection amount is limited to R1, and when accelerating from within this range, due to the action of the throttle valve 62. Since the restriction gradually shifts from R1 to R2, no black smoke is generated. Also, outside this range, the boost pressure is high, so even if the engine suddenly accelerates, little black smoke will be generated.

(Effects of the Invention) As explained above, according to the present invention: (1) When the boost pressure or engine speed is less than the set value, the limit lever 41 limits the fuel injection amount to the side of the range to prevent excess fuel. When the limit value exceeds the set value, the limit lever 41 is gently returned to the fuel increasing side through the action of the throttle valve 62, so that during steady full-load operation in the full rotation range, it is possible to reduce the During both rapid acceleration and acceleration from a low-speed, high-load range, excess fuel in the engine when undersupercharging can be sufficiently prevented, and generation of black smoke can be prevented.

By the way, during sudden acceleration, depending on the load conditions before acceleration, there may be a lack of air volume during acceleration even when the rotation speed is above the set value, but in this case, the fuel is controlled by the boost pressure to prevent the generation of black smoke. do. For example, it is a point like point S1 in FIG.

- When lowering the rotation speed under full load conditions, the amount of air may be insufficient even when the boost pressure is above the set value, but in this case, the fuel is controlled according to the rotation speed to prevent the generation of black smoke. For example, it is a point like point S2 in FIG.

(2) Since there is no need to incorporate, for example, a reverse angle spring into the governor link mechanism, assembly of the governor is not complicated.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a fuel injection amount control device according to the present invention;
Figure 2 is an enlarged vertical cross-sectional view of the governor section, Figure 3 is an exploded perspective view of the governor, Figure 4 is a graph showing the relationship between pump rotation speed and limit rack position, and Figure 5 shows changes in boost pressure. FIG. 6 is a graph showing the required injection amount during full-load steady operation, and FIG. 7 is a graph showing the relationship between engine speed and shaft torque. 40...Negative pressure actuator, 41...Fuel restriction lever, 42...3-way switching valve, 60...Vacuum pump (negative pressure supply part), 61...Atmospheric introduction part, 45.6
6....Pressure switch, solenoid part, 99...Rotary switch Patent applicant: Yanmar Diesel Co., Ltd. Agent, Patent attorney: Tadataka Omori, ゛. +1 (-

Claims (1)

[Claims] A freely displaceable fuel limiting lever is provided to regulate the maximum amount of movement toward the fuel increasing side with respect to a fuel injection amount increasing/decreasing member such as a governor lever. The fuel restriction lever is configured to be displaced to the fuel reduction side by supplying negative pressure to the negative pressure chamber of the pressure actuator, and the negative pressure chamber can be freely switched between a negative pressure supply section and an atmosphere introduction section via a switching valve. The air inlet is equipped with a throttle valve, and a switching device that uses a specific boost pressure and specific engine speed as input elements for switching is connected to the switching valve, and when the boost pressure is less than the set pressure value, At times, the switching valve is switched to the negative pressure supply side, and when the pressure is higher than the set pressure value, it is switched to the atmosphere introduction part.When the engine speed is less than the set value, the switching valve is switched to the negative pressure supply side, regardless of boost pressure. A fuel injection amount control device for a diesel engine with a supercharger, characterized in that the fuel injection amount control device is configured to switch to a supercharged diesel engine.