JPH01178733A - Fuel injection quantity controller for diesel engine with supercharger - Google Patents

Abstract

PURPOSE:To keep off the occurrence of black smoke due to an oversupply fuel at acceleration at the time of full load stationary driving by installing a fuel limiting lever which limits a fuel injection by action of a vacuum actuator provided with a selector valve. CONSTITUTION:When supercharging pressure is less than the setting one, a maximum injection quantity is regulated to a specified rack position by regulation of a fuel limiting lever 41, and thereby an oversupply of fuel is kept back for a while till supercharging pressure goes up. When it becomes more than the setting pressure value, a pressure switch 45 is turned to ON, and a solenoid part 66 is energized with current whereby atmospheric air is led into a vacuum 53 from an intake part 61 by a selector valve 42. With this atmospheric air, a vacuum actuator 40 operates and the fuel limiting valve 41 rotates, so that a governor lever 7 is rotated to the fuel increment side. Since rotation of the fuel limiting lever 41 is gently carried out by action of a throttle valve 62 hereat, the oversupply of fuel is thus preventable even at the time of sudden acceleration. With this constitution, black smoke due to the fuel oversupply is preventable even at the time of sudden acceleration from a low speed range or at the time of acceleration from a relatively high speed range.

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 the January target) In order to achieve the target of "2.1", the present invention regulates the maximum amount of movement toward the fuel increase side for members for increasing and decreasing the fuel injection amount such as the governor lever. The fuel limiting lever is provided with a freely displaceable fuel limiting lever, the fuel limiting lever is interlocked and connected to the output part of the negative pressure actuator, and the fuel limiting lever is displaced 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 popular introduction part via a switching valve, and the atmosphere introduction part is equipped with a throttle valve, and the supercharging pressure is used as a switching input element. A switching device is connected to the switching valve, and when the supercharging pressure is less than a 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.

(Example) First, to explain the construction of a governor for a diesel engine with a supercharger, as shown in FIG. A governor sleeve 6 is supported at the front end of the extending 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
contacts the governor sleeve 6, and as the rotational speed of the camshaft 11 increases, the governor weight 5 expands and pushes the governor sleeve 6 forward.

A governor lever 7, a tension lever 8, and a thrust lever 9 are rotatably supported on the governor lever shaft 17. A fuel increase/decrease rack operating link 20 is pivotally connected to the upper end of the governor lever 7, and the link 20 extends toward the fuel injection pump 1 and is connected to a fuel increase/decrease rack of the fuel injection pump.

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 7a and 7b and a planar connecting portion 7c that integrally connects their lower ends. A lever portion 7a%7b is rotatably supported by a governor lever shaft 17 via a cylindrical metal 15. One governor lever portion 7a extends upwardly and is pivotally connected to the rack operating link 20, and the other governor lever portion 7b connects its upper rear end to the thrust lever 9.
A set spring 25 is tensioned between the front end of the upper end, and the tension of the set spring 25 engages the front end of the upper end of the governor lever part 7b with the protrusion on the front end of the upper end of the thrust lever 9. The 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 coil 5 to rotate the lever. . 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 amount of rotation of the tension lever 8 in the fuel increasing direction to R2 in FIG. 6.

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 limit lever 4, a three-way switching valve (electromagnetic solenoid valve) 42, and a pressure switch 45.

As shown in FIG. 2, the negative pressure actuator 40 is composed of a slider rod 47, an actuator case 48, a case lid 49, a coil spring 51, a rubber diaphragm 52, and the like. These are pre-assembled into one actuator unit, and then fitted and fixed to the two-part mounting portion 3a of the governor case 3. The outer peripheral end of the rubber diaphragm 52 is sandwiched between the actuator case 48 and the case lid 49, and a negative pressure chamber 53 is formed between the case lid 49 and the rubber diaphragm 52. The coil spring 5] is compressed between the center of the rubber diaphragm 52 and the front end of the case lid 59.

The center part of the rubber diaphragm 52 is a slider rod 47
The slider rod 47 is integrally connected to the actuator case 48 and is movable in the front and rear directions and extends rearward. The slider rod 47 is biased rearward by the coil spring 5, and a pair of front and rear clamping plates 54 are screwed onto the rear end of the rod.

The middle part of the fuel limiting lever 4 is rotatably supported by a shaft part 43, and the upper end pin 44 of the fuel limiting lever 1-41 is engaged with the clamping play 1 and 54 of the slider rod 47. . The lower end 41-a of the fuel restriction lever 41 faces the front edge of the Kahana lever 7 so as to be engageable from the front side (fuel increase side).

In FIG. 1, the three-way switching valve 42 has first, second, and third ports 1, 57, 58, and 59, and the first port 57 communicates with the negative pressure chamber 53 of the negative pressure actuator 40, and the second The port 58 communicates with a vacuum pump (negative pressure supply section) 60,
The third bows 1 and 5 communicate with the atmosphere introduction section 6]. A valve shaft 65 having a valve body 65a is provided in the switching valve 42 so as to be freely movable in the axial direction, and by moving the valve shaft 65 in the axial direction, the second port 58 and five third ports are connected to the boat 57. It can be opened and closed freely by switching.

The valve shaft 65 is urged by a spring 68 and is seated at the inlet of the third port 59, and is inserted into the solenoid section 66. That is, when the solenoid part 66 is in a de-energized state, the third port 59 is opened by the elastic force J of the spring 68 as shown in FIG.
is closed, and the second bow 1.58 is opened to the first port 57. On the other hand, in the energized state, the valve stem 65 is protruded to close the second port 58, and the third bow 1.5 is opened to the first port 57. It is designed to open against

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

The solenoid section 66 is connected to the battery 50 via a pressure switch 45, and when the pressure switch 45 is turned on,
When this happens, 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 71 is connected to the rubber diaphragm 70 and is biased toward the pressure chamber 7B by a spring 72. That is, when the supercharging pressure in the pressure chamber 73 reaches the set pressure value P] (for example, 1.00 mmHg) set by the spring 72, the actuating body 73 moves against the spring 72, and both contacts 75
It is configured so that it comes into contact with and turns on.

-9= Also, the temperature switch 100 is connected to each of its terminals or to each terminal of the pressure switch 45, and detects the engine temperature, such as lubricating oil temperature, cooling water temperature, exhaust temperature, or cylinder temperature, and detects the temperature below the set temperature. It stays ON, and turns OFF when the temperature reaches the set temperature. That is, when the temperature is below the set temperature, the limit line (2) in FIG. 6 is maintained, and when the temperature is above the set temperature, the limit line (2) 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, when 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. 6 from the time of starting, thereby achieving fuel savings.

FIG. 6 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. Limit line ■ and R1 are the first
The rack limit position and limit lines I and R2 when negative pressure is supplied to the negative pressure actuator 40 shown in the figure are the rack limit positions when negative pressure is not supplied to the negative pressure actuator 40.

FIG. 7 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. 8 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 4 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 in 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. 6 due to the starting increase spring 28.
As shown in the figure, the amount of fuel 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.
Negative pressure is supplied from the slider rod 47 to the spring 51.
Therefore, the limiting rack position is R1 in FIG. 6.

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 Figure 8 is required, and the required injection amount is small until the rotation speed NJ in the low speed range is low 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 supercharging pressure is less than 21 (equivalent to less than the rotational speed N1), the maximum injection amount is regulated to the limit rack position R1 in Fig. 6 by the regulation of the fuel limit lever 41 in Fig. 1, thereby preventing excess fuel. and prevent black smoke from occurring.

When the boost pressure exceeds P1, pressure switch 4 in Figure 1 is activated.
5 is turned ON, the solenoid part 66 is energized, the third boat 59 opens with respect to the first boat 57, and the second port 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 air is introduced from the air introduction section 61, the air is introduced gently by the action of the throttle section 62.

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

As shown by the broken line in FIG. 7, the supercharging delay becomes noticeable, but 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. 9 shows the relationship between engine speed and shaft torque, and the thin solid line shows the constant boost pressure line. That is, in the diagonally shaded range divided by the equal boost pressure line corresponding to the boost pressure P1, the fuel injection amount is limited to R1, and when accelerating from within this range, the restriction is gradually changed from R1 due to the action of the throttle valve 62. Since the process shifts 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.

(Another Embodiment) FIG. 4 shows an example in which a normally closed safety switch 79 is provided in the wiring section between the solenoid section 66 and the pressure switch 45. This safety switch 79 has a rubber diaphragm 80 and an actuating body 8]
, a spring 82, and a pressure chamber 83, and the pressure chamber 83 is connected to a supercharger 75 to be supplied with supercharged air. The actuating body 81 is connected to the rubber diaphragm 80 and is biased toward the contact 85 by a spring 82 so that both contacts 85
is in contact with. That is, the supercharging pressure in the pressure chamber 83
When the set pressure value P2 (greater than PI) by 2 is reached, the actuating body 8 moves against the spring 82, and both contacts 8
It is configured to be in the OFF state away from 5.

That is, if the supply air pressure becomes too high and exceeds 12 due to a failure of the Uniist Gate 1 (supply pressure regulating valve), the safety switch 79 is turned OFF, the solenoid section 66 is brought into an emergency energized state, and the negative pressure actuator 40 is turned off. , and limits the fuel injection amount to R1.

This prevents the maximum internal pressure of the cylinder from becoming excessive and prevents damage to the cylinder.

(2) FIG. 5 shows an example in which a pressure switch 89 is directly connected to the switching valve 42 as a switching device. That is, pressure switch 8
One is the rubber diaphragm 90, the push rod 91, and the spring 9.
2 and a pressure chamber 93, and the pressure chamber 93 is connected to a supercharger 75 to be supplied with supercharged air. The push rod 91 is connected to the rubber diaphragm 90, and
It is urged by a spring 92 in a direction away from the valve body portion 65a. That is, when the supercharging pressure in the pressure chamber 93 exceeds the pressure value PL set by the spring 92 (for example, 100 mm 1 g), the rod 93 moves against the spring 92, pushes the valve body 65a, and opens the first port 57. 3rd port 59
At the same time as opening, the second port 58 is closed, and the atmosphere is supplied to the negative pressure actuator 40.

(Effects of the Invention) As explained above, according to the present invention: (1) When the supercharging pressure is less than the set pressure value, the limit lever 41 limits the fuel injection amount to the side of the set pressure value to prevent excess fuel, and When the pressure exceeds the pressure value, the restriction lever 41 is gently returned to the fuel increase side through the action of the throttle valve 62, so that it is possible to At any time of acceleration from a high-speed rotation range, excess fuel during the period of insufficient supercharging can be sufficiently prevented, and generation of black smoke during acceleration can be prevented.

(2) Since there is no need to incorporate, for example, a reverse Angleich spring into the governor link mechanism, assembly of the governor does not become 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, Figures 4 and 5 are schematic cross-sectional views of different embodiments, and Figure 6 is the pump rotation speed and limit rack. Figure 7 is a graph showing the relationship between positions, Figure 7 is a graph showing changes in boost pressure, Figure 8 is a graph showing the required injection amount during full load steady operation, and Figure 9 is a graph showing the relationship between engine speed and shaft torque. This is a graph showing. 40...Negative pressure actuator, 41...Fuel restriction lever, 42...3-way switching valve, 60...Vacuum pump (negative pressure supply section), 61...Popular introduction section,
45.66, ... Pressure switch, solenoid part (an example of a switching device), 90... Pressure switch (another example of a switching device) Patent applicant Yanmar Diesel Co., Ltd. --1-Co procedure amendment writing method) March 31, 1988 Patent Application No. 33b592 No. 2, Name of invention Fuel injection amount limiting device for diesel engine with supercharger 3, Case of person making amendment Relationship with Patent Applicant Address: 1-32 Chayamachi, Kita-ku, Osaka Name (678) Yanmar Diesel Co., Ltd. Representative Director: Atsushi Yamaoka 4, Agent Address: 2-9 Higashitenma, Kita-ku, Osaka No. 4 @ 7th floor, Chiyoda Building East Building (@ 530) 5. Date of amendment order (shipment date) March 29, 1988
Day 6, subject of amendment Drawing 7, content of amendment No change to the content of the drawing). 8. List of attached documents 1 engraving drawing 1 copy
14. ' Procedural amendment (voluntary) April 1, 1988 Patent Application No. 335592 2, Name of invention Fuel injection amount limiting device for supercharged diesel engine 3, Relationship with the person making the amendment case Patent applicant address: 1-32 Chayamachi, Kita-ku, Osaka City Name (678) Yanmar Diesel Co., Ltd. Representative Director: Atsushi Yamaoka 4, Agent address: 2-9-4 Higashitenma, Kita-ku, Osaka City Chiyoda Building East Building 7th Floor (・530) Telephone Osaka (06) 353-1635, Trade'1 Labor 〒9--・'j Name (6525) Patent Attorney Tadaka Taishoku (・□
, 15. Date of amendment order (shipment date) Month, Showa
[16. Target of amendment Drawing □□ (1) Figure 6 of the drawings will be amended as shown in the attached drawing. This is a correction to the line ■ in the tatami diagram. 8. Inventory drawing of attached documents (Figure 6) One or more copies of pump surface softness (rρm)

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. A switching device that uses boost pressure as an input element for switching is connected to the switching valve, and when the boost pressure is less than the set pressure value, the switching valve is connected to the negative pressure supply section. 1. A fuel injection amount control device for a diesel engine with a supercharger, characterized in that when the pressure is higher than a set pressure value, the fuel injection amount is switched to the atmosphere inlet side.