JPH0212281Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a distribution type fuel injection pump for an injection-type internal combustion engine such as a diesel engine, and in particular utilizes a temperature-sensitive actuating member made of a known shape memory alloy to increase the amount of fuel injected during cold starting. The present invention relates to a temperature compensated distribution type fuel injection pump that performs temperature compensation for both an increase in fuel injection amount when the fuel temperature rises and an increase in fuel injection amount when the fuel temperature rises.

Generally, in a distribution type fuel injection pump for a diesel engine, etc., when the engine is started, the control sleeve is moved to the starting amount increase position by the action of the start lever and start spring, and the injection amount is increased at the time of starting, and the engine starts. It's becoming easier to do. However, with this mechanism, the starting power increase is still insufficient for starting at low temperatures.
The engine is not running well. Furthermore, when starting at room temperature, there is a problem in that the starting amount increases too much and smoke is likely to occur. To solve this problem, a temperature-sensitive actuating member made of bimetal is provided in the governor sleeve part (for example, Utility Model Application No. 56-132366), or a temperature-sensitive actuating member made of thermowax is provided in the control sleeve part (e.g., Utility Model Application No. 57-22671). Place the sleeve in the low temperature increase position during cold start,
A proposal has been made to return the injection amount to the normal position by the action of a temperature-sensitive operating member when starting at room temperature or above, to obtain a sufficient starting amount increase at low temperature starting, and to obtain an appropriate injection amount at starting at room temperature or above. .

Furthermore, in general, fuel injection pumps have a property that as the fuel temperature rises, the amount of fuel injected decreases as a result of expansion of various parts and other influences. This causes problems such as a decrease in horsepower due to a decrease in the amount of fuel injected when the engine is at high temperature, as well as a drop in engine speed and engine stalling during idling. To solve this problem, a temperature-sensitive actuating member that expands and contracts in proportion to temperature changes is installed in the full load adjusting screw part (for example, Utility Model Application No. 137617/1983), or a fixed fulcrum of the collector lever and a full load adjusting screw are installed. A temperature-sensitive actuating member that presses the collector lever between the engine and the piping screw is installed (for example, Utility Model Application No. 56-43470), and when the fuel temperature is high, the control sleeve is moved in the direction of increasing the injection amount to compensate for the temperature of the injection amount. Proposals have been made.

However, all of the above proposals either increase the fuel injection amount when the engine starts at a low temperature or increase the fuel injection amount when the fuel temperature rises, and cannot satisfy both temperature compensation requirements. Since the conventional temperature-sensitive actuating member is made of bimetal or thermowax, there is a problem in that the response to temperature changes is slow.

The present invention was made to solve the above problems, and includes a collector lever supported by a fixed support shaft and pressed against a full load adjusting screw by a support spring, and a tension lever supported by the support shaft on the collector lever. In a distribution type fuel injection pump in which a control sleeve controlled by a governor lever mechanism consisting of a start lever and a start lever changes the effective stroke of a plunger to increase or decrease the amount of fuel injection, the full load adjusting screw part and the support spring part Equipped with a temperature-sensitive actuating member made of a shape memory alloy, the collector lever rotates in the direction of increasing the injection amount when the fuel is low, returns to the direction of decreasing the injection amount at room temperature, and rotates in the direction of increasing the injection amount when the temperature is high. By setting the temperature-sensitive actuation member made of the shape memory alloy to
Increase in fuel injection amount when starting the engine at low temperature,
Temperature-compensated distribution type fuel that performs temperature compensation for both increasing the fuel injection amount when the fuel temperature rises, and that this temperature compensation responds instantaneously at a predetermined temperature by using a shape memory alloy as a temperature-sensitive actuating member. The purpose is to provide injection pumps.

An embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a vertical longitudinal sectional view showing an embodiment of the temperature compensated distribution type fuel injection pump according to the present invention;
The figure shows a detailed cross-sectional view of a full-load adjusting screw part that uses a temperature-sensitive actuating member made of a shape memory alloy, and Figure 3 shows a detailed cross-sectional view of a support spring part that uses a temperature-sensitive actuating member made of a shape memory alloy. In the present temperature compensated distribution type fuel injection pump shown in FIG. 1, fuel oil is sucked and pressurized from a fuel tank (not shown) by an oil feed pump 1, and is supplied to a pump chamber 3 in a pump housing 2. As is well known, the internal pressure of the pump chamber 3 is controlled by a pressure control valve (not shown) in relation to the engine speed, so that as the speed increases, the internal pressure increases in proportion.

A plunger barrel 4 attached to the pump housing 2 has a plunger 5 for pump and distribution.
is inserted, and the plunger 5 is caused to reciprocate and rotate at the same time by the following means. That is, the drive shaft 6 and the cam disk 7 fixed to the end of the plunger 5 are connected in the rotational direction via a driving disk (not shown), and the cam disk 7 has a cam surface corresponding to the number of cylinders of the engine. By pressing the cam surface against a roller 9 held in a roller holder 8 by a plunger spring 10, the plunger 5 is caused to simultaneously perform reciprocating motion for suction and pressure feeding of fuel and rotation for distribution.

When the plunger 5 is in the suction stroke, the fuel in the pump chamber 3 is supplied to the suction port 12 through the supply passage 11.
From there, it is supplied to the compression chamber 14 through one of the plurality of suction grooves 13 provided on the outer peripheral surface of the tip of the plunger 5.
When the plunger 5 moves to the pressure stroke, the suction port 12 and the suction groove 13 are separated, and the fuel in the compression chamber 14 is compressed, passing through the vertical hole 15 in the plunger 5 from the distribution port 16 to the distribution passage 17 (circular). The fuel is supplied to one of the cylinders (of which a number of cylinders are separately provided in the circumferential direction), and is injected into the cylinder from the delivery valve 18 through an injection nozzle (not shown).

In addition, a control sleeve 19 is slidably inserted into a portion of the plunger 5 that protrudes toward the pump chamber 3, and a cut-off port 20 connected to the vertical hole 15 of the plunger 5 is removed from the upper edge of the control sleeve 19. When opening into the pump chamber 3,
Since the fuel flows out into the pump chamber 3, the delivery to the delivery valve 18 is stopped and the injection ends.

The control sleeve 19 is connected to the plunger 5 via a governor lever mechanism 21 that engages with the plunger 5.
The upper position is controlled, thereby changing the effective stroke of the plunger 5 and adjusting the increase or decrease of the injection amount.

The governor lever mechanism 21 is the start lever 2
2. Tension lever 23 and collector lever 2
4, the collector lever 24 is pivotally supported by a fixed support shaft 25 fixed to the pump housing 2, and the start lever 22 and tension lever 23 are rotated by the collector lever 24 by a common support shaft 26 at the lower part. It is pivoted for free movement. Further, the counterclockwise rotation of the tension lever 23 is regulated by a stopper pin 27 fixed to the pump housing 2, and the full-load fuel injection amount during normal operation is determined by the position of the collector lever 24 and the stopper pin 27. .

The start lever 22 has a centrifugal force governor 40 on the front.
A start spring 28 is provided on the rear surface of the contact portion that the tip of the governor sleeve 41 comes into contact with, and the tip of the start spring 28 is in contact with the tension lever 23. Further, the lower end engages with the control sleeve 19 via an engagement ball 30.

The tension lever 23 is connected to the retaining pin 3 with a damper spring 31 interposed at its upper end.
2 and a control lever 34 via a governor spring 33 and operated by an accelerator pedal (not shown).
The spring force of the governor spring 33 is adjusted by this.

The collector lever 24 is rotatably supported by a fixed support shaft 25 fixed to the housing 2, and a full-load adjusting screw portion using a temperature-sensitive actuating member, which will be described later, is located above the fixed support shaft 25. (hereinafter referred to as the road screw portion) 50,
Its lower end is pressed by a support spring section 60 that also uses a temperature-sensitive actuating member, and the level of the full-load fuel injection amount is set to be variable.

A flyweight holder 43 is rotatably attached to the base of a governor shaft 42 of the centrifugal force governor 40, and the holder 43 is rotated in relation to engine rotation. A flyweight 44 is provided in the flyweight holder 43, and when the flyweight 44 is expanded by centrifugal force, it moves the governor sleeve 41 fitted into the tip of the governor shaft 42 to the right in the figure. The tip of the governor sleeve 41 is in contact with the start lever 22 of the governor mechanism 21.

Thus, the spring force of the governor spring 33 controlled by the control lever 34;
In the force relationship with the centrifugal force that acts on the flyweight 44 according to engine rotation,
The position of the control sleeve 19 is controlled via the tension lever 23.

In the load screw portion 50, a spring case 50b is fitted into an adjusting screw 50a which is screwed into the position of a conventional load screw so as to be able to move forward and _backward . A double spring with a shape memory spring _M1 made of a reversible shape memory alloy as a temperature-sensitive actuation member on the inside is elastically installed, and presses the upper end of the collector lever 24 with the tip of the spring case 50b. .

Further, the support spring portion 60 has a spring case 60 in the position of a conventional support spring.
A is fitted so as to be movable back and forth, and a normal spring _S2 made of a general spring material similar to that of the load screw part 50 is placed outside, and a shape memory spring M made of a reversible shape memory alloy as a temperature-sensitive actuating member is inserted into the spring S2. A double spring with ₂ facing inside is elastically installed, and the lower end of the collector lever 24 is pressed by the tip of the spring case 60a. Note that the above-mentioned double spring consisting of shape memory springs M ₁ and M ₂ and normal springs S ₁ and S ₂ is functionally the same even if the outer side is replaced with a shape memory spring and the inner side is replaced with a normal spring.

Here, the spring M ₁ provided in the load screw part 50 and the support spring part 60,
The relationship between S ₁ , M ₂ , and S ₂ is set as described below. That is, the shape memory spring M ₁ provided in the load screw portion 50 is maintained at a predetermined temperature (transformation temperature).
The shape is reversibly memorized so that the spring length is elongated at low temperatures below, and shortened at room temperature to high temperatures higher than this transformation temperature. On the other hand, the shape memory spring _M2 provided in the support spring section 60 expands in spring length in the range of low temperature to room temperature, and reaches a predetermined temperature (transformation temperature).
At higher temperatures, the shape is reversibly memorized so that the spring length is shortened. Ordinary spring
The strength of S ₁ and S ₂ is set to S ₁ > S ₂ , and the shape memory spring M ₁ is in an elongated shape at low temperature.
Alternatively, the resultant force of M ₂ and the normal spring S ₁ or S ₂ is set as M ₁ +S ₁ >M ₂ +S ₂ .

In the above configuration, when the fuel is at a low temperature below a predetermined temperature, the shape memory spring M ₁ of the load screw portion 50 is expanded, and the shape memory spring M ₂ of the support spring portion 60 is already expanded, and the load screw portion 50 and the support Spring part 60
Conformal memory spring M ₁ , M ₂ and normal spring
The resultant force of S ₁ and S ₂ acts, and this resultant force is M ₁ + S ₁ >
Since it is set to M ₂ + S ₂ , the collector lever 2
4 is rotated counterclockwise in the figure with the fixed support shaft 25 as a fulcrum to raise the level of the full load fuel injection amount, and the control sleeve 19 is rotated by the start lever 22,
It is moved to the low temperature start increase position via the engagement ball 30. Therefore, the injection amount is increased, and the engine starts smoothly at low temperatures.

When the engine is rotated and the fuel temperature exceeds the transformation temperature of the shape memory spring M ₁ of the load screw portion 50 and reaches room temperature, this shape memory spring M ₁
is shortened, and the spring force of only the general spring _S1 acts on the load screw portion 50. On the other hand, the shape memory spring _M2 of the support spring section 60 is
Since room temperature is also below the transformation temperature, the length remains extended, and a spring force of M ₂ +S ₂ acts on the support spring portion 60. Therefore, since the spring force is S ₁ <M ₂ +S ₂ , the collector lever 24 is rotated clockwise in the figure, and the full load fuel injection amount is reduced and returned to the normal level, and the control lever 34 and governor mechanism 21 Normal injection amount control is performed. When the fuel temperature is at room temperature, the engine is started at the normal level as described above, so that the emission of black smoke due to an excessive injection amount at the time of starting is prevented.

In addition, when the fuel temperature becomes higher than normal temperature due to engine usage conditions or external influences, the shape memory spring _M1 of the load screw portion 50 is already above the transformation temperature, so its length is shortened and the load screw portion 50 is shortened. The spring force of only the general spring _S1 acts. On the other hand, the support spring part 60
The shape memory spring _M2 reaches a high transformation temperature and is shortened, so that only the spring force of the general spring _S2 acts on the support spring part 60. The spring force of general springs S ₁ and S ₂ is
Since S ₁ > S ₂ is set, collector lever 2
4 is rotated counterclockwise in the figure from the normal level to raise the level of the full load fuel injection amount and move the control sleeve 19 to the position where the injection amount is increased. Therefore, the decrease in injection amount due to high-temperature fuel is compensated for by an appropriate amount, and problems such as a decrease in engine horsepower, drop in engine speed during idle rotation, and occurrence of engine stall are eliminated.

The temperature compensation of the injection amount described above is such that the load screw section 50 compensates for the increase in the starting amount at low temperatures, and the support spring section 60 compensates for the decrease in the injection amount at high temperatures. In order to compensate for the decrease in the injection amount at high temperatures, the support spring section 60 can also be used to increase the starting amount at low temperatures.

In this case, the shape memory spring M ₁ of the load screw section 50 expands at a high temperature above a predetermined temperature (transformation temperature), shortens at a temperature ranging from room temperature to low temperature below this transformation temperature, and the shape memory spring M 1 of the support spring section 60 ₂ is the specified temperature (transformation temperature)
A shape memory spring whose shape is reversibly memorized is used so that it shortens at a low temperature below and expands at a room temperature to a high temperature above the transformation temperature. Also, the spring force of the general springs S ₁ and S ₂ is the same as above, S ₁
＞S ₂ and the resultant force of the shape memory spring M ₁ or M ₂ which is in an expanded shape at high temperature and the normal spring S ₁ or S ₂ is M ₁ +S ₁ ＞
Set to M ₂ + S ₂ .

Therefore, at low temperatures, the shape memory spring _M1 in the load screw portion 50 is shortened and becomes a normal spring.
Only the normal spring S ₁ acts, and in the support spring part 60, the shape memory spring M ₂ is shortened, so only the normal spring S ₂ acts, and the spring force S ₁
> _S2 , the collector lever 24 rotates counterclockwise in the figure, moves the control sleeve 19 to the cold start increase position, and the injection amount is increased at the cold start.

At room temperature, the shape memory spring _M2 remains shortened in the load screw portion 50 and becomes a normal spring.
Only S ₁ acts, and the shape memory spring M ₂ expands in the support spring section 60, and the resultant force M ₂ + S ₂ of the shape memory spring M ₂ and the normal spring S ₂ acts, and S ₁ < M ₂ + S ₂ . Therefore, the collector lever 24 rotates clockwise in the drawing, and moves the control sleeve 19 to a position that provides a normal injection amount.

At high temperatures, the shape memory spring M ₁ expands in the load screw portion 50, resulting in the resultant force of the shape memory spring M ₁ and the normal spring S ₁ , M ₁ +
S ₁ acts, shape memory spring M ₂ is expanded in the support spring part 60, and the resultant force M ₂ + S ₂ of the normal spring S ₂ acts, and the spring force is
Since M ₁ +S ₁ >M ₂ +S ₂ , the collector lever 24
is rotated counterclockwise in the figure to move the control sleeve 19 to a position where the injection amount is increased, and the injection amount is compensated for the high temperature.

As explained above, the present invention includes a collector lever supported by a fixed support shaft and pressed against a full load adjusting screw by a support spring, a tension lever supported by a support shaft on the collector lever, and a tension lever supported by a support shaft on the collector lever. In a distribution type fuel injection pump in which a control sleeve controlled by a governor lever mechanism consisting of a start lever changes the effective stroke of a plunger to increase or decrease the fuel injection amount, the full load adjusting screw part and the support spring part are made of shape memory alloy. A temperature-sensitive actuating member is installed, and the collector lever is rotated in the direction of increasing the injection amount when the fuel is low, returns to the direction of decreasing the injection amount when the fuel is at room temperature, and rotates in the direction of increasing the injection amount when the temperature is high. By setting the temperature-sensitive actuating member made of the shape memory alloy, the injection amount is increased when the engine is started at a low temperature to obtain good startability, and when the engine is started at room temperature, the injection amount is returned to the normal level and when the engine is started. This prevents the emission of black smoke due to excessive injection amount, and also compensates for the decrease in injection amount to the appropriate amount at high temperatures, eliminating problems such as a drop in engine horsepower, drop in rotation at idle, and even engine stalling. . The above-mentioned temperature compensation of the injection amount is instantaneously and reliably effected at a predetermined temperature by using a shape memory alloy as the temperature-sensitive operating member, compared to conventional thermowaxes or bimetals.

Also, compared to models that use an external actuator such as a step motor to rotate the collector lever, there is no actuator around the pump housing.
There is no need to install ECU or sensors, etc.
It can meet the demands for space saving and cost reduction.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a vertical longitudinal sectional view, FIG. 2 is a detailed sectional view of a full-load adjusting screw part using a temperature-sensitive actuating member made of a shape memory alloy, and FIG. 1 is a detailed sectional view of a support spring portion using a temperature-sensitive actuating member made of a shape memory alloy. 3...Pump chamber, 5...Plunger, 19...
Control sleeve, 21... Governor lever mechanism, 22... Start lever, 23... Tension lever, 24... Collector lever, 25... Fixed support shaft, 50... Full load adjusting screw portion, 60... Support spring part, M ₁ ,
M ₂ ... shape memory spring, S ₁ , S ₂ ... ordinary spring.

Claims (1)

[Scope of utility model registration request] It is controlled by a governor lever mechanism consisting of a collector lever supported by a fixed support shaft and pressed against a full load adjusting screw by a support spring, and a tension lever and a start lever supported by a support shaft on the collector lever. In a distribution type fuel injection pump in which a control sleeve changes the effective stroke of a plunger to increase or decrease the fuel injection amount, a temperature-sensitive actuating member made of a shape memory alloy is arranged in the full load adjusting screw part and the support spring part, respectively. When the temperature of the fuel is low, one of the temperature-sensitive operating members rotates the collector lever in the direction of increasing the injection amount, and when the fuel is at room temperature, the collector lever is rotated in the direction of decreasing the injection amount, and when the fuel is still hot, the other temperature-sensitive operating member rotates the collector lever. A temperature-compensated distribution type fuel injection pump, characterized in that the temperature-sensitive actuating member made of the shape memory alloy is set so as to rotate the collector lever in the direction of increasing the injection amount.