JP2001349262A - Injection timing control mechanism for fuel injection pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the increase of the number of high idle rotation at a ordinary temperature and the increase of the exhaust amount of NOx in an injection timing control mechanism for a fuel injection pump having improved low-temperature startability by performing spark-advance control at a low temperature with a temperature sensitive member. SOLUTION: The injection timing control mechanism comprises a sub-port to be opened at an inner wall face of a plunger barrel for draining part of a fuel oil when the fuel oil sucked from a fuel gallery into the plunger barrel is forcibly fed by a plunger, a drain passage communicated with the sub-port, a valve element for opening/closing the drain passage with the change of a passage area Ap of the drain passage, and the temperature sensitive member for displacing the valve element in response to a change in temperature. With the passage area Ap of the drain passage being equal to an area As of an opening portion of the sub-port (Ap=As), a temperature Tp of the temperature sensitive member 46 is not higher than 5 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an injection timing control mechanism for a fuel injection pump. More specifically, the present invention relates to a configuration for improving the engine startability at a low temperature in a fuel injection pump and obtaining desired performance immediately after the engine is started.

[0002]

2. Description of the Related Art In a diesel engine, fuel pressurized to several hundred atmospheres by a fuel injection pump is supplied to a cylinder chamber through a high-pressure pipe nozzle, and the crank rotation angle is about 20 ° ahead (leading) of the top dead center at a crank rotation angle. (Angle), the fuel is injected into the combustion chamber from the injection port of the injection valve. Diesel engines burn in excess air, so they emit lower concentrations of CO and HC than gasoline engines, but emit NOx to the same extent, so reducing them is an important issue.

[0003] As an effective means for reducing this NOx, there is known a method of retarding the fuel injection timing.
That is, this is a method of delaying the timing of fuel pumping of the fuel injection pump to delay the fuel injection timing in the cylinder. However, since this method is to reduce the amount of NOx emission due to the deterioration of the combustion state, various inconveniences such as deterioration of low-temperature startability are caused. Therefore, there is a demand for a technique for maintaining low-temperature startability of an engine while suppressing NOx emissions.

[0004]

As means for solving this problem, Japanese Patent Application No. 11-359 filed by the same applicant has been proposed.
No. 51 discloses an injection timing control structure technology. This technique forms a fuel pressure chamber 44 between the plunger 7 and the plunger barrel 8 as shown in FIG.
This is applied to a fuel injection pump that sucks fuel into the fuel pressure chamber 44 through the main port 14 and feeds it to the communication passage 49 to the distribution shaft. The outline thereof is to form a fuel drain circuit for draining fuel from the fuel pressure chamber 44 via the sub port 42, and in the fuel drain circuit,
An on-off valve structure is formed in which a displaceable valve body 46 having an oil-tight function slides. The valve body 46 is made openable and closable with respect to the sub-port 42. This is configured to be performed by the warming / sensing member 47 that expands and contracts. Thus, when the engine is at room temperature,
As shown in FIG. 2, the valve element 46 opens the sub port 42 to drain a part of the fuel, and lowers the pressure of the fuel pressure chamber 44 so that the fuel injection timing can be retarded. On the other hand, when the engine is at a low temperature, the fuel is not drained because the valve body 46 closes the subport 42 as shown in FIG. 13, the pressure in the fuel pressure chamber 44 becomes higher than that at normal temperature, and the fuel injection timing becomes can do.

[0005] This warm sensation member is described in Japanese Patent Application No.
In the example of -35951, it is disclosed that a wax pellet-type thermostat that contracts in a low temperature range, expands in a high temperature range, and expands and contracts using the expansion coefficient of the wax can be used. A configuration example of the thermostat shown in FIG. 14 will be described. A wax 201 having fluidity is sealed in a cup 202 and sealed with a sleeve 203 made of a flexible material. A cylindrical portion is formed on the sleeve 203, and a piston 204 is slidably fitted to the cylindrical portion, and the piston is mounted on the cover 205 of the cup 202 so as to be axially displaceable. I support it. Therefore, when the wax 201 expands due to the temperature rise, the piston 2
The pressure in the direction of pushing out the piston 04 is applied to the sleeve 203, and the piston 204 is driven to extend.

According to this configuration, when the engine is at a low temperature, the fuel injection timing is controlled to the advanced side, so that misfire can be suppressed and low temperature startability can be improved. Is higher than a certain temperature, the fuel injection timing is controlled to the retard side so that N
Ox emissions can be reduced. FIG. 16 shows an experiment in which the engine is started in a low-temperature environment, and shows a change in the rotation speed immediately after the start. The engine having the low-temperature advance angle control structure is compared with an engine having no such structure.
Immediately after starting, it was recognized that the rotation speed was increased,
It can be seen that the low temperature startability has been improved.

Here, the above-described control for setting the fuel injection timing to the advanced side (hereinafter referred to as "advance control") is no longer necessary if the engine is successfully started at a low temperature. It is desirable to adopt a structure in which once the start of the engine is started, the advance angle control is immediately released. In other words, in this technology, when setting the fuel injection timing so that the engine output and the number of revolutions become the expected values, it is assumed that the injection timing is controlled to the retard side at normal temperature. In general, if the advance angle control is performed at room temperature,
The engine output and the number of revolutions are additionally added by the amount of the advance angle control, so that the desired output and the number of revolutions cannot be obtained, and the NOx emission increases.

In this respect, the above-described fuel injection timing control structure can cause a state in which the advance angle control is not released for a long time after the start of the engine. Therefore, although it is good that the engine was successfully started in a low temperature environment, the fuel injection timing is still controlled to the advanced side even though the engine has been warmed to a temperature of about room temperature,
As a result, a state occurs in which the engine output and the engine speed exceed the expected ones, and the states may be maintained for a long time after the engine is started.
FIG. 17 is a graph obtained by reducing the time axis of the graph of FIG. 16 to 1/30. It is recognized that the actual number of revolutions exceeds the set number of revolutions, and it is presumed that the advance angle control is performed at this point in spite of the fact that the engine has been warmed to about room temperature. As the time elapses, the temperature-sensing member that has detected a further increase in the temperature releases the advance angle control and gradually approaches the set rotation speed. However, even after 1500 seconds, the set rotation speed slightly exceeds the set rotation speed. It is recognized that.

Further, if the above-described warming member 47 is broken, the valve body 46 cannot be driven, so that a state in which the switching is not performed while the advance control or the retard control is being performed may occur. For example, when the wax pellet type thermostat as described above is used as the warming member 47,
If the wax 201 leaks due to any situation, the piston 204 is retracted beyond its limit, and the piston 204 is retracted beyond the normal movable range. As shown in FIG. Therefore, it is permanently closed, and as a structure, the advance angle control is always performed. As described above, if the advance angle control is always performed regardless of whether the temperature is low or not, the engine output and the engine speed at room temperature exceed those expected at normal temperature after the damage of the warming member 47. , NOx emissions also increase forever. Therefore, it is also desirable to be able to deal with such a situation.

[0010]

The problems to be solved by the present invention are as described above. Next, means for solving the problems will be described.

That is, in the first aspect, an opening is formed in the inner wall surface of the plunger barrel for draining a part of the fuel oil when the fuel oil sucked from the fuel gallery into the plunger barrel is pumped by the plunger. Sub-port, a drain passage communicating with the sub-port, a valve body for opening and closing the drain passage by changing a passage area of the drain passage, and displacing the valve body according to a change in temperature. A warming member, and wherein the temperature of the warming member when the area of the drain passage becomes equal to the area of the opening of the subport is 5 ° C. or less.

According to a second aspect of the present invention, when fuel oil sucked into the plunger barrel from the fuel gallery is pressure-fed by the plunger, a drain circuit for draining part of the fuel oil, and a valve for opening and closing the path A body, and a warming member that expands and contracts in response to a change in temperature and displaces the valve body, wherein the valve body pushed by extension of the warming member opens the drain circuit, and the warming member The valve element retracted by the contraction of the valve is configured to close the drain circuit,
Further, a passage is provided for opening the drain circuit when the valve body is retracted due to loss of extension force due to occurrence of an abnormality in the warm sensation member.

[0013]

Next, embodiments of the present invention will be described. FIG. 1 is a cross-sectional view showing an overall configuration of a fuel injection pump according to a first embodiment of the present invention, FIG. 2 is an enlarged cross-sectional view showing a configuration of an injection timing control mechanism, and FIG. 3 is a passage area of a drain passage. FIG. 7 is a diagram showing a state in which is changed and an opening of a subport. FIG. 4 is a view showing a state in which the low-temperature advance control is performed in the injection timing control mechanism, and FIG. 5 is a view showing a state in which the low-temperature advance control is released.
FIG. 6 is a diagram showing a relationship between the effective area of the opening and the temperature detected by the warming member. FIG. 7 is a graph showing a change in the number of revolutions immediately after the start of the engine in the injection timing control mechanism of the present invention. FIG. 8 is a graph showing the time axis of the graph of FIG.

First, a schematic configuration of the fuel injection pump of the present invention will be described. A camshaft 4 is provided horizontally below the fuel injection pump 1 shown in FIG. 1, and one end of the camshaft 4 is rotatably supported by a main body housing H via a cam bearing 12. A cam 5 is fixed to the cam shaft 4, and a plunger barrel 8 is provided above the cam 5. A plunger 7 is inserted into the plunger barrel 8 so as to be vertically slidable, and a tappet 11 is attached to a lower end of the plunger 7. Plunger 7 and tappet 11 are spring 1
5, the tappet 11 comes into contact with the peripheral edge of the cam 5, and the rotation of the cam 5 causes the plunger 7 to move up and down. Plunger 7
A distributing shaft (not shown) is rotatably arranged with the axis parallel to the plunger 7, and the power of the cam shaft 4 is transmitted and transmitted by a bevel gear (not shown). A trochoid pump driven by the rotation of the camshaft 4 is provided in the housing H (not shown), and the fuel oil stored in the fuel tank is supplied to the trochoid pump via a delivery passage connected to a delivery port of the trochoid pump. To supply it to the fuel gallery 43.

As shown in FIG. 2, a fuel pressure chamber 44 for pressurizing the introduced fuel is formed inside the plunger barrel 8 above the plunger 7. In the plunger barrel 8, a communication passage 49 to the main port 14 and the distribution shaft is provided so as to be able to communicate with the fuel pressure chamber 44. The main port 14 is provided with a fuel supply oil passage and a fuel gallery 43 formed in a housing of the fuel pump.
, And the fuel is always supplied. Therefore, the main port 14 from the fuel gallery 43
Is introduced into the fuel pressure chamber 44 through the plunger 7 and pressurized by the plunger 7 to form a communication passage 49 to a distribution shaft provided on the upper portion of the plunger barrel 8 and a communication passage with the communication passage 49. The fuel is fed to the distribution shaft through the fuel feed passage 21. The fuel oil is supplied to the plurality of delivery valves while being distributed by the rotation of the distribution shaft, and the fuel supplied to each delivery valve is pressure-fed to the injection nozzle and injected. Reference numeral 16 denotes a plunger lead for determining an effective stroke of the plunger 7 for fuel pumping.
By rotating the plunger 7 about the axis, the height of the plunger 7 when the plunger lead 16 communicates with the main port 14 can be changed.

A sub-port 42 is opened on the inner wall surface of the plunger barrel 8, and the sub-port 42 is formed on the upper end surface 7a of the plunger 7 for compressing fuel in a fuel pressure chamber 44 formed inside the plunger barrel 8. A sub-lead 7b is provided on the same side as the side on which plunger 7 is formed so as to be able to communicate with sub-port 42 within a certain rotation range of plunger 7, and main port 14 is closed by the outer peripheral surface of plunger 7. Also, the fuel pressure chamber 44 and the sub port 42 can be communicated via the sub lead 7b. An oil passage 81 is provided in the plunger barrel 8 in the radial direction so as to communicate with the sub port 42.
Is connected to a groove 82 formed in the outer peripheral surface of the plunger barrel 8 in parallel with the axial direction. The groove 82 communicates with a valve chamber oil passage 45 also formed in the housing H via a communication passage 83 formed in the housing H. The valve chamber oil passage 4
Reference numeral 5 communicates with the fuel gallery 43 via a return oil passage 84. A drain passage 99 is configured by the oil passage 81, the groove 82, and the communication passage 83.
The valve circuit oil passage 45 and the return oil passage 84 constitute a drain circuit 90 for returning the fuel oil in the fuel pressure chamber 44 to the fuel gallery 43. However, the drain circuit may be configured to return fuel to the fuel tank outside the housing H.

In this configuration, the outer peripheral surface of the head of the plunger 7 closes the main port 14 before reaching the top dead center when the plunger 7 slides up and down, so that the fuel pressure chamber 44 communicates with the distribution shaft. The fuel pressure feeding to the passage 49 is started in the advance range of the cam angle. In this advance angle range, since the sub-lead 7b is in communication with the sub-port 42, the fuel is drained from the sub-port 42 to delay the start of the fuel pumping despite the plunger 7 sliding upward. Can be. Incidentally, the degree of delay in the start timing of the fuel pumping can be adjusted by adjusting the depth of the sub-lead 7b and the height of the sub-port 42.

A valve body 46 is displaceably and oil-tightly fitted in the valve chamber oil passage 45, and a warming member 47 for driving the valve body is provided in the valve chamber oil passage 45. Can be In the present embodiment, the warming sensation member 47 is a wax pellet-type thermostat that contracts in a low-temperature region and expands in a high-temperature region and expands and contracts by using the expansion coefficient of the wax, as shown in FIG. Piston 2 which is a telescopic movable part
04 is fixed to the valve body 46. The valve body 46 has an oil passage 8
5 are provided so as to be parallel to the axial direction. A return spring 48 is provided on the opposite side of the warming member 47 with the valve body 46 interposed therebetween, and applies a biasing force against the extension driving of the warming member 47 to the valve body 46.

In this configuration, when the temperature sensing member 47 detects the temperature rise and extends the piston 204, the valve body 46
Compresses the return spring 48, and the return spring 48 increases its elastic force. Therefore, the valve body 46
Is stopped at an equilibrium position where the tension of the warming member 47 and the elasticity of the return spring 48 are balanced, and the position is determined according to the temperature detected by the warming member 47. One end of the communication passage 83 forms an opening P in the wall surface of the valve chamber oil passage 45, and the opening P can be opened and closed by the outer peripheral surface of the valve body 46.

In this configuration, when the engine is in a low-temperature environment, the warming member 47 retracts the piston 204, so that the valve body 46 to which the return force is applied by the return spring 48 is, as shown in FIG. The outer peripheral surface is driven so as to completely close the opening P. Therefore, the sub port 42 is closed, the fuel is not drained, and the start timing of the fuel pumping is not delayed. When the temperature of the engine rises from this state, the warm sensation member 47 drives the piston 204 to extend and displace the valve body 46 downward in FIG. 4, and the outer peripheral surface of the valve body 46 gradually opens the opening P. To gradually increase the passage area of the drain passage. Therefore, as the temperature rises, the opening of the subport 42 increases, the amount of fuel drain increases, and the start timing of fuel pumping is gradually delayed. And finally as shown in FIG. 5, the passage area A _p of the drain passage 99 becomes equal to the area A _s of the opening of the sub-port 42, drain passage 99 to the sub port 42 is fully opened, the start timing Is delayed by a predetermined timing.
That is, when the temperature is low, the sub port 42 is closed and the start timing of the fuel pumping is not delayed so that the advance angle control is performed.
At high temperature (normal temperature), the sub port 42 is opened to delay the start timing, thereby canceling the advance control.

FIG. 6 is a graph showing the above relationship.
In this graph, the horizontal axis represents the temperature of the temperature sensing member 47 and
The vertical axis represents the effective area of the opening P (that is, the opening P).
The fuel oil can be circulated without being closed by the valve body 46.
Area of the portion, in other words, of the drain passage 99
Passage area) A_pIs taken. According to this graph
In other words, at low temperatures below -25 degrees Celsius
In this case, the outer peripheral surface of the valve body 46 completely closes the opening P.
And the area A of the drain passage _pIs zero. So
Then, as the temperature rises, the warm sensation member 47
The valve body 46 is displaced by moving the
When the opening P starts to open, the drain passage 99 is opened.
Area A_pGradually increase and open.

[0022] In the present invention, the temperature at which the drain circuit 90 is fully opened to sub port 42, i.e., in the opening area (the graph of the area A _p is the sub-port 42 of the drain passage in A _S when displacing the valve body to be equal to shown), the temperature T _p of the warming member is detecting is than 5 ° C. is adjusted to be lower. When the temperature T _p is greater than 5 ° C., become the engine warms are nevertheless advance control is not canceled, the output and the rotational speed of the engine so that the excess of those expected unfavorable . This adjustment can be performed by appropriately determining the characteristics of the warming member 47, the spring force of the return spring 48, the position and shape of the opening P, and the like.

With the above-described adjustment, when the engine temperature is low, the advance angle control is performed to maintain good engine startability, and when the temperature of the warming member reaches 5 ° C., the sub port 42 is no longer used. Is fully opened and the advance control is completely released, so that when the engine is started and the engine warms up, the advance control is immediately released,
Engine power and speed may exceed what is expected,
A situation in which the NOx emission increases or the like is prevented.

The graphs shown in FIGS. 7 and 8 show the transition of the number of revolutions at the time of low temperature start in the engine to which the injection timing control mechanism of the present invention is applied. The engine injection timing control mechanism of the present invention used for this measurement is adjusted so that the subport 42 is completely opened when the temperature sensing member reaches 0 ° C. (T _p = 0 ° C.). This engine
As shown in FIG. 7, the startability at low temperature is as excellent as the engine injection timing control structure of Japanese Patent Application No. 11-35951, but after the engine is started, as shown in FIG. As in the case of the injection timing control structure disclosed in Japanese Patent Application Laid-Open No. 11-35551, it does not exceed the set rotation speed, and it is recognized that the set rotation speed is stably maintained 300 seconds after the start.

Next, a description will be given of an embodiment of a fuel injection pump having a structure in which the advance angle control can be released in the event that the heat sensing member is broken. FIG. 9 is a sectional view showing the overall configuration of a fuel injection pump according to a second embodiment of the present invention. FIG. 10 is an enlarged sectional view showing the configuration of the injection timing control mechanism.

In the fuel injection pump 1 'according to this embodiment, as shown in FIG. 9, a passage 93 is provided in the valve body 46 so as to be able to communicate with the subport 42 described above. As shown in FIG. 10, the specific configuration of the passage 93 is such that an annular groove 94 is provided on the outer peripheral surface of the valve
A communication hole 95 is formed in the diameter direction of No. 6 to communicate with the annular groove 94. The communication hole 95 communicates with the oil passage 85 provided in parallel with the axial direction of the valve body 46. Other configurations are the same as the configuration of the fuel injection pump 1 described above.

In this configuration, even if the temperature sensing member 47 is damaged and the piston 204 is retracted out of the normal range and the valve body 46 is retracted beyond the limit as shown in FIG. The annular groove 94 is communicated with the subport 42 through the communication passage 83, so that the subport 42
Thus, a path through which fuel is drained is secured, and the advance angle control is released. Therefore, such a temperature-sensitive member 47
Even in the event of breakage, the advance control is reliably released, preventing the engine output and the number of revolutions at room temperature from exceeding the expected values and preventing the NOx emission from increasing.

[0028]

The present invention is configured as described above.
The following effects are obtained.

That is, an opening is formed in the inner wall of the plunger barrel for draining a part of the fuel oil when the fuel oil sucked from the fuel gallery into the plunger barrel is pumped by the plunger. Sub-port, a drain passage communicating with the sub-port, a valve body for opening and closing the drain passage by changing a passage area of the drain passage, and displacing the valve body in accordance with a change in temperature. And the temperature of the warming member when the area of the drain passage is equal to the area of the opening of the subport is 5 ° C. or less. Under the advance control to prevent the fuel oil from being drained,
It has excellent engine startability, and can easily start the engine even in cold regions and in winter. On the other hand, once the engine is started and the engine warms up, the advance angle control is completely released immediately, so that a situation such as an increase in the NOx emission amount after the engine is started or an increase in the high idle speed is prevented.

According to a second aspect of the present invention, when fuel oil sucked from the fuel gallery into the plunger barrel is pumped by the plunger, a drain circuit for draining a part of the fuel oil and opening and closing the path are provided. A valve body, and a warming member that expands and contracts in response to a change in temperature to displace the valve body, wherein the valve body pushed by the expansion of the warming member opens the drain circuit, The valve body retracted by the contraction of the member is configured to close the drain circuit,
Further, when the valve body is retracted due to the occurrence of an abnormality in the warm sensation member and the loss of tension, the passage for opening the drain circuit is provided, so that the drain circuit is closed in a low temperature environment. As a result, advance control is performed to prevent fuel oil from being drained, so that the engine is excellent in startability and the engine can be started easily even in a cold region or in winter. Furthermore,
Even if an abnormality occurs in the thermal sensation member and the valve body is retracted, the drain circuit is opened by the passage and the advance control is released. In such a case, the engine can be started at normal temperature in the same manner as in normal operation, and the situation such as an increase in NOx emission and an increase in high idle speed is prevented. You.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an overall configuration of a fuel injection pump according to a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing a configuration of an injection timing control mechanism.

FIG. 3 is a diagram illustrating a state where a passage area of a drain passage is changed and an opening of a subport.

FIG. 4 is a view showing a state in which a low-temperature advance angle control is performed in the injection timing control mechanism.

FIG. 5 is a diagram showing a state in which the low temperature advance angle control is released.

FIG. 6 is a view showing a relationship between a passage area of a drain passage and a temperature of a warming member.

FIG. 7 is a graph showing a change in the number of revolutions immediately after starting the engine in the injection timing control mechanism of the present invention.

8 is a graph in which the time axis of the graph of FIG. 7 is reduced to 1/30.

FIG. 9 is a cross-sectional view showing an overall configuration of a fuel injection pump according to a second embodiment of the present invention.

FIG. 10 is an enlarged sectional view showing the configuration of an injection timing control mechanism.

FIG. 11 is a diagram showing a configuration of an injection timing control mechanism disclosed in Japanese Patent Application No. 11-35951.

FIG. 12 is a diagram showing a state in which advance angle control is released in the injection timing control mechanism.

FIG. 13 is a diagram showing a state in which advance angle control is being performed.

FIG. 14 is a cross-sectional view illustrating a configuration example of a warming member.

FIG. 15 is a view showing a state where the temperature has risen from the state of FIG. 14 and the piston has been extended.

FIG. 16 is a graph showing a change in the number of revolutions immediately after the start of the engine in the injection timing control mechanism disclosed in Japanese Patent Application No. 11-35951.

FIG. 17 is a graph obtained by reducing the time axis of the graph of FIG. 16 to 1/30.

FIG. 18 is a view showing a state in which the heat sensation member has been damaged and the subport has been closed.

[Explanation of symbols]

 7 Plunger 8 Plunger barrel 43 Fuel gallery 46 Valve 47 Heating member 90 Drain circuit 93 Passage 99 Drain passage

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02M 59/46 F02M 59/46 Y (72) Inventor Junichi Samo 1st Chayamacho, Kita-ku, Osaka-shi, Osaka No. 32 Inside Yanmar Diesel Co., Ltd. (72) Inventor Toru Ogawa 1-32 Chayacho, Kita-ku, Osaka, Osaka Prefecture F-term inside Yanmar Diesel Co., Ltd. 3G060 AB01 BA22 BB14 CA02 CB01 CB02 DA00 DA08 EA00 FA02 GA05 3G066 AA07 AB02 AD12 BA25 BA53 CA01S CA08 CA09 CA11 CA33 CE02 DA04 DB01 DB04 DC14

Claims (2)

[Claims] 1. A sub-port opened on an inner wall surface of the plunger barrel for draining a part of the fuel oil when the fuel oil sucked into the plunger barrel from the fuel gallery is pumped by the plunger. A drain passage communicating with the valve body, a valve body for opening and closing the drain passage by changing the passage area of the drain passage, and a warming member for displacing the valve body in accordance with a change in temperature. An injection timing control mechanism for a fuel injection pump, wherein the temperature of the warming member when the area of the drain passage is equal to the area of the opening of the subport is 5 ° C. or less. 2. A drain circuit for draining a part of the fuel oil when the fuel oil sucked into the plunger barrel from the fuel gallery is pumped by the plunger, a valve for opening and closing the passage, and a temperature. A warming member that expands and contracts according to the change of the valve body to displace the valve body, wherein the valve body pushed and pushed by the expansion of the warming member opens the drain circuit and retreats due to the contraction of the warming member. The valve body is configured to close the drain circuit, and further, when the valve body is retracted due to the occurrence of an abnormality in the warm sensation member and loss of extension force, the drain circuit is opened. An injection timing control mechanism for a fuel injection pump, comprising: