JP2013204498A - Fuel injection pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injection pump 1 in which a start defect of a diesel engine 40 caused by freezing moisture deposited on a control rack 20 is prevented.SOLUTION: The fuel injection pump 1 is provided for the diesel engine 40 in which a control rack 20 for adjusting a fuel injection amount is disposed inside of a rack chamber 5 comprised of a pump head 3 and a pump housing 2. A glow plug 22 is provided which is a heating means for heating the rack chamber 5 and the control rack 20.

Description

  The present invention relates to a fuel injection pump of a fuel injection device, and more particularly to a technique for preventing freezing of a control rack.

  Conventionally, a fuel injection pump for an engine in which a control rack is arranged in a rack chamber formed by a pump head and a pump housing is known. By operating the control rack, the amount of fuel supplied to the engine by the fuel injection pump can be adjusted. In such a fuel injection pump, the amount of fuel supplied when starting the engine in the low temperature state is increased from the amount of fuel supplied when starting the engine in the normal temperature state, thereby improving the startability of the engine. There is something. For example, as described in Patent Document 1.

  The fuel injection pump described in Patent Document 1 switches the stopper position of the link that moves the control rack according to the temperature state of the engine. Thereby, the starting amount of the engine is improved by changing the movement amount of the control rack. However, when the moisture contained in the blow-by gas entering from the engine is condensed and adhered to the control rack, the moisture freezes on the control rack when the temperature around the control rack falls below the freezing point. As a result, the control rack may not move due to ice droplets, and fuel may not be supplied to the engine.

JP-A-8-128335

  The present invention has been made in view of the above situation, and an object of the present invention is to provide a fuel injection pump that prevents engine start failure due to freezing of water adhering to a control rack.

  In other words, according to the first aspect of the present invention, there is provided a fuel injection pump for an engine in which a control rack for adjusting a fuel injection amount is disposed inside a rack chamber formed by a pump head and a pump housing. A heating means for heating the rack is provided.

  According to a second aspect of the present invention, the apparatus further includes a control device, and starts heating of the heating means when the engine cooling water temperature is equal to or lower than a predetermined temperature when the engine is turned on and ends the heating after a predetermined time elapses It is.

  According to a third aspect of the present invention, the heating means is composed of a glow plug and is detachably provided on the pump head.

  According to a fourth aspect of the present invention, the heating means includes a plate heater and is provided on the inner wall of the rack chamber.

  According to a fifth aspect of the present invention, the control rack is colored black.

  As effects of the present invention, the following effects can be obtained.

  That is, according to the first aspect of the present invention, even if water is frozen and ice droplets are generated inside the rack chamber, it can be dissolved by the heating means. This prevents starting failure of the engine due to freezing of water adhering to the control rack.

  According to the second aspect of the present invention, the interior of the rack chamber is heated when there is a possibility of moisture freezing inside the rack chamber. This prevents starting failure of the engine due to freezing of water adhering to the control rack.

  According to the invention which concerns on Claim 3, a heating means can be easily provided in the inside of a rack chamber. Moreover, even if the heating means fails, it can be easily replaced. This prevents starting failure of the engine due to freezing of water adhering to the control rack.

  According to the invention which concerns on Claim 4, the inside of a rack chamber can be heated entirely. This prevents starting failure of the engine due to freezing of water adhering to the control rack.

  According to the invention which concerns on Claim 5, a control rack can be heated efficiently. This prevents starting failure of the engine due to freezing of water adhering to the control rack.

1 is a side sectional view showing a configuration of a fuel injection pump 1 according to the present invention. The other side surface sectional view showing the composition of fuel injection pump 1 concerning the present invention. The block diagram which shows the control structure of the fuel injection pump 1 which concerns on this invention. The figure showing the graph which shows the relationship between the temperature in the rack room in the fuel injection pump 1 which concerns on this invention, and the state of the water | moisture content contained in blow-by gas. The figure which shows the flowchart showing the control aspect of the fuel injection pump 1 which concerns on this invention. The other side surface sectional view showing the composition of another embodiment of fuel injection pump 1 concerning the present invention.

  Below, the structure of the fuel injection pump 1 which concerns on preferable one Embodiment of this invention is demonstrated using FIGS. 1-3. Note that the present invention includes configurations obtained by combining the configurations shown in the embodiments.

The fuel injection pump 1 supplies fuel to a fuel injection nozzle (not shown) of the diesel engine 40 (see FIG. 3). The fuel injection pump 1 according to this embodiment is a so-called distribution type fuel injection pump 1 that distributes and supplies fuel to each cylinder of the diesel engine 40.
As shown in FIG. 1, the fuel injection pump 1 includes a pump housing 2 and a pump head 3.

  The pump housing 2 is a structure that forms the lower half of the fuel injection pump 1. A cam chamber 4 is formed in the lower part of the pump housing 2. On the upper surface of the pump housing 2, a recess recessed downward in a substantially rectangular parallelepiped shape is formed. In the pump housing 2, a governor flange 2 a for attaching the governor device 24 is formed integrally with the pump housing 2. The pump housing 2 is assembled with a cam shaft 6, a cam 6a, a tappet 8, a bevel gear 10, a transmission shaft 11, and the like.

  The pump head 3 is a structure that forms the upper half of the fuel injection pump 1. The pump head 3 is fixed on the pump housing 2. A space surrounded by the portion of the upper surface of the pump housing 2 forming the depression and the lower surface of the pump head 3 forms a rack chamber 5. The rack chamber 5 is disposed above the cam chamber 4. The pump head 3 is assembled with a plunger 12, a plunger barrel 13, a spring 14, a distribution shaft 15, a sleeve 17, a metering mechanism 18 (see FIG. 2), and the like.

  The cam shaft 6 is a long, substantially cylindrical member that extends horizontally across the cam chamber 4. The cam shaft 6 is rotatably supported by the pump housing 2 via a bearing or the like. A cam 6 a that drives a plunger 12 to be described later is fixed to the middle portion of the cam shaft 6. One end portion of the cam shaft 6 protrudes from the governor flange 2a. A cam gear 7 is fixed to the other end of the cam shaft 6. The cam gear 7 is linked to various gears (not shown) in the gear case 43 of the diesel engine 40. Thereby, the rotational power of the crankshaft (not shown) of the diesel engine 40 is transmitted to the camshaft 6 through various gears accommodated in the gear case 43.

  The tappet 8 is a substantially cylindrical member whose lower end is closed. The tappet 8 is slidably fitted into a tappet hole 2 b formed in the pump housing 2. The tappet hole 2 b is a hole formed so as to communicate the cam chamber 4 and the rack chamber 5 in the vertical direction, and is generally closed by the tappet 8. The tappet 8 is disposed above the cam shaft 6 so that the axial direction thereof is a direction perpendicular to the cam shaft 6. A roller 9 is provided at the lower end of the tappet 8 so as to roll on the cam 6a.

  The transmission shaft 11 is a substantially cylindrical member supported by the pump housing 2. The transmission shaft 11 is disposed above the cam shaft 6 so that the axial direction thereof is perpendicular to the cam shaft 6. The transmission shaft 11 is rotatably fitted in a transmission shaft hole 2 c formed in the pump housing 2. The transmission shaft hole 2 c is a hole formed so as to communicate the cam chamber 4 and the rack chamber 5 in the vertical direction, and is generally closed by the transmission shaft 11. The transmission shaft 11 is linked to the camshaft 6 through bevel gears 10 and 10.

  The plunger 12 pressurizes fuel. The plunger 12 is a substantially cylindrical member and is fitted into a plunger barrel 13 fixed to the pump head 3. A space surrounded by the upper surface of the plunger 12 and the inner peripheral surface of the plunger barrel 13 constitutes a pressurizing chamber 13a. The plunger 12 is disposed above the cam 6 a so that its axial direction is perpendicular to the cam shaft 6. The plunger 12 is configured to be slidable in the axial direction along the inner peripheral surface of the plunger barrel 13 and rotatable in the circumferential direction.

  The tappet 8 is locked to the lower end portion of the plunger 12. Further, a spring 14 that is a compression coil spring is fitted to the lower end portion of the plunger 12. The upper end of the spring 14 is brought into contact with the pump head 3 via the spring receiver 16, and the lower end of the spring 14 is brought into contact with the bottom of the tappet 8. As a result, the tappet 8 is urged downward by the urging force of the spring 14 and is always in contact with the cam 6 a via the roller 9.

  The distribution shaft 15 is a substantially cylindrical member supported by the pump head 3. The distribution shaft 15 is rotatably fitted to a sleeve 17 fixed to the pump head 3. The distribution shaft 15 is disposed above the transmission shaft 11 so that the axial direction thereof is a direction perpendicular to the cam shaft 6. The distribution shaft 15 is linked to the transmission shaft 11.

  As shown in FIG. 2, the metering mechanism 18 is a mechanism for adjusting the amount of fuel supplied from the fuel injection pump 1 to each cylinder of the diesel engine 40. The metering mechanism 18 includes a rack guide 19, a control rack 20, a control sleeve 21, and a glow plug 22.

  The rack guide 19 is a member that supports the control rack 20. The rack guide 19 of this embodiment is fixed to the lower surface of the pump head 3 that is inside the rack chamber 5. The rack guide 19 is formed with a through hole for penetrating the control rack 20.

The control rack 20 is a rod-shaped member. The control rack 20 is inserted into the through hole of the rack guide 19. The control rack 20 can slide in the through hole of the rack guide 19. One end of the control rack 20 is connected to the control sleeve 21, and the middle part of the control rack 20 is connected to a link 30 of a governor device 24 described later via a pin or the like.
Note that the control rack 20 may be colored black in order to be efficiently heated by a glow plug 22 described later.

  The control sleeve 21 is a substantially cylindrical member. The control sleeve 21 is fitted to the plunger 12 while being sandwiched between the plunger 12 and the spring receiver 16. The control sleeve 21 is rotatable in the circumferential direction along the inner peripheral surface of the spring receiver 16. At this time, the plunger 12 rotates integrally with the control sleeve 21 as the control sleeve 21 rotates.

  The glow plug 22 that is a heating means heats the inside of the rack chamber 5. That is, the low plug 22 heats the control rack 20 and the rack guide 19 arranged in the rack chamber 5. The glow plug 22 is inserted into the mounting hole 3 a formed in the pump head 3 from the outside toward the rack chamber 5. The glow plug 22 is fixed to the pump head 3 so that one side end reaches the vicinity of the control rack 20 inside the rack chamber 5. The glow plug 22 is configured such that the other end protrudes from the pump head 3 and can be easily replaced from the outside. The glow plug 22 generates heat at one end when energized.

  As shown in FIG. 3, the control device 23 controls the glow plug 22. The control device 23 stores various programs and data for controlling the glow plug 22. The control device 23 may be configured such that a CPU, a ROM, a RAM, an HDD, and the like are connected by a bus, or may be configured by a one-chip LSI or the like.

  The control device 23 is connected to various devices and sensors of the diesel engine 40. Specifically, the control device 23 is connected to a cooling water temperature sensor 41 that detects the temperature of the cooling water of the diesel engine 40, and can obtain a cooling water temperature signal detected by the cooling water temperature sensor 41. Further, the control device 23 is connected to the power switch 42 of the diesel engine 40 and can acquire an on signal of the power switch 42. The control device 23 is connected to the glow plug 22 and can control on / off of the glow plug 22.

  Next, the governor device 24 attached to the fuel injection pump 1 will be described with reference to FIGS. 1 and 2.

  The governor device 24 is a device for operating the metering mechanism 18. The governor device 24 includes a support member 25, a plurality of centrifugal weights 26, 26,..., A slide body 27, a governor arm 28, a link 30, and a governor housing 29. A governor housing 29 containing these members is attached to the governor flange 2a using bolts or the like.

  The support member 25 is a member that supports the centrifugal weights 26, 26,. The support member 25 is fixed at a position on the inner side of the governor flange 2 a on the cam shaft 6. The support member 25 rotates integrally with the cam shaft 6 as the cam shaft 6 rotates. The support member 25 supports a plurality of centrifugal weights 26, 26,.

  The centrifugal weights 26, 26,... Are weights that slide the slide body 27. One end of each of the plurality of centrifugal weights 26, 26,... Is supported by the support member 25 so as to be separated from the axis of the cam shaft 6. The other ends of the plurality of centrifugal weights 26, 26, are brought into contact with one end of a slide body 27 fitted to the tip portion of the cam shaft 6. When the one end of the centrifugal weights 26, 26,... Moves away from the cam shaft 6, the slide body 27 is pushed out in the axial direction by the other end of the centrifugal weights 26, 26,.

  The slide body 27 is a member that pushes out the governor arm 28. The slide body 27 is brought into contact with one side of a governor arm 28 that is rotatably supported by the governor housing 29. A link 30 is connected to the other side of the governor arm 28. The link 30 is connected to the control rack 20 through a governor communication hole 2d formed in the governor flange 2a.

  Below, the operation | movement aspect of the fuel injection pump 1 comprised in this way is demonstrated.

  When the cam shaft 6 rotates, the tappet 8 in contact with the cam 6a reciprocates in the tappet hole 2b in the vertical direction. Accordingly, the plunger 12 reciprocates up and down in the plunger barrel 13. Thus, the fuel is supplied to the distribution shaft 15 after being sucked and pressurized into the pressurizing chamber 13a.

  The distribution shaft 15 rotates via the bevel gears 10 and 10 and the transmission shaft 11 as the cam shaft 6 rotates. The fuel supplied to the distribution shaft 15 is supplied to the delivery valve 31 by the rotation of the distribution shaft 15. The fuel supplied to the delivery valve 31 is injected from the fuel injection nozzle of each cylinder through an injection pipe (not shown).

  In the governor device 24, the centrifugal weights 26, 26,... Rotating integrally with the cam shaft 6 move the slide body 27 in accordance with the magnitude of the generated centrifugal force. The governor arm 28 is rotated around the support shaft by the movement of the slide body 27. The link 30 is moved by the rotation of the governor arm 28. The control rack 20 is moved in the through hole of the rack guide 19 by the movement of the link 30. As the control rack 20 moves, the control sleeve 21 and the plunger 12 are rotated in the circumferential direction. This makes it possible to adjust the amount of fuel supplied from the fuel injection pump 1 to each cylinder.

  Next, the state of moisture contained in the blow-by gas inside the rack chamber 5 will be described with reference to FIGS.

As shown in FIG. 2, when the diesel engine 40 is started, the internal pressure of the pump housing 2 varies due to the operation of the camshaft 6 and the plunger 12. As a result, air moves between the gear case 43 of the diesel engine 40 and the pump housing 2. Along with this, blow-by gas containing moisture enters the pump housing 2 through the gear case 43.
As shown in FIG. 4, when the temperature inside the rack chamber 5 (the control rack 20) is equal to or lower than the dew point temperature of the blow-by gas, the moisture in the blow-by gas inside the rack chamber 5 is condensed into water droplets. Adhere to 20 mag.

  When the temperature inside the rack chamber 5 exceeds the dew point temperature of the blow-by gas due to the operation of the diesel engine 40, water droplets attached to the control rack 20 and the like evaporate (line A in FIG. 4). When the operation of the diesel engine 40 is stopped and the temperature inside the rack chamber 5 becomes equal to or lower than the dew point temperature of the blow-by gas, moisture in the blow-by gas remaining inside the rack chamber 5 is condensed to the control rack 20 or the like. Adhere as water droplets. When the temperature inside the rack chamber 5 is further lowered to below freezing point, water droplets adhering to the control rack 20 and the like are frozen to become ice droplets.

  On the other hand, if the diesel engine 40 continues to operate in a state where the temperature inside the rack chamber 5 is equal to or lower than the dew point temperature of the blowby gas, moisture contained in the blowby gas that has entered the rack chamber 5 from the diesel engine 40 is condensed. It adheres to the control rack 20 in a superimposed manner (line B in FIG. 4). That is, the amount of water droplets adhering to the control rack 20 increases substantially in proportion to the operating time of the diesel engine 40. When the operation of the diesel engine 40 is stopped and the temperature inside the rack chamber 5 becomes below freezing point, water droplets adhering to the control rack 20 and the like freeze and become ice droplets.

  When the diesel engine 40 is started in a state where the operating environment of the diesel engine 40 is below freezing, the temperature inside the rack chamber 5 is likely to be below freezing. Accordingly, the glow plug 22 is energized for a predetermined time after the power switch 42 of the diesel engine 40 is turned on. One end of the glow plug 22 generates heat (see the black arrow in FIG. 2), and heats the inside of the rack chamber 5. After the predetermined time has elapsed, the control rack 20 is operated to start the diesel engine 40.

  Below, the operation | movement aspect of the control apparatus 23 in the fuel injection pump 1 comprised as mentioned above using FIG. 3 and FIG. 5 is demonstrated.

  As shown in FIG. 3, the control device 23 acquires the coolant temperature signal of the diesel engine 40 from the coolant temperature sensor 41 when the input signal from the power switch 42 is acquired. The control device 23 controls on / off of the glow plug 22 based on the acquired signal.

  As shown in FIG. 5, the control device 23 controls on / off of the glow plug 22 in the following steps.

  First, in step S <b> 101, the control device 23 acquires an on signal from the power switch 42 connected to the control device 23.

  In step S <b> 102, the control device 23 acquires a coolant temperature signal from the coolant temperature sensor 41 connected to the control device 23.

In step S103, the control device 23 determines whether or not the temperature T of the cooling water is lower than the reference temperature Tt from the temperature signal of the cooling water from the cooling water temperature sensor 41. That is, based on the temperature T of rejected water, it is determined whether or not there is a high possibility that water droplets attached to the control rack 20 inside the rack chamber 5 are frozen.
As a result, when it is determined that the temperature T is lower than the reference temperature Tt, that is, the water droplets adhering to the control rack 20 inside the rack chamber 5 may be frozen based on the temperature T of the reject water. When it determines with it being high, the control apparatus 23 makes a step transfer to step S104.
On the other hand, when it is determined that the temperature T is not lower than the reference temperature Tt, that is, there is a possibility that water droplets adhering to the control rack 20 inside the rack chamber 5 are frozen based on the temperature T of the reject water. When it determines with not being high, the control apparatus 23 makes a step transfer to step S204.

  In step S <b> 104, the control device 23 turns on the glow plug 22. That is, the control device 23 melts the ice droplets attached to the control rack 20 by the glow plug 22. Thereafter, the control device 23 shifts the step to step S105.

In step S105, the control device 23 determines whether or not a predetermined time has elapsed for the glow plug 22 to enter. This predetermined time is set to a time sufficient to melt ice drops frozen by overheating by the glow plug 22.
As a result, when it is determined that the glow plug 22 has entered the predetermined time, the control device 23 shifts the step to step S106.
On the other hand, if it is determined that the glow plug 22 has not entered the predetermined time, the control device 23 returns the step to step S105.

  In step S <b> 106, the control device 23 turns off the glow plug 22 and starts the diesel engine 40.

  In step S204, the control device 23 starts the diesel engine 40.

  The above is description about the operation | movement aspect of the fuel injection pump 1 which concerns on this embodiment. The technical idea of the present invention is not limited to the application to the diesel engine 40 and the fuel injection pump 1 described above, but can be applied to an engine and a fuel injection pump having other configurations.

  In addition, as shown in FIG. 6, as another embodiment of the present embodiment, there is a fuel injection pump 1 that uses a plate heater 32 instead of the glow plug 22 that is a heating means.

  A plate heater 32 as a heating means heats the inside of the rack chamber 5. That is, the low plug 22 heats the control rack 20 and the rack guide 19 arranged in the rack chamber 5. The plate heater 32 is fixed to the inner wall of the rack chamber 5. The plate heater 32 is arranged so that one side surface faces the control rack 20 inside the rack chamber 5. When energized, one side of the plate heater 32 generates heat (see the black arrow in FIG. 6), and heats the control rack 20 inside the rack chamber 5 as a whole.

As described above, in the fuel injection pump 1 according to the first embodiment of the present invention, the control rack 20 that adjusts the fuel injection amount is arranged inside the rack chamber 5 formed by the pump head 3 and the pump housing 2. The fuel injection pump 1 of the diesel engine 40 is provided with a glow plug 22 that is a heating means for heating the rack chamber 5 and the control rack 20.
With this configuration, even if water is frozen and ice droplets are generated inside the rack chamber 5, the glow plug 22 can dissolve them. Thereby, the starting failure of the diesel engine 40 by the water | moisture content adhering to the control rack 20 freezing is prevented.

The fuel injection pump 1 according to the first embodiment of the present invention further includes a control device 23. When the diesel engine 40 is powered on and the cooling water temperature T is equal to or lower than the reference temperature Tt, the fuel injection pump 1 according to the first embodiment The heating of the plug 22 is started, and the heating is finished after a predetermined time has elapsed.
With this configuration, the interior of the rack chamber 5 is heated when there is a possibility that moisture will freeze inside the rack chamber 5. Thereby, the starting failure of the diesel engine 40 by the water | moisture content adhering to the control rack 20 freezing is prevented.

The glow plug 22 is detachably provided on the pump head 3.
With this configuration, the glow plug 22 can be easily provided inside the rack chamber 5. Moreover, even if the glow plug 22 breaks down, it can be easily replaced. Thereby, the starting failure of the diesel engine 40 by the water | moisture content adhering to the control rack 20 freezing is prevented.

A plate heater is provided instead of the glow plug 22 and is provided on the inner wall of the rack chamber 5.
By comprising in this way, the inside of the rack chamber 5 can be heated entirely. Thereby, the starting failure of the diesel engine 40 by the water | moisture content adhering to the control rack 20 freezing is prevented.

The control rack 20 is colored black.
By comprising in this way, the control rack 20 can be heated efficiently. Thereby, the starting failure of the diesel engine 40 by the water | moisture content adhering to the control rack 20 freezing is prevented.

1 Fuel Injection Pump 2 Pump Housing 3 Pump Head 5 Rack Room 20 Control Rack 22 Glow Plug

Claims (5)

A fuel injection pump for an engine in which a control rack for adjusting a fuel injection amount is arranged inside a rack chamber formed by a pump head and a pump housing,
A fuel injection pump provided with heating means for heating the rack chamber and the control rack. A control device;
2. The fuel injection pump according to claim 1, wherein when the engine coolant is turned on and a cooling water temperature of the engine is equal to or lower than a predetermined temperature, heating of the heating unit is started and the heating is ended after a predetermined time has elapsed. The heating means includes
The fuel injection pump according to claim 1, wherein the fuel injection pump is constituted by a glow plug and is detachably provided on the pump head. The heating means includes
The fuel injection pump according to claim 1 or 2, comprising a plate heater and provided on an inner wall of the rack chamber.   The fuel injection pump according to claim 3 or 4, wherein the control rack is colored black.

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