JPH0893590A - Fuel injection pump - Google Patents

Abstract

PURPOSE: To reduce nitrogen oxides, carbon monoxide and black smoke in exhaust gas by, when an engine turns into a fixed operating state, opening a switch valve for supplying water through a water supply hole to fuel in a through hole. CONSTITUTION: A plunger 14 moves vertically in the through hole 13a of a plunger barrel 13 fitted in a pump housing 12 to forcedly feed fuel to a fuel injection nozzle. A fuel chamber 16 is formed between the upper outer peripheral face of the plunger barrel 13 and the inner peripheral face of the pump housing 12, and the fuel chamber 16 is made to communicate with the through hole 13a through an intake-exhaust hole 13b formed in the upper part of the peripheral wall 13d of the plunger barrel 13. A water supply hole 13c being smaller in bore than the intake-exhaust hole 13b is formed in the upper part of the peripheral wall 13d of the plunger barrel 13 being upper as far as a fixed distance than the intake-exhaust hole 13b, and a water pressure-feed means 17 is connected to the water supply hole 13c through a switch valve 22. When an engine turns into a fixed operating state, the switch valve 22 opens to supply water through a water supply hole 13c to the fuel 15 in the through hole 13a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection pump for injecting fuel into an engine.

[0002]

2. Description of the Related Art Conventionally, a turbocharger having a water supply means for supplying water to a combustion chamber of an engine is formed by an injection means provided for each cylinder, and the injection means has a water injection directed to a suction port of the cylinder. Type internal combustion engine is disclosed (JP-A-60-73036). In this internal combustion engine, the injection means is formed by a water injection valve, and the injection valve is continuously controlled by the controller based on the load and rotation speed of the engine. In the internal combustion engine configured as described above, by injecting water into the cylinder to suppress the exhaust gas temperature to a low level, the knocking tendency can be overcome, and a high charge pressure and a high power output can be obtained.

[0003]

However, in the conventional turbocharger type internal combustion engine equipped with water injection, water is injected into the cylinder separately from the fuel, so that the water is not uniformly mixed with the fuel. As a result, in diesel engines that use light oil as a fuel, the mixing of fuel and air is not promoted so much that the fuel does not completely burn in the cylinder, and the emission of carbon monoxide and black smoke is reduced. There was room for improvement.

The object of the present invention is to provide nitrogen oxides in exhaust gas,
It is to provide a fuel injection pump capable of reducing carbon monoxide and black smoke.

[0005]

A configuration of the present invention for achieving the above object will be described with reference to FIG. 1 corresponding to an embodiment. The present invention relates to a plunger barrel 13 inserted into a pump housing 12 and having a through hole 13a, and a through hole 13
a plunger 14 that moves up and down in a to pump the fuel 15 to the fuel injection nozzle, a fuel chamber 16 formed between the upper outer peripheral surface of the plunger barrel 13 and the inner peripheral surface of the pump housing 12, and the plunger barrel 13 This is an improvement of the fuel injection pump including an intake / exhaust hole 13b which is formed in the upper part of the peripheral wall 13d and which communicates the fuel chamber 16 and the through hole 13a. Its characteristic structure is that the intake / exhaust holes 13b.
A water supply hole 13c having a diameter smaller than that of the intake / exhaust hole 13b is formed in the upper part of the peripheral wall 13d of the plunger barrel 13 located a predetermined distance above, and the water pressure supply means 17 is connected to the water supply hole 13c via the opening / closing valve 22 to operate the engine. When the predetermined operating state is reached, the on-off valve 22 is opened to supply water from the water supply hole 13c to the fuel 15 in the through hole 13a.

[0006]

When the engine is in a predetermined operating state such as when the engine is under a heavy load, the opening / closing valve 22 is opened and the water pressurized by the water pressure feeding means 17 is discharged while the water supply hole 13c is not closed by the plunger 14. The fuel 15 in the through hole 13a is supplied from the water supply hole 13c. The fuel 15 containing water is injected into the cylinder of the engine through the fuel injection nozzle and burns. The combustion temperature in the cylinder is kept relatively low by containing water, and the water in the fuel 15 promotes mixing of the fuel 15 injected into the cylinder and the air, whereby the fuel is completely burned.

[0007]

An embodiment of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, a row-type fuel injection pump 11 for injecting fuel into an engine includes a pump housing 12
Plunger barrel 13 inserted into this barrel, and this barrel 13
And a plunger 14 that is vertically movable.
A through hole 13a is formed along the axis of the plunger barrel 13, and the plunger 14 is vertically movably inserted into the through hole 13a. Although not shown, the lower end of the plunger 14 contacts a cam via a roller tappet. A fuel chamber 16 is formed between the upper outer peripheral surface of the plunger barrel 13 and the inner peripheral surface of the pump housing 12, and an intake / exhaust hole 13b is formed in the upper portion of the peripheral wall 13d of the plunger barrel 13. The fuel chamber 16 and the through hole 13a communicate with each other through the intake / exhaust hole 13b.

The characteristic structure of this embodiment is that the intake / exhaust hole 13b is provided.
A water supply hole 13c having a diameter smaller than that of the intake / exhaust hole 13b is formed in the upper part of the peripheral wall 13d of the plunger barrel 13 located a predetermined distance above, and the water pressure supply means 17 is connected to the water supply hole 13c via the opening / closing valve 22 to operate the engine. When the load becomes high, the on-off valve 22 is opened to supply water from the water supply hole 13c to the fuel 15 in the through hole 13a.
The water pressure feeding means 17 includes a water tank 18 in which water is stored, a water supply pipe 19 connecting the water supply hole 13c and the water tank 18,
The water in the water tank 18 provided in the water supply pipe 19
3c and the water pump 21 which pressure-feeds.

The water supply hole 13c is formed from the inside of the peripheral wall 13d of the plunger barrel 13 to the flange portion 1 at the upper end of the barrel 13.
3e, and a second passage 32 provided between the lower wall 23a of the element holder 23 interposed between the upper part of the pump housing 12 and the upper part of the plunger barrel 13 to the peripheral wall 23b. It is connected to the water supply pipe 19 via. First and second passages 31, 32
Is formed by closing unnecessary portions of the perforations after the perforation processing. The opening / closing valve 22 is a 3-port / 2-position switching solenoid valve provided in the water supply pipe 19 downstream of the water pump 21. When the opening / closing valve 22 is turned on, the water pumped by the water pump 21 is supplied to the water supply hole 13c, and when it is turned off, the water pumped by the water pump 21 returns to the water tank 18 through the overflow pipe 25. There is. Reference numeral 24 is a check valve that prevents water from flowing back to the water pump 21 from the water supply hole 13c. Although not shown, water supply holes are also formed in other through holes of the pump 11,
These water supply holes are connected by a branch pipe branched from the water supply pipe 19 on the downstream side of the check valve.

Although not shown, the crankshaft of the engine is provided with a rotation sensor for detecting the rotation speed of the engine, and the accelerator pedal is provided with a load sensor for detecting the load of the engine based on the depression amount. The temperatures of the engine oil and the engine cooling water are respectively detected by the oil temperature sensor and the cooling water temperature sensor, and the water amount in the water tank 18 is detected by the float type level sensor. Each detection output of the rotation sensor, the load sensor, the oil temperature sensor, the cooling water temperature sensor, and the level sensor is connected to the control input of the controller (not shown), and the control output of the controller is connected to the water pump 21 and the opening / closing valve 22. It The on-off valve 22 is turned on when the engine is idling, except when the engine is operating under light and medium loads, that is, when the engine is under heavy load. However, even when the engine is under heavy load, there is no water in the water tank 18 When the temperature of the engine cooling water is lower than that of the engine cooling water or when the temperature of the engine cooling water is lower than a predetermined temperature, the power is not turned on.

A delivery valve holder 26 is screwed into the element holder 23, and a delivery valve seat 27 that abuts against the upper surface of the plunger barrel 13 is provided in the lower part of the delivery valve holder 26. The sheet 27 has a through hole 27a communicating with the through hole 13a.
A delivery valve 28 is inserted in 7a so as to be vertically movable. Although not shown, the upper end of the delivery valve holder 26 is connected to the feed hole of the fuel injection nozzle via a delivery pipe, and the fuel 15 leaked at the fuel injection nozzle is fed to the fuel chamber 16 of the fuel injection pump 11 or the feed through the return pipe. It is designed to return to the pump.

The operation of the fuel injection pump configured as described above will be described. When the engine (not shown) is started in a state where a predetermined amount of water or more is stored in the water tank 18, the controller (not shown) operates the water pump 21 based on the detection output of the level sensor. Since the controller keeps the on-off valve 22 off based on the detection outputs of the rotation sensor, the load sensor, the oil temperature sensor, and the cooling water temperature sensor (not shown) when the engine is idling and operating under light and medium load, the water in the water tank 18 is It is not supplied to the water supply hole 13c and returns to the water tank 18 via the overflow pipe 25.

When the oil temperature sensor and the cooling water temperature sensor respectively detect that the temperatures of the engine oil and the engine cooling water have exceeded a predetermined value, respectively, and when the load sensor detects that the engine has a high load, The controller turns on the opening / closing valve 22 based on each detection output of these sensors, and while the water supply hole 13c is not closed by the plunger 14, the water pressurized by the water pressure feeding means 17 is discharged from the water supply hole 13c. Fuel 15 in through hole 13a
Is supplied to.

With the on-off valve 22 turned on, the plunger 1
Immediately after 4 moves down and the water supply hole 13a is opened, the water pressurized by the water pressure-feeding means 17 is relatively vigorously supplied into the fuel 15 in the through hole 13a. Is relatively well mixed. When the plunger 14 starts to rise, the pressure of the fuel 15 containing water in the through hole 13a becomes larger than the pressure of the water pressurized by the water pressure feeding means 17, so that the supply of water to the fuel 15 is stopped, Fuel of 15
The amount of water supplied to the water supply hole 13a is small because the hole diameter of the water supply hole 13a is smaller than that of the water suction hole 13b. Further, the fuel 15 mixed with water is generated in the fuel 15 containing water in a period from when the plunger 14 moves up and the intake / exhaust hole 13b is closed by the plunger 14 to when the water supply hole 13c is closed by the plunger 14. Through hole 13a, fuel chamber 1
6 and the flow in the water supply hole 13c, the water is further mixed with the fuel 15. The fuel 15 containing water is pressure-fed to a fuel injection nozzle (not shown), and is injected into a cylinder (not shown) of the engine from an injection hole at the lower end of the nozzle to burn. At this time, the combustion temperature in the cylinder is suppressed to a relatively low level by containing water, so that the emission of nitrogen oxides can be reduced. Further, the water in the fuel 15 promotes the mixing of the fuel 15 injected into the cylinder with the air, and the fuel 15 is completely burned, so that the emission of carbon monoxide and black smoke can be reduced.

[0015]

As described above, according to the present invention, a water supply hole having a smaller diameter than the intake / exhaust hole is formed in the upper part of the peripheral wall of the plunger barrel a predetermined distance above the intake / exhaust hole, and the water supply hole has an opening / closing valve. The water pumping means is connected via the water supply means, and when the engine is in a predetermined operating state, the on-off valve is opened so that water can be supplied from the water supply hole to the fuel in the through hole. In this state, the on-off valve opens, water is supplied from the water supply hole to the fuel in the through hole, and the fuel containing this water is further injected into the cylinder of the engine through the fuel injection nozzle and burned. As a result, the combustion temperature in the cylinder can be suppressed to a relatively low level by containing water, so that the emission of nitrogen oxides can be reduced. Further, since the water in the fuel promotes the mixing between the fuel injected into the cylinder and the air, the fuel is completely burned, so that the emission of carbon monoxide and black smoke can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a fuel injection pump including a water pressure feed unit according to an embodiment of the present invention.

[Explanation of symbols]

 11 Fuel Injection Pump 12 Pump Housing 13 Plunger Barrel 13a Through Hole 13b Suction / Discharge Hole 13c Water Supply Hole 13d Plunger Barrel Wall 14 Plunger 15 Fuel 16 Fuel Chamber 17 Water Pumping Means

Claims (1)

[Claims] 1. A through hole inserted into a pump housing (12).
A plunger barrel (13) having (13a) and the through hole (13
a) between the plunger (14) that moves up and down inside to pump the fuel (15) to the fuel injection nozzle, and the upper outer peripheral surface of the plunger barrel (13) and the inner peripheral surface of the pump housing (12). A fuel chamber (16) formed, and an intake / exhaust hole (13b) formed on the peripheral wall (13d) of the plunger barrel (13) and connecting the fuel chamber (16) and the through hole (13a). In the fuel injection pump, a water supply hole (13c) having a diameter smaller than that of the intake / exhaust hole (13b) is formed in the upper part of the peripheral wall (13d) of the plunger barrel (13) above the intake / exhaust hole (13b) by a predetermined distance. , A water pressure feed means (1) to the water supply hole (13c) through an on-off valve (22).
(7) is connected, and the on-off valve (2
A fuel injection pump characterized in that the water can be supplied to the fuel (15) in the through hole (13a) from the water supply hole (13c) by opening 2).