JPS6128047Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a fuel injection pump.

In a compression ignition engine, under high load (when the excess air ratio is small), the air-fuel mixture is incompletely formed, resulting in poor combustion, worsening exhaust smoke, and increased fuel efficiency.
In order to improve this, it is possible to reduce the amount of fuel supplied, but if the amount of fuel is reduced, the momentum will decrease due to a decrease in the injection mass, and as a result, the mixing state with air will also deteriorate.

In view of the above, the present invention was proposed for the purpose of achieving an appropriate fuel supply state without reducing the injection mass. a plurality of main pumps that supply the main fuel in the pressurizing chambers; an auxiliary liquid inlet that is provided in each of the fuel pressurizing chambers and opens and closes according to the operating state of each corresponding main pump;
A supply passage whose one end communicates with the discharge side of the sub-pump that supplies an auxiliary liquid with a lower calorific value than the main fuel, and which branches in the middle and whose other ends communicate with each of the auxiliary liquid inlets, and the auxiliary pump. a liquid passage for supplying the auxiliary liquid from the auxiliary liquid tank, and an on-off valve that opens and closes the liquid passage depending on the operating state of the engine, and when each of the auxiliary liquid intake ports is opened by the action of the on-off valve. The auxiliary liquid is supplied from the auxiliary pump to each corresponding fuel pressurizing chamber, and the auxiliary liquid is mixed with the main fuel and supplied to the plurality of combustion chambers. The gist of this invention is a fuel injection pump characterized by:

An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, main pumps 2a, 2b, and 2c are arranged in a row in a casing (not shown) installed in a multi-cylinder compression ignition engine for an automobile. The fuel pressurizing chamber 8 is formed by a plunger 6 that is slidably and rotatably fitted into the fuel pressurizing chamber 8. The fuel pressurizing chamber 8 communicates with a fuel tank 10 containing light oil, which is the main fuel, through a main fuel inlet 12, and also communicates with the compression ignition through a discharge port 16 in which a discharge valve 14 is installed. It communicates with a fuel injection nozzle (not shown) provided in one of the combustion chambers of the engine. Further, the fuel pressurizing chamber 8 is provided with an auxiliary liquid suction port 19 at a position facing the main fuel suction port 12, which communicates with a sub pump 24, which will be described later, through a supply hole 17. 18 is a spiral groove provided to control the discharge port of the plunger 6, and the plunger 6 is slidably moved by a pump cam 20 driven by the engine and rotated by a governor device 22 to control the discharge amount. be done. and fuel tank 1
The light oil sent from 0 to the fuel pressurizing chamber 8 is pressurized by the action of the plunger 6 and is forcedly sent to the fuel injection nozzle. Further, other main pumps 2b and 2c arranged in a row within the casing have the same configuration as the main pump 2, and each supply main fuel to the other combustion chambers of the compression ignition engine. ing. And these main pumps 2a, 2
b and 2c are designed to be injected at different times due to the phase difference in the lift of each pump cam, and each of the pump cams has a lift part 204 on most of the base circle 202, as represented by the pump cam 20. are formed so that the suction ports 19 do not open at the same time. On the other hand, the sub pump 24
A pressurizing chamber 30 is formed by a barrel 26 and a plunger 28 that is slidably and rotatably fitted into the barrel 26. Water is supplied to the pressurizing chamber 30 from the tank 32 via the suction port 34 of the auxiliary pump 24, and the water supplied to the pressurizing chamber 30 is passed through a discharge port 38 provided with a discharge valve 36 and a supply passage. 40 to each fuel pressurizing chamber of each main pump. By the way, one end of the supply passage 40 communicates with the discharge port 38, and the supply passage 40 branches in the middle so that the other end communicates with each supply hole of each main pump. Reference numeral 42 denotes a spiral groove provided to control the discharge amount of the plunger 28. The plunger 28 is slidably moved by a pump cam 44 driven by the engine, and rotated by the output of the governor device 22. and the discharge amount is controlled. At this time, the pump cam 44 has three congruent parts spaced at equal intervals on the base circle 442.
As shown in FIG. 2, the sub pump 24 discharges water when the auxiliary liquid suction port 19 of each main pump 2a, 2b, 2c is opened. ing.
In addition, a well-known feed pump 52 and a solenoid valve 54 for stopping the main fuel supply are disposed in the fuel passage 50 between the fuel tank 10 and the main fuel intake port 12. liquid passage 5
6 is provided with a feed pump 58 and a solenoid valve 60 as described above, and this solenoid valve 60 is configured to close the liquid passage 56 when the engine is started, that is, when a starter motor (not shown) is driven.

According to the above configuration, when the engine is started, the solenoid valve 60 serving as an on-off valve closes the liquid passage 56, so only light oil, which is the main fuel, is supplied to the fuel pressurizing chambers of the main pumps 2a, 2b, and 2c. Only the main fuel is injected into each combustion chamber. On the other hand, during normal operation, the solenoid valve 60 opens the liquid passage 56, so that water guided into the pressurizing chamber 30 flows through the plunger 28.
The auxiliary liquid inlet 12 is opened by this action, and the fuel is alternately supplied to the fuel pressurizing chambers of the main pumps 2a, 2b, 2c, mixed with the main fuel, and injected into each combustion chamber. By the way, the amount of water injected changes as shown in FIG. 3 out of the total amount of injection set by the governor device 22 which is linked with the accelerator pedal.

Therefore, it is possible to prevent excessive fuel supply while ensuring a sufficient amount of injection into each combustion chamber during high loads, thereby achieving a good mixing state of air and fuel, and reducing exhaust smoke and fuel consumption. This has the effect of measuring improvement. Moreover, in that case, multiple main pumps 2
Since one sub pump 24 is used for the sub pumps 2a, 2b, and 2c, it is inexpensive, and the auxiliary liquid suction ports 19 of the main pumps 2a, 2b, and 2c that communicate with the sub pumps 24 do not open at the same time. , and the same amount of water is pumped out from the sub pumps 24 in synchronization with the opening of each auxiliary liquid suction port 19 by the action of the pump cam 44 having a common lift part, so that each main pump 2a , 2b, 2c, the amount of water occupying each fuel pressurizing chamber is approximately equal,
Accordingly, the amount of light oil in each fuel pressurizing chamber becomes approximately equal, and fuel having the same calorific value is supplied to each combustion chamber, making it possible to prevent engine torque fluctuations. In the above embodiment, one sub pump 24 was operated for three main pumps 2a, 2b, 2c, but the number of main pumps to which water is supplied from one sub pump is arbitrary.

Furthermore, in the above embodiment, the pump cam for driving the sub-pumps is provided with the same number of lift parts as the number of main pumps, and the discharge timing of the sub-pumps is set, so that the same amount of water is supplied to each main pump with a different injection timing. However, this configuration may be replaced with a configuration in which the number of lift parts of the pump cam for driving the sub-pump is reduced and, as an alternative, the rotation speed of the pump cam is increased relative to the rotation speed of the main pump cam. For example, if the number of main pumps communicating with one sub-pump is three, the pump cam for driving the sub-pump should have one lift, and the rotation speed of the pump cam should be three times the rotation speed of the pump cam for driving the main pump. And it is sufficient.

Furthermore, in the above embodiment, water is used as the liquid with a lower calorific value than the main fuel, but this liquid may be a flammable substance with a lower calorific value such as alcohol.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram showing an embodiment of the present invention;
FIG. 2 is an explanatory diagram of the operation of each pump in the same embodiment, and FIG. 3 is an injection characteristic diagram of the main pump in the same embodiment. 2a, 2b, 2c...Main pump, 8...Fuel pressurization chamber, 10...Fuel tank, 19...Auxiliary liquid inlet, 20...Pump cam, 22...Governor device, 24...Sub-pump, 40 ...Supply passage, 44
...Pump cam.

Claims (1)

[Scope of utility model registration request] A plurality of main pumps supplying main fuel in each fuel pressurizing chamber to a plurality of combustion chambers of a multi-cylinder compression ignition engine, each of which is provided in each fuel pressurizing chamber and depending on the operating state of each corresponding main pump. An auxiliary liquid inlet that opens and closes, one end of which communicates with the discharge side of an auxiliary pump that supplies an auxiliary liquid with a lower calorific value than the main fuel, and branches in the middle, with the other end communicating with each of the auxiliary liquid inlets. A supply passageway for supplying the auxiliary liquid from the auxiliary liquid tank to the auxiliary pump, and an on-off valve that opens and closes the liquid passage according to the operating condition of the engine, and each of the auxiliary liquid fuels is supplied by the action of the on-off valve. When the suction port is open, the auxiliary liquid is supplied from the auxiliary pump to each corresponding fuel pressurizing chamber, and the auxiliary liquid is mixed into the main fuel and supplied to the plurality of combustion chambers. A fuel injection pump characterized in that the fuel injection pump is configured to be supplied with fuel.