JPH05195899A - Distributor type fuel injection pump - Google Patents

Abstract

PURPOSE:To provide an overflow distributor type fuel injection pump in which detection accuracy of fuel temperature is improved by fitting a temperature detecting sensor on the position where temperature similar to the temperature of fuel sucked into a pump pressurized chamber can be detected. CONSTITUTION:A spill solenoid valve 16 is provided in an overflow passage communicating together a pressurized chamber to pressurize fuel with a plunger and a low pressure chamber. A fuel temperature sensor 72 is provided on the way of the passage communicating from the low pressure chamber to the pressurized chamber through a suction passage 74 and a suction port 73. The fitting tool 76 of the fuel temperature sensor 72 is fitted to the position opposite to the suction port 73 of a pump housing 11, and a sensor main body 76 is fitted inside the fitting tool 76. Thereby, the temperature of fuel on the part position near by fuel to be injected is detected, and exact compensation of a fuel injection quantity can be performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distribution type fuel injection pump used in a diesel engine or the like, and more particularly to an overflow distribution type fuel injection pump equipped with a fuel temperature sensor for detecting the temperature of fuel. It is about.

[0002]

2. Description of the Related Art Conventionally, Japanese Utility Model Publication No. 60-3953 discloses an electronically controlled fuel injection device that corrects the fuel injection amount according to the temperature of the fuel of a distributed fuel injection pump. In this system, the arithmetic processing unit of the control device corrects the fuel injection amount according to the output of the fuel temperature sensor that detects the temperature of the fuel of the fuel injection pump, and compensates the fuel injection amount.

[0003]

It is desirable that the portion for detecting the fuel temperature used for correcting or compensating for the fuel injection amount is as close as possible to the position immediately before being sucked into the injection pump pressurizing chamber. However, according to such a conventional distributed fuel injection pump, since the mounting position of the fuel temperature sensor is mounted on the upper portion of the pump casing, there is a slight difference in the temperature of the fuel at each site in the pump chamber, The temperature difference between the detected temperature of the fuel and the temperature of the actual injected fuel may be large.

Generally, in a distribution type injection pump using this type of spill ring, a fuel cut solenoid valve for stopping the supply of fuel is attached to the side of the plunger pressurizing chamber, so that the plunger pressurizing chamber is It is difficult to install the fuel temperature sensor near the. The problem to be solved by the present invention is to make it possible to mount a temperature detection sensor at a position where the temperature close to the temperature of the fuel sucked into the pump pressurizing chamber can be detected, and to improve the detection accuracy of the fuel temperature. A flow type distributed fuel injection pump.

Another problem to be solved by the present invention is to provide an overflow distribution which enables optimum fuel injection control by compensating the fuel temperature and improves output performance, exhaust performance, noise characteristics, fuel consumption characteristics and the like. Type fuel injection pump.

[0006]

An overflow distribution type fuel injection pump according to the present invention for solving the above problems is a distribution type fuel injection in which fuel is pumped and distributed by reciprocating motion of a plunger and rotational motion of a distributing member. In the pump, a first passage connecting the pressurizing chamber by the plunger and the low pressure chamber,
A spill solenoid valve that is provided in the first passage and opens the first passage at the end of fuel injection; a second passage that communicates the pressurizing chamber by the plunger with the low pressure chamber;
And a fuel temperature sensor provided at a portion facing the suction port communicating with the pressurizing chamber.

[0007]

Since the temperature of the fuel is detected immediately before the fuel sucked into the pump pressurizing chamber formed by the cylinder and the plunger, the fuel temperature that is closest to the temperature of the fuel pumped from the pump is obtained. Can be detected.

[0008]

Embodiments of the present invention will now be described with reference to the drawings. 1 to 4 show a schematic structure of a face cam type distribution type fuel injection pump showing an embodiment of the present invention. As shown in FIG. 3, the distributed fuel injection pump 1 takes in the fuel pumped up from the fuel tank to the pump low pressure side passage by the feed pump 2 into the gallery (fuel low pressure chamber) 5 through the pump high pressure side passage, and High-pressure fuel whose injection amount is adjusted as described later is pressure-fed from the delivery valve 7 to the injection nozzle of the diesel engine.

The inside of the fuel injection pump 1 is a cylindrical cylinder 12 built in a pump housing 11, and a plunger 36 and a plunger 36 which are rotatably fitted to the inner peripheral surface of the cylinder 12 to switch the fuel passage. It is composed of a spill solenoid valve 16 and the like for causing the fuel pressurized at 2 to overflow from the pressurizing chamber 13 via the overflow passage 23. Cylinder 12
In the interior of the pressurizing chamber 13 from the gallery 5 via the communication passage.
2 for supplying fuel to the delivery port, a discharge passage 22 for pumping the fuel pressurized in the pressurizing chamber 13 to the delivery valve 7 via the distribution passage 24, and adjusting the fuel injection amount. In order to do so, overflow passages 23 for releasing the fuel from the pressurizing chamber 13 to the gallery 5 are provided respectively, and these passages 22 and 23 are respectively opened to the outer peripheral surface of the plunger 36 sliding on the cylinder inner peripheral wall surface 12a. ing.

In the plunger 36 for distributing the fuel, the distribution port 24 for distributing the fuel supplied to the pressurizing chamber 13 to the discharge passage 22 corresponding to each delivery valve 7, the pressurizing chamber 13
The high-pressure fuel pressurized by the discharge port 2 from the distribution port 24
Discharge ports 32 for discharging to 2 are provided respectively. Drive shaft 1 by rotation of diesel engine
When 7 is rotated, plunger 36 moves face cam 40
Reciprocally moving in the axial direction along the cam profile of No. 1 and the intake stroke for sucking fuel from the gallery 5 to the pressurizing chamber 13 via the intake passage 74 and the intake port 73, and from the pressurizing chamber 13 to the distribution port. 24, discharge port 32, discharge passage 2
The pressure feeding process of delivering high-pressure fuel from the delivery valve 7 to the nozzle via 2 is repeated, and in synchronization with this, the spill solenoid valve 16 is opened to overflow from the pressurizing chamber 13 via the overflow passage 23. The fuel overflow timing is adjusted, that is, the fuel injection amount is controlled.

As shown in FIGS. 1 and 2, a fuel temperature sensor 72 is attached to the pump housing 11. In FIG. 2, an intake port 73 for supplying fuel to the pressurizing chamber 13 of the plunger 36 is opened in the cylinder 12, and the intake port 73 is provided in the pump housing 1.
1 is connected to the suction passage 74. The fuel temperature sensor 72 detects the temperature of the fuel in the chamber 75 formed in the middle of the suction passage 74. This fuel temperature sensor 72
Is attached to the pump housing 11 via an O-ring 77, the sensor body 79 is housed inside the attachment 76, and the sensor body 79 is tightened and fixed by an attachment screw 81 via an O-ring 78. . The fixture 76 is attached to the pump housing 11 so that the fuel temperature detection portion of the sensor body 79 faces the suction port 73.

Therefore, there is an effect that the temperature value of the fuel closest to the temperature of the fuel sucked into the pressurizing chamber 13 is detected. Further, the mounting position of the fuel temperature sensor 72 is a position where it does not become a resistance of the fuel flow with respect to the fuel intake. Generally, in a VE type fuel injection pump in which fuel is metered by a spill ring, a fuel cut valve required when fuel supply is stopped is attached to a portion corresponding to the attachment position of the fuel temperature sensor 72 of the above embodiment. Although it is impossible to attach the fuel temperature sensor of the sensor to this portion due to the structure of the pump, in the injection pump which is metered by the overflow type spill solenoid valve as in the above-mentioned embodiment, the fuel as described above is used. A temperature sensor can be attached.

The fuel temperature signal detected by the fuel temperature sensor 72 is used for compensating the fuel injection amount. For example, by compensating for the decrease in the actual fuel injection amount due to the rise in the fuel temperature with the electronic control unit, it is possible to prevent the output performance from decreasing, and through programming, exhaust performance, noise characteristics,
It is possible to set an optimum fuel injection amount for fuel consumption characteristics and the like.

[0014]

As described above, according to the distributed fuel injection pump of the present invention, since the fuel temperature sensor is attached to the position facing the intake port immediately before the pressurizing chamber by the plunger, fuel injection is performed. There is an effect that the temperature of the fuel in a portion close to the fuel is detected, and thereby the fuel injection amount can be appropriately compensated by accurately detecting the fuel temperature.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view showing a distributed fuel injection pump according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a sectional view showing a distributed fuel injection pump according to a first embodiment of the present invention.

FIG. 4 is a side view showing a distributed fuel injection pump according to a first embodiment of the present invention.

[Explanation of symbols]

 5 Gallery (Low Pressure Chamber) 16 Spill Solenoid Valve 23 Overflow Passage (First Passage) 36 Plunger (Distribution Member) 72 Fuel Temperature Sensor 73 Intake Port 74 Intake Passage (Second Passage) 75 Chamber (Second Passage)

Claims (1)

[Claims] 1. A distribution type fuel injection pump for pumping and distributing fuel by reciprocating motion of a plunger and rotational motion of a distribution member, wherein a first passage communicating a pressure chamber by a plunger and a low pressure chamber, and the first passage. Is installed in the passage of the
The spill solenoid valve that opens the passage of the second passage, the second passage that communicates the pressure chamber by the plunger with the low pressure chamber, and the suction port that communicates with the pressure chamber in the middle of the second passage. A distribution-type fuel injection pump, comprising: a fuel temperature sensor provided at a facing portion.