JPH10165U - Fuel injection control device - Google Patents

Abstract

(57) [Summary] [Purpose] To improve the electrical reliability and to improve the assembly workability without losing the versatility of the governor housing. [Constitution] 7 mm from the end face of the connector part of the wire harness
The electric wires 22 are exposed. Five of these wires 2
Numeral 2 is drawn into the governor chamber through the harness connection port of the governor housing, and is soldered to a terminal provided on a wiring board of the electric governor. The remaining two electric wires 22 are connected to the connector end face 2 in the harness connection port.
It is directly connected to the thermistor 30 arranged near 1a.

Description

[Detailed description of the invention]

[0001]

[Industrial applications]

 The present invention relates to a fuel injection control device that electrically controls a fuel injection amount, a fuel injection timing, and the like.

[0002]

[Prior art]

 As disclosed in Japanese Unexamined Patent Publication No. 1-159427, a fuel injection control device used for a diesel engine or the like uses a variety of sensors to detect physical changes such as engine speed, load, and fuel temperature. Based on this data, the fuel injection pump is electrically controlled in accordance with the control program stored in the memory of the microcomputer, and optimal fuel injection conditions (such as fuel injection amount and fuel injection timing) are determined. There is something to do. In a fuel injection pump controlled by this type of fuel injection control device, a so-called electric governor in which a control sleeve for changing a fuel injection amount is controlled by an electromagnetic actuator is used.

In general, a fuel injection pump has a characteristic that the fuel injection amount decreases as the fuel temperature increases, even if the position of the control sleeve is set at the same position. This is caused mechanically by the fact that the viscosity of the fuel decreases as the fuel temperature increases. Therefore, in the fuel injection control device, the position of the control sleeve is corrected according to the fuel temperature at that time, and control is performed so as to obtain a desired optimum fuel injection amount.

[0004] The above-mentioned fuel temperature is often detected from the fuel filled in a governor chamber containing an electric governor. In that case, conventionally, a temperature sensor unit having a temperature sensing element such as a thermistor was prepared, and this was attached to a governor housing, as if an ignition plug was attached to a cylinder head. However, in this structure, the head of the temperature sensor unit protrudes from the governor housing, and the height of the fuel injection pump is correspondingly increased, which requires a large installation space, which is disadvantageous. In addition, the temperature sensor unit, which is an independent single component, is expensive and costs up.

[0005] To solve the problem, as disclosed in Japanese Patent Application Laid-Open No. 62-162752, a device has been developed in which a temperature-sensitive element for detecting fuel temperature is embedded in a connector portion of a wire harness. However, such a structure causes a problem that the detection sensitivity is deteriorated because the fuel does not directly contact the temperature sensing element. The wire harness electrically connects the electric governor and the control unit.The connector is connected to a connection port provided in the governor housing, and the electric wire of the wire harness is connected to the governor chamber from the connection port. It is retracted and connected to the electric governor.

In order to improve the detection sensitivity, the present applicant has installed a temperature sensing element for fuel temperature detection on a wiring board of an electric governor housed in the governor chamber, and provided the temperature sensing element in the governor chamber. Devised a structure that can directly touch the fuel.

[0007]

[Problems to be solved by the invention]

 With the above-described structure, two terminals for the temperature sensing element are required. As a result, the number of terminals provided on the wiring board is increased by two compared with the conventional case. By the way, these terminals are generally arranged in a line at the end of the wiring board corresponding to the connection port of the governor housing in consideration of workability when connecting to the wires of the wire harness. It is. Correspondingly, the wires exposed from the end face of the connector portion of the wire harness are generally arranged in a line on the end face.

Here, when trying to use a governor housing which has been used conventionally, the connection port of the governor housing is necessary for arranging the number of terminals in a line when there is no terminal for the temperature sensing element. Since the dimensions are set to the minimum, the gap between the terminals becomes very narrow even if the number of terminals for the temperature sensing element is increased by two, and there is a risk of short-circuiting if the terminals are left bare. . In order to prevent this, a new insulation measure must be taken, and the structure becomes complicated, and it takes time and effort, leading to an increase in cost.

In addition, corresponding to the terminals, the wires exposed from the end face of the connector portion of the wire harness are also densely arranged. As described above, it is very difficult to perform connection work in a state where terminals and electric wires are densely arranged, and there is a problem that workability is poor. On the other hand, if a governor housing having a large connection port corresponding to the number of terminals is prepared, the governor housing becomes less versatile, leading to increased costs and disadvantageous. The present invention has been made in view of the above-mentioned problems of the conventional technology, and its purpose is to provide a governor housing that is not only versatile but also electrically reliable and has a simple structure. Another object of the present invention is to provide a fuel injection control device with good assembling work.

[0010]

[Means for Solving the Problems]

 This invention has been made to achieve the above-mentioned object, and the gist of the invention is that an electric governor that controls a control sleeve for changing a fuel injection amount of a fuel injection pump is provided in a governor chamber provided inside the governor housing. The electric governor is provided with a temperature sensing element for detecting the fuel temperature in order to correct the fuel injection condition according to the fuel temperature, while the harness connection port provided in the governor housing has: A fuel injection control device in which the connector part of the wire harness that electrically connects the electric governor and the control unit is connected, and the electric governor is electrically connected to the electric wire exposed from the end face of the connector part facing the harness connection port. In the above, the temperature-sensitive element is connected to the connector in the harness connection port. Of the end face is arranged near, in the fuel injection control apparatus characterized by being connected to the wires exposed from the end face.

[0011]

[Action]

 Since the temperature sensing element was placed near the end face of the connector part of the wire harness inside the harness connection port and this temperature sensing element was connected to the electric wire exposed from the connector part, the wiring board of the electric governor was used for the temperature sensing element. Terminals are not required. Therefore, the number of terminals on the wiring board may be the same as the number of terminals when the above-described conventional temperature sensor unit is used or when no temperature-sensitive element is provided. Also, among the wires exposed from the end face of the connector part of the wire harness, the number of wires that need to be connected to the terminals of the wiring board through the connection port of the governor housing also depends on whether the temperature sensor unit is used or the temperature sensitive element is used. The same number of wires would be required if not.

[0012] Accordingly, the size of the connection port of the governor housing is sufficient as the size of the connection port provided in the conventional governor housing, and the conventional governor housing can be used as it is, and versatility is improved. In addition, the dimensions between the terminals can be made sufficient and the insulation between the terminals can be secured. Further, workability in connecting the terminal and the electric wire is improved. Further, since the fuel comes into direct contact with the temperature sensing element, the detection sensitivity is good.

[0013]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS. FIG. 3 is a view showing a main part of the fuel injection control device, and is a view of a governor housing in which an electric governor is accommodated as viewed from above. FIG. 1 is a sectional view taken along line II of FIG. However, in FIG. 1, the electric governor is omitted for convenience of illustration.

The electric governor 1 includes an electromagnetic actuator unit (not shown) for operating a control sleeve of the fuel injection pump, and a position sensor unit 2 for electrically detecting the position of the control sleeve. The electric governor 1 is housed in a governor chamber 11 formed inside a governor housing 10 with the electromagnetic actuator unit facing downward and the position sensor unit 2 facing upward. The governor housing 10 is attached so as to close an upper opening (both not shown) of a pump housing of the fuel injection pump, and projects a lower projecting portion 10a of the governor housing 10 into the pump housing. . A cover (not shown) is attached to the upper side of the governor housing 10.

The position sensor unit 2 of the electric governor 1 has a wiring board 3. The wiring board 3 is provided with five wiring boards 4, 4,..., Each of which is electrically connected to a drive system of an electromagnetic actuator and a position detection system of a control sleeve. Then, one end of each wiring board 4 is raised to form a terminal 4a, which is collected at a corner (lower right portion in FIG. 3) of the wiring board 3 so that the insulation between the terminals 4a is sufficiently high. They are arranged side by side at predetermined intervals so as to be secured.

On the other hand, the governor housing 10 has a harness receiving portion 12 formed on one side thereof, and a harness connection port 13 is formed through the center of the harness receiving portion 12. The harness connection port 13 is provided at a position corresponding to the terminals 4a arranged on the wiring board 3 of the electric governor 1 in an assembled state. FIG. 4 is a front view of the governor housing 10. As shown in FIG. 4, the harness connection port 13 has a horizontally long shape, and its horizontal dimensions are arranged in a row in the wiring board 3. The width is slightly larger than the width of the group of terminals 4a.

A connector portion 21 of a wire harness 20 for electrically connecting the electric governor 1 and a control unit (not shown) is fixed to the harness receiving portion 12. FIG. 2 is a front view of the connector portion 21 as viewed from the direction of arrow A in FIG. 1. As shown in FIG. 2, seven portions 21 b of the end surface 21 a of the connector portion 21 face the harness connection port 12. The electric wires 22, 22 are exposed. Five of these wires 22 are arranged in a substantially arc shape at the same pitch as the pitch of the terminals 4a at equal intervals, are drawn into the governor chamber 11 of the governor housing 10 through the harness connection port 13, and are shown in FIG. As described above, and soldered to the corresponding terminals 4a.

The remaining two electric wires 22 of the seven electric wires 22 are arranged at positions facing the five electric wires 22. These two electric wires 22 are directly connected to a thermistor (temperature sensing element) 30 for detecting the fuel temperature, which is disposed slightly apart from the end face 21 a on the harness connection port 13 side in the harness connection port 13. I have.

In the fuel injection control device having the above-described configuration, the thermistor 30 is directly connected to the electric wire 22 exposed from the wire harness 20, so that the wiring board 3 does not require a terminal for the thermistor. Therefore, the number of terminals 4a provided on the wiring board 3 may be the same as the number of terminals in the case where a temperature sensor unit is used or the case where no temperature sensing element is provided in the related art. The number of 22 may be the same as in the conventional case. As a result, when the distance between the terminals 4a and the distance between the electric wires 22 to be inserted into the harness connection port 13 are set to the same dimensions as those of the related art, the size of the harness connection port 13 of the governor housing 10 is also reduced. Since the size of the governor housing 10 can be the same, a conventional product can be used for the governor housing 10 itself. Further, since the thermistor 30 is exposed and comes into direct contact with the fuel, the detection sensitivity of the fuel temperature is very good.

The present invention is not limited to the above embodiment, and various modes can be adopted. For example, the temperature-sensitive element is not limited to the thermistor, but may be various kinds of temperature-sensitive semiconductors or temperature-sensitive reactance elements.

[0021]

[Effect of the invention]

 As described above, according to the present invention, the temperature sensing element is disposed in the harness connection port near the end face of the connector portion of the wire harness, and the temperature sensing element is connected to the electric wire exposed from the connector portion. In addition, the wiring board of the electric governor does not require terminals for the temperature sensing element. The excellent effect that the governor housing can be used is exhibited.

Further, since the dimensions between the terminals can be made the same as the conventional dimensions, the insulation between the terminals can be sufficiently ensured, and the fuel temperature can be detected directly by the fuel being in direct contact with the temperature-sensitive element, thereby improving the fuel temperature detection sensitivity. As a result, an excellent effect of improving the electrical characteristics of the fuel injection control device is achieved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a governor housing according to the present invention, showing a state in which a wire harness is mounted, and FIG.
FIG.

FIG. 2 is an end view of a connector portion of the wire harness as viewed from a direction of an arrow A in FIG. 1;

FIG. 3 is a plan view of the governor housing in a state where an electric governor is housed in the governor chamber.

FIG. 4 is a front view of the governor housing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric governor 10 Governor housing 11 Governor room 13 Harness connection port 20 Wire harness 21 Connector part 21a End face 22 Electric wire 30 Thermistor (thermosensor)

Continuing from the front page (72) Inventor Kinji Mayuzumi 3-13-26, Yayumicho, Higashimatsuyama-shi, Saitama Prefecture Inside of Xexel Higashi-Matsuyama Plant (72) Inventor Tohru Yokota 3-13-26, Yayumicho, Higashimatsuyama-shi, Saitama Prefecture Zexel Higashimatsuyama Plant

Claims (1)

[Utility model registration claims] An electric governor for controlling a control sleeve for changing a fuel injection amount of a fuel injection pump is housed in a governor chamber provided inside a governor housing, and the electric governor is configured to perform fuel injection according to a fuel temperature. A temperature sensing element for fuel temperature detection is provided to correct the condition.On the other hand, a harness connection port provided in the governor housing has a wire harness for electrically connecting the electric governor and the control unit. In a fuel injection control device in which an electric governor is electrically connected to an electric wire exposed from an end face of the connector portion facing the harness connection port, the temperature-sensitive element is connected to the connector portion in the harness connection port. Near the end face of the wire, and is connected to the electric wire exposed from the end face. The fuel injection control apparatus characterized by being.