JPS5925040A - Fuel supply control device - Google Patents

Abstract

PURPOSE:To control fuel supply with a high accuracy by a simple mechanism, by moving a control rack by means of a linear motor. CONSTITUTION:An injection pump 2 is designed in such that respective pump units 6 control the amount of fuel to be supplied at one time according to stroke of a control rack 8. As the control rack 8 is directly moved by a linear step motor 9, a rectilinear motion obtained by the linear motor 9 may be directly utilized, thus eliminating a link mechanism for converting a rotary motion to a rectilinear motion. As a result, structure may be simplified, and since the linear motor 9 is disposed in such that teeth 18 are positioned opposed to coils 20 in a non-contact manner, it is possible to provide a control device which hardly fails to work and has a high reliability. Further, since the linear motor 9 is constituted of a step motor, the coil 20 of the motor may be directly controlled by a control signal from a microcomputer 10, wherein the control signal from the microcomputer 10 is not required to be converted to an analog signal.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel supply control device, and more particularly to a device that controls the amount of fuel supplied by moving a control rack provided on a fuel injection pump.

A diesel engine is equipped with a fuel injection pump that sequentially supplies fuel to each cylinder of the engine. The amount of fuel supplied by the fuel injection pump is controlled by moving the control rack of the fuel injection pump via a mechanical governor attached to the fuel injection pump using a load lever that is linked to the accelerator pedal. It was being done. Controlling the amount of fuel supplied by a fuel injection pump using a conventional mechanical governor is inferior in accuracy and cannot perform various complex controls such as economical driving or constant speed driving. Therefore, the engine has the disadvantage of not being able to fully demonstrate its functions.

In order to overcome these drawbacks, attempts have been made to control the supply of fuel using an electronic control device such as a microcomputer. In carrying out such control, control signals from the electronic control device are used to move the control rank of the fuel injection pump via various actuators. However, when driving a control rack using, for example, a normal motor as an actuator, rotational motion must be converted into linear motion, which complicates the mechanism and increases the risk of wear and tear on the sliding parts. This has the disadvantage of decreasing reliability. In addition, when using both electronic control and mechanical governor control and selectively using both, the control
This has the disadvantage that the coupling mechanism between the actuator and the control rack becomes more complicated.

The present invention has been made in view of these problems, and it is an object of the present invention to provide a device that controls the amount of fuel supplied with high precision using a simple mechanism.

An embodiment in which the present invention is applied to a fuel supply control device for a vehicle diesel engine will be described below with reference to the drawings.

As shown in FIG. 1, a fuel injection pump 2 is attached to the side of a diesel engine 1. This fuel injection pump 2 is a cam that is rotated by the rotation of the engine 1 via a gear 3 and a timer 4. It is designed to be driven by a cam fixed to the shaft 5. That is, the fuel injection pump 2 has the same number of cylinders as the engine 1, for example, six pump units 6, and these pump units 6 are driven by respective cams provided on the camshaft 5 to supply fuel. Fuel is sequentially supplied into the cylinders of the engine 1 via a pipe 7.

The fuel injection pump 2 also includes a control rack 8, which controls the amount of fuel supplied by each pump unit 6 at one time. The control rack 8 is attached to the casing of the fuel injection pump 2, and its stroke is controlled by a near motor 9. Control signals are supplied to the linear motor 9 from the microcomputer 1o. The microcomputer 10 receives a detection output from a sensor 12 that detects the amount of depression of the accelerator pedal 11, a detection output from a rotation detection sensor 13 that detects the number of revolutions of the engine 1, and a position detection sensor that detects the position of the rack 8. Detection outputs from 14 are respectively input. Although not shown here, the microcomputer 10 is further provided with information such as the gear ratio of the transmission, the running speed of the vehicle, a signal for setting the running state, the state of the clutch, whether or not the brake is operating, the outside temperature, and the engine cooling. Various information such as water temperature and engine oil temperature is input.

Next, to explain the structure of the linear motor 9, the second
As shown in FIG. 3 and FIG. 3, the control rack 8 that controls the amount of fuel supplied at one time by each pump unit 6 of the fuel injection pump 2 has a pinion 16 fixed to the barrel 15 of each pump unit 6. are meshed with each other. A plunger 17 is arranged inside the barrel 15 so as to be slidable in the vertical direction. On the opposite side of the control rack 8 from the surface on which the teeth that mesh with the pinion 16 are formed, a large number of other teeth 18 are installed in a line, as shown in FIG. . Inside the convex portion 19 of the casing of the pump 2, facing these teeth 18, a large number of coils are similarly arranged in a line via support means (not shown).

These coils and teeth 18 constitute a linear step motor 9, and the relationship between them is particularly shown in an enlarged manner in FIG. 4.As is clear from this figure,
The pitch of the arrangement of the teeth 18 and the pitch of the arrangement of the coil additions are different from each other, and the coil additions are arranged at a pitch 7 larger than the pitch of the teeth 18. That is, for example, if the pitch of the tooth J8 arrangement is 1 mm, the pitch of the coil addition arrangement is 1.25 mm. Therefore, by switching the excitation of the coil between adjacent coils,
The rack 8 to which the teeth 18 are attached will move in steps by a length of 7 of the pitch of the arrangement of the teeth 18.

That is, in the above example, if only one coil is switched to excite, the rack 8 will move by 0125 mm.

In the above configuration, microcomputer-0
Therefore, by selecting the energized coil of the linear motor 9 consisting of a step motor, this coil is energized and generates an attractive force, which causes the control rack 8 to be energized via the teeth 18. will be moved. That is, by shifting the exciting coil one by one to the right or left in FIG. 4, the control rack 8 will be moved to the right or left by one length of the pitch of the arrangement of the teeth 18. . When the control rack 8 is moved to the left in FIG. 3, the amount of fuel supplied increases in order to rotate the barrel 15 via the pinion 16, and the rack 8 is also moved to the right. In this case, since the barrel 15 is rotated in the opposite direction by the pinion 16, the amount of fuel supplied is reduced. In this way, the amount of fuel supplied at one time by each pump unit 6 of the fuel injection pump 2 is controlled by the linear motor 9 and the control rack 8 based on the control signal from the microcomputer 0. Become.

As described above, according to the fuel supply control device of this embodiment, since the control rack 8 is directly moved by the linear step motor 9, the linear motion obtained by the linear motor 9 can be directly utilized. This eliminates the need for a link mechanism or the like that converts rotational motion into linear motion. This simplifies the structure, and since the teeth 18 and the coils of the linear motor 9 are in contact with each other in a non-contact manner, it is possible to provide a highly reliable control device with fewer failures. In addition, in the control device of this embodiment, since the control rack 8 is controlled by the non-contact linear motor 9, if the power supply to the coil of the linear motor 9 is stopped, the control rack 8 can be freely operated. It becomes possible to move to. Therefore, in combination with a conventional mechanical governor, it becomes possible to freely select control by the governor or control by the near motor 9.

Furthermore, according to the control device of this embodiment, since the control rack 8 is designed to support the teeth 18 of the linear motor 9, the control rack 8 constitutes the movable element of the linear motor. 1 linear motor 9
The driving force is directly transmitted to the control rack 8, and troubles such as stiffness do not occur. Furthermore, since the linear motor 9 is constituted by a step motor, the coil application of this motor can be directly controlled by the control signal from the microcomputer-0. There is no need to convert it to an analog signal.

Next, a modification of the above embodiment will be explained with reference to FIGS. 5 and 6. In this modification, parts corresponding to those in the above embodiment are given the same reference numerals, and descriptions of parts having the same structure will be omitted. In this modification, on the casing side of the fuel injection pump 2, a coil d is provided below the coil, which is shifted by one length of the pitch of the teeth 18, and the width of the teeth 18 is It was designed to be larger. In such an arrangement, by alternately energizing the adjacent coils, the rack 8 is moved by one length of the pitch of the teeth 18. In other words, in this modification, the rack 8 can be arranged with twice the accuracy of the arrangement shown in FIG. 4 above.
This makes it possible to drive. Therefore, for example tooth 18
If the pitch of the arrangement of the coils is 1 mm, and the pitch of the arrangement of the coils and d is 1.25 mm, then by switching the coil application and d, the rack 8 will move in steps of %125 mm. Become.

Although the present invention has been described above with reference to the embodiments and modified examples, the present invention is not limited to the above embodiments and modified examples, and various changes can be made based on the technical idea of the present invention. For example, in the first embodiment shown in FIGS. 3 and 4 above, each coil is wound around a separate core, but as shown in FIG. 7, coils of the same phase are grouped together. Then, they may be wound around a common iron core 21, and the tip of this iron core may be formed with ζζ unevenness. According to such a configuration, the winding work of adding the coil can be easily performed. Further, in the above embodiment, the teeth 18 are attached to the control rack 8, but the teeth may be formed by attaching magnets to the rack 8, or by forming unevenness and magnetizing the unevenness. It may also be used as a movable element of the linear motor 9. In addition, by using 1-2 phase excitation as the method of excitation of the coil excitation or gear in the above embodiments and modified examples, it is possible to further double the accuracy of the movement of the rack 8, thereby improving control efficiency. Resolution can be improved.

As described above, according to the present invention, since the control rack is moved by a linear motor, there is no need for a mechanism for converting rotational motion into linear motion. In addition, the structure is simpler and the control rack can be moved without contact.
Failures are reduced and reliability is improved. In addition, since the control rack is driven by a non-contact linear motor, the control rack can move freely if the power supply to the linear motor is stopped, making it extremely difficult to use or combine it with a governor. It will be done easily.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view showing a fuel supply control device for a diesel engine according to an embodiment of the present invention, FIG. 2 is a front view of a fuel injection pump installed in which engine, and FIG.
The figure is an enlarged cross-sectional view of the lines ■ to ■ in Figure 2. Figure 4 is the 3rd
FIG. 5 is an enlarged plan view of a linear motor according to a modified example, FIG. 6 is a front view showing the arrangement of coils of this modified linear motor, and FIG. 7 is another modified example. FIG. 3 is a plan view of an example linear motor. In addition, in the symbols used in the drawings, 2...Fuel injection pump 8...Control rack 9...
・・・・ Linear motor 18 ・・・・・・・・・・−・−・−・− Coil with teeth 20.

Claims (1)

[Claims] 1. A device for controlling the amount of fuel supplied by moving a control rack provided on a fuel injection pump, characterized in that the control rack is moved by a linear motor. fuel supply control device. 2. The fuel supply control device according to claim 1, wherein the linear motor is a step motor. 3. The fuel supply control device according to claim 1 or 2, wherein the control rack constitutes a movable element of the linear motor.