JPS62240465A - Fuel injection pump - Google Patents

Abstract

PURPOSE:To correctly detect the standard timing of the pump operation free from the influence of abrasion of a various sorts of constitution parts and working precision by installing a pulser for obtaining the standard revolution position information of a cam disc so as to revolve integrally with the cam disc. CONSTITUTION:In a distribution type fuel injection pump 1, a plunger 4 fitted into a plunger barrel 3 fixed onto a housing 2 is revolved by the cooperative action of a roller holder 7 and a cam disc 6 revolved by a driving shaft 5 and pressurizes the fuel inhaled into a high pressure chamber 8. The pump 1 is equipped with the first and second signal generators 20 and 30 in order to obtain the signals related to the operation timing, i.e., the angular position and standard revolution position of the cam disc 6. In this case, the shaft 11 of a pulser 31 in the second signal generator 30 is integrally connected with the cam disc 6 by a connecting pin 13. Therefore, the phase deflection between the pulser 31 and the cam disc 6 can be suppressed by the integral revolution of the both.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fuel injection pump equipped with a timing detection device capable of accurately detecting reference timing of operation of a distribution type fuel injection pump.

(Prior Art) In a distribution type fuel injection pump, a configuration in which the fuel injection amount and/or injection timing, etc. are electronically controlled is known. If so, it is necessary to electrically detect the operating timing of the fuel injection pump. For this reason, in the past, as shown in Japanese Patent Laid-Open No. 60-125756, for example, a pulsar is attached to the drive shaft of a distribution type fuel injection pump, and a pickup coil is disposed near the pulsar. A fuel injection pump configured to obtain a signal indicating the rotational angular position of the cam disk and a signal indicating the reference angular position of the cam disk by electrically detecting the timing at which a cog provided in the cam disk faces a pickup coil. is widely used.

(Problem to be Solved by the Invention) However, when detecting the operating timing of the fuel injection pump using a pulser attached to the drive shaft of the distribution type fuel injection pump, the accuracy of the detection timing is different from that of the drive shaft. It depends on the mechanical wear and/or machining accuracy of the coupling provided between the roller holder and the roller holder. Therefore, there is a particular problem in that it is difficult to accurately detect the reference timing of the operation of the fuel injection pump over a long period of time.

An object of the present invention is to accurately maintain the required reference timing of a distribution type fuel injection pump over a long period of time, regardless of the wear and/or machining accuracy of various mechanical parts interposed between the drive shaft and the plunger. An object of the present invention is to provide a fuel injection pump that can be detected.

(Means for Solving the Problems) The content of the present invention for achieving the above object is that in a distribution type fuel injection pump, a pulser for obtaining reference rotational position information of a cam disk is connected to a cam disk and a plunger spring. The pulsar is disposed between the cam disk and the cam disk, and the pulsar is characterized in that it is configured to rotate together with the cam disk.

(Function) Since the pulser for obtaining reference rotational position information rotates together with the cam disk, the required reference timing of the fuel injection pump can be accurately set regardless of the accuracy and wear of the mechanical parts between the drive shaft and the plunger. It becomes possible to detect

(Example) Hereinafter, the present invention will be explained in detail with reference to illustrated embodiments.

FIG. 1 shows an embodiment of a distributed fuel injection pump according to the present invention. The distribution type fuel injection pump 1 includes a plunger barrel 3 fixed to a housing 2, and a plunger 4 fitted into the plunger barrel 3 so as to be movable in the axial direction, and is driven by an internal combustion engine (not shown). Due to the cooperative action of the cam disc 6 rotated by the drive shaft 5 and the roller holder 7,
The plunger 4 rotates and reciprocates in accordance with the rotation of the drive shaft 5, and pressurizes the fuel sucked into a high pressure chamber 8 formed within the plunger barrel 3.

This pressurized fuel is taken out via an oil passage 10 that is opened and closed by a spill valve 9, and is force-fed to a fuel injection valve attached to a cylinder of an internal combustion engine (not shown). The fuel pumping operation of the above-mentioned distribution type fuel injection pump that uses a spill valve to control the fuel injection amount is the same as that of the conventional distribution type fuel injection pump, so the details will not be explained here. omit doing that.

In order to obtain signals related to the actuation timing of the distribution fuel injection pump 1, that is, the angular position and the reference rotational position of the cam disc 6, respectively, the distribution fuel injection pump 1 has first and second signal generators 20 and 30. It is equipped with

The first signal generator 20 is for extracting a rotation angle signal S indicating that the cam disc 6 has rotated by a predetermined angle, and is connected to a gear 21 fixed to the drive shaft 5 and a frame 7a of the roller holder 7. It consists of a first pick-up coil 22 which is screwed on. 1st pick up coil 2
2, when the gear 21 rotates together with the drive shaft 5, the teeth of the gear 21 touch the detection end 22 of the first pickup coil 22.
a, and each time the drive shaft 5 rotates by a predetermined angle θ, an electric pulse signal is output from the first pickup coil 22, and a signal composed of this electric pulse signal is a rotation angle signal S. .

is output as

The second signal generator 30 is for taking out a reference position signal S2 indicating that the cam disc 6 has reached a desired reference rotational position, and is composed of a pulser 31 and a second pickup coil 32.

In FIG. 2, the pulsar 31 is shown in detail.

The distribution type fuel injection pump 1 shown in FIG. 1 is for six cylinders, and therefore, cogs 31a to 31'' are formed on the outer peripheral edge of the pulser 31 at intervals of 60 degrees.

At the center of the pulser 31, there is a mounting hole 34 having a diameter 33.
is formed, and this mounting hole 34 is fitted into the stepped portion 11a of the shaft 11 provided at one end of the plunger 4, and the key? A key 12 provided on the stepped portion 11a is fitted into R33, and as a result, the pulser 31 rotates together with the shaft 11. The shaft 11 is configured to rotate together with the cam disk 6 by means of a connecting pin 13 embedded in the cam disk 6, and therefore, the pulser 31 is configured to eventually rotate together with the cam disk 6. A spring seat 14 is also fitted into the stepped portion 11a of the shaft 11, and the spring seat 14 is pressed toward the pulser 31 by a plunger spring 15.

A bearing washer 16 is disposed between the spring seat 14 and the pulsar 31. Therefore, the spring seat 14 is pressed against the pulsar 31 via the bearing washer 16, so that the spring seat 14 prevents the rotation of the pulsar 31. will not hinder.

The second pick amplifier coil 32 is screwed and fixed to a mounting bracket 35 bolted to the frame 7a of the roller holder 7 so that its detection end 32a faces the pulser 31, and the pulser 31 rotates. When the detection end 3
2a faces each cog 31a to 31f of the pulser 31 in sequence. As can be seen from the above description, each timing at which each of the cogs 31a to 31f faces the detection end 32a occurs when the cam disc 6 reaches a predetermined reference rotational position (for example, each rotational position at which the plunger 4 starts lifting). This is adjusted to match the timing, so that every time the cam disc 6 reaches a predetermined reference position, an electric pulse signal indicating this is output, and a pulse signal consisting of this electric pulse signal becomes the reference position signal S2. is output as

The rotation angle signal S1 and the reference position signal S2 are input to the control unit l-(C/U) 40 together with the accelerator signal A indicating the operation amount of the accelerator pedal (not shown), and here, these input signals are The required control calculations based on the
The optimal fuel injection timing and fuel injection amount are calculated according to the current operating conditions. The control unit 40 is
An opening/closing control signal Cs is output for controlling the opening/closing of the spill valve 9 so that the fuel injection timing and fuel injection amount are obtained based on these calculation results, and the spill valve 9 is operated in response to this opening/closing control signal Cs. However, control of fuel injection timing and fuel injection amount is thereby performed electronically.

According to the above configuration, the pulsar 3 of the second signal generator 30
1 rotates together with the cam disc 6, so the pulsar 31
The phase shift between the drive shaft 5 and the cam profile can be kept extremely small, and the phase will not shift due to machining accuracy or wear of various parts installed between the drive shaft 5 and the cam disc 6. 6 reaches the required reference position can be detected with extremely high accuracy over a long period of time.

Furthermore, since the second pick-up coil 32 is fixed to the frame 7a of the roller holder 7 by the mounting bracket 35, when the roller holder 7 is repeatedly operated by the timer 50 for reasons such as adjusting the injection timing, the second pick-up coil 32 is fixed to the frame 7a of the roller holder 7. Since the second pickup coil 32 also moves, the timing of the required reference angular position can be detected accurately without being affected by the adjustment of the timer 50.

(Effects) According to the present invention, as described above, since the pulser for detecting the reference timing of the operation of the fuel injection pump is rotated together with the cam disk, each The accuracy of the required detection timing is not affected by the dimensional accuracy of parts, wear, etc., and highly accurate timing detection can be performed over a long period of time.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing essential parts of an embodiment of a distribution type fuel injection pump according to the present invention, and FIG. 2 is a front view of the pulser shown in FIG. 1. l...distribution type fuel injection pump, 4...plunger,
5... Drive shaft, 6... Cam disc, 7... Roller holder, 7a... Frame, 14... Spring seat, 20... First signal generator, 30... Second Signal generator, 31...Pulser, 32...Second pickup coil, S2...Reference position signal.

Claims (1)

[Claims] 1. In the distribution type fuel injection pump, a pulser for obtaining reference rotational position information of the cam disc is disposed between the cam disc and the plunger spring seat so as to rotate together with the cam disc. Features a fuel injection pump.