JPH0310361Y2 - - Google Patents

Description

[Detailed explanation of the idea]

[Industrial Application Field] The present invention relates to an injection timing detection device for a distribution type fuel injection pump, and is particularly suitable for use in a solenoid valve spill type distribution type fuel injection pump of a diesel engine. a conversion member for converting the reciprocating motion of the fuel pumping plunger into a reciprocating motion of the fuel pumping plunger; and a timing control for controlling the fuel injection timing by rotationally displacing the conversion member within the pump housing relative to the drive shaft. The present invention relates to an injection timing detection device for a distribution type fuel injection pump having means.

[Prior art]

As shown in Japanese Patent Publication No. 51-34936, one of the distribution type fuel injection pumps used in diesel engines has a so-called so-called so-called so-called so-called so-called so-called so-called fuel injection pump in which the end of the fuel pumping is controlled by a solenoid valve instead of a spill ring. A solenoid valve spill type distribution fuel injection pump is known. For example, as shown in FIGS. 1 and 2,
A roller ring 16 for converting the rotational motion of the drive shaft 12 driven by the engine output shaft into a reciprocating motion of the plunger 14 for pumping fuel, a roller 18 housed in the roller ring 16, and the drive shaft 12. A converting member consisting of a cam plate 20 having a cam surface on which the roller 18 rolls is connected to the converting member so as to be freely movable only in the axial direction, and the roller ring 16 is attached to the drive shaft 12 within the pump housing 22. and timing control means consisting of a timer piston 24 and a slide pin 26 that transmits the movement of the timer piston 24 to the roller ring 16 for controlling the fuel injection timing by rotationally displacing the timer piston 24 relative to the roller ring 16. ing. In the figure, 30 is a feed pump rotationally driven by the drive shaft 12, which is shown rotated by 90 degrees on the left side of FIG. A compression spring for engaging with the cam plate 20, 34 a plunger chamber formed on the tip side of the plunger 14, 36 a suction passage for sucking fuel into the plunger chamber 34, and 38 a plunger chamber. A distribution passage for distributing the high-pressure fuel compressed in the plunger chamber 3 to injection nozzles arranged in each cylinder of the diesel engine via the delivery valve 40;
This solenoid controls the injection end timing by opening a spill port 44 provided on the wall of the pump 4 at the end of fuel pumping, thereby controlling the fuel injection amount. In such an electromagnetic valve spill type distribution type fuel injection pump 10, the right end of the plunger 14 is connected to the plunger chamber 34, and presses down the plunger chamber 34 in conjunction with the cam surface of the cam plate 20. This plunger chamber 34 is connected to the spill port 4.
4 is connected to the solenoid 42. Therefore,
A timing control valve (not shown) is controlled by an external electronic control device, and thereby the position of the timer piston 24, that is, the rotational displacement of the roller ring 16 is set at a predetermined position, so that the plunger 14 is lifted. The start timing, that is, the fuel injection timing can be controlled. Further, by changing the activation timing of the solenoid 42 using an external electronic control device, the end timing of injection of high-pressure fuel in the plunger chamber 34, that is, the fuel injection amount can be changed. In such a solenoid valve spill type distributed fuel injection pump 10, the conventional method for detecting the advance angle of the injection timing is as shown in FIG. 2 above.
A timer position sensor 50 is provided in series with the timer piston 24, and the timer position sensor 50 detects the displacement of the timer piston 24, thereby detecting the advance angle of the injection timing.
However, since the timer position sensor 50 needs to linearly detect the stroke of the timer piston 24 without contact, it has a complicated structure.
Moreover, it requires an electronic circuit, which is expensive.
In addition, there was a problem in that the reliability was not very high. On the other hand, as a method for controlling the operation of the solenoid 42, for example, a reference position sensor that detects that the rotational displacement of the drive shaft 12 is at a reference position is provided, and the plunger 14 is at the reference position, for example, when it is under compression. It is conceivable to detect a certain time before the opening, and after an appropriate delay time has elapsed from this certain time, an output signal is output from the electronic control device to the solenoid 42 to operate the solenoid 42. However, in a fuel injection pump having a timing control means including a timer piston 24 as shown in FIGS. 1 and 2, the displacement of the timer piston 24 causes the roller ring 16 to
Since the rotational displacement of the plunger 14 changes, and the operating position of the plunger 14 also changes, there have been cases where an appropriate amount of fuel injection cannot be obtained. In order to solve these problems, for example, as disclosed in Japanese Patent Application Laid-Open No. 55-54642, and also proposed by the applicant in Japanese Patent Application Laid-Open No. 59-221432, which was published after the filing of the present application, the roller ring 16 is It is conceivable to provide a sensor for detecting the start of injection and operate the solenoid 42 after an appropriate delay time after the output of the injection start sensor is generated, but this injection start sensor alone cannot determine the injection timing. Since the advance angle could not be detected, it was necessary to use the timer position sensor 50 in combination.

[Purpose of invention]

The present invention was made to solve the above-mentioned conventional problems, and it is possible to easily and accurately detect the advance angle of the injection timing with respect to the engine reference position without using a stroke-type timer position sensor. An object of the present invention is to provide an injection timing detection device for a distribution type fuel injection pump.

[Structure of the idea]

The present invention consists of a rotor and a cam member that rotate in synchronization with the rotation of the drive shaft, a rotatable roller ring that rotatably supports a roller that rolls on the surface of the cam member, and an engine that uses reciprocating motion. a fuel pumping plunger for pumping fuel, the cam member and the roller obtain reciprocating motion of the fuel pumping plunger from the rotational movement of the drive shaft, and the rotation of the roller ring causes the cam member and the roller to rotate. In a distribution type fuel injection pump that controls fuel injection timing by changing the relative position between the rotor and the fuel injection pump, there is provided a reference position sensor that detects an engine rotation reference position from the rotation of the rotor; An injection start sensor for detecting the start of injection is provided, and the advance angle of the injection timing with respect to the engine reference position is detected based on the phase difference between the output of the reference position sensor and the output of the injection start sensor, thereby achieving the above object. It is something.

[Effect of invention]

As described above, the present invention provides a distribution type fuel injection pump, in particular, a reference position sensor that detects an engine rotation reference position from the rotation of the rotor;
An injection start sensor is provided on the roller ring and detects the start of fuel injection from rotation of the rotor. That is, both the reference position sensor and the injection start sensor are signals detected as the rotor rotates, for example, signals detected by signal generating units provided on the outer periphery of the rotor in accordance with the number of cylinders. Output. In this way, both the reference position sensor and the injection start sensor detect the signal generating part on the outer periphery of the rotor. is not attached, but is attached to the roller ring as described above. In the distribution type fuel injection pump to which the present invention is applied, the relative position between the roller ring (cam member) and the roller is changed by rotating the roller ring within the pump housing using, for example, a timer piston or the like. and controls the fuel injection timing. Therefore, since the injection start sensor is attached to this roller ring as described above, the phase difference between the output of the reference position sensor and the output of the injection start sensor is accurately determined by the difference between the roller ring and the roller. It can be detected according to changes in relative position. Naturally, compared to the method of detecting the stroke position of a conventional stroke type timer, the stroke position can be detected much more accurately using a simple detector. By controlling the fuel pumping period according to the output of the output sensor of the injection start sensor, it becomes possible to accurately control the fuel injection amount. In addition, if the fuel injection timing is controlled by the advance angle of the injection timing with respect to the engine reference position, which is determined based on the phase difference between the output of the reference position sensor and the output of the injection start sensor, accurate fuel injection timing can be determined. Control becomes possible. Note that the present invention does not limit the signal generating section provided on the outer periphery of the rotor; for example, the signal generating section may be detected by a reference position sensor or by an injection start sensor. By standardizing the parts, parts costs can be reduced. Further, whether or not they are shared, it is possible to obtain the effect that the phase difference between the output of the reference position sensor and the output of the injection start sensor can be accurately detected.

【Example】

Embodiments of the present invention will be described in detail below with reference to the drawings. As shown in FIG. 3, this embodiment has a drive shaft 12, a plunger 14, a roller ring 16, a roller 18, a cam plate 20, a pump housing 22, a timer piston 24, a slide pin 26, and a feed pump similar to the conventional example. 30, compression spring 3
2. In a solenoid valve spill type distributed fuel injection pump having a delivery valve 40, a solenoid 42, etc., there are teeth for rotation detection on the outer periphery disposed on the drive shaft 12 and for generating a signal corresponding to the number of cylinders. The rotation of the engine is detected from the approach of the rotor 60 provided with a notch, and the teeth are arranged near the outer circumference of the rotor of the pump housing 22, and the reference position of the engine rotation is detected from the approach of the notch. For example, a rotation and reference position sensor 62 for detecting the top dead center, and an injection start sensor 64 disposed near the outer circumference of the rotor of the roller ring 16 for detecting the start of injection from the approach of the notch. The engine rotation is detected based on the output of the rotation and reference position sensor 62, and the advance angle of the injection timing with respect to the engine reference position is detected based on the phase difference between the output of the rotation and reference position sensor 62 and the output of the injection start sensor 64. is detected, and furthermore, the injection end timing by the solenoid 42 is controlled based on the output of the injection start sensor 64. The rotation and reference position sensor 62 and the injection start sensor 64 include a permanent magnet 62A for forming a magnetic circuit with the outer circumference of the rotor 60, and the rotor 60, as shown in FIGS. 4 and 5, for example. Magnetoresistive element 62B for detecting changes in magnetic flux caused by the approach of teeth or notches formed on the outer periphery of the magnetoresistive element 62B.
and a permanent magnet 62C for applying a predetermined bias to the magnetoresistive element 62B. The action will be explained below. When the drive shaft 12 rotates as the engine rotates, the rotor 60 rotates. Therefore, the rotation and reference position sensor 62 and the injection start sensor 64
detects the approach of the teeth formed on the outer periphery of the rotor 60 and their notches, and generates an output signal. The output generated from the rotation and reference position sensor 62 varies depending on the engine rotation and reference position, for example, top dead center, and the signal output from the injection start sensor 64 changes depending on the engine rotation and reference position, for example, top dead center. The rotation angle changes in response to the start of fuel injection. Therefore, as shown in Figure 6,
After the top dead center is detected by the output of the rotation and reference position sensor 62, the injection start sensor 64
By detecting the phase difference until the start of injection is detected by the output of , it is possible to determine the advance angle of the injection timing with respect to the engine reference position (top dead center). Further, after a predetermined time T has elapsed since the output of the injection start sensor 64 is generated, the solenoid 42
By activating this, fuel injection is terminated, thereby making it possible to accurately control the fuel injection amount Q. In this embodiment, teeth for detecting the engine rotation are provided on the outer periphery of the rotor 60, and the signal generating portion corresponding to the number of cylinders is the notch, so that the detection of the engine rotation and the reference position can be performed using a single sensor. 6
2, and the configuration is simple. In addition,
The configuration of the reference position sensor is not limited to this, and may be separate from the rotation sensor, for example, the pump drive shaft 12.
It is also possible to configure the reference position to be detected from the rotational displacement of the pump pulley for driving the pump pulley. Further, in this embodiment, the present invention is applied to a solenoid valve spill type distribution type fuel injection pump, and the rotation and reference position sensor 62 and the injection start sensor 6
The configuration is particularly simple because the engine rotation and the advance angle of the injection timing are not only detected in accordance with the output of the solenoid 42, but also the timing at which the solenoid 42 is actuated is controlled. It should be noted that the scope of application of the present invention is not limited to this, and it is obvious that it can be similarly applied to other types of fuel injection pumps other than the electromagnetic valve spill type. In the above embodiment, the signal generating section is a notch in a tooth formed on the outer periphery of the rotor, and both the rotation and reference position sensor 62 and the injection start sensor 64 utilize changes in magnetic resistance to detect the tooth or notch. However, the shape of the signal generating section formed on the outer periphery of the rotor, the specific configuration of the reference position sensor, and the injection start sensor are not limited to this.

[Effect of the idea]

As explained above, according to the present invention, it is possible to omit a stroke type timer position sensor having a complicated configuration, and the advance angle of the injection timing can be detected easily and accurately. Moreover, it has excellent effects such as lower production costs and improved reliability.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the configuration of a conventional electromagnetic valve spill type distribution fuel injection pump, FIG. 2 is a cross-sectional view taken along the - line in FIG. 1, and FIG. 3 is an injection pump according to the present invention. FIG. 4 is a sectional view showing the configuration of a solenoid valve spill type distribution fuel injection pump in which an embodiment of the timing detection device is arranged, and FIG. 4 shows the arrangement of the rotation and reference position sensor or the injection start sensor in the embodiment. FIG. 5 is a front view showing the state, FIG. 5 is a side view, and FIG. 6 is a diagram showing examples of signal waveforms at various parts of the embodiment. 10... Distribution fuel injection pump, 12... Drive shaft, 14... Plunger, 16... Roller ring, 18... Roller, 20... Cam plate, 2
2... Pump housing, 24... Timer piston, 26... Slide pin, 60... Rotor, 6
2... Rotation and reference position sensor, 64... Injection start sensor.

Claims (1)

[Claims for Utility Model Registration] A rotor and a cam member that rotate in synchronization with the rotation of a drive shaft, a rotatable roller ring that rotatably supports a roller that rolls on the surface of the cam member,
and a fuel pumping plunger that pumps fuel to the engine by reciprocating motion, and the cam member and the roller obtain the reciprocating motion of the fuel pumping plunger from the rotational motion of the drive shaft, and the cam is rotated by rotating the roller ring. A distribution type fuel injection pump that controls fuel injection timing by changing the relative position between a member and a roller, comprising: a reference position sensor that detects an engine rotation reference position from the rotation of the rotor; An injection start sensor is provided to detect the start of fuel injection from the rotation of the rotor, and the advance angle of the injection timing with respect to the engine reference position is detected based on the phase difference between the reference position sensor output and the injection start sensor output. An injection timing detection device for a distribution type fuel injection pump, characterized by: