JPS6380067A - Injection timing detecting device and fuel injection control device for fuel injection pump - Google Patents

Abstract

PURPOSE:To carry out fuel injection timing control and fuel injection amount control with a high degree of accuracy, by providing a pressure detector for detecting the load of a spring urging a plunger in a fuel injection pump and a computing means for calculating the pressurization initiating timing of the plunger. CONSTITUTION:A pressure detector 32 is provided in a seat section 31 for a spring 7 urging a plunger 5in a fuel injection pump 1 in order to detect the load of the spring 7. A rotating angle detector 36 delivers a signal indicating the rotating angle of a rotor 35. An electronic control device 50 calculates the pressurization initiating timing of the plunger 5 in accordance with the phase angle of a load signal from the detector 32. Thus, since that fuel injection timing may be directly detected with a high degree of accuracy by use of a simple structure, thereby it is possible to easily realize fuel injection timing control and fuel injection amount control.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fuel injection pump that controls combustion in a diesel engine, and more particularly to a device that detects fuel injection timing and controls the injection timing and injection amount.

"Prior Art" In a distribution type fuel injection pump, injection timing is generally controlled by a hydraulic timer mechanism. In recent years, feedback control is often used because more precise control is required. Conventionally, means for detecting injection timing include detecting the position of a timer piston of a hydraulic timer mechanism using a position sensor such as a differential transformer (Japanese Patent Publication No. 60-53777);
One that detects the lift of the injection nozzle of each cylinder, or one that directly detects the start of combustion in each cylinder using an optical sensor (
Special Publication No. 60-55695) is known.

The method that detects the position of the timer piston has the problem of a complicated mounting structure for the position sensor, and a lack of accuracy because the injection timing is detected indirectly from the amount of operation of the timer mechanism. . In addition, the method that detects by lift of the injection nozzle or optical sensor is superior in that it directly detects the injection timing, but it has a cost problem, and especially the former cannot detect the nozzle part where the usage environment is harsh. Therefore, there was a problem that reliability could be lacking.

Furthermore, in an electromagnetic spill type fuel injection pump that controls the injection amount by causing high-pressure fuel pressurized by a plunger to overflow through an electromagnetic valve, it is important to detect the injection start timing. The injection amount is determined by the lift amount of one lange after the fuel is pressurized and starts injection until it is overflowed by the solenoid valve, and the pressurization start timing changes depending on the operation amount (advance amount) of the hydraulic timer mechanism. Because it does. Conventionally, as a means to eliminate the influence of the timer advance amount, a sensor such as an electromagnetic pickup is mounted on a roller ring that is rotationally driven by the timer piston and whose rotational position changes according to the timer advance amount. A device is known that detects a relative rotation angle by detecting a protrusion of a rotor attached to a rotating shaft (Japanese Patent Application Laid-open No. 47252/1982).

In this device, the roller ring inevitably vibrates due to the reaction force of the pressurized drive of the plunger, so the sensor is required to have strong vibration resistance.Furthermore, since the roller ring is not fixed, it causes errors in rotation angle detection. The problem was that it was easy.

[Problems to be Solved by the Invention] The present invention has been made to solve the above problems, and provides an injection timing detection device for a fuel injection pump that can easily and accurately detect the injection timing. It is an object of the present invention to provide a fuel injection control device that controls fuel injection timing and fuel injection amount using the injection timing detection means.

"Means for Solving the Problems" The present invention, as shown in FIG. This is an attempt to directly detect the injection timing.

In a first invention, a rotor is fixed to a rotating shaft of a fuel injection pump and has a protrusion on its outer periphery for giving angle information, and a protrusion of the rotor is fixed to a fixed part such as a housing of the fuel injection pump. a rotation angle detector that detects the passage of the fuel injection pump and outputs a rotation angle signal; and a pressure sensor that is provided on the seat of a spring that biases the plunger of the fuel injection pump and that detects the load of the spring and outputs a load signal. It is characterized by comprising a detector, a phase angle detecting means for detecting a phase angle of the load signal with respect to the rotation angle signal, and an arithmetic means for calculating a pressurization start timing of the plunger based on the phase angle. An injection timing detection device for a fuel injection pump is provided.

The second invention controls the fuel injection timing, and in addition to the phase angle detection means, an electromagnetic adjustment valve that can adjust the pressure in the high pressure chamber of the fuel injection pump and adjust the position of the timer piston. , electrical 9161 means for controlling the electromagnetic adjustment valve to correct an error between the phase angle detected by the phase angle detection means and the target phase angle calculated from the target injection timing; A fuel injection control device is provided.

The third invention controls the fuel injection amount, and includes, in addition to the phase angle detection means, an electromagnetic spill valve that opens at a desired timing to cause high-pressure fuel to overflow and control the fuel injection amount. , a spill timing in which the basic overflow angle calculated from the engine operating condition is corrected based on the phase angle detected by the phase angle detection means, and the electromagnetic spill valve is opened at the corrected overflow angle. A fuel injection control device is provided, comprising: a control means.

``Operation'' In the device configured in this way, the rotation angle detector is fixed to a fixed part such as the housing of the fuel injection pump, so it can accurately measure the rotation angle of the rotation shaft without being affected by vibrations, etc. can be detected. Since the pressure detector detects the load of the spring that biases the plunger, the load signal becomes a signal that indicates a change directly corresponding to the amount of push of the plunger, and the pressure driving force of the plunger also indicates the fuel injection. Changes in the timing at which the plunger is pushed are detected by detecting changes in the phase angle of the load signal, which is a stable signal that is not affected by changes in quantity, and changes periodically with the rotation of the 0-rotation shaft, relative to the rotation angle signal. This makes it possible to directly detect changes in fuel injection timing using a hydraulic timer mechanism or the like.

Further, in the second invention, since the oil pressure of the timer piston high pressure chamber is adjusted so that the phase angle of the load signal with respect to the rotation angle signal becomes a value corresponding to the target injection timing,
Highly accurate injection timing control becomes possible.

In the third invention, since the overflow timing at which the electromagnetic spill valve is opened and the high-pressure fuel overflows is corrected based on the phase angle of the surface load signal with respect to the rotation angle signal, the hydraulic timer a structure or the like is used. 1 It is possible to compensate for changes in the timing of the start of the lange lift and overflow at the time when the correct amount of lift is achieved, making it possible to control the injection amount with high precision based on the rotation angle signal detected at a fixed position. Become.

"Embodiments" Examples of the present invention will be specifically described with reference to the drawings.

FIG. 1 is a sectional view showing a fuel injection pump to which the present invention is applied, and FIG. 2 is a sectional view taken along the line ■--■ in FIG.

The fuel injection pump 1 is of an electromagnetic spill type based on a known Bosch type distribution fuel injection pump. A rotary shaft 2, which is driven to rotate at 1/2 the speed of the engine crankshaft in synchronization with the engine crankshaft, rotates a vane type feed pump 3, and also rotates a plunger 5 via a coupling 4.
and rotates the face cam 6. The coupling 4 restrains the plunger 5 in the rotational direction and integrally drives the plunger 5, but allows it to freely reciprocate in the axial direction. The plunger 5 and the face cam 6 are integrally provided.

The face cam 6 has four cam ridges corresponding to the number of cylinders of the engine, and is pressed against a cam roller 8 by a spring 7. The sliding contact between the cam roller 8 and the two-ace cam 6 causes the plunger 5 to reciprocate while rotating.

The cam roller 8 is held by a roller ring 9. This roller ring 9 is provided so as to be rotatable within an angular range of several tens of degrees, and its rotational position is controlled by a timer piston 10 via a pin 11. The sliding timing between the cam roller 8 and the face cam 6 is shifted depending on the rotational position of the roller ring 9, and the phase angle of the reciprocating motion of the plunger 5 with respect to the rotational angular position of the rotating shaft 2 changes. These roller ring 9, timer piston 10, etc. form a hydraulic timer i which controls the fuel injection timing.

The position of the timer piston 10 is determined by the differential pressure between the high pressure chamber 12 and the low pressure chamber 13 and the load of the timer spring 14.

The high-pressure chamber 12 communicates with the high-pressure side of the vane-type feed pump 3, that is, the fuel chamber 15, via a throttle (not shown), and the low-pressure chamber 13 communicates with the low-pressure side of the vane-type feed pump 3. The high pressure chamber 12 and the low pressure chamber 13 are controlled by an electromagnetic regulating valve 16.
The pressure in the high pressure chamber 12 is adjusted by the opening degree of the electromagnetic adjustment valve 16, and the position of the timer piston 10 is adjusted.

The plunger 5 has a head 21 fixed to the housing 17.
The head 21 and the end face of the plunger 5 form a pump chamber 22. Fuel sucked from the fuel chamber 15 through a suction hole (not shown) is pressurized by the plunger 5. The high-pressure fuel pressurized within the pump chamber 22 is sent to the discharge valve 24 for each cylinder via the distribution boat 23 selected by the rotational position of the plunger 5, and is then sent under pressure to the injection nozzle of each cylinder of the engine body. and is injected.

Further, the pump chamber 22 communicates with an electromagnetic spill valve 26 via a communication passage 25. The electromagnetic spill valve 26 opens and closes the communication passage 25 and the overflow passage 27 communicating with the fuel chamber, and is a valve that is closed when energized. Therefore, during the compression stroke of the plunger 5, the electromagnetic spill valve 26
When power is cut off, the high-pressure fuel is released into the fuel chamber 15 via the communication passage 25 and the overflow passage 27, and is no longer forced to be fed to the discharge valve 24, so that fuel injection is stopped. Solenoid spill valve 2
The fuel injection amount in each cylinder is controlled by controlling the timing of cutting off the energization to cylinder 6.

An annular pressure detector 32 is provided on the seat portion 31 of the spring 7 that urges the plunger 5 and the face cam 6 in the axial direction. The pressure detector 32 consists of a piezoelectric element,
The load on the spring 7 is detected and an analog voltage signal is output.

In order to detect the rotational position of the rotating shaft 2, a rotor 35 having a protrusion on its outer periphery is fixed to the rotating shaft 2, and the housing 1
A rotation angle detector 36 is fixed to 7. As shown in FIG. 2, the rotor 35 is provided with protrusions 37 at equal intervals on its outer periphery like the teeth of a gear, and has missing portions 38 in which one protrusion is missing at four locations. The missing portion 38 provides information on the reference angular position, and is located 2 before the top dead center (TDC) of each cylinder.
The zero rotation angle detector 36, which is set at a position near 0 degrees, is a detector consisting of an electromagnetic pickup, and detects the passage of the protrusion 37 following the missing portion 38, and determines the rotational position of the rotating shaft 2, that is, the rotation of the crankshaft. Detect angular position.

Electronic control bag W (ECU) with microcomputer
50 receives signals from an accelerator position sensor 51, a water temperature sensor 52, an intake air temperature sensor 53, etc. that provide engine operating state signals. The electronic control device 50 controls the opening degree of the electromagnetic adjustment valve 16 and the opening/closing timing of the electromagnetic spill valve 26 based on these operating state signals, the rotation angle signal from the rotation angle detector 36, and the spring load signal from the pressure detector 32. Control.

The fuel injection timing control means will be explained based on the above mechanical configuration.

The opening degree of the electromagnetic regulating valve 16 that determines the position of the timer piston 10 is controlled by the opening/closing time ratio (duty ratio) of the electromagnetic regulating valve 16. When the duty ratio is small and the solenoid regulating valve 16 is almost open, the timer piston 10 moves fully toward the high pressure chamber 12, as shown in FIG. 3(b).
Since the roller ring 9 moves in the rotational direction of the rotating shaft 2, the timing at which the cam crest of the face cam 6 rides on the cam roller 8 is delayed, and fuel is injected at the most retarded angle.

This corresponds to times such as idling. When the duty ratio increases and the time during which the electromagnetic regulating valve 16 is closed increases,
As shown in FIG. 3(,), the timer piston 10 moves toward the low pressure chamber 13, and fuel is injected at a faster advance.

FIG. 4 is a waveform diagram showing a rotation angle signal and a load signal.

The rotation angle signal after shaping shows a waveform corresponding to the protrusion 37 of the rotor 35, and the signal missing time 61 corresponding to the missing portion 38 is
The pulse signal that appears for the first time after the missing period 61 is a reference pulse 62, which is a pulse signal that is continuously generated at every predetermined rotation angle. The reference angular position 63 is set as the reference angular position 63. As mentioned previously, the reference angular position 63 is set at a crank angle position around 20 degrees before the top dead center of each cylinder.

The load signal from the pressure detector 32 is transmitted to the face cams 6 and 1.
The voltage waveform corresponds to the lift amount of the langeer 5. Fourth
The waveform 65 shown by a solid line in the figure shows the load signal at the most retarded position when the timer piston 10 has moved fully toward the high pressure chamber 12 side, and the waveform 66 shown by a broken line shows the load signal at the position where the timer piston 10 is advanced. Show signal.

In any case, the waveforms 65 and 66 of the load signal are not affected by changes in the driving force that pressurizes the plunger 5 or changes in the fuel injection amount, and show stable waveforms that directly correspond to the lift amount of the plunger 5. .

The phase angle of the load signal with respect to the rotation angle signal is at the reference angle position 6.
From point 3 onwards, the load signal 65 given as an analog voltage
．． 66 is detected as the rotation angle up to the point when it crosses a predetermined comparison voltage 67. The rotation angle is determined by counting the number of pulse signals of rotation angle signals generated after the reference pulse 62, and calculating the interpolation between the pulse signals by converting the engine rotation speed into time.

Then, the phase angle α1 of the load signal 65 at the most retarded time when the timer piston 10 has moved fully toward the high pressure chamber 12 is determined in advance, and the phase angle α1 of the load signal 66 at the most advanced time, which is during normal operation, is determined in advance. α2 is detected, and the advance angle amount β during driving can be calculated from the difference (α1-α2). The calculated advance angle amount β is used as feedback 1 to adjust the opening degree of the electromagnetic adjustment valve 16 and control the fuel injection timing.

FIG. 5 is a flowchart showing actual processing by the microcomputer within the electronic control unit 50.

When the fuel injection timing control process 100 is started, first,
In step 101, engine operating state signals are read, that is, the accelerator position sensor 51 and the water temperature sensor 5.
2. Signals from the intake air temperature sensor 53, etc. are simulated and read by the A/D7R. Further, the engine rotation speed is calculated from the period of the rotation angle signal. In step 102, the phase angle α of the load signal 65 in the idle state at the most retarded angle is detected. That is, it is determined whether the engine is in an idling state based on the signal from the accelerator position sensor 51 and the rotational speed of the engine.
The 0 phase angle α, at which the time point when the phase angle 7 is crossed is detected and the phase angle α, is calculated, is stored in a predetermined memory. Step 103
Then, the basic injection timing obtained by searching and interpolating the two-dimensional mag of engine speed and accelerator opening is corrected by intake air temperature, etc., and the target advance angle β indicating the target injection timing is calculated.
Calculate T. This target advance angle amount βT is calculated as the advance angle amount from the i-angle position determined from the mechanical structure of the hydraulic timer mechanism.

In step 104, the current load signal 66 is set to the comparison voltage 6
7 is detected, and the reference position 63 is detected to determine which phase difference α
2 is calculated. In step 105, the current advance angle amount β
is calculated as β=α2−α1. The value of the advance angle β is a value representing the actual advance angle amount of the injection timing which is not influenced by the value of the comparison voltage 67. In step 106, the error ε (ε=βT
−β) is calculated. Then, in step 107, it is determined whether the error ε is positive or negative. If the error ε>0, the advance angle amount is insufficient, so the process proceeds to step 110, the duty ratio of the electromagnetic regulating valve 16 is increased, the closing time is increased, and the timer piston 10 is moved to the advance angle side. If the error margin is 0, the process proceeds to step 108, where the duty ratio is reduced, the closing time of the solenoid valve 16 is reduced, and the timer piston 10 is moved to the retard side. If the error ε=0, the process proceeds to step 109 and the current duty ratio is maintained. Thereafter, steps 101 to 1 are performed at appropriate intervals.
Repeat step 10.

As described above, the fuel injection timing can be controlled with high precision by using the load signal of the spring 7 that biases the plunger 5 as a feedback signal.

Next, the means for controlling the fuel injection amount will be explained.

The fuel injection amount is controlled by the timing at which the electromagnetic spill valve 26 is de-energized.

FIG. 6 is a waveform diagram showing the energization signal etc. of the electromagnetic spill valve 26.

The waveforms of the rotation angle signal and the load signal are the same as those already explained in FIG. It is assumed to be T163. The load signal waveform 65 at the most retarded time of the timer piston 10 is shown by a solid line, and the load signal waveform 66 at the most advanced time is shown by a broken line.Similarly, the solid line waveform 67 shows the lift amount characteristics of the plunger 5. The broken line waveform 68 indicates the time when the angle is retarded, and the broken line waveform 68 indicates the time when the angle is advanced.

Here, the phase angle of the load signal is detected as the rotation angle from the reference angular position 63 at the time when the load signal corresponding to the top dead center of the plunger 5 shows a peak voltage.

The phase angle α of the load signal 65 at the most retarded time when the timer piston 10 has moved fully toward the high pressure chamber 12. is determined by the mechanical structure of the timer mechanism and given as a set value. Then, the phase angle α of the load signal 66 during operation is detected, and the i&
Phase angle α during retardation. Based on which phase difference Δα, the opening timing of the electromagnetic spill valve 26 is corrected and the fuel injection amount q is controlled.

FIG. 7 is a flowchart showing actual processing within the electronic control unit 50.

When the fuel injection amount control process 200 is started, in step 201, operating state signals are read from each sensor 51, 52, 53, etc. Next, in step 202, the engine state signal and rotation angle signal are read. The optimum injection amount q is calculated from the engine rotation speed calculated from the cycle. In step 203, the basic spill angle (basic overflow angle) corresponding to the above injection amount q is θ. is calculated. Basic spill angle θ. is the reference angular position 63, which is the overflow timing to achieve the above injection amount q when the timer piston 10 is at the most retarded position.
It is expressed as a rotation angle from .

In step 204, the phase angle α of the load signal 66 detected and stored during the previous lift of the plunger 5 is read out. In step 205, the phase angle α at the most retarded angle given as the pre-caulking setting value is detected. The phase difference Δα from the phase angle α is Δα=α. −α is calculated as 0. Then, in step 206, the command spill angle θ is calculated.
The command spill angle θ is the basic spill angle θ. is corrected by the phase difference Δα, and θ=θ. −Δα.

In step 207, the time required to reach the command spill angle θ is calculated, and the calculated time is set in a predetermined output register. After this concentration and a set time have elapsed, the energization to the electromagnetic spill valve 26 is cut off, and the high-pressure fuel overflows at the commanded spill angle θ.

As described above, by detecting the phase angle of the load signal of the spring 7 that biases the plunger 5, the fuel injection amount is increased based on the rotation angle signal from the rotation angle sensor 36 fixed to the housing 17. Can be controlled with precision.

In addition, in the above embodiment, in order to obtain the phase angle of the load signal,
It is determined by the rotation angle at the point when the load signal crosses an appropriate comparison voltage (Figure 4), or by the rotation angle at the peak voltage of the load signal (Figure 6), but either of these methods may be used. Alternatively, the rotation angle at the time corresponding to the beginning of the lift of the plunger 5 may be determined.

"Effects of the Invention" As described above, the present invention has the above configuration, detects the load of the spring that biases the plunger, and detects the operation timing of the plunger based on the phase angle of the load signal. This has the excellent effect that the fuel injection timing can be directly and accurately detected with a simple structure, and that highly accurate fuel injection timing control and fuel injection amount control can be easily performed.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a sectional view showing the overall structure, FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1, and FIG. 3 is a sectional view explaining the operation of the timer mechanism. Fig. 4 is a waveform diagram explaining the operation of fuel injection timing control, Fig. 5 is a flowchart showing its actual processing, Fig. 6 is a waveform diagram explaining the operation of fuel injection amount control, and Fig. 7 is its actual process. 3 is a flowchart showing the processing of FIG. 111. Fuel injection pump, 2111 rotating shaft, 59.
. Plunger, 611. Face cam, 711. Spring, 905. roller ring, 10. ,, timer piston, 16. ,, Solenoid regulating valve, 17. ,
, housing, 26 ,, electromagnetic spill valve, 31
,,, seat part of the spring, 32. ,,Pressure detector, 35, ,Rotor, 36, ,Rotation angle detector,
37°0. Protrusion, 50, . 44 children production device. Figure 2 Figure 4 (a) 3 houses (b) Figure 5 Figure 6

Claims (1)

[Scope of Claims] 1. A rotor that is fixed to a rotating shaft of a fuel injection pump and has a protrusion on its outer periphery for providing angular information, and a rotor that is fixed to a fixed part such as a housing of the fuel injection pump and that a rotation angle detector that detects the passage of a protrusion and outputs a rotation angle signal; and a rotation angle detector that is provided on the seat of a spring that biases the plunger of the fuel injection pump, and that detects the load of the spring and outputs a load signal. A pressure detector; a phase angle detecting means for detecting a phase angle of the load signal with respect to the rotation angle signal; and an arithmetic means for calculating a pressurization start timing of the plunger based on the phase angle. An injection timing detection device for a fuel injection pump. 2. An electromagnetic adjustment valve capable of adjusting the pressure in the high pressure chamber of the timer piston of the fuel injection pump and the position of the timer piston, and a protrusion fixed to the rotating shaft of the fuel injection pump and provided on the outer periphery for providing angle information. a rotor fixed to a fixed part such as a housing of the fuel injection pump, a rotation angle detector that detects passage of a protrusion of the rotor and outputs a rotation angle signal, and a spring that biases a plunger of the fuel injection pump. a pressure detector which is provided on the seat portion of the spring and which detects the load of the spring and outputs a load signal; a phase angle detection means which detects a phase angle of the load signal with respect to the rotation angle signal; and the phase angle detection means. and an electric control means for controlling the electromagnetic regulating valve so as to correct the error in accordance with the error between the phase angle detected by the target phase angle and the target phase angle calculated from the target injection timing. Fuel injection control device. 3. An electromagnetic spill valve that opens at a desired timing to cause high-pressure fuel to overflow and control the fuel injection amount, and a protrusion that is fixed to the rotating shaft of the fuel injection pump and provided on the outer periphery to provide angle information. a rotor fixed to a fixed part such as a housing of the fuel injection pump; a rotation angle detector that detects passage of a protrusion of the rotor and outputs a rotation angle signal; and energizes a plunger of the fuel injection pump. a pressure detector provided on the seat portion of the spring to detect the load of the spring and output a load signal; a phase angle detection means to detect the phase angle of the load signal with respect to the rotation angle signal; and an operating state of the engine. Spill timing control means for correcting the basic overflow angle calculated from the above based on the phase angle detected by the phase angle detection means, and opening the electromagnetic spill valve at the corrected overflow angle. A fuel injection control device characterized by: