JPS61135980A - Valve opening pressure detecting device and valve opening pressure control device for fuel injection valve - Google Patents

Abstract

PURPOSE:To permit to detect a valve opening pressure without providing the fuel injection valve itself with any sensor and control the valve opening pressure correctly for a long period of time by a method wherein the actual valve opening pressure of the fuel injection valve is operated in accordance with the revolving nubmer of an engine, fuel injection amount and fuel injection pressure. CONSTITUTION:The system is equipped with a revolution sensor 23, detecting the revolving number N of the engine, a pressure sensor 24, detecting the fuel injection pressure P of the fuel injection pump, and an injection amount detecting means 200, detecting the fuel injection amount Q of the fuel injection pump. The time T of output, higher than the predetermined thereshold level of the pressure sensor 24, is operated by a time operating means 600 and the actual valve opening pressure P0 of the fuel injection valve is operated in an actual valve opening pressure detecting means 700 from the output time T and said respective data N, Q. An objective valve opening pressure SOLL is operated by an operating means 300 from the revolving number N of the engine and is compared with the actual valve opening pressure P0 in a compar ison means 400. A valve opening pressure regulating means 100 is controlled in accor dance with the result of the comparison through a controlling means 500.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides a detection device for detecting the valve opening pressure of a fuel injection valve;
The present invention relates to a control device that controls valve opening pressure using this detection device, and is used in a fuel injection device for an internal combustion engine.

(Prior Art) In this type of fuel injection device, the valve opening pressure of the fuel injection valve is controlled according to the operating state of the internal combustion engine, and for example, when the rotation speed of the internal combustion engine is low, the valve opening pressure is set low. , it has been well known that if the noise level is high, it can be set high to reduce noise and exhaust gas. In order to accurately control this valve opening pressure, it is necessary to detect the actual valve opening pressure of the fuel injection valve and feed it back to the control circuit. 102526
This method is publicly known from Japanese Patent No. 10257 and No. 10257. Both detect the operating state of the internal combustion engine, calculate the target valve opening pressure based on this detected value, detect the actual valve opening pressure of the fuel injection valve, and correct the target value using this valve opening pressure. However, the valve opening pressure is adjusted so as to reach this corrected target value. Therefore, as a means of detecting the actual valve opening pressure, the former method detects when the fuel injection valve opens with a lift sensor installed in the injection valve, and also detects the internal pressure of the injection pipe with a pressure sensor. However, a method is adopted in which the pressure detected by the pressure sensor when the fuel injection valve is opened by the lift sensor is used as the valve opening pressure, and the latter detects the setting force of the spring that adjusts the valve opening pressure of the fuel injection valve. A setting force sensor is provided, and the output of this setting force sensor is detected as the valve opening pressure.

(Problem to be Solved by the Invention) However, since both have a configuration in which a lift sensor or a set force sensor is provided directly to the fuel injection valve installed in the internal combustion engine, these sensors are subject to heat and vibration from the internal combustion engine. , the environment is such that it is difficult to maintain the durability and reliability of the sensor. Therefore, in the past, there was a problem that an error occurred in the valve opening pressure signal that was to be fed back to the control circuit, or the signal stopped being transmitted within a short period of time, making it impossible to accurately control the valve opening pressure. be.

Therefore, the present invention solves the conventional problems caused by providing a sensor in a fuel injection valve, improves the durability and reliability of a valve opening pressure detection device, and improves the durability and reliability of such a valve opening pressure detection device. An object of the present invention is to provide a valve-opening pressure control device having a valve-opening pressure control device, thereby making it possible to accurately control valve-opening pressure over a long period of time.

(Means for Solving the Problems) Therefore, the gist of the first invention of the present application is that, as shown in FIG. , a pressure sensor 24 that detects the fuel injection pressure P of the fuel injection pump driven by the internal combustion engine.
and a time calculation means 600 for calculating the output time T of the pressure sensor 24 equal to or higher than a predetermined threshold level;
The injection amount detection means 200 detects the fuel injection amount Q of the fuel injection pump, and the actual value of the fuel injection valve is determined based on the outputs of the injection amount detection means 200 and the rotation sensor 23, and the calculated value of the time calculation means 600. Valve opening pressure P. A valve opening pressure detecting device for a fuel injection device includes an actual opening valve pressure calculating means 700 for calculating the actual opening valve pressure.

Further, the gist of the second invention of the present application is that in addition to the valve opening pressure detection device, at least the rotation sensor 23
a target valve opening pressure calculation means 300 that calculates a target valve opening pressure 5OLL based on the output from the target valve opening pressure detection means 3;
a comparison means 400 for comparing the target value 5OLL of 00 with the detection value P0 of the valve opening pressure detection device 700; and a valve opening pressure for adjusting the valve opening pressure of the fuel injection valve according to the comparison result of the comparison means 400. The valve opening pressure control device for a fuel injection valve includes a control means 500 for controlling the output to the adjustment means 100.

(Function) Next, the principle of the present invention will be explained based on FIGS. 2 to 4. The injection pressure P of the fuel injected from the fuel injection pump
As shown in Fig. 2, even if the injection amount Q is constant,
Since this injection amount Q is a value integrated over time along the fuel injection characteristic line from the start of injection to the injection path, it fluctuates according to the fuel injection characteristic, and the fuel injection characteristic lines EI and E2 have a predetermined Schleph shift. Output time at hold level 5 or higher T +
.

If T2 corresponds and the output time T is measured, the injection i
The injection characteristics when 1Q is constant can be determined. This injection characteristic is determined by the rotational speed N of the internal combustion engine and the opening pressure P of the injection valve. As a result of experiments, it was found that the That is, as shown in FIGS. 3 and 4, when the valve opening pressure P0 is kept constant, the rate of increase in the injection amount Q increases as the rotation speed N increases with respect to the output time T.
Furthermore, when the rotation speed N is constant (for example, N2),
Valve opening pressure P for output time T. The rate of increase in the injection amount Q increases as the amount Q decreases. Therefore, the valve opening pressure P of the injection valve. is, when the rotational speed N and the injection amount Q are constant,
It changes according to the output time T, and when the rotation speed N and output time T are constant, it changes according to the injection amount Q, and the output time T
When injection iQ is constant, it is shown as a function of rotation speed N, output time T, and injection amount Q, so that it varies according to rotation speed N, so by inputting these signals, the valve opening pressure can be changed. P0 can be detected.

Therefore, in the present invention, the rotation speed N is determined by the rotation sensor 23, the output time T is determined by the pressure sensor 24 and the time calculation means 600, and the injection amount Q is determined by the injection amount detection means 200, and these input signals are obtained. The actual valve opening pressure P of the injection valve is calculated by the actual valve opening pressure calculating means 700 based on the actual valve opening pressure P of the injection valve. Let's calculate it. And this valve opening pressure P. and the target value 5OLL from the target valve opening pressure calculation means 300 are compared by the comparison means 400, and based on the comparison result of the comparison means 400, a control signal is obtained by the control means 500, and the valve opening pressure is adjusted according to this control signal. The adjustment amount of the means 100 is controlled, thereby achieving the above object.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 5, the fuel injection pump 1 is of a distribution type, for example, and a plunger 3 is connected via a cam plate 4 to a drive shaft 2 which rotates using an internal combustion engine (not shown) as a drive source. The fuel in the pump chamber 6 is discharged via the delivery valve 7. This discharged fuel is sent to the injection valve 9 via the injection pipe 8, and is injected from the injection valve 9 into the cylinder of the internal combustion engine. A control sleeve 10 is slidably fitted around the plunger 4, and the control sleeve 10 is moved by a governor actuator 11 to adjust the injection amount.

In the injection valve 9, a rod 12 connected to a needle valve in a nozzle body 11 is pressed by a spring 13, and the other end of the spring 13 is in contact with a piston 14. A pressure chamber 15 is formed in the upper part of this piston 14, and this pressure chamber 15 is connected to a hydraulic unit 16. This hydraulic unit 16 includes a hydraulic tank 17, a hydraulic pump 18 driven by the internal combustion engine, and this hydraulic pump 18.
A pressure regulating valve 19 adjusts the oil pressure from the hydraulic pump 18 to a predetermined value or less, and a solenoid valve 20 selects whether to send oil from the hydraulic pump 18 to the pressure chamber 15 or return oil in the pressure chamber 15 to the hydraulic tank 17. Be equipped. Therefore, when this solenoid valve 20 is set to the 1 position and oil is supplied to the pressure chamber 15, the pressure chamber 15
As the oil pressure increases and moves the piston 14 downward, the spring 13 is bent and its pressing force increases, increasing the opening pressure of the injection valve 9. On the other hand, when the solenoid valve 20 is set to the position ■ and the oil in the pressure chamber 15 is returned to the hydraulic tank 17, the valve opening pressure decreases, and when the solenoid valve 20 is set to the neutral position, the opening corresponding to the balanced position of the piston 14 occurs. The piston 14, the pressure chamber 15, and the hydraulic unit 16 constitute the valve opening pressure adjusting means 100 shown in FIG.

The control unit 21 receives a rotation speed signal corresponding to the rotation speed of the internal combustion engine from a rotation sensor 23, which is provided opposite to the sensing plate 22 fixed to the drive shaft 2 and is composed of an electromagnetic pickup or the like, and which is provided in the barrel 5. and a pressure signal corresponding to the injection pressure from a pressure sensor 24 made of a piezoelectric element or the like, and a pressure signal corresponding to the injection pressure from the governor actuator 1.
A position signal corresponding to the injection amount is input from a position sensor 25 provided in the control unit 21, and these input signals are subjected to operational amplification processing and outputted as a control signal to the solenoid valve 20. An example circuit is shown in FIG. In this embodiment, the position sensor 25 constitutes the injection amount detection means 200 shown in FIG. 1, but in addition to this embodiment, a position sensor may be provided directly on the control sleeve 10, Further, when a mechanical governor is used, the position of the control rack may be detected. Further, the pressure sensor 24 may be provided in the injection pipe 8.

In FIG. 6, the control unit 21 has a microcomputer 26.
6 is a central processing unit CPU, a read-only memory ROM,
This microcomputer 26 is a known device equipped with a random access memory RAM, a clock generator, an input/output control device I10, etc. The rotation signal from the rotation sensor 23 and the pressure signal from the pressure sensor 24 are sent to a waveform shaping circuit 27, respectively. .28, and the signals from the position sensor 24 are converted into digital signals and input via the A/D converter 29, respectively. Then, a control signal is calculated according to a program stored in the read-only memory ROM, amplified through a drive circuit 30, and outputted to the solenoid valve 20, and the content of the program is As shown in FIG.

In FIG. 7, the microcomputer starts executing processing from step 31 when the key switch is turned on and the power is turned on, performs initial settings in the next step 32, and proceeds to the next step 33. In step 33, signals from the rotation sensor, pressure sensor, and position sensor are input and temporarily stored in a predetermined area of the random access memory RAM.

In the next step 34, the read-only memory ROM
The rotation speed N-target valve opening pressure 5OLL characteristic stored in advance is read out to the central processing unit cPU, and the target valve opening pressure 5OLL is calculated by map calculation from this and the rotation speed information input in step 33. This step 34 constitutes the target valve opening pressure calculation means 300 shown in FIG.

Then, in the next step 35, the actual valve opening pressure P0 is calculated by means to be described later, and in the next step 36, the target valve opening pressure SOL L and the actual valve opening pressure P0 are compared, and both are compared. If they are not equal, a proportional control calculation is performed in step 37, and a control signal according to this proportionally calculated PID value is output to the solenoid valve in step 3, and SOLj
The processes of steps 35 to 38 are repeated until = P o, and in step 36 SOL L = P (
If it is determined to be l, the process proceeds to step 39, the solenoid valve is stopped, and the process returns to step 32. The above step 36 constitutes the comparison means 400 shown in FIG. 1, and steps 37 to 39 constitute the control means 500 shown in FIG.

In FIG. 8, the actual valve opening pressure P. In order to calculate, in step 351, the output S of the waveform shaping circuit 28 is
If S=1, the process of step 351 is repeated and the process waits. If S=1, the next step 352 and step 353 are performed.
At this point, the number C of reference clocks is counted until S-0 is reached (see FIG. 9).

In the next step 344, the output time T is obtained by multiplying the number C of reference clocks obtained in step 352 by the time A of the reference clocks. That is, an output time T corresponding to the time during which the injection pressure is equal to or higher than a predetermined threshold level is calculated, thereby forming the time calculation means 600 shown in FIG. 1.

In the next step 355, data C regarding the number of reference clocks is cleared, and in the next step 356, the number of revolutions N which is prestored in the read-only memory ROM is cleared.
The characteristics of = output time T - injection amount Q - valve opening pressure P0 are read out to the central processing unit CPU, and the actual opening is calculated from this, the rotation speed and injection amount information input in step 33, and the output time T obtained in step 354. The valve pressure P0 is determined by map calculation, and this step 346 constitutes the actual open valve pressure calculation means 700 shown in FIG.

In the above configuration, when the internal combustion engine is driven, the drive shaft 2 rotates, and the rotational force of the drive shaft 2 and the force in the reciprocating direction by the cam plate 4 are applied to the plunger 3 via the cam plate 4, causing the plunger 4 to rotate. and reciprocate. As a result, the amount and timing of the fuel in the pump 6 is adjusted, and the fuel is sent through the delivery valve 7, via the injection pipe 8 to the injection valve 9, and is injected from the nozzle body 11 into the cylinder of the internal combustion engine. The opening pressure of the injection valve 9 is adjusted according to the amount of deflection of the spring 13, and the amount of deflection is proportional to the oil pressure in the pressure chamber 15. controlled accordingly. In this control unit 21, as described above, the target valve opening pressure so
r, r- are calculated from the rotational speed N of the internal combustion engine, and the actual valve opening pressure P0 is calculated from the rotational speed N, injection 1ci, and output time T, and the target valve opening pressure 5OLL and the actual valve opening pressure are calculated. P. is compared and the control signal is corrected, making it possible to accurately control the valve opening pressure.

Note that in the above embodiment, only the rotation speed N was used as a parameter to calculate the target valve opening pressure, but it is also possible to add signals related to the operating state of the internal combustion engine such as the water temperature, fuel temperature, and load of the internal combustion engine. You can also do it.

(Effects of the Invention) As described above, according to the present invention, the actual valve opening pressure of the injection valve is calculated from the rotational speed of the internal combustion engine, the injection amount of the fuel injection pump, and the injection pressure injected from the fuel injection pump. As a result, the actual valve opening pressure can be detected without installing any kind of sensor on the injection valve itself.For this reason, the opening pressure of the injection valve can be simply controlled automatically using a feedback loop. In addition, the durability and reliability of the valve opening pressure detection device can be improved, so that the valve opening pressure can be accurately measured over a long period of time.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the valve opening pressure detection device and control device according to the present invention, Fig. 2 is a characteristic diagram showing the characteristics of output time T - injection pressure P, and Fig. 3 is a diagram showing the characteristics of output time T - injection amount. Q - Number of revolutions N
Figure 4 is a characteristic diagram showing the characteristics of output time T - injection amount Q.
- Valve opening pressure P. A characteristic diagram showing the characteristics, FIG. 5 is a schematic diagram showing an embodiment of the present invention, FIG. 6 is a block diagram of the control unit used in the above, and FIG. 7 is a control of the microcomputer used in the same control unit. FIG. 8 is a flowchart showing the main routine of the program, FIG. 8 is a flowchart of a routine for calculating the actual open valve pressure in the control program, and FIG. 9 is a timing chart for the control unit. ■...Fuel injection pump, 9...Injection valve, 23...
Rotation sensor, 24... Pressure sensor, 100... Valve opening pressure adjustment means, 200... Injection amount detection means, 300...
-Target valve opening pressure calculation means, 400...comparison means, 500
... Control means, 600... Time calculation means, 700.
・Actual opening valve pressure calculation means. ” V Ryota R mouth

Claims (2)

[Claims] 1. A rotation sensor that detects the rotation speed of an internal combustion engine, a pressure sensor that detects the fuel injection pressure of a fuel injection pump driven by the internal combustion engine, and a time calculation that calculates the output time of the pressure sensor above a predetermined threshold level. means, injection amount detection means for detecting the fuel injection amount of the fuel injection pump, and actual opening of the fuel injection valve based on the output of the injection amount detection means and the rotation sensor, and the calculated value of the time calculation means. 1. A valve opening pressure detection device for a fuel injection valve, comprising an actual opening valve pressure calculation means for calculating pressure. 2. A rotation sensor that detects the rotation speed of an internal combustion engine, a pressure sensor that detects the fuel injection pressure of a fuel injection pump driven by the internal combustion engine, and a time calculation that calculates the output time of the pressure sensor above a predetermined threshold level. means, an injection amount detection means for detecting the fuel injection amount of the fuel injection pump, and an actual opening of the fuel injection valve based on the output of the injection amount detection means and the rotary sensor, and the calculated value of the time calculation means. A valve opening pressure detection device for a fuel injection valve comprising an actual opening valve pressure calculation means for calculating a valve pressure, and a target valve opening pressure calculation means for calculating a target valve opening pressure based on at least an output from the rotation sensor. , a comparing means for comparing a target value of the target valve opening pressure detecting means and a detection value of the valve opening pressure detecting device, and an opening valve adjusting means for adjusting the valve opening pressure of the fuel injection valve according to the comparison result of the comparing means. A valve opening pressure control device for a fuel injection valve, comprising: control means for controlling output to the valve pressure adjustment means;