JPH0320761B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling a hydraulic actuator that controls the rotational phase angle, etc. of a fuel injection pump of an automobile.

If the response speed of a hydraulic actuator used in a digital control system with a feedback loop is slow, hunting may occur even with simple on/off control where the application time of the instruction signal is constant. Never. However, when increasing the response speed,
Hunting phenomenon is likely to occur.

This is almost always true in the control system.
This is because there are components of response delay and hysteresis. Furthermore, in digital control, in addition to the response delay and hysteresis mentioned above, the rise of the instruction signal sent to the hydraulic actuator, regardless of the magnitude of the control deviation value. , or the fact that the gain change at the end is forced to be abrupt makes hunting more likely to occur.

To solve these problems, conventionally, the signal to the hydraulic actuator is a periodic pulse signal that vibrates in both directions, and the duty ratio of the two directions is controlled, so that the average position of the hydraulic actuator is controlled vibrationally. However, the control is essentially similar to analog control, thereby preventing the hydraulic actuator from moving on and off excessively and causing hunting in its control. (pulse width modulation)
There are control methods such as

However, in these control methods based on duty ratio control, the solenoid valve used in the hydraulic actuator is constantly used in vibration mode, so the number of on/off times of the solenoid valve is equivalent to the number of vibrations.
Repeated turning off will degrade the durability of the solenoid valve, and it is not appropriate to employ such duty ratio control for controlling devices that require durability.

The purpose of the present invention is to solve the above problems.
An object of the present invention is to provide a method for controlling a hydraulic actuator that improves the responsiveness and control accuracy of a control system without impairing durability.

To explain the present invention based on an embodiment, FIG. 1 shows a hydraulic actuator control method according to an embodiment of the present invention used to operate an injection timing adjustment device 2 of a fuel injection pump 4 in a diesel engine 1. This figure shows a system diagram in the case where the hydraulic actuator referred to in the present invention is built into the injection timing adjustment device 2.

The gear 1c fitted on the crankshaft 1a of the diesel engine 1 and the gear 2c fitted on the input shaft 2a of the injection timing adjustment device 2 form a gear coupling, and the output shaft 2b of the injection timing adjustment device 2
drives the fuel injection pump 4, and the injection timing adjustment device 2 changes the rotational phase angle between the input shaft 2a and the output shaft 2b according to the operating state of the diesel engine 1. This is to appropriately set the injection timing in the fuel injection pump 4, and the injection timing adjustment device 2 uses a known one.

The hydraulic pump device 3 is driven via gears 2c and 3a, and the hydraulic pump device 3 is connected to a pipe 3b.
It serves as a constant oil pressure source for the solenoid valve 5F via the solenoid valve 5F.

A disc 1b for measuring rotational angle and rotation speed is fitted onto the crankshaft 1a, and a similar disc 4a is fitted onto the output shaft 2b, and the circumferences of each of the discs 1b and 4a are fitted. On the top, protrusions are arranged at equally divided positions in the circumferential direction, and the disc 1b
Electromagnetic pickups 5H and 5G for detecting the rotational position of the protrusion are fixedly installed at positions on the circumferences of the protrusions and 4a, respectively. Note that 5a and 5b are electric wires.

The electric wire 5c is an input interface 5 for inputting the displacement of the accelerator pedal that operates the diesel engine 1.
The electric wire 5d is for transmitting the water temperature in the water jacket of the diesel engine 1 to the input interface 5A, and the electric wire 5e is for transmitting the atmospheric temperature to the input interface 5A. , the electric wire 5v is for transmitting the temperature of the hydraulic oil in the hydraulic pump device 3 to the input interface 5A.

Input interface 5A, central processing circuit 5
B, memory 5E and output interface 5D
The electric wire 5k consists of one electric wire _5k0 in FIG. 3 and the other electric wire _5k2 not shown, and the output in the microcomputer 5 is electromagnetic via the electric wire 5m. It controls the valve 5F, and the solenoid valve 5
F is connected to the injection timing adjustment device 2 via the hydraulic pipe 5n.
It operates the hydraulic actuator inside.

As shown in FIG. 2, the input interface 5A is composed of a Schmitt circuit 5AB, an analog multiplexer 5AD and an A-D converter 5AE, and 5p, 5q, 5r, 5s and 5t are electric wires, respectively.

FIG. 3 shows one output interface 5D 1 in the circuit diagram of the output interface _{5D, and one electric wire 5k 1 ,} which is the output of the central processing circuit 5B, is connected to the resistor R ₁ . The electric wire 5u is connected to a constant voltage power supply, the electric wire 5m is connected to one solenoid 5F1 of the solenoid valve 5F in Fig. ₁ , D is a flywheel diode, and _R2 and _R3 are resistors. , TR ₁ and TR ₂
is a transistor.

The other output interface to which the other electric wire _5k2 is input is omitted because it is the same as in FIG. 3.

In the configurations shown in FIGS. 1, 2, and 3 above, to explain their functions, the diesel engine 1 is driven by the operation of an accelerator pedal (not shown), and the fuel injection pump 4 is driven by the crankshaft 1.
a, gears 1c and 2c, input shaft 2a, injection timing adjustment device 2 and output shaft 2b,
The injection timing adjustment device 2 is controlled by the rotation speed of the diesel engine 1, the displacement of the accelerator pedal, the water temperature of the water jacket (hereinafter simply referred to as water temperature), and the atmospheric condition. Hydraulic signal (control power) from 5n (multiple)
to operate the hydraulic actuator in the injection timing adjustment device 2 in one direction or the other,
As a result, the injection timing adjustment device 2 changes the relative rotational phase angle between the input shaft 2a (that is, also corresponds to the crankshaft 1a) and the output shaft 2b, and as a result, the injection timing of the fuel injection pump 4 is appropriately set. ing.

The injection timing is set by turning the solenoid valve 5F on or off to one side or the other according to the output instruction signal of the microcomputer 5, and the hydraulic signal from the solenoid valve 5F amplified by this operation indicates the injection timing. Although the adjustment device 2 is operated and set, the operation of the microcomputer 5 that controls the solenoid valve 5F will be explained below.

The temperature of the hydraulic oil in the hydraulic pump device 3, the displacement of the accelerator pedal, the water temperature, and the atmospheric temperature are detected in an analog manner by detectors (not shown), and as shown in FIG.
The respective detection values are alternately selected in the analog multiplexer 5AD by an occasional command signal from B via the electric wire 5r,
The alternately selected detection signals are converted from analog values to digital values in the A-D converter 5AE, and are respectively input to the central processing circuit 5B.

The respective rotation angles of the crankshaft 1a and the output shaft 2b are determined by the electromagnetic pickups 5H and 5.
G, and the respective detected signals are the signals 5as and 5bs shown in FIG.
The detection signal is input to the Schmitt circuit 5AB (FIG. 2).

Note that the horizontal axis in FIG. 6 indicates elapsed time.

Pulse signals sa and sb in FIG.
It shows the voltage change value that occurs when the voltage exceeds (passes).

Each of these pulse signals sa and sb is
In the Schmitt circuit 5AB (FIG. 2), the signals _pa1 and pb are converted into rectangular waveform pulse signals and input to the central processing circuit 5B.

As the rotational speed of the crankshaft 1a increases, the waveforms of the pulse signals sa and sb change as shown by sa', so the pulse signals _pa1 and pb whose waveforms are shaped with reference to the reference voltage level d are
pa changes as ₁ ′, but the pulse signals sa and sb
Since the positions of points a and b of zero voltage in are not affected by the rotational speed, the pulse signal pa ₁
and pb have their reference points at elapsed times corresponding to points a and b.

t ₁ and t ₂ each indicate the measurement time between the pulse signals pa ₁ and pb and the pulse signals pa ₁ and pa ₂ , respectively, and due to their properties, the input shaft 2a and the output shaft 2b The rotational phase angle pe between and the rotational speed n of the crankshaft 1a are as follows.

pe = (c ₁ × t ₁ ) / t ₂ ... (1) n = c ₂ / t ₂ ... (2) where c ₁ and c ₂ are constants determined by the number of protrusions on the discs 1b and 4a It is.

In the memory 5E in FIG. 1, various data necessary for calculation in the central processing circuit 5B are stored.

To explain an example of this stored data, for example, the fuel injection timing of the diesel engine 1 is determined by the water temperature, the atmospheric temperature, the displacement θ of the accelerator pedal, etc.
When ideally set according to the rotational speed n of the crankshaft 1a, the fuel consumption rate or exhaust gas components of the diesel engine 1 can be optimized, and for this purpose,
Among these relationships, for example, the target rotational phase angle pe ₀ to be set by the injection timing adjustment device 2 in the relationship between the displacement θ of the accelerator pedal and the rotational speed n of the crankshaft 1a is stored in the memory 5E as shown in FIG. It is stored in a map state like this.

In addition, each + mark in FIG. 5 is p ₃₃ , p ₃₄ ,
As shown in p ₄₃ and p ₄₄ , each target rotational phase angle corresponding to the relationship between the displacement θ of each accelerator pedal and the rotational speed n of the crankshaft 1a is stored at equal intervals, and these are Values that change according to changes in temperature are stored.

In addition, in FIG. 5, the electromagnetic pick-up 5H
Actual operating point p determined by the rotational speed n found from and the displacement θ of the accelerator pedal at that time.
The target rotational phase angle peo is determined by the target rotational phase angles p ₃₃ , p ₃₄ , p ₄₃ and p ₄₄ of the state in the vicinity e of point p, and the vicinity e is enlarged and shown in FIG.

In FIG. 4, Ld and dL are the displacement differences of the accelerator pedal, nd and dn each indicate the rotation difference, and the target rotational phase angle peo at point p is calculated in the central processing circuit 5B using the following formula. ing.

peo={(A-B)dn/nd}+B ……(3) However, A={(p ₄₄ −p ₃₄ )dL/Ld}+p ₃₄ ……(4) B={(p ₄₃ −p ₃₃ ) dL/Ld}+p ₃₃ (5) Note that all of the above equations (1) to (5) are stored in the memory 5E.

The target rotational phase angle peo obtained from the above equation (3) is compared with the actual rotational phase angle pe obtained from the equation (1), and based on the comparison, the central processing circuit 5B performs a calculation. However, when the microcomputer 5 operates the solenoid valve 5F using the calculation result, the following points must be taken into consideration.

That is, when the hydraulic oil in the hydraulic pump device 3 is in a considerably low temperature state in a cold region, etc., as described above, the viscosity of the hydraulic oil increases, and the flow from the pipe 3b to the solenoid valve 5F and the pipe Road 5n
Also, the responsiveness of the hydraulic control system leading to the injection timing adjustment device 2 (including the hydraulic actuator) has become slow.

Also, especially in such low temperature hydraulic fluids,
In the initial state when the switch is turned on to start control, since the load setting state is unstable as described above, the target rotational phase angle peo as the result of the above calculation is different from the actual one. The deviation from the rotational phase angle pe is often very large in its initial state.

This becomes an important problem in devices that need to quickly establish an appropriate control state in such an initial state.

To explain this problem in the case of the embodiment of the present invention, when the automobile engine is warming up after starting, the optimization of the injection timing of the fuel injection pump 4 becomes slow, and the engine stops flowing. worsens the exhaust components of
Moreover, the fuel efficiency will also deteriorate.

For this reason, at the beginning of the control according to the present invention, the following step control calculations are performed using the calculation results.

Step 1) Turn on the control circuit Step 2) Find the difference between the hydraulic oil temperature α in the hydraulic pump device 3 and the oil temperature α1 stored and set in the memory 5E.

Step 3) Find peo−pe=Er (deviation).

Step 4) Determine whether the absolute value of the deviation Er is larger or smaller than the absolute value of the minimum standard deviation Ero stored in the memory.

Step 5) If the judgment in step 4) is large and α-α1 in step 2) is negative, the absolute value of the deviation Er is equal to the minimum standard deviation Ero.
The microcomputer 5 continues to send a control signal to the electric wire 5k, which remains on, until the absolute value of .

With the above control signals, the solenoid valve 5 in FIG.
F operates in one direction, and as a result, the pressure oil from the hydraulic pump device 3 continues to operate the hydraulic actuator in the injection timing adjustment device 2 in one direction, and this continuous signal operation causes the fuel injection pump 4 to This will continue until the injection timing is first optimized.

As mentioned above, when the first period from steps 1) to 5) is completed, the load setting is maintained properly, or due to subsequent changes in load conditions, the deviation Er becomes the minimum standard deviation. If the temperature of the hydraulic fluid in the hydraulic control system is still lower than the predetermined temperature, the control calculation for the second period described below is performed, and the calculation step is step 6. ) Determine whether the difference α-α2 between the hydraulic oil temperature α in the hydraulic pump device 3 and the predetermined set temperature α2 stored in the memory 5E is positive or negative.

Step 7) Make the determination in step 4).

Step 8) When the judgment result in step 7) is large and α-α2 is negative, a control signal on the side of the sign of the deviation Er is applied to the wire 5k in a stepwise manner, and the stepwise application time ts is as follows: As shown in the characteristics shown in FIG. 7, it has a component that is inversely proportional to the hydraulic oil temperature α.

While the above operation is being performed, the hydraulic oil temperature α increases due to the work of the operation or as the temperature in the engine room increases, and the oil temperature α rises to the set temperature α2 at step 6). When the temperature becomes higher, the normal control process in the third period is entered.

In the third period, the digital pulse-like control signal given to the electric wire 5k is
The relationship between ts and deviation Er has the characteristics shown in FIG.

In addition, in FIG. 8, the characteristics on the right side of the ts axis indicate the application time of the signal applied to the electric wire 5k ₁ in FIG. ₂ indicates the application time of the signal given, and tso indicates the intersection of the ts axis and the gradient of each solid line.

The control calculation steps in the third period in the central processing circuit 5B will be explained below.

Step 9) Find peo−pe=Er.

Step 10) Store the absolute value of the deviation Er in memory 5E.
Compare with the respective absolute values of the minimum standard deviation Er ₀ and maximum standard deviation Er ₁ stored in .

Step 11) When the absolute value of the deviation Er is smaller than the absolute value of the minimum standard deviation _Er0 , the voltage value of the instruction signal is set to zero.

Step 12) The absolute value of deviation Er is the minimum standard deviation
Greater than the absolute value of Ero and the maximum standard deviation
When Er is smaller than ₁ , the central processing circuit 5B determines the sign of the deviation Er, and when the deviation Er is positive, it is given as one instruction signal to the electric wire 5k ₁ in Fig. 3, and the deviation Er is negative. If so, this is given to the aforementioned electric wire _5k2 as the other instruction signal. At this time, the application time of the pulse signal in one instruction signal or the other instruction signal is the application time proportional to the deviation Er, respectively.
It has a waveform pulse width with the addition of the minimum application time tso in FIG.

Step 13) When the absolute value of the deviation Er is greater than the absolute value of the maximum standard deviation Er ₁ , the electric wire 5k ₁ or 5k ₂ is continues to output instruction signals.

The instruction signal characteristics resulting from the above calculation are as shown in FIG.

In addition, in Fig. 9, the upper pulse is connected to the electric wire 5k ₁ ,
The lower side is given to the wire 5k ₂ .

What is important here is that in calculation step 12) in the third period, the application time of the instruction signal output when the deviation Er occurs is longer than the basic minimum application time tso, which is the application time proportional to the deviation Er. The point is that it is added.

This means that when such a deviation occurs, in order to correct the deviation, the set value of the load is converged within the target tolerance by the first pulse instruction signal for the deviation. It means that it is aimed at.

In order to achieve such a purpose, we experimentally determined in advance, for each magnitude of deviation, the application time of the instruction signal that corresponds to the amount of time the instruction signal is applied to bring those deviations within the allowable range with one instruction signal. The length has been determined, and the application time determined experimentally corresponds to the application time in step 12) above.

Therefore, the correction control of the deviation by the calculation step 12) is designed to bring about a control within or near the allowable deviation by issuing only one instruction signal for the deviation. It is something.

In addition, in the explanation in FIG. 3 above,
It has been explained that the electric wire 5k in Fig. 1 consists of the electric wires 5k ₁ and 5k ₂ , but this configuration is
k as a single wire, one indicating signal as a positive voltage and the other indicating signal as a negative voltage, which is applied to a single wire 5k, which wire 5k is connected on one side to the output interface 5D ₁ . , the other may be configured to be connected to the output interface 5D ₂ (the same circuit as 5D ₁ ) on the other side described above via a code converter. in this case,
The effect is similar to that described above.

Note that the control at the second period in the above embodiment is not necessarily necessary. This is the transmission of the second instruction signal following the first, and even if the temperature of the pressure oil at that time is below the predetermined temperature, the control is controlled by the first control in the first period. is almost in a predetermined control state, and the subsequent control can be performed normally even if the pressure oil temperature is low and the response speed is slow to some extent. However, by performing the second period control, it becomes possible to operate the engine 1 more effectively.

As is clear from the above description, the effects of the present invention are as follows.

Unlike the conventional method of continuing to output the instruction signal until the deviation becomes zero, after the detection of the deviation Er is completed, based on the detected deviation value Er, A method is adopted in which an instruction signal is output for an application time ts that is enough to correct the value of the deviation Er to exactly zero, that is, an application time ts that is the minimum application time tso plus an application time proportional to the deviation Er at that time. There is. Therefore, the deviation Er is corrected to a value of almost zero by only one pulse of the instruction signal in that control cycle.

Therefore, the response of the control becomes very quick, and the number of signal transmissions applied to the solenoid valve is reduced, so that the durability of the solenoid valve is improved.

Furthermore, in the control of the present invention, if the temperature of the pressure oil is below a predetermined temperature when issuing the first instruction signal, the application of the first instruction signal is continued until the deviation is corrected to within the allowable deviation. It is characterized by leaving it on. Therefore, it is possible to quickly set the proper start state of the control for the initially undetermined load setting state, compared to the usual method that outputs several separated pulse signals. .

Moreover, in that case, as described above, as a result of continuing to output the first instruction signal until the deviation falls within the allowable value, the solenoid valve in the control system will close after the instruction signal disappears due to the response delay. However, the pressure oil temperature in that state is extremely low,
Since the responsiveness of the control is very slow, the result of the control does not significantly overshoot.

Furthermore, in addition to the first invention, when the next instruction signal is transmitted following the first instruction signal and the temperature of the pressure oil is below a predetermined second temperature, the instruction signal is transmitted. When making the application time for each pulse have a time width of a component inversely proportional to the value of the pressure oil temperature, the control response speed should be kept constant until the original pressure oil temperature rises to the normal range. It is possible to make it similar.

As a result, the hydraulic actuator control method of the present invention does not require an oil temperature control device that is expensive, large, and increases energy consumption, and also does not require warming or controlling the oil temperature before starting control. It doesn't require a lot of idle time.

[Brief explanation of the drawing]

FIG. 1 shows a system diagram when the hydraulic actuator control method of the present invention is used in a fuel injection timing adjustment device 2 of a diesel engine 1, and FIG. 2 shows block lines of the input interface 5A in FIG. Figure 3 shows the first
One of the output interfaces 5D in the figure is shown by a circuit diagram, and FIG. ₄ is an enlarged view of the neighborhood e in FIG. 5, and FIG. pedal θ
A map digitally showing the target rotational phase angle of the fuel injection pump determined by the relationship between n and engine rotational speed n. FIG. 6 shows that the signals 5as and 5bs detected by the electromagnetic pickups 5G and 5H in FIG. 1 from the top, and the respective signals 5as and 5bs in the Schmitt circuit 5AB of FIG.
The characteristics of the rectangular wave signals 5ap and 5bp are shown. FIG. 7 shows the characteristics of the relationship between the pulse application time ts of the control signal output to the electric wire 5k shown in FIG. 1 and the hydraulic oil temperature α in the hydraulic control system during the second period of control, Figure 8 shows the pulse application time ts and the deviation Er from the control target value in the third period of control (normal time).
FIG. 9 shows the characteristics of the control signal V in the operating state appearing on the electric wire 5k in FIG. 1, in accordance with the characteristics in FIG. 8. The symbols used in the examples are as follows.
1: Diesel engine, 1a: Crankshaft, 1
b: disk, 1c: gear. 2: Injection timing adjustment device,
2a: input shaft, 2b: output shaft, 2c: gear. 3:
Hydraulic pump device, 3a: gear, 3b: piping. 4:
Fuel injection pump, 4a: disc. 5: Microcomputer, 5A: Input interface, 5
AB: Schmitt circuit, 5AD: Analog multiplexer, 5AE: A-D converter, 5B:
Central processing circuit, 5D: Output interface, 5
D ₁ : One output interface, 5E: Memory, 5F: Solenoid valve, 5F ₁ : One solenoid,
5G and 5H: Electromagnetic pick-up. 5a, 5
b, 5c, 5d, 5e, 5f, 5g, 5h, 5
j, 5k, 5k ₁ , 5m, 5p, 5q, 5r, 5
s, 5t, 5u and 5v: electric wire, 5n: piping,
5as, 5bs, 5ap and 5bp: signal. sa, sa′,
sb, pa ₁ , pa ₁ ′, pa ₂ and pb: pulse signal, t ₁ and t ₂ : measurement time, θ: accelerator pedal displacement,
n: rotation speed of diesel engine 1, p ₃₃ ,
p ₃₄ , p ₄₃ and p ₄₄ : target rotation phase angle in injection timing adjustment device 2, Ld and dL: displacement difference, dn and nd: rotation difference, p: actual operating point, d: reference voltage,
a, b and c: points, R ₁ , R ₂ and R ₃ : resistors,
TR ₁ and TR ₂ : Transistor, D: Diode, ts: Application time of the square wave voltage applied to the electric wire 5k, Er: Deviation between the target rotational phase angle and the actual rotational phase angle for the injection timing adjustment device 2, Er ₀ : Minimum standard deviation, Er ₁ : Maximum standard deviation, tso: Virtual minimum application time.

Claims (1)

[Claims] 1. Application of a single on-state instruction signal causes a solenoid valve to remain open during the application, and the opening applies pressure to a hydraulic actuator. The load is operated by force-feeding oil, and the application of the instruction signal is: a; the deviation value between the detected value of the set value set at the load and the target set value to be set for the load; b; Compare the absolute value of the deviation value with the absolute value of the minimum standard deviation value; c; When the absolute value of the deviation value is smaller than the absolute value of the minimum standard deviation value, the instruction The value of the signal is set to zero, and d; When the absolute value of the deviation value is greater than the absolute value of the minimum standard deviation value, the instruction signal is determined by determining the sign of the deviation value. sorting into one instruction signal or the other instruction signal, e; the application time of the classified instruction signal is
The relationship is such that the application time is the sum of the minimum application time and the application time proportional to the absolute value of the deviation value, and for the first instruction signal that transmits the above instruction signal, the temperature of the pressure oil is A method for controlling a hydraulic actuator, characterized in that when the temperature is below a predetermined temperature, application of the first instruction signal is kept on until the deviation is corrected to within an allowable deviation. 2. Application of a single on-state instruction signal causes the solenoid valve to remain open for the duration of the application, causing the hydraulic actuator to pump pressure oil to operate the load. , the application of the instruction signal is performed by: a; calculating the deviation value between the detected value of the setting value set at the load and the target setting value to be set for the load; and b; calculating the deviation value. and the absolute value of the minimum standard deviation value, c; When the absolute value of the deviation value is smaller than the absolute value of the minimum standard deviation value, the value of the instruction signal is set to zero, d ; When the absolute value of the deviation value is larger than the absolute value of the minimum standard deviation value, the instruction signal is determined as one instruction signal or the other instruction signal by determining the sign of the deviation value. e; the application time of the classified instruction signals is
The relationship is such that the application time is the sum of the minimum application time and the application time proportional to the absolute value of the deviation value, and for the first instruction signal that transmits the above instruction signal, the temperature of the pressure oil is If the temperature is below a predetermined first temperature, the application of the first indication signal is left on until the deviation is corrected within an acceptable deviation, and following the first indication signal, the next indication is applied. When transmitting a signal, when the temperature of the pressure oil is below a predetermined second temperature, the application time of each pulse in the instruction signal is a component inversely proportional to the value of the oil temperature. A method for controlling a hydraulic actuator, characterized in that the control method has a time width of .