JPH0470903A - Load controller - Google Patents

Abstract

PURPOSE:To quickly change the control duty of the load and to improve the responsiveness by producing a duty control signal to discriminate the levels at a prescribed level for drive control of the load and outputting the duty control signal of the corresponding duty. CONSTITUTION:A load controller 21 detects through a timer circuit 44 whether the cycle of a duty signal is shorter than a prescribed time T21 or not when a motor 23 is driven by a duty control signal of a cycle T24 shorter than the cycle T22 of the duty signal led out of an internal combustion engine controller 22. If the cycle of the duty signal is put shorter than the time 21, a duty control signal corresponding to the duty of the duty signal is outputted. If so, a duty control signal of 100% duty is outputted. That is, the duty signal is inverted at the time shorter than the time T21 when a sudden rise is required to the control duty of the motor 23 owing to detection of the sudden acceleration of the controller 22, etc. Thus the duty of the duty control signal is quickly changed and the delay of response can be reduced.

Description

[Detailed Description of the Invention] Overview In a load control device that performs duty control on loads such as motors and solenoid valves, a period in which a duty signal input via a communication line is at one level is measured, and the time period is handled accordingly. Based on the level, the signal level changes periodically, such as a triangular wave or a sine wave, by level discrimination.
A duty control signal for the load I\ is created. Further, when it is detected that the duty signal has reached a predetermined period, the discrimination level is set to a predetermined value, and a duty control signal of, for example, 100% is created.

By setting the predetermined period shorter than the period in which the timekeeping operation is performed, the control state in which the load is controlled by the duty in response to the normal duty signal is changed to the control state in which the load is controlled by the duty in response to the normal duty signal.
This makes it possible to quickly switch to a 0% control state.

INDUSTRIAL APPLICATION FIELD The present invention is suitably implemented as a load control device for duty-controlling a fuel pump of an internal combustion engine. The present invention relates to a load control device that drives a load using a control signal.

Prior Art FIG. 5 is a block diagram showing the electrical configuration of a typical prior art load control device 1. This control device 1 outputs a duty control signal to a motor 3 of a fuel pump, which is a load, in response to a duty signal from an internal combustion engine control device 2. The internal combustion engine control device 2 calculates the fuel injection amount and ignition timing based on detection results such as the intake pressure, the rotational speed of the internal combustion engine, and the cooling water temperature, and controls the fuel injection amount and ignition timing to actuators (not shown) such as fuel injection valves and igniters. In order to derive the output and control the drive of the motor 3, the method shown in FIG.
) is derived on line 11.

The control device 1 includes a counter 4, a comparator 5, and an oscillator 6. The counter 4 is reset when the duty signal rises, measures the period during which the duty signal is at a high level, and records the measurement result. A DC voltage level corresponding to the voltage level is derived to the comparator 5.

The comparator 5 is also provided with an output from an oscillator 6 as shown in FIG. 6(2), such as a triangular wave or a sawtooth wave whose signal level changes periodically. Comparator 5 level-discriminates the output from oscillator 6 based on the DC voltage level from counter 4, and outputs an output corresponding to the discrimination result to motor 3 via line 12 as a duty control signal.

A microcomputer 7 is provided within the control device 1 for calculating control amounts for the actuator, motor 3, and the like. This microcomputer 7 creates the duty signal by interrupt calculation processing and outputs it to the line 11 from the output terminal. The frequency of the duty signal thus created is determined by the number of loads to be controlled and the processing capacity of the microcomputer 7, and is, for example, 20 Hz.

Further, the microcomputer 7 is provided with a terminal exclusively for duty control output, from which a duty signal of a relatively high frequency, for example, 100 to 200 Hz can be output.

However, this dedicated terminal is used for other actuators such as the fuel injection valve and igniter.

On the other hand, the oscillator 6 generates an oscillation signal having a frequency sufficiently higher than that of the duty signal, for example, 20 KHz, in order to eliminate the effects of the back electromotive force of the motor 3 and the inertia of the fuel pump and the motor 3. a signal is given,
This oscillation signal is level-discriminated based on the DC voltage level output from the counter 4, and a duty control signal as shown in FIG. 6(3) is created.

Therefore, as shown in section W1 in FIG. 6, the tutee signal remains at a high level, and
When the 0 ro duty is displayed, the DC voltage level from the counter 4 becomes OV, and therefore the duty control signal remains at a high level, resulting in a 100% duty.

In addition, when the duty signal represents a duty control state in which the high level and the low level are periodically repeated, as shown by the section W2, the pulse period shown by the reference mark T1 in FIG. Corresponding to the duty determined from the pulse width indicated by T2, the DC voltage level is set as indicated by reference symbol 1 in FIG. 6(2). Therefore, the pulse width T4 of the duty control signal satisfies the first formula when the oscillation period of the oscillator 6 is represented by T3, corresponding to the duty of the duty signal.

Furthermore, as shown in section W3, when the duty signal represents 0% duty while remaining at a low level, the DC voltage level from the counter 4 is as shown in FIG. 6(2).
As shown by reference numeral 2, the duty control signal becomes high level, and therefore the duty control signal remains at low level with a duty of 0%.

In this way, the motor 3 is driven and controlled by a duty control signal having a duty equal to the duty signal derived to the line 11 and having a sufficiently higher frequency than the duty signal.

FIG. 7 is a diagram showing a fuel supply path for the internal combustion engine. When the motor 3 is driven to rotate, the fuel pump 11 pumps up fuel from the fuel tank 13 through the pipe line 12.
Discharge to 4. A fuel injection valve 15 is provided in the pipe line 14 , and this fuel injection valve 15 injects the fuel into the combustion air passing through the intake pipe 16 , and the air-fuel mixture thus created flows through the intake pipe 17 . Supplied to each combustion chamber.

A pressure regulating valve 18 is provided downstream of the fuel injection valve 15 in the pipe line 14, and the pressure regulating valve 18 maintains the fuel pressure in the pipe line 14 at a constant pressure of, for example, 5 kgf. . The excess fuel at the pressure regulating valve 18 is
The fuel is returned to the fuel tank 1B'\ via the pipe line 19.

Therefore, the fuel supplied to the fuel injection valve 15 depends on the number of revolutions per unit time of the fuel pump 11, that is, the number of revolutions per unit time of the fuel pump 11,
It corresponds to the control duty of

Problems to be Solved by the Invention In the control device 1 configured as described above, the frequency of the duty signal output from the control device 2 is set to 20H.
z, in order for the control device 1 to detect the duty of the duty signal, 1/20 (5ee) -5()
(msec) is required.

On the other hand, for example, when the internal combustion engine is rotating at 250 Orpm, the fuel injection valve 15 outputs, for example, 10 m5e.
Fuel injection is performed every c. Therefore, the time required to determine the duty of the duty signal is longer than the fuel injection period. For this reason, for example, in an internal combustion engine equipped with a supercharger, the air-fuel ratio of the air-fuel mixture supplied to the internal combustion engine becomes lean during acceleration in a high rotation range, and sufficient acceleration cannot be achieved.

On the other hand, if the motor 3 is always driven at a high duty, the life of the motor 3 will be shortened.

An object of the present invention is to promptly change the duty of the duty control signal when the duty of the duty signal does not switch to a predetermined duty when driving a load with a duty control signal having a higher frequency than the frequency of the input duty signal. It is an object of the present invention to provide a load control device that can change the response time and reduce response delay.

Means for Solving the Problems The present invention provides a load control device that outputs a duty control signal in response to a duty signal input via a communication line and performs duty control on a load. a timekeeping means that performs a timekeeping operation on the second level and outputs a first control signal having a level corresponding to the timekeeping result when the other level is reached;

a cycle detection means for detecting the cycle of the duty signal and outputting a second control signal when the detected cycle is a predetermined cycle; a signal generation source for deriving pressure whose signal level changes periodically; in response to the first and second control signals, when the second control signal is input, level-discriminates the output from the signal generation source at a predetermined discrimination level to create a duty control signal to the load; A load control device comprising: level discrimination means for level discriminating the output from the signal generation source to create the duty control signal based on the level of the first control signal when no signal is input. It is.

Function According to the present invention, a duty control signal is output in response to a duty signal inputted from an arithmetic processing device or the like via a communication line, and a load such as a motor is driven and controlled. The duty signal is input to a clocking means, and the clocking means performs a timing operation during a period when the duty signal is at one level, for example, a high level, and when the duty signal is at the other level, that is, a low level, the clocking means performs a timing operation when the duty signal is at the other level, that is, a low level. 1 control signal is output to the level discrimination means f\. That is, this clock means detects the duty of the duty signal.

The duty signal is also given to a cycle detection means, and the cycle detection means detects the cycle of the duty signal, and the detected cycle is a predetermined cycle that is sufficiently shorter than, for example, during normal duty control of the load. Sometimes, for example, it is determined that the duty signal represents 100% duty, and a second control signal is output to the level discrimination means.

The level discriminator is supplied with an output from a signal generation source whose signal level changes periodically, such as a triangular wave or a sawtooth wave, and whose frequency is sufficiently higher than that of the duty signal. The level discrimination means outputs the output from the signal generation source at a predetermined discrimination level, for example, 0 level, when the second control signal is input, that is, when the duty signal representing the 100% duty is input. The level is discriminated and a corresponding duty, ie, 100% duty control signal is created and output to the load.

Also, 3F to which the second control signal is not input! 1. During normal duty control, the level discriminator discriminates the level of the output from the signal generation source based on the signal level of the first control signal, and selects a duty corresponding to the duty signal and sufficiently higher than the frequency of the duty signal. Creates a frequency duty control signal and outputs it to the load.

Therefore, even when driving and controlling a load with a duty control signal having a frequency sufficiently higher than the frequency of the input duty signal, even if the duty signal changes to represent a predetermined duty, for example, 100%, the duty is quickly adjusted. In response to the change, the load can be driven and controlled at the predetermined duty.

Embodiment FIG. 1 is a block diagram showing the electrical configuration of a load control device 21 according to an embodiment of the present invention. This load control device 21
is a communication line fl from the internal combustion engine control device 22.
In response to the duty signal inputted through the line 112, a duty control signal having a frequency sufficiently higher than that of the duty signal is derived to the line 112, and the motor 23, which is the load, is duty-controlled.

The motor 23 drives the fuel pump 11 shown in FIG. 7 above. A microcomputer 40 is provided in the internal combustion engine control device 22, and this microcomputer 40 operates based on the intake pressure, the rotational speed of the internal combustion engine, and the cooling water temperature detected by various sensors 24. Then, the fuel injection amount and ignition timing are calculated, and actuators 26 such as fuel injection valves and igniters are driven and controlled via the output interface circuit 25.

The microcomputer 40 also controls the opening and closing of the relay 27 in response to the detection result of the sensor 24, and
A duty signal is output to the load control device 21 via the line /11. One terminal of a relay coil 28 of the relay 27 is connected to a battery 29, and the other terminal is connected to the internal combustion engine control device 22. When the relay coil 28 is energized, the power from the two batteries is
The actuator 26 via the relay switch 30
It is also supplied to the switching element 31 in the load control device 21.

Power from two batteries is supplied to one contact of the switching element 31 via the relay switch 30,
The other contact is connected to the motor 23. This switching element 31 is controlled to be conductive/blocked in response to a duty control signal via the line 112, and thus the motor 23 is duty controlled.

The load control device 21 measures the period during which the duty signal derived from the line 111 is at a high level, that is, the duty, and includes a duty measuring section 32 serving as a timekeeping means;
a periodic measuring section 33 that measures the period of the duty signal; an oscillating section 34 that derives an output whose signal level changes periodically at a frequency sufficiently higher than that of the duty signal; and an oscillating section 34 that is a signal generation source; and a duty set section 35 which is a level discrimination means for level discriminating the oscillation signal of the oscillation section 34 in response to the measurement results of the sections 32 and 33 and outputting a duty and iυ control signal to the line f12. It is configured.

FIG. 2 is a block diagram showing a specific configuration of the load control device 21. As shown in FIG. The duty signal via the line 111 is applied to one input of the AND gate 41,
A first clock signal from a clock signal generation circuit 42 is input to the other input of the AND gate 41.

Therefore, the AND gate 41 outputs a pulse responsive to the forward bending first clock signal and supplies it to the counter 43 during the period when the duty signal is at a high level. counter 4
3 is reset at the rising timing of the duty signal, and then performs a counting operation in response to a pulse from the AND gate 41.

The duty signal is also given to a timer circuit 44, and after being reset at the rise timing of the duty signal, the timer circuit 44 responds to the clock signal and starts a predetermined time T21, for example, 2 m.
A timing operation is performed for 5ec.

A high-level output is derived from the timer circuit 44 when the timer circuit 44 is performing the time-measuring operation, and a low-level output is derived when the timer circuit 44 has finished the time-measuring operation.

The counter 43 outputs the period T of the duty signal.
22 and the period T23 of the first clock signal. The output of the counter 43 is an OR game provided for the number of bits) Al, A2 . ..., A
n (hereinafter collectively referred to as reference numeral A) are input to one input terminal. The output from the timer circuit 44 is commonly applied to the other input terminals of these AND gates A.

The output from each AND gate A is the discrimination level setting circuit 45.
The discrimination level setting circuit 45 holds the output from each OR gate A when the duty signal falls from high level to low level, and determines the discrimination level.

The discrimination level setting circuit 45 also includes a timer circuit 49.
This timer circuit 49 is reset at the fall of the duty signal and starts timing operation, and when the duty signal is at a low level for a predetermined time or more, the timer circuit 49 is given an output from the discrimination level setting circuit 45. Derive the output.

The discrimination level setting circuit 45 responds to the output and determines a discrimination level for setting the duty of the duty control signal outputted from the comparison circuit 46 to 50%. The discrimination level thus determined is input to the comparison circuit 46 as serial data.

The count value of the counter 47 is also input to the comparison circuit 46 . The counter 47 performs a counting operation in response to the second clock signal from the clock signal generating circuit 48, and is reset every cycle T24 which is sufficiently shorter than the cycle T22 of the duty signal.

When the count value of the counter 47 is larger than the discrimination level set by the discrimination level setting circuit 45, the comparison circuit 46 outputs a high level output to the line 112, and thus the motor 23 is duty-controlled.

In the load control device 21 configured as described above, the line 111 is connected from the internal combustion engine control device 22 to a relatively long cycle T22, for example, 50 vasec, that is, the frequency is 20Hz, as shown in FIG. 3(1). A duty signal of is output. At time tll, which is the rise timing of this duty signal, the counter 43 is reset, and the counter 43 performs a counting operation as shown in FIG. 3(2) in response to the first clock signal whose period 723 is, for example, every lvAsec. . Also at this time tll
The timer circuit 44 is reset in FIG. 3(3).
Derive the high-level output as shown in .

Therefore, from time t12 when time T21 has elapsed from time tll, the count result of the counter 43 is input to the discrimination level setting circuit 45, and the count result is
As shown in FIG. 3(4), the discrimination level is set in the discrimination level setting circuit 45 at time t13 when the duty signal falls to a low level.

On the other hand, as shown in FIG. 4(1), the counter 47 is
A counting operation is performed in response to a second tarlock signal having a cycle T25 sufficiently shorter than the cycle T2B of the first clock signal, for example, 1 μsec, and is reset every cycle T24 determined corresponding to the cycle T22, for example, every 50 μS. Ru. The comparison circuit 46 derives a high level output when the count value of the counter 47 is equal to or higher than the discrimination level Vl1 set by the discrimination level setting circuit 45, as shown in FIG. 4(2).

Therefore, when the duty signal is at a high level beyond the set time T21 of the timer circuit 44, the comparator circuit 46 calculates, in accordance with the proportion of the period T26 in which the duty signal is at a high level per cycle T22, The duty control signal of the duty equal to the duty of the duty signal is set so that the ratio of the period T27 during which the output of the comparator circuit 46 is at a high level to the reset period T24 of the counter 47 is equal to the duty of the duty signal.
Output to 21.

In this way, as shown by section w11 in FIG. 3, a period T during which the input duty signal is at a high level
26 is longer than the clock operation time T21 of the timer circuit 44, it is possible to output a duty control signal having a duty equal to the input duty signal and having a frequency sufficiently higher than that of the input duty signal.

On the other hand, as shown in section W12, time t2
1, the counter 43 and the timer circuit 44 are reset, and at time t23 before time t22 when the time T21 has elapsed from this time t21, when the duty signal is switched to low level, the output from the timer circuit 44 is As shown in FIG. 3(3), it is maintained at a high level, and thereby the discrimination level set by the discrimination level setting circuit 45 becomes 0 level. Therefore, as shown in FIG. 4(2), the comparator circuit 46 outputs a duty control signal that remains at a high level, that is, has a duty of 100%.

As described above, in the load control device 21 according to the present invention, the period T of the duty signal derived from the internal combustion engine control device 22 is
When driving the motor 23 with a duty control signal having a cycle T24 shorter than 22, the timer circuit 44 predetermines the cycle of the duty signal at a time ra! 721 or less, and if not, outputs a duty control signal corresponding to the duty of the duty signal, and if so, outputs a duty control signal with a 100% duty.

Therefore, when it becomes necessary to rapidly increase the control duty of the motor 23, such as when the internal combustion engine control device 22 detects that sudden acceleration is to be performed, the duty signal may be inverted within the time 721. Such control can be easily realized, for example, by inverting the output level of the output terminal each time the microcomputer 40 performs main arithmetic processing, without adding a large burden to the software.

Therefore, the line lil is connected to the microcomputer 4.
0 general output terminal, thereby making it possible to effectively utilize the dedicated terminal for other purposes without using the dedicated duty control output terminal of the microcomputer 40.

Further, the change to 100% duty of the motor 23 can be detected in a sufficiently shorter time than the cycle T22 of the duty signal, and when the internal combustion engine accelerates, the pipe to the fuel injection valve 15 shown in FIG. Sufficient fuel pressure can be maintained in the passage 14, and acceleration performance can be improved. Furthermore, since the motor 23 is driven with a low control duty during steady operation, it is possible to extend the life of the motor 23 and the fuel pump 11.

Effects of the Invention As described above, according to the present invention, when the period of the duty signal input via the communication line is a predetermined period, the output from the signal generation source whose signal level changes periodically is predetermined. A duty control signal for driving and controlling a load is generated by level discrimination based on the discrimination level, and when the cycle is not a predetermined cycle, a duty control signal of a duty corresponding to the duty of the duty signal is output. Even if the frequency of the output duty control signal is sufficiently higher than that of the input duty signal, if the duty signal does not switch to a predetermined duty, for example 100%, the load control duty can be changed quickly. Responsiveness can be improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the electrical configuration of a load control device 21 according to an embodiment of the present invention, FIG. 2 is a block diagram showing a specific configuration of the load control device 21, and FIGS. A waveform diagram for explaining the operation of the control device 21, FIG. 5 is a block diagram showing the electrical configuration of the conventional load control device 1, and FIG. 6 is a waveform diagram for explaining the operation of the load control device 1. , FIG. 7 is a diagram for explaining the fuel supply path of the internal combustion engine. 11... fuel pump, 15... fuel injection valve, 21...
・Load control device, 22・Internal combustion engine control device, 23 Motor, 3 switching element, 32・Duty measurement unit, 3
3... Period measurement section, 34... Oscillation section, 35... Duty set section, 40... Microcomputer, 43
．． 47...Counter, 44.49-Timer circuit, 45
...Discrimination level setting circuit, 46...Comparison circuit Agent Patent attorney Kei Saikyo Figure 4 Figure 4

Claims (1)

[Scope of Claims] A load control device that outputs a duty control signal in response to a duty signal input via a communication line, and performs duty control on a load, comprising: performing a timing operation during a period when the duty signal is at one level; , a timing means for outputting a first control signal at a level corresponding to the timing result when the other level is reached, and a period for detecting the cycle of the duty signal and outputting a second control signal when the detected cycle is a predetermined cycle. a detection means; a signal generation source that derives an output whose signal level changes periodically; and a signal generation source that responds to the first and second control signals and outputs the signal at a predetermined discrimination level when the second control signal is input. A duty control signal to the load is created by level-discriminating the output from the signal generation source, and when the second control signal is not input, the output from the signal generation source is level-discriminated based on the level of the first control signal. and a level discriminator for discriminating and creating the duty control signal.