JPH0314110B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for a plurality of solenoid valves, more specifically, a solenoid valve having a solenoid coil for opening a valve and a solenoid coil for closing a valve, particularly a 2-port 2-position solenoid switching valve. For example, a device that sequentially controls multiple electromagnetic switching valves used as fuel valve actuators that drive the fuel injection valves installed in each cylinder of a diesel engine in a predetermined order. It relates to a device to be controlled.

A solenoid valve, typically a 2-port, 2-position solenoid switching valve, is equipped with a valve-closing spring that keeps the valve always closed and a valve-opening solenoid coil that opens the valve against the force of this spring. Some solenoid valves are equipped with a solenoid coil for opening a valve and a solenoid coil for closing a valve, and both opening and closing of the valve are driven using a solenoid (this is called a double solenoid solenoid valve).

The time required to close a solenoid valve equipped with a valve-closing spring is determined by the force of the valve-closing spring, which is set to be weaker than the force generated by the valve-opening solenoid coil. A problem with valves is that the time required to close the valve is inevitably longer than the time required to open the valve. On the other hand, in a double solenoid electromagnetic valve, a solenoid is used to open and close the valve, so there is a possibility that its operation can be made faster. Control of this double solenoid electromagnetic valve includes voltage control in which a step voltage is applied to the solenoid coil, and current control in which a step current is applied. The current flowing through the coil is an integral waveform of the voltage applied to the coil, so in voltage control, the rise of the current flowing through the solenoid coil is slow.
Significant delays in valve response occur. In current control,
The current flowing through the solenoid coil is controlled so that its rise and fall are steep, and the voltage has a differential waveform of the current, so the response is fast, and current control is suitable for high-speed control of solenoid valves.

On the other hand, optimal control of internal combustion engines, such as diesel engines, using computers has recently been developed. This detects the diesel engine's crank angle, rotational speed, torque, pressure and temperature of various parts of the engine, concentration of exhaust gas, etc., inputs this data into a computer, and uses the computer to determine the optimal control of the diesel engine. Let the conditions be calculated. The calculation result is then output as control command information, and based on this command information, the starting valve, intake valve, exhaust valve, fuel injection valve, etc. are controlled according to the crank angle. Electromagnetic valves are often used for the actuators of these valves, especially the fuel injection valves. Since diesel engines rotate at high speeds, solenoid valves as actuators are also required to be controlled at high speeds. Furthermore, since a diesel engine has multiple cylinders, multiple solenoid valves are provided as actuators for each cylinder's fuel injection valve, and are sequentially controlled according to the crank angle. Ru.

As a control device that controls multiple solenoid valves in a diesel engine, etc. in a fixed order.
For example, the one described in Japanese Patent Application Laid-Open No. 50-47018 is known.

However, in the case of such conventional control devices,
The opening solenoid coil and closing solenoid coil of each solenoid valve are controlled independently, and only a step signal is applied to each solenoid coil, so switching the solenoid valve open and close is easy. It cannot be made very fast, and diesel
It is not always possible to control the engine optimally.

The present invention provides control of a plurality of solenoid valves that enables high-speed control of a plurality of solenoid valves in a certain order, and enables optimal control of devices in which the solenoid valves are used, such as diesel engines. The purpose is to provide equipment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to optimal control of a diesel engine will be described in detail below with reference to the drawings.

FIG. 1 shows the entire control system for a diesel engine. A diesel engine 10 is provided with a plurality of cylinders 11. The number of cylinders 11 is N (for example, 12), and numbers are assigned from No. 1 to No. N. Each cylinder 11 is equipped with a starting valve 21, an intake valve 22, a fuel injection valve 23, and an exhaust valve 24, and each of these valves 21-
24 are provided with actuators 25 to 28 for operating them. fuel injection valve 2
3 is supplied with fuel oil from a fuel oil tank 30 by a pump 29.

The rotation angle of the crankshaft of the diesel engine 10 is detected by an encoder 12, and is sent to the central processing unit (hereinafter referred to as CPU) via an input port 14.
31 and is also sent to the diesel engine control circuit 16. The output of the encoder 12 is also sent to the F/V converter 13, where it is converted into a voltage signal representing the rotational speed, and then input to the CPU 31 via the A/D converter 15. These sensors also detect the pressure and temperature of each part of the diesel engine, the concentration of exhaust gas components, etc.
The data is converted into a digital signal by the A/D converter 15 and then input to the CPU 31.

The CPU 31 reads the operation commands input from the various setting input display device 32, and based on the operation commands, the crank angle, rotation speed, torque, etc. of the diesel engine input from the A/D converter 15, etc., and each part of the engine are read. Using data representing the operating state of the engine, such as the pressure and temperature of the diesel engine and the concentration of exhaust gas components, the system calculates the control variables and operating variables for optimal control of the diesel engine, according to a predetermined program. Then, from this calculation result, a control command for the fuel oil pump 29 is created and output to the pump 29 via the D/A converter 19, as well as controlling control valves such as the starting valve, intake valve, fuel injection valve, and exhaust valve. A command is created and output to the diesel engine control circuit 16.

The diesel engine control circuit 16 is a CPU
The control commands from the fuel valve actuator drive circuit 1 are stored, and the control information is sent to the fuel valve actuator drive circuit 1 according to the crank angle input from the encoder 12.
7, and the starting valve, intake valve and exhaust valve actuator drive circuit 18. Drive circuit 18
is the actuator 2 of each control valve 21, 22, 24
5, 26, and 28. Details of the drive circuit 17 and actuator 27 are shown in FIG.

Figure 3 shows the schematic configuration of a double solenoid solenoid valve, and Figure 4 shows the response of the position of the valve closing member in the solenoid valve when the solenoid coil of this solenoid valve is controlled by current. There is. When a step-shaped excitation current IA is applied to the opening solenoid coil 1A of a double solenoid solenoid valve, the force generated from the solenoid coil 1A moves the valve closing member to the opening position, and the solenoid valve opens. be done. When the energization to the solenoid coil 1A is stopped and the step-shaped excitation current IB is applied to the valve-closing solenoid coil 1B, the valve-closing member moves to the valve-closing position and the solenoid valve is closed. The response of the position P of the valve closing member is determined by a solenoid valve with a built-in valve closing spring,
Much faster than voltage controlled double solenoid solenoid valve, but with some delay t1N,
There is T1F. The time t1N required to open the valve and the time t1F required to close the valve are approximately equal.

Since the double solenoid electromagnetic valve operates as the fuel valve actuator 27, the same number n of this electromagnetic valve as the cylinders 11 are provided. A solenoid valve drive circuit 50 is provided for each of the double solenoid solenoid valves. In Figure 2, a solenoid coil 1A for opening and a solenoid coil 1B for closing a double solenoid solenoid valve.
are connected in series. Solenoid coil 1A has valve closing switching transistor 2B.
However, valve opening switching transistors 2A are connected in parallel to each solenoid coil 1B.

The excitation current control circuit that controls the excitation current flowing through the solenoid coil 1A or 1B is composed of a current adjustment circuit 4 and a current detection resistor 8 connected between the solenoid coil 1B and the ground. , a power transistor 5 connected between the drive power supply VP and the solenoid coil 1A, and an operational amplifier 6 for controlling the base voltage of the transistor 5. A voltage signal for controlling the excitation current is inputted to the non-inverting input terminal of the operational amplifier 6 from an analog switch 48, which will be described later, and a voltage drop due to the excitation current of the resistor 8 is inputted to the inverting input terminal. Diodes 55, 56, and 57 connected in parallel to transistors 5, 2B, and 2A, respectively, are protection diodes for preventing reverse voltage from being applied to these transistors. A capacitor 9 connected to the non-inverting input terminal of the operational amplifier 6 is used to prevent the voltage at this input terminal from momentarily becoming unstable when the analog switch 48 is switched. .

A voltage corresponding to the difference between the voltages input to both input terminals of the operational amplifier 6 appears at the output terminal of the amplifier 6, and the transistor 5 is analog-controlled by this differential voltage. As a result, the excitation current of the solenoid coil is controlled so that the voltage difference mentioned above becomes zero, that is, so that the voltage drop across the resistor 8 becomes equal to the output voltage of the analog switch 48.

The valve open signal and the valve close signal are output from the output terminals Q and Q of the flip-flop 49, respectively, and these signals are sent to the photo couplers 3B and 3A, respectively. Photo couplers 3A and 3B are each composed of light emitting diodes 35A and 35B and photo transistors 36A and 36B. An appropriate operating voltage is applied to the anodes of the light emitting diodes 35A and 35B via the current control resistor 7, and their cathodes are connected to the output terminal Q of the flip-flop 49, respectively. Photo transistors 36A and 36B are connected in a Darlington type to switching transistors 2A and 2B, respectively.

When flip-flop 49 is set, its output Q goes to H level and its output goes to L level.
Since the output Q is at H level, the light emitting diode 3
Since no current flows through 5B and it does not emit light, no photo
Transistor 36B and switching transistor 2B are both off. As a result of the flip-flop 49 output becoming L level, the photo
A current flows through the light emitting diode 35A of the coupler 3A, and this diode 35A emits light. Therefore, both photo transistor 36A and switching transistor 2A are turned on. Since transistor 2B is turned off and transistor 2A is turned on, the energizing current flows through power transistor 5, solenoid coil 1A and transistor 2A, and solenoid coil 1A is energized, so that the solenoid valve opens. Needless to say, since the transistor 2A is on, no exciting current flows through the solenoid coil 1B.

When the flip-flop 49 is reset, the output Q becomes L level and the output becomes H level. Therefore, the light emitting diode 35A no longer emits light,
Photo transistor 36A and transistor 2A are turned off. Then, since the light emitting diode 35B of the photo coupler 3B emits light, the photo transistor 36B and the transistor 2B are turned on. As a result, the excitation current flows through transistor 5, transistor 2B, and solenoid coil 1B, so that solenoid coil 1B is energized and solenoid coil 1A is deenergized. The solenoid valve is therefore closed. Solenoid coil 1 when opening or closing the solenoid valve
Needless to say, the excitation current flowing through A or 1B is controlled in accordance with the output voltage of the analog switch 48 by the above-mentioned excitation current control circuit.

Referring to Figures 2 and 5, the diesel
The engine control circuit 16 outputs excitation current waveform data, data specifying the solenoid valves to be controlled, and valve opening and closing commands for the N solenoid valves in accordance with the crank angle signal, and registers 41 and 41, respectively. 42 and 43 and are temporarily stored. The excitation current waveform data in the register 41 is sequentially converted into an analog current signal by a D/A converter 44 and sent to an amplifier 45 as an excitation current waveform signal. This amplifier 45 is an isolation amplifier including an element such as a photo coupler or a transistor that electrically isolates the input side and the output side. The output voltage signal of amplifier 45 is sent to one input terminal a of analog switch 48.
The other input terminal b of this analog switch 48
A constant voltage set by a potentiometer 51 is applied to.

The solenoid valve specification data in the register 42 is sent to the decoder 4.
Sent to 6. On the N output lines of the decoder 46, when a solenoid valve connected to that line is designated, an L level designation signal appears for the designated period. Each output line of the decoder 46 is connected to the cathode of a light emitting diode of a photo coupler 47 provided correspondingly in each electromagnetic valve drive circuit. An appropriate operating voltage is applied to the anode of this light emitting diode via a current control resistor 52. The emitter of the phototransistor of the photocoupler 47 is grounded, and an operating voltage is applied to the collector via a pull-up resistor 53. Analog switch 48 is controlled by the collector voltage of this phototransistor.

When one of the outputs of the decoder 46 goes to L level, current flows through the light emitting diode of the corresponding photo coupler 47 and emits light, which turns on the photo transistor and turns on the analog switch 4.
8 receives an L level control signal. At this time, the analog switch 48 is connected to the input terminal a side, and the excitation current signal from the amplifier 45 is sent to the non-inverting input terminal of the operational amplifier 6 via the analog switch 48. During a period when the solenoid valve designation signal is at H level and the solenoid valve is not designated, the photo diode of the corresponding photo coupler 47 is off, so its collector voltage is at H level. At this time, the input terminal b of the analog switch 48 is connected, and the voltage set in the potentiometer 51 is applied to the non-inverting input terminal of the operational amplifier 6.

In the above description, each electromagnetic valve is designated by an L level designation signal, but it goes without saying that it can also be designated by an H level designation signal. In this case, the connection of the analog switch 48 may be switched to the terminal a when the collector voltage of the photo transistor of the photo coupler 47 is at H level.

Although there are N electromagnetic valves, only one D/A converter 44 and one decoder 46 are provided. This is a diesel engine 10
This is because the fuel injection periods in each cylinder 11 do not overlap in time. In a diesel engine with N≦12, that is, 12 cylinders or less, the fuel injection periods do not usually overlap, so one D/A converter 44 and one decoder 46 are often sufficient. Even if the fuel injection periods of two cylinders overlap, it will be sufficient to provide two sets of D/A converters and decoders.

The valve opening command and valve closing command from the register 43 are sent to the set input terminal s and the set input terminal R of each flip-flop 49 in synchronization with the designation of the solenoid valve by the decoder 46, respectively. As shown in FIG. 5, during one cycle of the crankshaft of the diesel engine 10 (360 degrees for a two-stroke diesel engine and 720 degrees for a four-stroke diesel engine), N solenoid valves are operated. They are specified one after another in a fixed order. During each specified period, the excitation current waveform signal contains two
Two triangular waveforms appear. Flip-flop 49 is reset when the corresponding solenoid valve is not designated. Then, during the period from peak to peak of the two triangular waveforms in the excitation current waveform signal (this becomes the fuel injection period), the flip-flop 49 corresponding to the designated solenoid valve is reversed to the set state twice.

When the flip-flop 49 is set, the solenoid coil 1A of the corresponding solenoid valve is energized and the solenoid valve is opened. Also, within this specified period, the excitation current of the solenoid coil is controlled by the excitation current waveform signal output from the amplifier 45. Therefore, the solenoid
The exciting current IA flowing through the coil 1A has a waveform that has peaks and steep rises and falls at the front and rear ends of the fuel injection period, and becomes zero approximately in the middle of this period. Furthermore, the excitation current IB flowing through the solenoid coil 1B exhibits a certain value approximately in the middle of the fuel injection period, becomes zero at the front and rear portions of this period, and further decreases outside the fuel injection period during the specified period. In the front and rear parts, the waveform shows steep falls and rises. Outside the specified period, the exciting current is controlled by the output voltage of the potentiometer 51, so the current IB flowing through the solenoid coil 1B remains constant.

The excitation current waveforms IA and IB shown in Fig. 5 were derived from the viewpoint of achieving optimal fuel injection valve control, which switches the solenoid valve open and close at a higher speed, increases the thermal efficiency of the diesel engine, and minimizes fuel consumption. This is an example of a waveform. Opening the solenoid valve twice within the fuel injection period has the effect of increasing the thermal efficiency of the diesel engine. Also, momentarily passing a large current when switching between opening and closing a solenoid valve is
This has the effect of increasing switching speed and keeping the amount of heat generated by the solenoid coil low. The times t2N and t2F required to open and close the valve are shorter than the times t1N and t1F when a step current as shown in FIG. 4 is applied. The amount of heat generated by a solenoid coil is determined by the integral value of the current flowing through it. Since the exciting current IA shown in FIG. 5 is zero in the middle of the fuel injection period, even if it shows a large value before and after that, its integral value can be used as the integral value of the step-like current IA shown in FIG. The values can be set to not much different values. Furthermore, after the valve closing member of the solenoid valve has moved to the valve closing position, the force necessary to hold the valve closing member in this position can be generated from the solenoid coil 1B.
The excitation current IB passed through can be kept at a very small value outside of the specified period.

It goes without saying that the excitation current waveform signal within the specified period of the electromagnetic valve is not limited to that shown in FIG. 5, but any waveform signal can be adopted.

In this embodiment, the main controller side including the CPU 31 and the drive circuit 50 side of each solenoid valve are electrically insulated by photo couplers 3A, 3B, 47 and an isolation amplifier 45. There is. Therefore, noise on the drive circuit 50 side is not transmitted to the main control device side, and noise resistance can be improved, malfunctions of the main control device can be prevented, and reliability can be improved. In addition, photo coupler 3
A, 3B, 47 and isolation amplifier 45 are driven by current or take a current signal as an input signal, and photo couplers 3A, 3B, flip-flop 49, photo coupler 47, decoder 46, amplifier 45 and D/ A current signal is transmitted on the signal line between the A converter 44 and the A converter 44 . Therefore, it is possible to extend these signal lines to a very long length, and the solenoid valve drive circuit side can be placed close to the solenoid valve, and the main control circuit can be placed far away from the solenoid valve.

FIG. 6 shows another embodiment. here,
Amplifier 45 and photo coupler 47 are not provided. Also, line drivers 60A, 60B are connected instead of photo couplers 3A, 3B. And line drivers 60A, 60
The transistor B is connected in a Darlington configuration to switching transistors 2A and 2B, respectively. Other configurations and operations are the same as those shown in FIG.

As described above in detail, the control device for a plurality of solenoid valves according to the present invention includes a solenoid valve drive circuit provided for each of the plurality of solenoid valves, a solenoid valve designation circuit that designates the solenoid valve to be controlled for a control period,
An excitation current waveform signal generation circuit that generates an excitation current waveform signal during a designated period for each solenoid valve, a constant excitation current value generation circuit that generates a constant excitation current value, and a solenoid valve designation circuit that is provided for each of the plurality of solenoid valves. Each electromagnetic valve drive circuit is composed of an excitation current signal selection circuit that selects either the output signal of the excitation current waveform signal generation circuit or the constant excitation current value generation circuit according to a specified signal, and each solenoid valve drive circuit is connected in series. A solenoid coil for opening and closing a solenoid valve, an excitation current control circuit that controls the excitation current flowing through the solenoid coil based on the output signal of the excitation current signal selection circuit, and each solenoid coil. The solenoid coil consists of two switching elements that are connected in parallel to each other and energize only one of the solenoid coils in response to a valve opening command or a valve closing command.

Therefore, a plurality of solenoid valves can be sequentially controlled in accordance with the designation by the solenoid valve designation circuit.

The solenoid valve drive circuit is provided with an excitation current control circuit that controls the excitation current flowing through the solenoid coil of the solenoid valve based on the output signal of the selection circuit. It is now possible to control the waveform generated by the waveform signal generation circuit to any desired waveform.
The present invention can be applied to various devices, such as the control of fuel injection valves in diesel engines, and by optimally determining the excitation current waveform, these devices can be optimally controlled.

Furthermore, in the solenoid valve drive circuit, the solenoid coil for opening the solenoid valve and the solenoid coil for closing the solenoid valve
The solenoid coils are connected in series, and a switching element is connected to these solenoid coils to energize only one of the solenoid coils in response to a valve open command or a valve close command. In addition to achieving valve opening/closing control in accordance with the valve closing command, switching of the excitation current by the switching element can be done instantaneously, and the rise and fall of the excitation current waveform of the solenoid coil can be made steep. - Combined with the fact that the exciting current flowing through the coil can be set to any waveform, the opening/closing switching of the solenoid valve can be made faster. The solenoid coils for opening and closing the valve are connected in series, so when switching, the electromagnetic energy stored in one excited solenoid coil is used as the excitation energy for the other solenoid coil. For this reason, effective use of electromagnetic energy is achieved, and the capacity of the solenoid drive power source can be reduced to achieve cost reduction.

[Brief explanation of drawings]

Figure 1 is a block diagram showing the entire diesel engine control system, Figure 2 is a block diagram showing the control circuit of the fuel valve actuator, Figure 3 is a block diagram of the double solenoid solenoid valve, and Figure 4 is the solenoid valve. FIG. 5 is a time chart showing the operation of the circuit shown in FIG. 2. FIG. 6 is a block diagram showing a modification. 1A... Valve opening solenoid coil, 1B...
Valve closing solenoid coil, 2A, 2B...Switching transistor, 4...Current adjustment circuit,
5... Power transistor, 6... Arithmetic amplifier, 8... Current detection resistor, 10... Diesel...
Engine, 11... Cylinder, 16... Diesel engine control circuit, 17... Fuel valve actuator drive circuit, 23... Fuel injection valve, 27...
Fuel valve actuator, 31...CPU, 41,
42, 43... Register, 44... D/A converter, 46... Decoder, 48... Analog switch, 49... Flip-flop, 50... Solenoid valve drive circuit, 51... Potentiometer.

Claims (1)

[Scope of Claims] 1. A solenoid valve drive circuit provided for each of a plurality of solenoid valves, a solenoid valve designation circuit that designates a solenoid valve to be controlled for a predetermined period, and an excitation current waveform signal for each solenoid valve during a designated period. An excitation current waveform signal generation circuit that generates a constant excitation current value, a constant excitation current value generation circuit that generates a constant excitation current value, and an excitation current waveform signal generation circuit that is provided for each of the plurality of solenoid valves and is activated by a designated signal of the solenoid valve designation circuit. Each solenoid valve drive circuit consists of a solenoid coil for opening the solenoid valve and a solenoid coil for closing the solenoid valve connected in series. An excitation current control circuit that controls the excitation current flowing through the solenoid coil based on the output signal of the excitation current signal selection circuit, and an excitation current control circuit that is connected in parallel to each solenoid coil to issue a valve opening or closing command. Only one solenoid coil is energized according to the valve command2
A control device for multiple solenoid valves consisting of one switching element.