JPS62224783A - Solenoid control circuit - Google Patents

Abstract

PURPOSE:To enable control of a valve for controlling warming-up running even under a sever temperature condition, by providing a Joule heat generating means, which is attached in a hot-combining state to a positive characteristics thermistor, connected in series to a solenoid. CONSTITUTION:A resistor R, forming a solenoid circuit, and a circuit, e.g., a positive characteristics thermistor PHI, a constant voltage circuit IC, a diode D, are mounted to the same printed substrate. The resistor R is a printed resistor for generating a Joule heat, connected in parallel to a solenoid L. The Joule heat generating mean increases the temperature of a substrate by means of a Joule heat, and further, enables increase of the temperature of the positive characteristics thermistor PHI connected in series to the solenoid L, controlling opening and closing of a valve.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a solenoid control circuit disposed in the engine room of an automobile and used for controlling driving when driving an automobile engine in cold weather. It is related to.

[Conventional technology] As a conventional technology for the control circuit of this type of solenoid valve,
1-53313 can be mentioned.

The above technology includes a temperature-sensitive valve that controls the opening degree of an intake passage of an automobile engine in an auxiliary manner to a throttle valve, a first electric circuit that heats the temperature-sensitive valve with a high-temperature heater when the circuit is opened, and a first electrical circuit that heats the temperature-sensitive valve with a high temperature heater when the circuit is opened. a second electric circuit that heats the temperature-sensitive valve with a low-temperature heater; and an atmospheric temperature switch that closes the first electric circuit when the atmosphere is below a predetermined temperature and opens the second electric circuit when the atmosphere is above a predetermined temperature. The system is characterized in that each set of heaters is controlled according to the atmospheric temperature.

That is, in the above technology, the atmospheric temperature under which the engine is placed is set to an arbitrary temperature, and the open state of the bypass passage of the intake passage of the engine is divided into two depending on whether the temperature is above or below the set temperature.
It changes in stages.

[Problems to be Solved by the Invention] However, when warming up an automobile engine in cold weather, it is ideal to make the warming-up time inversely proportional to the cooling temperature of the engine. Therefore, by performing two-stage control at a predetermined temperature as in the conventional example and changing the fuel supply at the time of engine startup, the warm-up operation of the engine does not necessarily match the temperature conditions. Ta. One possible solution to this problem is to use a positive temperature coefficient thermistor to control the current of the solenoid valve by the self-heating of the positive coefficient thermistor. However, the self-heating of the positive temperature coefficient thermistor limits the current of the solenoid valve! 21I
In this case, at an environmental temperature below a predetermined temperature, the internal resistance of the PTC thermistor is small and less Joule heat is generated. There may be cases in which the point where the resistance value suddenly changes cannot be obtained. In other words, in cold regions with severe temperature conditions, it will become uncontrollable.

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention aims to provide a solenoid control circuit that is capable of controlling even under severe temperature conditions.

[Means for Solving the Problems] The solenoid control circuit according to the present invention includes a positive temperature coefficient thermistor that is connected in series with a solenoid that controls the opening and closing of a warm-up control valve and that performs control based on its temperature characteristics, and the substrate. It consists of a Joule heat generating means attached to the top of the PTC thermistor in a thermally coupled state and increasing the resistance value as the temperature rises.

[Operation 1] In the solenoid control circuit of the present invention, the positive characteristic thermistor that performs solenoid control that opens and closes the warm-up control valve according to temperature characteristics is operated at an environmental temperature lower than the Curie point temperature, and at a temperature that is lower than the Curie temperature. When the difference from the Curie point temperature is large, the self-heating amount of the PTC thermistor is small because the resistance value of the PTC thermistor itself is small.

Therefore, the positive temperature coefficient thermistor connected in series with the solenoid that controls the opening and closing of the valve does not generate enough Joule heat to change its internal resistance, making it difficult to control the current of the solenoid that controls the opening and closing of the valve.

At this time, the Joule heat generating means connected in series with the PTC thermistor mounted on the board on which the PTC thermistor is mounted raises the temperature of the board by generating Joule heat, and further controls the opening and closing of the valve. The temperature of a positive temperature coefficient thermistor connected in series with a solenoid can be increased.For example, if the heat generated by a positive coefficient thermistor connected in series with a solenoid that controls the opening and closing of a valve is in thermal equilibrium with the environmental temperature. However, thermal equilibrium can be overcome by other sources of Joule heat.

[Embodiment] FIG. 1 shows a solenoid control circuit according to a first embodiment of the present invention. The warm-up operation control valve controlled by the solenoid 1III111 circuit is constructed as shown in the sectional view of FIG. 2.

First, the warm-up operation control valve shown in FIG. 2 will be explained.

In the figure, a warm-up operation control valve 1 has a solenoid L wound around a non-magnetic resin bobbin 2, a resin cover 4 fixed to the bobbin 2, and a center hole of the bobbin 2.
A fixed iron core 5 and a movable iron core 6 are arranged.

The resin cover 4 has a printed circuit board 1 on top thereof.
2 is accommodated, and the accommodated space is filled with epoxy resin. As shown in FIG. 4, the control circuit for the warm-up operation control valve mounted on the printed circuit board 12 includes a resistor R and a positive temperature coefficient thermistor PH1 that constitute a solenoid control circuit.
, a constant voltage circuit IC, a diode D, and other circuits are assembled on the same printed circuit board 12, and the solenoid boards are electrically connected by a connecting piece 14.

In the above configuration, when the solenoid L is energized, magnetic flux is generated in the magnetic circuit consisting of the fixed iron core 5, the movable iron core 6, and the yoke 7, and an attractive force is generated between the movable iron core 6 and the fixed iron core 5, and the movable iron core 6 is attracted to the fixed iron core 5 against the biasing force of the spring 8. As a result, the inlet 9 communicating with the intake manifold is communicated with the outlet 10 communicating with the negative pressure operated valve, and communication between the atmospheric passage 11 and the outlet 10 is cut off.

When the solenoid L is de-energized, the biasing force of the spring 8 between the movable iron core 6 and the fixed iron core 5 causes the inlet 9 communicating with the intique manifold and the outlet 10 communicating with the negative pressure operated valve to be shut off. Thus, the air passage 11 and the outlet 10 are brought into a conductive state.

Next, a first embodiment of the solenoid control circuit of the present invention will be described.

In the figure, the resistance value of the positive characteristic thermistor PH1 rapidly increases as the temperature rises, as shown in the resistance-temperature characteristic diagram of FIG. In addition, the solenoid is wound around a non-magnetic bobbin 2 that constitutes the warm-up operation control valve 1 shown in FIG. Move 6. The resistor R is a printed resistor for generating Joule heat connected in parallel with the solenoid. The constant voltage circuit IC is commercially available as a known integrated circuit for constant voltage circuits. Diode D is for preventing reverse connection.

The circuit is connected to an ignition switch SW and receives power from a power source E.

The solenoid control circuit configured as described above can operate as follows.

When the atmosphere starts an internal combustion engine under certain temperature conditions,
First, turn on the ignition switch SW. When the internal combustion engine is in a cooled state, the positive characteristic thermistor P
The internal resistance of H1 is small, and the solenoid L of the warm-up operation control valve 1 is excited by the current from the power source E. As a result, the movable core 6 is attracted to the fixed core 5 against the biasing force of the spring 8, and the inlet 9 communicating with the intique manifold is connected to the outlet 10 communicating with the negative pressure operated valve.
The communication between the atmospheric passage 11 and the outlet 10 is cut off.

Therefore, when starting the internal combustion engine, the air-fuel ratio is reduced by the warm-up operation control valve 1, which is independent of the throttle valve.

The temperature of the positive characteristic thermistor PH1 starts from the temperature condition under which the internal combustion engine is started, and the temperature rises due to self-heating of the internal resistance. When the temperature of positive temperature coefficient thermistor PH1 increases,
The resistance value of the internal resistance increases, increasing the voltage drop due to the internal resistance.

When the resistance value reaches 0, the current of the solenoid L of the warm-up operation control valve 1 is decreased, and the movable iron core 6 is sucked by the solenoid L of the warm-up operation control valve 1. The force becomes smaller than the biasing force of the spring 8, and the warm-up operation control valve 1 closes the inlet 9 communicating with the intique manifold, and the outlet 10 communicating with the negative pressure operating valve and the atmospheric passage 11 are brought into communication with each other. Increase the air-fuel ratio.

At this time, when the internal resistance increases due to self-heating of the PTC thermistor Pl-11, when the environmental temperature is low and below the thermal equilibrium state, the self-heating of the PTC thermistor Pl-11 reaches the Curie point temperature. I can't do it, but
The smaller the resistance value of the resistance R of the positive temperature coefficient thermistor PH1, the more Joule heat is generated.
The resistor R can raise the temperature of 1 and escape from the thermal equilibrium state.

Therefore, the characteristics at this time are as shown in the characteristic diagram of FIG. 5, and if the warm-up of the internal combustion engine matches the operating characteristics, the startability of the engine can be improved.

FIG. 6 is a solenoid control circuit diagram of a warm-up operation control valve according to a second embodiment of the present invention.

In the figure, the positive characteristic thermistor PH1, solenoid, ignition switch SW, and electric current are the same components as in the first embodiment shown in FIG. 1, and their explanation will be omitted. In particular, only the differences between this embodiment and the first embodiment will be explained. Note that the constant voltage circuit IC and the diode D for preventing reverse connection are not directly related to the gist of the present invention, and therefore will be omitted in the following embodiments.

The positive characteristic thermistor PH2 replaces the resistor R in the first embodiment. In the solenoid control circuit of this example,
The positive temperature coefficient thermistor P)-12, which is thermally coupled to the positive temperature coefficient thermistor PH1, has the same function as that of the first embodiment,
Furthermore, due to the self-heating of the positive temperature coefficient thermistor P H2,
The power consumption can be reduced. In particular, two positive thermistors PH1 and PH2 are connected in series.
Since the positive temperature coefficient thermistor PH1 and the positive coefficient thermistor PH2 are in a stage, it is possible to suppress wasteful power consumption as much as possible after the positive temperature coefficient thermistor PH1 and the positive coefficient thermistor PH2 reach one Curie point or more.

In addition, since the power consumption of the positive characteristic thermistor PH2 can be reduced by self-heating, the solenoid control circuit diagram of the warm-up operation control valve according to the third embodiment of the present invention shown in FIG. The characteristic thermistor PH2 may be connected to the power supply side and connected in parallel to the series circuit of the positive characteristic thermistor PH1 and the solenoid L.

FIG. 8 is a solenoid control circuit diagram of a warm-up operation control valve according to a fourth embodiment of the present invention.

In the figure, positive characteristic thermistor PH1, positive characteristic thermistor PH2, solenoid L1, ignition switch S
The W1 power supply E is connected to the
The components are the same as those in the embodiment, the second embodiment, and the third embodiment, and their explanation will be omitted. In particular, only the differences between this embodiment and the first embodiment will be explained.

The positive characteristic thermistor PH2 is connected in series with the resistor R of the first embodiment. In the solenoid control circuit of this embodiment, the resistance R thermally coupled to the positive temperature coefficient thermistor PH1 is
The function is similar to that of the first embodiment, and furthermore, due to the self-heating of the positive temperature coefficient thermistor P H2 connected in series with the resistor R, it is possible to cause the resistor R to generate Joule heat only at a predetermined temperature or lower. can. Therefore, power-saving control according to the environmental temperature is possible. In this embodiment, a positive characteristic thermistor PH1 and a positive characteristic thermistor P l-
(Since 2 is included in two stages, positive characteristic thermistor PH1
And the positive temperature coefficient thermistor PH2 can suppress wasteful power consumption as much as possible after the temperature reaches one point or more.

In addition, since the power consumption of the positive temperature coefficient thermistor PH2 can be reduced by self-heating, the solenoid control circuit diagram of the warm-up operation control valve according to the fifth embodiment of the present invention shown in FIG. The characteristic thermistor PH2 and the series resistor R may be connected to the power supply side, and the positive characteristic thermistor PH1 and the solenoid may be connected in parallel to any series circuit.

In other embodiments other than the first embodiment described above, a solenoid L that controls the opening and closing of the warm-up operation control valve 1, and a positive characteristic thermistor PH1 that is connected in series with the solenoid and performs control based on its temperature characteristics. , a substrate 12 on which the positive temperature coefficient thermistor is mounted, and a substrate 12 mounted on the substrate 12;
Positive characteristic thermistor PH2 or positive characteristic thermistor PH
Joule heat generating means is used which increases the resistance value as the temperature increases.

The solenoid control circuit of the first embodiment includes a positive characteristic thermistor PH2 connected in series with the resistor R of the fourth embodiment shown in FIG. This is the same as the positive temperature coefficient thermistor PH1.

In each of the embodiments described above, the current of the solenoid L is directly controlled by the positive temperature coefficient thermistor PH1, but a circuit using an active element such as a transistor may also be used. Also,
The same applies to the positive temperature coefficient thermistor PH2.

[Advantageous Effects of the Invention 1] As described above, the solenoid control circuit of the present invention includes a positive temperature coefficient thermistor that is connected in series to a solenoid that controls opening and closing of a warm-up control valve and that performs control based on its temperature characteristics, and a positive temperature coefficient thermistor that is mounted on the substrate. The joule heat generating means is installed in a thermally coupled state with the positive temperature coefficient thermistor and increases the resistance value as the temperature rises. For example, the heat generated by a positive thermistor connected in series to a solenoid that controls the opening and closing of a valve will reach thermal equilibrium with the environmental temperature. Even in this case, thermal equilibrium can be overcome by other sources of Joule heat generation.

Therefore, it is possible to control the Nada operation control valve even under severe temperature conditions.

[Brief explanation of drawings]

FIG. 1 is a solenoid control circuit diagram of a first embodiment of the present invention;
Fig. 2 is a sectional view of the heating valve used in the above embodiment, Fig. 3 is a characteristic diagram of the positive temperature coefficient thermistor, and Fig. 4 is an assembled state of the solenoid control circuit of the first embodiment of the present invention. FIG. 5 is a characteristic diagram of a solenoid control circuit according to the first embodiment of the present invention, FIG. 6 is a solenoid control circuit diagram of a warm-up operation control valve according to a second embodiment of the present invention, and FIG. The figure is a solenoid control circuit diagram of a warm-up operation control valve according to a third embodiment of the present invention, FIG. 8 is a solenoid control circuit diagram of a warm-up operation control valve according to a fourth embodiment of the present invention, and FIG. A solenoid control circuit diagram of a warm-up operation control valve according to a fifth embodiment of the present invention, and FIG. 10 is a characteristic diagram of a conventional solenoid control circuit. In the figure, 1...Warm-up operation control valve, 2...Solenoid, R...Resistor, PL-11, PH1...Positive characteristic thermistor. In addition, in the figures, the same reference numerals and the same symbols do not indicate the same or equivalent parts.

Claims (5)

[Claims] (1) A solenoid that controls opening and closing of a warm-up operation control valve, a positive temperature coefficient thermistor that is connected in series with the solenoid and performs control based on its temperature characteristics, a board on which the positive coefficient thermistor is mounted, and a board on which the positive temperature coefficient thermistor is mounted. A solenoid control circuit comprising: Joule heat generating means that is attached in a thermally coupled state with the positive temperature coefficient thermistor and increases the resistance value as the temperature rises. (2) The solenoid control circuit according to claim 1, wherein the Joule heat generating means is constituted by a resistor. (3) The solenoid control circuit according to claim 1, wherein the Joule heat generating means is constituted by a positive temperature coefficient thermistor. (4) The solenoid control circuit according to claim 1, wherein the Joule heat generating means is constituted by a resistor connected in series with a positive temperature coefficient thermistor. (5) A positive temperature coefficient thermistor connected in series with the resistor of the Joule heat generating means and a positive coefficient thermistor connected in series with the solenoid and controlling according to its temperature characteristics are common. The solenoid control circuit according to item 4.