JP7679112B2 - Heat source device using proportional solenoid valve, control method, program, recording medium, control device, and hot water supply device - Google Patents

Description

The present disclosure relates to, for example, a heat source device that uses a proportional solenoid valve to control fuel gas, a control method, a program, a control device, and a control technique for a hot water supply device.

A heat source device used in a hot water supply system that heats water to supply hot water uses a proportional valve that controls the supply amount of fuel gas according to the hot water demand. A proportional solenoid valve is known as this proportional valve, and controls the valve opening by exciting a proportional solenoid.
The opening degree of the proportional solenoid valve is controlled, for example, by a PWM (pulse width modulation) system.
Regarding the PWM control of this proportional solenoid valve, a control is known in which the period of dither vibration is increased or decreased in a suspension control device regardless of the magnitude of the current being supplied (Patent Document 1).

Japanese Patent Application Publication No. 10-258625

In a proportional solenoid valve, a difference occurs between the drive current when the drive current flowing through the solenoid is increased to reach a specific valve opening and the drive current when the drive current is decreased to reach a specific valve opening. Also, a difference occurs between the valve opening when the drive current is increased to reach a specific drive current and the valve opening when the drive current is decreased to reach a specific drive current. In other words, hysteresis exists between the drive current and the valve opening, and even with the same drive current, the valve opening differs depending on the direction of increase or decrease, and even with the same valve opening, a difference occurs in the drive current.

In a water heater using such a proportional solenoid valve for fuel control, there are problems such as changes in the combustion state, deviations in the outlet water temperature, and the time required for initial setup of the fuel control on the production line.
For example, some burners have two different burner sections, and can select a combustion mode in which only one burner section is burned when the demand for hot water is low (single-stage combustion), only the other burner section is burned when the demand for hot water is medium (two-stage combustion), and both burners are burned simultaneously when the demand for hot water increases (three-stage combustion). When fuel control is performed using a proportional solenoid valve to respond to such increases and decreases in the demand for hot water, hysteresis exists in each of the single-stage combustion, two-stage combustion, and three-stage combustion. This hysteresis causes differences in the valve opening with the same drive current, which causes differences in the CO and NOx values generated by combustion, that is, there is a problem that the combustion state changes. This change in the combustion state is significant in, for example, single-stage combustion, where the amount of combustion gas is small.
There is a problem in that the hysteresis characteristic affects the hot water outlet temperature, causing a discrepancy in the hot water outlet temperature relative to the hot water demand.
Furthermore, there is a problem in that setting the secondary pressure on the production line to reduce the effects of the hysteresis characteristics is time-consuming and requires a considerable amount of time.
The cause of this hysteresis is the magnetization characteristics of the proportional solenoid valve, particularly the residual magnetism. When using a magnetic material, the effect of this residual magnetism cannot be ignored.

When considering this magnetism and the excitation of the solenoid, there is an issue that when the proportional solenoid is excited in the same direction as the residual magnetism, the residual magnetism is added to the generated magnetic force, whereas when the proportional solenoid is excited in the opposite direction to the residual magnetism, part of the generated magnetic force is offset by the residual magnetism.
The inventor discovered that in order to address the issues associated with proportional solenoid valves for heat source devices, the effects of residual magnetism can be reduced by having the proportional solenoid generate an alternating magnetic field, and that even with a drive current that generates such an alternating magnetic field, the desired valve opening can be obtained by adjusting the level of the current.
In view of the above problems and findings, an object of the present disclosure is to improve the control characteristics in fuel control by reducing or avoiding the effect of residual magnetism on a proportional solenoid valve.

In order to achieve the above object, according to one aspect of a heat source device disclosed herein, there is provided a heat source device comprising: a burner that burns fuel gas; a proportional solenoid valve that is installed in a flow passage of the fuel gas and adjusts the fuel gas to the burner; a drive unit that generates a drive current and excites a proportional solenoid of the proportional solenoid valve with the drive current; and a valve element of the proportional solenoid valve that magnetizes a yoke and a movable magnetic pole to different magnetic poles by excitation of the proportional solenoid regardless of the flow direction of the drive current, and moves a valve element of the proportional solenoid valve by an attractive force of the magnetic poles generated in the movable magnetic pole and the yoke. and a control unit that reverses the polarity of the drive current at a period faster than the movement of the valve body to generate an alternating magnetic field and offset at least the residual magnetism of the movable magnetic pole , wherein the control unit comprises a logic circuit that generates a forward pulse including a polarity reversal section that reverses the polarity of the reverse direction drive current to a forward direction, and a reverse pulse that includes a polarity reversal section that reverses the polarity of the forward direction drive current to the reverse direction, and a pulse width control unit that controls the duty ratio of the forward pulse excluding the polarity reversal section or the duty ratio of the reverse pulse excluding the polarity reversal section .
This heat source device may further include a heat exchanger that exchanges the combustion heat of the fuel gas with a fluid to be heated, and a temperature sensor that detects the temperature of the heated fluid, and the control unit may change the current level of the drive current in accordance with the detected temperature of the heated fluid, and control the valve opening degree of the proportional solenoid valve .

In order to achieve the above object, according to one aspect of a control method of the present disclosure, a control method using a proportional solenoid valve to control fuel gas includes the steps of: generating a drive current that excites a proportional solenoid of the proportional solenoid valve; combusting the fuel gas that has passed through the proportional solenoid valve; magnetizing a yoke and a movable magnetic pole to different magnetic poles by exciting the proportional solenoid regardless of the flow direction of the drive current, moving a valve body of the proportional solenoid valve by an attractive force of the magnetic poles generated in the movable magnetic pole and the yoke, reversing the polarity of the drive current at a period faster than the movement of the valve body to generate an alternating magnetic field and offsetting residual magnetism of at least the movable magnetic pole; generating a forward pulse including a polarity reversal portion that reverses the polarity of the reverse drive current to a forward direction; generating a reverse pulse including a polarity reversal portion that reverses the polarity of the forward drive current to the reverse direction; controlling a duty ratio of the forward pulse excluding the polarity reversal portion; and controlling the duty ratio of the reverse pulse excluding the polarity reversal portion .
This control method may include a step of exchanging heat of combustion of the fuel gas with a heated fluid, and a step of detecting a temperature of the heated fluid, changing a current level of the drive current in accordance with the detected temperature of the heated fluid, and controlling a valve opening degree of the proportional solenoid valve .

In order to achieve the above object, according to one aspect of a program of the present disclosure, there is provided a program implemented by a computer, the program including: a function for generating control information for generating a drive current for exciting a proportional solenoid; a function for igniting a burner and burning a fuel gas that has passed through a proportional solenoid valve equipped with the proportional solenoid; and a function for magnetizing a yoke and a movable magnetic pole to different magnetic poles by exciting the proportional solenoid regardless of the flow direction of the drive current, and for moving a valve element of the proportional solenoid valve by an attractive force of the magnetic poles generated between the movable magnetic pole and the yoke. The computer realizes the following functions: a function of reversing the polarity of the drive current at a period faster than the movement of the valve body to generate an alternating magnetic field and offset at least the residual magnetism of the movable magnetic pole ; a function of generating a forward pulse including a polarity reversal section that reverses the polarity of the reverse direction drive current to a forward direction; a function of generating a reverse direction pulse including a polarity reversal section that reverses the polarity of the forward direction drive current to the reverse direction; a function of controlling the duty ratio of the forward pulse excluding the polarity reversal section; and a function of controlling the duty ratio of the reverse direction pulse excluding the polarity reversal section .
In order to achieve the above object, according to one aspect of a recording medium of the present disclosure, the program is stored therein.

In order to achieve the above object, according to one aspect of the control device of the present disclosure, there is provided a control device which generates a drive current for exciting a proportional solenoid which controls a valve opening degree by excitation, and flows the drive current through the proportional solenoid; ignites a burner, burns fuel gas which has passed through a proportional solenoid valve equipped with the proportional solenoid, magnetizes a yoke and a movable magnetic pole to different magnetic poles by excitation of the proportional solenoid regardless of the flow direction of the drive current, and moves a valve element of the proportional solenoid valve by an attractive force of the magnetic poles generated between the movable magnetic pole and the yoke. and a control unit that reverses the polarity of the drive current at a period faster than the movement of the valve body to generate an alternating magnetic field and offset at least the residual magnetism of the movable magnetic pole, wherein the control unit comprises a logic circuit that generates a forward pulse including a polarity reversal section that reverses the polarity of the reverse direction drive current to a forward direction, and a reverse pulse that includes a polarity reversal section that reverses the polarity of the forward direction drive current to the reverse direction, and a pulse width control unit that controls the duty ratio of the forward pulse excluding the polarity reversal section, or the duty ratio of the reverse pulse excluding the polarity reversal section .

In order to achieve the above-mentioned objective, according to one aspect of the water heating device disclosed herein, the heat source device, the control method, the program, the recording medium, or the control device is used to heat water and supply hot water at a hot water supply temperature heated to a set temperature.

According to the present disclosure, any of the following effects can be obtained.
(1) The effects of residual magnetism in the proportional solenoid valve can be reduced or avoided, and the difference in valve opening in response to the drive current in the increasing and decreasing current levels is small, preventing differences in the amount of fuel gas supplied in response to the drive current.
(2) Changes in the combustion state are suppressed, making it possible to obtain a stable combustion state.
(3) The difference in the temperature of the tap water when the fuel gas is increasing or decreasing can be prevented.
(4) In the production line, it becomes easier to set the secondary gas pressure after passing through the proportional solenoid valve.

1 is a diagram showing a water heating device according to a first embodiment; FIG. 3 is a cross-sectional end view of the valve unit taken along line III-III in FIG. 2. 4 is a cross-sectional end view of the valve unit taken along line IV-IV in FIG. 2. FIG. 11 is a diagram illustrating an operation of the valve unit. FIG. 11 is a diagram illustrating an operation of the valve unit. 4 is a flowchart showing hot water supply control. FIG. 2 illustrates a control system for a proportional solenoid valve. FIG. 2 is a diagram showing a valve mechanism of a proportional solenoid valve. FIG. 2 is a diagram showing a valve drive mechanism of a proportional solenoid valve. 4 is a flowchart showing the control of a proportional solenoid valve. 4 is a flowchart showing the control of a proportional solenoid valve. 11A and 11B are diagrams illustrating polarity inversion, level control, and generation of attraction force of a drive current by PWM control. FIG. 13 is a diagram showing a control system for a proportional solenoid valve according to a second embodiment. FIG. 13 is a diagram showing a valve unit and a control system according to a third embodiment. FIG. 13 is a diagram showing the output characteristics of a proportional solenoid valve by a drive current without polarity reversal. FIG. 4 is a diagram showing the output characteristics of a proportional solenoid valve due to a drive current with polarity reversal.

First Embodiment
Fig. 1 shows a water heater according to a first embodiment. The configuration shown in Fig. 1 is an example, and the present disclosure is not limited to such a configuration.
The water heater 2 is an example of a heat source device of the present disclosure. The water heater 2 includes a hot water supply port 6, a water supply port 8, a fuel gas port 10, a drain port 12, and an exhaust port 14 in a housing 4. The housing 4 is installed on, for example, a wall surface of a building.

The hot water supply port 6 is connected to a hot water supply pipe 16 that supplies hot water HW to the demand point. The water supply port 8 is connected to a water supply pipe 18, such as a water pipe (not shown), for supplying water W. The fuel gas port 10 is connected to a gas pipe 20 that supplies fuel gas G. The drain port 12 is used to discharge drain D generated by heat exchange of combustion heat. The exhaust port 14 discharges the combustion exhaust gas after heat exchange.

A combustion chamber 22 is installed in the center of the housing 4. A burner 24, an igniter 26, a spark plug 27, a flame rod 28, an air intake fan 30, a primary heat exchanger 32, a secondary heat exchanger 34, and a drain receiver 36 are installed in this combustion chamber 22. The burner 24, for example, has first and second burner sections 24-1 and 24-2 with different burner surfaces, and is capable of combustion only in the burner section 24-1, combustion only in the burner section 24-2, or simultaneous combustion in the burner sections 24-1 and 24-2. When a demand for hot water arises, the igniter 26 and the spark plug 27 ignite the fuel gas G in the burner 24, and the flame rod 28 detects the combustion of the fuel gas G in the burner 24.

The intake fan 30 draws combustion air into the combustion chamber 22 when the burner 24 is burning. The primary heat exchanger 32 exchanges heat between the feed water W and mainly the sensible heat of the upstream combustion exhaust gas, and heats the feed water W. The secondary heat exchanger 34 exchanges heat between the feed water W and mainly the latent heat of the downstream combustion exhaust gas, and heats the feed water W. This secondary heat exchanger 34 is installed upstream of the feed water W with respect to the primary heat exchanger 32, and is connected in series to the primary heat exchanger 32 by a connecting pipe 35. The drain receiver 36 receives the drain D generated by the heat exchange in the secondary heat exchanger 34, and leads to the drain tank 38. The drain D stored in the drain tank 38 leads to the drain port 12 through the drain discharge pipe 40.

The fuel gas G supplied to the fuel gas port 10 is guided from the gas supply pipe 42 to the valve unit 44, and then from the gas supply pipe 42-1 to the burner section 24-1 and from the gas supply pipe 42-2 to the burner section 24-2. The valve unit 44 has a main valve function that switches the fuel gas G between a supply state and a cut-off state, a proportional valve function that adjusts the supply of fuel gas G according to hot water demand, and a switching valve function that switches the supply of fuel gas G to the burner sections 24-1 and 24-2.

A water supply pipe 46 is provided between the water supply port 8 and the secondary heat exchanger 34 to supply water supply W to the secondary heat exchanger 34. A temperature sensor 48, a water volume sensor 50, and a mixed water control valve 52 are installed in this water supply pipe 46. The temperature sensor 48 detects the temperature of the water supply W. The water volume sensor 50 detects the amount of water flowing through the water supply pipe 46. The mixed water control valve 52 controls the mixing of the hot water HW heated in the primary heat exchanger 32 and secondary heat exchanger 34 with the water supply W.

Between the hot water supply port 6 and the primary heat exchanger 32, a hot water outlet pipe 54 is provided on the primary heat exchanger 32 side, and a hot water supply pipe 56 is provided on the hot water supply port 6 side. A temperature sensor 58 is installed in the hot water outlet pipe 54. A water control valve 60 is installed between the hot water outlet pipe 54 and the hot water supply pipe 56, and a bypass pipe 62 is connected between the water control valve 60 and the mixed water control valve 52. The water control valve 60 controls the amount of hot water HW that is output. A temperature sensor 64 is installed in the hot water supply pipe 56.

The detected water volume from the water volume sensor 50, the detected temperature representing the water supply temperature from the temperature sensor 48, the detected temperature representing the hot water outlet temperature from the temperature sensor 58, and the detected temperature representing the hot water supply temperature from the temperature sensor 64 are input to the control device 66. The control device 66 acquires this detection information and controls the amount of combustion gas using the valve unit 44, thereby realizing hot water supply at a hot water supply temperature controlled to the set temperature.

Figure 2 shows the front of the valve unit 44, Figure 3 shows a cut end surface taken along line III-III in Figure 2, and Figure 4 shows a cut end surface taken along line IV-IV in Figure 2. The configurations shown in Figures 2 to 4 are examples, and the present disclosure is not limited to such configurations.

This valve unit 44 has an inlet port 68 and first and second outlet ports 70-1 and 70-2 in a valve unit housing 67, with a solenoid valve 72 installed on the inlet port 68 side, a solenoid valve 74 installed on the outlet port 70-1 side, and a solenoid valve 76 installed on the outlet port 70-2 side, and a proportional solenoid valve 78 installed between the solenoid valve 72 and the solenoid valves 74 and 76.

As shown in FIG. 5, with this valve unit 44, when the solenoid valve 72 and one of the solenoid valves 74 are controlled to be open, the outlet port 70-1 is selected. In this state, when the valve opening of the proportional solenoid valve 78 is controlled, the amount of fuel gas discharged from the outlet port 70-1 is controlled.

Also, as shown in FIG. 6, the solenoid valve 72 and both solenoid valves 74 and 76 are controlled to be open, and both outlet ports 70-1 and 70-2 are selected. In this state, by controlling the valve opening of the proportional solenoid valve 78, the amount of fuel gas discharged from both outlet ports 70-1 and 70-2 is controlled.

<Hot water supply control>
7 shows the hot water supply control of the hot water supply device 2. The control process of this hot water supply control includes occurrence of hot water demand (S101), opening of electromagnetic valves 72, 74, 76 (S102), ignition of burner 24 (S103), control of the amount of fuel gas by the amount of water (S104), control of the hot water supply temperature to a set temperature (S105), determination of the end of the hot water supply demand (S106), closing of electromagnetic valves 72, 74, 76 (S107), extinguishing burner 24 (S108), and the like.

Occurrence of hot water demand (S101): A demand for hot water is generated by, for example, opening a hot water valve connected to the hot water supply pipe 16. This demand for hot water prompts the supply of water W from the water supply pipe 18. This supply of water W is detected by the water volume sensor 50, and the detection output of this water volume sensor 50 is input to the control device 66.

Opening the electromagnetic valves 72, 74, 76 (S102): In response to the occurrence of a demand for hot water, the control device 66 opens the electromagnetic valves 72, 74, 76. As a result, the fuel gas G flows to the burner 24.
Ignition of burner 24 (S103): When a demand for hot water is generated, the control device 66 activates the igniter 26 and ignites the burner 24 via the spark plug 27.

Control of fuel gas amount based on water amount (S104): The water amount detected by the water amount sensor 50, detection signals from the temperature sensor 48, etc. are input as a control signal for the fuel gas amount to the control device 66. The control device 66 controls the opening degree of the proportional solenoid valve 78 of the valve unit 44.
Control hot water temperature to set temperature (S105): The control device 66 can set a desired hot water temperature by initial setting or by the user. In response to the temperatures detected by the temperature sensors 48, 58, and 64 and the water volume detected by the water volume sensor 50, the control device 66 controls the hot water temperature to the set temperature and supplies hot water.

Determining the End of Hot Water Supply Demand (S106): The amount of hot water supply is detected by the water volume sensor 50, and the control device 66 determines the end of the hot water supply demand based on the water volume detected by the water volume sensor 50.
Closing the electromagnetic valves 72, 74, 76 (S107): When the demand for hot water supply ends, the control device 66 closes the electromagnetic valves 72, 74, 76. Therefore, the supply of the fuel gas G to the burner 24 is stopped.
Extinguishing the burner 24 (S108): The supply of fuel gas G to the burner 24 is stopped, and the burner 24 is extinguished.

Fig. 8 shows a control system 102 for the valve unit 44. In Fig. 8, the same parts as those in Figs. 2 to 6 are denoted by the same reference numerals.
In this control system 102, the proportional solenoid valve 78 is used for proportional control of the fuel gas G introduced into a passage 108. An inlet port 112-1 and an outlet port 112-2 are formed in a valve chest 110. The passage 108 is formed between the solenoid valve 72 and the solenoid valves 74, 76 (FIG. 4). The fuel gas G flowing into this passage 108 is guided from the inlet port 112-1 to the valve chest 110, passes through the valve mechanism 114 from the valve chest 110, and flows into the passage 108 from the outlet port 112-2.

The valve mechanism 114 includes a valve seat 116 and a valve body 118. The valve seat 116 is fixed to the wall surface of the valve chamber 110, and the valve body 118 moves in a direction perpendicular to the valve seat surface of the valve seat 116.
A diaphragm 124 is attached by a support member 122 to a shaft portion 120 formed on the central axis of the valve element 118. The outer edge of the diaphragm 124 is supported between the inner walls of the valve chamber 110. Therefore, the valve element 118 is supported by the diaphragm 124 so as to be able to move up and down in the valve chamber 110, and when the pressure of the fuel gas G acts on the inside of the valve chamber 110, the diaphragm 124 bulges and pulls the valve element 118 down.

A movable magnetic pole 126 is provided relative to the valve body 118, and this movable magnetic pole 126 is in contact with the shaft portion 120 of the valve body 118. In other words, the movable magnetic pole 126 constitutes a plunger. This movable magnetic pole 126 is inserted into a proportional solenoid 128 and can move in the central axis direction of the valve body 118. A yoke 132 is provided in the proportional solenoid 128 with a coil 130 sandwiched between them. The coil 130 is wound around a coil bobbin 134 and is provided in the proportional solenoid 128. Therefore, the yoke 132 constitutes a fixed magnetic pole relative to the movable magnetic pole 126.

A support frame 136 is fixed to the yoke 132 side, and a space 138 is formed in this support frame 136 to allow the diaphragm 124 to bulge. A support member 140 is fixed to the yoke 132, and this support member 140 has a spring support portion 142. A spring insertion portion 144 is formed in the movable magnetic pole 126, and a coil spring 146 is installed between this spring insertion portion 144 and the spring support portion 142. Therefore, the restoring force of the spring 146 acts on the movable magnetic pole 126.

The control device 66 includes, for example, a drive unit 148 and a control unit 150, and generates a drive current id, inverts the polarity, and controls the level. The drive unit 148 generates a drive current id under the control of the control unit 150, and passes this drive current id to the proportional solenoid 128. The control unit 150 includes, for example, a computer, and receives detection outputs from various sensors, such as a temperature sensor and a water volume sensor, as a control signal Sin, and performs information processing to control the proportional solenoid valve 78. This information processing includes:
(a) Control for generating driving current i
(b) Polarity reversal of the drive current id due to a period faster than the movement of the valve disc 118
(c) Control of the valve opening degree by the current level of the drive current id.

<Valve mechanism 114>
9 shows an enlarged view of the valve mechanism 114 of the proportional solenoid valve 78. The valve seat 116 is fixed to the valve chamber 110 by a retaining frame 151, and the gap between the valve seat 116 and the inner wall surface of the valve chamber 110 is sealed by an O-ring 152.
The valve body 118 has a conical surface portion 154, and this conical surface portion 154 and a valve opening portion 156 of the valve seat 116 perform a valve function.

In the valve chamber 110, facing the valve body 118, a circular recess 158, for example, is formed on the central axis of the valve body 118. Facing this recess 158, a protrusion 160 is formed on the large diameter surface of the valve body 118. When the valve body 118 moves, the protrusion 160 enters the recess 158 on the valve chamber 110 side, allowing the valve body 118 to move.

<Generation of Suction Force F by Valve Drive Mechanism 162>
10 shows the valve drive mechanism 162 of the proportional solenoid valve 78. The valve drive mechanism 162 drives the valve element 118 in the vertical direction when excited by a drive current id.
When a drive current id flows through the proportional solenoid 128, a magnetic field φ is generated in the proportional solenoid 128. This magnetizes the movable magnetic pole 126 and the yoke 132 (fixed magnetic pole), and different magnetic poles N and S are generated in the movable magnetic pole 126 and the yoke 132, and the movable magnetic pole 126 receives an attractive force F due to these magnetic poles N-S, and moves in the direction of the attractive force F. Regardless of the direction of the drive current id, different magnetic poles N and S are generated in the movable magnetic pole 126 and the yoke 132, and therefore an attractive force F due to the magnetic poles N-S acts.

<Polarity Reversal of Drive Current id>
When the polarity of the drive current id is reversed at regular intervals, the polarity of the magnetic poles N and S of the movable magnetic pole 126 and the yoke 132 is reversed, but an attractive force F acts between them in the same direction. As a result, a valve opening degree according to the current level of the drive current id can be obtained regardless of the polarity.
When the drive current id is reversed, the magnetization direction of the movable magnetic pole 126 and the yoke 132 is reversed, so that the residual magnetism is offset by the reversed current, and the influence of the residual magnetism can be eliminated.

<Control of proportional solenoid valve 78>
11 shows an example of control of the proportional solenoid valve 78. This control includes generation of the drive current id (S201), polarity inversion of the drive current id (S202), current level control of the drive current id (S203), and the like.
Generation of driving current id (S201): The control device 66 generates a driving current id to be flowed through the proportional solenoid 128.

Reversing polarity of drive current id (S202): The control device 66 reverses the polarity of the drive current id at a period faster than the movement speed of the valve disc 118. The movement of the valve disc 118 depends on fluctuations in the current level of the drive current id, and the polarity of the drive current id is reversed at a period faster than the movement speed of the valve disc 118, for example, at a period that is ½ the dither period Td.
Current level control of drive current id (S203): The control device 66 controls the current level of the drive current id, and controls the valve mechanism 114 to a valve opening degree according to the current level.

12 shows an example of polarity inversion and level control of the drive current id in this control process. This control process includes input of a control signal Sin (S301), calculation of a duty ratio of a forward pulse (S302), calculation of a duty ratio of a reverse pulse (S303), generation of a forward pulse (execution of pulse control according to the calculated duty ratio) (S304), generation of a reverse pulse (execution of pulse control according to the calculated duty ratio) (S305), control of the valve opening (S306), etc.
Input of control signal Sin (S301): The control device 66 receives a control signal Sin for controlling the valve opening degree of the valve mechanism 114. The valve opening degree is controlled by the signal level of this control signal Sin.

Calculation of Duty Ratio of Forward Pulse (S302): The control device 66 calculates the duty ratio of the forward pulse excluding the polarity control pulse Psw1 (polarity reversal portion) described later.
Calculation of Duty Ratio of Reverse Pulse (S303): The control device 66 calculates the duty ratio of the reverse pulse excluding the polarity control pulse Psw2 (polarity reversal portion) described later.

Generation of forward pulse (execution of pulse control with calculated duty ratio) (S304): The control device 66 generates a forward pulse for generating a forward drive current id to be passed through the proportional solenoid 128. This forward pulse includes a polarity control pulse Psw1 at the beginning as a polarity reversal section for reversing the current direction of the drive current id faster than the movement of the valve body 118. This polarity control pulse Psw1 has a larger pulse width than the other forward pulses, making it a high duty ratio pulse. The polarity reversal section in the forward pulse is used to switch the polarity of the reverse drive current id to the forward drive current id.

Generation of reverse pulse (execution of pulse control with calculated duty ratio) (S305): The control device 66 generates a reverse pulse for generating a reverse drive current id to be passed through the proportional solenoid 128. This reverse pulse includes a polarity control pulse Psw2 at the beginning as a polarity reversal portion for reversing the current direction of the drive current id faster than the movement of the valve body 118. This polarity control pulse Psw2 has a larger pulse width than the other reverse pulses, and is a high duty ratio pulse. The polarity reversal portion in the reverse pulse is used to switch the polarity of the forward drive current id to the reverse drive current id.
Control of valve opening degree (S306): The control device 66 controls the current level of the drive current id in accordance with the signal level of the control signal Sin, thereby controlling the valve opening degree.

<Polarity Reversal of Drive Current id, Its Level Control, and Attraction Force F>
13A shows a forward PWM pulse, which is an example of a forward pulse. This forward pulse is generated for a period of 1/2 the dither period Td (=Td/2), and includes a polarity control pulse Psw1 as a polarity reversal part at the beginning. The polarity control pulse Psw1 has a constant pulse width to shorten the polarity reversal period during which the reverse drive current id is switched to the forward current.
On the other hand, the duty ratio of the forward PWM pulses excluding the polarity control pulse Psw1 is controlled by the control signal Sin. For convenience of explanation, the duty ratio is set to a constant value in A of Fig. 13, but the duty ratio is controlled to a different value depending on the valve opening degree.

FIG. 13B shows a reverse PWM pulse, which is an example of a reverse pulse. This reverse pulse is generated for a period of 1/2 (=Td/2) of the dither period Td, and includes a polarity control pulse Psw2 as a polarity reversal part at the beginning. The polarity control pulse Psw2 has a constant pulse width in order to shorten the polarity reversal period in which the forward drive current id is switched to the reverse direction. In this embodiment, the polarity control pulses Psw1 and Psw2 have the same pulse width.
On the other hand, the duty ratio of the reverse PWM pulses excluding the polarity control pulse Psw2 is controlled by the control signal Sin. For convenience of explanation, the duty ratio is set to a constant value in B of Fig. 13, but the duty ratio is controlled to a different value depending on the valve opening degree.

13C shows the driving current id flowing in the forward or reverse direction. The driving current id is repeatedly switched from the reverse driving current id to the forward driving current id and further from the forward driving current id to the reverse driving current id by alternately generating a polarity control pulse Psw1 and a polarity control pulse Psw2 every half of the dither period Td.
The drive current id with this polarity reversal depends on the duty ratio of the forward PWM pulse or the reverse PWM pulse, and the current level is controlled.

D in FIG. 13 shows the attractive force F acting on the movable magnetic pole 126 and the yoke 132 (fixed magnetic pole). The proportional solenoid 128 is excited by a drive current id with polarity reversal and level control, magnetizing the movable magnetic pole 126 and the yoke 132. The magnetic poles are reversed to a different pair every half of the dither period Td, and the attractive force F generated between the movable magnetic pole 126 and the yoke 132 depends on the level of the drive current id.

Effects of the First Embodiment
According to the first embodiment, any one of the following effects can be obtained.
(1) The polarity of the drive current id is reversed at half the dither period Td (=Td/2) to reverse the magnetic pole between the movable magnetic pole 126 and the yoke 132 by the proportional solenoid 128, thereby canceling out residual magnetism. This polarity reversal is performed at a period faster than the opening and closing of the valve mechanism 114, so it does not affect the control of the valve opening degree.
(2) During the time interval of polarity reversal, the current level of the drive current id is controlled by the duty ratio of the forward PWM pulse or the reverse PWM pulse. Therefore, the valve opening of the valve mechanism 114 can be controlled by the current level of the drive current id without being affected by the polarity reversal of the drive current id.

Second Embodiment
Fig. 14 shows a control system 102 for the proportional solenoid valve 78 according to a second embodiment. In the configuration of Fig. 14, the same parts as those in Fig. 8 are given the same reference numerals.
The driving section 148 includes a power supply 164, a driving bridge circuit 166, a forward driving circuit 168-1, and a reverse driving circuit 168-2. The power supply 164 constitutes a current source of a driving current id.
The drive bridge circuit 166 includes Pch-FETs (P-channel field effect transistors) 171 and 172 and Nch-FETs (N-channel field effect transistors) 173 and 174 .

The forward drive circuit 168-1 receives a forward PWM pulse from the control unit 150 and passes a forward drive current id from the drive bridge circuit 166 to the proportional solenoid 128. In contrast, the reverse drive circuit 168-2 receives a reverse PWM pulse from the control unit 150 and passes a reverse drive current id from the drive bridge circuit 166 to the proportional solenoid 128. In other words, in a half cycle (= Td/2) of the dither cycle Td, the forward drive current id flows to the proportional solenoid 128 due to the conduction of the Pch-FET 172 and Nch-FET 173, and in the next half cycle (= Td/2) of the dither cycle Td, the reverse drive current id flows to the proportional solenoid 128 due to the conduction of the Pch-FET 171 and Nch-FET 174.

The control unit 150 includes a control circuit 176, a pulse generating unit 178, a PWM generating unit 180, and a logic circuit 182. The control circuit 176 is configured by a microcomputer, and includes a processor 184, a storage unit 186, and an input/output unit (I/O) 188. The processor 184 executes a control program stored in the storage unit 186, and executes control such as pulse width control in response to the control signal Sin.
Such control and control information includes:
a) Control information for generating the drive current id; b) Control information for reversing the polarity of the drive current id at a period faster than the movement of the valve body 118; c) Control information for controlling the valve opening degree by the current level of the drive current id; d) Calculation of the duty ratio of the forward pulse excluding the polarity control pulse; e) Calculation of the duty ratio of the reverse pulse excluding the polarity control pulse; f) Generation of a forward pulse including a control pulse for switching the polarity of the reverse drive current id to the forward direction (execution of the calculated pulse control).
g) Generation of a reverse pulse including a control pulse for switching the polarity of the forward drive current id to the reverse direction (execution of the calculated pulse control)
Includes:

The storage unit 186 is an example of a recording medium that stores the program of the present disclosure. The storage unit 186 uses memory elements such as a read-only memory (ROM), a random-access memory (RAM), and an electrically erasable programmable read-only memory (EEPROM), and is used to generate and store various types of control information.
The I/O 188 receives the control signal Sin and generates control information.
The pulse generating section 178 generates a clock pulse with a constant period, and generates a pulse with a constant period by dividing or doubling the frequency of this clock pulse.

The PWM generating unit 180 has a forward PWM pulse generating function and a reverse PWM pulse generating function, generates a forward PWM pulse or a reverse PWM pulse having a duty ratio according to the signal level of the control signal Sin, and outputs it to the logic circuit 182.
The logic circuit 182 receives a control pulse synchronized with a half period of the dither period Td from the pulse generating unit 178, and outputs a forward PWM pulse and a reverse PWM pulse synchronized with Td/2. The forward PWM pulse is provided to the forward drive circuit 168-1, and the reverse PWM pulse is provided to the reverse drive circuit 168-2.

<Advantages of the Second Embodiment>
According to the second embodiment, any one of the following effects can be obtained.
(1) The polarity of the drive current id is reversed at half the dither period Td (=Td/2) to reverse the magnetic pole between the movable magnetic pole 126 and the yoke 132 by the proportional solenoid 128, thereby canceling out residual magnetism and improving the hysteresis characteristics.
(2) During the time interval of polarity reversal, the current level of the drive current id can be controlled by the duty ratio of the forward PWM pulse or the reverse PWM pulse. This makes it possible to improve the controllability of the valve opening of the valve mechanism 114 by the current level of the drive current id without being affected by the polarity reversal of the drive current id.

(3) Since the influence of residual magnetism in the proportional solenoid valve 78 can be reduced or avoided, the difference in valve opening in response to the drive current id in the increasing and decreasing directions of the fuel gas G is small, and the difference between the increase and decrease of the fuel gas G can be prevented.
(4) Changes in the combustion state are suppressed, and the combustion state can be stabilized.
(5) The controllability of the hot water supply control is improved, and deviations in the temperature of the hot water at the outlet when the fuel gas G is increasing and decreasing can be prevented.
(6) In the production line, the secondary pressure of the gas after passing through the proportional solenoid valve can be easily set, and the production efficiency of the water heater 2 can be improved.

Third embodiment
Fig. 15 shows a valve unit 44 and a control system 200 according to a third embodiment. In the configuration of Fig. 15, the same parts as those in Figs. 8 and 14 are denoted by the same reference numerals.
In the second embodiment (FIG. 14), the control device 66 is provided with a drive unit 148 and a control unit 150. In contrast, in a control system 200 of the third embodiment, the drive unit 148 and the control unit 150 are installed together with the proportional solenoid valve 78 inside a valve unit housing 67. The control device 66 is provided outside this valve unit 44.

Control device 66 is, for example, configured as a computer, and includes a processor 202, a storage unit 204, and an I/O 206. Processor 202 executes a hot water supply control program and the like stored in storage unit 204. This information processing includes control of the hot water supply temperature and the like using detection information from water volume sensor 50, temperature sensors 48, 58, 64, and the like.
In this control device 66 , the processor 202 and the previously described processor 184 may be shared, the memory unit 204 and the previously described memory unit 186 may be shared, and the I/O 206 and the I/O 188 may be shared.

<Advantages of the Third Embodiment>
According to the third embodiment, any one of the following effects can be obtained.
(1) The same effects as those of the first and second embodiments can be obtained.
(2) The control function of the proportional solenoid valve 78 can be integrated into the valve unit 44, making the control device 66 more compact and facilitating maintenance.

[Experimental Results]
FIG. 16 shows the output characteristics of the proportional solenoid valve 78 driven by a drive current id without polarity switching, with the horizontal axis representing time and the vertical axis representing the secondary gas pressure of the proportional solenoid valve 78.
When the proportional solenoid 128 is excited by a drive current id without polarity reversal, the effect of residual magnetism cannot be eliminated because the drive current id is unidirectional. In other words, the magnetization is emphasized by the drive current id in the same direction as the residual magnetism, whereas the magnetization by the drive current id in the opposite direction to the residual magnetism is impaired due to the offset of the residual magnetism. As a result, the effect of the hysteresis h between the control signal Sin and the secondary gas pressure due to the valve opening becomes significant.

Similarly, FIG. 17 shows the output characteristics of the proportional solenoid valve 78 driven by a drive current id with polarity switching, with the horizontal axis representing time and the vertical axis representing the secondary gas pressure of the proportional solenoid valve 78.
When the proportional solenoid 128 is excited by a drive current id accompanied by polarity reversal, the residual magnetism is offset by the drive current id due to the polarity reversal, and a relationship between the drive current id and the secondary gas pressure due to the valve opening degree that is not affected by the residual magnetism is obtained. As a result, the effect of the hysteresis h between the control signal Sin and the valve opening degree is improved to a negligible level.

Other Embodiments
(1) In the above embodiment, PWM control is used as an example. However, the proportional solenoid valve 78 may be controlled by a method other than PWM control.
(2) The inversion period of the drive current id is set to half the dither period Td, but it need only be faster than the moving speed of the valve disc 118, and is not limited to the period in the embodiment.
(3) In the above embodiment, the polarity control pulse is illustrated as an example in the polarity reversal portion included in the forward pulse or reverse pulse, but this polarity control pulse may be a pulse generated by PWM control or a polarity reversal pulse generated separately from PWM control. This polarity reversal pulse may have a period including an optimal polarity reversal timing for reversing the polarity of the drive current id, and may have a pulse width set to an optimal time width.
(4) In the first embodiment, a hot water supply device is given as an example of a heat source device. However, instead of this hot water supply device, a reheating hot water supply device, a heating hot water supply device, or the like may be used.

As described above, the most preferred embodiment of the configuration of the present invention has been described. The present invention is not limited to the above description, and various modifications and changes can be made by those skilled in the art based on the gist of the invention described in the claims or disclosed in the description for carrying out the invention. It goes without saying that such modifications and changes are included in the scope of the present invention.

According to the present invention, the magnetic pole relationship between the movable magnetic pole and the fixed magnetic pole (yoke) can be reversed by the driving current, canceling out residual magnetism, and the valve mechanism can be driven by a magnetic force that is not affected by residual magnetism. This improves the hysteresis characteristics of the proportional solenoid valve, thereby improving the controllability of fuel control, hot water supply control, and other controllability in heat source devices that use proportional solenoid valves.

G Fuel gas 2 Water heater 4 Housing 6 Hot water supply port 8 Water supply port 10 Fuel gas port 12 Drain port 14 Exhaust port 16 Hot water supply pipe 18 Water supply pipe 20 Gas pipe 22 Combustion chamber 24 Burner 24-1, 24-2 Burner section 26 Igniter 27 Spark plug 28 Flame rod 30 Air intake fan 32 Primary heat exchanger 34 Secondary heat exchanger 35 Connecting pipe 36 Drain receiver 38 Drain tank 40 Drain discharge pipe 42 Gas supply pipe 42-1, 42-2 Gas supply pipe 44 Valve unit 46 Water supply pipe 48 Temperature sensor 50 Water volume sensor 52 Mixed water control valve 54 Hot water outlet pipe 56 Hot water supply pipe 58 Temperature sensor 60 Water control valve 62 Bypass pipe 64 Temperature sensor 66 Control device 67 Valve unit housing 68 Inlet port 70-1, 70-2 Outlet port 72 Solenoid valve 74, 76 Solenoid valve 78 Proportional solenoid valve 102, 200 Control system 108 Passage 110 Valve chamber 112-1 Inlet port 112-2 Outlet port 114 Valve mechanism 116 Valve seat 118 Valve body 120 Shaft portion 122 Support member 124 Diaphragm 126 Movable magnetic pole 128 Proportional solenoid 130 Coil 132 Yoke 134 Coil bobbin 136 Support frame 138 Space portion 140 Support member 142 Spring support portion 144 Spring insertion portion 146 Spring 148 Drive portion 150 Control portion 151 Holding frame 152 O-ring 154 Conical surface portion 156 Valve opening portion 158 Concave portion 160 Convex portion 162 Valve drive mechanism 164 Power source 166 Drive bridge circuit 168-1 Forward drive circuit 168-2 Reverse drive circuit 171, 172 Pch-FET
173, 174 Nch-FET
176 Control circuit 178 Pulse generating section 180 PWM generating section 182 Logic circuit 184, 202 Processor 186, 204 Memory section 188, 206 Input/output section (I/O)

Claims (8)

A burner for burning fuel gas;
a proportional solenoid valve disposed in a flow passage of the fuel gas to adjust the fuel gas to the burner;
a drive unit that generates a drive current and excites a proportional solenoid of the proportional solenoid valve with the drive current;
a control unit which magnetizes the yoke and the movable magnetic pole to different magnetic poles by excitation of the proportional solenoid regardless of the flow direction of the drive current, moves a valve body of the proportional solenoid valve by an attractive force between the movable magnetic pole and the yoke, and generates an alternating magnetic field by reversing the polarity of the drive current at a period faster than the movement of the valve body, thereby canceling out at least the residual magnetism of the movable magnetic pole;
The control unit includes:
a logic circuit that generates a forward pulse including a polarity reversal section that reverses the polarity of the driving current in the reverse direction to a forward direction, and generates a reverse pulse including a polarity reversal section that reverses the polarity of the driving current in the forward direction to a reverse direction;
a pulse width control section that controls a duty ratio of the forward pulse excluding a polarity reversal section, or a duty ratio of the reverse pulse excluding a polarity reversal section;
A heat source device comprising : a heat exchanger that exchanges heat of combustion of the fuel gas with a fluid to be heated;
A temperature sensor for detecting a temperature of the heated fluid;
2. The heat source device according to claim 1, wherein the control unit receives a detected temperature of the heated fluid, changes a current level of the drive current in response to the detected temperature, and controls a valve opening degree of the proportional solenoid valve. A control method using a proportional solenoid valve to control fuel gas, comprising:
generating a drive current for energizing a proportional solenoid of the proportional solenoid valve;
combusting the fuel gas that has passed through the proportional solenoid valve;
a step of magnetizing the yoke and the movable magnetic pole to different magnetic poles by excitation of the proportional solenoid regardless of the flow direction of the drive current, moving a valve body of the proportional solenoid valve by an attractive force between the movable magnetic pole and the yoke, and reversing the polarity of the drive current at a period faster than the movement of the valve body to generate an alternating magnetic field, thereby canceling out at least the residual magnetism of the movable magnetic pole;
generating a forward pulse including a polarity reversal portion that reverses the polarity of the driving current in a reverse direction to a forward direction;
generating a reverse pulse including a polarity reversal portion that reverses the polarity of the forward driving current to a reverse direction;
controlling a duty ratio of the forward pulse excluding a polarity reversal portion;
controlling a duty ratio of the reverse pulse excluding the polarity reversal portion;
A control method comprising: exchanging heat of combustion of the fuel gas with a heated fluid;
detecting a temperature of the heated fluid, and changing a current level of the drive current in response to the detected temperature of the heated fluid to control a valve opening degree of the proportional solenoid valve;
The control method according to claim 3 , comprising: A program implemented by a computer,
A function of generating control information for generating a drive current for exciting the proportional solenoid;
A function of igniting a burner and burning fuel gas that has passed through a proportional solenoid valve equipped with the proportional solenoid;
a function of magnetizing the yoke and the movable magnetic pole to different magnetic poles by excitation of the proportional solenoid regardless of the flow direction of the drive current, moving the valve element of the proportional solenoid valve by the magnetic attraction force generated between the movable magnetic pole and the yoke, and reversing the polarity of the drive current at a period faster than the movement of the valve element to generate an alternating magnetic field, thereby offsetting at least the residual magnetism of the movable magnetic pole;
A function of generating a forward pulse including a polarity reversal portion that reverses the polarity of the driving current in the reverse direction to a forward direction;
A function of generating a reverse direction pulse including a polarity reversal portion that reverses the polarity of the forward driving current to a reverse direction;
A function of controlling the duty ratio of the forward pulse excluding the polarity reversal portion;
A function of controlling the duty ratio of the reverse pulse excluding the polarity reversal portion;
A program for realizing the above by the computer. A recording medium storing the program according to claim 5 . a drive unit that generates a drive current for exciting a proportional solenoid that controls a valve opening degree by excitation, and passes the drive current through the proportional solenoid;
a control unit that ignites a burner, burns fuel gas that has passed through a proportional solenoid valve equipped with the proportional solenoid, magnetizes a yoke and a movable magnetic pole to different magnetic poles by exciting the proportional solenoid regardless of the flow direction of the drive current, moves a valve body of the proportional solenoid valve by an attractive force between the movable magnetic pole and the yoke, and reverses the polarity of the drive current at a period faster than the movement of the valve body to generate an alternating magnetic field, thereby offsetting at least the residual magnetism of the movable magnetic pole;
The control unit includes:
a logic circuit that generates a forward pulse including a polarity reversal section that reverses the polarity of the driving current in the reverse direction to a forward direction, and generates a reverse pulse including a polarity reversal section that reverses the polarity of the driving current in the forward direction to a reverse direction;
a pulse width control section that controls a duty ratio of the forward pulse excluding a polarity reversal section, or a duty ratio of the reverse pulse excluding a polarity reversal section;
A control device comprising : A hot water supply device comprising a heat source device as described in claim 1 or claim 2 , a control method as described in claim 3 or claim 4 , a program as described in claim 5 , a recording medium as described in claim 6 , or a control device as described in claim 7 , for heating water and supplying hot water at a hot water supply temperature heated to a set temperature.

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