JPH05203144A - Ignition heater temperature controller - Google Patents

Abstract

PURPOSE:To obtain a temperature controller of a ceramic ignition heater, by which the temperature rise is stimulated to shorten the ignition period of time without a reduction in the specified life time of the ignition heater. CONSTITUTION:A heater energizing device 1 applies a high voltage exceeding the temperature endurance limit on an ignition heater 3. When a resistance detection judgement device 8 detects an energizing-stop resistance value within the temperature endurance limit from the ignition heater 3 and transmits a signal to a heater energizing controller 9, the controller 9 instructs a switch element 4 to stop power supply to the ignition heater 3. On the other hand, a timer 10 begins to count time on receipt of the signal, and when it counts a period of time required for the temperature of a ceramic 7 of the ignition heater 3 to drop to the ignition action allowable temperature, the ignition heater 3 is energized again via the heater energizing controller 9. Thus, the ignition heater 3 is controlled to the temperature of the temperature endurance limit to stimulate the temperature rise of the ceramic 7 without a reduction in the life.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature control device for an ignition heater mounted on a combustion instrument and having a heating element coated with ceramic.

[0002]

2. Description of the Related Art Conventionally, a ceramic ignition heater applied to a burning appliance is a ceramic ignition heater, which is a means for obtaining a stable predetermined heating temperature suitable for ignition in consideration of durability against heating temperature of a heating element such as a nichrome wire. A saturation temperature region (self-temperature control region) where the amount of heat radiated on the surface and the amount of heating of the internal resistance are saturated was used. Then, the heating element energizes the ceramic ignition heater with a predetermined voltage equal to or lower than the temperature endurance limit, and the heating temperature and the internal resistance of the heating element first change proportionally with positive characteristics to raise the heating temperature, and after a while. The temperature reaches the saturation temperature range of the temperature endurance limit and self-temperature control is performed to provide a stable predetermined heating temperature suitable for ignition.

As another control method, the heating temperature of the heating element and the thermal saturation region of the internal resistance are set above the temperature endurance limit of the heating element, and a high voltage corresponding to this high heating temperature is applied. The heating element temperature rises rapidly, the energization is stopped just before the temperature durability limit of the heating element, and thereafter the ignition operation can be repeated by turning on and off the energization to the ceramic ignition heater in a cycle with an appropriate energization stop time. In this state, the startup time required for ignition preparation was shortened.

[0004]

However, in the above-mentioned conventional ceramic ignition heater, the above-mentioned conventional control system applies a low voltage at which the heating element is automatically saturated at the temperature endurance limit to reach the temperature saturation region. There was a problem that the startup time was long (several tens of seconds) and the ignition timing was delayed.

Further, in the control method described later, when a high voltage applied to the ceramic ignition heater is voltage-adjusted and supplied by a transformer and the external input voltage to the transformer is not changed, the external input voltage is reduced. In conjunction with this, the applied voltage to the heating element automatically decreases, and the predetermined heating temperature cannot be obtained, and the heating temperature decreases. On the contrary, when the external input voltage is high, the heating temperature rises above the predetermined temperature as the applied voltage rises.
The heating element has drawbacks such as shortening the life beyond the temperature endurance limit for maintaining a predetermined life.

In view of the above problems, the present invention realizes that the heating temperature of the ignition heater is rapidly raised and stably controlled to a predetermined heating temperature, and that the ignition heater needs to be started while maintaining a predetermined life. The purpose is to shorten the ignition time by accelerating the time.

[0007]

In order to achieve the above object, a first means of an ignition heater temperature control device of the present invention is an ignition heater in which a heating element whose internal resistance is energized to generate heat is coated with ceramics, and the heating element. Heater energizing means for applying a voltage exceeding the temperature endurance limit, a switch element for energizing the heater energizing means, and an energization stop resistance value equal to or less than the temperature endurance limit of the internal resistance at which the ignition heater can perform an ignition operation. A heater internal resistance determining means and a timer means for measuring a predetermined elapsed time from the time when the detection signal of the heater internal resistance determining means is received, and a detection signal of the heater internal resistance determining means to control the switch element to OFF. The heater energization control means for receiving a predetermined elapsed time measurement signal from the timer means and controlling ON of the switch element is provided.

The second means of the present invention is an ignition heater having a ceramic coating of a heating element whose internal resistance is energized to generate heat, a heater energizing means for applying a voltage exceeding the temperature endurance limit of the heating element, and a heater energizing means. And a heater for detecting an energization stop resistance value equal to or less than the temperature endurance limit and an energization start resistance value set below the energization stop resistance value of the internal resistance of the ignition heater capable of performing an ignition operation. The switch element is turned on / off by receiving a detection signal from the internal resistance determination means and the heater internal resistance determination means.
The heater energization control means for F control is provided.

[0009]

In the ignition heater temperature control device of the present invention by the first means, the heater energizing means which receives power from the external input power supply the ignition heater with a high voltage exceeding the temperature endurance limit for maintaining the predetermined life of the heating element. By applying, the heating element of the ignition heater is rapidly heated by the high current, and the heat is transferred to the ceramic covering the heating element to rapidly raise the temperature. Then, when the temperature endurance limit of the heating element is reached within a short time, the heater internal resistance determination means detects the energization stop resistance value corresponding to a preset predetermined heating temperature (within the temperature endurance limit). Upon receiving the detection signal, the heater energization control means instructs the switch element to stop energizing the ignition heater.

On the other hand, the detection signal of the heater internal resistance determination means is also input to the timer means, and the timer means starts time measurement from the time when the detection signal is received. Then, when it is predicted that the ceramic coating temperature of the ignition heater will fall to a predetermined heating temperature at which ignition operation is possible, and when the preset predetermined elapsed time has been measured, a measurement completion signal is input to the heater energization control means. Therefore, the heater energization control means instructs the switch element again to energize the ignition heater, the ignition heater is rapidly heated again, and the predetermined heating temperature corresponding to the energization stop resistance value is recovered in a short time.

In this way, the heater energization control means controls the switch element in accordance with the detection signals of the heater internal resistance judgment means and the timer means, and the high-voltage energization from the heater energization means to the ignition heater is effectively adjusted, whereby ignition is performed. The heater is controlled to a predetermined heating temperature near the temperature endurance limit to maintain a predetermined life, and the temperature of the ceramic is rapidly raised to accelerate the start-up time, and the ignition temperature is maintained in the heating temperature range for ignition. The time required can be shortened.

According to the second aspect of the present invention, according to the present invention, after the heater internal resistance determining means detects the energization stop resistance value and the energization to the ignition heater is stopped, the temperature of the ceramic coated on the surface of the ignition heater is reduced. When the temperature drops to a temperature at which the ignition can be performed, a preset energization start resistance value corresponding to this lowered temperature is detected. Upon receiving this detection signal, the heater energization control means instructs the switch element to stop energizing the ignition heater.

Thus, even if the degree of heat absorption by the outside air of the ceramic coating changes, the heater internal resistance determining means directly detects the upper and lower temperatures set so that the ignition heater can perform the ignition operation as resistance values. In comparison with a system in which a timer means for fixedly setting and measuring a uniform cooling time controls energization ON, the energization start temperature can be constantly controlled to a predetermined heating temperature and stable ignition required energy can be supplied. While maintaining a predetermined heating temperature near the temperature endurance limit and maintaining a predetermined life, the temperature of the ceramic is rapidly raised to speed up the start-up time, and the heating temperature range where ignition can be performed is maintained to maintain the required ignition time. Can be shortened.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of an ignition heater temperature control device of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. A heater energizing means 1 for receiving commercial AC power from the outside is connected to an ignition circuit 2 to supply a predetermined voltage to an ignition heater 3. The ignition circuit 2 also includes a switch element 4 that controls the energization of the ignition heater 3. The ignition heater 3 is a resistor 5 such as a nichrome wire.
And has a so-called positive characteristic that the resistance value increases in proportion to a predetermined temperature coefficient as shown in FIG. 2 when the internal resistance of the resistor 5 generates heat due to energization and rises in temperature. The electrically insulated heating element 6 is hardened and covered with a ceramic 7. The ignition circuit 2 is further connected with a resistance detection judging device 8 as a heater internal resistance judging means.

As is well known, the temperature of the resistor 5 such as the nichrome wire rises when a heat generating action is generated by energization. This heat is transmitted to the ceramic 7 and the ceramic 7 accumulates heat, and at the same time, a heat radiating action occurs to the outside air. Then, when the amount of heat released by this heat release function and the amount of heat generated by the heating element 6 whose internal resistance value has increased due to the temperature rise are balanced, the ignition heater 3 enters the temperature saturation state and the ceramic 7
Maintains a stable surface temperature. This temperature saturation state changes depending on the supply voltage of the heater energizing means 1 applied to the heating element 6, and if the supply voltage is high, the surface temperature of the ceramic 7 also increases in conjunction with it.

The curve S in FIG. 3 shows that the temperature saturation state is time t _s.
It shows that the internal resistance of the resistor 5 is stabilized at a constant value r _s .

When the heat generation temperature of the resistor 5 such as a nichrome wire rises, the material is consumed by so-called high temperature oxidation due to a chemical reaction with oxygen at a high temperature. Further, in relation to ignition characteristics, the temperature endurance limit for maintaining an appropriate life is unique to the material. Therefore, the resistance detected determiner 8 maintains the heating element 6 to a reasonable predetermined lifetime, the energization stopping resistance becomes temperature T _a close to the temperature endurance limit r _a (shown in FIG. 2), the de-energization resistance value Even if the resistance value of the resistor 5 decreases from r _{a, the} ignition operation can still be reliably expected, and the energization start resistance value r _{b at} which the temperature becomes T _b is set. The detection signals of the two resistance values r _a and r _b are output to the heater energization control means 9 and the timer means 10.

The heater energization control means 9 is a resistance detection judging device 8
When receiving the detection signal of, the switch element 4 is instructed to control the energization of the heater circuit 2. The timer means 10 receives a detection signal for starting energization and a detection signal for stopping energization of the ignition heater 3 from the resistance detection / determination unit 8, and measures a predetermined time respectively. When the resistance detection determiner 8 does not normally output the detection signal, when the measurement of the predetermined time is completed, the ON / OFF determination signal of the energization to the ignition heater 3 is output, and the ignition heater 3 is ignited. The operation is controlled instead of the resistance detection judging device 8. The predetermined time is distinguished time _{t 1, t 2, t 3} , a low outside air temperature, and to set the condition when the high pressure of the commercial AC power supply, compared determines that the detection value according to the current state.

With the above configuration, the switch element 4 is turned on.
Then, if the heater energizing means 1 is left energized, the curve S
The temperature becomes saturated and the internal resistance of the resistor 5 becomes r_sTona
Internal resistance r_aTemperature limit of the heating element 6
Exceeded temperature T_sSupply high voltage to the heater circuit 2
It Then, the resistance detection determiner 8 determines that the energization stop resistance value r_aTo
Upon detection, the energization control means 9 prevents overheating of the ignition heater 3.
Instruct switch element 4 to stop, and turn on ignition heater 3.
Turn off the power. From this energization start to energization stop
Time t₁Is the temperature T_aConventional car that is saturated with temperature
Time t _xCompared with the startup time of tens of seconds
Can be shortened.

In the ignition heater 3 which is deenergized, the ceramic 7 continuously radiates heat from the surface, and since there is no heat transfer supplement from the heating element 6, the amount of accumulated heat is gradually reduced and the temperature is lowered. When the drops to a temperature T _b ignitable region, the resistance detector decision unit 8 detects the energization start resistance r _b. With this detection signal, the heater energization control means 9 causes the switch element 4 to operate again.
Instructs the ignition heater 3 is energized ON the predetermined high voltage, to restore the ignition heater 3 which is temperature decrease rapidly degree to a temperature T _a. During the energization ON / OFF operation, the temperature of the ignition heater 3 is accurately maintained between T _a and T _b, and the required ignition energy capable of reliably performing the ignition operation can be radiated and supplied regardless of the time when the object to be ignited is supplied. ..

The commercial AC power source received by the heater energizing means 1 usually has a permissible range to supply power, and when the power supply of the permissible lower limit value is input, the supply voltage of the predetermined high voltage drops. Further, the ignition heater 3 has a temperature saturated state S at a predetermined high pressure S
It has a range of change from L to SH. However, in the state where the standard value S is set higher than the curve F and the lower limit value SL, the initial rising time moves from m1 to the m2 point, but still has a significant difference from the curve F and is not shown. However, the influence on the temperature recovery time in the repeated cycle can be suppressed to be small. Even if there is a slight delay in the required ignition time, it is possible to achieve a reliable ignition operation and shorten the start-up time compared to the conventional case.

Thus, the heater energizing means 1 supplies a high voltage such that the internal resistance of the resistor 5 at the time of temperature saturation exceeds the temperature endurance limit and still exceeds the lower limit value of the commercial power supply, and the rising time of the ignition heater 3 is increased. Even if the value is significantly shortened, the resistance detection determiner 8 accurately maintains the surface temperature of the ceramic 7 in an ignitable range close to the temperature endurance limit, and shortens the ignition time while ensuring the predetermined life of the heating element 6. Can be realized.

Further, the timer means 10 outputs a time measurement signal in place of the resistance detection judgment device 8 when the resistance detection judgment device 8 temporarily loses the detection signal due to disturbance noise or the like, and the heater energization control means. The switch element 4 is turned off by 9 and the runaway of the ignition heater 3 is stopped to avoid damage.

Further, when the resistance detection judging device 8 completely stops functioning and the detection signal cannot be outputted, the ignition heater 3 is provisionally provided.
Energization control. At this time, under a use environment condition apart from the time setting condition, a time zone occurs in which the surface temperature of the ceramic 7 falls below the temperature T _L of the ignitable region, and the ignition required time may be slightly delayed. Judgment device 8
Instead of the above, the ignition heater 3 can be protected from damage while controlling energization.

Next, although not shown, another embodiment of the present invention will be described. Heating element of the ignition heater ignition control at the time shortened upper deenergized resistance of close only temperature endurance limit possible for reduction r _a, and the energization start resistance r _b of the lower limit can only said energization stop resistance Controls close to the value r _a are desirable. However, both resistance values r _a in this narrow range,
The detection of r _b is naturally limited because of the resistance detection error. The de-energization resistance value r _a detected resistance detection determining unit 8 in this embodiment, the temperature of the ceramic in place of the detection of the conduction start resistance r _b corresponding to the resistance value r _b T _b temperature T
_The time when a falls is set by experimental data. Then, even when the use environment conditions away from the setting condition, if detecting the lower limit temperature T _b of equivalent to the previous example, average early to detect the lower limit temperature T _b by, maintained ceramic lower surface temperature to a higher temperature By doing so, a larger amount of required ignition energy can be radiated and supplied while maintaining the predetermined life of the ignition heater by the resistance detection determiner, and the required ignition time as a whole can be shortened.

It should be noted that the present invention is also applicable to a system in which the fuel of a combustion appliance such as a water heater or a heater is used as an ignited body to perform an ignition operation, and high-voltage energization to an ignition heater is controlled to a predetermined value with respect to a commercial input power source. The same effect can be exerted on the improvement of ignition performance such as the required time for raising.

[0028]

As described above, according to claim 1 of the ignition heater temperature control device of the present invention, when the heater energizing means continues energizing, a high voltage exceeding the temperature endurance limit of the heating element is applied to the ignition heater. By rapidly heating from the non-heated state, the heating time required for starting the ignition heater is shortened. Then, the heater internal resistance determination means detects an energization stop resistance value equal to or less than the temperature endurance limit from the internal resistance of the heating element, and the heater energization control means stops energization to the ignition heater by the switch element, and this energization stop When the timer means detects a predetermined elapsed time during which the ignition heater can be ignited from time to time, re-energization of the ignition heater is started and the ignition heater is maintained in a heating temperature range in which the ignition heater can be operated. The required ignition time can be shortened while maintaining a predetermined life.

According to a second aspect of the present invention, when the heater energizing means continues energizing, a high voltage exceeding the temperature endurance limit of the heating element is applied to the ignition heater to rapidly heat it from the non-heated state. Increase the heating time required for startup. Then, the heater internal resistance determination means detects the energization stop resistance value equal to or less than the temperature endurance limit and the energization start resistance value set to be equal to or less than the energization stop resistance value, and the heater energization control receiving the two detection signals. By maintaining the ignition heater in the heating temperature range in which the ignition operation is possible, the means can shorten the required ignition time while maintaining the predetermined life of the ignition heater.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of an ignition heater temperature control device of the present invention.

FIG. 2 is a characteristic diagram of the ignition heater.

FIG. 3 is a characteristic diagram of the ignition heater.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 heater energizing means 3 ignition heater 4 switch element 6 heating element 8 resistance detection judging device (heater internal resistance judging means) 9 heater energizing control means 10 timer means

Front page continued (72) Inventor Itsuo Igarashi 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Yoshimitsu Fujiwara, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] 1. An ignition heater in which a heating element whose internal resistance is energized to generate heat is coated with ceramic, a heater energizing means for applying a voltage exceeding a temperature endurance limit of the heating element, and a switch element for energizing and controlling the heater energizing means. Ignition heater is capable of igniting, and measures the internal resistance judgment means for detecting the energization stop resistance value equal to or less than the temperature endurance limit of the internal resistance and the predetermined elapsed time from the time when the detection signal of the heater internal resistance judgment means is received. The switch element is turned off by receiving the detection signal from the timer means that activates and the heater internal resistance determination means.
An ignition heater temperature control device having heater energization control means for controlling and turning on a switch element by receiving a predetermined elapsed time measurement signal of a timer means. 2. An ignition heater in which a heating element whose internal resistance is energized to generate heat is coated with ceramic, a heater energizing means for applying a voltage exceeding a temperature endurance limit of the heating element, and a switch element for energizing and controlling the heater energizing means. A heater internal resistance determination means for detecting an energization stop resistance value equal to or less than the temperature endurance limit and an energization start resistance value set to be less than or equal to the energization stop resistance value of the internal resistance with which the ignition heater can perform an ignition operation; An ignition heater temperature control device comprising heater energization control means for receiving a detection signal from a resistance determination means and controlling ON / OFF of a switch element.