JP7641850B2 - grill - Google Patents

Description

The present invention relates to a grill. In particular, the present invention relates to a grill having an afterburner in the exhaust passage.

Conventionally, as a grill incorporated in a cooking device, one in which an afterburner is provided in an exhaust passage communicating with the grill chamber is known (for example, Patent Document 1). Also known is a grill in which an air intake is opened in the side wall of the grill chamber (for example, Patent Document 2). With this grill, when the burner mounted on the grill is burned, the inside of the grill chamber becomes negative pressure due to the draft effect caused by the exhaust of the combustion exhaust gas, and air is taken into the grill chamber from the air intake. Therefore, in a grill with a lower burner, the combustion exhaust gas ejected from the lower burner can be blown far into the grill chamber by secondary air. Also, in a grill with an afterburner that increases the draft effect in the exhaust passage, the oil smoke and odorous components contained in the combustion exhaust gas flowing from the inside of the grill chamber into the exhaust passage are burned by the afterburner, and the combustion exhaust gas can be smoothly discharged to the outside from the exhaust port of the exhaust passage.

In the grill described above, a thermocouple is placed near the burner to detect the burner flame, and ignition failure or mid-fire is determined based on the output value of the electromotive force output from the thermocouple (for example, Patent Document 3).

However, in grills with air intakes on the side walls of the grill chamber, when the indoor temperature is low in winter and the draft effect is difficult to achieve, the combustion exhaust gas leaks from the air intake into the cooking device body. In general, the venturi part of the afterburner extends outward from the grill, so when the combustion exhaust gas leaks into the cooking device body from the air intake opening on the side wall, the combustion exhaust gas is likely to be taken in through the opening of the venturi part of the afterburner. When the combustion exhaust gas is taken in by the afterburner in this way, the proportion of primary air taken in by the afterburner decreases, resulting in a shortage of oxygen. As a result, the flame lift occurs, or part of the flame is blown away, causing a decrease in the output of the thermocouple that detects the flame, making it easy for ignition failure or misfire to occur. In particular, when a large cooking container such as a cocotte or a Dutch oven is stored in the grill chamber and cooked, the cooking container is placed near the air intake, and the flow path of the combustion exhaust gas from the air intake to the exhaust passage is blocked by the cooking container. This causes an increase in combustion exhaust gas leaking from the air intake, making the above problem more pronounced.

JP 2008-301979 A JP 2015-200471 A JP 2017-78558 A

The present invention solves the above problems, and its purpose is to prevent the afterburner from failing to ignite or going out mid-fire in a grill that has an afterburner in the exhaust passage and a grill chamber with an air intake opening in the side wall that supplies secondary air to the underburner, and to ensure stable afterburner combustion.

According to one aspect of the present invention,
A grill chamber accommodated in the cooking device body;
A lower fire burner provided in the grill chamber;
An exhaust passage for discharging combustion exhaust gas from inside the grill chamber to the outside;
an afterburner provided in the exhaust passage;
an afterburner thermocouple for detecting an afterburner flame;
A control unit that controls the combustion of the underburner and the afterburner,
A grill having an air intake opening on a side wall of the grill chamber for supplying secondary air to a lower burner,
A grill is provided in which the control unit initiates an ignition process for the afterburner at the start of cooking, and then ignites the underburner.

According to the above grill, the afterburner is ignited before the lower burner when cooking begins, which makes it easier for the draft effect to occur, whereby the exhaust gas is exhausted to the outside through the exhaust passage. Therefore, by igniting the lower burner after igniting the afterburner, it is possible to prevent the leakage of exhaust gas from the air intake into the cooking device body when the lower burner is ignited. This reduces the amount of exhaust gas taken in from the opening of the venturi part of the afterburner at the beginning of ignition, preventing the afterburner from igniting poorly and allowing the afterburner to burn stably, allowing cooking to start smoothly.

Preferably, in the grill,
The control unit ignites the lower burner when at least one of the following lower ignition conditions is satisfied: a first lower ignition condition in which an afterburner ignition process is started at the start of cooking and a predetermined time-lag ignition threshold time elapses after the output value of the afterburner thermocouple becomes equal to or greater than a predetermined ignition detection threshold, or a second lower ignition condition in which the afterburner ignition process is started at the start of cooking and the temperature inside the grill chamber becomes equal to or greater than a predetermined time-lag ignition threshold temperature after the output value of the afterburner thermocouple becomes equal to or greater than a predetermined ignition detection threshold.

With the above grill, the lower burner is ignited after the afterburner has sufficiently generated a draft effect, which further reduces the leakage of combustion exhaust gas from the air intake into the cooking device body. This reliably prevents the afterburner from failing to ignite.

According to another aspect of the present invention,
A grill chamber accommodated in the cooking device body;
A lower fire burner provided in the grill chamber;
An exhaust passage for discharging combustion exhaust gas from inside the grill chamber to the outside;
an afterburner provided in the exhaust passage;
an afterburner thermocouple for detecting an afterburner flame;
A control unit that controls the combustion of the underburner and the afterburner,
A grill having an air intake opening on a side wall of the grill chamber for supplying secondary air to a lower burner,
The control unit starts the ignition process of the lower burner and the afterburner at the start of cooking, and then reduces the heat of the lower burner if the output value of the afterburner thermocouple does not become equal to or greater than a predetermined ignition detection threshold within a predetermined first ignition judgment time.
A grill is provided in which, after reducing the heat of the lower burner, if the output value of the afterburner thermocouple becomes equal to or greater than the ignition detection threshold within a second predetermined ignition determination time, the heat of the lower burner is increased.

According to the above grill, the lower burner and the afterburner are ignited at the start of cooking, so that the discomfort of the user performing the ignition operation can be reduced. On the other hand, if the lower burner and the afterburner are ignited at the start of cooking, when the draft effect is difficult to apply, the amount of combustion exhaust gas leaking from the air intake into the cooking device body increases, and the afterburner is likely to fail to ignite. However, according to the above grill, if the output value of the afterburner thermocouple does not reach or exceed the ignition detection threshold within the first ignition judgment time after the afterburner is ignited, the firepower of the lower burner is reduced, so that the leakage of combustion exhaust gas from the air intake into the cooking device body can be reduced. And according to the above grill, if the output value of the afterburner thermocouple reaches or exceeds the ignition detection threshold within the second ignition judgment time after reducing the firepower of the lower burner, the firepower of the lower burner is increased, so that the afterburner can be ignited stably, and cooking can be started smoothly.

According to yet another aspect of the present invention,
A grill chamber accommodated in the cooking device body;
A lower fire burner provided in the grill chamber;
An exhaust passage for discharging combustion exhaust gas from inside the grill chamber to the outside;
an afterburner provided in the exhaust passage;
an afterburner thermocouple for detecting an afterburner flame;
A control unit that controls the combustion of the underburner and the afterburner,
A grill having an air intake opening on a side wall of the grill chamber for supplying secondary air to a lower burner,
The control unit determines that the afterburner has misfired during cooking while the underburner and the afterburner are burning, when a misfire determination condition is met in which a state in which an output value of the afterburner thermocouple falls below a predetermined misfire determination threshold continues for a predetermined misfire determination time or longer,
During cooking with the lower burner and the afterburner burning, when the output value of the afterburner thermocouple is higher than the misfire judgment threshold in the misfire judgment condition but falls to a predetermined oxygen deficiency judgment threshold, the heat of the lower burner is reduced,
A grill is provided in which, after reducing the heat of the lower burner, when the output value of the afterburner thermocouple returns to above the oxygen deficiency determination threshold, the heat of the lower burner is increased.

When cooking with the underburner and afterburner burning, if the internal pressure inside the grill chamber increases, exhaust gas from the air intake may leak into the cooking appliance body, causing the afterburner flame to lift or some of the flame to blow away, resulting in a decrease in the output value detected by the afterburner thermocouple.

However, with the above grill, during cooking with the underburner and afterburner burning, the output value of the afterburner thermocouple is higher than the misfire judgment threshold in the misfire judgment conditions, but when it falls to the oxygen deficiency judgment threshold, the heat of the underburner is reduced, so that the leakage of combustion exhaust gas from the air intake into the cooking appliance body can be reduced. And with the above grill, when the output value of the afterburner thermocouple returns to above the oxygen deficiency judgment threshold after the heat of the underburner is reduced, the heat of the underburner is increased, so that misfire in the afterburner can be prevented and the afterburner can be burned stably, allowing cooking to continue smoothly.

Preferably, in the grill,
If the output value of the afterburner thermocouple does not return to the oxygen deficiency determination threshold or higher even when the heat power of the lower burner is reduced, the control unit relaxes the afterburner misfire determination condition.

When the afterburner burns due to lack of oxygen, the output value of the afterburner thermocouple decreases because a flame lift or a part of the flame is blown away, but a certain flame may be formed in areas other than the flame hole detected by the afterburner thermocouple. On the other hand, with the above grill, when the output value of the afterburner thermocouple falls to the oxygen deficiency judgment threshold, the firepower of the lower burner is reduced, so that even if the output value of the afterburner thermocouple drops significantly temporarily, the leakage of combustion exhaust gas from the air intake into the cooking device body is reduced, improving the oxygen deficiency combustion of the afterburner and allowing the afterburner to return to normal combustion. Therefore, by slowing down the afterburner misfire judgment conditions, it is possible to prevent the afterburner from misfiring midway, and the afterburner can burn stably, allowing cooking to continue smoothly.

Preferably, the grill comprises:
It has a container cooking mode in which a cooking container is placed inside the grill chamber and cooked.

The above grill can reliably prevent the afterburner from failing to ignite or from catching fire midway, even when cooking in container cooking mode, which increases the amount of exhaust gas leaking from the air intake into the cooking appliance body.

As described above, according to the present invention, in a grill equipped with an afterburner in the exhaust passage and a grill chamber with an air intake opening in the side wall for supplying secondary air to the underfire burner, it is possible to prevent the afterburner from failing to ignite or going out midway, and to ensure stable afterburner combustion.

FIG. 1 is a schematic perspective view showing a cooking device according to a first embodiment of the present invention. FIG. 2 is a schematic vertical cross-sectional view showing the cooking device according to the first embodiment of the present invention. FIG. 3 is a schematic cross-sectional view showing the cooking device according to the first embodiment of the present invention. FIG. 4 is a block diagram showing the cooking device according to the first embodiment of the present invention. FIG. 5 is a flowchart showing an example of a control operation of the cooking device according to the first embodiment of the present invention. FIG. 6 is a flowchart showing an example of a control operation of the cooking device according to the second embodiment of the present invention. FIG. 7 is a flowchart showing an example of a control operation of the cooking device according to the third embodiment of the present invention.

(Embodiment 1)
Hereinafter, a cooking device equipped with a grill according to the present embodiment will be specifically described with reference to the drawings.
FIG. 1 is a schematic perspective view showing an example of a cooking device according to the present embodiment, which is applied to a built-in gas stove. The gas stove 1 includes a plurality of stove burners 5 facing upward from a stove opening (not shown) in a top plate 11, and a grill 2 built into a stove body 10, which is a cooking device body. The grill 2 includes a grill chamber 20 in the shape of a substantially rectangular box housed in the stove body 10, and a grill door 21 that covers a front opening 200 of the grill chamber 20 from the front. Cooking utensils such as a grill net (not shown) and a cooking vessel 4 made of metal or ceramic, such as a cocotte or a Dutch oven, are stored in the grill chamber 20. In this specification, the grill door 21 side is the front side, and when the gas stove 1 is viewed from the grill door 21 side, the direction in which the grill door 21 faces the back side of the grill chamber 20 is called the front-rear direction, the width direction of the grill chamber 20 is called the left-right direction, and the height direction of the grill chamber 20 is called the up-down direction.

A guide frame 211 is provided at each of the left and right sides of the lower rear surface of the grill door 21, extending toward the rear of the stove body 10. Each guide frame 211 is supported in a state in which it can slide back and forth within the stove body 10, and the grill door 21 is connected and fixed to both front ends of the guide frames 211. Therefore, the grill door 21 slides back and forth relative to the front surface 13 of the stove body 10 to open and close.

As shown in Figures 2 and 3, a narrow connecting plate 212 that protrudes toward the inside of the grill chamber 20 is provided on the lower rear surface of the grill door 21, and a receiving frame 15 for supporting the drip tray 12, a grill net (not shown), a container support 44, etc. is connected to and supported on the upper part of the connecting plate 212.

The receiving frame 15 has a front end connected to the connecting plate 212, and a rear end supported in a slidable state on the upper surface of the bottom wall 204 of the grill chamber 20. Therefore, the receiving frame 15 is pulled out from inside the grill chamber 20 toward the front of the front opening 200 in conjunction with the grill door 21 being opened, and is stored inside the grill chamber 20 in conjunction with the grill door 21 being closed.

The cooking container 4 has, for example, a flat-bottomed container body 40 that is generally rectangular in plan view and opens upward, and a lid body 41 that is generally rectangular in plan view and covers the upper opening of the container body 40 from above. When using the cooking container 4, it is stored in the container support 44 in a vertical position with the longitudinal direction of the container body 40 facing the side wall 203 of the grill chamber 20.

The container support 44 consists of a frame made of multiple metal round bars joined together. The container support 44 is constructed so that it can support the cooking container 4 horizontally at a predetermined position by deforming multiple wires into a predetermined shape to match the shape of the side and bottom of the cooking container 4 and joining them at predetermined positions. Specifically, the container support 44 has left and right lower support frames that extend in the front-to-rear direction and abut against the bottom surface of the container body 40 to support the container body 40 from below, and an upper frame body that is roughly rectangular and annular in plan view and is joined to the upper ends of the left and right lower support frames.

An exhaust duct 30 that constitutes an exhaust passage 300 that discharges combustion exhaust gas from the grill chamber 20 to the outside is connected to the rear wall 205 of the grill chamber 20. The exhaust duct 30 extends obliquely upward from the upper part of the rear wall 205 of the grill chamber 20 toward the underside of the top plate 11, and the exhaust port 301 at its upper end faces the grill opening 14 opened on the top surface of the top plate 11 from below.

The grill 2 is equipped with an upper burner 22 arranged along the top wall 202 of the grill chamber 20, left and right lower burners 23 arranged along the left and right side walls 203 of the grill chamber 20, and an afterburner 7 arranged on the bottom wall 31 of the exhaust duct 30 near the rear wall 205 of the grill chamber 20. The left and right lower burners 23 have the same configuration except that they are symmetrical, so the configuration of the lower burner 23 and its surroundings will be mainly described using the right lower burner 23 as an example.

The upper burner 22 is a surface combustion type ceramic burner whose underside is made of a ceramic combustion plate, and a large number of flame holes 220 are opened over almost the entire underside of the plate. Therefore, when the upper burner 22 is ignited, a flame is formed over the entire underside of the plate, and combustion exhaust gas and radiant heat are released downward inside the grill chamber 20, heating the cooking vessel 4 from above. The upper burner 22 has a venturi section 221 extending outward to the right from the upper wall 202 of the grill chamber 20 at its rear. Although not shown, a gas nozzle is inserted into the opening that opens at the outer end of the venturi section 221. Therefore, when fuel gas is ejected from the gas nozzle toward the opening of the venturi section 221, the fuel gas is sucked into the venturi section 221 together with the air around the opening, and a mixture of fuel gas and primary air is generated and supplied to the flame hole 220.

The lower burner 23 is a straight tube made of two stainless steel trough-shaped bodies stacked one on top of the other, and multiple flame holes 230 are formed on the side end surface of the tube on the inner side of the grill chamber 20. The flame holes 230 open horizontally toward the inside of the grill chamber 20. The lower burner 23 is also arranged so that the flame holes 230 face the side of the container body 40 of the cooking container 4 when the cooking container 4 is stored in the grill chamber 20. Therefore, when the lower burner 23 is ignited, a flame is formed in the flame holes 230, and combustion exhaust gas and radiant heat are released toward the center and lower left and right of the grill chamber 20, heating the cooking container 4 from the side. Although not shown, the lower burner 23 has a venturi part extending backward from the rear wall 205 of the grill chamber 20 at its rear part. A gas nozzle is inserted into the opening at the rear end of the venturi part. Therefore, when fuel gas is ejected from the gas nozzle toward the opening of the venturi section, the fuel gas is sucked into the venturi section together with the air surrounding the opening, and a mixture of fuel gas and primary air is generated and supplied to the burner hole 230.

2 and 3, a generally rectangular air intake 24 that is long in the front-rear direction is provided in the approximately vertical center of the side wall 203. As a result, secondary air for combustion in the lower burner 23 is taken into the grill chamber 20 from outside the grill chamber 20 through the air intake 24 due to the draft effect when the combustion exhaust gas in the grill chamber 20 is exhausted to the outside of the gas stove 1 through the exhaust passage 300. A secondary air guide plate 26 is provided above the air intake 24 on the inner surface of the side wall 203 to guide the secondary air taken into the grill chamber 20 from the air intake 24 into the inside of the grill chamber 20 through the periphery of the flame hole 230 of the lower burner 23.

The secondary air guide plate 26 is inclined downward from the upper edge of the air intake 24 toward the inside of the grill chamber 20, and protrudes further inward into the grill chamber 20 than the position of the flame holes 230 of the lower burner 23. Therefore, the secondary air taken into the grill chamber 20 from the air intake 24 is guided along the lower surface of the secondary air guide plate 26 to above the lower burner 23, and then from above the flame holes 230 to the lower center of the left and right of the grill chamber 20. For example, when a grill net is stored in the grill chamber 20, the flame formed in the flame holes 230 rides on the flow of this secondary air and extends toward the center of the left and right of the grill chamber 20, causing the combustion exhaust gas to reach the center of the left and right of the grill chamber 20.

The afterburner 7 is a surface combustion type burner whose upper surface is made of a metal combustion plate, and a large number of flame holes 70 are opened over almost the entire upper surface of the plate body. Therefore, when the afterburner 7 is ignited, a flame is formed over the entire upper surface of the plate body, and the combustion exhaust gas and radiant heat are emitted toward the upper side of the exhaust passage 300, and the oil smoke and odor components contained in the combustion exhaust gas flowing into the exhaust passage 300 from inside the grill chamber 20 are burned. The afterburner 7 has a venturi part 71 that extends almost horizontally from below the bottom wall 31 of the exhaust duct 30 to the right outer side. Although not shown, a gas nozzle is inserted into the opening 72 that opens at the outer end of the venturi part 71. Therefore, when fuel gas is ejected from the gas nozzle toward the opening 72 of the venturi part 71, the fuel gas is sucked into the venturi part 71 together with the air around the opening 72, and a mixture of fuel gas and primary air is generated and supplied to the flame hole 70.

In the vicinity of the flame holes 220, 230 of the upper and lower burners 22, 23, there are provided an upper burner ignition plug 51 and a lower burner ignition plug 52 that discharge sparks toward the periphery of the corresponding flame holes 220, 230 when a high voltage is applied from an igniter described later, and an upper burner thermocouple 53 and a lower burner thermocouple 54 as flame detection sensors that detect the presence or absence of a flame in the corresponding flame holes 220, 230. In addition, an afterburner ignition plug 55 and an afterburner thermocouple 56 are similarly provided in the vicinity of the flame holes 70 on both the left and right ends of the upper surface of the afterburner 7, respectively. In addition, an internal temperature sensor 57 that detects the temperature inside the grill chamber 20 is provided below the left and right center of the rear wall 205 inside the grill chamber 20.

As shown in FIG. 3, a metal side cover 60 is provided on the outside of the right side wall 203 of the grill chamber 20. The metal side cover 60 is generally inverted L-shaped in cross section in the left-right direction and covers the entire air intake 24 opening in the right side wall 203 at a predetermined distance from above, the front, and the right outer side, and is open downward and rearward.

The side cover 60 has an upper wall portion 61 that extends outward from the outer surface of the right side wall 203 above the air intake 24, an outer wall portion 62 that hangs down from the outer end of the upper wall portion 61, and a front wall portion (not shown) that bends and extends inward from the front end of the outer wall portion 62. Therefore, when the draft effect occurs, air from inside the gas stove 1 flows into the side cover 60 mainly from the lower opening 65 of the side cover 60, and an air flow path is formed inside the side cover 60 for air to flow from below toward the air intake 24.

On the other hand, when the temperature inside the grill chamber 20 is low, such as at the beginning of ignition, and the pressure inside the grill chamber 20 is high, the draft effect is not sufficient, and the combustion exhaust gas leaks from the air intake 24 into the side cover 60. However, because the front, upper, and right outer sides of the side cover 60 are blocked, the combustion exhaust gas leaking from the air intake 24 into the side cover 60 is mainly guided to the rear opening and flows out rearward from the rear opening.

Returning to FIG. 1, the operation section 36 formed on the left side of the grill door 21 is provided with a grill switch 17 that has the functions of turning on and off the upper and lower burners 22, 23 and adjusting the heat, and a kangaroo-style operation unit 38 below it. Although not shown, the operation unit 38 is provided with a touch panel type operation switch section and display section. The operation switch section includes, for example, an auto menu switch for selecting a container cooking mode in which a cooking container 4 containing food to be cooked is placed in the grill chamber 20 and cooked, a cooking selection switch for performing timer cooking with a set cooking time from the container cooking mode or for selecting the type of cooking, and a cooking time setting switch for setting the cooking time when performing timer cooking in the container cooking mode.

Figure 4 is a block diagram of the gas stove 1 of this embodiment. The gas stove 1 also has a stove burner 5, but only the grill 2 will be described below, and the stove burner 5 will not be described or illustrated. As shown in Figure 4, a gas pipe 80 is arranged inside the stove body 10 to guide fuel gas supplied from the gas main pipe to each burner 22, 23, 7. The gas pipe 80 is also provided with electromagnetic opening and closing valves 82, 83, 84 that can cut off the supply of gas to the corresponding burners 22, 23, 7, and flame power switching valves 85, 86 that can adjust the amount of gas supplied to the corresponding burners 22, 23. Although not shown, the flame power switching valves 85, 86 are valve devices composed of an opening and closing valve and a bypass passage, and by closing the opening and closing valve, fuel gas is supplied only from the bypass passage to the downstream side, causing the corresponding burners 22, 23 to burn at a low flame. On the other hand, by opening the on-off valve, fuel gas is supplied downstream from both the on-off valve and the bypass passage, causing the corresponding burners 22 and 23 to burn at high flames.

The stove body 10 incorporates a control device 9, which is a control unit that controls the operation of the entire gas stove 1. The igniter 58, upper and lower burner thermocouples 53, 54, afterburner thermocouple 56, internal temperature sensor 57, solenoid valves 82, 83, 84, heat power switching valves 85, 86, grill switch 17, operation switch section and display section of the operation unit 38, and speaker 39 are connected to the control device 9 via electrical wiring.

The control device 9 incorporates a microcomputer in which a control program is stored, and the microcomputer has a combustion control unit that controls the ignition, extinguishing, and fire power of the burners 22, 23, and 7 in response to the operation of the grill switch 17 and the operating switch unit; a first lower ignition condition judgment unit that judges whether a predetermined time difference ignition threshold time has elapsed since the ignition of the afterburner 7 was detected by the afterburner thermocouple 56; a second lower ignition condition judgment unit that judges whether the internal temperature detected by the internal temperature sensor 57 is equal to or higher than a predetermined time difference ignition threshold temperature; an ignition judgment unit that judges the ignition of each burner 22, 23, and 7 based on the output values of the upper and lower burner thermocouples 53 and 54 and the output value of the afterburner thermocouple 56; a misfire judgment unit that judges the misfire of the burners 22, 23, and 7 based on the output values of the upper and lower burner thermocouples 53 and 54 and the output value of the afterburner thermocouple 56; and a timing unit. The microcomputer memory also stores predetermined judgment times and judgment values for judging ignition failure of burners 22, 23, and 7, and misfire during combustion of burners 22, 23, and 7, as well as setting values for burning burners 22, 23, and 7 in a predetermined combustion pattern when the auto menu switch is selected and container cooking mode is selected.

Next, we will explain the control operation of the ignition process at the start of cooking when the cooking container 4 is placed on the grill 2 of the gas stove 1 of this embodiment and cooking is performed in container cooking mode.

FIG. 5 is a flow chart showing the control operation of an ignition processing program in the gas stove 1 of the present embodiment.
When the user selects, for example, the container cooking mode and timer cooking with the operation switch section, sets the cooking time, and operates the grill switch 17 to turn on the stove, the ignition timer starts to count the predetermined ignition time (for example, 10 seconds) (step S1). Next, the igniter 58 is operated, and the electromagnetic valves 82 and 84 are opened. Furthermore, the heat power switching valve 85 is opened to turn on the stove so that the stove is in high flame combustion, and the ignition process of the upper burner 22 and the afterburner 7 is started (step S2).

As described above, the ignition process for the upper burner 22 and the afterburner 7 is started, and if the output values of the upper burner thermocouple 53 and the afterburner thermocouple 56 do not reach or exceed a predetermined ignition detection threshold (e.g., 2.5 mV) before the ignition timer times out (No in step S3, Yes in step S4), the igniter 58 is stopped, it is determined that an ignition failure has occurred, and an ignition error for the upper burner 22 and the afterburner 7 is notified from the display unit and speaker 39 (steps S5 to S6). The ignition detection thresholds for each burner 22, 7 may be the same or different.

On the other hand, if the output values of the upper burner thermocouple 53 and the afterburner thermocouple 56 reach or exceed the ignition detection threshold before the ignition timer times out (Yes in step S3), the igniter 58 is stopped, a time-difference ignition timer is started to count the predetermined time-difference ignition threshold time (e.g., 20 seconds) for igniting the lower burner 23, and monitoring of the internal temperature detected by the internal temperature sensor 57 is started (steps S7 to S8).

Then, when the time-difference ignition timer expires (Yes in step S9), or when the internal temperature reaches or exceeds a predetermined time-difference ignition threshold temperature (e.g., 60°C) before the time-difference ignition timer expires (No in step S9, Yes in step S10), the lower-fire ignition timer for the lower-fire burner 23 is started (step S11). The igniter 58 is also operated, the electromagnetic on-off valve 83 is opened, and the on-off valve of the heat power switching valve 86 is opened to achieve high-flame combustion, starting the ignition process for the lower-fire burner 23 (step S12).

If the ignition process for the lower burner 23 is started as described above, and the output value of the lower burner thermocouple 54 does not reach or exceed a predetermined ignition detection threshold (e.g., 2.5 mV) before the lower burner ignition timer times out (No in step S13, Yes in step S14), the igniter 58 is stopped, it is determined that an ignition failure has occurred, and an ignition error for the lower burner 23 is notified via the display unit and speaker 39 (steps S15 to S16).

On the other hand, if the output value of the lower burner thermocouple 54 reaches or exceeds the ignition detection threshold before the lower burner ignition timer times out (Yes in step S13), the igniter 58 is stopped, and the heat of the burners 22, 23, and 7 is adjusted according to the combustion pattern set in the container cooking mode to perform cooking (steps S17 to S18).

According to the grill 2, the afterburner 7 is ignited before the lower burner 23 when cooking begins, so that the draft effect of exhausting the combustion exhaust gas to the outside from the exhaust passage 300 is easily achieved. In addition, the grill 2 has an upper burner 22, and the upper burner 22 is also ignited before the lower burner 23, so that the temperature inside the grill chamber 20 can be raised in a shorter time, and the draft effect is more easily achieved. According to the grill 2, the lower burner 23 is ignited after the lower ignition condition is satisfied, either the first lower ignition condition in which the output value of the afterburner thermocouple 56 becomes equal to or greater than the ignition detection threshold and the time difference ignition threshold time passes, or the second lower ignition condition in which the output value of the afterburner thermocouple 56 becomes equal to or greater than the ignition detection threshold and the temperature inside the grill chamber 20 becomes equal to or greater than the time difference ignition threshold temperature, so that the lower burner 23 can be ignited in a state where the draft effect is sufficiently generated. Therefore, it is possible to suppress the leakage of combustion exhaust gas from the air intake 24 into the stove body 10 when the lower burner 23 is ignited. As a result, even if the afterburner 7 has a venturi portion 71 extending behind the side cover 600 from which the combustion exhaust gas flows out, the amount of combustion exhaust gas taken in from the opening 72 of the venturi portion 71 of the afterburner 7 at the beginning of ignition can be reduced, so that ignition failure of the afterburner 7 can be prevented and the afterburner 7 can start burning stably. In this embodiment, both the first lower ignition condition and the second lower ignition condition are set, but only one of the lower ignition conditions may be set.

(Embodiment 2)
The gas stove of this embodiment has the same configuration as the gas stove of embodiment 1, except that it has a control program for starting ignition processing of the lower burner as well as the upper burner and afterburner when cooking begins, instead of the ignition processing program of embodiment 1. For this reason, the same reference numbers are used for the same configuration, and explanations are omitted.

FIG. 6 is a flow chart showing the control operation of an ignition processing program in the gas stove 1 of the present embodiment.
As in the first embodiment, when the user selects the container cooking mode and timer cooking with the operation switch section, sets the cooking time, and performs the ignition operation with the grill switch 17, the first ignition determination timer is started for timing a predetermined first ignition determination time (for example, 10 seconds) (step S31). Next, the igniter 58 is operated, and the electromagnetic opening/closing valves 82, 83, and 84 are opened, and the opening/closing valves of the heat power switching valves 85 and 86 are opened to perform high-flame combustion, thereby starting the ignition process of the upper and lower fire burners 22 and 23 and the afterburner 7 (step S32).

When the ignition process for each burner 22, 23, 7 is started as described above and the output values of the upper and lower burner thermocouples 53, 54 and the afterburner thermocouple 56 reach or exceed a predetermined ignition detection threshold (e.g., 2.5 mV) (Yes in steps S33 and S37), the igniter 58 is stopped and the heat of the burners 22, 23, 7 is adjusted according to the combustion pattern set in the container cooking mode to perform cooking (steps S38 to S39).

If the output value of either of the upper and lower burner thermocouples 53, 54 does not reach or exceed the ignition detection threshold before the first ignition determination timer times out (No in step S33, Yes in step S34), the igniter 58 is stopped, it is determined that an ignition failure has occurred, and an ignition error of the upper and lower burners 22, 23 is notified via the display unit and speaker 39 (steps S35 to S36).

On the other hand, if the output values of the upper and lower burner thermocouples 53, 54 are equal to or greater than the ignition detection threshold before the first ignition judgment timer times out, but the output value of the afterburner thermocouple 56 is not equal to or greater than the ignition detection threshold (Yes in step S33, No in step S37, Yes in step S40), the on-off valve of the heat power switching valve 86 is closed to reduce the amount of fuel gas supplied to the lower burner 23 so that low-flame combustion is performed, and a second ignition judgment timer is started to count a predetermined second ignition judgment time (e.g., 20 seconds) (steps S41 to S42).

Next, in the same manner as above, it is determined whether the output values of the upper and lower burner thermocouples 53, 54 and the afterburner thermocouple 56 are equal to or greater than the ignition detection threshold (steps S43 and S47). If the output values of the upper and lower burner thermocouples 53, 54 and the afterburner thermocouple 56 are equal to or greater than the ignition detection threshold (Yes in steps S43 and S47), the heat of the lower burner 23 is reduced, reducing the leakage of combustion exhaust gas from the air intake 24 into the stove body 10, and the afterburner 7 is considered to have ignited normally. Therefore, the igniter 58 is stopped, the on-off valve of the heat switching valve 86 is opened again to increase the supply of fuel gas to the lower burner 23 so that strong combustion is performed, and the heat of the burners 22, 23, and 7 is adjusted according to the set combustion pattern to perform cooking (steps S48 to S50).

When the second ignition determination timer times out, if the output value of either of the upper and lower burner thermocouples 53, 54 falls below the ignition detection threshold (No in step S43, Yes in step S44), the igniter 58 is stopped, it is determined that an ignition failure has occurred, and an ignition error of the upper and lower burners 22, 23 is notified from the display unit and speaker 39 (steps S45 to S46).

In addition, even if the heat of the lower burner 23 is reduced, if the output value of the afterburner thermocouple 56 does not reach or exceed the ignition detection threshold before the second ignition determination timer times out (No in step S47, Yes in step S51), it is determined that an ignition failure has occurred, the igniter 58 is stopped, and an ignition error of the afterburner 7 is announced via the display unit and speaker 39 (steps S52 to S53).

According to the above grill 2, not only the afterburner 7 but also the lower burner 23 is ignited when cooking begins, which reduces the discomfort felt by the user when performing the ignition operation. On the other hand, if the lower burner 23 and the afterburner 7 are ignited when cooking begins, when the draft effect is not sufficient, the amount of combustion exhaust gas leaking from the air intake 24 into the stove body 10 increases, which makes it easy for the afterburner 7 to fail to ignite. However, according to the above grill 2, if the output value of the afterburner thermocouple 56 does not reach or exceed the ignition detection threshold within the first ignition judgment time after the afterburner 7 is ignited, the firepower of the lower burner 23 is reduced, which reduces the leakage of combustion exhaust gas from the air intake 24 into the stove body 10 due to the ignition of the lower burner 23. According to the grill 2, after reducing the heat of the lower burner 23, if the output value of the afterburner thermocouple 56 becomes equal to or greater than the ignition detection threshold within the second ignition judgment time, the heat of the lower burner 23 is increased, so that cooking can be started smoothly while preventing ignition failure of the afterburner 7.

(Embodiment 3)
The gas stove of this embodiment has the same configuration as the gas stove of the first embodiment, except that it has a control program that performs a process to prevent afterburner misfire when the combustion of the afterburner becomes unstable during cooking. For this reason, the same reference numbers are used for the same configurations, and a description thereof will be omitted. In this gas stove, when a misfire determination condition is met in which the output value of each thermocouple 53, 54, 56 falls below a predetermined misfire determination threshold (e.g., 2.5 mV) for a predetermined misfire determination time (e.g., 3 seconds) or more, a misfire of each burner 22, 23, 7 is determined. This makes it possible to reliably determine misfire of each burner 22, 23, 7 even when a grill that does not leak much combustion exhaust gas from the air intake 24 into the stove body 10 is used during cooking. The misfire determination threshold may be the same as or different from the ignition detection threshold described above.

FIG. 7 is a flowchart showing the control operation of the misfire prevention processing program in the gas stove 1 of this embodiment.
When the ignition processing program of the first embodiment is executed and each burner 22, 23, 7 is normally ignited (step S71), the output value of each thermocouple 53, 54, 56 is monitored. Then, during cooking, when the output value of the afterburner thermocouple 56 falls to a predetermined oxygen deficiency judgment threshold (e.g., 4 mV) higher than the misfire judgment threshold (No in step S72), the on-off valve of the heat power switching valve 86 is closed to reduce the supply of fuel gas to the lower burner 23 so as to perform low-flame combustion (step S73).

Then, after reducing the heat of the lower burner 23, if the output value of the afterburner thermocouple 56 returns to above the oxygen deficiency judgment threshold (Yes in step S74), it is considered that reducing the heat of the lower burner 23 has reduced the leakage of combustion exhaust gas from the air intake 24 into the stove body 10 and stabilized the combustion in the afterburner 7, so the on-off valve of the heat switching valve 86 is opened to increase the amount of fuel gas supplied to the lower burner 23 so that strong combustion is achieved (step S75).

If the output value of the afterburner thermocouple 56 does not return to above the oxygen deficiency judgment threshold after the flame power of the underfire burner 23 is reduced (No in step S74), the misfire of the afterburner 7 is judged under a predetermined blunted misfire judgment condition that is a blunted misfire judgment condition (step S76). This blunted misfire judgment condition judges whether the state in which the output value of the afterburner thermocouple 56 falls below the misfire judgment threshold in the misfire judgment condition continues for a predetermined blunted misfire judgment time (e.g., 10 seconds) that is longer than the misfire judgment time. The blunted misfire judgment condition may be set to a blunted misfire judgment time that is longer than the misfire judgment time, or may be set to a blunted misfire judgment threshold (e.g., 2.3 mV) that is lower than the misfire judgment threshold, or may be set to a condition in which both the misfire judgment time and the misfire judgment threshold are blunted.

At this time, if the blunting misfire judgment condition is met (Yes in step S76), the fire power of the lower burner 23 is reduced, and since it is considered that the afterburner 7 will not return to normal combustion even if the blunting misfire judgment condition is met, the electromagnetic opening and closing valves 82, 83, and 84 are closed to extinguish the burners 22, 23, and 7, and the display unit and speaker 39 are made to notify the mid-way misfire of the afterburner 7 (steps S77 to S78). Also, even if the output value of the afterburner thermocouple 56 does not return to the oxygen deficiency judgment threshold or higher, if the blunting misfire judgment condition is not met (No in steps S74 and S76), it is considered that a certain flame is formed in the afterburner 7, so the lower burner 23 is burned with a reduced fire power until a stable flame is formed in the afterburner 7. This makes it possible to prevent interruption of cooking when the upper and lower burners 22 and 23 are burning normally.

During cooking, if the output value of the afterburner thermocouple 56 is equal to or greater than the oxygen deficiency judgment threshold, but the misfire judgment condition is met in either the upper or lower burners 22, 23 (Yes in step S72, Yes in step S81), the burners 22, 23, 7 are extinguished, and the display unit and speaker 39 notify the user of the misfire in the upper or lower burners 22, 23 (steps S82 to S83).

When cooking with the underburner 23 and afterburner 7 burning, if the internal pressure in the grill chamber 20 increases, exhaust combustion gas may leak from the air intake 24 into the stove body 10, causing the afterburner 7 flame to lift or some of the flame to blow away, which may result in a decrease in the output value detected by the afterburner thermocouple 56.

However, according to the above grill 2, during cooking with the underburner 23 and afterburner 7 burning, the output value of the afterburner thermocouple 56 is higher than the misfire judgment threshold in the misfire judgment conditions, but when it falls to the oxygen deficiency judgment threshold, the heat of the underburner 23 is reduced, so that the leakage of combustion exhaust gas from the air intake 24 into the stove body 10 during cooking can be reduced. And, according to the above grill 2, after the heat of the underburner 23 is reduced, when the output value of the afterburner thermocouple 56 returns to above the oxygen deficiency judgment threshold, the heat of the underburner 23 is increased, so that cooking can be continued smoothly while preventing misfire of the afterburner 7 during cooking.

In addition, when the afterburner 7 burns due to lack of oxygen, the output value of the afterburner thermocouple 56 decreases because a flame lift or a part of the flame is blown away, but a certain flame may be formed in the left and right central areas other than the flame hole 70 detected by the afterburner thermocouple 56. On the other hand, according to the above grill 2, when the output value of the afterburner thermocouple 56 decreases to the oxygen deficiency judgment threshold, the fire power of the lower burner 23 is reduced, so that even if the output value of the afterburner thermocouple 56 temporarily decreases significantly, the leakage of combustion exhaust gas from the air intake 24 into the stove body 10 is reduced, improving the oxygen deficiency combustion of the afterburner 7, and the afterburner 7 can be restored to normal combustion. Therefore, by slowing down the misfire judgment condition of the afterburner 7, it is possible to prevent the afterburner 7 from misfiring midway and continue cooking smoothly. Note that the ignition processing program of the second embodiment may be executed instead of the ignition processing program of the first embodiment.

Reference Signs List 1 Gas stove 2 Grill 7 Afterburner 9 Control device 10 Stove body 20 Grill chamber 23 Underburner 24 Air intake 56 Afterburner thermocouple 300 Exhaust passage

Claims (6)

A grill chamber accommodated in the cooking device body;
A lower fire burner provided in the grill chamber;
An exhaust passage for discharging combustion exhaust gas from inside the grill chamber to the outside;
an afterburner provided in the exhaust passage;
an afterburner thermocouple for detecting an afterburner flame;
A control unit that controls the combustion of the underburner and the afterburner,
A grill having an air intake opening on a side wall of the grill chamber for supplying secondary air to a lower burner,
The control unit initiates the ignition process of the afterburner when cooking begins, and then ignites the underburner. 2. The grill of claim 1,
The control unit ignites the lower burner when at least one of the following lower ignition conditions is satisfied: a first lower ignition condition in which an afterburner ignition process is started at the start of cooking and a predetermined time-lag ignition threshold time elapses after the output value of the afterburner thermocouple becomes equal to or greater than a predetermined ignition detection threshold, or a second lower ignition condition in which an afterburner ignition process is started at the start of cooking and the temperature inside the grill chamber becomes equal to or greater than a predetermined time-lag ignition threshold temperature after the output value of the afterburner thermocouple becomes equal to or greater than a predetermined ignition detection threshold. A grill chamber accommodated in the cooking device body;
A lower fire burner provided in the grill chamber;
An exhaust passage for discharging combustion exhaust gas from inside the grill chamber to the outside;
an afterburner provided in the exhaust passage;
an afterburner thermocouple for detecting an afterburner flame;
A control unit that controls the combustion of the underburner and the afterburner,
A grill having an air intake opening on a side wall of the grill chamber for supplying secondary air to a lower burner,
The control unit starts the ignition process of the lower burner and the afterburner at the start of cooking, and then reduces the heat of the lower burner if the output value of the afterburner thermocouple does not become equal to or greater than a predetermined ignition detection threshold within a predetermined first ignition judgment time.
A grill that, after reducing the heat of the lower burner, increases the heat of the lower burner if the output value of the afterburner thermocouple becomes equal to or greater than the ignition detection threshold within a second predetermined ignition determination time. A grill chamber accommodated in the cooking device body;
A lower fire burner provided in the grill chamber;
An exhaust passage for discharging combustion exhaust gas from inside the grill chamber to the outside;
an afterburner provided in the exhaust passage;
an afterburner thermocouple for detecting an afterburner flame;
A control unit that controls the combustion of the underburner and the afterburner,
A grill having an air intake opening on a side wall of the grill chamber for supplying secondary air to a lower burner,
The control unit determines that the afterburner has misfired during cooking while the underburner and the afterburner are burning, when a misfire determination condition is met in which a state in which an output value of the afterburner thermocouple falls below a predetermined misfire determination threshold continues for a predetermined misfire determination time or longer,
During cooking with the lower burner and the afterburner burning, when the output value of the afterburner thermocouple is higher than the misfire judgment threshold in the misfire judgment condition but falls to a predetermined oxygen deficiency judgment threshold, the heat of the lower burner is reduced,
A grill that, after reducing the power of the lower burner, increases the power of the lower burner when the output value of the afterburner thermocouple returns to or exceeds the oxygen deficiency determination threshold. 5. The grill of claim 4,
A grill in which the control unit relaxes the afterburner misfire determination condition if the output value of the afterburner thermocouple does not return to above the oxygen deficiency determination threshold even when the heat of the lower burner is reduced. A grill according to any one of claims 1 to 5,
A grill that has a container cooking mode in which a cooking container is stored inside the grill chamber and cooked.