JPH0141005Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an ignition control device for a combustion burner.

In general, combustion burners are used when the outside temperature is, for example,
At 25°C, even if fuel supply starts at the same time as air supply starts, that is, even if the fuel supply delay time is set to 0, the probability of fuel ignition is close to 1. However,
If the outside air temperature drops, if the delay time is set to 0, the probability of fuel ignition will decrease. Therefore, the delay time is maintained at a certain value in preparation for when the outside air temperature drops.

A conventional combustion burner ignition control device based on this idea is shown in FIG. That is, the battery 10, the switch 20, and the glow plug 30 for igniting fuel are connected in series. Fan 4 also sends air into the combustion chamber.
The fan motor 40 that rotates the glow plug 3
0 and connected in parallel.

The fuel pump 50 is configured to operate with a certain time delay due to a delay circuit 60. This delay circuit 60 consists of a fixed resistor 61 and a capacitor 62, and their connection point is designated as P. The base of the transistor 70 is connected to this point P,
A coil of a normally open relay 71 is connected between the collector and the switch 20.

The normally open contact of the relay 71 and the fuel pump 50
connected in series. In addition, 63 is the capacitor 6
This is a high impedance resistor provided for discharging the charges accumulated in the 2.

Next, the operation of the above conventional example will be explained. First, when the switch 20 is off, the capacitor 62 is not charged and the transistor 70 is off, so the relay 71 is open and the fuel pump 50 is not operating.

When the switch 20 is turned on, the glow plug 30 is preheated for a certain period of time, and the fan motor 4
As the engine 0 rotates, air is supplied to the combustion chamber by the fan 41. At the same time, fixed resistance 6
1 begins to charge capacitor 62. After a certain delay time has elapsed from this point, the P point voltage reaches a value sufficient to turn on the transistor 70, so the transistor 70 is turned on. This closes the normally open relay 71 and the fuel pump 50 starts operating.

That is, from when the fan 41 starts supplying air to the combustion chamber, fuel is supplied to the combustion chamber with a certain time delay. This increases the probability of fuel ignition to some extent even if the outside temperature is low. The fuel pump 50 is configured to pressurize the fuel and then spray the fuel in a mist form from a spray nozzle.

However, in the conventional example described above, since the delay time by the delay circuit 60 is constant, there remains a problem that the probability of fuel ignition is not sufficiently high when the outside temperature changes.

In other words, at a certain temperature where the outside air temperature is below room temperature, the delay time is appropriate.
The probability of fuel ignition is close to 1. However, for other outside temperatures, the probability of ignition is low.

Therefore, in order to improve the probability of fuel ignition when the outside temperature changes, the present invention atomizes liquid fuel using a fuel pump, and combines this mist fuel with air supplied by a blower into the combustion chamber. In a combustion type burner that mixes and burns air, a temperature sensor detects the temperature of air supplied by the blower, and if the temperature of the air supplied by the blower is lower than a predetermined temperature, A timing adjustment circuit that delays the start time of fuel spraying by the fuel pump in accordance with the temperature of the air detected by the temperature sensor relative to the start time of air supply to the combustion chamber by the blower. It is.

The present invention will be described in detail below based on embodiments shown in the accompanying drawings. Components that are the same as those shown in FIG. 1 are designated by the same reference numerals, and their explanations are omitted.

The delay circuit 80 includes a temperature sensor 8 such as a thermistor.
1 and a capacitor 82. This temperature sensor 81 is provided at a position where it can detect the outside air temperature, that is, at a position where it can detect the temperature of the air supplied to the combustion chamber. Temperature sensor 81 and capacitor 8
The connection point with 2 is P, and 83 is a high impedance resistor for discharging.

Next, the operation of the above embodiment will be explained. First, when the switch 20 is off, the fan 41 and the fuel pump 50 are stopped, as in the conventional example. Now, when the switch 20 is turned on, the fan 41 rotates, so air is supplied to the combustion chamber. Then, after a predetermined delay time from that time, fuel is supplied to the combustion chamber by the fuel pump 50. Here, when the outside air temperature is a little lower than 25° C., the delay time determined by the delay circuit 80 is relatively short, so the delay time of fuel supply is also relatively short. If the outside temperature is significantly lower than 25°C, the fuel supply delay time will also be significantly delayed. The outside air temperature and the fuel supply delay time change continuously, as shown in FIG. Therefore, no matter how the outside air temperature changes, it is possible to obtain a fuel supply delay time that is most suitable for the outside air temperature, and the probability of fuel ignition is extremely high.

Next, when switch 20 is turned off, capacitor 8
2 is discharged through the resistor 83, returning to the initial state.

In the above embodiment, a thermistor was used as the element for detecting the outside temperature, but other elements may be used, and the delay circuit for obtaining the delay time of fuel supply may be different from the above. It may be hot. In the embodiment described above, a delay circuit including a capacitor and a resistor is used, but the delay circuit may also be configured by, for example, an oscillation circuit and a counter for counting future output pulses.

Further, in the embodiment described above, the fuel supply timing is delayed with respect to the air supply to the combustion chamber, but it is not necessarily necessary to delay the fuel supply timing in this way. That is, if the temperature of the supplied air exceeds a predetermined temperature, the probability of ignition will increase if the air supply timing is delayed relative to the fuel supply timing. This is illustrated when the delay time becomes negative on the characteristic line A in FIG.

Further, in the case of characteristic line A, the fuel supply timing is delayed compared to the air supply at temperatures below 25° C., and at temperatures higher than that, the starting order of the air supply and fuel supply timing is reversed. The reason why the supply start order changes like this is because the temperature of the supply air changes.
In addition to the case of 25°C, depending on the situation, the temperature may be 15°C as shown in the characteristic shown by broken line B, for example.

As described above, the present invention provides a combustion type burner in which liquid fuel is atomized by a fuel pump, and this atomized fuel is mixed with air supplied by a blower in a combustion chamber and burned. a temperature sensor for detecting the temperature of the air supplied by the blower; and a temperature sensor for detecting the temperature of the air supplied by the blower; and a timing adjustment circuit that delays the start timing of fuel spray by the fuel pump according to the temperature of the air detected by the temperature sensor, so that the probability of fuel ignition can be improved in a wide range of outside temperature ranges. .

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing a conventional ignition control device for a combustion type burner, Fig. 2 is a circuit diagram showing an embodiment of the present invention, and Fig. 3 is a delay time of fuel supply with respect to air supply in the above embodiment. This is a graph showing. 30... Glow plug, 41... Juan, 50
... Fuel pump, 60, 80 ... Delay circuit, 81
...Temperature sensor, 82...Capacitor.

Claims (1)

[Scope of Claim for Utility Model Registration] A combustion type burner in which liquid fuel is atomized by a fuel pump, and the atomized fuel is mixed with air supplied by a blower in a combustion chamber and burned. a temperature sensor for detecting the temperature of the air supplied by the blower; and a timing adjustment circuit for delaying the start timing of fuel spray by the fuel pump in accordance with the temperature of air detected by the temperature sensor.