JPH02287013A - Combustion controller - Google Patents

Abstract

PURPOSE:To stabilize the combustion all over the combustion range of a combustion apparatus such as a warm air heater, etc. with avoiding influences of differences in the altitude by shifting the characteristics of the air flow rate versus the fuel feed rate corresponding to detected atmostpheric pressure. CONSTITUTION:A combustion rate is determined according to the load and within a range between minimum and maximum combustion rates set by minimum and maximum combustion rate setters 17 and 18. The rotating speed of a burner motor BM is controlled so that the air flow rate is controlled to a flow rate suitable for the combustion rate, and the frequency of a fuel pump is controlled so that the fuel feed rate is regulated to a feed rate corresponding to the air flow rate. On the other hand, the atmospheric pressure is detected by a pressure detector 19, and inputs to an air-fuel ratio correcting device 13. The air-fuel ratio correcting device 13 shifts the fuel feed rate versus the combustion rate characteristic curve L, which is determined corresponding to the load, corresponding to the detected pressure. That is, in case of low pressure, it is shifted to the characteristic curve L2 or L4 by which the air ratio increases, and on the contrary, in case of high pressure, it is shifted to the characteristic curve L1 or L3. By this constitution, a stable combustion is always maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION B) Industrial Application Field This invention relates to a combustion control device used in hot air heaters, water heaters, etc. that use kerosene or gas as fuel.

(b) Conventional technology Conventionally, as disclosed in Japanese Patent Publication No. 62-33496, for example, in a hot air heater using a gasification type burner that gasifies and burns liquid fuel such as kerosene, By controlling the rotation speed of the burner motor according to the heating load and increasing/decreasing the amount of oil sent by the combustion pump according to the rotation speed of the burner motor, the air-fuel ratio is kept approximately constant and the combustion state of the burner is maintained in good condition. The amount of combustion can be switched between strong and weak.

c) Problems to be solved by the invention By the way, the above-mentioned heaters are sometimes installed at high altitudes, and in that case, the air-fuel ratio collapses as the absolute amount of air decreases, causing the combustion state to deteriorate. I was worried that it would get worse.

This invention was made in view of the above facts,
This is to ensure good combustion over the entire combustion range, regardless of changes in the absolute amount of air due to differences in altitude, etc.

(d) Means for solving the problem In this invention, combustion control is performed to control the amount of air blown and the amount of fuel supplied according to the characteristics of the amount of air blown and the amount of fuel supplied, which are predetermined so that the air-fuel ratio becomes substantially constant. The device is provided with a detector for detecting atmospheric pressure and an adjusting means for changing the characteristics according to the atmospheric pressure detected by the detector.

(f) Effect With this configuration, the amount of combustion air and the amount of combustion change depending on the size of the load, and the amount of combustion in the burner is increased or decreased while keeping the air-fuel ratio approximately constant, so that the amount of combustion in the burner is increased or decreased in accordance with the load. Not only does combustion occur at the optimum air-fuel ratio, but the amount of air flow and fuel supply can be adjusted over the entire combustion range in response to changes in the absolute amount of air due to differences in altitude and pressure, and combustion is always performed at the optimal air-fuel ratio. It will be done.

(f) Example Next, embodiments of the present invention shown in the drawings will be described.

Figure 4 shows an outdoor air supply/exhaust type heater to which this invention is applied; (1) shows the burner (2);
), the heat exchanger (3), the blower fan (4), and the fuel oil in the cartridge tank (not shown) are transferred to the burner (2).
The main body of the heating machine, which houses the fuel pump (5) etc. that sends oil to the
(6) is installed through the wall (7), and the air supply path (6
(8) is an air supply pipe for guiding outdoor air that has flowed into the air supply path (6A) to the burner (2), (9) is a heat exchanger (3)
The exhaust gas heat-exchanged is transferred to the exhaust path (6B
) is an exhaust pipe that leads to the In the heater body (1), the indoor air sucked in from the upper part of the back by the blower fan (4) is heated by heat exchange with the combustion gas in the heat exchanger (3), and the warm air is blown out at the lower part of the front [1 (10 ) is discharged into the room as warm air. 6 FIG. 1 shows the combustion control device for the above-mentioned heater. In FIG. 1, (11) is a microcomputer, (12) and 13) are a combustion amount control means and an air-fuel ratio correction means, respectively, which are built into the micro:1 bicycle taxi 11>, (14) is an operation switch, and (15) is a ) is a temperature setting device to set the desired indoor temperature, (16) is a room temperature sensor such as a thermistor, (17)
is a minimum combustion amount setting device such as a semi-fixed resistance, <18> is a maximum combustion amount setting device such as a semi-fixed resistance, (19) is a pressure detector that detects the pressure of outdoor air, (BM) is a burner motor, (2)
0) is a rotation speed detector that detects the rotation speed of the burner motor (BM), (21) is a vaporization heater, (22) is a spark plug, and (FM) is a blower motor for driving the blower fan (4).

As shown in FIG. 2, the combustion amount control means uses a minimum combustion amount setter <17) and a maximum combustion amount setter (18) to set the minimum value (Q, , , ) and maximum value ( q,
Ax) is determined in advance, and the combustion amount is proportionally controlled continuously or in multiple stages depending on the load. When the operation switch (14) is turned on, first, the vaporization heater (21) is energized. When the burner (2) carburetor cylinder (not shown) is confirmed to have been sufficiently heated by a temperature signal from a burner thermistor (not shown), etc., the burner motor (2) and fuel pump (5) are started in sequence. Furthermore, the spark plug (22) is operated to cause combustion to occur in the burner (2).Also, while the operation switch (14) is turned on, the desired temperature and room temperature set by the temperature setting device (15) are set. The temperature difference between the room temperature detected by the sensor (16) and the second
Determine the combustion amount Q appropriate for the size of the load according to the diagram. Then, in order to obtain an air flow rate suitable for this combustion amount Q,
The rotation speed of the burner motor (BM), which controls the rotation speed of the burner motor (BM), is detected by a rotation speed detector (20), and the rotation speed signal is input to the combustion amount control means (12). The combustion amount control means (12) corrects the rotation speed control signal to the burner motor (BM) based on this rotation speed signal, and at the same time adjusts the rotation speed control signal so that the amount of oil sent is commensurate with the amount of air blown by the burner fan (not shown). The frequency of the combustion pump (5) (magnetic pump) is controlled approximately proportionally to increase or decrease the amount of combustion air and the amount of fuel oil supplied depending on the load. In this case, the air-fuel ratio is kept approximately constant, and combustion is performed at an amount commensurate with the load.

In addition, the rotation speed of the blower motor (FM) changes according to the amount of combustion.
4, and the temperature of the air discharged from the hot air outlet (10) is adjusted appropriately according to the amount of combustion.

As shown in FIG. 3, the air-fuel ratio correction means (13) calculates a fuel supply amount characteristic line for the combustion amount (air blowing i) Q determined according to the load based on the signal from the pressure detector (19). This is for parallel movement up and down. That is,
When using the heater in a place where the absolute amount of air is small, such as at a high altitude, or when using it on a day when the pressure of outdoor air is low, move the characteristic line downward like Ll. , -, the frequency of the fuel pump (5) becomes lower than normal, and an amount of fuel commensurate with the actual amount of supplied air is delivered to the burner (
2). Therefore, red flame combustion due to lack of air can be prevented. On the other hand, when the heater is used at a low altitude or on a day when the pressure of outdoor air is high, the characteristic line is translated upward as shown by L2. At this time, the pump frequency is increased to prevent excessive air flow and prevent lifting combustion. Since such air-fuel ratio adjustment is performed regardless of the magnitude of the combustion amount Q, the burner (2) always performs combustion at the optimum air-fuel ratio over the entire combustion range, and the C concentration in the exhaust gas remains approximately constant. Stable gasification and combustion can be expected.

In addition, the air-fuel ratio correction means (13) is moved not in parallel but in such a way that the gradient changes based on the signal from the pressure detector (19) (see characteristic lines L3 and L4 shown in FIG. 3).
It may be configured to perform the following.

(G) Effects of the invention Since this invention is configured as described above, the combustion amount is controlled according to the load, and the combustion amount in the burner is increased or decreased while keeping the air-fuel ratio approximately constant, and the combustion amount is adjusted to match the load. In combustion equipment, the air flow and fuel supply amount can be corrected over the entire combustion range according to changes in the absolute amount of air due to atmospheric pressure, so that combustion is always performed at the optimal air-fuel ratio, and the exhaust gas is It is possible to realize stable combustion in which the CO8 concentration of the fuel is approximately constant.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a combustion control device for a heater showing an embodiment of the present invention, Fig. 2 is a characteristic diagram showing the relationship between load and combustion amount, and Fig. 3 is a diagram showing the relationship between combustion amount and fuel supply amount. A characteristic diagram showing the relationship, FIG. 4, is a schematic configuration explanatory diagram of the heater. (11)...Microcomputer, (12)...
- Combustion amount control means, (13)...Air-fuel ratio correction means (
(adjustment means), (19)...pressure detector.

Claims (1)

[Claims] (1) In a combustion control device that controls the amount of air blown and the amount of fuel supplied according to the characteristics of the amount of air blown and the amount of fuel supplied that are predetermined so that the air-fuel ratio is approximately constant, a detector that detects atmospheric pressure is used. A combustion control device comprising: an adjustment means for changing the characteristic according to the atmospheric pressure detected by the detector.