JP3212424B2 - Blower motor control circuit for combustion of combustor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion blower motor control circuit for supplying combustion air to a combustor such as a heating device.

[0002]

2. Description of the Related Art A conventional combustion blower motor in a heating device controls a fuel supply pump and a combustion blower independently from each other by a microcomputer or the like. Then, the amount of air to be blown is set without considering a change in air density due to a change in outside air temperature.

[0003]

In order to perform proper combustion, it is necessary to always maintain an appropriate air-fuel ratio. If the air-fuel ratio is inappropriate, incomplete combustion occurs. The required amount of air is affected by the density of the blown air.

It is an object of the present invention to provide a combustion blower motor control circuit for a combustor in which the air-fuel ratio is always kept properly by simple control taking into account the density of the blown air.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a combustion fan motor control circuit for a combustion fan, in which combustion air is supplied and burned by a combustion fan. A motor rotation control element that controls the rotation speed, an outside air temperature detection circuit that detects an outside air temperature, and a plurality of outside air temperatures that are set based on the air density at a predetermined reference outside air temperature and based on the reciprocal of the air density. A rotation correction coefficient storage unit that stores a rotation correction coefficient of the combustion blower motor composed of each air density correction coefficient, and one or more rotation correction coefficients corresponding to the high temperature side and the low temperature side with respect to the reference outside air temperature, respectively. A control condition selecting means that allows the level of the rotation correction coefficient to be selectable in advance, and detection data of the outside air temperature detection circuit being higher or lower than the reference outside air temperature. Address means for reading a rotation correction coefficient corresponding to a high-temperature area or a low-temperature area of the level from the rotation correction coefficient storage unit by an address code based on the determination as to whether or not and the respective selection data by the control condition selection means; A motor rotation control circuit for controlling the motor rotation control element based on the rotation correction coefficient read from the rotation correction coefficient storage unit.

[0006]

According to the present invention, the reference outside air temperature is set, and the control condition selection means selects and specifies the reference outside air temperature, the rotation correction coefficient on the high temperature side, and the rotation correction coefficient on the low temperature side in advance. From the rotation correction coefficient storage unit, based on each selection data by the control condition selection means and an address code based on whether the detection data of the outside air temperature detection circuit is higher or lower than the reference outside air temperature. The rotation correction coefficient corresponding to the side or the low temperature side is read, and the motor rotation control element is controlled based on the read rotation correction coefficient.

[0007]

FIG. 1 is a circuit diagram of a combustion blower motor control circuit for a combustor according to an embodiment of the present invention.

In FIG. 1, M is a combustion blower motor composed of a DC motor with a commutation brush, which coaxially drives a combustion blower (not shown) for supplying combustion air. E is a DC power supply for driving the motor, Q is a transistor as a motor rotation control element, and transistor Q is a blower motor M for combustion.
The terminal voltage is controlled to control the rotation speed. D
V is a drive control circuit that drives and controls the combustion blower motor M. The drive control circuit V supplies the base voltage of the transistor Q according to the drive designation and controls the rotation of the combustion blower motor M. Th
Is an outside air temperature detector for detecting the outside air temperature, AD is an A / D converter for A / D converting the detected outside air temperature t, and VCC is a control power supply for the switch SW.

The ROM is a rotation correction coefficient storage unit. In this embodiment, the reference outside air temperature T is set to 0 ° C., and the rotation correction coefficient K of the combustion fan motor M is stored in the ROM. That is, based on the air density at 0 ° C.
1.00 is stored as the rotation correction coefficient K, which is an air density correction coefficient for each of the plurality of outside air temperatures t set based on the reciprocal of the air density. FIG. 2 is a diagram showing a rotation correction coefficient K for each outside air temperature t.

SW is a DIP type switch as a control condition selecting means. Before the shipment of the combustor, an external air temperature t of 0 ° C. ± 5 ° C., ie, +5
In the range of -5 ° C to -5 ° C, it is specified that 1.00 can be read as the reference rotation correction coefficient K0, and 1.04 or 1.08 can be read as the high-temperature side rotation correction coefficient KU corresponding to the temperature higher than + 5 ° C. And -5 ° C
In order to correspond to the case where the temperature is on the lower temperature side, 0.97 or 0.93 is designated to be readable as the low temperature side rotation correction coefficient KL. R is a pull-down resistor. DI is a discrimination circuit serving as an address means for the rotation correction coefficient storage unit ROM, which receives an outside air temperature t and an operation signal of the switch SW,
It is determined whether the outside air temperature t is in the range of + 5 ° C. to −5 ° C., or higher than + 5 ° C. or lower than −5 ° C., and the reference rotation correction coefficient K0 or the rotation correction coefficient KU on the high temperature side or An address signal is output to the rotation correction coefficient storage unit ROM in order to designate the low temperature side rotation correction coefficient KL as readable.

The drive control circuit DV controls the combustion blower motor M to a required reference rotation for the reference rotation correction coefficient K0 = 1.00, and a rotation correction coefficient storage unit RO
The rotation correction coefficient K0 or KU or K output from M
Based on L, the reference rotation is corrected and controlled.

In the above configuration, prior to shipment of the combustor, the reference outside air temperature T is set to 0 ° C., the reference rotation correction coefficient K0 is 1.00, and the high-speed rotation correction coefficient KU and the low-temperature It is assumed that the side rotation correction coefficient KL is specified.

When the combustion blower motor M is started by the drive control circuit DV, the outside air temperature t is detected by the outside air temperature detector Th, and the discrimination circuit DI discriminates the outside air temperature t and determines the reference rotation correction coefficient K0 or The rotation correction coefficient KU on the high temperature side or the rotation correction coefficient KL on the low temperature side is output. The drive control circuit DV controls the rotation of the combustion blower motor M based on the reference rotation correction coefficient K0 or the rotation correction coefficient KU or KL output from the rotation correction coefficient storage section ROM, at a required reference rotation at the reference outside air temperature T. Is corrected and controlled. As a result, the change in the air density due to the change in the outside air temperature t is compensated, and the air-fuel ratio is appropriately maintained.

Although not shown in the present embodiment, in the ignition stroke from ignition to normal combustion, generally, the combustion blower motor M is operated so that the amount of air blown for combustion is larger than that during normal combustion. A reference rotation speed at the time of ignition is set, and the rotation of the combustion blower motor M is controlled by correcting the rotation of the combustion blower motor M with respect to the reference rotation speed at the time of ignition by using the same rotation correction coefficient in this ignition stroke. It is possible to reliably ignite without being affected by the temperature t.

[0015]

As described above, according to the present invention, the rotation of a combustion blower motor for correcting a change in air density with respect to the outside air temperature based on the air density at a predetermined reference outside air temperature is used as a reference. The coefficient is stored, and when the outside air temperature is higher than the reference outside air temperature, the high-temperature rotation correction coefficient can be read, and when the outside air temperature is low, the low-temperature rotation correction coefficient can be read. Since the rotation is controlled based on the side rotation correction coefficient or the low-temperature rotation correction coefficient, a change in air density due to a change in outside air temperature is compensated for by a simple configuration, and the air-fuel ratio is appropriately maintained.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a combustion blower motor control circuit for a combustor according to an embodiment of the present invention.

FIG. 2 is a diagram showing a rotation correction coefficient with respect to an outside air temperature;

[Explanation of symbols]

M: combustion blower motor, E: DC power supply, Q: transistor, DV: drive control circuit, Th: outside air temperature detector, R
OM: rotation correction coefficient storage unit; SW: switch; DI: discrimination circuit.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-1-263413 (JP, A) JP-A-61-15578 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F23N 3/08 F23N 5/14

Claims (1)

(57) [Claims] 1. A combustion fan motor control circuit for a combustor for supplying combustion air by a combustion blower and burning the motor, a motor rotation control element for controlling a rotation speed of the combustion fan motor, and detecting an outside air temperature. An outside air temperature detection circuit, and a rotation correction coefficient of a combustion blower motor comprising a plurality of air density correction coefficients for a plurality of outside air temperatures set based on an air density at a predetermined reference outside air temperature and based on a reciprocal of the air density. A stored rotation correction coefficient storage unit, and control condition selection means for preselecting one or more levels of the rotation correction coefficient in correspondence with the high temperature side and the low temperature side with respect to the reference outside air temperature Discriminating whether the detection data of the outside air temperature detection circuit is higher or lower than the reference outside air temperature, and selecting each data by the control condition selection means. Address means for reading a rotation correction coefficient corresponding to a high-temperature region or a low-temperature region of the level from the rotation correction coefficient storage unit using an address code based on the rotation correction coefficient read from the rotation correction coefficient storage unit; And a motor rotation control circuit for controlling the motor rotation control element based on the motor control circuit.