JP2755451B2 - Combustion heater control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a control device of a combustion type heater for assisting a heating capacity of an air conditioner for an automobile, after a so-called ignition error occurs. The present invention relates to a control device for a combustion-type heater that can increase the air-fuel ratio by a predetermined amount and perform appropriate combustion when re-ignited.

(Prior Art) In general, vehicles are equipped with an air conditioner for heating the interior of a vehicle. For example, in a vehicle having a relatively large interior volume such as a microbus or a one-box car, the room temperature is reduced when the outside air is at a low temperature. In some cases, a problem arises due to insufficient heating capacity of the air conditioner, such as taking a long time to raise.

Therefore, conventionally, there is a vehicle provided with a heating auxiliary device called a combustion type heater for burning the fuel such as light oil to forcibly heat the engine cooling water and assist the heating capability of the air conditioner. . Such a combustion type heater is disclosed in Japanese Utility Model Laid-Open No. 57-128506 and the like. Conventionally, there is, for example, one shown in FIG.

The combustion type heater 1 shown in the figure is connected in series to a heater core of an air conditioner in a cooling system of an engine, and heats cooling water flowing into the heater core.

The combustion heater 1 is supplied from a fuel tank (not shown) to a vaporization mat 3 by a fuel pump 2, and the fuel vaporized by the fuel is mixed with combustion air supplied by a blower 4 in a combustion chamber 5. Is ignited by the glow plug 6 and is continuously burned in the combustion chamber 5.

And the combustion gas formed by this is the combustion cylinder 7
At the end of the combustion tube 7, passes between the outer wall of the combustion tube 7 and the heat transfer tube 8, and is discharged to the outside from the exhaust port 9.

On the other hand, the engine cooling water heated by the combustion type heater 1 is guided by a water pump 10 to a passage 12 between the inner wall of the outer cylinder 11 and the outer wall of the heat transfer tube 8,
While being heated by the heater, it is guided from the outlet 13 into the heater core. Thus, the heater core into which the heated cooling water flows performs heat exchange between the air supplied into the vehicle interior and the cooling water, thereby sufficiently heating the vehicle interior.

Various sensors for controlling combustion are provided in each part of the combustion type heater 1, and these are connected to a control device 20 for controlling the combustion type heater 1.

As shown in the figure, the combustion type heater 1 includes a frame sensor 21 for detecting a temperature in the combustion chamber 5, a water temperature sensor 22 for detecting a temperature of cooling water, and an overheat sensor 23 for detecting a surface temperature of the heat transfer tube 8, respectively. Various types of temperature information detected by these sensors are input to the control device 20.

The control device 20 is adapted to input the ON / OFF state of the manual switch 24 which is turned on by the occupant when operating the combustion type heater 1. When this is turned on, the control device 20 outputs signals from those sensors. Based on the temperature information, for example, as shown in FIG. 5, the fuel pump 2, the blower 4, the glow plug 6, and the water pump 10 are controlled to
The combustion is controlled so that the temperature of the cooling water heated by the heater falls within a predetermined temperature range.

Furthermore, since such a combustion type heater 1 is used when the outside air is at a relatively low temperature, it is started in a state where the temperature of the combustion chamber 5 and the temperature of the combustion tube 7 are at a low temperature. Ignition is not always ensured at startup. Therefore, the conventional control device 20 controls the glow plug 6 and the fuel so as to automatically re-ignite, as shown in FIG. Some are designed to control the pump 2.

As shown in the figure, the control device 20 operates when the manual switch 24 is turned on.
Then, a predetermined voltage is first applied to the glow plug 6,
This is preheated. When the time required for the glow plug 6 to be heated to the temperature required for ignition has elapsed, the fuel pump 2 is operated to supply the fuel vaporized by the vaporization mat 3 into the combustion chamber 5. At this time, the control device
20 also activates the blower 4 to supply air into the combustion chamber 5 as well as vaporized fuel.

As shown in the figure, the control device 20 controls the frame sensor while a predetermined time (90 seconds in the figure) elapses in this state.
If the temperature in the combustion chamber 5 has not risen to a predetermined temperature or more due to 21, that is, if ignition has not occurred and combustion has not been started, power supply to the glow plug 6 and the fuel pump 2 is stopped once, These operations are stopped. Thereafter, only the blower 4 is operated for a predetermined time (about 80 seconds), and after scavenging the inside of the combustion chamber 5, the fuel pump 2, the blower 4 and the glow plug 6 are similarly operated again to reignite. I have.

(Problems to be Solved by the Invention) However, in such a conventional combustion type heater, if the combustion is started by automatically re-igniting as described above, incomplete combustion is performed for a while after the ignition. May occur. This is because the fuel adhering to the inner wall surface of the low-temperature combustion cylinder due to the first ignition mistake may not be removed even if scavenging is performed. This is because the amount of generated fuel increases and the air-fuel ratio in the combustion chamber 5 temporarily decreases. As a result, there is a problem that proper combustion is not performed until such extra fuel is burned after re-ignition.

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem. In the case of re-ignition after an ignition error has occurred, the air-fuel ratio of air and fuel supplied to the combustion chamber is determined. It is an object of the present invention to provide a control device for a combustion-type heater that can perform a proper combustion by increasing a fixed amount.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a combustion chamber for burning fuel, and heat generated from the combustion chamber is applied to a heater core of an air conditioner for an automobile. A control device for a combustion type heater for heating the incoming engine cooling water before inflow and assisting the heating capacity of the automotive air conditioner, wherein a start signal output means for outputting a start signal for starting the combustion type heater, Combustion start detection means for detecting a combustion start state in which combustion starts in the combustion chamber, and the combustion start detection means, even if a predetermined time has passed even though the start signal has been output from the start signal output means, Storage means for storing a combustion start error state in which a combustion start state is not detected; and the storage means for storing the combustion start error state after the combustion start error state is stored in the storage means. When the start detecting means detects the combustion start state, and having an air-fuel ratio control means for increasing a predetermined amount the air-fuel ratio of air and fuel supplied to the combustion chamber.

(Operation) The present invention configured as described above operates as follows.

A start signal is output from the start signal output means, and even if the combustion heater starts, the combustion start detection means does not detect the combustion start state even after the lapse of a predetermined time. If not, the storage means stores the state of misfiring, that is, the occurrence of misfiring. After that, when the combustion start detecting means detects the combustion start state, that is, when re-ignition is performed, the air-fuel ratio control means reduces the fuel by a predetermined amount or increases the air by a predetermined amount, The air-fuel ratio between air and fuel supplied to the combustion chamber is increased by a predetermined amount. As a result, when a misfire occurs at the time of starting and reignition occurs, air that can completely burn the fuel remaining in the combustion chamber and the newly supplied fuel due to the misfire is supplied into the combustion chamber. That means
Appropriate combustion can be performed.

(Embodiment) Hereinafter, a combustion heater control device according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic configuration diagram of a control device of a combustion heater according to the present invention, and FIG. 2 is an operation flowchart of the control device. FIG. 3 shows an operation flowchart of the control device as another embodiment. In these drawings, the same members as those described in the related art are denoted by the same reference numerals. Further, the configuration of the combustion type heater is the same as that of the conventional heater, so that the detailed description thereof is omitted here.

As shown in FIG. 1, a flame sensor 21 as a combustion start detecting means for detecting a temperature in a combustion chamber 5 of the combustion type heater 1 (hereinafter referred to as a combustion chamber temperature) controls the detected combustion chamber temperature. The data is output to the unit 30.

When the occupant is turned on when the combustion type heater 1 is started, the manual switch 24 as a start signal output means is turned on, and similarly outputs a start signal to the control unit 30 to start the combustion type heater 1. It has become.

Then, the control unit 30 operates the fuel pump 2, the blower 4, and the glow plug 6 based on the start signal and the temperature in the combustion chamber. This control unit
Numeral 30 is provided in the control device 20 described in the related art, and the control device 20 controls the combustion heater 1 in the same manner as in the related art, except for the ignition and re-ignition control described below. Has become.

Furthermore, the blower 4 can increase or decrease the amount of air supplied into the combustion chamber 5 according to the voltage output by the control unit 30. When the control unit 30 increases the voltage, The air amount is increased by the increased amount.

The control unit 30 has a memory 31 for storing that an ignition error has occurred, and a control unit 30 for determining whether an ignition error has occurred and for controlling a time for increasing the air-fuel ratio. Timer 32 to measure the time required to perform
And are connected respectively.

Then, similarly to the related art, the control unit 30 automatically re-ignites when an ignition error occurs at the time of starting,
The fuel pump 2, the blower 4 and the glow plug 6 are operated. If the fuel does not ignite by this operation, it is determined that the fuel pump 2, the blower 4 and the glow plug 6 are abnormal. The power supply is stopped, these operations are stopped, and the combustion type heater 1 is not operated.

Further, when re-ignition occurs, the control unit 30
Is increased by a predetermined amount, and the amount of air supplied into the combustion chamber 5 by the blower 4 is increased by a predetermined amount. That is, when the control unit 30 reignites,
By increasing the amount of combustion air by a predetermined amount, the air-fuel ratio between the fuel and the air supplied into the combustion chamber 5 is increased by a predetermined amount, and the fuel remaining in the combustion chamber 5 due to an ignition mistake,
Completely burn the newly supplied fuel.

With such a configuration, the control device of the present invention operates based on the operation flowchart shown in FIG.

First, upon input of a start signal from the manual switch 24, the control unit 30 assigns 1 to a flag n in the memory 31 to store the first ignition operation (step 1), The glow plug 6 is preheated by applying a predetermined voltage to heat it (step 2).

Then, the control unit 30 waits until a preheating time (preset in the timer 32) in which the glow plug 6 is heated to a temperature required for ignition elapses (step 3), and when the preheating time elapses. Then, the fuel pump 2 and the blower 4 are operated to supply fuel and air into the combustion chamber 5 to start combustion (step 4).

Then, the control unit 30 inputs the temperature of the combustion chamber output by the flame sensor 21, and within a predetermined time (90 seconds after the start of the fuel pump), the temperature becomes equal to or higher than a predetermined temperature corresponding to a combustion start state in which combustion has started. By determining whether or not ignition has occurred, it is determined whether or not ignition has been performed (step 5,
6).

Then, when the control unit 30 determines that the combustion chamber temperature input from the frame sensor 21 has not become equal to or higher than the predetermined temperature within the predetermined time in steps 5 and 6, and has not ignited,
In preparation for the next ignition operation, the operation of the fuel pump 2 is stopped (step 7), and only the blower 4 is operated for the scavenging time necessary for scavenging (preset in the timer 32) to allow the inside of the combustion chamber 5 to be operated. After the air is purged, the operation of the blower 4 is stopped (steps 8 and 9).

Further, the control unit 30 adds 1 to the flag n of the memory 31 to store that the ignition error has occurred (step 1).
0), the flow returns to step 1 until the flag n becomes 3, and an operation for re-ignition is performed (step 11). When the flag n becomes 3, that is, when the ignition is not performed despite the re-ignition operation, the process is terminated.

Then, when the control unit 30 determines that the temperature in the combustion chamber input from the frame sensor 21 has become equal to or higher than the predetermined temperature within the predetermined time in Steps 5 and 6 by the first ignition operation or the re-ignition operation, It is determined whether or not the flag n is 2, and if the flag n is not 2, that is, if the flag n is 1 and the ignition is performed in the first ignition operation, the flag n is reset, and the process proceeds to step 16, where The process proceeds to the normal heating control mode shown in FIG. 5, and the combustion is controlled so that the water temperature falls within a predetermined temperature range (step 12).

On the other hand, when the flag n is 2 and the ignition is performed by the re-ignition operation, the control unit 30 performs the predetermined time (from the re-ignition) to completely burn the surplus fuel remaining in the combustion chamber 5 due to the ignition mistake. Until the elapse of about 30 seconds, the voltage supplied to the blower 4 is increased by a predetermined amount, and the air that is increased by a predetermined amount from the air amount necessary for normal combustion is supplied into the combustion chamber 5 (steps 13 and 14). . At this time, a voltage for supplying fuel necessary for normal combustion is applied to the fuel pump 2, whereby the air-fuel ratio of air and fuel supplied into the combustion chamber 5 increases by a predetermined amount. The surplus fuel remaining in the combustion chamber 5 due to an ignition mistake is appropriately burned by the increased air, and complete combustion is performed in the combustion chamber 5.

Then, when the control unit 30 determines that a predetermined time has elapsed since the ignition and that the fuel remaining due to the ignition mistake has been completely burned by the increased air, the voltage applied to the blower 4 is set to the normal combustion voltage. The amount of air supplied to the combustion chamber 5 is set to the amount of air necessary for normal combustion, the flag n is reset, the mode shifts to the normal heating control mode, and the combustion is controlled so that the water temperature falls within a predetermined temperature range (step). 15,16).

Accordingly, the control unit 30 receives the start signal, performs the ignition operation, and performs the ignition operation again.If the ignition is not performed, the control unit 30 performs the ignition operation again. Since the amount of air supplied into the combustion chamber 5 is increased by a predetermined amount in order to completely burn the fuel remaining in the combustion chamber 5 due to the first ignition mistake, after re-ignition, the remaining fuel finishes burning. The combustion state in the combustion chamber 5 up to the above becomes good. This prevents incomplete combustion after re-ignition.

In addition to the above embodiment, as shown in FIG. 3, the fuel supplied into the combustion chamber 5 after re-ignition may be reduced by a predetermined amount, and the air-fuel ratio after re-ignition may be increased by a predetermined amount. In this case, the control unit 30 decreases the voltage supplied to the fuel pump 2 by a predetermined amount so that the fuel discharge amount of the fuel pump 2 is reduced by a predetermined amount. Steps 20 to 30 shown in FIG. 8 are the same as the operations for performing the first ignition and re-ignition of steps 1 to 11 shown in FIG. 2, and thus the description thereof is omitted here.

As shown in the figure, the control unit 30 performs the first ignition operation or the re-ignition operation, and in steps 24 and 25, the temperature in the combustion chamber input from the frame sensor 21 becomes equal to or higher than the predetermined temperature within a predetermined time, and the control unit 30 ignites. If the flag n is 2, it is determined whether or not the flag n is 2, and if the flag n is not 2, that is, if the flag n is 1, and the ignition is performed in the first ignition operation, the flag n is reset and step 35 is performed. The process proceeds to the normal heating control mode shown in FIG. 5 in the same manner as in the above embodiment, and the combustion is controlled so that the water temperature falls within a predetermined temperature range (step 31).

On the other hand, when the flag n is 2 and the ignition is performed by the re-ignition operation, the control unit 30 completely burns the residual fuel remaining due to the ignition mistake in the combustion chamber 5 with air necessary for normal combustion. At a predetermined time (approximately 30
Until the elapse of (second), the voltage supplied to the fuel pump 2 is reduced by a predetermined amount, and the fuel that is reduced by a predetermined amount from the fuel amount necessary for normal combustion is supplied into the combustion chamber 5 (step 3).
2,33). At this time, a voltage for supplying air required for normal combustion is applied to the blower 4, whereby the air-fuel ratio of air and fuel supplied into the combustion chamber 5 increases by a predetermined amount. That is, by reducing the fuel supplied into the combustion chamber 5 by the amount of the residual fuel, the fuel in the combustion chamber 5 containing the residual fuel is appropriately burned by the air necessary for normal combustion, and Burning takes place.

When the control unit 30 determines that a predetermined time has elapsed after the ignition and that the remaining fuel has been completely burned due to an ignition mistake, the control unit 30 sets the voltage applied to the fuel pump 2 to the normal combustion voltage, and sets the voltage to the combustion chamber. The amount of fuel supplied into the fuel tank 5 is set to an amount necessary for normal combustion, the flag n is reset to shift to a normal heating control mode, and the combustion is controlled so that the water temperature falls within a predetermined temperature range (steps 34 and 35). ).

Therefore, even in this case, similarly to the above-described embodiment,
The combustion state in the combustion chamber 5 after re-ignition can be improved.

In each of the above embodiments, in steps 14 and 33, the air amount increased by a predetermined amount and the fuel amount decreased by a predetermined amount are used to determine the air amount required for normal combustion based on the elapsed time after re-ignition. The amount and the amount of fuel are returned to each other, and it is determined from the elapsed time that the remaining fuel due to an ignition mistake has been burned.However, the present invention is not limited to this.For example, the combustion chamber detected by the frame sensor 21 may be used. When the combustion becomes stable based on the temperature in the combustion chamber 5, the light of the flame in the combustion chamber 5 is detected by a light-receiving element such as a photodiode, and the amount of the light becomes a predetermined amount or more, and the combustion state is reduced. Needless to say, the air amount and the fuel amount may be returned to the normal state based on a stable case.

Similarly, a flame sensor as combustion start detecting means
Of course, 21 may be a light receiving element such as the above-mentioned photodiode.

Furthermore, the manual switch 24 has been described as an example for outputting an operation signal for operating the combustion type heater 1, but the present invention is not limited to this. For example, a timer for operating the combustion type heater at a set time may be used. Of course.

(Effects of the Invention) As apparent from the above description, the present invention has the following effects.

A start signal is output from the start signal output means, and even if the combustion heater starts, the combustion start detection means does not detect the combustion start state even after the lapse of a predetermined time. If not, it is stored in the storage means that the combustion start error state, that is, the occurrence of the ignition error, and thereafter, when the combustion start detection means detects the combustion start state, that is, when the ignition is performed again The air-fuel ratio control means reduces the fuel by a predetermined amount or increases the air by a predetermined amount to increase the air-fuel ratio of the air and fuel supplied into the combustion chamber by a predetermined amount. Occurs, and when re-ignition occurs, air capable of completely burning the fuel remaining in the combustion chamber due to an ignition mistake and the newly supplied fuel is supplied into the combustion chamber. Becomes bets, it is possible to perform a proper combustion.

Therefore, when re-ignition occurs after an ignition error, complete combustion can be performed by increasing the air-fuel ratio by a predetermined amount.

Further, among the above, if the air supplied to the combustion chamber is increased by a predetermined amount so as to increase the air-fuel ratio, the fuel remaining in the combustion chamber due to an ignition mistake and the newly supplied fuel will increase the amount of air. The fuel burns, and the calorific value after re-ignition is larger than the calorific value after normal ignition, and the engine cooling water flowing into the heater core can be heated more quickly. It also has the effect of being able to heat up.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a combustion heater control device according to the present invention, FIG. 2 is an operation flowchart of the control device, and FIG. 3 is a combustion heater control device according to the present invention as another embodiment. FIG. 4 to FIG. 6 are explanatory diagrams of a conventional control device for a combustion type heater. DESCRIPTION OF SYMBOLS 1 ... Combustion heater, 2 ... Fuel pump (air-fuel ratio control means), 4 ... Blower (air-fuel ratio control means), 6 ... Glow plug, 21 ... Flame sensor (combustion start detection means), 24 ... Manual switch (start signal) Output means), 30 ... control unit (air-fuel ratio control means), 31 ... memory (storage means), 32 ... timer (air-fuel ratio control means).

Claims (1)

(57) [Claims] A combustion chamber (5) for burning fuel is provided, and heat generated from the combustion chamber (5) heats engine cooling water flowing into a heater core of an air conditioner for a vehicle before flowing into the combustion chamber, thereby providing a fuel for a vehicle. A control device for a combustion type heater (1) for assisting a heating capacity of an air conditioner, a start signal output means (24) for outputting a start signal for starting the combustion type heater (1), and the combustion chamber (5). Combustion start detection means (21) for detecting a combustion start state in which combustion starts, and the combustion is started even after a predetermined time has passed even though the start signal is output from the start signal output means (24). A storage means (31) for storing a combustion start error state in which the start detection means (21) does not detect the combustion start state, and the combustion start error state is stored in the storage means (31). Later, the combustion open Air-fuel ratio control means (2, 4, 30, 32) for increasing the air-fuel ratio between air and fuel supplied to the combustion chamber (5) by a predetermined amount when the detection means (21) detects the combustion start state And a control device for a combustion type heater.