JPH04978Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention relates to a combustion type heater for automobiles that uses kerosene, diesel oil, or gasoline as fuel, and in particular prevents carbon from adhering to the plug used for igniting the fuel. It was designed to do so.

(Prior art) In relatively large vehicles such as microbuses, where the interior volume is large, or where the engine water temperature is low, in order to heat the interior of the vehicle, it is necessary to As shown in the -194362 publication, a combustion type heater is provided. Such a combustion type heater for an automobile has a combustor attached to a heat exchanger for supplying hot air into the vehicle interior, and a fuel injector such as a fuel discharge nozzle or a fuel vaporization plate provided on the combustor. A fuel pump is connected to supply fuel. Furthermore, in order to ignite the fuel and preheat or vaporize the fuel, a plug is installed inside the combustor, and an air pump is connected to the combustor to supply air for combustion. ing.

Conventionally, such combustion heaters for automobiles are
The fuel pump, plug, and air pump are controlled as shown in the figure. As shown in Figure 7, the main switch for operating the combustion heater
When the SW is turned on, the plug PL is energized and the air pump AP operates for a short time. This short-term operation of the air pump AP is called pre-purge, and it cleans the air inside the combustor.
Then, after a predetermined time, the air pump AP starts operating, and the fuel pump FP is turned on, and fuel is discharged from the nozzle into the combustion chamber. In this way, when the fuel is discharged, the fuel is ignited by the plug PL to start combustion, and after ignition is completed, the power supply to the plug PL is stopped. As the fuel from the fuel pump FP is burned in the combustor, warm air is supplied into the vehicle interior.

Conventionally, when the combustion heater is stopped by stopping the engine or the passenger operates the main switch, the fuel pump FP
Then, the air pump AP stops, and the blowing of warm air into the passenger compartment is completed.

(Problem to be solved by the invention) In such combustion type heaters, carbon tends to adhere to the plug PL during combustion or when unburned gas is discharged at the end of combustion. Efforts have been made to continue operating the air pump AP even after the FP has been stopped to perform a so-called after-purge, and to install an air intake port near the plug, but these efforts have not been able to sufficiently remove unburned carbon. There may be no. If unburned carbon cannot be removed, there is a problem in that ignition errors and plug shorts may occur.

In view of the problems of the prior art described above, the present invention aims to prevent unburned carbon from adhering to the plug in a combustion type heater for an automobile.

(Means for Solving the Problems) The present invention for achieving the above object includes a combustor incorporated in a heat exchanger, and a fuel pump that supplies fuel to a fuel injector attached to the combustor. ,
In the combustion type heater for an automobile having an ignition plug attached to the combustor and an air pump supplying combustion air into a combustion chamber of the combustor, the combustion type heater stops operating by a main switch. A combustion type heater for an automobile, comprising an ignition control means for igniting the plug in response to a signal, and an air pump operation control means for operating the air pump within a predetermined time while the main switch is igniting the plug. It is.

(Example) The present invention will be described below with reference to an illustrative example. FIG. 1 is a sectional view showing the schematic structure of the combustion type heater for an automobile according to the present invention. A heat exchanger 1 installed in a vehicle heats liquid that flows in from an inlet 2 formed in the heat exchanger 1 and reaches an outlet 3. Therefore, the combustion chamber 4
A combustor 5 is installed. In the illustrated embodiment, the liquid discharged from the outlet is guided to a heater core (not shown) to heat the interior of the vehicle, but air is supplied to the inlet 2 and the high temperature air is may be directly discharged into the vehicle interior. A nozzle 6 as a combustion injector for discharging fuel into the combustor 4 is attached to the combustor 5, and the nozzle 6 is connected to a fuel pump FP. A plug PL is attached to the combustor 5 to ignite the fuel and preheat or vaporize the fuel, and an air pump AP is connected to the combustor 5 for supplying combustion air into the combustor 4. ing. In addition to the method using the nozzle 6, it is also possible to use a fuel vaporization plate as the fuel injector. The fuel vaporization plate is made of non-combustible material such as asbestos, and the fuel is sent from the fuel pump FP and permeates there, and the fuel is vaporized by heating by the plug PL and the heat of the fuel, and connects ignition and combustion. It is.

The operation start and stop of the combustion heater configured as described above is controlled by the main switch installed on the vehicle.
Done by SW. The operation of the main switch SW activates the controller 11, which controls the operation of the plug PL, etc., but this controller 11 receives a signal indicating that the main switch SW is turned off and stops the fuel pump FP. In addition, an ignition control means 12 that ignites the plug PL for a predetermined period of time, and an air pump operation control means 13 that operates the air pump AP only while the plug PL is ignited based on a signal from the ignition control means 12 are electrically controlled. It is connected.

An example of a specific configuration of the ignition control means 12 and the air pump operation control means 13 is shown in FIG. 2. Main switch as shown
A relay 20 is connected in series to the SW, and in order to release the power to the fuel pump FP by operating the relay 20 when the main switch SW is turned off, the relay 20 is connected in series to the fuel pump FP. A relay 21 is connected to.

In addition, when the main switch SW is turned off, the plug PL is turned off to energize the plug PL.
A relay 22 is connected between the power supplies. Then, when the main switch SW is turned off, relay 2
By 0, relay 21, 22 and relay 23 at the same time
is also turned on, and timer TR starts operating.
When the predetermined time set in the timer TR has elapsed, the normally closed switch 24 activated by the timer TR and connected to the plug PL turns off, and
Normally closed switch 25 connected to air pump AP
is turned off. Relays 26 and 27 are provided to prevent plug PL and timer TR from operating while fuel pump FP is operating.

Next, the action will be explained with reference to Figure 3.
When the passenger turns off the main switch SW to stop the combustion heater, the relay 21 shown in FIG. 2 in the ignition control means 12 turns off, and the relay 22 turns on, so the fuel pump FP
stops, and energization to the plug PL starts. At the same time, the timer TR starts operating, and when the time T set in the timer TR has elapsed, the air pump AP stops operating, and
Power to the plug PL is stopped. Since the plug PL is ignited when the fuel supply is stopped, even if there is unburned carbon attached to the plug PL, the unburned carbon will be burned and the air pump
It will be discharged to the outside by the air blown by the AP. Therefore, adhesion of carbon to the plug PL is prevented, and problems caused by adhesion of carbon are prevented.

FIG. 4 is a time chart showing the control of the combustion type heater according to another embodiment of the present invention, in which the plug PL is ignited for a predetermined time T upon receiving a signal from the main switch SW that the combustion type heater has stopped operating. At the same time, when the plug PL is ignited, the operation of the air pump AP is stopped for a predetermined time T1, and then the air pump AP is started for a predetermined time T2. In this case the plug
Since the air pump AP is operated after the PL is sufficiently heated, the attached carbon is more easily combusted than in the previous embodiment.

FIG. 5 is a time chart showing the control of a combustion type heater according to another embodiment of the present invention. In this case, in response to the off signal from the main switch SW,
The PL is ignited for a predetermined time T, and after a predetermined time T3 has elapsed, the air pump AP is activated, and then the air pump AP is activated for a predetermined time T4.
The operation of the air pump AP is stopped, and the air pump AP is further operated for a predetermined time T5. As a result, since the air pump AP is operated for a predetermined time T3, after-purging is performed and unburned gas in the combustion chamber 4 is discharged to the outside. Abnormal combustion can also be prevented.

FIG. 6 is a time chart showing control of a combustion type heater according to another embodiment of the present invention, showing a case in which afterpurge is performed for a predetermined time T5, similar to the case shown in FIG.

In this case, the plug PL is ignited after a predetermined time T5 has elapsed after receiving the off signal from the main switch SW, and the air pump AP continues to operate during this predetermined time T5. . Simultaneously with the ignition of the plug PL, the operation of the air pump AP is stopped for a predetermined time T6, and then the air pump AP is started for a time T7. In this way, since the unburned gas in the combustion chamber 4 is discharged by the air pump AP before igniting the plug PL, it is possible to reliably prevent abnormal combustion due to the unburned gas.

(Effects of the invention) As described above, according to the invention, since the glow plug is ignited after the combustion heater stops, even if unburned carbon adheres to the glow plug,
It becomes possible to reliably burn and remove this.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a schematic structure of a combustion type heater according to an embodiment of the present invention, FIG. 2 is a circuit diagram showing a specific structure of an air pump operation control means of an ignition control means, and FIG. Time chart No. 4 showing the control process of the combustion type heater of the present invention shown in Figures 1 and 2.
6 are time charts showing the control process of a combustion type heater according to another embodiment of the present invention, and FIG. 7 is a time chart showing the control process of a conventional combustion type heater. 5... Combustor, 6... Nozzle, 12... Ignition control means, 13... Air pump operation control means,
AP...Air pump, PL...Plug, FP...
Fuel pump, SW...main switch.

Claims (1)

[Scope of utility model registration request] A combustor incorporated in a heat exchanger, a fuel pump that supplies fuel to a fuel injector attached to the combustor, an ignition plug attached to the combustor, and a combustion chamber of the combustor. An ignition control means for igniting the plug in response to a signal from a main switch indicating that the combustion heater has stopped operating; and air pump operation control means for operating the air pump within a predetermined time period while the air pump is ignited.