JPH0522127B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fuel flow path abnormality detection device for a heater that detects abnormality in a fuel flow path of a heater that heats a vehicle interior.

(Prior technology) Vehicle interior heating has traditionally used the engine's cooling water as a heat source to heat the air taken in to heat the interior of the vehicle, but in cold weather it takes time for the cooling water temperature to rise. , a proposal for a heating system for a vehicle that burns fuel in a burner separate from the engine, recovers the combustion heat in a heat exchanger, and controls the burner according to the engine condition was proposed in Japanese Patent Application Laid-Open No. 157422/1983. Disclosed.

(Problems to be Solved by the Invention) In the proposal of a heating system for a vehicle shown in the above-mentioned Japanese Patent Application Laid-open No. 157422/1983, warm air for heating can be rapidly obtained even in cold weather, but No countermeasures have been taken to detect abnormalities in the fuel flow path that supplies the fuel to the fuel vaporizer, such as clogging of the flow path with carbon due to prolonged use of the vaporizer equipped with a heater, or to remove the carbon. ,
This causes a problem in which the heating efficiency of the heating device decreases or heating becomes impossible.

The present invention has been made in view of the above problems, and its purpose is to provide a heater fuel flow path abnormality detection device for detecting clogging of the fuel flow path of a vehicle heater and taking appropriate measures. It is on offer.

(Means for Solving the Problems) In order to achieve the above object of the invention, the present invention recovers the heat generated by burning the fuel mixture in the combustion chamber with a heat exchanger, and uses the recovered heat for heating. A fuel flow path abnormality detection device for a heater used in a heater includes a storage means for storing a map comparing normal combustion temperature with respect to the amount of combustion air blown and the amount of fuel supplied, and an air volume for detecting the amount of combustion air blown. a detection means, a fuel supply amount detection means for detecting the amount of fuel supplied, a temperature detection means for detecting combustion temperature, an air volume from the detected air volume detection means and a fuel supply amount detected by the fuel supply amount detection means. a search means for searching the standard combustion temperature from the map of the former storage means using
The searched standard combustion temperature is compared with the combustion temperature detected by the temperature detection means, and when the combustion temperature is lower than the standard combustion temperature, an alarm is issued, the fuel supply is stopped, and the fuel flow path is heated by the heating means. A fuel flow path abnormality detection device for a heater is provided, comprising: a control means for burning the residue.

(Function) In the present invention, the amount of combustion air blown and the fuel flow rate are both maximized to combust the fuel, the combustion temperature in this state is checked, and the combustion temperature in the state where the fuel flow path is clogged is stored in the memory. I'll keep it. When an abnormality is detected in the fuel flow path, the air flow rate and fuel flow rate are maximized and compared with the stored combustion temperature to determine whether the abnormality is due to clogging. Furthermore, when a clogging of the fuel flow path is detected, the fuel supply is stopped and then the heater of the vaporizing glow plug is energized to incinerate and remove carbon.

(Example) Next, an example of the present invention will be described in detail using the drawings.

FIG. 1 is a block diagram showing an embodiment of the fuel flow path abnormality detection device for a heater according to the present invention. In the figure, 1 is a fuel combustor, which includes a combustion blower 11 that blows combustion air, a vaporization glow plug 12 that vaporizes the fuel, an ignition glow plug 13 that ignites the vaporized fuel, and a combustion temperature of the combustor 1 that is detected. It is equipped with a flame sensor 14 and blows high-temperature combustion gas ignited by the operation of the combustion blower 11 to the heat exchanger 2 connected downstream. The vaporizing glow plug 12 has a built-in heater having a temperature coefficient of resistance, and by measuring the voltage drop value of the resistor 12a connected in series with a minute resistance value,
It is configured to be able to detect a resistance value that changes depending on the temperature of the heater of the vaporizing glow plug 12. 1
2b is a control resistor that suppresses the current flowing to the vaporizing glow plug 12, and 12c is a changeover switch that short-circuits the control resistor 12b to release the suppression.

The ignition glow plug 13 also has a built-in heater having a temperature coefficient of resistance, and a resistor 13a with a small resistance value, a control resistor 13b, and a changeover switch 13c connected in series are connected to the power transmission circuit. It is configured to operate in the same manner as each member of the 12 power transmission circuits. The appropriate temperature for both of these glow plugs is 400℃ for the vaporizing glow plug 12 and 900℃ for the ignition glow plug.
It is heated to ℃.

4 is a fuel tank, and a fuel pump 41 and a fuel valve 42 are provided in the fuel supply path, both of which are controlled by commands from an electronic control device to be described later.

The heat exchanger 2 exchanges heat of the combustion gas blown from the combustor 1 with outside air from the air intake port 21 and blows it out from the air outlet 23 into the passenger compartment 5 by operating the hot air blower 22. A large number of heat exchange fins 24 are provided inside the heat exchanger 2. The combustion gas after heat exchange is then discharged into the atmosphere from the exhaust port 25 as exhaust gas.

A room temperature meter 51 is installed inside the vehicle compartment 5 and transmits a detected temperature signal to the electronic control device 7.

The electronic control unit 7 is composed of a microcomputer, and includes a central processing unit that performs arithmetic processing and timer processing that counts the time of a control signal (described later), a program that controls the combustor, and processes when an abnormality occurs in the fuel flow path. , various memory devices for storing information such as the combustion temperature when the fuel flow path is clogged, and input/output devices.
The signal of the resistance value corresponding to the temperature of the vaporizing glow plug 12 and the ignition glow plug 13 provided in the ignition glow plug 12 and the signal from the flame sensor 14 are input.
In addition, a heat exchanger temperature sensor 2 provided in the heat exchanger 2
6. A signal based on the temperature from the hot air sensor 27 provided at the outlet 23 is also input, and the combustion blower 1
1 and the flow rate signal of the fuel pump 41 are input.

Note that the output of the electronic control device 7 includes the fuel pump 41, the fuel valve 42, and the combustion blower 1 of the combustor 1.
1. It is configured to issue respective control commands to the changeover switches 12c and 13c, the warm air blower 22, the abnormality signal light 84, etc.

81 is an air temperature sensor that detects the temperature of the atmosphere; 82
A temperature control switch 83 sets the internal temperature of the vehicle compartment 5, and an operation switch 83 are connected to the electronic control device 7 so as to transmit signals.

FIG. 2 is a processing flow diagram showing an example of the operation of this embodiment. Next, the operation will be explained using FIG.

First, the operation switch 83 is turned on, and if the temperature signal _TR from the room temperature meter 51 provided in the vehicle compartment 5 is lower than the predetermined temperature _T1 , the resistance value of the ignition glow plug 13 is measured (steps 1 to 3). .

In step 4, in order to check the temperature of the ignition glow plug 13, the resistance value determined in step 3 is
Compare R _I with a predetermined resistance value R ₁ , and if R _I > R ₁ , proceed to step 5 and energize the ignition glow plug 13 to determine the resistance value R ₉₀₀ when the temperature of the ignition glow plug 13 is 900°C. and the measured resistance value R _I.
If R _I > R ₉₀₀ , the process proceeds from step 6 to step 7 and the vaporizing glow plug 12 is energized. Here, the resistance value R ₄₀₀ when the vaporizing glow plug 12 is at 400℃
and the resistance value R _E of the vaporizing glow plug 12,
If the resistance value is 400°C or more, proceed to step 9, open the fuel valve 42, send oil to the combustor 1 via the vaporizing glow plug 12, vaporize the fuel, and ignite it with the ignition glow plug 13. do.

In step 4 above, if the resistance value R _I of the ignition glow plug 13 is lower than R ₁ , step 10 is performed.
Then, the signal T _AM from the temperature sensor 81 is read and the atmospheric temperature is checked. and the predetermined temperature T ₂
If it is higher, proceed to step 11 and energize the ignition glow plug 13. In step 12, the resistance value R _I of the energized ignition glow plug 13 is compared with the resistance value at 900°C, and if R _I > R ₉₀₀ , step 9
will proceed to. If the resistance value of 900°C has not been reached in step 12, the switch 13c connected in parallel to the control resistor 13a is closed in step 13, the control resistor 13a is short-circuited, and a large current is passed through the ignition glow plug 13. Measure the temperature rise. Then, after energizing for a predetermined time by a timer inside the electronic control unit 7, the energizing is turned off, and the process proceeds from step 14 to step 9.

Also, in step 10, if the atmospheric temperature is low and the predetermined temperature is
If T ₂ has not been reached, proceed to steps 15-17.
The ignition glow plug 13 is energized and the changeover switch 13c is turned on to short-circuit the control resistor 13b, and the timer processing of the electronic control unit 7 is used to energize the glow plug 13 for a predetermined period of time to raise the temperature rapidly, and then step 7
to move to. Note that steps 18 and 19 are steps for rapidly increasing the temperature as described above, and steps 20 and 21 are steps for rapidly increasing the temperature in the vaporizing glow plug 12.

After the vaporized fuel is ignited inside the combustor 1 in step 9 and combustion begins, in step 22 the hot air blower 22 is turned off and the combustion blower 11 is activated to achieve a good combustion condition. Wait for the time to pass (steps 23 and 24), and in step 25, the temperature signal from the flame sensor 14 installed in the combustor 1 is detected.
Check _TFS . When the temperature signal _TFS has reached the predetermined temperature _T3 at which the combustion condition is good, the process proceeds to step 26, where the hot air blower 22 is operated to blow hot air into the interior of the vehicle compartment 5.

In step 27, the temperature signal _THE from the heat exchanger temperature sensor 26 provided in the heat exchanger 2 is checked and compared with the abnormal temperature _T5 of the heat exchanger 2. If the abnormal temperature _T5 has not been reached, step 27 is executed. The process proceeds to step 29, but when _T5 has been reached, the process proceeds to step 28, where an abnormal signal is issued and the process proceeds to the combustion stop flow. Incidentally, if the temperature signal _TFS from the flame sensor 14 does not reach the predetermined temperature _T3 at step 25, the combustion condition is poor, and the process proceeds to step 28, where an abnormality signal is issued.

In step 29, the position of the hot air adjustment switch 82, which sets the internal temperature of the passenger compartment 5, is checked.
When the position is operated to the 1st position, the process proceeds to steps 30 and 31, and the fuel pump 41 and hot air blower 22 are controlled to the 1st position, respectively, to blow warm air into the vehicle interior.

In step 29, if the position is not the 1st position but the 2nd position, proceed to steps 33 to 36, and control the combustion blower 11, fuel pump 41, and hot air blower 22 to the 2nd position, which is stronger than the 1st position. Performs control to increase the temperature inside the vehicle.

If the hot air adjustment switch 82 is in the 3rd position, the process proceeds from step 33 to steps 37 to 39, in which the combustion blower 11, fuel pump 41, and hot air blower 22 are controlled to the strongest 3rd position, and the vehicle interior is controlled. This will control the internal temperature of No. 5 to be heated to a high temperature.

Next, in step 40, the amount of combustion air blown is maximized, and in step 41, the fuel flow rate is maximized, and the temperature of the flame sensor 14 at the maximum combustion state is
Tmax is checked, and if the temperature signal _TFS of the frame sensor 14 does not reach Tmax in step 42, the temperature signal is stored as an abnormality due to clogging of the fuel flow path. Then, in step 44, the fuel pump 41 is turned off to stop the fuel supply, and the heater is energized for a predetermined period of time under timer control in order to burn off the carbon adhering to the fuel flow path inside the vaporizing glow plug 12. Set +1 (step
45-48). In step 49, the counter N for energization for carbon incineration is set to a predetermined number of times N1.If the blockage in the fuel flow path cannot be removed even after performing the abnormal energization operation _N1 , the process proceeds to step 50, where an abnormality signal is issued to issue a warning. .

Note that the combustion blower 11 is not at the maximum position at step 40, the combustion pump 41 is at a position other than the 3rd position at step 41, and the flame sensor 14 is at the maximum position at step 42.
When the temperature signal is Tmax and the fuel pump 41 is supplying fuel in step 44, the process proceeds from each step to step 51 without carrying out the energization incineration process of the vaporizing glow plug.

In step 51, the temperature signal _TA from the room temperature meter 51 installed in the passenger compartment 5 is read, and if the temperature is higher than the desired temperature _T4 , the operation of the combustor 1 and related blowers, etc. is stopped. At step 53, both the warm air blower 22 and the combustion blower 11 are turned off, and the fuel pump 41 is reversed to recover the fuel inside the oil pipe to prevent pipe clogging due to carbonization caused by residual heat, and then the fuel pump is turned off. 41 is turned off (steps 54 and 55).

Incidentally, if the temperature signal T _A from the room temperature meter in step 51 does not reach the desired temperature T ₄ , the process returns to step 27 and repeats the flow.

In the above flow, as shown in steps 40 to 43 as part of the fuel flow path abnormality detection process, the combustion temperature when both the combustion air blowing amount and the fuel supply amount are maximized is determined by the temperature signal from the flame sensor. clogging of the flow path was determined by comparing it with the maximum combustion temperature using Then, when an abnormality is detected, clogging of the flow path may be determined by searching a map corresponding to the steps of the air flow amount and the fuel supply amount.

The present invention has been described above with reference to the above embodiments, but various modifications can be made within the scope of the invention, and although this embodiment has been explained by taking a heater that sends warm air into a vehicle interior as an example, general This can be applied to detecting abnormality in the fuel flow path of a heater, and these are not excluded from the scope of the present invention.

(Effects of the Invention) According to the present invention, when an abnormality is detected in the fuel flow path, the amount of combustion air blown and the amount of fuel supplied are maximized,
The combustion temperature in this state is checked and compared with the combustion temperature when the flow path is good to determine if the flow path is clogged.
This has the effect of allowing detection of carbon adhesion to the flow path.

In addition, when a blockage in the flow path is detected, the fuel supply is stopped and the heater of the vaporizing glow plug is energized, so the fuel flow path of the vaporizing glow plug becomes dry and the attached carbon is removed. It has the effect of being incinerated and removed. Therefore, the heating efficiency of the heater is restored and a good heating effect can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the fuel flow path abnormality detection device for a heater according to the present invention, and FIG. 2 is a process flow diagram showing an example of the process. 1... Combustor, 2... Heat exchanger, 5... Vehicle compartment,
7...Electronic control device, 11...Combustion blower, 12
...Vaporizing glow plug, 14...Flame sensor, 41...Fuel pump.

Claims (1)

[Claims] 1 In a fuel flow path abnormality detection device for a heater that recovers heat generated by burning a fuel mixture in a combustion chamber using a heat exchanger and uses the recovered heat for heating, the amount of combustion air blown and the amount of fuel supplied are determined. a storage means for storing a map comparing normal combustion temperature with respect to a normal combustion temperature; an air volume detection means for detecting the amount of combustion air blown; a fuel supply amount detection means for detecting the amount of fuel supplied; temperature detection means; a search means for searching a standard combustion temperature from a map of the first storage means using the detected air flow rate from the air flow rate detection means and the fuel supply amount detected by the fuel supply amount detection means; The standard combustion temperature detected by the temperature detection means is compared with the combustion temperature detected by the temperature detection means, and when the combustion temperature is lower than the standard combustion temperature, an alarm is issued, the fuel supply is stopped, and the fuel flow path is heated by the heating means. A fuel flow path abnormality detection device for a heater, comprising: a control means for burning residue.