JPS6228708Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a starting assist device for a diesel engine, and more particularly to a starting assist device for a diesel engine that controls the temperature of a glow plug of a diesel engine and has improved starting characteristics.

FIG. 1 is a schematic block diagram of a conventional starting aid device. In the figure, ignition switch 1
The ignition switch 1 is used to start the diesel engine, and power is supplied to the controller 2 from the battery 10 via the ignition switch 1. The controller 2 includes an input section 21 and a control section 22.
, a timer 23 , a comparator 24 , and an output section 25 . The ON contact of the ignition switch 1 is connected to the input section 21, and the ST contact is similarly connected to the input section 21. Further, a water temperature switch 9 is connected to this input section 21. This water temperature switch 9 is for detecting the temperature of the cooling water of the diesel engine. A timer 23 is provided in connection with the control section 22. This timer 23 measures the time required to turn on an indicator lamp 3, which will be described later. Further, an output section 25 is connected to the control section 22 . The indicator lamp 3, the first glow relay 4, and the second glow relay 5 are connected to the output section 25. Both of these glow relays 4 and 5 are for controlling energization of the glow plug 8. For this purpose, power is supplied to the first and second glow relays 4 and 5 from a battery 10. And the first glow relay 4
is the glow plug 8 via the sensing resistor 7.
The second glow relay 5 is connected to the glow plug 8 via the dropping resistor 6 and the sensing resistor 7. Both ends of sensing resistor 7 are connected to comparator 24 . This comparator 24 is for detecting a temperature change of the glow plug 8 based on the resistance value of the sensing resistor 7, and transmits the detection signal to the control section 2.
Give to 2.

Figure 2 is a waveform chart for explaining the operation of Figure 1. In particular, Figure 2 a shows the case where the cooling water temperature is 50°C or less, and Figure 2 b shows the case where the cooling water temperature is 50°C or higher. show.

Next, the operation shown in FIG. 1 will be explained with reference to FIG. First, when the water temperature is below 50° C., the water temperature switch 9 is turned OFF, and when the ignition switch 1 is turned ON, the signal is given to the control section 22 via the input section 21. Control part 2
2 turns on the indicator lamp 3 via the output section 25. At the same time, current is also applied to the coil of the first glow relay 4 to turn on its contacts. As a result, power is supplied from the battery 10 to the glow plug 8 through the contacts of the first glow relay 4 and the sensing resistor 7, causing it to become red hot. The energization time of the indicator lamp 3 is fixed to a predetermined value, and the ignition switch 1 is turned off at the same time as the indicator lamp 3 turns off.
switch to ST position and start the diesel engine. In the ST position, the indicator lamp 3 remains lit and the first glow relay 4 also closes its contacts. Further, the control unit 22 also operates the second glow relay 5 in response to the ignition switch 1 being switched to the ST position. Therefore, the second glow relay 5,
Power is supplied to the glow plug 8 via the dropping resistor 6 and the sensing resistor 7. Then, the temperature of the glow plug 8 continues to rise gradually. The voltage drop across the sensing resistor 7 has a value that correlates with the temperature of the glow plug 8. The voltage across the sensing resistor 7 is compared by the comparator 24, and a detection signal corresponding to the temperature is given to the control unit 22. It will be done. Then, when the glow plug 8 reaches the target temperature, the control section 22 turns off the first glow relay 4. Thereby, only the second glow relay 5 is energized to the glow plug 8. Once the engine has started, the ignition switch 1 is returned to the ON position, and the control unit 22 turns on the second glow relay 5.
At the same time, turn off the injector lamp 3.

Next, a case where the water temperature is 50°C or higher will be explained. In this case, water temperature switch 9 is turned on,
As shown in FIG. 2b, the lighting time of the indicator lamp 3 is short, the first glow relay 4 is not turned on, and only the second glow relay 5 is energized to the glow plug 8.

By the way, since the conventional glow plug control device is configured as described above, a dedicated sensing resistor 7 is required to detect the resistance value due to temperature change of the glow plug 8, and the number of parts configuring the device increases. Moreover, control is complicated. In addition, the voltage drop caused by the sensing resistor 7 acts as a power loss when the capacity of the battery 10 decreases or when the voltage of the battery 10 decreases at low temperatures, and thus becomes a factor that prevents the temperature of the glow plug 8 from rising at the time of starting. Furthermore, if the water temperature is below 50°C, it is necessary to turn the ignition switch 1 to the ON position and then wait until the indicator lamp 3 goes out after a predetermined period of time. Since this time is determined assuming the worst case for starting, there are drawbacks such as having to wait for a certain period of time even when it is not necessary.

Therefore, the main purpose of this invention is to provide a starting assist device for a diesel engine which has a simple structure, causes less power loss, and is inexpensive, in order to eliminate the above-mentioned drawbacks.

To summarize this invention, in response to the ignition switch being turned on, the second energization control means is turned on for a short period of time to energize the glow plug, and the first energization control means is turned off. and detects a voltage correlated to the temperature state of the glow plug, and when the glow plug reaches a predetermined temperature, determines the conduction time of the first energization control means, and controls the first energization control means to be in a conduction state for that time. It is composed of

The above objects and other objects and features of the present invention will become clearer from the detailed description given below with reference to the drawings.

FIG. 3 is a schematic block diagram of one embodiment of this invention. This FIG. 3 is the same as the above-mentioned FIG. 1 except for the following points. That is, the controller 20
In this case, a voltage detector 27 is used instead of the above-mentioned comparator 24.
will be provided. This voltage detector 27 detects the potential difference between both ends of the glow plug 8. Therefore, the sensing register 7 shown in FIG. 1 is omitted.

FIG. 4 is a waveform diagram for explaining the operation of FIG. 3.

Next, the operation shown in FIG. 3 will be explained with reference to FIG. When the ignition switch 1 is switched to the ON position, the control unit 22 lights up the indicator lamp 3 and sends a short-time signal to the output unit 25 to drive the glow relay 5 as the second energization control means. give. This signal activates the second glow relay 5 for a short period of time, for example about 0.1 seconds. Thereby, power is supplied from the battery 10 to the glow plug 8 for that period of time via the limit register 61. At this time, the voltage detector 27 detects the voltage across the glow plug 8. In other words, if the resistance value of the limit resistor 61 is appropriately selected, the temperature of the glow plug 8 can be increased from room temperature to 900°C.
When the voltage changes within the range of .degree. C., the voltage value detected by the voltage detector 27 also changes between 1.9V and 6.4V. This voltage naturally changes depending on the voltage of the battery 10, but the second glow relay 5 and the limit resistor 61
Since the current flowing through the glow plug 8 is limited by the limiting resistor 61, and the energization time is very short, for example, 0.1 seconds, a decrease in capacity due to aging or a decrease in battery at low temperatures does not cause a large error. By detecting this voltage, the temperature state of the glow plug 8 at that time can be detected. This detected voltage value is given to the control section 22. Using this voltage value, it is quickly calculated how many seconds (t1) the first glow relay 4 should be operated in order to raise the glow plug 8 to the target temperature (for example, 900° C.).
Then, a signal corresponding to that time is given from the timer 23 to the output section 25 via the control section 22.
Then, the first glow relay 4 becomes conductive only during t1, and the glow lamp is heated.

On the other hand, the control section 22 controls the ignition switch 1
The indicator lamp 3 is turned on at the same time as it is turned on, and is turned off after a predetermined period of time has elapsed. The driver then turned on the ignition switch 1.
Switch from the ON position to the ST position. depending on,
The control unit 22 activates the second glow relay 5 again. As a result, even after the first glow relay 4 is cut off, it is energized by the second glow relay while the ignition switch 1 is in the ST position, and the temperature of the glow plug 8 is kept constant. It will be done.

Although the water temperature switch 9 was not mentioned in the above-described embodiment, the water temperature switch 9 may be used to switch between the first glow relay 4 and the second glow relay 5 in the same manner as in the past. . Also, for the second operation time of the second glow relay 5, the ignition switch 1 is turned to ST.
After switching to the ON position, a timer or the like may be used to continue the operation even after switching to the ON position. Further, the lighting time of the indicator lamp 3 may be a fixed time or may be determined in accordance with the voltage detected by the voltage detector 27.

As described above, according to this invention, the conventional sensing resistor is omitted, and in response to the ignition switch being turned on, the second energization control means is made conductive for a short period of time, and the glow plug is turned on. Since the first energization control means is turned on, a voltage correlated to the temperature of the glow plug is detected, the conduction time of the first energization control means is determined, and the first energization control means is brought into a conduction state.
The configuration can be simplified, power loss can be reduced, and the device can be made inexpensive. Furthermore, since the second energization control means is made conductive for only a short period of time, a decrease in capacity due to aging or a decrease in battery voltage at low temperatures will not cause a large error.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram of a conventional starting assist device for a diesel engine, and FIG. 2 is a waveform diagram for explaining its operation. FIG. 3 is a schematic block diagram of one embodiment of this invention, and FIG. 4 is a waveform diagram for explaining its operation. In the figure, 1 is the ignition switch, 3
is an indicator lamp, 4 is a first glow relay, 5 is a second glow relay, 8 is a glow plug, 20 is a controller, 27 is a voltage detector, 6
1 indicates a limit register.

Claims (1)

[Claims for Utility Model Registration] (1) An ignition switch for starting a diesel engine, a glow plug used as a starting aid for the diesel engine, and a first energizer for controlling energization to the glow plug. A starting auxiliary device for a diesel engine, comprising: a control means; and a second energization control means that controls energization of the glow plug via a limiting resistor that limits energization of the glow plug. voltage detection means for detecting a voltage correlated to the temperature state of the ignition switch; Starting control that puts the energization control means in a cut-off state, determines the conduction time of the first energization control means according to the detection signal of the voltage detection means, and conducts the first energization control means for the determined conduction time. Starting aid for diesel engines, with means. (2) The utility model registration claim further includes a display means for displaying the energization state of the glow plug, and the start control means lights up the display means in response to a detection signal from the voltage detection means. A starting aid for a diesel engine according to item 1.