JPS62279274A - Controller for glow plug electric energization - Google Patents

Abstract

PURPOSE:To prevent any needless electric energization of a glow plug, by starting heating of the glow plug, in the case when a key switch control position is in the operation position and the state without starting engine is continued over a predetermined time. CONSTITUTION:In a control unit 7, the start in electric energization of a glow plug 1 is controlled by a delay timer 25. When a driver judges that preheating required, and wait for a predetermined time or more while holding the control position of a key switch 8 in the operation position 8A a timer signal is outputted from the delay timer 25 so as to start the electric energization of the glow plug 1. On the other hand, when the driver judges that the preheating is not required, and immediately sets the control position of the key switch 8 in the starting position 8B, the timer signal is not outputted from the delay timer 25, thereby the electric energization of the glow plug is not started so that the cranking is made without preheating. Therefore, the driver, judges whether the preheating is required or not. According to the control time of the key switch 8.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an energization control device for a glow plug used when starting a diesel engine at a low temperature, etc. The present invention relates to a device capable of preventing.

[Conventional technology]

Glow plugs heat the inside of the combustion chamber of a diesel engine, making the engine easier to start. In the conventional glow plug energization control device, energization to the glow plug is started from the moment the key switch of the vehicle is operated from the stop position (OFF position) to the operating position (ON position), and the required preheating time Pk-! ! It is widely used to turn off the indicator lamp after the preheating time has elapsed to inform the driver that preheating has been completed, and then start the engine.

However, if the glow plugs are uniformly energized at the time of starting, the glow plugs will be energized even when preheating is not required, such as when the engine is sufficiently warm, which will extend the lifespan of the glow plugs. It becomes a factor that reduces the For this reason, the engine cooling water temperature is detected, for example 50°C.
In the above cases, a device that does not energize the glow plug has also been proposed (Public Act No. 54-20529).
issue).

However, whether or not it is necessary to energize the glow plug is not simply determined by the coolant temperature, but is also influenced by the engine's combustion performance and the like as well as the intake air temperature. Therefore, even if the coolant temperature is high, the engine may be difficult to start without preheating the glow plug due to a drop in the fuel pump 3, requiring long cranking times, or producing white smoke in the exhaust. There was a problem that there was.

[Problem that the invention seeks to solve]

The present invention has been made to solve the above-mentioned problem, α, and starts energizing the glow plug according to the natural key switch operation method according to the driver's judgment that preheating is necessary or unnecessary. It is an object of the present invention to provide a glow plug energization control device that can be turned on and off and can prevent unnecessary energization to a glow plug.

[Means for solving problems]

Therefore, in the present invention, the operating position includes an operating position that enables the engine to be operated and a starting position that operates the starter, and the starting position is located next to the operating position so that the operating force to the starting position is not lost. a key switch that automatically returns to the operating position when the engine is turned, a start detection means that detects the start of the engine, and when the operation position of the key switch is the operating position and the engine is not started for a predetermined period of time or more; A glow plug energization control device is provided, comprising: timer means for outputting a timer signal at a timer; and glow plug energization means for starting heating of the glow plug in response to the timer signal from the timer means.

[Effect]

In the present invention, if the driver determines that preheating is not necessary at the time of starting, he will immediately turn the key switch from the operating position (○N position) to the starting position (ST position 11) that operates the starter; Note that if the driver decides that preheating is required, he will leave the key switch in the operating position and wait for the preheating time, then turn it to the start position and start cranking. This is what I did.

According to the configuration of the present invention, if the driver determines that preheating is necessary and waits for a predetermined time or longer with the key switch in the operating position, 1. A timer signal is output from the timer means and energization of the glow plug is started. Therefore, the engine can be started with the glow plug heated and preheated.

On the other hand, if the driver determines that preheating is not necessary and immediately sets the key switch to the start position, the timer means does not output a timer signal, so energization to the glow plug does not start and preheating occurs. Cranking is performed without any problem. Additionally, if the driver makes a mistake in judgment and the engine does not start after a short period of cranking, by returning the key switch to the operating position and waiting for a predetermined period of time, a timer signal is output from the timer means and a signal is sent to the glow plug. Power supply starts. Therefore, the next startup can be made easier. As mentioned above, if the engine does not start even after cranking, it is a very natural operation to return the key switch from the starting position to the operating position, take a short break, and then try cranking again.

〔Example〕

An embodiment of the present invention will be specifically described with reference to the drawings.

Figure 1 is a circuit diagram of a glow plug energization control device according to the present invention.

Glow plugs 1 provided for each diesel engine are connected in parallel, and a temperature detection resistor 2 and a current limiting resistor 3 are connected in series. Since a four-cylinder engine is assumed here, there are four glow plugs 1. The voltage of a battery 6, which is a vehicle power supply, is applied to the temperature detection resistor 2 through the contacts of the main relay 4, and the voltage of the battery 6 is applied to the current limiting resistor 3 through the contacts of the sub-relay 5. The glow plug 1 is a resistance heating element with a positive temperature coefficient of resistance, and when a constant VR voltage is applied, it
It is designed to achieve thermal equilibrium at an equilibrium temperature of around 50°C. The rated voltage of the glow plug 1 is set to about 172 times the voltage of the battery 6.

When the main relay 4 is energized, the voltage of the battery 6, that is, a voltage higher than the rated voltage, is directly applied to the glow plug 1 via the temperature detection resistor 2, and the glow plug 1 is rapidly heated. Also,
When only the sub-relay 5 is energized and a voltage is applied through the current limiting resistor 3, approximately the rated voltage is applied to the glow plug 1, and stable preheating is performed. These relays 4.5 control 1. :y, controlled and excited by the unit 7.

The control unit 7 is supplied with vehicle power from a battery 6 via a key switch 8. The control unit 7 detects the voltage across the temperature detection resistor 2, energizes the fills 4A and 5A of each relay 4.5, and turns on the preheating indicator lamp 9.

The key switch 8 is in the operating position, the stop position (○FF position), and the operating position fi!, which allows the engine to be rotated 'y1'. t
It has three operating positions: (ON position) and starting position N (ST position) where the starter is operated and cranked. Then, the starting position is located at the operating position next to the operating position,
When you release your finger from the key switch 8 and lose the operating force to the starting position, it automatically returns to the operating position. Operating position a contact (ON
Contact point) 8A is supplied with voltage from the battery 6 when the operating position and starting position are selected, and supplies power to the control unit 7. Starting position contact, Katsu (ST contact) 8B,
When the starting position is selected, the voltage of the battery 6 appears and gives a high level signal to the control unit 7.

Further, signals from a water temperature sensor 10 and a charge lamp relay 11 are given to the control unit 7 . The water temperature sensor 10 is composed of a thermistor and detects the temperature of the cooling water.

The contact of the charge lamp relay 11 is a normally closed contact, and when the engine completes starting and an alternator (not shown) starts generating electricity, the rL contact is energized and opened. The charge lamp relay 11 is intended to turn on a charge lamp (not shown) while the alternator is not generating power, but here it constitutes a start detection means for detecting the start of the engine. Then, when the engine has completed starting, a high level signal is given to the control unit 7.

The internal configuration of the control unit 7 will be explained.

I+-Ira/l'Sako-Kusuyamatake 98? ↓ The resistance value of the glow plug 1 is detected from the voltage ratio between the glow plug 2 and the glow plug 1, and when the resistance value exceeds a predetermined value, the output 20a is inverted to a high level. Since the resistance value of the glow plug 1 increases approximately in proportion to the temperature like a normal metal body, the temperature of the glow plug 1 is detected as a result. And glow plug temperature detection section 20
The glow plug 1 has a hysteresis characteristic so that the temperature of the glow plug 1 when the output 20a is reversed from low level to high level is about 900°C, and the temperature at which the output 20a returns from high level to low level is about 800°C. ing.

The water temperature detection section 21 includes a water temperature sensor 10 consisting of a thermistor.
The output 21a is inverted to high level when the cooling water temperature is 50°C or higher. Further, water temperature information from the water temperature sensor 10 is transmitted to a preheating display timer section 22 and an afterglow timer section 23.

The preheating display timer unit 22 turns on the preheating display lamp 9 during 7 seconds.
．． This is a timer for setting tr'5rll for several seconds, as shown in FIG. The output 22a is set to low level, and the lamp driving section 2
4, the preheating indicator lamp 9 is turned on.

77 The timer unit 23 is a timer for setting the time for stable preheating of the glow plug 1 after rapid heating, and starts from the time when the glow plug 1 starts to be energized, as shown in Fig. 3. , the output 23a is set to a low level for several tens of seconds in response to the cooling water temperature, and the coil 5A of the sub-relay 5 is energized via the sub-relay drive unit 40. Further, the afterglow timer section 23 has a reset input terminal 23C, and while the reset input terminal 23C is at a high level, that is, while the start position (ST position buy) is selected by the key switch 8, the output 23a is maintains the low level and continues to excite the sub-relay 5A, and the after-glow timer shown in FIG. 3 restarts from the time when the reset input terminal 23C is inverted to the low level.

The start of energizing the glow plug 1 is controlled by a delay timer 25. The delay timer 25 is connected to the MJiy input terminal 2.
5B, reset input terminal 25C and inhibit input terminal 25D
It has three input terminals. And signal input terminal 25
A predetermined time from the time when B becomes high level, here 0
．． The basic operation is to invert the output 25a to high level when 7 seconds have elapsed, and while the reset input terminal 25C is at high level, the output 25a remains at low level, and when the reset input terminal 25C is inverted to low level. From then on, counting of the predetermined time (0.7 seconds) is started. Further, when the inhibit input terminal 25D is at a low level, the 0
．． The predetermined time of 7 seconds is set to zero, and as soon as the signal input terminal 25B becomes a high level, the output 25a is inverted to a high level.

The reset input terminal 25C of the delay timer 25 is connected via two N0Ry'-) 26.27. Signals from the starting position contact 8B of the -1-X switch 8 and the charge lamp relay 11 are input. And N011'-) 27
The output 25a of the delay timer 25 is input to one of the input terminals, and only when the output 25a of the delay timer 25 is in a low level state, it is reset by a high level signal from the starting position, α8B or charge lamp relay 11. Input terminal 25C is set to high level.

The inhibition input terminal 25D of the delay timer 25 is connected to the water temperature detection section 21.
Output 21al: Connected and set to low temperature when the cooling water temperature is below 50°C.

Delay timer 25 and two NOR dates 26.2 above
7, the key switch 8 is in the operating position (1! (ON)
position) and the engine is not started for a predetermined period of time (0.7 seconds) or more, the timer means outputs a timer signal (a signal that sets the output 25a to a high level). ing.

The predetermined time of the timer means is determined by the prohibition input terminal 25D when the cooling water temperature is below a predetermined temperature (50"C).
The signal to r) is set to zero time.

The output 25a of the delay timer 25 is the afterglow timer section 2.
3 and the bird are connected to the generator 28 7.2-1-7
In other words, the timer signal activates the afterglow timer section 23 to start excitation of the coil 5A of the sub-relay 5, and the trigger generates the timer signal from the generation section 28. A pulse l1ii0°1 second trif y signal corresponding to the rising differential pulse of is sent to the fin relay drive unit 30, and excitation of the fill 4A of the main relay l] is started.

The main relay drive unit 30 has two input terminals, an input terminal 30B to which the above-mentioned signal is input, and a signal input terminal 30C. When the signal input terminal 30C is at a low level, the input terminal 30B is instantaneously brought to a high level, and then the fill 4A of the main relay 4 is turned on until the signal input terminal a OC is set to a high level. Exciter B.

The signal input terminal 300 of the main relay drive section has three inputs O.
The output of R date 31 is connected. Three input OR date 3
1 is the output 23a of the afterglow timer section 23.
, the output 20a of the glow plug temperature detection section 20, and VAN
The output 32a of the D date 32 is connected. A N D date 32 is a date having an inverting input terminal in which one of its inputs is inverted. A signal from the start position (ST) contact 8B of the key switch 8 is input to the inverting input terminal, and a signal from the charge lamp relay 11 is input to the positive input terminal. The output 32a of the AND date 32 becomes high level when the contact of the charge lamp relay 11 is open and the key switch 8 is not in the starting position 8B and cranking is not being performed, so the engine has completed starting. This is when it is in a self-destructive rotation. Therefore, the main relay driving section 30 is configured such that the main relay drive section 30 is configured to
After receiving fM, the temperature of glow plug 1 is 900°C.
The fin relay 4 is energized until the start is completed or the charge lamp relay 11 opens and the glow plug 1 is activated.
Continue rapid heating. In addition, afterglow timer section 23
The reason why the rapid heating is terminated when the output 23a becomes high level is for safety reasons.

The above birds are the generation part 28, the main relay drive*J part 30,
The three-input OR date 31, the afterglow timer section 23, the sub-relay drive section 40, and the like constitute a glow plug energizing means that starts heating the glow plug 1 in response to a timer signal 25a from the delay timer 25.

The output 32a of the AND date 32, which indicates the completion of starting, is transmitted to the lamp driving section 24 via the * and ○R circuits 33. This is because the preheating indicator lamp 9 is turned off when starting is completed, regardless of the output 22a of the preheating indicator timer section 22.

The operation will be explained based on the above configuration.

FIG. 4 is a timing chart showing the operation when the driver considers that preheating is necessary and performs the operation. Cooling water temperature is 50°
Expected to be C or higher.

The driver moves the key switch 8 to the operating position (ON position i!ff1
) and wait for the preheating indicator lamp 9 to go out, then operate it to the starting position (ST) to start cranking.

When the key switch 8 is placed in the operating position, the delay timer 2-5 starts counting time, and after a predetermined time to (o, 7 seconds) has elapsed, its output 25a becomes high level. Then, the trigger signal 28a is output from the trigger generator 28, and the main relay 4 is started to be energized, and the sub relay 5 is also energized. As a result, energization of the glow plug 1 is started and rapid heating is started. When the glow plug 1 reaches 900°C, the output 20a from the glow plug temperature detection section 20
becomes the NO1 level, and the main relay 4 is turned off. After that, current is supplied to the glow plug 1 by the sub-relay 5 via the current-limiting resistor 3, and stable preheating is maintained at 77.
It continues for the time set in the tag timer section 23. When the key switch 8 is set to the start position in this state, the engine will start easily because the glow plug 1 will be preheated.
The contact of the charge lamp relay 11 opens, and at this time, the output 25a of the delay timer 25 is already at the 1 level, so the NOR date 27 is intercepted, the starting mh position of the key switch 8 is replaced, and the signal from α8B is signal or the signal from the charge lamp relay 11) Therefore, the output 25a of the delay timer 25 remains at a high level,
Stable preheating of the glow plug 1 continues until the predetermined time set by the afterglow timer section 23 has elapsed.

FIG. 5 is a timing chart showing the operation when the driver considers that preheating is unnecessary. Cooling water temperature is 50℃
The above is assumed.

The driver suddenly operates the key switch 8 from the operating position (ON position) to the starting position e (ST position) without waiting for a breath to start cranking.

In this case, the delay timer 25 is set for a predetermined period of time LO (0,
7 seconds), the start position contact 8B is set to high level. At this point, the output 25a of the delay timer 25 is still at low level, so the NOR date 27 is open, and the signal from the starting position contact 8B causes the reset input terminal 25C to go high, and the output 25a of the delay timer 25 maintains the lotu level. Then, due to the high level signal from the engine, the reset input terminal 25C of the delay timer 25 becomes high level, and the output 25
a is kept at low level. Since the output 25a of the delay timer 25 never reaches a high level, the trigger generation section 28 and afterglow timer section 23 do not operate, and the main relay 4 and sub-relay 5 are not energized. Therefore, unnecessary energization of the glow plug 1 can be prevented.

FIG. 6 is a timing chart p-) showing the operation when the driver thinks that preheating is unnecessary, but fails to start the engine by initial cranking. The cooling water temperature is assumed to be 50°C or higher.

The driver suddenly presses the key switch 8 to the start position (ST position W).
Although the engine was cranked by operating up to 1), the engine did not start, so the key switch 8 was temporarily returned to the operating position 1 (ONN position), and after waiting for a breath, the engine was attempted to start again.

In this case, in the first cranking operation (indicated by Pl in the figure), the key switch 8 is at the starting position rf!, similar to the operation explained in FIG. Timing by the delay timer 25 is interrupted by the signal from the contact 8B, and the glow plug 1 is not energized. However, when the key switch 8 is returned to the 'i1'lR position and the signal from the starting position contact 8B falls to the low level by one level, the engine still does not start and the signal from the char 7 lumen relay 11 remains at the low level. The reset input terminal 25C to the delay timer 25 also goes to low level.
t', and the delay timer 25 starts counting from this point.

Thereafter, in the same manner as the operation shown in FIG. 4, rll! will be activated at a predetermined time from the time when the key switch 8 is returned to the operating position. t.

After (0.7 seconds) has elapsed, the output 25a of the delay timer 25 becomes high level, each relay 4.5 is energized, and energization to the glow plug 1 is started. Therefore, the engine can be easily started during the next cranking operation (indicated by P2 in the figure).

FIG. 7 is a timing chart showing the operation in the case where the driver operates the engine thinking that preheating is not necessary, and although the engine starts once, the starting is not sufficient and the engine immediately stalls.

In this case, the operation proceeds in substantially the same manner as described in FIG. The difference is that once the engine starts, the signal from the charge lamp relay 11 becomes high level, so the reset input 25C of the delay timer 25 is kept high level during that time. When the engine stalls and the signal from the char 7 lamp relay 11 falls to low level, the delay timer 25 restarts timing for a predetermined period of time LO (0
, 7 seconds), energization of the glow plug 1 is started.

For this reason, the next cranking 1! ! , tt'' (indicated by P2 in the figure), the engine can actually be started.

In each of the above four operation examples, the cooling water temperature is s o
'c or higher was assumed. When the cooling water temperature is below 50°C, the output 21a from the water temperature detection unit 21 causes the inhibit input terminal 25D of the delay timer 25 to go low, and the delay timer 25 uses the timer function to control the operation of the key switch 8. After the liχ8B reaches the high level, the output 25 is operated to the operating position fi (ON position), and at the same time, energization to the glow plug 1 is started, and the same operation as a conventional glow plug energization control device is performed. It will be done. As a result, when the coolant temperature is low, the glow plug is unconditionally energized and heated, making it easier to start the engine.

As mentioned above, this example is the beginning! # When the driver thought that preheating was not necessary, he immediately performed the cranking operation, and when he thought that preheating was necessary, Hiiragi once operated the key switch 8 to the operating position, took a breath, and then performed the cranking operation. In addition, if the engine does not start after a short period of cranking, the glow plug is operated in a very natural manner, such as returning the key switch 8 from the starting position to the operating position, taking a breather, and then attempting the cranking operation again. This is to determine whether or not it is necessary to energize 1. Therefore, it is possible to prevent unnecessary energization of the glow plug 1, and if starting fails, energization and heating of the glow plug 1 is automatically started immediately, allowing the driver to make the following decisions. It has the advantage of also having a backup function against errors.

In addition, a delay timer 2 is used as a standard for determining the driver's intention.
The predetermined time opening 10 of No. 5 is preferably set in a range of about 0.5 seconds to 1.5 seconds, and preferably about 0.7 seconds.

In the embodiment described above, when the driver immediately performs a cranking operation, the glow plug 1 is not energized at all, so that the glow plug 1 is not energized at all. P! by the main relay 4, which has a large effect on the life of the glow plug 1! , it is also possible to adopt a method in which only continuous heating is not performed.

Further, in the embodiment described above, the cooling water temperature is detected, and if the water temperature is below a predetermined temperature, energization heating is performed unconditionally, but the determination may be made by detecting not only the cooling water temperature but also the intake air temperature. Alternatively, it is also possible to adopt a system in which the operation of the delay timer 25 is not affected by the cooling water temperature, intake air temperature, etc.

It goes without saying that the present invention can be applied not only to a glow plug energization control device that detects the temperature of the glow plug 1 as in the embodiment described above, but also to control devices that use other methods.

〔Effect of the invention〕

As described above, the present invention has the above configuration and determines the driver's intention based on the time it takes to operate the key switch. It is possible to start or stop energizing the glow plug according to the natural switch operation, and therefore has the excellent effect of preventing unnecessary energization of the glow plug. In addition, if the driver makes a mistake in judgment and fails to start the engine, power to the glow plugs is automatically started immediately, so there is no need to crank for a long time or produce white smoke in the exhaust. It has the excellent effect of preventing this from happening.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a circuit diagram, and FIG. 2 is a circuit diagram.
Figure 3 and Figure 3 are characteristic diagrams showing the relationship with cooling water temperature.
7 to 7 are timing charts for explaining the operation. 1... Glow plug, 2... Temperature detection resistor, 3...
...Current limiting resistor, 4...Main relay, 5...Sub relay, 8...Key switch, 9...Preheating indicator lamp, 10...Temperature sensor, 11...Charge lamp relay (starting) detection means), 25...delay timer, 2
6.27...NOR date. f-ゝ, 1 agent patent attorney 7m after: Yusaku: 1. Patent Attorney Sat 111 Akira Makoto, “Cho No. 2 (21 Samurai or Tree!/L('C)

Claims (1)

[Scope of Claims] 1 The operating position includes an operating position where the engine can be operated and a starting position where the starter is activated, and the starting position is located next to the operating position and the operating force to the starting position is lost. a key switch that automatically returns to the operating position when the key switch is turned off; a start detection means that detects the start of the engine; 1. A glow plug energization control device comprising: timer means for outputting a timer signal when the timer is activated; and glow plug energization means for starting heating of the glow plug in response to the timer signal from the timer means. 2. The glow plug energization control device according to claim 1, wherein the predetermined time of the timer means is about 1 second. 3. Means for setting the predetermined time of the timer means to zero or almost zero when temperatures related to engine starting characteristics such as engine cooling water temperature and intake air temperature are below a predetermined time. A glow plug energization control device according to claim 1.