JPS628383Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a glow plug preheating device for a diesel engine, and more specifically, a device that can heat the glow plug even after the engine has started, in order to reduce black smoke emissions after a cold start of the diesel engine. Regarding.

Compared to gasoline engines, diesel engines produce a large amount of black smoke (soot) in the exhaust gas during engine operation.
contains problems such as emitting unpleasant odors and obstructing visibility. In particular, immediately after a cold start, the combustion conditions are poor due to the low engine temperature, resulting in incomplete combustion and the generation of black smoke.

However, in recent years, it has been found that heating the combustion chamber after a cold engine start reduces black smoke emissions.

By the way, conventionally, as a device for heating the combustion chamber of a diesel engine, a glow plug is installed inside the combustion chamber, and before the engine starts, the glow plug is energized to heat the inside of the combustion chamber, thereby assisting the starting of the diesel engine. It is used. In this type of device, for example, as shown in Japanese Unexamined Patent Publication No. 49-100427, when power is turned on to the glow plug control device, energization to the glow plug is started, and the rotation speed detection circuit causes the engine to rotate. The glow plug is configured to detect the number of revolutions and stop energizing the glow plug when the engine reaches its own rotation speed.

Therefore, the glow plug is energized from before the engine starts until just after the engine is started, and once the engine has completely exploded, the glow plug is turned off. According to this device, since the glow plug is energized until the engine completely explodes, starting performance is certainly improved, but since the energization to the glow plug is stopped after the engine has completely exploded, it produces a large amount of black smoke. No consideration was given to countermeasures against black smoke generated during warm-up operation. Furthermore, the configuration is extremely complex because it uses a rotational speed detection circuit, specifically a circuit that detects the rotational speed based on the frequency of the alternator, to detect the initial and complete explosion of the engine. , and reliability is also decreasing.

Therefore, in view of the shortcomings of the prior art described above, the purpose of the present invention is to effectively suppress the emission of black smoke during warm-up operation while ensuring the startability of a diesel engine, and to have a very simple structure. The object of the present invention is to obtain a glow plug preheating device for a diesel engine.

The configuration of the present invention includes a first timer that starts operating when the operating switch is switched from the OFF position to the ON position and operates for a predetermined time; and a second timer that starts operating when the generated voltage of the generator driven by the engine reaches a predetermined voltage and operates at least until after the engine has completely exploded, and is activated by the outputs of the two timers when they are activated. The feature is that the glow plug is energized through the relay.

The first timer performs preheating before starting, as in the conventional case, and if its operating time is varied depending on the cooling water temperature, etc., starting performance is further improved.

The second timer is used to set the time during which the glow plug is energized during warm-up operation, and its operation is started when the operation switch is switched from the ST position to the ON position or when the generator driven by the engine is turned on. This is done when the generated voltage reaches a predetermined voltage, so a complicated rotational speed detection circuit that is conventionally required is not required, and a simple configuration can be achieved. To detect when the generated voltage of the aforementioned generator reaches a predetermined voltage, it is possible to easily detect a signal from a charge lamp installed in the driver's seat of the vehicle in which the diesel engine is installed. can.

The operating time of the second timer is set so that the glow plug can be energized even after the engine has completely exploded.
Set as appropriate.

Note that, like the first timer, if the operating time of the second timer is changed depending on the cooling water temperature, etc., more accurate control becomes possible.

In addition, the first timer performs preheating before startup, and the second timer performs preheating after startup, so the operating time of each timer can be freely set, and signals for starting operation can be input separately. Therefore, the configuration is simpler than using just one timer.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment of the present invention, in which 1 is a battery, 2 is an operation switch having an OFF position, an ON position 3, and a start position 4 (hereinafter referred to as ST position 4). Line 1 when connected
5 only, track 1 when connected to ST position 4
6 and the line 15 at the same time. 5 is a glow plug, 6 is a relay that controls energization to the glow plug 5, and 7 is a control circuit that drives the relay 6. The control circuit 7 is configured as follows.

8 is operation switch 2 from OFF position to ON position 3
The first timer is a first timer that starts operating when the switch is switched to ST, and stops operating after a predetermined time determined by a sensor 9 that detects the water temperature of the engine. This is a second timer that starts operating when switched and ends operating after a predetermined time. The operating time of the second timer 10 is set to be longer than the time from when the operating switch 2 is switched from the ST position 4 to the ON position 3 until the engine completely explodes. The outputs of the first timer 8 and the second timer 10 cause the relay 12 to drive the relay 6 via the transistor 11 which is a logic NOR. Further, the diodes 13 and 14 are arranged so that the respective timers 8 and 10 are not influenced by each other.

The ST position 4 is connected to the coil of the relay 6 by a line 16 via a diode 27,
Therefore, when the operation switch 2 is in the ST position 4, the relay 6 is activated regardless of the operation of the control circuit 7.
, and the glow plug 5 is energized.

To explain the operation of the first embodiment with the above configuration, when the operation switch 2 is connected to the ON position 3 to prepare for operation, the first timer 8 starts operating and its output terminal becomes H level and the diode 13 Transistor 11 is turned on via. Since the transistor 11 is a logic NOR, its collector is L.
level, the coil of the relay 12 is energized and the contacts are closed. As a result, the coil of the relay 6 is energized and its contacts are closed, so power is supplied from the line 15 to the glow plug 5 and heating begins.
A heating indicator lamp (not shown) lights up to notify the driver that the glow plug is being preheated.

The predetermined time preset in the first timer 8, that is, the time until the temperature of the glow plug 5 reaches a temperature at which the engine can be started (approximately 800°C), and also depends on the degree of cooling of the engine obtained by the sensor 9. After the varying time has elapsed, the first timer 8 ends its operation and its output goes to L level.

Therefore, the transistor 11 is turned off, its collector becomes H level, and the contacts of the relay 12 and the relay 6 are opened, so the power supply to the glow plug 5 is stopped, and the heating indicator lamp (not shown) is turned off, causing the driver to Announce that it is possible to start.

When the driver sets the operation switch 2 to ST position 4, power is supplied to the coil of the relay 6 via the line 16, so the contacts of the relay 6 are closed and the glow plug is energized, and the The starter motor rotates and the engine starts. When the driver confirms the start, releases the operation switch 2 from the ST position, and returns it to the ON position 3, the second timer 1 starts.
0 starts operating, its output becomes H level,
The same operation as that of the first timer 10 described above is repeated.

As mentioned above, the operating time of this second timer 10 is the time required from immediately after startup to the point where warm-up progresses halfway and black smoke is slightly emitted (this may differ depending on each engine). It is set by.

As described above, the first timer 8 and the second timer 1
0 is responsible for heating the glow plug 5 before and after startup, respectively, but once the operation of the first timer 8 is finished, the operation switch 2 is turned ON.
From position 3 to ST position 4, and from ST position 4 to ON
Even if it is switched to position 3, it is configured so that it will not start operating again as long as power continues to be supplied through the line 15.

FIG. 2 shows a second embodiment of the present invention, and the configurations numbered 1 to 16 in the figure are the same as the first embodiment, with the only difference being the input to the second timer 10. , the explanation of the configuration of this part will be omitted.

In the figure, 17 is a known vehicle alternator,
18 is also a known voltage regulator.

The alternating current generator 17 and the voltage regulator 18 are connected to the ON position 3 of the operating switch 2 by a line 19.

Now simply alternator 17 and voltage regulator 1
8 will be explained below. When operating switch 2 is connected to ON position 3, track 19 and relay contact 23
The field coil 24 is energized via the power source, and the preparation for power generation is completed. When the engine starts, the star-connected generator 17 generates alternating current power as the engine (that is, the generator) rotates, which is rectified by a group of diodes to become direct current, which charges the battery 1. At this time, the first relay coil 20 of the voltage regulator 18 is excited by the voltage at the N terminal from the neutral point of the star connection of the generator 17, but the engine rotation is low and the generator 1
When the generated voltage of 7 is low, the voltage of the N terminal is also low,
An electromagnetic force sufficient to switch the contact 21 from terminal a to terminal b is not generated. Therefore, contact 21 remains connected to terminal a. When the rotation of the engine increases and the voltage generated by the generator 17 increases, the voltage at the N terminal also increases, and the contact 21 switches from terminal a to terminal b. Accordingly, the relay coil 22 is excited, and the generated voltage of the generator 17 causes the contacts 23 to
e and d, the field coil 24 is energized in three stages: directly, via the resistor 25, and stopped, and the voltage generated by the generator 17 is controlled to a predetermined value.

The contact point 21 switches from terminal a to terminal b when the engine speed is usually about 400 to 500 rpm, depending on the magnitude of the electrical load applied to the battery 1. In other words, move the operation switch 2 from the ST position.
It almost matches the rotation speed when switching to the ON position. Therefore, in this embodiment, the voltage change at the contact point 21 of the voltage regulator 18 is detected by the second timer 1 via the line 26.
0 and used as the operation start signal for the second timer 10.

This line 26 does not need to be specially installed to implement the present invention. This is because there is normally a track from the contact point 21 for a charge warning lamp that notifies the driver of the charging state, so this track can be used.

The operation of the second embodiment with this configuration is as follows:
The operation up to the end of the operation of the timer 8 is the same as in the first embodiment described above, and when the engine starts and reaches approximately 400 revolutions, the relay 21 is switched and the H level is sent to the second timer 10 via the line 26. The second timer 10 starts operating upon application of the signal, and ends its operation after a predetermined period of time has elapsed. The operating time of the second timer 10 is set in the same manner as in the first embodiment.

In addition, in the above-mentioned first and second embodiments, the second
The operating time of the timer is set constant, but like the first timer 8, the operating time can be changed depending on the engine temperature obtained by the sensor 9, and the sensor 9 is not limited to detecting the engine water temperature. lubricating oil temperature,
Even more precise control can be achieved by detecting ambient temperature, etc.

Further, in the first and second embodiments, the transistor 11 has been described as a logical NOR, but it is also possible to change the arrangement of the transistor 11 and the relay 12 so that the transistor 11 is a logical OR.

As explained above, the present invention is configured so that the first timer preheats the glow plug before starting the engine, and even after the engine starts, the second timer energizes the glow plug until after the engine has completely exploded. In addition to effectively reducing black smoke emissions during driving,
It also has the effect of stabilizing engine rotation after startup, making it an extremely useful device in practice.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a first embodiment of the present invention, and FIG. 2 is a circuit diagram showing a second embodiment of the present invention. 2: Operation switch, 3: ON position, 4: ST position, 5: Glow plug, 6: Relay, 8: First timer, 9: Sensor, 10: Second timer, 1
7: Alternator, 18: Voltage regulator.

Claims (1)

[Scope of utility model registration request] a first timer that starts operating and operates for a predetermined time when the operating switch is switched from the OFF position to the ON position; and a first timer that is driven by the engine when the operating switch is switched from the ST position to the ON position. a second timer that starts operating when the generated voltage of the generator reaches a predetermined voltage and operates until at least after the engine has completely exploded; A glow plug preheating device for a diesel engine, characterized in that it is configured to apply electricity to the glow plug.