JPH027264Y2 - - Google Patents

Description

[Detailed explanation of the idea]

[Industrial Application Field] The present invention relates to a preheating control device for a glow plug installed in a combustion chamber of a diesel engine, and particularly relates to a glow plug that can preheat a glow plug with a simple configuration at low cost and economically. The present invention relates to a preheating control device. [Prior Art] A conventional glow plug preheating control device is disclosed in, for example, Japanese Unexamined Patent Publication No. 112428/1982, and will be explained according to the block wiring diagram of FIG. A glow plug temperature detection resistor (hereinafter referred to as sensing resistor) 2 for detecting the temperature is connected in series, and as a circuit for supplying electricity to this series circuit, a circuit is connected from the positive terminal of the battery 3 through the contact 4a of the relay 4. A first circuit that is directly energized and a second circuit that is energized from the positive terminal of the battery 3 through the contact 5a of the relay 5 and the glow plug temperature control resistor (hereinafter referred to as a dropping resistor) 6. We are prepared. The control circuit 7 receives an operation signal S1 indicating that the power is turned on, a glow plug temperature signal S2 detected by the sensing register 2, etc., and calculates the input signal to control the first circuit and the second circuit. Control signals S3 and S4 for switching are output to the coils 4b and 5b of the relays 4 and 5, respectively. In such a configuration, when a key switch (not shown) is set to the operating position, an operating signal S1 is input to the control circuit 7, an output signal S3 is output to the coil 4b of the relay 4, the contact 4a is closed, and the glow plug 1 is switched to the first It is energized by the circuit and heated rapidly (rapid preheating state). However, the first
If the circuit is energized, the maximum usable temperature of the glow plug 1 will be exceeded, so the temperature of the glow plug 1 is detected as a voltage by the sensing resistor 2, and the detected glow plug temperature signal S2 is
It is compared with the set value in the control circuit 7, and when the set value is exceeded, the signal S3 is stopped and the signal S4 is output, the contact 4a of the relay 4 is opened, the contact 5a of the relay 5 is closed, and the glow is started. Electricity is supplied to the plug 1 via the dropping resistor 6 (stable preheating state). In this way, the glow plug temperature was controlled so as not to exceed the maximum usable temperature (dropping method). However, in the conventional device as described above, the power consumption of the dropping resistor 6 is 100

[W] Because of the above, the shape of the dropping resistor 6 becomes quite large, and the surface temperature also rises considerably, so in recent vehicles where the engine room has become cramped due to measures against exhaust gas, etc. The installation location of the topping resistor 6 is extremely limited. Further, it is uneconomical to waste power in the dropping register 6. Therefore, as a device for controlling the temperature of the glow plug 1 without using the dropping resistor 6 during stable preheating, the second circuit connecting the relay 5 and the dropping resistor 6 in series in FIG. 1 is deleted. , a so-called chopping method has been proposed in which the coil 4b of the relay 4 is driven intermittently during stable preheating to suppress the average voltage applied to the glow plug 1 (Japanese Patent Application Laid-Open No. 1989-1999).
151739). However, in this method, relay 4 controls opening and closing of a large current, so if a relay similar to the above-mentioned dropping method is used, the life of the relay contact will be significantly shortened, so it is necessary to use a larger relay or a relay with improved contacts. It becomes necessary and expensive. In addition, since a large current is switched on and off, the voltage of the battery fluctuates rapidly, and if a headlight is used, the brightness changes as the relay opens and closes, causing discomfort to the driver and causing other electronic devices to malfunction. There is also fear. [Problem] The present invention was developed in view of the above-mentioned drawbacks of the conventional type, and its purpose is to achieve stable preheating without using a dropping resistor or without intermittent current flowing to the glow plug. To obtain a glow plug preheating control device which is simple in construction, does not waste power, and is inexpensive. [Structure of the invention] The invention includes rapid preheating means for rapidly heating a glow plug disposed in a combustion chamber of a diesel engine, and stable preheating means for maintaining the temperature of the glow plug at a set temperature. A glow plug preheating control device comprising: two batteries connected in series, and a first circuit that energizes the glow plug from a high voltage terminal H of the series-connected batteries through a contact point of a first relay; a second circuit that energizes the glow plug from an intermediate terminal M of the series-connected batteries through a contact of a second relay;
The present invention is characterized in that it includes means for sending a switching signal to the coil of the first relay and the coil of the second relay in order to selectively switch between the first circuit and the second circuit. [Embodiment] Hereinafter, the present invention will be described in detail with reference to an illustrated embodiment. FIG. 2 shows a block wiring diagram of an embodiment of the glow plug preheating control device according to the present invention, and the same components as in FIG. 1 are given the same reference numerals. The glow plug preheating control device has a glow plug 1 and a sensing resistor 2 for detecting the temperature of the glow plug 1 connected in series, and a 12 [V] battery 3 as a circuit for supplying current to this series circuit.
24 of battery 3 where a and 3b are connected in series
A first circuit that conducts electricity from the [V] terminal H through the contact 4a of the relay 4, and the 12 [V] battery 3a, 3.
A second circuit is provided in which electricity is supplied from the 12 [V] terminal M at the intermediate point of the series connection of the terminals b through the contact 5a of the relay 5. The control circuit 7 receives an operation signal S1 indicating that the power has been turned on, a glow plug temperature signal S2 detected by the sensing register 2, etc., and calculates the input signal to control the first circuit and the second circuit. Control signals S3 and S4 for switching are output to coils 4b and 5b of the relays 4 and 5, respectively. In such a configuration, the operations of the control circuit 7, relay 4, and relay 5 are similar to those of the conventional type (FIG. 1), but the control signal S3 is stopped and the control signal S
4 is output, contact 4a of relay 4 is opened,
When the contact 5a of the relay 5 is closed, the glow plug 1 is energized by the second circuit from the 12 [V] terminal M of the battery 3, and the voltage applied to the glow plug 1 is , 1/ during rapid preheating
2, the temperature of the glow plug 1 is controlled so as not to exceed the maximum usable temperature. [Effects] As detailed above, according to the present invention, an economical and inexpensive glow plug preheating control device with a simple configuration can be provided without using a dropping resistor or without intermittent driving of a relay. Obtainable. In particular, when this invention is applied to a diesel locomotive that uses two 12V batteries connected in series as a power source, there is no need for much modification and the invention can be implemented very easily. It also has the effect of

[Brief explanation of the drawing]

FIG. 1 is a block wiring diagram showing a conventional dropping type glow plug preheating control device, and FIG. 2 is a block wiring diagram of a glow plug preheating control device showing an embodiment of the present invention. 1... Glow plug, 2... Sensing register, 3... Battery, 3a, 3b... 12 [V] battery, 4, 5... Relay, 7... Control circuit, H
...24 [V] terminal, M...12 [V] terminal.

Claims (1)

[Scope of utility model registration request] A glow plug preheating control device comprising rapid preheating means for rapidly heating a glow plug disposed in a combustion chamber of a diesel engine and stable preheating means for maintaining the temperature of the glow plug at a set temperature, Two batteries connected in series,
The first terminal from the high voltage terminal H of the batteries connected in series.
a first circuit that energizes the glow plug via a contact of a relay; a second circuit that energizes the glow plug from an intermediate terminal M of the series-connected batteries via a contact of a second relay; A glow plug preheating control device comprising means for sending a switching signal to the coil of the first relay and the coil of the second relay in order to selectively switch between the first circuit and the second circuit. .