JPS60178977A - Temperature controller for glow plug - Google Patents

Abstract

PURPOSE:To maintain the glow plug temperature at predetermined level by providing a power supply controller for controlling a relay switch for supplying/interrupting power to the glow plug while providing an after-glow timer in said controller. CONSTITUTION:A quick-heated glow plug 3 has temperature control function and power supply/interruption of which is controlled by a relay switch 4. Upon turning on of a key switch 1, a preglow timer 8 will function to supplypower to the glow plug 3 thus to perform preheating. While upon turning of key switch 1 to ST, capacitor C1 is discharged. Upon returning to ON, a glow relay 5 is turned on to perform after-glow. Consequently, the glow plug temperature can be maintained at proper level.

Description

[Detailed Description of the Invention] (Technical Field) Appropriate temperature control of a so-called glow plug for preheating used to facilitate starting of a diesel engine when it has cooled to a temperature lower than its starting temperature. The technical content described in this specification in connection with This paper proposes development results for reliably and advantageously protecting heating coils from overheating and burnout.

(Background technology) Glow plug energization control used to include a rapid heating relay and a stable heating relay to continue stable heating for as long as necessary even after the diesel engine started after rapid heating.
Although a control device including a resistor for current limiting has been used, the control circuit requires a relay, which increases the number of parts and increases costs.

In recent years, glow plugs for rapid heating have been developed by using a heating coil made of a material with a positive temperature coefficient of resistance, such as Ni wire, and by passing a large current immediately after energization to quickly raise the temperature, and then reducing the current as the temperature rises. Models that prevent overheating of glow plugs are beginning to be used, but if the glow plug is continuously energized, the temperature of the glow plug may rise too much and cause the heating coil to melt. Another attempt was made to use two energizing relays, one for rapid heating, and the other to limit the temperature of the glow plug to the temperature required to start the entire engine via a current limiting resistor after rapid heating. There were many mechanical parts, and the system was complicated and expensive. (Prior art and its problems) In order to further expand the overheating prevention by self-blading temperature control of the 6-globe ladder, the resistance temperature was used as a heating coil. A glow plug using two or more types of heat generating materials with different coefficients was disclosed in JP-A-54-109588,
Under the unavoidable fluctuations in battery voltage and other influences,
If you try to ensure the voltage characteristics that meet the requirements for preheating temperature and temperature during cranking, there is a risk of overheating during afterglow, and if you try to satisfy the afterglow conditions, the preheating time may become longer. Unfortunately, the specified temperature was not maintained during cranking.

(Objective of the invention) To easily ensure an appropriate glow plug temperature through each stage of glow plug preheating, cranking, and afterglow. r! l11 current limiting resistor,
As a system that does not require the use of control relays or the like, it is simple and highly reliable at low cost, and can maintain stable afterglow while maintaining the glow plug at a predetermined temperature during cranking without extending the preheating waiting time. It is an object of the present invention to provide a temperature control device.

(Structure of the Invention) The above object is advantageously achieved by a system having the following points as its main points.

This invention is a temperature control device for a rapid heating type glow plug that has a temperature control function and uses two or more types of heat generating materials with different resistance temperature coefficients as the heat generating coil of the glow plug, and is capable of intermittent electricity supply to the glow plug. The energization control device controls the temperature of the glow plug, and the energization control device has an afterglow timer that controls time depending on the voltage applied to the glow plug. It is a device.

The configuration of the present invention will be specifically explained below with reference to the drawings.

FIG. 1 shows a specific circuit configuration, and FIG. 2 shows an operation chart.

In the figure, 1 is a key switch, 2 is a battery, 8 is a rapid heating type glow plug with temperature control function, 4 is its energizing contact, and 5 is a glow relay.〇When key switch 1 is first turned on, the lamp timer is activated. 6 operates to cause the lamp 7 to light up for a predetermined period of time with the help of the NOT circuit NOT□, and the glow timer 8 also operates to close the glow relay 5 through the AND circuit AND2 and the OR circuit OR, thereby turning on the glow plug 8. Preheating is performed by energizing, and after a predetermined time has elapsed, the lamp 7 is turned off to notify completion of preheating.

Therefore, when the key switch 1 is set to ST, the glow relay 5 continues to close via the OR circuit oR1, and at the same time, the transistor Q2 is turned on via the resistor 8, and the charge of the capacitor C0 included in the afterglow timer circuit 9 is is discharged through the resistor R0°, and the reset state is maintained.

In this way, the engine completely explodes and the terminal of the regulator (not shown) becomes Hi, but when key switch 1 is turned back on, the output of the voltage comparator IC is changed to the AND circuit AN.
The glow relay 5 is turned on via D□ and the OR circuit OR1, and an actor glow is performed.

In this case, the afterglow time is controlled as follows depending on the voltage of the glow plug 8.

When the voltage is below the predetermined voltage, the capacitor C0 is charged by the constant voltage circuit 10 and only from the resistor R4, so for one hour afterglow, R,0□
The time is determined by the time constant.

When the specified voltage is exceeded, the glow voltage ■. is divided by resistors R0 and R8, and when the voltage becomes larger than the sum of the base voltage of the transistor Q and the base voltage of the transistor Q, the transistor Q turns on and charges the capacitor C0 via the diode D1. is performed to shorten the operating time of the afterglow timer 9. At this time, a constant voltage of (■2+vBE) is applied to the resistor R2, so each current of the resistors R□ and R is 1□,
Then, the tr current (I, - 2) flowing into the emitter of the transistor Q□ is one voltage ■. It is the value obtained by subtracting a constant value from the value proportional to
This current mostly passes through the diode D0 and the capacitor C
It is charged by the factory. 9. When the glow plug exceeds the specified voltage, the glow voltage ■. A current proportional to the value obtained by subtracting a predetermined voltage from the voltage flows into the capacitor C□, and the after-grossing time is shortened.

The glow plug 8 is maintained at about 900°C when the above-mentioned predetermined voltage is applied, and when a voltage exceeding the predetermined voltage is applied, the power corresponding to the excess voltage causes an excessive temperature rise in the glow plug 8. The operation time of the afterglow timer 9 is shortened by integrating them.

Next, FIG. 8 shows another embodiment in which the bri-glow timer 8 of FIG. 1 is also incorporated into the circuit of the after-glow timer 9' to simplify the structure. After starting, the regulator terminal becomes Hi, transistor Q is turned on, and capacitor C1 is charged only through resistor R. It operates as an afterglow timer for a longer period of time, and the glow voltage is instantaneous afterglow and flash. Control can be performed accordingly.

Moreover, if the signal from the water temperature sensor l as shown in FIG. 4 and the afterglow signal shown in FIG. 8 are processed by the AND circuit 1z, even more effective utilization can be achieved.

(Effects of the invention) Glow plugs with self-cutting temperature control function allow for preheating.
Through each stage after cranking and starting, an appropriate glow plug temperature can be ensured with a simple circuit configuration without requiring the use of current limiting resistors or control relays.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of the embodiment, Fig. 2 is an operation chart, Fig. 8 is a circuit diagram of another embodiment, and Fig. 4 is a circuit diagram showing the additional configuration of the main parts.
Rapid heating type glow plug with temperature control function 4... Relay switch 9.9'... Afterglow timer. Patent applicant: Nippon Tokushu Togyo Co., Ltd.

Claims (1)

[Claims] L A temperature control device for a rapid heating type glow plug having a temperature control function using two or more types of heat generating materials with different temperature coefficients of resistance as the heat generating coil of the glow plug, which controls the supply of electricity to the glow plug. It is equipped with one V-switch that turns on and off, and an energization control device that controls this relay switch, and this energization control device is characterized in that it has an afterglow timer that controls time depending on the voltage applied to the glow plaque. Glow plug temperature control device.