JPH01257764A - Auxiliary device for starting of direct injection type diesel engine - Google Patents

Abstract

PURPOSE:To prevent the overheating of glow plugs and the consumption of a storage battery by determining the pre-heating time of the glow pulse in accordance with the cooling water temperature of an engine and, further determining an after-glow time after completing explosion equally in accordance with the cooling water temperature. CONSTITUTION:When a cooling water temperature detected by a water-temperature sensor S is below a defined temperature, the operating times of the timers 12, 14 of a lamp and a glow plug are determined in accordance with the cooling water temperature and, by setting a key switch SW to ON, a lamp PL is turned on while electrifying glow plugs G via an indicating portion 13. As the lamp PL is turned off while setting the key switch SW to an ST position, an engine is started and, at this time, the glow plugs G are electrified while restarting the glow-plug timer 14 to carry out after-glow for the set time of the timer 14 after the SW is returned to the ON position, by an electrification extending means 16. Also, if the cooling water temperature is above the defined temperature, no electrification is carried out at all. Thereby, highly efficient pre-heating can be performed preventing the overheating of the glow plugs and the consumption of a storage battery.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a starting assist device for a direct injection diesel engine.

[Prior Art] In a diesel engine that does not have a sub-combustion chamber, in order to stabilize the rotation of the engine in cold weather, when the temperature drops below a predetermined temperature, before starting the engine, a control such as that shown in Fig. 7 is carried out. The circuit 20 energizes the glow plug G through relays R and I for a predetermined time determined by a timer 22 equipped with a thermoswitch 21 that opens the circuit when the temperature drops below a predetermined temperature, and cranks the engine. The timer 22 is reset at the same time, and afterglow is performed for a predetermined period of time even after the engine has completely exploded. The thermoswitch 21 is normally set at a predetermined temperature of about 0°C.

[Problems to be Solved by the Invention] However, in such a control circuit 20, the thermoswitch 21 operates in exactly the same way whether the cooling water temperature is around a predetermined temperature or in extremely cold conditions that are even lower than that. Therefore, the energization time of the glow plug G set by the timer 22 must be set so that the durability of the glow plug G is not impaired due to energization when the temperature is relatively high. Therefore, in extremely cold weather, there is a problem in that the time for energizing the glow plug G for afterglow, etc. is insufficient, and it is difficult to stabilize the rotation of the engine after it is started.

SUMMARY OF THE INVENTION An object of the present invention is to provide a starting assist device for a diesel engine that can efficiently energize a glow plug G with a simple configuration.

[Means for Solving Problem R] The present invention provides a self-control glow plug provided in a combustion chamber of an engine, a relay for energizing the glow plug, and a water temperature sensor for detecting a cooling water temperature of the engine. a sensor, a water temperature signal generating means for generating a voltage corresponding to the water temperature detected by the water temperature sensor, and the water temperature signal generating means starts operating when a key switch is turned on and is determined according to the output voltage of the water temperature signal generating means. a first timer that operates for a first time;
a second timer that starts operating when the key switch is turned on, is determined according to the output voltage of the water temperature signal generator, and is longer than the first time; a second timer that operates for a time; energizing means that drives the relay to energize the glow plug while the second timer is in operation; and energization extension means for restarting the glow plug and energizing the claw plug by the energizing means, and energizing for stopping the energizing of the glow plug by the energizing means when the water temperature detected by the water temperature sensor exceeds a predetermined temperature. Adopt technical measures consisting of stopping means.

In the present invention, when the engine cooling water temperature is below a predetermined temperature, the operating time of the first timer and the second timer is determined according to the engine cooling water temperature, and the key switch is turned on. Then, a display is displayed and the glow plugs are energized according to the respective activation times. When the display ends, the engine is started by turning the key switch to the starter motor energizing position, and at this time, the glow plug is energized by the energizing extension means and the second timer is restarted. Therefore, after the key switch is returned to the on position, afterglow is performed for a further operating time of the second timer.

On the other hand, when the engine cooling water temperature is equal to or higher than the predetermined temperature, no current is applied to the glow plug.

[Effects of the Invention] In the present invention, the preheating time for the glow plug is determined according to the cooling water temperature of the engine, and the afterclaw time after a complete explosion is also determined according to the cooling water temperature. Even at times, sufficient current can be applied. In addition, if the cooling water temperature is not low, the claw plug is energized or stopped, and the energization time is set short, so that it is not energized more than necessary, preventing overheating of the glow plug and battery consumption. This can be prevented, and efficient energization can be performed.

[Example] Next, the present invention will be explained based on examples.

The starting assist device for the direct injection day cell engine shown in Fig. 1 consists of a key switch SW that controls the start and stop of the engine, a glow plug G provided in the day cell engine, and a glow plug G that controls engine cooling water temperature. A water temperature sensor S that indicates a resistance value that changes depending on the temperature, a relay RL for energizing the glow plug G, a lamp PL that indicates completion of preheating, and a lamp PL and a relay RL based on the temperature detected by the water temperature sensor S.
The control circuit 10 is operated by a battery B installed in the vehicle.

The key switch SW is OFF, ON, and ST; θ
The glow plug G is energized in the ON position, and the engine cracks in the ST position.

Glow Plug G is made by connecting in series a main heating element made of F'e-Cl-alloy, whose resistance value hardly changes as temperature rises, and a control heating element made of iron, which shows a large resistance value change with temperature rise. It is housed in a well-known tube, and as shown in FIG. 2, the surface temperature of the duplex is self-controlled over time to a constant temperature corresponding to the applied voltage.

The water temperature sensor S detects the cooling water temperature of the diesel engine using a thermistor whose resistance value decreases as the temperature rises, and is a constant voltage power supply divided by a resistor R1 connected in series. The applied voltage from section 18 is output as detection voltage Va.

The control circuit 10 includes a water temperature signal generator 11 and a lamp timer 12.
, a display section 13, a glow plug timer 14, a claw plug energizing section 15, an energizing extension section 16, an energizing stop section 17, and a constant voltage power supply section 18.

The water temperature signal generating section 11 receives the voltage V applied by the constant voltage power supply section 18.
a divided voltage vb divided by resistors R2 and R3,
This is a part that differentially amplifies the voltage difference with the detection voltage Va input through the resistor R4 by the operational amplifier OP1 and outputs it as the water temperature signal Vc.The higher the detected cooling water temperature, the higher the voltage of the water temperature signal Vc is output. .

The lamp timer 12 is for measuring the time until the glow plug G is preheated to a temperature suitable for starting the engine, and uses the operational amplifier OP2 as a comparator to
The potential at the connection point P1 between 5 and capacitor C1 is resistor R6,
Time ta until the voltage becomes higher than the divided voltage Vd due to R57
Only outputs high level. Here, the capacitor C1 is charged according to the water temperature signal Vc of the water temperature signal generating section 11 via the resistor R8 and the timer FD1.
The higher the cooling water temperature, the faster the battery is charged, so the operating time of the lamp timer 2 becomes shorter as the cooling water temperature increases.

In this example, as shown in Fig. 3, from -20°C to +5°
In the range to
It operates for a fixed period of seconds.

The display unit 13 is a circuit for informing the driver of the preheating state by the glow plug G, and the high level output of the lamp timer 12 is transmitted through the resistor R9 from 1 to the transistor R1.
When input to , 1~ransistor 1'R1 turns on,
Lamp 1)■ via diode D2 and resistor R)0
When the lamp 5 is energized, it lights up, and when the output of the lamp timer 12 becomes low level, it goes out.

The glow plug timer 14 is an erasing means for determining the energization time of the glow plug G, and similarly to the lamp timer 12, it uses the operational amplifier OP3 as a comparator and controls the resistance R.
The potential at the connection point P2 between 11 and the capacitor C2 is the resistor R1.
2. The capacitor C2 outputs a high level for the time tb until it becomes higher than the divided voltage Ve by R'13, and the capacitor C2 responds to the water temperature signal VC of the water temperature signal generator 11 via the resistors R1 and 4 and the diode D3. In the present embodiment, as shown in FIG.
60 seconds and 15 seconds below -20°C and above +0°C, respectively.
It operates for a fixed time of seconds.

The claw plug energizing section 15 connects the relay RL and the relay RL.
Transistor TR2 for conducting electricity and transistor 1 for switching
When the output of the glow plug timer 14 inputted through the resistor R15 is at a high level, or by a signal from the energizing extension section 16 described below, the relay RL is driven and the claw plug G is energize.

When the key switch SW is set to the ST position, the energizing extension section 16 connects the glow plug energizing section 15 to the diode D5 and the resistor R17 using the power supply voltage of the battery B or the voltage f applied to the diode D4 via the resistor R16. At the same time, the transistor TR4 discharges the charge in the capacitor C2 and resets the glow plug timer 14. Further, the capacitor C1 is forcibly charged via the diode D6 and the resistor R18 to time-up the lamp timer]2.

The energization stop unit 17 is a circuit for stopping energization to the claw plug G when the cooling water temperature is higher than a predetermined temperature of 5° C., and converts the voltage Va detected by the water temperature sensor S to the operational amplifier OP.
4, the detection voltage Va is resistor R19 and J: R20.
When the voltage is lower than the divided voltage Vg, the operational amplifier OP4 outputs a high level. This signal turns on the transistor TR5, and the transistor]
In order to bring the input voltage of R3 to a low level, both of the single-voltage resistors R3 and R2 are turned off, and the claw plug G is not energized by the relays R and L.

The constant voltage power supply section 18 stabilizes the voltage supplied from the battery B to particularly stabilize the operation of each operational amplifier.

Next, the operation of the diesel engine starting assist device of this embodiment will be explained.

(B) When the cooling water temperature is less than 5℃, the user turns the key switch SW from O to F at time to.
When placed in the position, the lamp timer 12 and the claw plug timer 14 each start operating 7, and as shown by the solid line in FIG. 5, the lamp PL is lit and the claw plug G is energized by the relay RI-. At this time,
The operating time of each timer is ta, depending on the cooling water temperature T.
(i~.6 seconds) and time tb (1.5 to 60 seconds), respectively.

When time 1, a has elapsed, lamp I-' l- goes out;
Accordingly, at time t1, the driver turns the key switch sw to S.
When set to T position, the starter motor rotates and cranks the engine. At this time, the claw plug energizing part 15
The claw plug G is energized by the energizing extension section 1G regardless of the output of the glow plug timer] 4, and the claw plug timer 14 is placed in the reset I state by a signal from the energizing extension section 16.

At time t2, the engine has completely exploded and the key switch SW is turned on.
When the position is returned to the position δ, the claw rack timer 14 starts operating again for a time t l) from this time t2, and the claw rack passage section 15 responds accordingly so that -11= time t b elapses. The glow plug G continues to be energized until time t3 to perform afterglow.

At this time, the temperature of the glow plug G is maintained at a high temperature by energization until times 1 and 3, as shown by the solid line in FIG.

Note that if the driver does not perform a cranking operation at time t1, relays R,
1, energizes the glow plug G from time 10 until time 1 and 3 when time tb has elapsed, and then stops energizing it;
The temperature of the glow plug G also decreases rapidly after times 1 and 3 accordingly.

(b) When the cooling water temperature is 5°C or higher, when the key switch SW is turned to the ON position at times 1 and 0,
As shown in FIG. 6, the lamp PL lights up for a minimum time of 1 second at time a, and then goes out. On the other hand, since the glow plug G is energized or stopped by the energization stop portion 17, it is not cut-through type. When the driver turns the key switch SW to the ST position and cranks the engine at an arbitrary timing, the engine completely explodes.

According to the present invention, with a simple configuration,
Efficient preheating can be performed. Further, when the temperature is high and preheating is not necessary, the glow plug is not energized, so overheating of the glow plug and battery consumption can be prevented. Furthermore, since the afterclaw time after a complete explosion is determined based on the cooling water temperature, the rotational stability of the engine after a complete explosion can be ensured even in extremely cold weather.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a starting assist device for a direct injection diesel engine according to an embodiment of the present invention, Fig. 2 is a time chart showing the temperature characteristics of the claw plug of this embodiment, and Fig. 3 is a lamp timer of this embodiment. Figure 4 is a characteristic diagram showing the operating time characteristics of the crawler timer of this embodiment as a function of cooling water temperature. Figures 5 and 6 are of the direct injection diesel engine of this embodiment. A time chart to explain the operation of the engine starting aid device, Figure 7 is a starting aid for a conventional direct injection diesel engine! It is a block diagram which does not show the structure of A position. In the figure, G・・Claw plug, S・・Water temperature sensor, Pl−
R, I-relay, 11.Water temperature signal generation section (water temperature signal generation means), 12.Lamp timer (first timer), 1B..Display section (display means), 14..
Claw plaque timer (second timer), 15. Claw plaque energizing part (energizing means), 16... energizing extension part (energizing extension means), 17. Energizing stop part (energizing stopping means).

Claims (1)

[Scope of Claims] 1) A self-control glow plug provided in a combustion chamber of an engine, a relay for energizing the glow plug, a water temperature sensor for detecting a cooling water temperature of the engine, and the water temperature sensor. a water temperature signal generating means that generates a voltage according to the water temperature detected by the water temperature signal generating means; the water temperature signal generating means starts operating when the key switch is turned on and operates for a first time determined according to the output voltage of the water temperature signal generating means; a first timer; display means for displaying when the first timer is in operation; the display means starts operation when the key switch is turned on, and is determined according to the output voltage of the water temperature signal generation means; 1st
a second timer that operates for a second time period that is longer than the period of time; energizing means that drives the relay and energizes the glow plug while the second timer is operating; and placing the key switch in the starter motor energizing position. energizing extension means for restarting the second timer and energizing the glow plug by the energizing means; A starting assist device for a direct injection diesel engine, comprising: an energization stopping means for stopping energization to a plug;