JPS6023513Y2 - Diesel engine preheating device - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a preheating device for a diesel engine.

In a diesel engine, each pre-combustion chamber is provided with a glow plug in order to effectively start the engine even in low temperature conditions.

When the pre-combustion chamber is heated to a predetermined temperature by the glow plug, the glow plug stops energizing, but if the time from this stop time to the time when the engine starts is long,
The pre-combustion chamber cools down again, making it difficult to start the engine.

SUMMARY OF THE INVENTION An object of the present invention is to provide a preheating device that can effectively start an engine even when the time from when the precombustion chamber is heated to a predetermined temperature until the time when the engine is started is long.

Next, embodiments of the present invention will be described with reference to the drawings.

One end of the storage battery 1 is grounded, and the other end is connected to a base terminal 4 of a key switch 3 via a fusible link 2.

In addition to the base terminal 4, the key switch 3 includes an open (OFF) terminal 5, an accessory (ACC) terminal 6, and a start (-3T) terminal 7.
, and a contact 8.

As is well known, accessory terminal 6 is connected to an accessory such as a radio, and starting terminal 7 is connected to a starting motor.

When the key is in a position corresponding to the accessory terminal 6, the accessory terminal 6 is connected to the base terminal 4 via the contact 8, and when the key is in a position corresponding to the starting terminal 7, the accessory terminal 6 and the starting Terminal 7 is connected to base terminal 4 via contactor 8, and a predetermined voltage from storage battery 1 is applied to accessory terminal 6 and starting terminal 7.

The open terminal 5 is not connected to anything and is connected to the accessory terminal 6.
is connected via fuse 11 to a first timer circuit 13 of controller 12.

A thermistor 14 is attached to the engine water jacket and sends information regarding the coolant temperature to the first timer circuit 13.

The output of the first timer circuit 13 is sent to the amplifier circuit 15.

From the neutral terminal 17 of the alternator 16 driven by the engine, information as to whether the engine is running or not is sent to the inhibition circuit 21, the output of which is sent to the amplifier circuit 15.

The output of the amplifier circuit 15 is sent to a second timer circuit 22 and a pilot lamp 23 in the driver's cab.

The output terminal of the second timer circuit 22 is grounded via the coil 25 of the relay 24.

One end of the switch 26 of the relay 24 is connected to the fusible link 2, and the other end is connected via a heater resistor 31 to a glow plug 27 provided in each pre-combustion chamber.

The glow plug 27 is also connected to the fusible link 2 via a switch 33 of a relay 32.

The coil 34 of the relay 32 is grounded at one end and connected to the starting contact 7 at the other end.

The operation of this device will be explained with reference to FIG.

In FIG. 2, the horizontal axis indicates time t, and on the vertical axis, a high level indicates that the substrate is in an active state, and a low level indicates that the element is in an inactive state.

At the time, the contact 8 is moved by the driver,
When the terminals 4 and 6 are connected, a voltage is applied to the controller 12.

This voltage is sent to the first timer circuit 13, and the first timer circuit 13 puts the amplifier circuit 15 into operation from this time t1.

The operating output of the amplifier circuit 15 is sent to the pilot lamp 23 to light the pilot lamp 23, and also energizes the coil 25 via the second timer circuit 22.

The switch 26 is closed by the attraction force from the coil 25, so that the glow plug 27 is in a heating operation state.

The relationship between the engine coolant temperature P and the time T during which the first timer circuit 13 operates the amplifier circuit 15 is as shown in the graph of FIG.

At a time when a predetermined time T determined by the cooling water temperature has elapsed, the timer circuit 13 switches the amplifier circuit to an inactive state.

Therefore, the pilot lamp 23 in the driver's cab is turned off.

Even if the output of the first timer circuit 13 changes from active to inactive, the second timer circuit 22 still does not change its output and continues to energize the coil 25 of the relay 24.

Therefore, the glow plug 27 is maintained in the heating operation state even after the current time.

At time t3, when another predetermined time U has elapsed from time t2, the second timer circuit 22 switches the coil 25 from the energized state to the deenergized state.

Therefore, the heating operation of the glow plug 27 stops after that time.

When the driver detects that the pilot lamp 23 is off, the contact 8 is moved and the terminals 4 and 7 are connected.

During the period when terminal 4 is connected to terminal 7, coil 34 of relay 32 is energized, so switch 33 is closed.

Therefore, the glow plug 27 is supplied with power via the switch 33 and is in a heating operation state.

The contact 8 has a predetermined area, and during the period when terminals 4 and 7 are connected, terminal 4 is also connected to terminal 6, so accessory devices such as a radio will not stop during this period. do not have.

Further, when the driver's hand leaves the key switch 3, the contact 8 automatically leaves the terminal 7 and returns to the position of the terminal 6.

It is assumed that the starting terminal 7 is connected to the base terminal 4 at any time, including after time t2 when the pilot lamp 23 is turned off, the starting is successful, and the engine is in a state of rotation at a predetermined rotational speed or higher.

While the engine is rotating, the voltage at the neutral terminal 17 of the alternator 16 is maintained at a predetermined value or higher.

This voltage at the neutral terminal 17 is sensed by the inhibit circuit 21, which switches the respective outputs of the amplifier circuit 15 and the second timer circuit 22 into inactive.

Therefore, the pilot lamp 21 goes out, and
The heating operation of the glow plug 27 also stops.

As described above, according to the present invention, even after the pre-combustion chamber reaches a temperature at which the engine can be started, the glow plug 27 continues its heating operation for a predetermined period of time U, so that the engine can be started only after the pilot lamp 23 goes out. Even if there is a long time interval before starting, the engine can be started effectively.

According to the present invention, the inhibiting means is provided, and the inhibiting means is configured to control the first and second parts of the preheating timer (the first part is the lamp) when the engine rotational speed exceeds a predetermined value due to successful starting. The second part sets the glow plug activation time.

) to disable lamp display and glow plug energization.

If the preheating timer operates in the same way as it did during the initial start, the glow plug will operate even after the start, creating an extremely dangerous situation.However, this invention prohibits this and requires troublesome manual operation. Therefore, energization of the glow plug after startup is automatically prohibited, thereby reliably avoiding danger.

According to the present invention, the key switch 3 has separate accessory terminals 6 as preheating terminals and starting terminals 7 as starting terminals, so preheating and starting can be performed separately, and after preheating is completed, It is not necessary to start immediately, a predetermined degree of freedom regarding the starting operation time is secured, and when a predetermined voltage is applied to the starting terminal 7 for the starting operation, a predetermined preheating has already been performed. As a result, the beginning can be done quickly.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram showing an embodiment of the present invention, Fig. 2 is a diagram showing the operating state of the embodiment of Fig. 1, and Fig. 3 shows the relationship between the heating time of the pre-combustion chamber and the cooling water temperature. It is a graph. 3...Key switch, 6...Accessory terminal, 7...Start terminal, 12...Controller, 13...1st timer circuit, 21...
・Prohibition circuit, 22...Second timer circuit, 23
...Pilot lamp, 24, 32...
・Relay, 27...Glow plug.

Claims (1)

[Scope of utility model registration request] A switch having a preheating terminal and a starting terminal, a preheating timer that determines a predetermined time from the time when a predetermined voltage is applied to the preheating terminal, and a pump that is installed in the operator's cab and is energized in relation to the output of the preheating timer. and a glow plug for heating a precombustion chamber of the engine, which is energized when a predetermined voltage is applied to a starting terminal and is energized in relation to the output of a preheating timer to heat a precombustion chamber of the engine. , the preheat timer has a first portion defining a first predetermined period of time related to engine temperature and a second portion that is longer than the first predetermined period of time.
a second portion defining a predetermined period of time;
The fuel plug is energized for a second predetermined period of time, and when the engine speed exceeds a predetermined value, the first and second parts of the preheat timer are reset and the lamp is displayed. 1. A preheating device for a diesel engine, characterized in that a prohibition circuit is provided for prohibiting energization of a faulty plug.