JPS6115258Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intake air heating device, and more particularly to the device which can perform preheating prior to starting an engine and post-heating after starting the engine.

In diesel engines, when the engine is cold, the intake air heating device is generally used to preheat the intake air prior to starting the engine. In some cases, even after the engine has been started, it is preferable to further operate the device to heat the intake air until the engine is properly warmed up. Particularly in engines that are equipped with an exhaust supercharger and have a low compression ratio, heat is essential after this.

However, in producing heat after this, there are various problems that must be solved. In other words, to achieve post-heating including pre-heating, a relatively large current is passed through the heater, so the operation of the intake air heating device must be kept to the minimum necessary to ensure its durability, and battery consumption must also be considered. Must be. Furthermore, while the starter motor is rotating, the voltage at the terminals of the battery decreases, but after the starter motor starts working, the voltage increases rapidly. This could cause the rated voltage to be exceeded and cause it to melt.

The present invention has been made with attention to these points, and it is an object of the present invention to provide an intake air heating device that can automatically perform appropriate afterheating as required.

An embodiment of the present invention shown in the drawings will be described below. In FIG. 1, 11 is a fuel tank, 12 is a fuel injection pump, 13 is a built-in feed pump 14 which is a filter, 15 and 16 are check valves, 20 is a solenoid valve, and 30 is attached to an intake pipe 17. In the intake air heater, the fuel sucked up by the feed pump 13 is sent to the gearbox of the injection pump 12 via the filter 14 and supplied to the engine from the injection pipe 18.
0 to the heater 40 of the intake air heater 30 from the conduit 19. A battery 51 is connected to the heater 40 and the solenoid valve 20 via a control circuit 50.
If fuel is supplied to the red-hot heater 40 via the electromagnetic valve 20, the fuel will burn and heat the intake air flowing through the intake pipe 17. It is possible.
Note that 10 in the figure is an overflow pipe.

As shown in FIG. 2, the control circuit 50 includes a base terminal B connected to the battery 51, a preheating terminal P,
A key switch 52 with a stop position T, an accessory terminal A, and a starting terminal S, and three relays 60, 7.
0,80, switch 6 controlled by the relay
1, 62, 63, 71, 81 and diode 53
It also includes a capacitor 56, a dropper 57, etc., and is also connected to a starter motor 90, an indicator 41 that displays the degree of redness of the heater 40, and a safety relay 91 that automatically cuts off the power to the starter motor 90 after the engine is started. ing.

That is, a capacitor 56 and a relay 60 are connected in parallel to the preheating terminal P, while a heater 40 is connected to the preheating terminal P via a switch 61, an indicator 41, and a switch 62.
It is connected to

Further, a heater 40 is connected to the starting terminal S via a diode 53, a dropper 57, an indicator 41, and the switch 62, and a switch 71,
The heater 40 is connected via a switch 62. Starter motor 90 is connected to battery 51 via switch 81. The solenoid valve 20 is operated via the switch 63 and the relays 70 and 8.
0 are connected to the starting terminal S via the safety relay 91.

In the intake air heating device of the present invention having the control circuit 50 having such a configuration, preheating, starting, and
After-heating is achieved.

First, before starting the engine, switch the key switch 52.
Connect base terminal B and preheating terminal P by operating . Then, at the same time as the capacitor 56 is charged, the current from the battery 51 flows to the heater relay 60, and the switches 61, 6 controlled by the relay 60 are activated.
2 and 63 are respectively turned on, current flows through the battery 51 - base terminal B - preheating terminal P - switch 61 - indicator 41 switch 62 - heater 40, and the heater of the intake air heater 30 becomes red hot.

The degree of red heat of this heater 40 is determined by an indicator 41 which has similar characteristics to this heater.
It is determined by the degree of redness.

After the heater 40 is sufficiently preheated, the key switch 52 is operated again to connect the base terminal B to the starting terminal S.

At this time, although the power to the heater relay 60 is temporarily cut off, the relay maintains its operating state due to the discharging action of the capacitor 56, and the switches 61, 62, and 63 each continue to be turned on. Thereafter, current flows through the starting terminal S, the diode 53, the dropper 57, the switch 61, and the relay 60, and the operation continues.

When base terminal B and starting terminal S are connected,
Starter relay 80 operates and switch 81 is turned on.
At the same time, the relay 70 also operates and the switch 71
Turn on. As a result, current flows through the battery 51, the switch 81, and the starter motor 90 to drive the engine, and at the same time, the dropper 57
A large current can be passed to the heater 40 through the starting terminal S-switch 71-switch 62 without going through the indicator 41. Furthermore, at the same time, current flows from the starting terminal S to the solenoid valve 20 via the switch 63, and the solenoid valve is opened. In this situation, since the engine is being driven by the motor and the fuel injection pump 12 is also rotating, the heater 4 of the intake air heater 30 is turning the fuel from the conduit 19 red hot.
Supply to 0.

Therefore, the fuel burns in the intake pipe 17, heating the intake air and assisting in starting the engine.

Safety relay 91 occurs when the engine starts rotating on its own.
works to stop the operation of relays 70 and 80,
Turn off switches 71 and 81. As a result, the starter motor 90 stops driving the engine, and the switch 71 to the heater 40 is turned off, so that current flows through the starting terminal S, the diode 53, the dropper 57, the indicator 41, and the switch 62, causing red heat. Although the conversion continues, the voltage becomes limited. In this state, the solenoid valve 20 is still open, and combustion for afterheating is maintained.

After-heating is achieved in this way. Then, when the engine starts to rotate stably, the key switch 52 is operated to switch the connection between the base terminal B and the starting terminal S to the connection with the accessory terminal A.
Then the relay 60 will stop operating and the switch 6 will stop.
1, 62, and 63 are turned off, power to the heater 40 and the solenoid valve 20 is cut off, and the post-heating ends. In this case, a sensor capable of determining the rotational state of the engine is interposed in the control circuit 50, and when the engine reaches stable rotation, the connection between the base terminal B and the starting terminal S is automatically connected to the accessory terminal A. It is also possible to switch the connection to

Further, in the present invention, when preheating and afterheating are not required, such as when restarting the engine after it has started, the operation of the intake air heater 30 can be kept stopped. That is, unless the base terminal B is connected to the preheating terminal P, the relay 60 will not operate, and therefore the switches 61, 62, and 63 will remain OFF, so the base terminal B is connected to the starting terminal for starting. Even if connected to S, the heater 40 and solenoid valve 20 will not operate, and the intake air heater 30 will not work unnecessarily.

As described above, according to the present invention, preheating can be followed by postheating, or can be removed as necessary, and the operation of the intake air heater 30 can be minimized to improve its durability. You can spread it out into a wide width. Furthermore, when the starter motor 90 rotates, a large current flows through it and the voltage at the terminals of the battery 51 drops.If the current is passed through the heater 40 through a resistor such as the dropper 57 or the indicator 41, the voltage drop is significant and the battery becomes red hot. However, in the present invention, the switch 71 is turned on and a large current is passed through the heater 40 without passing through these resistors, so that red-hot state can be maintained. Then, when the engine starts rotating on its own and the generator is activated and this voltage suddenly increases, the rated voltage of the heater 40 may be exceeded and it may be blown out. Above switch 7
1 is turned off with safety relay 91 and Droppa 5
Since the voltage is appropriately dropped in step 7 and then supplied to the heater 40, it is possible to prevent the voltage from being fused.

Note that since the relays 70 and 80 operate under the same conditions, it is also possible to use only the existing starter relay 80. This is achieved by wiring as shown by the dotted line in FIG. 2 and interposing the switch 82 therein.

Further, in this specification, an example of the intake air heater 30 in which fuel is supplied to the heater 40 and is burned in the intake pipe 17 has been described, but this is similar to a known glow plug. The present invention can also be applied to an intake air heater equipped with only an electric heater, and in this case, the circuit related to the solenoid valve 20 is naturally unnecessary.

Furthermore, since the switch 61 cuts off the power to the heater relay 60 when the base terminal B is connected to the starting terminal S when preheating is not required, it can be replaced with a diode. Similarly, since the diode 53 has a similar function, it can also be replaced with a switch.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing an outline of the intake air heating device according to the present invention, and FIG. 2 is a wiring diagram showing its control circuit. 20; Solenoid valve, 30; Intake heater, 40; Heater, 41; Indicator, 50; Control circuit, 5
2; Key switch, 57; Drotspa, 60,7
0, 80, 91; Lillet, 61, 62, 63, 7
1,81; switch.

Claims (1)

[Scope of utility model registration request] A key switch has a base terminal connected to the battery, a preheating terminal, and a starting terminal connected to the starter relay via a safety relay, and the base terminal is sequentially connected to both the preheating and starting terminals to turn on the heating oil. It consists of an intake heater that heats the inside of the intake pipe by igniting and burning it with a heater, a solenoid valve that supplies fuel to the heater, and a control circuit that controls the operation of the solenoid valve and the heater. A relay for operating the electromagnetic valve and the heater when the terminal is connected to the preheating contact, and a relay for operating the starter motor and the electromagnetic valve when the base terminal is connected to the starting terminal, and for weakening the heater after the engine starts. An intake air heating device consisting of a safety relay that emits a signal for activation and a safety relay that stops operation of the starter motor when the engine rotates.