JPH0541249Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a protection device for an internal combustion engine that improves engine protection during warm-up operation.

[Prior Art] Conventionally, as a protection device for an internal combustion engine, as disclosed in Japanese Utility Model Application Publication No. 57-114137, for example, the voltage generated by an alternator, which has a correlation with the engine rotation speed, and the engine lubricating oil supply are controlled. A system has been proposed that detects the pressure and issues an alarm or stops the engine if there is an abnormality in either the generated voltage or the supplied voltage after a predetermined period of time has elapsed after the engine has started.

However, with conventional systems, the voltage generated by the alternator is used as a signal to detect when the engine starts, so if the fan belt breaks and overheats, the alternator will not rotate and no detection signal will be obtained, causing the engine to stop. I couldn't let it go. Additionally, when an alarm is issued in the event of an abnormality, the alarm lamp will turn off once the engine returns to normal, so even if you try to check the engine a while after it has stopped, you will not be able to find out why the engine stopped. It was difficult.

Furthermore, if the engine reaches the rated rotation instantaneously at startup, checking after a certain period of time will not be enough.
Particularly at low temperatures where there is a delay in the rise of oil pressure, it has not been possible to deal with engine seizure caused by the engine reaching its rated rotation before the oil pressure has sufficiently risen.

On the other hand, various engine protection devices other than those described above have been proposed. For example, some engines automatically turn off the starter when the engine speed reaches a certain set speed when starting the engine.
This does not directly detect the engine speed, but rather looks at the voltage generated by the alternator, and turns off the starter based on this value.
When the fan belt slips or when the alternator is cold and when the alternator is warmed up, the startup performance differs.
The OFF timing accuracy was poor. Furthermore, in systems that stop the engine when oil pressure drops or overheats, etc., the engine stops instantly even if a temporary abnormal stop signal is generated, which may cause malfunctions.

On the other hand, these various engine protection devices are
Normally, it is not manufactured as a single unit, but is manufactured individually, and these parts are connected with a harness to be assembled as a protective device with multiple functions.However, since each part is connected with a harness, reliability is Not only was this inferior, but there was also the problem that parts were made by different manufacturers, and once a malfunction occurred in a combination, it was difficult to determine which part was defective.

[Problems to be solved by the invention] As mentioned above, the conventional system that checks the voltage generated by the alternator and the engine lubricating oil supply pressure after a predetermined period of time has passed after the engine has started, is not suitable for low-temperature systems where there is a delay in the rise of oil pressure. However, there was a problem in that it was not possible to effectively prevent the engine from seizing up due to instantaneous reaching of the rated rotation upon starting, resulting in a lack of reliability.

[Means for Solving the Problems] The internal combustion engine protection device of the present invention turns on the power and starts the starter using a key switch, and when the cooling water temperature is below a predetermined temperature, a forced idling operation is performed using a slow-down solenoid. In a protection device for an internal combustion engine in which a A circuit that includes a starter safety relay that drives the starter when the key switch is in the starting position, and that issues a complete explosion signal when the engine speed exceeds a predetermined value, and a circuit that disconnects the starter safety relay based on this complete explosion signal. and a circuit that returns the fuel cut solenoid to a non-operating position when any of the sensors that detect an abnormality in water temperature, oil pressure, air compressor discharge temperature, or fuel amount is activated for a predetermined delay time, and the circuit that returns the fuel cut solenoid to a non-operating position. The circuit includes a circuit that cancels the abnormality detection function for a while after the signal is output, and a circuit that drives the slow-down solenoid for a predetermined period of time after the complete explosion signal is output when the cooling water temperature is below a predetermined temperature. The circuit is integrated into the controller and is further provided with a switch for forcibly operating the slow-down solenoid.

Here, the predetermined temperature refers to a relatively high temperature at which the delay in rising of the oil pressure becomes small.

[Operation] When the power is turned on using the key switch, the fuel cut solenoid is attracted to the operating position and held at that position. If the fuel cut solenoid is not in the activated position, fuel will be cut off and the starter will not be activated. The starter is not activated simply by placing the key switch in the start position; the starter is activated only after the fuel cut solenoid is drawn into the operating position. This prevents the battery voltage from decreasing due to simultaneous operation of the fuel cut solenoid and starter.

When the starter is activated and the engine speed detected by the rotary pickup exceeds a predetermined value, the complete explosion circuit issues a signal. Since the rotary pickup directly detects the engine speed, it can accurately detect the engine speed without being affected by the operation of the fan belt or alternator. The signal from the complete explosion circuit disconnects the starter and prevents it from re-entering.

The functions of various sensors that detect abnormalities in water temperature, oil pressure, air compressor discharge temperature, fuel amount, etc. are canceled for a while after the complete explosion signal rises. Since the rise of oil pressure is delayed when the engine is started, the fuel cut solenoid is prevented from being erroneously returned to the non-operating position.

If various sensors detect an abnormality some time after the complete explosion signal rises, the fuel cut solenoid is returned to the non-operating position and the engine is stopped.

When the warm-up water temperature sensor indicates that the cooling water temperature is less than a predetermined temperature and the predetermined time has elapsed since the rise of the complete explosion signal, the slow-down solenoid returns the governor lever to the idling position. As a result, if the temperature is low when the engine is started, the engine will run at idling speed, thereby preventing the engine from seizing due to a delay in the rise of oil pressure. When the coolant temperature reaches a predetermined temperature or higher, the governor lever is returned to the rated operating position, and the engine is brought into rated operation. Furthermore, if a predetermined time period has elapsed since the rise of the complete explosion signal, the rated operation will begin even if the cooling water temperature has not reached the predetermined temperature.

[Example] An example of the present invention will be described in detail based on FIGS. 2 and 3.

FIG. 2 is a flowchart of an example of the internal combustion engine protection device of the present invention, that is, an engine protection system incorporating a warm-up slowdown function. It also has the basic functions of an external activation signal.

FIG. 3 shows an example of a circuit configuration embodying the system flow shown in FIG.
It consists of an abnormality display panel 13, an actuator group 14, a constantly energized fuel cut solenoid (hereinafter simply referred to as a fuel cut solenoid) 15, a slowdown solenoid 16, a starter 17, and the like. Since each of the above-mentioned functions is integrated into this system, there is no need to connect the parts with a harness, and the reliability is high.This circuit has the functions (1) to (13) described below. .

(1) Power ON When the key switch 10 is turned from OFF to ON, the output of the non-inverting gate 20 becomes "L", so the fuel cut solenoid relay 21 is immediately turned on, the fuel cut solenoid 15 is activated, and the fuel cut solenoid lever is activated. Rotate 18 to the RUN position.

(2) Lamp burnout check When key switch 10 is turned from OFF to ON,
At the ON signal, the abnormality display panel 1 passes through the one-shot multivibrator 22 that generates a 1 second pulse.
Since the abnormality indicator lamp 23 of No. 3 is turned on, the abnormality indicator lamp 23 is turned on for 1.0 seconds. This lamp 23 is a master lamp for indicating an abnormality, and by lighting this lamp, it is possible to confirm that a circuit bulb is burnt out.

(3) Starter operation One end of the relay winding of the starter safety relay 24 that drives the starter 17 is connected to the key switch 10.
The other end is connected to the connection point between the contact 15a of the fuel cut solenoid 15 and the suction coil 15b, respectively. The contact point 15a of the fuel cut solenoid 15 is completely closed when the fuel cut solenoid 15 shifts from suction to holding.
Turns OFF when activated.

Therefore, simply turn on key switch 10→
If you only set it to ST, the starter 17 will not turn on, and the fuel cut solenoid 15 will turn on and its contact 15a will turn off, causing the contact 15a and the suction coil 15 to turn on.
The voltage at the connection point with b decreases (earth level),
The starter 17 starts only when the starter safety relay 24 turns ON. That is, after detecting that the fuel cut solenoid 15 is turned on, the starter 17 is turned on.
Turn on. This confirmation can be done, for example, by pulling out the rod 15c of the fuel cut solenoid 15 and holding it in place while switching the key switch 10 to the ST position.
This becomes possible when the starter 17 is turned on when the rod 15c is sucked by releasing the hand from the rod 15c.

The reason why the fuel cut solenoid 15 is operated first and then the starter 17 is operated at the time of starting is because if the fuel cut solenoid 15 and the starter 17 are operated at the same time, the voltage drop in the battery B will be large. 15 may return, the solenoid 15 is attracted once with a large current, held with a small holding current, and then the starter 17 is turned to reduce the voltage drop mentioned above. This is to prevent malfunction of 15.

(4) Engine complete explosion detection rotation speed The rotation speed detected by the rotary pickup 25 is connected to the other end of the starter safety relay 24 mentioned above.
A complete explosion circuit 26 which outputs an "H" signal when the speed reaches 900 rpm (or 500 rpm) is connected via an OR gate 27. The rotation pick-up 25 is a tacho sensor that directly detects the engine speed.
Unlike methods that indirectly detect the engine speed from the voltage generated by the alternator, this method is very accurate, and detection will not become inaccurate or impossible due to fan belt slip or fan belt breakage.

This will increase the engine speed to 900rpm (or
500 rpm), the starter 17 is automatically disconnected even if the key switch 10 is in the ST position.

(5) Start of operation of the hour meter By connecting the complete explosion circuit 26 to the hour meter 28 via the gate 29, the starter 1
At the same time as 7 is automatically disconnected, the hour meter operation circuit is turned on.

(6) Prevention of starter re-jumping When the engine is running, the output signal of the complete explosion circuit 26 becomes "H" and the other end of the starter safety relay 24 is always "H", so set the key switch 10 to the start position ST again. Even if one end of the starter safety relay 24 is set to "H", the starter safety relay 24 does not turn on, so the starter 17 does not operate.

(7) Time delay when oil pressure rises The gate 34 is connected to various sensor signals obtained from the abnormality water temperature sensor 30, oil pressure sensor 31, air compressor discharge temperature sensor 32, and fuel amount sensor 33.
37, and by applying the output signal of the complete explosion circuit 26 to the gates 34 to 37 with a delay of 5 seconds by the delay circuit 40, the gates 34 to 37 are closed for 5 seconds after the automatic disconnection of the starter 17, and each sensor is Cancel the function. This is to eliminate false detection by cutting off sensor information during the delay in the rise of oil pressure when starting the engine.

(8) Engine warm-up performance This is the function that is the gist of this invention.

The control end of the relay winding of the slow-down solenoid relay 50 that drives the slow-down solenoid 16 and the warm-up indicator lamp 51 are connected to a one-shot circuit that is activated by the "H" signal of the complete explosion circuit 26 and generates a 50-second pulse. It becomes "H" when both the output of the Yotsuto multivibrator 38 and the output of the gate 45, which inverts the output of the warm-up water temperature sensor 39, which turns on when the temperature is below a predetermined temperature t°C and turns off when it is above t°C, are "H". gate 4
6 and gates 47 and 48 which invert this output, respectively.

Therefore, when the warm-up water temperature sensor 39 is ON, the engine is slowed down for 50 seconds after the engine has completely exploded, and the warm-up indicator lamp 51 is turned on.

Note that slowing down is also possible by manual operation of the external switch 52.

(9) Increase in water temperature For example, when the abnormality water temperature sensor 30, which turns on when the set temperature is less than 110°C and turns off when it is over 110°C, turns off, the delay circuit 41 turns on the fuel cut solenoid relay 21 after a delay of less than 1 second, for example, 0.6 seconds. OFF,
The fuel cut solenoid 15 is deactivated to stop the engine, and the water temperature abnormality indicator lamp 60 is turned on. This state is maintained by latch circuits 70 and 71 unless the key switch 10 is turned off.
The same holds true for the following (10) to (12).

(10) Oil pressure decrease For example, if the set oil pressure exceeds 1Kg/ ^cm2 , it will turn on and 1
The oil pressure sensor 31 turns off when the pressure falls below Kg/ ^cm2 .
When OFF is activated, after a 1.0 second delay in the delay circuit 42,
Fuel cut solenoid 15 in the same way as in (9)
is deactivated, the engine is stopped, and the oil pressure abnormality indicator lamp 61 lights up.

(11) Rise in discharge air temperature When the discharge air temperature sensor 32 of the air compressor, which turns on when it is less than x℃ and turns off when it exceeds it, turns off, the delay circuit 43 deactivates the fuel cut solenoid 15 after 0.5 seconds. The engine is stopped and the discharge air temperature abnormality indicator lamp 62 lights up.

(12) Decrease in fuel amount When the fuel amount sensor 33, which turns on when it exceeds the set amount z and turns off when it is below it, turns off, the fuel cut solenoid 15 becomes inactive after a 5-second delay in the delay circuit 44, and the engine stops. As a result, the fuel abnormality indicator lamp 63 lights up.

(13) Engine operation display (overrun) When the rotation speed detected by the rotation pick-up 25 is below the set rotation speed Ne, it becomes “L”, and when it exceeds Ne, it becomes “H”. The “H” signal from the operation circuit 55 is used for overrun. By turning on the relay 56, it is displayed that the engine has reached the set rotation speed. Note that the output of this circuit 55 also makes it possible to stop the engine when the engine is overspeeded.

As described above, according to the above embodiment, the signal for detecting the starting of the engine or the engine speed is not the voltage generated by the alternator.
Since the rotation pick-up signal is used, it is possible to automatically stop the engine even if the fan belt breaks and overheats, and the starter can also be automatically stopped when the engine reaches a certain set rotation when starting the engine.
The accuracy of the OFF function is also improved, and the reliability of the device can be improved. Furthermore, when the engine reaches overspeed, the rotation is detected by the rotation pickup, so it is easier to issue a signal than in the past.

In addition, since the information obtained from each sensor 30 to 33 is latched by the latch circuits 71 to 74, the lighting of the warning lamp at the time of an abnormal stop is self-maintained, and even if the engine returns to an abnormal state, the engine will not stop. You can easily find out the cause. Since it is combined with a constantly energized solenoid and various normally-on sensors, it has a fail-safe function and further improves reliability.

Furthermore, in the past, when an abnormality occurred, the engine was stopped instantaneously, which could cause malfunctions, but delay circuits 40 to 44 are provided, and if the abnormal stop signal is not continuously input for a certain period of time, the engine will stop. Since the engine is not stopped, the engine can be stopped with certainty.

[Effects of the invention] In summary, according to the invention, when the cooling water temperature is low, slowing down is performed until the temperature rises to a predetermined temperature, so it is possible to effectively avoid engine seizure caused by a delay in the rise of oil pressure at low temperatures. , which has the excellent effect of improving reliability.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a protection device for an internal combustion engine according to the present invention, Fig. 2 is a flowchart of the entire system incorporating an embodiment of the protection device of the present invention, and Fig. 3 is a system flowchart shown in Fig. 2. FIG. 2 is a detailed diagram of a circuit configuration that implements. In the figure, 1 is a governor lever, 2 is a slow-down solenoid, 3 is a sensor, 4 is a control section, and 5 is a drive section.

Claims (1)

[Scope of utility model registration request] In a protection device for an internal combustion engine, a key switch is used to turn on the power and start the starter, and forced idling is performed using a slow-down solenoid when the cooling water temperature is below a predetermined temperature. a contact that opens when the fuel cut solenoid is drawn into the operating position, and a starter safety relay that drives the starter when the contact is opened and the key switch is in the starting position, A circuit that issues a complete explosion signal when the engine speed exceeds a predetermined value, a circuit that disconnects the starter safety relay based on this complete explosion signal, and a circuit that detects abnormalities in water temperature, oil pressure, air compressor discharge temperature, and fuel amount. A circuit that returns the fuel cut solenoid to a non-operating position when one of the sensors continues to operate for a predetermined delay time, a circuit that cancels the abnormality detection function for a while after the complete explosion signal is issued, and a cooling water circuit. and a circuit that drives the slow-down solenoid for a predetermined period of time after the complete explosion signal is issued when the temperature is below a predetermined temperature, and also incorporates each of the circuits described above into the controller, and further includes a switch that forcibly operates the slow-down solenoid. A protection device for an internal combustion engine, characterized in that: