JPS60135622A - Cooling-water detecting apparatus for water-cooled engine - Google Patents

Abstract

PURPOSE:To prevent overheating of a water-cooled engine, by providing a cooling-water detecting means for giving an alarm when there is no cooling water, and controlling the engine speed to keep it lower than a predetermined value when the engine speed is higher than a predetermined value and there is no cooling water. CONSTITUTION:A cooling-water sensor 22 is provided in a cooling-water passage formed in the cylinder head or other part of a water-cooled engine. When there is no cooling water in the engine, the resistance between the sensor 22 and the earth becomes infinite and a transistor Tr1 is turned ON for giving an alarm from a buzzer 62. Further, when the engine speed is higher than a predetermined value, an engine-speed detecting circuit 56 functions to lower the engine speed by causing discharge of a capacitor 44 of an ignition circuit 38 and stopping emission of spark by an ignition plug 10.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a cooling water detection device for a water-cooled engine, and in particular, detects the presence or absence of cooling water and issues an alarm when there is no cooling water and also detects the engine speed. The present invention relates to a cooling water detection device for a water-cooled engine that prevents the engine from overheating by controlling the engine speed to a set rotation speed.

[Technical Background of the Invention] In an internal combustion engine, it is not possible to extract all of the heat energy generated by combustion as power, and most of the heat is transferred to various parts of the engine. If this heat is not released to the outside, the engine will overheat and continue operating, so the engine is cooled using air cooling, water cooling, or other methods.

[Problems with Background Art] Among internal combustion engines that perform such cooling, in water-cooled engines, such as water-cooled outboard engines, a water pump sucks up cooling water to cool the engine. However, if the cooling water cannot be supplied due to clogging of the cooling water suction port or feeding passage due to corrosion, or a malfunction of the water pump, the engine will overheat.

Therefore, in the past, a temperature detector was attached to the engine's cylinder head, etc., and when the engine overheated and the temperature exceeded a set temperature, an alarm was activated or the engine speed was controlled. However, the temperature detection method detects when the cooling water runs out and the engine reaches an overheating state, so it is very difficult to set the temperature of the temperature sensor. Therefore, depending on the temperature setting, the sensor may be detected in a normal state or may be detected after overheating. Additionally, since the temperature of the detection section changes depending on factors on the engine side, it is necessary to adjust and check the set temperature when the engine specifications are changed. Furthermore, in order to ensure sufficient heat transfer to the temperature detection part, care must be taken in the mounting position and mounting method, and since the presence or absence of cooling water cannot be detected when the machine is cold immediately after startup, inspection must be performed through the water inspection hole, making maintenance difficult. Inspection was a pain.

As described above, since overheating prevention measures using only a temperature sensor have the above-mentioned disadvantages, a method in which a temperature sensor is combined with a water pressure sensor has been proposed. However, depending on the water pressure setting, the water pressure sensor may operate during low load operation, or
If the water pressure is set to low and the water pressure sensor is activated during high-load operation, overheating has progressed and there is no room to take countermeasures, which is inconvenient.Additionally, the structure becomes more complicated due to an increase in the number of parts. I'm inviting you.

[Object of the Invention] Therefore, the object of the present invention is to detect the presence or absence of cooling water, and if there is no cooling water, immediately detect it and issue an alarm, and when the engine speed is above a predetermined rotation speed, the engine speed is further increased to a predetermined rotation speed. An object of the present invention is to realize a cooling water detection device for a water-cooled engine that can prevent overheating of the engine by controlling the temperature to a level lower than that of the engine and avoid damage caused by overheating.

[Structure of the Invention] In order to achieve this object, the present invention includes a detection means for detecting the presence or absence of cooling water in a water-cooled engine, an alarm means activated by a signal indicating that there is no cooling water from the detection means, and a predetermined engine rotation speed. In the above, the present invention is characterized in that a control means is provided for controlling the internal combustion engine to less than the predetermined engine speed based on a signal from the detection means indicating that there is no cooling water.

[Embodiments of the invention] Next, embodiments of the present invention will be described in detail based on the drawings.

The drawings show an embodiment of the invention, in which FIG. 1 is a side view of an outboard engine, FIG. 2 is a front view of a cylinder head, and FIG. 3 is an enlarged sectional view taken along the line mm in FIG. 2. In the figure, 2 is an outboard engine, and a water-cooled internal combustion engine 4 is installed inside. internal combustion engine 4
are arranged horizontally in two vertical rows, with a flywheel magnetro placed above. Flywheel magnetro has spark plugs 1O and 10 attached to cylinder head 8.
distribute high voltage to The spark plugs 10 and 1O ignite and burn the air-fuel mixture generated in the carburetor 12 to drive the internal combustion engine 4. Driven by the internal combustion engine 4, the propeller 14 is rotated and the water pump 16 is driven, and the cooling water sucked up from the suction port 18 is fed to the internal combustion engine 4 via the feed pipe 20. The internal combustion engine 4 is cooled by this cooling water.

A cooling water sensor 22 is located above the internal combustion engine 4 of the outboard engine 2 configured as described above, and detects the presence or absence of cooling water.
will be established. The cooling water sensor 22 is provided above the cylinder head 8, preferably facing the uppermost cooling water passage 24, as shown in FIG. 2.3. The cooling water sensor 22 uses the cylinder head 8 facing the cooling water passage 24 as one electrode,
An electrode rod 28 facing the cooling water passage 24 held in a main body 26 made of a non-conductor such as resin is configured as the other electrode. This electrode rod 28 is held within the main body 26 by a sealing member 30 made of a material such as heat-resistant glass that prevents water droplets and other substances from adhering to its surface. The tip side of the electrode rod 28 facing the cooling water passage 24 is formed into a hemispherical shape together with the sealing member 30, and together with the surface properties of the sealing member 30, a structure is created in which water is difficult to stay at the tip when the cooling water runs out. to form.

Further, a lead wire 32 is connected to the base end side of the electrode rod 28, and the connecting portion is molded with a mold member 34. Note that 36 is a gasket which prevents water leakage when the main body 26 is attached to the cylinder head 8 by screwing or the like with the tip of the electrode rod 28 facing the cooling water passage 24.

The cooling water sensor 22 has a cooling water flowing through the cooling water passage 24 and in contact with both electrodes as a conduction path, and detects the presence or absence of the cooling water based on a change in resistance value. In this embodiment, the cylinder head 8 side facing the cooling water passage 24 is used as one electrode, and the electrode rod 28 side is used as the other electrode, and the presence or absence of cooling water is detected by a change in resistance value. That is, when cooling water is flowing, the cylinder head 8 and the electrode rod 28 are electrically connected with each other using the cooling water as a conduction path, and the resistance value is small.

When the cooling water runs out, the cylinder head 8 and the electrode rod 28 are not electrically connected because there is no cooling water to serve as a conduction path, and the resistance value becomes infinite. Therefore, when the resistance value is small, it is detected that there is cooling water, and when the resistance value is infinite, it is detected that there is no cooling water. It is also possible to provide two electrode rods spaced apart and detect the presence or absence of cooling water from the change in resistance between the two electrode rods.

This cooling water sensor 22 has a circuit configuration as shown in FIG.

In the figure, 38 is an ignition circuit of a capacitor discharge type ignition device. This ignition device includes a capacitor charging coil 40
The output of the diode 42 is rectified, and the capacitor 44 is charged. When the gate voltage generated by the pulser coil 46 is applied to the gate of the thyristor 48, the capacitor 44
The electric charge is discharged, a current flows through the ignition coil 5O, and a spark is generated in each spark plug 10.

52 is a rotation speed control circuit. The rotation speed control circuit 52 includes a thyristor 54 and a rotation speed detection circuit 56 that turns the thyristor 54 on and off. Thyristor 54
The anode of the diode 4 provided in the ignition circuit 38
Connected to the cathode of 2, while the power sword is grounded.

A rotation speed detection circuit 56 is connected to the gate of this thyristor 54.
Connect the output end of the The rotation speed detection circuit 56 inputs the output from the pulser coil 46, and energizes the gate of the thyristor 54 when the engine rotation speed is equal to or higher than a predetermined rotation speed.

With this energization, the thyristor 54 short-circuits the capacitor 44 of the ignition circuit 48 and discharges the spark plugs 10 and 10.
does not generate sparks, and the internal combustion engine 4 is controlled to below a predetermined rotation speed. This rotation speed control circuit 52 is configured to operate only when the cooling water sensor 22 detects that there is no cooling water, as will be described later.

The signal from the cooling water sensor 2-2 is input to a drive circuit 58. Cooling water sensor 22 is connected to the base of transistor Tri. The collector of the transistor Tri is connected to the base of the transistor Tr2, and the collector of the transistor Tri is connected to the base of the transistor Tr2.
The collector of r2 is connected to the base of transistor Tr3. These transistors Tr2 and Tr3 are connected in parallel to a power source 60 supplied via a switch Sv. The emitter of the transistor Tr3 is connected to the base of the transistor Tr4, and the collector of the transistor Tr4 is connected to the buzzer 62 and the rotational speed detection circuit 56 so that the power supply 60 is supplied/disconnected by the transistor Tr4. Therefore, when the resistance value of the cooling water sensor 22 is infinite to detect that there is no cooling water, the transistor T
r4 is turned on to energize the buzzer 62 and the rotation speed detection circuit 56. When cooling water is flowing and the resistance value is small,
The transistor Tr4 is turned off, cutting off power to the buzzer 62 and the rotation speed detection circuit 56. Therefore, the rotational speed control circuit 52 controls the internal combustion engine 4 to operate at a predetermined rotational speed or higher and below the predetermined engine rotational speed when the cooling water sensor 22 detects the absence of cooling water.

Next, this invention will be explained in detail.

When the internal combustion engine 4 is started, the water pump 16 is driven and starts supplying cooling water. This cooling water is supplied to the feed pipe 2
It takes a certain amount of time from the start until the engine passes through 0 and reaches the cooling water sensor 22 located at the top of the cooling water passage 24.

Therefore, until the cooling water reaches the cooling water sensor 22, the resistance between the cylinder head 8 and the electrode rod 28 becomes infinite. Therefore, current flows from the power supply 60 to the base of the transistor Tri of the drive circuit 58, and the transistor Tri is turned on. When the transistor Tri is turned on, the transistor Tr2 is turned off and the transistor Tr3 is turned on, and a current flows through the base of the transistor Tr4, turning it on. Transistor Tr
4 is turned on, current flows through the buzzer 62 to make it sound and issue an alarm. Current also flows through the rotational speed detection circuit 56, but since the engine rotational speed is low immediately after starting, the rotational speed control circuit 52 does not operate and does not affect the engine. At this time, even if the engine rotation speed is increased, the rotation speed control circuit 52 operates and does not generate sparks in the spark plugs 10, so the internal combustion engine 4 is controlled to be less than the predetermined rotation speed.

The buzzer 62 stops sounding when the supplied cooling water reaches the cooling water sensor 22. Cooling water is detected by cooling water sensor 2
2, the cylinder head 8 and the electrode rod 28 are electrically connected using the cooling water as a conduction path, and the resistance value becomes small. Therefore, the current flowing to the base of the transistor Trl decreases, and the transistor Trl is turned off. When the transistor 'l'rl is turned off, the transistor Tr2 is turned on, the transistor Tr3 is turned off, and the transistor Tr4 is turned off. When the transistor Tr4 is turned off, the power supply to the circuit of the buzzer 62 is cut off and the sounding is stopped. By stopping the buzzer 62, it is possible to confirm that the cooling water has started to be normally fed when the engine is started.

In other words, it can be confirmed that the normal operating state has been reached. if,
If the buzzer 62 does not stop sounding, it means that the cooling water is not being supplied normally, and an abnormality in the engine can be detected.

When the engine is operating at high speed, if cooling water no longer comes into contact with the cooling water sensor 22 due to, for example, a blockage in the suction port 18 or the feed pipe 20 or a malfunction in the water pump 16, there will be no conduction between the cylinder head 8 and the electrode rod 28. Since there are no passages, the resistance value becomes infinite.

Therefore, as described above, the transistor Tr4 is turned on, and the buzzer 62 and the rotation speed detection circuit 56 are energized. When the rotational speed detection circuit 56 detects that the engine is rotating at a predetermined rotational speed or higher through this energization, it discharges the capacitor 44 of the ignition circuit 38 to prevent the spark plugs 10 from generating sparks. Therefore, when the cooling water sensor 22 detects that there is no water, the buzzer 62 sounds and the internal combustion engine 4 is controlled to below a predetermined rotation speed, so that a failure in the supply of cooling water is immediately detected and a warning is issued, and the engine Overheating can be prevented by lowering the rotation speed. Therefore, the cause of overheating can be quickly investigated and countermeasures can be taken, and damage to the engine due to overheating can be avoided.

If the cause of the activation of the buzzer 62 and rotational speed control circuit 52 is eliminated, the cooling water will be supplied normally, the buzzer 62 will stop, and the engine can rotate normally.

In this embodiment, a buzzer 62 is used as an alarm means.
Although exemplified above, other light-emitting bodies such as lamps, sounds, or a combination of these may also be used.

Further, the present invention is of course applicable not only to outboard engines but also to vehicle engines.

[Effects of the Invention] As described above, according to the present invention, it is possible to immediately detect the absence of cooling water and issue an alarm, and if there is no cooling water at a predetermined engine speed or higher, the engine speed is further reduced to below a predetermined engine speed. By controlling the engine, overheating of the engine can be prevented. Therefore, the cause of overheating can be investigated and countermeasures can be taken with sufficient time, and damage to the engine due to overheating can be avoided.

[Brief explanation of the drawing]

The figures show an embodiment of the present invention, in which Fig. 1 is a side view of the outboard engine, Fig. 2 is a front view of the cylinder head, Fig. 3 is an enlarged sectional view taken along the line mm in Fig. 2, and Fig. 4. is a circuit diagram. In the figure, 4 is a water-cooled internal combustion engine, 8 is a cylinder head, 22 is a cooling water sensor, 24 is a cooling water passage, 28 is an electrode rod, 38 is an ignition circuit, 52 is a rotation speed control circuit, and 58 is a drive circuit 1 .62 is a buzzer. Proceedings (spontaneous) January 30, 1980 Director-General of the Patent Office Kazuo Wakasugi 1, Indication of the case Patent Application No. 241014 of 1988 2, Title of the invention Cooling water detection device for water-cooled engines 3, Relationship with the person making the amendment Patent applicant address 300 Takatsuka, Kami Village, Hamana District, Shizuoka Prefecture Name (20
8) Suzuki Motor Co., Ltd. Representative Osamu Suzuki 4, Agent 105 K 03-438-224
1 (Representative) Address: 3-4-17 Toranomon, Minato-ku, Tokyo
No. Rokuto Building 3, 4th Floor Name (8005) Patent Attorney Nishigin Do Yoshimi (1 idiot) 5. Date of amendment order Voluntary 6.? ! Positive object Detailed explanation of the invention in the specification column 7,
Contents of correction (1), page 8, line 12 of the specification, "When applied, the capacitor 44" is corrected to "When applied, the thyrisk 48 is turned on and the capacitor 44 is turned on." (2), page 9 of the specification, lines 5 to 7, “Thyristor 54
is discharged, so "thyristor 54 is turned on and capacitor charging coil 4O is short-circuited, so capacitor 4
4 is not charged, therefore, the correction is made as follows. (3), page 13, line 1 of the specification: “Ignition circuit 38...
``The capacitor 44 is not charged because the thyristor 54 is turned on and the capacitor charging coil 4O is short-circuited.'' Proceeding (authorized by Ichimasa) June 15, 1980 Kazuo Wakasugi, Commissioner of the Japan Patent Office1, Indication of the case, Patent Application No. 241014 of 19882, Name of the invention, Cooling water detection device for water-cooled engine 3, Amendment Relationship with the case of a person who does
B) Suzuki Motor Co., Ltd. Representative Osamu Suzuki 4, Agent Address: 105 03-438-224
1 (Representative) Address: 3-4-17 Toranomon, Minato-ku, Tokyo
No. 5, Date of amendment order Voluntary action 6, Subject of amendment Detailed explanation of the invention in the specification Column 7, Contents of amendment

Claims (1)

[Scope of Claims] 1. A detection means for detecting the presence or absence of cooling water in a water-cooled engine; an alarm means activated by a signal from the detection means indicating that there is no cooling water; A cooling water detection device for a water-cooled engine, comprising: a control means for controlling the internal combustion engine to below the predetermined engine rotation speed by a signal indicating that the internal combustion engine is running at a speed of less than the predetermined engine speed. 2. The cooling water detection device for a water-cooled engine according to claim 1, wherein the cooling water detection means i is provided at or near the top of the cooling water passage of the front-loaded water-cooled engine. . 3. The cooling water detection means has one electrode on the cylinder head facing the cooling water passage of the water-cooled engine, and has the other electrode facing the cooling water passage, and has a cooling shoe traction between the two electrodes. The cooling water detection device for a water-cooled engine according to claim 2, wherein the cooling water detection device for a water-cooled engine is configured as a passage and is characterized by the presence or absence of the cooling water. 4. The cooling water detection means is provided with two electrodes facing and separated from the cooling water passage of the water-cooled engine, and the cooling water between the two electrodes is configured as a conduction path to detect the presence or absence of the cooling water. A cooling water detection device for a water cooling system according to claim 2.