JPH0326253Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Field of Application> The present invention relates to a warm-up promotion device for a water cooling system of an engine, and provides one that can perform quick warm-up operation while preventing piston seizure.

Further details of the field of application of the technology on which the present invention is based include, for example, Figures 1 and 4.
As shown in the figure, when the thermostat valve 2 is opened, the cooling water for the engine E is pumped through the water pump 1 from the cylinder jacket 3 to the head jacket 4, the thermostat valve chamber 5, the radiator 6, and the water pump 1.
water is circulated through the cylinder jacket 3 in order, and when the thermostat valve 2 is closed, it is short-circuited from the thermostat valve chamber 5 to the water pump 1 via the bypass 7, so that the water does not circulate to the radiator 6.

<Prior art> In the conventional warm-up acceleration device, for example, the fourth
As shown in the figure, when the engine is warmed up after a cold start, the thermostat valve 2 closes.
The cooling water is not passed through the radiator 6 to promote warm-up, and at the same time, the cooling water is slightly circulated through the bypass 7 to uniformly heat the entire cylinder block 14 and cylinder head 15.

<Problems that the invention attempts to solve> However, the amount of water flowing through bypass 7 is small;
Among the cylinder jackets 3 and the cylinder jackets 4, the parts of the jackets 3 and 4 that are further away from the thermostat valve chamber 5 have poor flow of cooling water and are difficult to cool, so they reach high temperatures. Become. If a load is applied during warm-up,
becomes extremely hot. Furthermore, for operation in extremely cold weather, the higher the mixing ratio of antifreeze in the cooling water, the higher the boiling point of the cooling water, which further promotes the high temperature of the distant jacket portions 3 and 4.

For this reason, the distant jacket parts 3, 4 are
It is heated to a much higher temperature than the thermostat valve chamber 5, and the thermostat valve 2 opens, causing the radiator 6 to open.
There is a problem in that when the cold cooling water inside flows in, it cools down rapidly and the cylinder 18 rapidly contracts or becomes distorted, causing the piston to seize.

<Means for solving the problem> The present invention is intended to solve the above problem, and was proposed for the purpose of preventing seizure of the piston during warm-up operation. Means for achieving this will be explained using FIG. 1 which corresponds to an embodiment.

That is, an overheat prevention valve 8 is provided in the thermostat valve chamber 5 in parallel connection with the thermostat valve 2, and a water temperature sensor 10 that commands the opening of the overheat prevention valve 8 is connected to at least one of the cylinder jacket 3 and the head jacket 4. The valve opening command temperature To of the water temperature sensor 10 is set higher than the valve opening temperature T of the thermostat valve 2 to the boiling point of the cooling water. It is set at a lower temperature.

<Function> Therefore, to describe the function of the present invention brought about by the above configuration, when the engine is warmed up,
The thermostat valve 2 and the overheat prevention valve 8 are closed, and the cooling water that has flowed into the thermostat valve chamber 5 from the head jacket 4 is circulated to the cylinder jacket 3 through the bypass 7, so it is quickly circulated without passing through the radiator. It can warm up the inside of the engine.

However, if the water temperature at the end 12 of the head jacket 4 opposite to the end 11 that communicates with the thermostat valve chamber 5 locally rises above a predetermined temperature, the water temperature sensor 10 provided at that location will detect the water temperature. When an abnormal rise is detected, the overheating prevention valve 8 is opened and a part of the cooling water that is about to be circulated from the thermostat valve chamber 5 to the cylinder jacket 3 is diverted to the radiator 6, and the cooling water that passes through the bypass 7 is diverted. A more abundant amount of water is circulated through the jackets 3 and 4.

When the temperature inside the jacket becomes homogenized through circulation to the radiator 6 and the water temperature near the water temperature sensor 10 decreases, the overheat prevention valve 8 closes and the temperature of the entire water cooling system rises to a predetermined temperature. The tat valve 2 is opened, the radiator starts its original cooling function, and the engine continues to operate normally.

<Effect of the invention> Therefore, according to the invention, when the head jacket locally rises to a predetermined temperature during warm-up operation, a relatively abundant amount of cooling water is immediately circulated within the jacket to cool the head jacket. It can homogenize the temperature inside the jacket and prevent localized overheating.

Therefore, even if the load increases during warm-up operation, the above-mentioned overheating state can be smoothly avoided. Therefore, even when switching to normal operation and cold cooling water flows into the jacket, there is no significant temperature difference. This prevents the cylinder from contracting and causing the piston to seize.

In addition, during normal engine operation, even if local overheating is resolved and the overheat prevention valve is closed, the thermostat valve remains open, so the water heated inside the engine is cooled by the radiator and then circulated. , abnormal temperature rise during normal operation can be smoothly resolved.

<Example> Hereinafter, an example of the present invention will be described based on the drawings.

FIG. 1 is a schematic longitudinal sectional side view of a vertical water-cooled engine. In the vertical water-cooled engine E, a cylinder head 15 and a head cover 16 are fixed above a cylinder block 14, and a cooling fan 17 and a radiator 6 are arranged in front of the cylinder head 15 and head cover 16. do.

The cylinder block 14 has a cylinder jacket 3 formed in the gap between four cylinders 18 arranged in parallel in the front and rear, and connects the outlet 20 of the cylinder jacket 3 to the head jacket 4 formed in the cylinder head 15. It communicates on the rear side.

Further, a water pump chamber 21 is provided behind the cooling fan 17, and a rotor 23 is mounted on the fan shaft 22.
is accommodated in the water pump chamber 21 to form the water pump 1, and the crankshaft 24 is connected to the fan shaft 22 with the belt 2.
5.

A thermostat valve chamber 5 is formed above the water pump chamber 21, and an overheat prevention valve 8 linked to the thermostat valve 2 and the solenoid 27 is connected in parallel with the partition plate 26 as a boundary. side, i.e., the end 1 of the head jacket 4 on the side communicating with the thermostat valve chamber 5
The water temperature sensor 10 attached to the end 12 on the opposite side from 1 is connected to the solenoid 27, the valve temperature T of the thermostat valve 2 is set to approximately 82°C, and the valve opening command temperature To of the water temperature sensor 10 is set. Approximately 100℃ (i.e.
Set the temperature at a temperature higher than T°C and lower than the boiling point of the coolant).

On the other hand, the radiator 6 has its inlet 30 connected to the outlet 31 of the thermostatic valve chamber 5, and its outlet 32
is connected to the inlet 33 of the water pump chamber 21.

The water pump chamber 21 also has an inlet 33 communicating with the thermostat valve chamber 5 via the bypass 7, and an outlet 34 with the inlet 35 of the cylinder jacket 3.

The functions of the warm-up accelerating device thus constructed are as follows: (1) During warm-up operation, the temperature of the cooling water is not high, so the thermostat valve 2 and the overheat prevention valve 8 are closed (see Figure 2); The cooling water is routed in the order of water pump chamber 21 → cylinder jacket 3 → head jacket 4 → thermostat chamber 5 → bypass 7 → water pump chamber 21.
It circulates in a short circuit without passing through the radiator 6,
This quickly warms up the inside of engine E.

(2) However, if the vicinity of the inlet 12 of the cooling water from the cylinder jacket 3 to the head jacket 4 is locally overheated during the warm-up operation (i.e., reaches the valve opening command temperature To°C), the water temperature sensor 10 detects this abnormal temperature rise and opens the overheating prevention valve 8 (see Figure 1), so the cooling water circulates through the short-circuit cycle described in (1) above, and part of it flows through the water pump. The water circulates in the order of chamber 21 → cylinder jacket 3 → head jacket 4 → thermostat chamber 5 → radiator 6 → water pump chamber 21, and the cooling water cooled by radiator 6 is supplied to the engine to make the water temperature inside the jacket uniform. This reduces the amount of heat generated in the engine, eliminates local heating of the engine, and smoothly prevents piston seizure.

(3) When the entire cooling water temperature rises uniformly and reaches a predetermined temperature T℃ or higher, the thermostat valve 2
opens the valve (at this time, the head jacket 4
Since the local heating near the inlet 12 of the cooling water inside the tank has been eliminated, the overheating prevention valve 8 remains closed (see Figure 3), and all the cooling water is flowing into the water pump chamber 21. → Cylinder jacket 3 → Head jacket 4 → Thermostat chamber 5 → Radiator 6 → Water pump chamber 21 The cooling water is circulated in this order, and the cooling water heated in the engine E is cooled by the radiator 6 and flows into the engine again. .

Therefore, the cooling water circulating within the engine is homogenized along its flow, and a rise in temperature during engine operation is automatically prevented.

[Brief explanation of the drawing]

Figures 1 to 3 show an embodiment of the present invention, with Figure 1 being a schematic vertical side view of a vertical water-cooled engine showing the operating state of the overheating prevention valve, and Figure 2 showing the warm-up operation state. 3 is a view corresponding to FIG. 2 showing a normal operating state, and FIG. 4 is a view corresponding to FIG. 1 showing a conventional example. 1...Water pump, 2...Thermostat valve, 3...Cylinder jacket, 4...Head jacket, 5...
Thermostat valve chamber, 6...Radiator, 7...Bypass, 8...Overheat prevention valve, 10...Water temperature sensor, 1
2...4 end.

Claims (1)

[Scope of Claim for Utility Model Registration] Cooling water for the engine E is passed through the cylinder jacket 3, the head jacket 4, the thermostat valve chamber 5, the radiator 6, and the water pump 1 in order by the water pump 1 when the thermostat valve 2 is opened. At the same time, when the thermostat valve 2 is closed, the thermostat valve chamber 5 is
In a warm-up promotion device for an engine water cooling system configured such that the water is short-circuited to the water pump 1 through a bypass 7 and not circulated to the radiator 6, a heating prevention valve 8 is connected in parallel with the thermostat valve 2 in the thermostat valve chamber 5. A water temperature sensor 10 for instructing the opening of the heating prevention valve 8 is installed in at least one of the cylinder jacket 3 and the head jacket 4 near the end 12 on the side far away from the thermostat valve chamber 5. , and the valve opening command temperature To of the water temperature sensor 10 is set to a temperature higher than the valve opening temperature T of the thermostat valve 2 and lower than the boiling point of the cooling water. Device.