JPH02271075A - Heating device of internal combustion engine - Google Patents

Abstract

PURPOSE:To shorten the preparation time for start at very low temperature by arranging a heating means for heating cooling water in the middle of bypass pipelines which communicates to a cylinder head and water jackets of a cylinder block. CONSTITUTION:Cooling water of a cylinder head 3 and water jackets 4 and 5 of a cylinder block 2 is circulated in a radiator through a pump, and bypass pipelines 6 and 7 which communicates to both the water jackets 4 and 5 are provided. In the middle of the bypass pipelines, a heating device 10 for cooling water having a switch valve 22, a heat exchange pipe 13, a fuel injector 14, an ignition plug 18 and so on is arranged. An ECU 50 opens the switch valve 21 at cold start, operates a pump 18 and the fuel injector 14 so as to ignite and burn fuel by the ignition plug 18, heats cooling water in the heat exchange pipe 13 to be convectively circulated in the water jackets 4 and 5. In this way, heating time necessary for start is reduced and stable start is enabled even at very low temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a heating device for improving cold startability of an internal combustion engine.

(Prior art) In order to ensure the startability of an internal combustion engine when it is cold,
As stated in Publication No. 1-44739, there is a device that heats the cooling water by installing a heater in the middle of the engine cooling water circulation passage and energizing the heater prior to cranking during a cold start. be.

This is done by installing a heater in the middle of the path where the cooling water from the rotor knob is led to the radiator, heating the cooling water by energizing the heater, and directing the heated cooling water to the water jacket of the engine body. It circulates and warms the engine body, improving the startability of a cold engine, such as in extremely cold weather.

(Problem to be Solved by the Invention) However, in this heating device, the heater is directly installed in the cooling water circulation passage of the engine, so the heated cooling water is distributed from the radiator to the cylinder block, cylinder head, and
The problem is that the amount of water that is convectively circulated to the radiator and heated becomes the entire amount of cooling water, so it takes time to warm up the engine and the power consumption required for heating is large.

In addition, because the heater is installed in the cooling water circulation passage, the thermostat cannot be used due to the operating characteristics of the thermostat that controls the temperature of the cooling water during normal operation (the thermostat does not close the circulation passage at low temperatures). (If this happens, the coolant heated by the heater cannot be circulated to the cylinder head and cylinder block side.) In this case, when the temperature is too cold to operate the heater, the entire amount of coolant is circulated to the radiator by the water pump. As a result, warming up after starting is extremely slow.

Additionally, there is also a warm-up device that warms up the engine before starting by installing a cooling water heating source outside the vehicle and connecting it with piping so that hot water from the heating device is introduced into the engine cooling water circulation passage. However, in this case, it is necessary to move the car to a place where the heating device is located, and it is necessary to connect the piping each time, and the operation after starting the engine is necessary. There are significant restrictions on operability and usage conditions, such as not being able to use anything inside.

The present invention aims to solve such problems.

<Means for Solving the Problems> Therefore, the present invention constitutes a circulation passage that circulates the cooling water of the water jacket of the cylinder head and the cylinder block to the radiator via the water pump, and the water jacket of the cylinder head and the cylinder block. A bypass line communicating with the jacket was provided, and cooling water heating means was interposed in the middle of this bypass line.

(Function) Therefore, by activating the heating means such as during a cold start of the engine, the heated cooling water flows from the bypass pipe to the water jacket of the cylinder head by natural convection, causing the water jacket of the cylinder block to flow into the water jacket of the cylinder block. Low-temperature cooling water flows into the heating means through the bypass pipe, and the heated cooling water circulates convectionally between the cylinder head and the cylinder block, thereby warming the engine body.

Cooling water for warming up does not pass through the radiator, but flows between the cylinder head and cylinder block in a short circuit, so the amount of water that circulates by convection is small, and the heating time required for startup is shortened.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

Ru.

As shown in FIGS. 1 and 2, outer jackets 4 and 5 are formed inside the cylinder block 2 and cylinder head 3 of the engine body 1, respectively, and are connected to a water pump and a radiator (not shown) through circulation passages. The engine body 1 is cooled by forcibly circulating cooling water.

A water heater 10 (cooling water heating means) is provided in order to heat the engine body 1 by adding cooling water to the engine body 1 before starting the engine when the engine is cold. This water heater 10 is interposed between the bypass pipes 6 and 7 that short-circuit the water jackets 4 and 5, and heats the cooling water by natural convection.

As shown in FIGS. 3 and 4, the water heater 10 includes a heat exchange pipe 13 wound spirally in a combustion chamber 15 inside a vertically long housing 12 surrounded by a heat insulating material 11.
is provided, and this heat exchange vibe 13 is connected to the bypass pipes 6 and 7.

A fuel injector 14 is attached to the end of the housing 1'2, and when ignited by a spark plug 18, combustion occurs in a combustion chamber 15 while taking in air from an air port 16 formed in a conical partition wall 17.

Fuel from a fuel tank 20 is pumped to the fuel injector 14 via a pump 19.

These, fuel injector 14, spark plug 18, pump 1
Reference numeral 9 indicates that when a key switch (not shown) is turned on when starting the engine, the water temperature reaches a heating set value (for example, -15 It is activated when the temperature is below the set value (e.g. 0'''C) and the temperature is released by heating.
), the operation can be stopped.

As shown in FIG. 3, the water heater 10 is mounted perpendicularly to the side surface of the cylinder block 2 to facilitate circulation of cooling water in the water jackets 11 and 5 by natural convection.

A valve machine t1121 is provided to control the working fluid of the water heater 10.

The valve mechanism 21 includes an on-off valve 22 for circulating cooling water to the overheater 10, an on-off valve 23 for fuel to the fuel injector 14, an on-off valve 24 for combustion air, and an on-off valve 25 for combustion exhaust.

The cooling water valve 22 is interposed in the bypass pipe 6.7 and opens only when the cooling water temperature is in an extremely low temperature range of, for example, 0°C or lower. Similarly, the fuel valve 23 connects the fuel pipe 27 from the fuel pump 19 to the The air valve 24 opens the air introduction pipe 28, and the exhaust valve 25 opens the two exhaust pipes.

For this reason, in this embodiment, the valve mechanism 21 is configured to sense the cooling water temperature and automatically open and close, as shown in FIG.

A valve spool 31 is slidably inserted into the valve body 30, and a thermostat 33 is connected to the end of the valve spool 31, which opens and closes by thermal expansion and contraction of the wax 32. The valve spool 31 has a valve body 24 that opens and closes the air introduction pipe 28. a, and the valve body 2 that opens and closes the fuel pipe 27
3a and a valve body 25a that opens and closes the exhaust pipe 29. When the wax 32 contracts at extremely low temperatures and the thermostat valve 22a is opened by the spring 34, the valve spool 31 moves integrally with this and the valve body 25a opens and closes the exhaust pipe 29. They are designed to open at the same time.

The thermostat 33 connects the water jacket 4 to the water heater 1o by opening the cooling water bypass line 6.
and 5. circulate the cooling water.

Note that the operating (temperature) characteristics of the thermostat 1-33 can be controlled by moving the bushing rod 36 forward or backward in the threaded engagement position with respect to the stay 37.

When the temperature of the cooling water rises above the set value (0°C) due to the heating operation of the water heater 10, the expansion of the wax 32 causes the thermostatic valve 22 to move against the bushing rod 36.
a moves and comes into close contact with the three seat parts, but as a result, the circulation of cooling water is stopped, and the thermostat 33 is cooled by external cold air, such as at extremely low temperatures, and the thermostat valve 22a opens again. In order to prevent such a hunting phenomenon, the operation of the thermostat 33 is stabilized by forming a minute hole 40 in the thermostat valve 22a and circulating the cooling water little by little.

This valve mechanism 21 is located below the water heater 10 and attached to the side surface of the cylinder block 2, as shown in FIG.

As shown in FIG. 2, the combustion exhaust discharged from the combustion chamber 15 of the water heater 10 is guided to the intake heater 45 interposed in the intake passage 44 of the engine body 1 via the exhaust pipe 29a. After exchanging heat with the engine intake air, it passes through the exhaust pipe 29 and the exhaust valve 25 to the exhaust passage 43 of the engine body 1.
It flows on its own in the middle of the day. By introducing the exhaust gas discharged from the water heater 10 into the intake heater 45, the heat of the combustion gas warms the intake air to improve startability and warm up. The oil may be heated entirely or guided around the oil pan.

In addition, in the case of a turbocharged engine, the confluence point of the exhaust pipe 29 to the JU air passage 43 is on the downstream side of the exhaust turbine where exhaust pressure is low, but when the confluence point is upstream of the exhaust turbine, a blower is connected to the air introduction pipe 28. installed to increase the supply pressure of combustion air.

In the figure, 46 indicates an air cleaner, and 47 indicates a high voltage circuit.

The system is configured as described above, and the overall operation will be explained next.

When starting the engine in extremely cold weather, first turn on the ignition key, and if the temperature detected by the water temperature sensor 51 is below the set value of -15°C, the controller 50 operates the fuel pump 19 and the fuel injector 14 is activated.
At the same time, fuel is injected from the ignition plug 18 and ignited by the ignition plug 18, thereby starting the heating operation of the water heater 10. Note that the ignition operation by the spark plug 18 is performed only at the start of combustion by the output of the high voltage circuit 47.

Since the temperature of the cooling water in the valve mechanism 21 is lower than the set value, the thermostat 33 works and the valve spool 31 moves together with the thermostatic valve 22a.

Each of the valve bodies 23a to 25a is open.

Due to the heating operation of the water heater 10, the heat exchange pipe 1
When the cooling water of cylinder block 2 is heated, the cooling water flows from the bypass pipe 6 to 7 by natural convection using the pressure head difference between the cylinder block 2 and the cylinder head 3, and the cooling water flows into the oak jacket 5 of the cylinder block 2. Cooling water from the cylinder head 3 circulates by convection through the water heater 10 to the water jacket 4 of the cylinder head 3.

Since the cooling water from the water heater 10 only circulates between the cylinder head 3 and the cylinder block 2, unlike heating the entire engine cooling system, it is efficiently heated, and the engine body 1 is quickly warmed up. It is done.

At the same time, the combustion exhaust from the water heater 10 is also guided to the intake heater 45, thereby warming the intake air in the intake passage 44 and improving the startability of the engine.

In this way, the temperature of the cooling water is set to the set value (for example, 0°C).
When the water heater 10 rises to this level, the thermostat 33 of the valve mechanism 21 closes the valves 22 to 25, cutting off the supply of fuel and air, and automatically stops combustion in the water heater 10. At the same time, the bypass pipe 6 and The two exhaust pipes are closed, stopping the circulation of cooling water and preventing backflow of exhaust gas from the exhaust passage 43 after the engine is started.

Note that when the coolant temperature rises above a set value, the controller 50 stops the operation of the fuel pump 19 and the spark plug 18.

The cooling water is heated by the water heater 10 through natural convection circulation that utilizes the height difference between the cylinder head 3 and the cylinder block 2, and does not require a pump or the like for circulation.
In addition, the only load on the battery is the operation of the fuel pump 19 and the spark plug 18 when igniting, and power consumption is extremely small.

Furthermore, after the water heater 10 stops operating, the valve mechanism 21 shuts off the bypass pipes 6 and 7, so there is no effect on the flow of cooling water after the engine is started, and the radiator The temperature of the cooling water can be controlled as usual by circulating it.

Incidentally, this water heater 10 is not only used to assist in starting, but also to promote warm-up after starting, so that it can be operated at the same time even after engine operation has started as long as the temperature of the cooling water is below a set value (0°C). .

If the engine is started before the heating by the water heater 10 is finished, by using the heating by the water heater 10 in combination, the cooling water can be warmed and the warm-up of the engine can be promoted.

Note that while the water heater 10 is operating, the fuel injector 1
4 increases the pressure of the combustion gas, so the exhaust passage 43
Exhaust air will not flow backwards.

Figure 6 is a flowchart schematically showing the flow of cooling water in the warm-up side and warm-up head before starting the engine. Before starting, the cooling water in the cylinder block and cylinder head only circulates through the water heater. , On the other hand, from the start until the end of warm-up, the water inlet, water pump,
Coolant circulates through the cylinder block, cylinder head, thermostat housing, thermostat (which controls the temperature of the entire coolant circulation system), water pump, and some of it also flows to the heater for heating the cabin.

After warming up, the thermostat operates and the cooling water flows from the water outlet to the radiator.
Cool the engine to an appropriate temperature.

(Effects of the Invention) As described above, according to the present invention, a water heater is provided in the bypass pipe that short-circuits between the cylinder head and the cylinder block, and the cooling water is heated by the water heater when starting the engine, etc. As a result, by circulating natural convection, it is possible to efficiently heat the cooling water for only the cylinder head and cylinder block necessary for warming up in a short time, rather than the entire amount of cooling water. A significant reduction in preparation time and stable startability can be achieved.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of the present invention, FIG. 2 is a plan view, and FIG. 3 is a sectional view showing a specific configuration.
FIG. 4 is a sectional view of the water heater. FIG. 5 is a sectional view of the valve mechanism, and FIG. 6 is a flowchart schematically showing the circulation of cooling water depending on the operating state. 1... Engine body, 2... Cylinder block, 3...
・Cylinder head, 4.5... water jacket,
6゜7...Bypass pipe line, 10...Water heater, 21...Valve mechanism. L/"?', IF! Figure 1

Claims (1)

[Claims] A circulation passage is configured to circulate the cooling water in the water jacket of the cylinder head and cylinder block to the radiator via the water pump, while a bypass pipe is provided that communicates with the water jacket of the cylinder head and cylinder block. A heating device for an internal combustion engine, characterized in that a cooling water heating means is interposed in the middle.