JPS60128968A - Suction heating mechanism for internal-combustion engine - Google Patents

Abstract

PURPOSE:To improve fuel consumption considerably while preventing knocking, in an internal-combustion engine for heating intake air while utilizing engine cooling liquid under high temperature condition, by feeding low temperature cooling liquid in place of high temperature cooling liquid to intake air heating section under heavy load region after warming of engine. CONSTITUTION:Under low cooling water temperature, a heat-sensitive valve (not shown) is closed to function the diaphragm unit in control valve device 14 only when the suction negative pressure from negative pressure source will reach to setting level thus to communicate between the ports 16, 17 while to block the port 18. Cooling water of relatively high temperature at the inlet path 4 side of a radiator 5 is fed abundantly through cooling water path 11 for heating intake air to the suction pipe (intake heating section) 3. Upon reaching of cooling water temperature to setting level to open the heat-sensitive valve thus to enter into heavy load region, the ports 17, 18 of a controller 14 are communicated while the port 16 is blocked to feed cooling water of relatively low temperature through a radiator 13 to said section 3.

Description

[Detailed description of the invention] (Technical field) The present invention relates to an improvement in an intake air heating device for an internal combustion engine.

(Background and prior art) In modern automobile internal combustion engines, a large amount of exhaust gas recirculation,
Emission countermeasures such as retarding the ignition timing have resulted in the inconvenience of destabilizing combustion and impairing drivability and fuel efficiency, so improvements are desired.

As one means of achieving this, various devices have been proposed that heat intake air using exhaust heat or engine cooling hot water to promote the vaporization characteristics of fuel and improve combustion.

Conventionally, this intake air heating device utilizes, for example, engine cooling water (warm water), and there is a device as shown in FIG. 1 (see Japanese Utility Model Publication No. 53-9786).

This allows engine cooling water to flow from the cylinder block 1 to the cylinder head 2, and from the cylinder head 2 to the intake pipe 3 for heating intake air via water jackets formed respectively, and a radiator inlet passage 4. The cooling water cooled by the radiator 5 is passed through the radiator 5 provided at the front of the engine, and the cooling water for heating the intake air (cooled by heat exchange with the intake air) is guided through the cooling water channel 9. ) from the radiator outlet passage 6 to said passage 6
The engine is cooled by being circulated again to the cylinder block 1 by the water pump 7 installed in the middle of the engine. Heats the intake air.

A thermostat 8 is installed in the middle of the radiator inlet passage 4.
is installed to control the amount of water flowing into the radiator 5 according to the cooling water temperature. In other words, the cooling water temperature is the set temperature (
When the temperature is below 80°C to 90°C, the thermostat 8 is fully closed, and as a result, the cooling water flowing out of the cylinder head 2 is guided to the intake pipe 3 side without being cooled by the radiator 5, and is routed to the cooling water channel 9 or the bypass passage. 1°0 and all flows into the radiator outlet passage 6.

However, in such conventional intake air heating devices,
In order to improve fuel efficiency while the engine is warming up, try increasing the passage area of the water jacket (intake air heating section) in the intake pipe 3, etc., and guide a large amount of cooling water to the intake pipe 3 to heat the intake air or air-fuel mixture. If this is the case, the flow rate of cooling water for heating will be too large in the engine low-medium-speed and high-load region from near the end of engine warm-up to after engine warm-up is completed (controlling the flow rate of cooling water led to the intake pipe 3) If the engine is not heated properly, it may overheat and cause knocking.

If the ignition timing is delayed to avoid this knocking, the torque will decrease, so in reality, the intake air heating section described above must be set to a heating capacity lower than the degree of intake air heating required during warm-up. This poses a problem in that the effect of improving fuel efficiency by promoting fuel vaporization during engine warm-up becomes insufficient.

(Purpose of the Invention) The present invention has been made by focusing on such conventional problems, and it is possible to prevent knocking in the high load range from near the end of engine warm-up, and to improve intake air heating during engine warm-up. The purpose of the present invention is to provide an intake air heating device that can significantly improve fuel efficiency by further strengthening the fuel efficiency.

(Structure and operation of the invention) In order to achieve the above object, the present invention provides a liquid-cooled internal combustion engine having an intake air heating system as described above, in which a first intake air branched from upstream of a radiator and led to an intake air heating section is provided. In the middle of the heating coolant passage, a second intake air heating coolant passage, in which a coolant having a lower temperature than that of the coolant in the passage flows, joins, and at least in the high load area after the engine warms up, a second intake air heating coolant passage is added. , a control valve device is provided to switch and control the coolant passage so that the first intake air heating coolant passage is cut off from the intake air heating unit side, while the second intake air heating coolant passage is communicated with the intake air heating unit side. It is done.

According to this, in a high load range after the engine warms up, the coolant in the first intake air heating coolant passage, which has been heated by cooling the engine, is replaced by a second intake air heater at a lower temperature. The coolant in the coolant passage is sent to the intake air heating section.

For this reason, even if the capacity of the intake air heating section is set large enough to obtain a sufficient degree of intake air heating during warm-up, for example, a large amount of high-temperature coolant will remain in the high-load region of the engine after warm-up. There is no flow, and the occurrence of knocking due to overheating is avoided.

(Example) Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIGS. 2 and 3 are a schematic configuration and a detailed cross-sectional view of essential parts showing a first embodiment of the present invention.

As shown in the figure, cooling water at a lower temperature than the cooling water in the passage 11 flows in the middle of the first intake air heating cooling water passage 11 that branches from the radiator inlet passage 4 and reaches the intake air heating section of the intake pipe 3. The downstream ends of the second intake air heating cooling water passage 12 installed outside the engine are connected together.

That is, the second intake air heating cooling water passage 12 has its upstream end branched from the radiator outlet passage 6 downstream of the water pump 7, and the sub-radiator 13 is interposed in the middle thereof. .

Incidentally, in a system where the water pump 7 outlet temperature is relatively low, the above 13 subradiators are not particularly required. Alternatively, cooling fins may be attached to the piping downstream of the subradiator 13 to cope with the problem.

At least in the high load region after warm-up of the engine, a first intake air heating cooling water passage 11Fi is connected to the intake pipe 3 (intake air heating section) side at the merging section, while a second intake air heating A control valve device 14 is provided to switch and control the cooling water passages so that the cooling water passages 12 are in communication with each other.

This control valve device 14 includes two substantially cylindrical valve bodies 19 and 20 that move up and down in the figure in a valve housing 15 to cut off communication between three boats 16 to 18't, and these two valve bodies. 19, 20t - a diaphragm device 22 as an actuator to which a rod 21 that is integrally connected is connected.

Among the three boats mentioned above, the boat 16 has the first intake air heating cooling water passage 11 on the radiator inlet passage 4 side.
Next, the first intake air heating cooling water passage 11 on the side of the intake pipe 3 is connected to the boat 17, and finally the second intake air heating cooling water passage 12 is connected to the boat 18.

A pressure chamber 2 defined by the diaphragm device 22Fi and the diaphragm 23 that moves together with the rod 21 described above.
4 is communicated with an intake passage downstream of a throttle valve (not shown) via a pressure signal passage 25, and responds to the intake negative pressure of the engine.

When the suction negative pressure led to the pressure chamber 24 is high,
The tire flam 23 moves upward in the figure against the return spring 26, and the prad 21 and valve body 1 integrated therewith
9 and 20 also move in the same direction so that the boats 16 and 17 communicate with each other through the valve housing 15, while the boat 1g is connected to the valve body 2.
o is blocked.

On the other hand, when the suction negative pressure weakens, the diaphragm 23 is moved downward in the figure by the return spring 26, and the rod 21 and valve body 19°20, which are integral with it, also move in the same direction, and now in the opposite direction. While the boat 16 is blocked by the valve body 19, the boats 17 and 18 communicate with each other via the valve housing 15i. 27 in the figure indicates an atmospheric pressure chamber.

Furthermore, a check pulp 28 is provided in the middle of the pressure signal passage 25, which conducts the passage 25 when the differential pressure across the passage is equal to or higher than a certain value.
A bypass passage 29 is provided to bypass the engine cooling water, and a pan-metal type temperature-sensitive valve 30 is provided in the bypass passage 29 to detect the temperature of the engine cooling water and control the passage 29 to be normally open when the temperature is above a predetermined value. It will be done.

The above check pulp 28 is connected to the leaf spring 31. It consists of a rubber pulp 32 and a plurality of small holes 33, and also has a temperature-sensitive valve a.
A normal one consisting of a bimetal 36 and a leaf spring 37 that connect and disconnect the OFi negative pressure ports 34 and 35t is used.

The rest of the structure is the same as in FIG. 1, so the same members as in FIG. 1 are given the same reference numerals and detailed explanations will be omitted.

Due to this configuration, when the engine is warmed up and the cooling water temperature is low, the bimetal 36 of the temperature-sensitive valve 30 in FIG. is blocked.

Therefore, only when the suction negative pressure of the negative pressure source is higher than the set value, the rubber pulp 32 of the check pulp 28 is bent to the right, and strong negative pressure is transmitted through the small hole 33 and through the pressure signal passage 25 to the pressure chamber of the diaphragm device 22. Guided by 24.

As a result, the valve bodies 19 and 20, which move integrally through the diaphragm 23 and the rod 21, move upward in the figure as described above, communicating the boats 16 and 17, and the one port 18'f
:Cut off.

As a result, only the first intake air heating cooling water passage 11 on the radiator inlet passage 4 side is in communication with the first intake air heating cooling water passage 11 on the intake pipe 3 (intake air heating section) side in FIG. , A large amount of cooling hot water that has been heated by cooling the engine (in other words, heat exchanged) is always supplied to the intake air heating section (the capacity of the intake air heating section is set in advance in this way). Therefore, fuel atomization due to intake air heating is promoted and fuel efficiency in the partial load range is improved.

Next, when the engine cooling water temperature exceeds the set temperature of the bimetal 36 of the temperature-sensitive valve 3° in FIG. Ru.

As a result, a negative pressure corresponding to the suction negative pressure is introduced to the pressure chambers of the diaphragm device 22 through the pressure signal passage 25 and the bypass passage 29t, regardless of the check valve 28.

For this reason, the pressure chamber 2 is
As the negative pressure inside 4 also weakens, the valve bodies 19 and 2, which move integrally through the diaphragm 23 and the rod 21, as described above.
0 moves downward in the figure to cut off port 16t- while allowing communication between boats 17 and 18.

As a result, the first intake air heating cooling water passage 1 on the intake pipe 3 side
1, only the second intake air heating cooling water passage 12 is communicated this time, and relatively low temperature cooling water cooled by the subradiator 13 is supplied to the intake air heating section. The engine is cooled to prevent knocking, and the direction of exit from the relevant operating range is measured.

In other words, even in the operating range, a large amount of high-temperature cooling water flowing through the first intake air heating cooling water passage 11 branched from the upstream side of the radiator 5 is supplied to the intake air heating section, as in the conventional example.
This prevents knocking from occurring due to excessive heating of the intake air.

Next, FIG. 4 is a detailed sectional view of a main part showing a second embodiment of the present invention.

In the control valve device 14 shown in FIG. 3, a wax type temperature sensing valve 4 which also responds to the cooling water temperature is used instead of the bimetal type temperature sensing valve 30 provided in the bypass passage 29.
This is an example in which the lowering limit position of the rod 21 is regulated in accordance with the cooling water temperature to enable more detailed control.

That is, when the temperature of the cooling water passing through the cooling water passage 41 of the temperature-sensitive valve 40 is low, the wax 42 is contracted, so the screws)
y43, the guide 44 is integrally pressed by the spring 45 and is in the position shown in the figure. Therefore, the rod 21 and the valve body 19
, 20 are in the position shown in the figure regardless of the negative pressure value of the pressure chamber 24, and communicate the boats 16 and 17 to heat the intake pipe 3.

Next, as the cooling water temperature mentioned above rises, the wax 42
gradually begins to expand, and the piston 43 and guide 44 begin to descend. Therefore, the rod 21 and the valve bodies 19, 20 are
When the negative pressure value introduced into the pressure chamber 24 is small (that is, in a high load region), it becomes possible to descend to the position regulated by the guide 44, reducing the opening area of the boat 16 while
The total opening area of the intake pipe 8 is increased, and the temperature of the cooling water introduced into the intake pipe 3 is controlled to be low, thereby preventing the occurrence of knocking.

Further, FIGS. 5 and 6 are schematic configurations and detailed cross-sectional views of essential parts showing a third embodiment of the present invention.

This is the second intake air heating cooling water passage 1 in FIG.
The upstream end of the cooling water passage 2 is branched from the middle of the cooling water passage 9 which is a return water passage after heating the intake air, and an electric pump 50 is interposed in this passage 12 in addition to a subradiator 13, and the passage 12 is connected to the main cooling system. This is a completely independent example.

To this end, the control valve device 14 includes another valve body 51 coupled to the rod 21 that shuts off the cooling water passage 9 when the cooling water in the second intake air heating cooling water passage 12 circulates in the intake air heating section. Ru. In the figure, 52 and 53 are boats to which each end of the cooling water channel 9 is connected. Furthermore, the diaphragm device 2
In the atmospheric pressure chamber 27 of No. 2, a movable contact 54 constituting a drive switch for the electric pump 50 described above is located on the diaphragm 23 side, and a fixed contact 55 is provided on the casing side. Therefore, the electric pump 50 operates when the diaphragm 23 is lowered to the lowest level after the engine absorbs material, which will be described later.

Further, in this embodiment, in the middle of the pressure signal path 25.

A bimetal type temperature-sensitive switching valve 56 is provided in series with the check valve 28 to detect the temperature of the engine cooling water and to open the passage 25 to the atmosphere when the temperature exceeds a predetermined value.

This temperature-sensitive switching valve 56 includes a bimetal 57 and a bimetal 5
7, a valve 58 which is interlocked with all shaft valves, and the valve 5
A normal one consisting of an air vent 59 that opens and closes 84C, a leaf spring 60, etc. is used.

Therefore, in this embodiment, after the engine warms up, the pressure chamber S is forcibly released to the atmosphere regardless of the load condition, so the rod 21
Then, the valve bodies 19 and 20 are lowered to the lowest position, and the low-temperature cooling water from the second intake air heating cooling water passage 12 is supplied to the intake air heating section as described above. Of course, at this time, the cooling water channel 9 is shut off by the valve body 51, and the drive switch (movable contact 54 and fixed contact 55) in the atmospheric pressure chamber 27 is turned on to operate the electric pump 50.

Finally, FIG. 7 is a detailed sectional view of a main part showing a fourth embodiment of the present invention.

This corresponds to the pressure chamber 24t of the control valve device 14 in FIG.
- A diaphragm that communicates with the intake passage downstream of the throttle valve (not shown) through the check valve 28t and the pressure signal passages 2 and 5t that are simply installed, while opening the pressure chamber 24 to the atmosphere as necessary. A type atmosphere release valve 61 is integrally incorporated into the upper part of the diaphragm device 22, and this atmosphere release valve 6
1 pressure chamber 62, another check pulp 28' having the same structure as the check pulp 28 interposed in the pressure signal passage 25 in the middle thereof, and a temperature-sensitive valve 30 in FIG. 3 are provided in parallel. This is an example in which the signal passage 67t is communicated with the intake passage downstream of the throttle valve in the same manner as the pressure chamber 24 described above to obtain the same effect as in FIG. 6. Visit,
In this embodiment, nine examples are shown in which the pressure signal passage 67 is branched from the other pressure signal passage 25 upstream of the check valve 28.

That is, after the engine warms up, the cooling water temperature rises and the temperature sensing valve 30
When the valve is opened, a negative pressure value corresponding to the suction negative pressure acts on the pressure chamber 62 of the atmosphere release valve 61 via the pressure signal passage 67 regardless of the check pulp 28'.

Therefore, when the negative pressure value weakens in a high load range, the diaphragm 63 is moved downward in the figure by the force of the spring 64, and the valve body 63 moves integrally with the diaphragm 63.
5 also descends.

As a result, the pressure chamber 24 of the diaphragm device 22, whose strong negative pressure was locked by the check pulp 28, communicates with the atmospheric chamber 66 of the atmospheric release valve 61 and is released to the atmosphere.

As a result, the rod 21, valve bodies 19, 20, etc. are lowered to the lowest position, and the cooling water in the second intake air heating cooling water passage 12 is supplied to the above-mentioned four intake air heating parts, thereby preventing knocking during the operation. This prevents the occurrence of

On the other hand, in the partial load region during warm-up, strong negative pressure acts on the two pressure chambers 62, 24 mentioned above, and the rod 21, valve bodies 19, 20, etc. are restricted to the raised position, and the intake air heating section is Cooling water of 11 yen is supplied to the first intake air heating cooling water passage to heat the intake air.

(Effects of the Invention) As explained above, according to the present invention, a coolant having a lower temperature than the coolant in the first intake air heating coolant passage that branches from the upstream side of the radiator and reaches the intake air heating part is provided in the middle of the first intake air heating coolant passage. flows into the second intake air heating coolant passage, and the first intake air heating coolant passage is cut off from the intake air heating section side at least in the high load region after warming up the engine. On the other hand, we installed a control valve device that switches and controls the coolant passage so that the second intake air heating coolant passage communicates with the second intake air heating coolant passage, thereby preventing engine knocking in the high load range near the end of engine warm-up. The effect can be achieved by further strengthening intake air heating during warm-up and significantly improving fuel efficiency.

[Brief explanation of drawings]

Figure 1 is a schematic diagram of the conventional example, and Figure 2 is the first diagram of the present invention.
3 is a detailed sectional view of the main part thereof, FIG. 4 is a detailed sectional view of the main part of the second embodiment of the present invention, and FIG. 5 is a schematic diagram of the third embodiment. , FIG. 6 is a detailed sectional view of the main part thereof, and FIG. 7 is a detailed sectional view of the main part of the fourth embodiment of the present invention. 1... Cylinder block, 2... Cylinder head,
3... Intake pipe, 5... Radiator, 7... Water pump, 11... First intake air heating coolant passage, 1
2... First cooling liquid passage for heating intake air, 13... Subradiator, 14... Control valve device. Patent applicant Nissan Motor Co., Ltd. Figure 1 q Figure 2

Claims (1)

[Claims] In a liquid-cooled internal combustion engine that is equipped with a radiator that cools engine coolant and that directs the coolant branched from upstream of the radiator to an intake air heating section that heats intake air or air-fuel mixture, the engine coolant is branched from upstream of the radiator to heat the intake air. In the middle of the first intake air heating coolant passage leading to the first intake air heating coolant passage, a second intake air heating coolant passage through which a coolant having a lower temperature than that of the coolant in the passage flows is joined, and at least the engine warming-up passage is connected to the second intake air heating coolant passage. In the later high load range, the first intake air heating coolant passage is shut off from the intake air heating section side, and the second intake air heating coolant passage is connected to the intake air heating section side by switching control. An intake air heating device for an internal combustion engine, characterized in that it is provided with a control valve device.