JPS6118011B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intake system for an engine, and particularly to an intake system in which an intake passage near a combustion chamber is divided into a primary intake passage and a secondary intake passage.

Generally, in an engine, as the intake flow rate increases, the atomization of fuel in the intake pipe is promoted, swirl is generated in the combustion chamber, and the combustion speed increases, resulting in good combustion and combustion efficiency. is known to improve.

Therefore, as an engine intake system that improves combustion efficiency, the intake passage near the combustion chamber is divided into a primary side intake passage and a secondary side intake passage, and when the amount of intake air is small, the intake passage on the primary side Some devices supply intake air only from the intake passage, but when the amount of intake air is large, they switch to supply intake air from the secondary intake passage in addition to the above-mentioned primary intake passage (for example, Japanese Patent Laid-Open No. 55 -Refer to Publication No. 14957).

However, in such a device, especially when intake air is supplied only from the primary intake passage when the engine is warm, the combustion speed becomes too fast as the amount of intake air increases, leading to abnormal combustion, that is, rapid combustion. There is a risk that combustion noise may be generated due to combustion.

Additionally, if the intake air velocity becomes too high, when it enters the combustion chamber, it tends to collide with the combustion chamber wall, which absorbs the amount of heat and raises the temperature of the air-fuel mixture, making it more likely to cause knocking. There is also.

Furthermore, if an operating range is set in which intake air is supplied only from the primary intake passage in order to prevent abnormal combustion and knocking during warm conditions, combustion efficiency cannot be sufficiently improved during cold conditions when combustibility is relatively poor. There is a problem.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an intake system for an engine that improves combustibility in cold conditions and improves overall combustion efficiency without causing abnormal combustion or knocking. shall be.

In order to achieve the above object, the present invention has been made by focusing on the fact that the combustibility of the engine is worse when the engine is cold than when it is warm. When the amount of intake air is small, the supply of intake air from the secondary side intake passage is restricted and the intake air is supplied from the primary side intake passage, while when the amount of intake air is large, the In an engine intake system that switches to supply intake air from the primary side intake passage in addition to the primary side intake passage, when the engine is cold, the intake air amount is switched to be larger than when the engine is warm, and only the above-mentioned primary side intake passage is supplied. The present invention is characterized by the provision of a control device that expands the operating range in which intake air is supplied from the intake air.

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

<Example 1> In FIG. 1, 1 is an intake passage, the downstream end of which is a cylinder block 3 in which a piston 2 moves up and down.
An intake port 7 that is opened and closed by an intake valve 6 is connected to a combustion chamber 5 formed by joining the cylinder head 4 and the cylinder head 4.
connected via. This intake passage 1 is a partition wall provided only downstream of a main throttle valve 9 (linked to an accelerator pedal, not shown) disposed downstream of a vent lily portion 8 and in the vicinity of a combustion chamber 5. At 10, it is divided into a primary side intake passage 11 having a relatively small passage area and a secondary side intake passage 12 having a relatively large passage area.

A sub-throttle valve 13 is rotatably provided in the upstream portion of the secondary intake passage 12 .
The auxiliary throttle valve 13 has a rotating shaft 13a mechanically connected to a diaphragm device 16 via a connecting rod 14 and a connecting rod 15, and opens and closes the secondary intake passage 12 by the operation of the diaphragm device 16. It is composed of

In the diaphragm device 16, a casing 16a is connected to an atmospheric chamber 16c and a negative pressure chamber 1 by a diaphragm 16b.
6d, and is attached so that the diaphragm 16b is always deflected upward by a spring 16e compressed in the negative pressure chamber 16d, that is, the sub-throttle valve 13 closes the secondary intake passage 12. Forced.

17 is a negative pressure introduction passage, and a diaphragm device 16
The negative pressure chamber 16d and the negative pressure outlet 8a of the bench lily portion 8 of the intake passage 1 are communicated with each other.

Reference numeral 18 denotes an atmosphere opening passage in which an orifice 19 is interposed, which branches off from the middle of the negative pressure introduction passage 17. The downstream end opening 18a of this atmosphere opening passage 18
is controlled to open and close as appropriate by the valve body 20a of the solenoid valve 20.

Reference numeral 21 denotes a temperature sensor, which is installed so as to face the cooling water passage 22 in the cylinder block 3 and detects the temperature of the cooling water. This temperature sensor 21
is the solenoid valve 2 via the control circuit 23.
0, whereby the control circuit 23 is configured to control the operation of the solenoid valve 20 in response to a signal from the temperature sensor 21.

Note that 24 is an exhaust passage, which is connected to the combustion chamber 5 through an exhaust port 26 whose opening and closing are controlled by an exhaust valve 25 . 27 is the camshaft, 28,2
9 is the rock arm, 30 and 31 are the valve guides,
32 and 33 are springs, and 34 is a main nozzle.

If configured as above, for example, the cooling water temperature
When the temperature exceeds 40° C., the temperature sensor 21 detects that the temperature is in the warm state, and a warm signal is input to the control circuit 23. As a result, a closing signal is output from the control circuit 23 to the solenoid valve 20 to close the opening 18a of the atmosphere opening passage 18, so that the vent lily negative pressure is introduced into the negative pressure chamber 16d of the diaphragm device 16. As a result, in response to the negative pressure in the bench lily, the diaphragm 16b is deflected downward against the elastic force of the spring 16e, the sub-throttle valve 13 is rotated, and the secondary intake passage 1 is rotated.
Open 2.

In this way, the amount of intake air supplied through the secondary intake passage 12 is controlled according to the bench lily negative pressure, which has a correlation with the amount of intake air, and the intake flow rate is increased to the extent that abnormal combustion and knocking do not occur. This promotes fuel atomization and improves combustibility.

On the other hand, when the cooling water temperature is 40° C. or lower, for example, the temperature sensor 21 detects that the system is in a cold state, and a cold state signal is input to the control circuit 23 . As a result, the control circuit 23 outputs an opening signal to the solenoid valve 20 to open the opening 18a of the atmosphere opening passage 18, so that the negative pressure introduction passage 17 is opened to the atmosphere through the atmosphere opening passage 18. . As a result, a portion of the bench lily negative pressure will be released to the atmosphere, so
Unless the diaphragm 16b becomes larger to a certain extent than when it is warm, the diaphragm 16b will not deviate and the sub-throttle valve 13 will not rotate, so the secondary intake passage 12 will not be opened and the primary intake Intake air is supplied only from the passage 11.

In this way, the operating range of only the primary side intake passage 11 is expanded during cold conditions compared to when warm conditions (second
(see figure).

As mentioned above, since the operating range in which intake air is supplied only from the primary side intake passage 11 during cold times when combustibility is worse than during warm times, abnormal combustion does not occur and the cold time This promotes atomization, improves combustibility, and improves overall combustion efficiency.

<Example 2> In FIG. 3, an intake passage 41 is connected to a primary side intake passage 42 and a partition wall 44 formed from the bench lily portions 45 and 46 to the vicinity of the combustion chamber 5.
It is divided into a next side intake passage 43. On the downstream side of the bench lily portion 45 of the primary side intake passage 42, there is a primary side throttle valve 47 as a main throttle valve linked to the accelerator pedal, and on the downstream side of the bench lily portion 46 of the secondary side intake passage. Example 1>
Similarly to the secondary throttle valves 48, secondary throttle valves 48 are provided as secondary throttle valves whose opening and closing are controlled by the vent valve negative pressure of the primary intake passage 42.

Since the other components are the same as those in Example 1, the same reference numerals are used for the similar components, and detailed explanation thereof will be omitted.

According to the above configuration, as in the case of <Embodiment 1>, the vent lily negative pressure (the negative pressure generated in the vent lily portion 45 of the primary side intake passage 42) that controls the operation of the diaphragm device 16 is At times, a portion of the intake passage 4 is exposed to the atmosphere through the atmosphere opening passage 18, so that the primary side intake passage 4 is more open when it is cold than when it is warm.
The operating range of only No. 2 is expanded, the combustibility during cold conditions is improved, and the overall combustion efficiency is improved.

In Embodiment 1, the interior of one intake pipe is divided by a partition wall to form the primary and secondary intake passages, but the intake pipe itself is branched midway to form the primary and secondary intake passages. A next-side intake passage may also be formed. In that case, it goes without saying that the main throttle valve is disposed upstream of the branch point, and the auxiliary throttle valve is disposed in the secondary intake passage downstream of the branch point.

In each of the above embodiments, control is performed by changing the bench lily negative pressure introduced into the negative pressure chamber 16d of the diaphragm device 16 during warm and cold times. It can also be controlled by changing the spring constant of the spring 16e in the negative pressure chamber 16d of the device 16.

As described above, the present invention is configured to expand the operating range of only the primary side intake passage when cold in an engine intake system having a primary side intake passage and a secondary side intake passage near the combustion chamber. Therefore, it is possible to improve the combustibility during the cold state without causing abnormal combustion during the warm state, and has the excellent effect of improving the combustion efficiency as a whole.

[Brief explanation of the drawing]

Fig. 1 is an overall configuration diagram of the engine intake system of Embodiment 1, and Fig. 2 is a diagram showing the configuration of the intake system of the engine in Embodiment 1.
FIG. 3 is an explanatory diagram showing the relationship between the operating areas of the next-side and secondary-side intake passages, and FIG. 3 is an overall configuration diagram of an engine intake system according to a second embodiment. DESCRIPTION OF SYMBOLS 1... Intake passage, 5... Combustion chamber, 9... Main throttle valve, 10... Partition wall, 11... Primary intake passage, 12... Secondary intake passage, 13... Sub-throttle valve , 16... diaphragm device, 1
7...Negative pressure introduction passage, 18...Atmospheric release passage, 1
9... Orifice, 20... Solenoid valve,
21...Temperature sensor, 22...Cooling water passage, 23
...Control circuit, 41...Intake passage, 42...Primary side intake passage, 43...Secondary side intake passage, 44...
Bulkhead, 47... Primary side throttle valve, 48...
...Secondary side throttle valve.

Claims (1)

[Claims] 1. The intake passage near the combustion chamber is called the primary intake passage.
When the amount of intake air is small, the intake air is restricted from the secondary intake passage, and the intake air is supplied from the primary intake passage, while when the amount of intake air is large, In an engine intake system that switches to supply intake air from the secondary intake passage in addition to the primary intake passage, when the engine is cold, the intake air amount is switched to a larger amount than when the engine is warm. An intake system for an engine, characterized in that it is provided with a control device that expands the operating range in which intake air is supplied from only the engine.