JP3367288B2 - Intake device for internal combustion engine - Google Patents

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake system for an internal combustion engine, and more particularly to generating a swirl in a combustion chamber,
The present invention relates to a technique for improving combustibility by using an auxiliary air intake port that is installed side by side with a main air intake port of a cylinder head.

2. Description of the Related Art A conventional intake device for an internal combustion engine having a sub intake port provided in parallel with a main intake port of a cylinder head for generating a swirl flow in a combustion chamber is a sub intake port for forming a drift (Hereinafter, referred to as a tubular auxiliary intake port) is disclosed in JP-A-55-25546.
JP-A No. 61-167122 and the like. In the manufacturing process, the intake device with this tubular auxiliary intake port requires post-processing such as drilling in order to drill the auxiliary intake port, and the auxiliary intake port moves inside the water gallery in the cylinder head. Since it passes through, the cooling performance may decrease. Further, in a fuel injection type intake device that injects fuel into the main intake port, it is necessary to accurately inject fuel into the outlet of the auxiliary intake port, but in reality, the injected fuel diffuses and the auxiliary intake It may be injected into a portion other than the port outlet, and this may become a wall flow, which may be sucked into the combustion chamber as it is and deteriorate emission and lean performance. In addition to this, actual development Sho 59-1945
As disclosed in Japanese Patent No. 33, 33, one having a sub-intake port for drift formation (hereinafter, referred to as a groove-shaped sub-intake port) composed of a concave groove that eliminates the drawbacks of the tubular sub-intake port is also considered. It was

However, since the intake system of the internal combustion engine having the above-described groove-shaped auxiliary intake port is configured to open and close only the main intake port by the intake branch valve, Since the cross-sectional area of the intake passage is constant and the flow velocity control range of the unbalanced flow, that is, the control range of the tumble ratio is narrow, the expansion of the low fuel consumption region (lean region) by strengthening the tumble swirl flow could not be expected more than at present. Therefore, in view of the above conventional problems, it is an object of the present invention to improve combustion by changing the intake passage cross-sectional area of the auxiliary intake port to expand the control range of the tumble ratio.

Therefore, according to the invention of claim 1, the intake air of the internal combustion engine having the auxiliary intake port for forming a drift is formed from the groove to the downstream side from the vicinity of the inlet portion of the main intake port of the cylinder head. In the device, a first intake flow dividing valve that opens and closes the main intake port and a second intake flow dividing valve that opens and closes the auxiliary intake port are provided in the vicinity of the inlet portion of the main intake port, and depending on an engine operating state. Since the control means for controlling the opening and closing of each of the first intake air flow dividing valve and the second intake air flow dividing valve is included, the intake flow passage cross-sectional area of the auxiliary air intake port changes, and the flow velocity of the drift is controlled. According to a second aspect of the present invention, in an intake system for an internal combustion engine having an auxiliary intake port for forming a drift formed of a concave groove in the downstream side from the vicinity of the main intake port inlet of the cylinder head, in the vicinity of the inlet of the main intake port. An intake diversion valve that opens and closes the main intake port, and a protrusion that opens and closes the sub intake port is connected to the valve body of the intake diversion valve to control the opening and closing of the intake diversion valve according to the engine operating state. Since it is configured to include control means,
The cross-sectional area of the intake flow passage of the auxiliary intake port changes, and the flow velocity of the drift is controlled. According to a third aspect of the present invention, the auxiliary intake port is formed in a generally constant flow passage cross-sectional shape throughout, and the intake flow is directed from the intake valve gap directly into the combustion chamber when the intake valve is lifted. Therefore, the diffusion of the drift is suppressed as much as possible.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. 1 to 3 show an intake system for an internal combustion engine according to an embodiment of the present invention. The intake device has two main intakes that branch from a single intake passage 2 provided corresponding to each combustion chamber (cylinder) 1 and communicate with the same combustion chamber 1 via intake valves 3a and 3b, respectively. Ports 4a and 4b are provided. At the bottoms of the main intake ports 4a, 4b, from the vicinity of the inlets of the main intake ports 4a, 4b, the intermediate parts of the intake valves 3a, 3b and the intake port partitioning part 6 are directed, and the whole is substantially constant. The auxiliary intake ports 5a and 5b for forming a non-uniform flow, which are concave grooves formed in the flow channel cross-sectional shape, are provided. The auxiliary intake ports 5a, 5b generate a tumble swirl flow (longitudinal swirl flow) 7 that is as strong as possible, so that the intake flow is directly introduced into the combustion chamber 1 through the valve clearance when the intake valves 3a, 3b are lifted. It is formed so as to be oriented in any direction. Further, the intake passage 2 is provided with a first intake flow dividing valve 8 that opens and closes the main intake ports 4a and 4b, and a second intake flow dividing valve 9 that opens and closes the auxiliary intake ports 5a and 5b. The first intake air flow dividing valve 8 has an actuator 10a that opens and closes the valve body 8a by rotating the valve body mounting shaft 8b via the valve body mounting shaft 8b.
It is connected to the. In the second intake diversion valve 9, the valve bodies 9a and 9b are connected via a valve body mounting shaft 9c,
By rotating the valve body mounting shaft 9c, the valve bodies 9a, 9
It is configured to be connected to an actuator 10b that opens and closes b. The actuators 10a, 10b
Is driven and controlled by a control unit F having a function of a control means described later according to the operating state based on the engine speed and the engine load (intake flow rate), and the first intake flow dividing valve 8 and the second intake flow dividing valve 9 are Each is opened and closed independently. When the first intake air flow dividing valve 8 is closed, the main intake ports 4a, 4b are closed, and most of the intake air flowing through the intake passage 2 passes through the auxiliary intake ports 5a, 5b. Further, the second intake diversion valve 9 is provided in the auxiliary intake port 5
The flow passage cross-sectional areas of a and 5b are increased / decreased so that the auxiliary intake ports 5a and 5a
The flow velocity of the uneven flow in b is changed. In this embodiment, the auxiliary intake ports 5a and 5b are connected to the intake valves 3
Although they are provided independently for each of a and 3b, this may be used as a sub-intake port for forming a non-uniform flow formed of a single groove. here,
An outline of control of the intake system of the internal combustion engine by the control unit F will be described with reference to FIG. The outputs of the rotation sensor A and the load sensor B, which detect the engine speed and the load as the engine operating state, are input to the control means D via the input means C, respectively. The output of the control means D is output to the actuators 10a and 10b via the output means E, respectively. The control means D determines the control contents of the intake device based on the engine operating state, and the actuators 10a and 10b.
The intake device is controlled by driving and controlling Next, the details of the operation of the intake device for the internal combustion engine under the control will be described in detail below. When the first intake diversion valve 8 is closed in order to strengthen the tumble swirl flow 7 in the combustion chamber 1, most of the intake air flowing in the intake passage 2 is sub-intake port 5a,
It will pass 5b. In this case, the drift in the auxiliary intake ports 5a and 5b is directly sucked into the combustion chamber 1 through the intake valve clearance because the flow velocity of the drift is suppressed as much as possible by the groove. When the second intake air distribution valve 9 is closed while the first intake air distribution valve 8 is closed, the flow passage cross-sectional areas of the auxiliary intake ports 5a and 5b gradually decrease, and as a result, the drift increases its flow velocity. . Therefore, the tumble swirl flow 7 in the combustion chamber 1 is
It is strengthened more than when the intake branch valve 8 is closed. here,
FIG. 10 shows experimental data showing how the tumble ratio changes by opening and closing the second intake air flow dividing valve 9. As a result of the above operation, the intake passage 2 (== in the present embodiment, which changes depending on the opening and closing of the first intake flow dividing valve 8 and the second intake flow dividing valve 9
FIG. 8 shows the relationship between the opening ratio of the main intake port + the auxiliary intake port (= diversion valve gap area / passage cross-sectional area) and the tumble ratio. First intake flow dividing valve 8 and second intake flow dividing valve 9
However, when both are in the fully open state, the standard (aperture ratio 100%,
A change in the aperture ratio and the tumble ratio will be described assuming that the tumble ratio is 1). If only the first intake flow dividing valve 8 is closed from this state, the flow passage cross-sectional areas of the main intake ports 4a and 4b decrease, and the opening ratio becomes about 15% in the fully closed state. As the opening ratio decreases, the proportion of intake air that passes through the auxiliary intake ports 5a and 5b increases, so that a drift occurs in the auxiliary intake ports 5a and 5b, causing a tumble swirl flow. For this reason,
The tumble ratio increases to about 1-3. When only the second intake flow dividing valve 9 is closed while the first intake flow dividing valve 8 is in the fully closed state, the flow passage cross-sectional areas of the auxiliary intake ports 5a and 5b are further reduced, and the opening ratio is approximately in the fully closed state. It will be about 5%. As the opening ratio decreases, the uneven flow in the auxiliary intake ports 5a and 5b further intensifies the flow velocity, so that the tumble swirl flow further intensifies and the tumble ratio increases to about 5. However, if the tumble ratio is increased, the cycle fluctuation, that is, the stability of the engine is reduced. Therefore, in the region of low rotation and low load (including idle time), the first intake diversion valve 8 and the second intake diversion valve It is not desirable to fully close 9 together. Further, in the medium speed / high load range, if the opening ratio is made too small, the intake flow rate decreases and the axial torque does not occur. Therefore, in this case as well, the second intake diversion valve 9 must be opened. In consideration of the above, the first intake flow dividing valve 8 and the second intake flow dividing valve 9
The control contents of are summarized in FIG. By the way, in the embodiment described above, the first intake flow dividing valve 8 and the second intake flow dividing valve 9 are used to change the opening ratio of the intake passage 2.
5 is used together, another embodiment in which this is simplified and the opening ratio is changed by one intake shunt valve is shown in FIG.
7 to 7 and will be described in detail below. This replaces the first intake diversion valve 8 and the second intake diversion valve 9, instead of the main intake port 4
a, 4b and the auxiliary intake ports 5a, 5b are opened and closed by a single intake diversion valve 11. The intake flow dividing valve 11 includes a valve body 11a that opens and closes the main intake ports 4a and 4b, and projection portions 11b and 1b that reduce flow passage cross-sectional areas of the auxiliary intake ports 5a and 5b as the valve body 11a closes.
The valve body 1a connecting the 1c is rotated by the valve body mounting shaft 11d via the valve body mounting shaft 11d.
It is connected to an actuator 10c that opens and closes 1a. The actuator 10c is drive-controlled by the control unit F described above according to the operating state based on the engine speed and the engine load (intake flow rate), and the intake flow dividing valve 11 is opened and closed. In such a configuration, the intake diversion valve 11 has the main intake ports 4a, 4b.
In addition to the opening / closing control of the above, the angle control must be accurately performed in order to control the opening / closing of the auxiliary intake ports 5a, 5b by the single actuator 10c. In this case, depending on the turning angle of the actuator 10c, the main intake ports 4a, 4
b is open and auxiliary intake ports 5a and 5b are open, main intake ports 4a and 4b are closed and auxiliary intake ports 5a and 5b
Considering three states in which b is an open state, main intake ports 4a and 4b are closed states, and auxiliary intake ports 5a and 5b are closed states, this is the same as the control content in the above-described embodiment in FIG. , A similar effect is obtained. further,
According to this embodiment, since the intake device is controlled only by the single intake shunt valve 11, the number of constituent parts such as actuators to be used is reduced.
The control becomes simple and the cost can be reduced.
It should be noted that, as in each of the above-described embodiments, the intake device having the auxiliary intake port for forming the non-uniform flow formed of the concave groove (hereinafter, referred to as the groove-shaped auxiliary intake port) is an auxiliary intake device for forming the non-uniform flow formed of the conventional pipe. Port (hereinafter referred to as a pipe-shaped auxiliary intake port)
There are the following effects (advantages) as compared with those having.
In the case of the tubular auxiliary intake port, the auxiliary intake port having the length L ′ (L ≠ L ′) is arranged in parallel with the main intake port having the length L. Even when performing output improvement matching at a predetermined rotation speed,
An untuned component of L'is generated, which causes a reduction in output. On the other hand, in the case of the groove-shaped auxiliary intake port, the problem of output reduction does not occur because no misalignment occurs. In addition, since the groove-shaped auxiliary intake port has a smaller intake resistance for one surface corresponding to the wall of the pipe compared to the pipe-shaped auxiliary intake port, the flow passage area is small when the same amount of intake air flows, that is, ,
Can be made compact. In addition, when a groove-shaped or pipe-shaped auxiliary intake port is formed by casting, the groove-shaped auxiliary intake port can be handled only by changing the shape of the core. Alternatively, additional machining is required. That is, in the case of the tubular auxiliary intake port, the manufacturing cost is increased.

As described above, according to the first aspect of the present invention, the second intake branch valve for opening and closing the auxiliary intake port changes the intake passage cross-sectional area of the auxiliary intake port, which causes uneven flow. Since the flow velocity is controlled, the control range of the tumble ratio is widened, and the low fuel consumption region (lean region) can be widened. According to the invention as set forth in claim 2, since the projection portion for opening and closing the auxiliary intake port has the effect of the invention as set forth in claim 1, the structure and control of the intake device are simplified, so that the cost of the intake device is reduced. Can be achieved. According to the third aspect of the invention, the uneven flow flowing through the auxiliary intake port directly flows into the combustion chamber through the intake valve gaps, so that the diffusion of the uneven flow is suppressed as much as possible. Therefore, the tumble swirl flow generated in each combustion chamber is suppressed. Can be strengthened.

[Brief description of drawings]

FIG. 1 is a plan sectional view showing an embodiment of the present invention.

FIG. 2 is a front sectional view of the same embodiment as above.

FIG. 3 is a view showing a cross section AA in FIG. 1 of the above embodiment.

FIG. 4 is a control block diagram showing an outline of control of the embodiment.

FIG. 5 is a plan sectional view showing another embodiment of the present invention.

FIG. 6 is a front sectional view of the above embodiment.

FIG. 7 is a view showing a cross section BB in FIG. 5 of the above embodiment.

FIG. 8 is a diagram showing the relationship between the aperture ratio and the tumble ratio in one embodiment of the present invention.

FIG. 9 is a diagram showing one control content of the intake flow dividing valve in the embodiment.

[Fig. 10] Experimental data of the opening degree and the tumble ratio of the second intake diversion valve in the above embodiment

[Explanation of symbols]

4a, 4b Main intake port 5a, 5b Secondary intake port 8 First intake diversion valve 8a valve body 9 Second intake shunt valve 9a, 9b valve body 11 Intake shunt valve 11a valve body 11b, 11c protrusion A rotation sensor B load sensor F control unit

Claims (3)

(57) [Claims] 1. An intake system for an internal combustion engine, comprising an auxiliary intake port for forming a drift, which is a concave groove extending downstream from the vicinity of the inlet of the main intake port of a cylinder head. First to open and close the intake port
An intake air flow dividing valve and a second intake air flow dividing valve that opens and closes the auxiliary air intake port are included, and a control unit that controls opening and closing of the first intake air flow dividing valve and the second intake air flow dividing valve in accordance with an engine operating state is included. An intake system for an internal combustion engine, characterized in that it is configured. 2. An intake system for an internal combustion engine having a sub-intake port for forming a non-uniform flow, which is formed by a groove extending from the vicinity of the inlet of the main intake port of the cylinder head to the downstream side thereof. A control unit is provided which has an intake diversion valve that opens and closes the intake port, connects the valve body of the intake diversion valve with a protrusion that opens and closes the auxiliary intake port, and controls the opening and closing of the intake diversion valve according to the engine operating state. An intake device for an internal combustion engine, which is configured to include the above. 3. The auxiliary intake port is formed in a generally constant flow passage cross-sectional shape throughout, and is directed in a direction in which an intake flow directly flows into a combustion chamber from an intake valve gap when the intake valve is lifted. The intake system for an internal combustion engine according to claim 1 or 2.