JP2524598B2 - Supercharged engine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a supercharged engine, and more particularly to a supercharged engine that promotes scavenging of combustion gas with intake air supplied into a combustion chamber.

<Prior Art> Generally, in an engine with a supercharger, when the supercharging pressure is increased, the overlap amount of the opening timing of the exhaust valve and the intake valve is increased to supply the exhaust gas from the intake port. There is a method in which the combustion gas in the combustion chamber is discharged from the exhaust port with supercharged air to improve the scavenging effect and thereby reduce the residual gas (Japanese Patent Laid-Open No. 61-19933).

That is, by reducing the residual gas in this way, the temperature of the intake air in the combustion chamber is lowered to improve the knock resistance, so that the combustion efficiency is improved by increasing the compression ratio.

However, if it is attempted to sufficiently perform the scavenging with the supercharged air in this manner, a portion of the intake air is inevitably exhausted directly from the exhaust port, so that the fuel mixed in the intake air is also exhausted to the exhaust manifold at the same time.

For this reason, an increase in the low emission, an increase in the exhaust gas temperature due to afterburn, and a deviation in the air-fuel ratio occur.

Therefore, a means for using intake air (only air) in which fuel is not mixed in purging combustion gas in the combustion chamber has been proposed.

That is, this means is provided with two intake ports, one of them is dedicated to supply of the air-fuel mixture, and the other one port is dedicated to supply of only intake air (air). By scavenging the combustion gas with intake air supplied from a dedicated port for intake air only, the fuel discharged to the exhaust manifold can be significantly reduced and the above-mentioned problems can be eliminated.

<< Problems to be Solved by the Invention >> However, as shown in FIG. 12, the intake device 1 of the engine which intends to perform scavenging with only the intake air has a dedicated supply port 2 for the intake air only and a dedicated supply of the air-fuel mixture. The ports 3 are formed in the same direction so as to face the top surface 4a of the piston 4, respectively.

As described above, the exclusive supply port 3 for the air-fuel mixture is directed toward the top surface 4a of the piston 4, so that the filling efficiency is improved. In the intake-only supply port 2, the scavenging effect of the combustion gas is significantly reduced by directing the top surface 4a of the piston 4.

That is, when the intake air supplied from the exclusive supply port 2 for intake air is directed toward the top surface 4a, that is, downward, the inflow energy of the intake air at this time rises in the latter half of the exhaust stroke. There is a problem in that it is canceled by the rising pressure of the piston 4 and the sufficient scavenging effect cannot be obtained.

Therefore, an object of the present invention is to provide an engine with a supercharger capable of performing effective scavenging without being influenced by the rising pressure of the piston by changing the directivity direction of the dedicated intake-only supply port. And

<< Means for Solving the Problems >> In order to achieve such an object, the present invention provides at least one main intake port for supplying an air-fuel mixture and at least one auxiliary intake port for supplying only intake air. An intake control valve that is opened independently in each cylinder and that supplies and shuts off the auxiliary intake port is provided upstream of the auxiliary intake port, and the intake control valve is opened in a predetermined high load operation state to open the auxiliary intake port. Is supplied to the combustion chamber so as to overlap with the valve opening timing of the exhaust port, and the directing direction of the auxiliary intake port to the combustion chamber is substantially vertical to the cylinder axis.

<Operation> In the engine with a supercharger of the present invention having the above-described configuration, since the directing direction of the auxiliary intake port is substantially perpendicular to the cylinder axis, the air supplied from the auxiliary intake port is The inflow energy can be efficiently used for scavenging the combustion gas without being substantially affected by the rising pressure of the piston.

<Example> An example of the present invention will be described in detail below with reference to the drawings.

That is, FIG. 1 and FIG. 2 show an embodiment of the engine 101 with a supercharger of the present invention, in which the intake device 100 of the engine 101 has two intake ports 102a each having an independent opening for each cylinder. , 102b and two exhaust ports 103a, 103b. One of the intake ports 102a, 102b serves as a main intake port and the other intake port 102b serves as a sub intake port.

A supercharger (not shown) is mounted upstream of the intake system of the engine 101, and air pressurized by the operation of the supercharger is supplied to the main intake port 102a and the sub intake port 102b.

Each intake port 102a, 102b and each exhaust port 103a, 103b
Is the intake valve 104a, 104b and the exhaust valve 1 as shown in FIG.
It is opened and closed by 05a and 105b.

The intake valves 104a, 104b and the exhaust valves 105a, 105b are driven by an intake cam 108 and an exhaust cam 109 via hydrolash adjusters 106, 107, respectively.

Inside the branch pipes 111 and 112 of the intake manifold 110, a partition wall 113 is provided in accordance with the two main and auxiliary intake ports 102a and 102b.
Is branched into two branch passages 114 and 115 from the middle.

An injector 117 for fuel injection is provided in the mounting hole 116 formed on the upper side of the one branch passage 114,
The fuel injected from this injector 117 is supplied to the injection passage 1
It is injected into the branch passage 114 via 18 and the injection pipe 119.

In addition, the other branch passage 115 has an intake port 102b.
An intake shutter valve 120 as an intake control valve is provided at a position close to the.

The shutter valve 120 is attached to a valve shaft 121 penetrating the vicinity of the attachment portion of the intake manifold 110, and is opened / closed by rotation of the valve shaft 121.

By the way, by the intake cam 108, the main intake port 1
Intake valves 104a and 104b for opening and closing 02a and the auxiliary intake port 102b
The mutual valve timings of the above are in the relationship shown in FIG.

That is, the main intake port 102a side (primary [P] side) intake valve 104a shown by the solid line in the figure is opened at normal timing, but the auxiliary intake port 102b shown by the broken line in the figure.
The (secondary [S]) side is opened earlier than that,
The amounts L1 and L2 overlapped with the opening timing of the exhaust valves 105a and 105b indicated by the two-dot chain line in the figure are the former P-side intake valve 104a.
The overlap amount L2 of the latter S-side intake valve 104b is larger than the overlap amount L1 of
The opening of 104b starts from the latter half of the opening timing of the exhaust valves 105a and 105b.

Here, in the present embodiment, the branch passage 115 on the side of the auxiliary intake port 102b is gently curved downward as shown in FIG. 2 so that the portion reaching the auxiliary intake port 102b becomes horizontal. Is formed in the auxiliary intake port 102b.
Are oriented substantially perpendicular to the cylinder axis C.

Further, as shown in FIG. 4, the branch passage 115 is formed in a curved shape so that the portion reaching the auxiliary intake port 102b is directed to substantially the central portion between the exhaust ports 103a and 103b in plan view. A portion in which the branch passage 115 is curved in a plan view as described above serves as a drift mechanism 122.

That is, the non-uniform flow means 122 is a means for guiding the main inflow direction of the air supplied from the auxiliary intake port 102b to the combustion chamber 123 to the substantially central portion of the entire exhaust port, and is shown in FIG. 5, for example. As described above, the guide projection 124 may be formed on the inner wall of the combustion chamber 123 in the vicinity of the auxiliary intake port 102b, and the guide projection 124 may be used as the drift means 122.

With the above-described configuration, in the intake device 100 of the present embodiment, the shutter valve 120 is closed and the intake manifold is closed in the low and medium load regions of the engine 101 in which the residual combustion gas in the combustion chamber 123 does not pose a problem. The intake air supplied from 110 is supplied to the main intake port 102a via a branch passage 114 provided with an injector 117.

Therefore, the fuel injected from the injector 117 is mixed with the intake air introduced into the combustion chamber 123 from the main intake port 102a when the intake valve 104a is opened, and the engine 101 is operated by this air-fuel mixture.

Then, in the high load region of the engine 101 where the residual amount of combustion gas is large, the shutter valve 120 is opened, and the intake air of the intake manifold 110 is supplied to the main exhaust port 102a and the auxiliary intake port 102b.

At this time, the intake air supplied to the auxiliary intake port is only the air because the injector is not provided in the branch passage 115, and this air is opened by the intake valve 104b on the S side along the valve timing shown in FIG. And the auxiliary intake port
The fuel is supplied into the fuel chamber 123 from 102b. Since this supply air is pressurized by the supercharger, it is forced into the combustion chamber 123.

Therefore, from the auxiliary intake port 102b to the combustion chamber 123
In the air flowing into the inside of the combustion chamber 123, the combustion gas in the combustion chamber 123 is exhausted from the exhaust ports 103a and 103b because the start of opening the intake valve 104b on the S side is almost the latter half of the opening timing of the exhaust valves 105a and 105b.
Scavenge to.

At the time of scavenging the exhaust gas, in the present embodiment, since the directing direction of the sub intake port 102b is substantially vertical to the cylinder axis C, the air flowing in from the sub intake port 102b is also out of the drawing. The direction is almost perpendicular to the moving direction of the viston, and the combustion gas scavenging can be effectively performed without being affected by the rising pressure of the cylinder in the exhaust stroke and suppressing the energy loss of the inflowing air as much as possible.

In addition, the air supplied from the sub intake port 102b is diffused to some extent in the combustion chamber 123, but
Since the uneven flow means 122 is provided in b, the auxiliary intake port
The air flowing into the combustion chamber 123 from the 102b mainly flows toward the central portion between the exhaust ports 103a and 103b,
In combination with the diffusion of air, the incoming air is
Is supplied to almost the entire area of the combustion chamber, and the scavenging effect of combustion gas is further improved.

Therefore, since the combustion gas in the combustion chamber 123 is almost certainly scavenged by the air flowing in from the auxiliary intake port 102b in this way, the temperature in the combustion chamber 123 is lowered and the knock resistance is improved.

Therefore, the compression ratio of the engine 101 can be further increased, and combustion efficiency, response can be improved, and output can be increased.

In addition, since the scavenging of the combustion gas is mainly performed only by the intake air, that is, only the air, the afterburn is prevented from occurring.

FIG. 6 and FIG. 7 show other embodiments, respectively, with three intake ports. In the embodiment of FIG. 6, the central portion of these intake reports is the auxiliary intake port 102b, and both sides thereof are the main intake ports. Port 102a, and in the embodiment of FIG. 7, both sides are auxiliary intake ports 102b and the central part is the main intake port.
It is as 102a.

Therefore, even in the case where a plurality of main intake ports 102a and sub intake ports 102b are provided,
By pointing each sub intake port 102b in a direction substantially perpendicular to the cylinder axis C and by pointing a substantially central portion between the exhaust ports 103a and 103b, it is possible to obtain the same function as that of the above embodiment.

FIG. 8 and FIG. 9 show still another embodiment, which is a flow diverting means.
122 is a recess 126 formed on the top surface 125a of the piston 125.
It is formed by.

That is, in this embodiment, as shown in FIG. 9, the recess 126 is provided from the corresponding position S1 of the auxiliary intake port 102b to the exhaust port 1b.
The recesses 126 are formed with a predetermined depth toward the corresponding positions E1 and E2 of the 03a and 103b, and both sides of the recess 126 are linearly expanded from the corresponding position S1 toward the corresponding positions E1 and E2. The position P in the figure is the corresponding position of the main intake port 102a.

Therefore, in the non-uniform flow means 122 of this embodiment, the air flowing into the combustion chamber 123 from the auxiliary intake port 102b is not
It is guided by 26 and flows toward the center between the exhaust ports 103a and 103b.

The shape of the recess 126 may be a curved surface that bulges outward on both sides, as shown in FIG.
As shown in FIG. 11, both sides of the recess 126 may be formed parallel to each other. Further, the recess 126 is not limited to these shapes, and the inflow air from the auxiliary intake port 102b extends over the entire area of the combustion chamber 123 as the recess 126. The shape may be any that can be efficiently supplied.

By the way, in each of the above-mentioned embodiments, the one in which the two ports 103a and 103b are provided as the exhaust ports is disclosed, but the present invention is not limited to this, and the exhaust ports may be one or three or more, Regardless of the number of exhaust ports, as the non-uniform flow means 122, the air flowing in from the auxiliary intake port 102b may be supplied by directing the air toward substantially the center of all the exhaust ports.

The direction in which the inflowing air into the auxiliary intake port 102b by the non-uniform flow means 122 is not limited to the substantially central portion of the exhaust port, but the same function can be obtained by directing the central portion of the combustion chamber 123.

Further, in each of the above-described embodiments, the intake device 100 in which both the means for directing the auxiliary intake port 102b in the vertical direction with respect to the cylinder axis C and the deflecting means 122 are respectively provided are disclosed, but the present invention is not limited to this. It is needless to say that the effect can be significantly improved by using either one of the means as compared with the conventional intake device.

<< Effects of the Invention >> As described above, in the supercharged engine of the present invention, since the auxiliary intake port for supplying only intake air is formed in a direction substantially perpendicular to the cylinder axis, When the intake control valve is opened, the inflow direction of intake air supplied from the auxiliary intake port into the combustion chamber is substantially perpendicular to the moving direction of the piston.

Therefore, the inflow intake air from the auxiliary intake port is hardly affected by the rising pressure of the piston in the latter half of the exhaust stroke, and the combustion gas in the combustion chamber can be effectively scavenged with high energy at the time of inflow of the intake air. it can.

For this reason, the temperature in the combustion chamber can be lowered, whereby the knock resistance can be remarkably improved and a high compression ratio can be achieved. Also,
Combined with prevention of afterburn and the like, it has an excellent effect that a great improvement in combustion efficiency and an improvement in response can be achieved, and also a great increase in output can be achieved.

[Brief description of drawings]

FIG. 1 is a cross sectional view showing an embodiment of an engine with a supercharger according to the present invention, and FIG. 2 is a vertical cross sectional view of the embodiment shown in FIG.
FIG. 3 is an explanatory view showing the valve timing in the same embodiment of the present invention, FIG. 4 is a schematic plan view in the same embodiment of the present invention, and FIGS. 5, 6, and 7 are other views of the present invention. FIG. 8 is a schematic plan view corresponding to FIG. 4, FIG. 8 is a schematic vertical sectional view showing still another embodiment of the present invention, and FIG. 9 is a schematic plan view of the same embodiment. 10 and 11 are schematic plan views corresponding to FIG. 9 showing another embodiment of the present invention, and FIG. 12 is a schematic vertical sectional view showing a conventional intake device. 100 ... Intake device 101 ... Engine 102a ... Main intake port 102b ... Sub intake port 103a, 103b ... Exhaust port 104a, 104b ... Intake valve 105a, 105b ... Exhaust valve 110 ... Intake manifold 111, 112 ... Branch pipe 114,115 ...... Branch passage 120 ...... Shutter valve (intake control valve) 122 …… Differential flow means 123 …… Combustion chamber C …… Cylinder axis

Claims (1)

(57) [Claims] 1. At least one main intake port for supplying an air-fuel mixture and at least one auxiliary intake port for supplying only intake air are independently opened in one cylinder, respectively, and are upstream of the auxiliary intake port. An intake control valve for supplying and blocking intake air to the auxiliary intake port is provided, and the intake control valve is opened in a predetermined high load operation state to overlap the opening timing of the exhaust port from the auxiliary intake port into the combustion chamber. And supply the auxiliary intake port to the combustion chamber,
An engine with a supercharger characterized in that it is oriented almost perpendicularly to the cylinder axis.