JP3272528B2 - Valve train for engine with subchamber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-off valve which has a sub-chamber opening to a combustion chamber, and is provided at the opening of the sub-chamber to open a valve during a compression stroke and introduce a compressed air-fuel mixture into the sub-chamber. The present invention relates to a valve train for an engine with a sub-chamber provided with:

[0002]

2. Description of the Related Art In recent years, it has been proposed to form a sub-chamber opening into a combustion chamber in an engine body and to introduce a compressed air-fuel mixture into the sub-chamber.
No. 1 (F02D 15/04) or JP-A-5-33
In Japanese Patent No. 685 (F02D 15/04), the compressed air-fuel mixture introduced into the sub chamber in the compression stroke of the previous cycle is discharged into the combustion chamber in the compression stroke of the next cycle.
Further, in Japanese Patent Application No. 4-22009, the variable compression ratio engine is configured by opening the sub chamber to increase the substantial volume of the combustion chamber.

That is, in an engine having such a sub-chamber, the opening to the combustion chamber is opened during a predetermined period of the compression stroke by an on-off valve linked to a valve operating mechanism. In the engine, the compressed air-fuel mixture taken into the sub-chamber is cooled and discharged by the compression stroke of the next cycle, so that the temperature of the air-fuel mixture to be compressed can be lowered. In particular, by applying this to a lean-burn engine with a supercharger in which the knocking region is a high-speed high-load region, a great effect can be exhibited. On the other hand, in the latter engine with a sub-chamber, when the sub-chamber is opened, the substantial compression ratio is reduced to suppress the occurrence of knocking.

[0004]

However, in such a conventional engine with a sub-chamber, the opening / closing valve of the sub-chamber which is opened / closed in conjunction with the valve operating mechanism is the same as the ordinary intake valve and exhaust valve. The spring is biased in the valve closing direction. However, high-pressure compressed air-fuel mixture introduced in the compression stroke is sealed in the sub-chamber, and the sealed high pressure acts in the direction of opening the on-off valve in the exhaust stroke and the suction stroke in which the cylinder internal pressure is reduced. Therefore, the valve closing force of the on-off valve is reduced. For this reason, in order to improve the sealing performance when the on-off valve is closed, it is necessary to increase the spring urging force. However, when the urging force of the spring is increased in this way, the sub chamber is opened. Therefore, it is necessary to apply a large force to the on-off valve against a large urging force, and there is a problem that friction loss increases.

In view of the above-mentioned problems, the present invention is to maintain a large closing force when the on-off valve of the sub-chamber is in a closed state and reduce the force when the on-off valve is opened. It is an object of the present invention to provide a valve operating device for an engine with a sub-chamber that can perform the following.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a subchamber in which an opening opening to a combustion chamber is opened in a compression stroke through an on-off valve, and the subchamber is provided with a compression chamber. In an engine with a sub-chamber that introduces part of the air-fuel mixture, the on- off valve closes as the internal pressure increases according to the cylinder internal pressure.
In order to increase the valve urging force, a valve closing force variable mechanism for varying the valve closing urging force of the opening / closing valve is provided .
Is slidably fitted in the sub chamber with one end facing the sub chamber.
The other end is provided with a pressure-receiving surface of a spring for closing the on-off valve.
With the biasing force of the spring according to the cylinder internal pressure.
A configuration is provided with an inner piston that displaces in opposition .
That is, the closing force of the on-off valve is made variable in accordance with the amount of movement of the inner piston .

Further, it is desirable that the sub-chamber has a variable volume structure in accordance with the cylinder internal pressure.

[0008] Furthermore, the valve closing force control mechanism, between a first spring mounted under compression between the spring seat provided on the stem of the engine body the on-off valve, and the inner piston and the spring seat And a second spring arranged in parallel with the first spring.

The sub-chamber has a closed structure, and the compressed air-fuel mixture introduced into the sub-chamber in the high-pressure part of the compression cycle of the previous cycle is discharged into the combustion chamber in the low-pressure part of the compression cycle of the next cycle. I do.

Further, the sub-chamber is communicated with a pressure release passage communicating with the outside of the cylinder, and the compressed air-fuel mixture introduced into the sub-chamber is discharged through the pressure release passage in a stroke other than the compression stroke, thereby enabling variable compression. A ratio engine can be configured.

Furthermore, it is desirable that the pressure release passage communicates with an intake passage.

Further, it is desirable that the above-mentioned components be applied to an engine having a supercharger and having an air-fuel ratio that is operated lean in the entire operation range.

[0013]

With the above arrangement, in the valve gear of the engine with the sub-chamber according to the present invention, the closing force of the on-off valve for opening and closing the opening of the sub-chamber by the variable valve closing force mechanism is adjusted according to the cylinder internal pressure. When the pressure sealed in the sub-chamber is high, the valve closing biasing force is increased to prevent the sealed compressed air-fuel mixture from leaking from the opening. Can be improved.

Here, the variable valve closing force mechanism has a variable valve closing force.
The change mechanism is slidable in the sub-chamber with one end facing the sub-chamber
The other end receives a spring for closing the on-off valve at the other end.
With a pressure surface, the spring is attached according to the cylinder internal pressure.
A configuration with an inner piston that displaces against the power
Then, by varying the valve closing urging force of the on-off valve in accordance with the amount of displacement of the inner piston to be displaced, the higher the internal pressure of the cylinder and the higher the pressure of the compressed air-fuel mixture introduced into the sub chamber, the more the inner piston The movement amount increases, and the valve closing urging force of the on-off valve can be increased accordingly.

Further, by making the sub-chamber a variable volume structure in accordance with the cylinder internal pressure, when the cylinder internal pressure is high, the volume of the sub-chamber is increased to lower the compression ratio and effectively suppress knocking. be able to.

[0016] Furthermore, the valve closing force control mechanism, between a first spring mounted under compression between the spring seat provided on the stem of the engine body the on-off valve, and the inner piston and the spring seat And a second spring arranged in parallel with the first spring, so that the first spring is displaced in accordance with the internal pressure of the cylinder.
The amount of compression of the second spring changes in accordance with the amount of movement of the inner piston, and the urging force of the second spring
The urging force of the spring acts on the spring seat,
This is the urging force of the on-off valve. Therefore, as the cylinder internal pressure increases, the urging force of the second spring increases, and the valve closing urging force can be increased. Also, when opening the on-off valve, if the on-off valve is opened even a little and the pressure sealed in the sub chamber is discharged, the inner piston moves in the direction of decreasing the volume and the second Since the urging force of the spring is reduced and, consequently, the urging force of closing the on-off valve is reduced, the opening force of the on-off valve can be reduced.

Further, the sub-chamber has a closed structure, and the compressed air-fuel mixture introduced into the sub-chamber at the high pressure portion of the compression cycle of the previous cycle is discharged into the combustion chamber at the low pressure portion of the compression stroke of the next cycle. By doing so, the compressed air-fuel mixture discharged in the next cycle is cooled in the sub-chamber, so that the temperature in the combustion chamber is reduced and knocking can be suppressed.

Further, the sub-chamber is communicated with a pressure release passage communicating with the outside of the cylinder, and the compressed air-fuel mixture introduced into the sub-chamber is discharged through the pressure release passage in a stroke other than the compression stroke. Since the pressure of the compressed air-fuel mixture introduced into the fuel cell can be reduced, knocking can be suppressed.

Further, by connecting the pressure release passage to the intake passage, the air-fuel mixture can be supplied to the combustion chamber again for use, and the gas can be prevented from leaking outward.

Further, by applying each of the above-described components to an engine having a supercharger and operating lean in the entire operation range of the air-fuel ratio, it is possible to effectively suppress knocking in a high-speed range of the engine. it can.

[0021]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. 1 to 8 show an embodiment of a valve train of an engine with a sub-chamber according to the present invention. FIG. 1 is a schematic configuration diagram of the engine, FIG. 6 is an enlarged sectional view of a main part showing the operation state of the sub-chamber on-off valve in order, FIG. 7 is an explanatory diagram showing the spring characteristics of the first and second springs, and FIG. FIG. 7 is an explanatory diagram showing a relationship between the biasing force of the second spring and the second spring.

That is, as shown in FIG. 1, the engine 10 with a sub-chamber according to the present embodiment is provided with sub-chambers 14 which open into the combustion chamber 12a of the cylinder 12, respectively. Subchamber 14 is shown in FIG.
As shown in FIG.
An opening 14 a is formed together with the exhaust port 18. The opening 14a of the sub-chamber 14 is opened and closed by an on-off valve 24 interlocked with a valve operating mechanism in the same manner as the intake port 16 and the exhaust port 18 are opened and closed by an intake valve 20 and an exhaust valve 22. ing.

An intake passage 26 leading to the intake port 16
Of the fuel injection valve 2 in the branches 26a, 26a,.
, And a throttle valve 30, an intercooler 3,
2, a compressor 34a of the turbocharger 34 and an air flow meter 36 are provided. On the other hand, a turbine 34b of the turbocharger 34 is provided in an exhaust passage 38 communicating with the exhaust port 18, and the wastegate valve 4 bypasses the turbine 34b.
0 is provided.

Further, a supercharging pressure sensor 42 is provided in the intake passage 26, a rotation speed sensor 46 is provided near the outer periphery of the flywheel 44, and a throttle opening sensor 48 is provided in the throttle valve 30. The detection signals of the supercharging pressure sensor 42, the rotation speed sensor 46, the throttle opening sensor 48, and the air flow meter 36 are input to the microcomputer 50. The microcomputer 50 includes the sensors 42 and 4.
The fuel injection amount and the opening of the wastegate valve 40 are determined based on the detection signals 6 and 48, and these control signals are output to the fuel injection valve 28 and the wastegate valve 38.

In the engine 10 with the sub-chamber having such a configuration, when the pressure in the cylinder is changed from the compression stroke to the explosion stroke and the exhaust stroke, the opening / closing valve 24 of the sub-chamber 14 is opened for a predetermined period of the compression stroke. You. Thus, the on-off valve 24
Is opened, the compressed air-fuel mixture introduced into the sub-chamber 14 in the previous cycle is discharged into the combustion chamber 12a at a stage where the pressure inside the cylinder is low, and the compressed air-fuel mixture due to the rise in the pressure inside the cylinder is reduced. Is introduced again into the sub-chamber 14 and is confined.

The on-off valve 24 is shown in FIGS.
As shown in FIG. 5, a valve body 24a for opening and closing the opening 14a of the sub chamber 14 and a stem 24b projecting from the valve body 24a through the sub chamber 14 are provided. A cam seat 52 to be contacted by a cam of a valve operating mechanism (not shown) is disposed. The cam seat 52 has a bottom 5 at the upper end.
The cam is in contact with the upper surface of the bottom portion 52a, and the upper end of the stem 24b is in contact with the center of the lower surface of the bottom portion 52a.

At the upper end of the stem 24b, a disc-shaped spring seat 54 is fixedly fitted (movably relatively) into the cylindrical cam seat 52. The spring seat 54 and the cylinder head are fixed. An outer spring 56 as a first spring is contracted between the opening and closing portion 14a and the opening and closing valve 14a.

An inner piston 58 is slidably and closely fitted to the upper end (upper side in the figure) of the sub-chamber 14. The inner piston 58 together with the end side facing the auxiliary chamber 14 facing the opposite other end the cylinder head 10a outwardly of (upward in the drawing), the stem 24b is slidably in the center of the inner piston 58 It is inserted closely. The other end facing the outside of the inner piston 58 is for closing the on-off valve 24.
An inner spring 60 as a second spring concentrically disposed inside the outer spring 56 is formed between the pressure receiving surface and the spring seat 54. It will be curtailed.

The spring characteristics of the outer spring 56 and the inner spring 60 are set as shown in FIG. 7, and the spring characteristics of the outer spring 56 are shown in the upper part and the spring characteristics of the inner spring 60 are shown in the lower part. The outer spring 56 is set in the closed state of the on-off valve 24 shown in FIG. 5, and the spring constant at this time is WS2.
Further, the lift state is established when the on-off valve 24 shown in FIGS. 3 and 4 is open, and the spring constant at this time is WL2. On the other hand, the spring constant of the inner spring 60 becomes WL1 in the lift state shown in FIG. 3, and the spring constant becomes WP1 in the inner piston top state shown in FIGS.

With the above configuration, in the engine 10 with a sub-chamber, the compressed air-fuel mixture introduced into the sub-chamber 14 in the previous cycle is cooled to some extent by the cooling water by the compression stroke of the next cycle. . When the on-off valve 24 is opened in the compression stroke of the next cycle, the compressed air-fuel mixture sealed in the sub-chamber 14 is discharged into the combustion chamber 12a at the initial stage of the valve opening. Since the air-fuel mixture in the chamber 14 is cooled, the temperature of the air-fuel mixture that is being compressed and heated to a high temperature in the combustion chamber 12a can be reduced. Therefore, finally, the temperature in the combustion chamber 12a at the time of ignition can be lowered, and the occurrence of knocking can be effectively suppressed.

The open / close valve 24 of the sub-chamber 14 is opened in the compression stroke as shown in FIG. 3 to introduce the compressed air-fuel mixture G and closed at the top dead center before ignition as shown in FIG. The compressed air-fuel mixture G is sealed in the sub-chamber 14 and opened again in the compression stroke of the next cycle as shown in FIG. At this time, an inner piston 58 is provided in the sub-chamber 14, and an outer piston 56 and an inner spring 60 contracted between the spring seat 54 of the on-off valve 24 and the cylinder header 10 a and the inner piston 58, respectively. A valve closing force is applied.

At this time, when the on-off valve 24 is open as shown in FIG.
Is biased in the valve closing direction with a combined biasing force WL1 + WL2 of
In this state, the compressed air-fuel mixture G is introduced. Then, the auxiliary chamber 14 pressure by compressing the air-fuel mixture G is introduced is increased, the inner piston 58 as shown in FIG. 4 cylinder
-Against the urging force of both springs 56 and 60 according to the internal pressure
When the inner spring 60 is displaced by being pushed up, the biasing force of the inner spring 60 increases, and the resultant biasing force at this time is WP1
+ WL2.

Next, in the valve-closing state of FIG. 5, the biasing force of the inner spring 60 whose biasing force has been increased is added to the set biasing force of the outer spring 56, so that the combined biasing force W
The valve closed state is maintained with a large load of P1 + WS2. Therefore, even when the high-pressure compressed air-fuel mixture G is sealed in the sub-chamber 14, the valve closing force is increased to maintain the sealing performance, and the sub-chamber 1 is located in the exhaust stroke and the intake stroke where the cylinder internal pressure is reduced.
When the pressure difference with the inside of the subchamber 4 increases,
Leakage of the compressed air-fuel mixture G sealed in the air-fuel mixture can be prevented.

Then, in the compression stroke of the next cycle, the on-off valve 58 is opened again as shown in FIG.
The valve 8 is opened by pushing down the cam seat 52 in a state where the valve closing biasing force is large as shown in FIG.
Is opened. At this time, when the valve body 24a starts to open, the pressure in the sub-chamber 14 is discharged into the cylinder and decreases, and the inner piston 58 moves in the direction of decreasing the inner volume of the sub-chamber 14 by the urging force of the inner spring 60. Push down,
Accordingly, the valve closing urging force of the inner spring 60 is reduced from WP1 + WS2 to WL1 + WL2, as shown in FIG. Therefore, the valve opening force of the on-off valve 24 is rapidly reduced by the start of valve opening, and the force required for valve lift is also reduced, so that friction loss can be significantly reduced.

The engine 10 with a sub-chamber in this embodiment is a turbocharger 34 (may be a supercharger).
In particular, the effect is exhibited by applying the present invention to a lean burn engine in which the air-fuel ratio is lean in the entire operation range, and knocking in a high engine speed region can be effectively suppressed. FIG. 19 to FIG. 19 show another embodiment, in which the same components as those in the above embodiment are denoted by the same reference numerals, and the description thereof will be omitted. 9 to FIG.
3 is an explanatory view showing the operation of the on-off valve and the on-off valve in order according to each stroke, and FIGS. 14 to 17 are enlarged sectional views of a main part showing the operation states of the on-off valve and the on-off valve in order, FIGS.
FIG. 9 is an explanatory view showing an operation state of the inner piston in a high load state and a light load state.

In this embodiment, the sub chamber 14 is connected to the pressure release passage 1.
A sub-opening / closing valve 102 that opens and closes the pressure release passage 100 is provided while communicating with an intake passage (not shown) through the internal combustion engine 00, and the pressure in the sub-chamber 14 is transmitted to the intake passage by opening the sub-opening / closing valve 102. It is designed to release. The on-off valve 24 of the sub-chamber 14 is opened in the compression stroke (see FIG. 9) and closed at the top dead center where the compression stroke ends (see FIG. 10), as in the previous embodiment. 11 to FIG.
In each of the explosion, exhaust and intake strokes shown in FIG. 3, the closed state of the on-off valve 24 is maintained. On the other hand, the auxiliary on-off valve 10
2 is closed during the compression stroke shown in FIGS. 9 and 10, and is opened during each of the explosion, exhaust, and intake strokes shown in FIGS.

In this embodiment, as in the previous embodiment, an inner piston 58 and an inner spring 60 are provided in the sub-chamber 14.
In the open state of No. 4, the combined biasing force of the outer spring 56 and the inner spring 60 is WL1 + WL2, and FIG.
When the inner piston 58 is pushed up, the combined biasing force is WP1 + WL2. In the valve closing state shown in FIG. 16, the combined biasing force is a large load of WP1 + WS2, and the sealing performance can be improved with a large valve closing force. Further, since the pressure in the sub-chamber 14 is released by opening the sub-opening / closing valve 102, the combined urging force is changed from WP1 + WS2 to WL1 + W.
Reduced to L2. Therefore, the valve opening force of the on-off valve 24 is reduced, and the force required for valve lift is also reduced, so that friction loss can be greatly reduced.

In this embodiment, since the volume of the sub-chamber 14 can be made variable in accordance with the pressure of the compressed air-fuel mixture introduced by the inner piston 58, the inner piston 58 in a high load state shown in FIG. , The stroke amount L of the sub-chamber 14 can be increased, and the volume in the sub-chamber 14 can be increased. Therefore, by increasing the amount of the compressed air-fuel mixture introduced into the sub-chamber 14, the effective compression ratio in the cylinder is reduced, and the knocking resistance can be greatly improved.

On the other hand, in the light load state shown in FIG. 19, the stroke amount L of the inner piston 58 becomes small,
The volume change in the interior is reduced. Therefore, since the amount of the compressed air-fuel mixture introduced into the sub-chamber 14 is reduced, the effective compression ratio in the cylinder does not change so much, and the pumping loss can be reduced without lowering the output.

[0040]

As described above, in the valve operating system for an engine with a sub-chamber according to the first aspect of the present invention, the on-off valve for opening and closing the opening of the sub-chamber by the variable valve closing force mechanism. The biasing force is made variable according to the cylinder internal pressure, so when the pressure sealed in the sub-chamber is high, the valve closing biasing force is increased to prevent the sealed compressed mixture from leaking from the opening. Therefore, the sealing property of the on-off valve can be improved, and the compressed air-fuel mixture sealed in the sub chamber can be prevented from leaking.

Here, the variable valve closing force mechanism has one end in the sub chamber.
To the sub-chamber slidably facing
Has a pressure-receiving surface of a spring for closing the valve, inside the cylinder
The spring is displaced against the urging force of the spring according to the pressure.
The inner piston that is displaced
Since the closing force of the on-off valve is made variable in accordance with the amount of movement of the ston, the amount of movement of the inner piston is increased as the internal pressure of the cylinder is higher and the pressure of the compressed air-fuel mixture introduced into the sub-chamber is higher. The valve closing urging force of the on-off valve can be increased accordingly.

Further, in the second aspect of the present invention, since the sub-chamber has a volume variable structure according to the cylinder internal pressure, when the cylinder internal pressure is high, the volume of the sub-chamber is increased and the compression ratio is reduced. Therefore, knocking can be effectively suppressed.

Further, in claim 3 of the present invention,
A first spring that contracts the valve closing force variable mechanism between an engine body and a spring seat provided on a stem of the on-off valve; And a second spring that is contracted between the inner piston and the spring seat and arranged in parallel with the first spring. The amount of compression of the second spring changes in accordance with the amount of movement of the spring, and the urging force of the second spring and the urging force of the first spring act on the spring seat to become the urging force of the on-off valve. Therefore, as the cylinder internal pressure increases, the second
The urging force of the spring is increased, and the urging force of the valve closing is increased, so that the sealing performance can be improved. When the on-off valve is opened, the pressure sealed in the sub-chamber is discharged by the start of opening of the on-off valve, and the inner piston moves in a direction to reduce the volume, and the urging force of the second spring is increased. Therefore, the closing force of the on-off valve is reduced to reduce the force at the time of opening the on-off valve, and the friction loss can be greatly reduced.

According to a fourth aspect of the present invention, the sub-chamber has a closed structure, and the compressed air-fuel mixture introduced into the sub-chamber at the high pressure portion of the compression stroke of the previous cycle is used for the compression stroke of the next cycle. With the configuration in which the compressed air-fuel mixture discharged in the next cycle is cooled in the sub-chamber, the temperature in the combustion chamber can be reduced to suppress knocking by having a configuration in which the compressed air-fuel mixture is discharged into the combustion chamber in the low pressure portion.

Further, according to a fifth aspect of the present invention, the sub-chamber is communicated with a pressure release passage communicating with the outside of the cylinder, and the compressed air-fuel mixture introduced into the sub-chamber is subjected to the pressure release in a stroke other than the compression stroke. Since the exhaust gas is discharged through the passage, the pressure of the compressed air-fuel mixture introduced into the sub-chamber can be reduced, so that knocking can be suppressed.

Further, in claim 6 of the present invention,
By connecting the pressure release passage to the intake passage, the air-fuel mixture can be supplied to the combustion chamber again for use, and the gas can be prevented from leaking outward.

According to a seventh aspect of the present invention, each of the above-described components is provided with a supercharger and is applied to an engine in which the air-fuel ratio is in a lean operation in the entire operation range. Various kinds of excellent effects that knocking can be effectively suppressed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a plan view of an embodiment of an engine with a sub-chamber according to the present invention.

FIG. 2 is an enlarged schematic view of a main part of a combustion chamber portion showing an embodiment of an engine with a sub-chamber according to the present invention.

FIG. 3 is an enlarged sectional view of a main part showing an open state of an on-off valve of an engine with a sub-chamber showing an embodiment of the present invention, showing a state immediately after the start of introduction of compressed air into the sub-chamber.

FIG. 4 is an enlarged sectional view of a main part showing an open state of an on-off valve of an engine with a sub-chamber showing an embodiment of the present invention, showing a state where a compressed air-fuel mixture is being introduced into the sub-chamber.

FIG. 5 is an enlarged sectional view of a main part showing a closed state of an on-off valve of an engine with a sub-chamber showing an embodiment of the present invention.

FIG. 6 is an enlarged sectional view of a main part showing a start point of opening of an on-off valve of an engine with a sub-chamber according to an embodiment of the present invention.

FIG. 7 is an explanatory diagram showing spring characteristics of first and second springs of the on-off valve of the engine with a sub-chamber showing the embodiment of the present invention.

FIG. 8 is an explanatory diagram illustrating a relationship between a valve lift of an on-off valve of an engine with a sub-chamber and an urging force of first and second springs according to the embodiment of the present invention.

FIG. 9 is an explanatory view showing a compression stroke of an engine with a sub-chamber showing another embodiment of the present invention.

FIG. 10 is an explanatory diagram showing a top dead center state of a compression stroke of an engine with a sub-chamber showing another embodiment of the present invention.

FIG. 11 is an explanatory view showing an explosion stroke of an engine with a sub-chamber showing another embodiment of the present invention.

FIG. 12 is an explanatory view showing an exhaust stroke of an engine with a sub-chamber showing another embodiment of the present invention.

FIG. 13 is an explanatory diagram showing an intake stroke of an engine with a sub-chamber showing another embodiment of the present invention.

FIG. 14 is an enlarged sectional view of an essential part showing an initial state of opening of an on-off valve of an engine with a sub-chamber showing another embodiment of the present invention.

FIG. 15 is an essential part enlarged cross-sectional view showing a state in which a compressed air-fuel mixture is introduced into a sub-chamber when an on-off valve of an engine with a sub-chamber is opened according to another embodiment of the present invention.

FIG. 16 is an enlarged sectional view of a main part showing a closed state of an on-off valve of an engine with a sub-chamber showing another embodiment of the present invention.

FIG. 17 is an enlarged cross-sectional view of a main part showing a start point of opening of a sub-opening / closing valve of an engine with a sub-chamber showing another embodiment of the present invention.

FIG. 18 is an explanatory view showing an operation state of an inner piston in a high load state of an engine with a sub-chamber showing another embodiment of the present invention.

FIG. 19 is an explanatory view showing an operation state of an inner piston in a light load state of an engine with a sub-chamber showing another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 10 engine with sub-chamber 12 cylinder 12a combustion chamber 14 sub-chamber 14a opening 24 on-off valve 24a valve body 24b stem 34 turbocharger 52 cam seat 54 spring seat 56 outer spring (first spring) 58 inner piston 60 inner spring (second spring) 100 Pressure release passage 102 Sub opening / closing valve

Continuation of the front page (56) References JP-A-58-138220 (JP, A) JP-A-7-34874 (JP, A) JP-A-58-187518 (JP, A) JP-A-60-36722 (JP, A) JP-A-61-268829 (JP, A) JP-A-61-160225 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02B 21/00-23/10 F02D 13/02 F02D 15/04 F02B 19/06

Claims (7)

(57) [Claims] 1. An engine with a sub-chamber, wherein an opening opening to a combustion chamber is provided with a sub-chamber which is opened in a compression stroke via an on-off valve, and a part of the compressed air-fuel mixture is introduced into the sub-chamber. According to the internal pressure, the higher the internal pressure, the more the on-off valve closes.
In order to increase the valve urging force, a valve closing force variable mechanism for varying the valve closing urging force of the opening / closing valve is provided .
Is slidably fitted in the sub chamber with one end facing the sub chamber.
The other end is provided with a pressure-receiving surface of a spring for closing the on-off valve.
With the biasing force of the spring according to the cylinder internal pressure.
A valve train for an engine with a sub-chamber, comprising an inner piston displaced in opposition. 2. The sub-chamber is accommodated in accordance with the cylinder internal pressure.
The sub product according to claim 1, wherein the sub product has a variable structure.
Valve train for engine with compartment. 3. The variable valve closing force mechanism includes an engine body and
Between the spring seat provided on the stem of the on-off valve
A first spring to be contracted and the inner piston
The first spring
A structure including a ring and a second spring arranged in parallel
Valve train subchamber with engine according to claim 1, characterized in that the. 4. The sub-chamber has a sealed structure, and
Compression mixing introduced in the high-pressure part of the compression cycle of the previous cycle
Air into the combustion chamber in the low pressure part of the compression stroke of the next cycle.
Valve train subchamber with engine according to claim 1, characterized in that the output 3. 5. A pressure release for passing said sub-chamber out of a cylinder.
The compressed air-fuel mixture introduced into the sub-chamber communicates with the passage
To discharge through this pressure release passage
The valve train of an engine with a sub-chamber according to any one of claims 1 to 3 , further comprising a variable compression ratio engine . 6. The valve train of an engine with a sub-chamber according to claim 5 , wherein the pressure release passage communicates with an intake passage . 7. A supercharger is provided, and an air-fuel ratio is set for all operations.
The valve train of an engine with a sub-chamber according to any one of claims 1 to 6 , wherein the valve train is applied to an engine operated lean in a region .