JPH07189839A - Intake device of internal combustion engine - Google Patents

Abstract

PURPOSE:To provide an intake air variable system in which no rapid charge of its output takes place, low speed torque is increased, and no increase in its weight happens. CONSTITUTION:A counterflow prevention means 14 for preventing counterflow of air-fuel mixture from an engine to an intake port 8 and a control valve 12 are provided for increasing low speed torque while delaying closing angle of an intake valve. Promotion of turbulence at the time of the high speed torque, low speed torque and partial load can be thus mutually compatible, and also an intake variable system in which not rapid change of its output takes place, low speed torque is increased, and no increase in its weight happens.

Description

Detailed Description of the Invention

[0001]

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 an intake system for a gasoline engine for an automobile having a wide range of rotational speeds to be used.

[0002]

2. Description of the Related Art Conventionally, a lift characteristic of an intake valve and an exhaust valve is made variable according to operating conditions in order to parallelize acceleration of high-speed torque, low-speed torque, and turbulence at partial load with respect to an automobile gasoline engine. The following intake variable system is presented.

(1) Cams with different profiles are prepared and switched according to operating conditions.

(2) A control valve is provided in the intake port, and the disclosure is adjusted according to operating conditions.

(3) The intake valve and the exhaust valve are directly driven by an electromagnetic solenoid and a hydraulic piston.

[0006]

In the above (1), the cam is switched during one cycle. Since the switching is rapid, the output of the engine suddenly changes and the drivability deteriorates.
In (2), the closing angle of the intake valve cannot be increased and the low speed torque cannot be increased. In (3), the solenoid and piston become large in size to resist the force of the spring of the intake valve, and the weight increases, which increases fuel consumption.

An object of the present invention is to provide an intake variable system in which output does not suddenly change, low speed torque increases, and weight does not increase.

[0008]

[Means for Solving the Problems] The above means (2) is (1), in that the weight does not increase and the output does not suddenly change.
Although it is superior to (3), since there is no action to increase the closing angle of the intake valve, the low speed torque cannot be increased.
Therefore, in order to increase the low-speed torque with the intake valve closing angle kept low, a means for preventing backflow of the air-fuel mixture from the engine is added.

In addition, in the above (1), a means for avoiding a sudden change in the operating state at the time of switching the cam may be provided.

[0010]

Since the control valve is provided in the suction port upstream of the intake valve of the engine and the means for preventing the backflow of the air-fuel mixture is added, the following effects are obtained.

(A) At high speed: The control valve is opened to reduce fluid resistance and secure high speed torque.

(B) At low speed: A means for preventing the backflow of the air-fuel mixture, for example, a reed valve, prevents the backflow of the air-fuel mixture and secures a low-speed torque.

(C) Partial load: The opening of the control valve is made small, the speed of the air-fuel mixture passing through the intake valve is increased, and turbulence is promoted.

Further, in the above (1), by providing a means for avoiding a sudden change in the operating state at the time of switching the cam, the combustion such as the fuel injection timing, the injection amount, the air amount, the ignition timing, etc. can be performed simultaneously with the switching of the cam. Control the variables involved in. This allows
By switching the cam, for example, a phenomenon in which the eddy current is sharply reduced, the turbulence is reduced, the combustion is delayed, and the torque is reduced can be avoided by advancing the ignition timing at the same time as the switching of the cam. Conventionally, the ignition timing is controlled by the intake pipe pressure and the rotation speed. The change in the intake pipe pressure is delayed with respect to the cam switching, so there was torque fluctuation.
By correcting the above variables with the cam switching information, the torque fluctuation is reduced.

[0015]

FIG. 1 shows a first embodiment of the present invention. The intake valves 2 and 3 are arranged in the cylinder 1. The exhaust valve is omitted. The valves 2 and 3 are rocker arms 4 and
Rocker arms 4 and 5 driven respectively by
Are driven by cams 6, 7. At this time, the lift of the valves 2 and 3 is determined by the shapes of the cams 6 and 7.
An intake port 8 is arranged upstream of the intake valves 2 and 3,
The fuel injection valve 9 is attached at a suitable position. The injection valve 9 has two injection holes, and the respective jets 10, 1
1 is supplied to the cylinder 1 from the intake valves 2 and 3.
A control valve 12 is provided in the intake port 8 and is driven by a stepping motor 13.

Further, the intake port 8 is provided with a backflow prevention means 14, here a reed valve. The lead 15 in the passage 16 is an elastic thin plate.

The operation of the variable intake system configured as shown in FIG. 1 will be described below.

At high speed: The motor 13 fully opens the control valve 12 to prevent an increase in intake resistance. Lead 15
However, it is prevented from being deflected by the air flow and increasing the intake resistance. At the time of reverse flow, the lead 15 is returned, the passage 16 is closed, and the reverse flow of the air-fuel mixture is prevented. The shapes of cams 6 and 7 are
It is a high-speed specification, which ensures high-speed torque. Low speed: The control valve 12 remains open. Since the shapes of the cam 6 and the cam 7 are high-speed specifications, backflow is easy at low speed. However, the lead 15 quickly returns, closing the passage 12 and preventing backflow. This ensures low speed torque. In order to prevent backflow, it is desirable that the backflow prevention means 14 be as close as possible to the intake valves 2 and 3. Therefore, the backflow prevention means 14 can be attached downstream of the injection valve 9 and the control valve 12. At this time, the jet flows 10 and 11 adhere to the lead 16 and the inflow into the cylinder 1 is likely to be delayed. In order to prevent this, the fuel of the injection valve 9 is injected in the intake stroke in which the reed 16 is open.

At partial load: The motor 13 closes the control valve 12. The velocity of the air in the intake valve 2 becomes higher than that in the intake valve 3, and a swirl, that is, a swirl flow is generated in the cylinder 1 to promote the turbulence of the air-fuel mixture. The backflow prevention means 14 prevents the backflow of the residual gas and stabilizes the combustion. When the rotation speed increases, the motor 1
3 gradually opens the control valve 12 to prevent excessive vortex flow. FIG. 2 shows a second embodiment of the present invention. The backflow prevention means 14 is composed of a lead 15 and a passage 16, and a lead 17 is arranged on the intake valve 3 side. A stopper 18 for preventing the lead 17 from bending is added. Here, the deflection of the lead 17 can be suppressed by the stopper 18 only during partial load, the velocity of the air on the intake valve 3 side can be reduced, and a swirl flow can be formed in the cylinder 1. Thereby, the control valve 12 can be omitted. At low speeds and high speeds, the electromagnetic solenoid 19 pulls the stopper 18 to allow the lead 17 to bend and suppress an increase in fluid resistance. That is, the intake passage partial throttle means and the backflow prevention means are combined.

FIG. 3 shows a third embodiment of the present invention. Control valves 20 and 21 are arranged in the intake port 8 and are driven by motors 22 and 23, respectively. At high speed,
The control valves 20, 21 are opened to maintain high speed torque. During partial load, control valve 21 is closed and control valve 20 remains open to reduce the air velocity through intake valve 3 and promote turbulence in cylinder 1. At low speeds, the valves 20 and 21 open and close in synchronization with the intake stroke to prevent backflow. At this time, the valves 20 and 21 also serve as the intake passage partial throttle means and the backflow prevention means.

FIG. 4 shows a fourth embodiment of the present invention. Leads 25 and 26 are attached to the control valve 24, and the control valve 24 is driven by a motor 27. Motor 27 at high speed
As a result, the control valve 24 is fully opened, an increase in fluid resistance is suppressed, and high-speed torque is secured. At low speeds, the control valve 24 closes as shown. Air is lead 25,2
6 and is prevented from flowing back by the leads 25 and 26. At the time of partial load, the control valve 24 is slightly opened, the velocity of the air passing through the intake valve 2 is increased, and the turbulence in the cylinder 1 is promoted.

FIG. 5 shows a fifth embodiment of the present invention. An intake port 30 is arranged upstream of the intake valve 2, and an intake port 31 is arranged upstream of the intake valve 3. A control valve 32 is arranged in the intake port 31 and is driven by a motor 33.
At high speed, the control valve is opened by the motor 33,
Intake resistance is reduced to secure high-speed torque. At the time of partial load, the control valve 32 is closed, the air velocity of the intake valve 3 is reduced, the swirl in the cylinder 1 is increased, and turbulence is promoted. At low speed, the backflow of the intake valve 3 is suppressed by closing the control valve 32, and the backflow of the intake valve 3 is suppressed by the bending action of the reed 35 of the backflow prevention means 34.

FIG. 6 shows a sixth embodiment of the present invention. A control valve 32 is arranged in the intake port 32, the cam 6 has a low speed specification, and the cam 7 has a high speed specification. Control valve 3 at high speed
2 is fully opened, and the amount of air filled in the cylinder 1 is secured, so that high speed torque is secured. At low speed, the control valve 32 is closed, and air is supplied to the intake valve 2 of low speed specification.
Only supplied from. Since the closing angle of the low speed specification intake valve 2 is advanced, no backflow occurs. Therefore,
Low speed torque is secured. At partial load, control valve 32
Is closed, the air velocity passing through the intake valve 3 is reduced, and a vortex is formed. However, as it is, since the vortex flow is small, the control valve 38 is provided in the intake port 30,
It closes at partial load.

FIG. 7 shows a seventh embodiment of the present invention. Cam 6
Is a low speed specification, the cam 39 is a high speed specification, and the cam 40 is a rest specification. With the low speed specification, the closing angle of the intake valve is fast and the lift is small. With the high-speed specifications, the closing angle of the intake valve is slow and the valve lift is large. In the rest mode, the valve is almost closed and opens slightly to prevent fuel from accumulating above the intake valve. Cam 6
Rocker arm 4 with cam 39 rocker arm 41 with
However, the rocker arm 5 is driven by the cam 40. At high speed, the intake valve 2 is driven by the cam 6 and the cam 3
The intake valve 3 is operated by 9. The movement of the cam 39 is first transmitted to the rocker arm 41. At this time,
Since the pin 42 is connected to the rocker arm 5,
The rocker arm 5 also moves simultaneously with the rocker arm 41, and the valve 3 is moved. At this time, since the diameter of the cam 39 is larger than that of the cam 40, the cam 40 does not contact the rocker arm 5.

At low speed, the electromagnetic solenoid 43
The pin 42 is separated from the rocker arm 5, and the cam 39
Is not transmitted to the rocker arm 5, and the rocker arm 5 is driven by the cam 40. At this time, since the cam 40 is of a rest specification, the movement of the valve 3 is almost stopped. Air is intake valve 2
Is supplied only at this time, and at this time, since the intake valve 2 has a low speed specification, low speed torque is secured. During partial load, the control valve 44 is closed to promote turbulence in the cylinder 1. That is, the object can be achieved by combining a mechanism for switching the lift characteristics of the valve and a valve for controlling the air flow.

FIG. 8 shows an eighth embodiment of the present invention. The intake valve 3 is driven by either the cam 39 or the cam 40 as in the case of FIG. 7. Instead of providing the control valve 44 of FIG. 7, the lift of the valve 2 is reduced here under partial load. The cam 44 has a low speed specification, and moves the rocker arm 44 via the rocker arm 45 and the pin 46 to transmit the movement to the intake valve 2. At the time of partial load, the cam 6 of a partial load specification having a small lift moves the rocker arm 6 and the intake valve 2. At this time, the pin 46 is pulled by the electromagnetic solenoid 47 to disconnect the rocker arm 45 from the arm 4. During partial load, the lift of the intake valve 2 becomes small, the velocity of the air passing through the valve 2 increases, and turbulence is promoted.

In FIG. 8, a throttle valve 48 is provided upstream of the intake valves 2 and 3, driven by a motor 49, and a fuel injection valve 9 is provided upstream of the intake valve 9.
However, the spark plug 50 is attached to the cylinder 1.
A voltage is applied to the spark plug 50 by the ignition device 51. The control unit 52 controls the ignition timing of the ignition device 51, the valve opening time of the fuel injection valve 9, the injection timing, the position of the motor 49 (air amount), and the electromagnetic solenoid 4.
3, 47 are controlled. Variables related to combustion such as ignition timing, valve opening time, injection timing, and air amount are controlled by the control unit 52 based on the intake valve lift characteristic switching information (operation signals of the electromagnetic solenoids 43 and 47). Thereby, for example, the intake valve 2 at the time of partial load
When the operating state in which the lift is small is switched to the operating state of the low speed specification of the cam 44, it is possible to advance the ignition timing, compensate for the combustion delay, and avoid the torque fluctuation.

The lift characteristic of the intake valve can be changed by controlling the phase of the cam shaft in addition to switching the cam.

FIG. 9 shows a ninth embodiment of the present invention. A bypass passage 60 is provided in the intake port 8 so that a part of the air is
It is supplied at a high speed near the intake valve 2 and produces a strong vortex in the cylinder 1. At partial load, control valve 12 is closed and air is supplied through bypass passage 60. At low speed, the control valve 12 is opened by the motor 13 to reduce the fluid resistance and prevent the backflow.
Prevents backflow and secures low speed torque. At high speed, the cams 6 and 7 have high-speed specifications, so high-speed torque is secured.

FIG. 10 shows a tenth embodiment of the present invention, which shows the construction of an apparatus when combined with a mechanism for lean burn. 70 is provided in the intake port of each cylinder, and a passage 71 that bypasses the intake port is provided. During full load operation, the valve 70 is fully opened. During the partial load operation, the valve 70 is closed to allow the air to flow into the engine from the passage 71. With this air flow, a swirling flow of air is formed in the combustion chamber 1,
Improves combustion during lean operation. Even in this operating state, there is blowback from the engine, the intake efficiency is reduced, and lean combustion cannot be achieved. Therefore, it is necessary to prevent blowback even in an engine to which such a mechanism is added. A reed valve 72 is attached to the outlet of the passage 71 so that air is smoothly sucked into the engine on the intake side and the reed valve 72 is closed when the engine is blown back to prevent blowback.

[0031]

As described above, according to the present invention, it is possible to obtain the effect of accelerating the high-speed torque, the low-speed torque, and the turbulence under partial load of a gasoline engine for automobiles.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a third embodiment of the present invention.

FIG. 4 is a configuration diagram of a fourth embodiment of the present invention.

FIG. 5 is a configuration diagram of a fifth embodiment of the present invention.

FIG. 6 is a configuration diagram of a sixth embodiment of the present invention.

FIG. 7 is a configuration diagram of a seventh embodiment of the present invention.

FIG. 8 is a configuration diagram of an eighth embodiment of the present invention.

FIG. 9 is a configuration diagram of a ninth embodiment of the present invention.

FIG. 10 is a configuration diagram of a tenth embodiment of the present invention.

[Explanation of symbols]

1 ... Cylinder, 2, 3 ... Intake valve, 8 ... Intake port,
12 ... Control valve, 14 ... Backflow prevention means.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location F02D 43/00 301 Z F02M 35/10

Claims (5)

[Claims] 1. An intake system for an internal combustion engine, characterized in that a backflow prevention means and an intake passage partial throttle means are provided upstream of an intake valve. 2. An intake system for an internal combustion engine according to claim 1, wherein an intake bypass passage is provided in the intake port. 3. An intake valve operated by a high-speed cam,
An intake device for an internal combustion engine, comprising: an intake valve that operates with a low speed cam; and a valve that controls an air flow provided upstream of the former valve. 4. A mechanism for switching the lift amount of an intake valve,
An intake device for an internal combustion engine, comprising: a valve for controlling an air flow. 5. An intake system for an internal combustion engine, wherein a variable involved in combustion of the internal combustion engine is controlled on the basis of characteristic change information of a lift amount of the intake valve.