JP2964812B2 - Intake / Exhaust Valve Control System for Inactive Cylinder in Multi-Cylinder Internal Combustion Engine with Variable Working Cylinder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for controlling intake and exhaust valves of a stopped cylinder in a multi-cylinder internal combustion engine in which the number of working cylinders can be changed in accordance with an operation state for energy saving.

[0002]

2. Description of the Related Art Conventionally, various types of variable-cylinder multi-cylinder internal combustion engines have been proposed. However, when the operation of a stopped cylinder is resumed, (a) the combustion flame is cooled by a relatively low-temperature cylinder wall surface. As a result, the quench area becomes larger, and the amount of unburned coal-fired hydrogen emission increases. (B) The lubricating oil staying at the top of the piston is exhausted due to the oil ascending, and the amount of unburned hydrocarbon emissions increases. (C) The fuel that has accumulated in the intake port is sucked, and the air-fuel ratio becomes too rich, causing poor combustion and deteriorating exhaust components. And other drawbacks.

Therefore, for example, Japanese Patent Application Laid-Open No. 56-132434.
A multi-cylinder internal combustion engine has been proposed as disclosed in Japanese Patent Application Laid-Open Publication No. H11-209,873.
In the non-operating cylinder of the multi-cylinder internal combustion engine, only the exhaust valve is opened and closed as appropriate while the inflow of intake air to the combustion chamber is blocked, so that exhaust gas is circulated in the combustion chamber.

[0004]

However, in this multi-cylinder internal combustion engine, the above-mentioned drawbacks (a) and (b) can be eliminated, but the exhaust gas component deteriorated due to the fuel retained in the intake port shown in the drawback (c). Cannot be prevented.

The present invention not only opens and closes an exhaust valve in a specific range in a deactivated cylinder, but also opens and closes an intake valve in a specific range related to opening and closing of an exhaust valve in consideration of a decrease in cylinder temperature due to inflow of intake air. It aims to eliminate the disadvantages of the previous term.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a variable-cylinder multi-cylinder internal combustion engine in which some of the cylinders are deactivated according to operating conditions. A valve operating means for opening and closing the intake valve of the port, and an intake / exhaust valve opening / closing timing changing means described below are provided. The exhaust valve opening / closing timing changing means sends an exhaust valve open signal to the valve actuating means in a process in which the piston of the deactivated cylinder moves from the top dead center to the bottom dead center, and in a process in which the piston moves from the bottom dead center to the top dead center. An exhaust valve closing signal is sent to the valve operating means. The intake valve opening / closing timing changing means sends an intake valve opening signal to the valve actuating means in a stroke in which the piston of the inactive cylinder moves from bottom dead center to top dead center, and sends an intake valve closing signal near the top dead center in the same stroke. Send to operating means.

[0007]

In the deactivated cylinder, when the exhaust valve starts to open in the stroke where the piston moves from top dead center to bottom dead center, exhaust gas is introduced into the combustion chamber through the exhaust port, and the piston is moved from bottom dead center to top dead center. When the exhaust valve closes and the intake valve opens and closes in the process of moving to, the exhaust gas introduced into the combustion chamber circulates to the intake port. The circulating action not only removes the lubricating oil staying at the top of the piston, but also removes the fuel staying in the intake port. At this time, the circulating exhaust also suppresses a decrease in the temperature of the idle cylinder.

[0008]

An embodiment of the present invention will be described below with reference to the drawings. As schematically shown in FIG. 1, the present embodiment is embodied in a four-cycle in-line four-cylinder engine, and includes a first cylinder 1, a second cylinder 2, a third cylinder 3, and a fourth cylinder 4 on a crankshaft 5. 6 is a cylinder, 7 is a piston, 8 is a combustion chamber, 9 is an exhaust port, 10 is an exhaust valve, 11 is an intake port, 12 is an intake valve, 13 is a fuel injection nozzle, and 14 is a spark plug. At a crank angle of 180 degrees, ignition occurs every half rotation. The ignition is performed in the order of the first cylinder 1, the third cylinder 3, the fourth cylinder 4, and the second cylinder 2.

Next, a drive control device for the exhaust valve 10 and the intake valve 12 will be described in detail with reference to FIG. The exhaust valve 10 and the intake valve 12 are urged by valve springs 15 and 16, respectively, and close the exhaust port 9 and the intake port 11 by the urging force. The exhaust valve 10 and the intake valve 12 are connected to hydraulic actuators 17, 18, and are opened and closed under the control of the hydraulic actuators 17, 18.

[0010] The hydraulic circuit H for operating the respective hydraulic actuators 17, 18 and the exhaust valve actuating circuits H ₁ including a hydraulic pump system circuit H _3, an intake air valve actuating circuit H ₂ including a hydraulic pump system circuit H ₃ And divided into In the hydraulic pump system circuit H _3, the hydraulic pump 19 is driven by an engine (not shown), the hydraulic tank 20 at its suction side
Through a strainer 21. Note that 22
Is a relief valve.

[0011] In the exhaust valve actuating circuit H _1, the hydraulic pump 19 is connected to the electromagnetic switching valve 24 for opening valve through a high-pressure accumulator 23 at its discharge side, the electromagnetic switch valve 24 is the exhaust valve for this opening It is connected to the side hydraulic actuator 17. The valve closing electromagnetic switching valve 25 is connected to the valve opening electromagnetic switching valve 24 and the exhaust valve side hydraulic actuator 17 and connected to the actuator 17, and the valve closing electromagnetic switching valve 25 is connected via a low pressure accumulator 26. It is connected to the hydraulic tank 20.

Meanwhile, the intake valve actuation circuit H ₂ includes a high pressure accumulator 27 and the valve opening selector valve 28 and valve-closing electromagnetic switching valve 29 and the low-pressure accumulator 30, their circuitry operates the exhaust valve it is similar to the use circuit H _1.

In the electric block circuit E, a throttle position sensor 31 is provided with a throttle valve (not shown).
The operation state (low load state or high load state) of the engine is detected from the opening degree of, and the signal is output to the valve controller. The valve controller 34 determines whether the load is low or high based on the input signal from the throttle position sensor 31.

The crank angle reference position detection sensor 32 generates a predetermined number of pulses for each rotation, detects an accurate crank angle for each predetermined angle based on the pulses, and outputs a signal to the valve controller 34. Valve controller 34
Calculates the crank angle based on the input signal from the crank angle reference position detection sensor 32.

The cylinder discriminating crank angle sensor 33 generates a pulse at the top dead center of the piston 7 that moves from the exhaust stroke to the intake stroke in each of the cylinders 1, 2, 3, and 4, and outputs a signal to the valve controller 34. Valve controller 34
Counts a predetermined number of pulses from the crank angle reference position detection sensor 32 based on an input signal from the cylinder discriminating crank angle sensor 33 sent for each of the cylinders 1, 2, 3, and 4.

[0016] In the exhaust valve actuating circuit H _1, the solenoid 25 of the solenoid 24a and the closing selector valve 25 of the valve-opening electromagnetic switching valve 24 from the valve controller 34
When the valve opening signal is sent to each of the solenoids 2a.
4a is excited to open the electromagnetic switching valve 24, and the solenoid 25a is demagnetized to close the electromagnetic switching valve 25. Therefore, the hydraulic pump 19 and the hydraulic actuator 17 communicate with each other, and the exhaust valve 10 opens against the elastic force of the valve spring 15. On the other hand, when a valve closing signal is sent from the valve controller 34 to these solenoids 24a, 25a, the solenoid 24a is demagnetized and the electromagnetic switching valve 24 is closed, and the solenoid 25a is excited to open the electromagnetic switching valve 25. Therefore, the hydraulic pump 19 and the hydraulic actuator 17
And the hydraulic actuator 17 and the hydraulic tank 20 communicate with each other, and the exhaust valve 10 is closed by the elastic force of the valve spring 15. The opening time and the lift amount of the exhaust valve 10 are determined by the time between the valve opening signal and the valve closing signal from the valve controller 34.

The opening / closing control of the intake valve 12 in the intake valve operating circuit H ₂ is performed by controlling a solenoid 28 a of a valve opening electromagnetic switching valve 28 and a solenoid 29 a of a valve closing electromagnetic switching valve 29 from a valve controller 34 by a valve opening signal. By sending a valve closing signal, the opening and closing control of the exhaust valve 10 is performed in the same manner.

The valve controller 34 controls each of the cylinders 1, 2, 3, 4 for a high load state and a low load state, respectively.
The output timing of the valve-opening signal and the valve-closing signal is stored for each count pulse.

When the valve controller 34 determines that the engine is in a high load state based on the input signal from the throttle position sensor 31, the valve controller 34 outputs a valve opening signal and a valve closing signal under a high load to the electromagnetic switching valve 24 for valve opening. The solenoids 24a, 28a of the solenoid valve 28 and the solenoids 25a, 29a of the electromagnetic switching valves 25, 29 for valve closing are sent. Therefore, each cylinder 1,
Open / close control of the exhaust valve 10 and the intake valve 12 for each of 2, 3, and 4 under a high load state is performed. FIG. 3 shows a valve timing diagram for each of the cylinders 1, 2, 3, and 4. If this is expressed as a relationship between the crank angle count pulse and the valve lift amount for each of the cylinders 1, 2, 3, and 4, it becomes as shown by the broken line in FIG.

On the other hand, when the valve controller 34 determines that the engine is in a low load state based on the input signal from the throttle position sensor 31, the valve opening signal of the second cylinder 2 and the third cylinder 3 in the high load state is determined. And a signal similar to the valve closing signal is transmitted to the solenoids 24a, 28a, and 25.
a, 29a, the first cylinder 1 and the fourth cylinder 4 send the valve opening signal and the valve closing signal in the low load state to the solenoids 24a, 28a, 25a, 29a. Accordingly, only the second cylinder 2 and the third cylinder 3 perform the normal operation, and the first cylinder 1 and the fourth cylinder 4 are in a rest state. Incidentally, in these idle cylinders 1 and 4, the fuel injection nozzle 13 and the spark plug 14 are stopped.

In particular, in the idle cylinders 1 and 4, the valve timings of the exhaust valve 10 and the intake valve 12 are changed, and FIG.
As shown by the solid line in FIG. That is, the exhaust valve 10
In the above, the piston 7 starts opening near the middle of the expansion stroke during the transition from the top dead center to the bottom dead center, and closes near the middle of the exhaust stroke when the piston 7 shifts from the bottom dead center to the top dead center.
Becomes the most open state near the bottom dead center. The lift amount of the exhaust valve in the low load state is smaller than the lift amount of the intake / exhaust valve in the high load state (broken lines in FIGS. 4A and 4D). In the intake valve 12, the piston 7 starts to open near the middle of the exhaust stroke where the bottom dead center shifts to the top dead center, and the piston 7 before the intake stroke shifts.
Closes near top dead center, and opens most in the middle of the latter half of the exhaust stroke. The intake valve lift in the low load state is smaller than the intake and exhaust valve lift in the high load state and is smaller than the exhaust valve lift in the low load state.

Although the intake valve 12 starts opening before the exhaust valve 10 closes near the middle of the exhaust stroke, the intake valve 12 may start opening immediately after the exhaust valve 10 closes.
In the deactivated cylinders 1 and 4, the exhaust valve 10 and the intake valve 12 are controlled to open and close in this manner, so that the piston 7
As the gas moves from top dead center to bottom dead center, the exhaust
The exhaust gas introduced into the combustion chamber 8 circulates to the intake port 11 as the piston 7 moves from bottom dead center to top dead center in the exhaust stroke. By the circulation action, not only the lubricating oil staying at the top of the piston 7 can be removed, but also the fuel staying at the intake port 11 can be removed. Since the circulating medium at that time is exhaust gas, it is possible to minimize the temperature drop of the deactivated cylinders 1 and 4 as much as possible. Therefore, the exhaust components are in a favorable state, for example, the emission amount of unburned hydrocarbons is reduced.

In another embodiment shown in FIG. 5, the opening and closing control of the exhaust valve 10 and the intake valve 12 in the deactivated cylinders 1 and 4 is changed. Although the opening and closing control of the exhaust valve 10 and the intake valve 12 is performed in the expansion stroke and the exhaust stroke in the above-described embodiment, focusing on the movement of the piston 7, the expansion stroke is the same as the intake stroke, and the exhaust stroke is the same as the compression stroke. Therefore, in the other embodiment, the opening and closing of the exhaust valve 10 and the intake valve 12 is controlled in the intake stroke and the compression stroke in the same manner as in the above-described embodiment.

In short, in the present invention, the deactivated cylinders 1,
The exhaust valve 10 starts to open when the piston 7 moves from the top dead center to the bottom dead center, and the exhaust valve 10 closes when the piston 7 moves from the bottom dead center to the top dead center. A multi-cylinder internal combustion engine characterized in that it starts to open near the closed position of the valve 10 and then closes near the top dead center and can perform such opening and closing control without departing from the scope of the present invention. It may be applied to various types of internal combustion engines.

[0025]

According to the variable cylinder type multi-cylinder internal combustion engine of the present invention, since the exhaust gas introduced from the exhaust port to the combustion chamber in the idle cylinder circulates also to the intake port, the lubrication oil stays at the top of the piston. Not only to prevent fuel and cylinder temperatures from dropping, but also to prevent fuel stagnation at the intake port,
The exhaust components can be kept in a good state.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a four-cycle in-line four-cylinder engine according to an embodiment.

FIG. 2 is an electrohydraulic circuit diagram showing a valve opening / closing control device for each cylinder in the engine.

FIG. 3 is a valve timing diagram in a high load state in the engine.

FIG. 4 is an operation characteristic diagram of an exhaust valve and an intake valve of each cylinder with respect to a crank angle in the engine.

FIG. 5 is another operating characteristic diagram.

[Explanation of symbols]

1 1st cylinder, 2nd cylinder, 3rd cylinder, 4th cylinder, 7 piston, 8 combustion chamber, 9 exhaust port, 1
0 exhaust valve, 11 intake port, 12 intake valve, 24
Valve opening electromagnetic switching valve, 25 Valve closing electromagnetic switching valve, 28 Valve opening electromagnetic switching valve, 29 Valve closing electromagnetic switching valve, 31 Throttle position sensor, 32 Crank angle reference position detection sensor, 33 Cylinder discriminating crank angle sensor 34, a valve controller as an intake / exhaust valve opening / closing timing changing means, and a hydraulic circuit as an H 2 valve operating means.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-58-172412 (JP, A) JP-A-58-176428 (JP, A) JP-A-58-195005 (JP, A) JP-A-58-195005 195006 (JP, A) JP-A-59-5846 (JP, A) JP-A-58-180742 (JP, A) JP-A-58-187508 (JP, A) JP-A-57-38639 (JP, A) JP-A-57-99241 (JP, A) JP-A-57-66251 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F02D 13/00-13/06 F02D 17/02

Claims (1)

(57) [Claims] 1. A variable-cylinder multi-cylinder internal combustion engine in which some of the cylinders are deactivated according to an operation state, valve operation means for opening and closing an exhaust valve of an exhaust port and an intake valve of an intake port in the deactivated cylinder. An exhaust valve open signal is sent to the valve operating means during the stroke in which the piston of the idle cylinder moves from top dead center to bottom dead center, and an exhaust valve closing signal is sent to the valve operating means during the stroke in which the piston moves from bottom dead center to top dead center. Means for changing the exhaust valve opening / closing timing to be sent to the valve operating means, and sends an intake valve opening signal to the valve actuating means in a stroke in which the piston of the deactivated cylinder shifts from bottom dead center to top dead center. And an intake valve opening / closing timing changing means for sending the intake valve opening / closing timing to a valve operating means.