JPS62243909A - Valve system controller for engine - Google Patents

Abstract

PURPOSE:To improve starting characteristics in a device for opening and closing intake and exhaust valves by a hydraulic actuator by maintaining the intake and exhaust valves under the closed condition from the beginning of start to the stable cranking and then closing the exhaust valve for a while. CONSTITUTION:High pressure oil from a pump 5 is supplied to hydraulic actuators 3, 4 for exhaust and intake valves 1, 2 by a distributor 6 in a predetermined time in synchronization with the rotation of engine. A lift stopping means 7 is operated by a rotational frequency detecting means 9 from the beginning of start to the stable cranking to maintain intake and exhaust valves 2, 1 under the closed condition. Thus, cooling the interior of a cylinder accompanying with intake and exhaust can be prevented. An exhaust valve controlling means 8 is operated during a predetermined period even after the stable cranking to maintain the exhaust valve 1 under the closed condition and unburnt gas or the like is burnt in the cylinder so that the temperature in a combustion chamber is raised.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a valve control device that opens and closes intake and exhaust valves of an engine.

(Prior art) Conventionally, as a valve mechanism that drives the opening and closing of intake and exhaust valves,
Products that use a camshaft have little freedom in opening and closing characteristics, so for example,
As shown in the above issue, a technique has been proposed in which a hydraulic cylinder is used to open and close a valve, and the valve is controlled with predetermined characteristics through hydraulic control.

On the other hand, for example, when cold starting a diesel engine, the amount of starting fuel is normally increased to promote starting. However, because the temperature inside the cylinder is low, the fuel that has not reached the ignition state and has reached a state of atomization or just before evaporation is discharged from the cylinder by the opening and closing operations of the exhaust valve and the intake valve. Repetition of this condition results in a longer start-up time.

(Object of the Invention) In view of the above-mentioned circumstances, an object of the present invention is to provide an engine valve control device 2 that improves cold startability by controlling the opening and closing of exhaust valves and intake valves. .

(Structure of the Invention) The valve control device of the present invention supplies oil under pressure by a pump to valve drive actuators for exhaust and intake valves through a distributor, and opens and closes the exhaust and intake valves. , a rotation speed detection means for detecting the engine rotation speed, a lift stop means for stopping the opening/closing operation of the exhaust valve and the intake valve from the start m1 until the cranking stable rotation speed is reached, and an exhaust valve after the cranking stable rotation speed is reached. The present invention is characterized by comprising an exhaust valve control means for keeping the exhaust valve in a closed state during some cycles.

FIG. 1 is a schematic configuration diagram for clearly showing the configuration of the present invention, which controls the opening and closing of the exhaust valve 1 and intake valve 2 in the air WIC of the engine E. A valve driving actuator 3.4 is provided which is driven to open and close by hydraulic pressure. The oil pumped by the pump 5 is supplied to the valve drive actuators 3 and 4 of each cylinder C via the distributor 6, and the opening/closing characteristics of the exhaust valve 1 and the intake valve 2 are adjusted by adjusting the oil pressure supplied from the distributor 6. Change control.

The operation of the distributor 6 is controlled by a lift stop means 7 and an exhaust valve control means 8. A detection signal from a rotation speed detection means 9 for detecting the engine rotation speed is output to the refj/stop means 7 and the exhaust valve control means 8.

The lift stop means 7 stops the opening/closing operations of the exhaust valve 1 and the intake valve 2 from the start of startup until the cranking rotation speed reaches a stable cranking rotation speed, while after the cranking rotation speed reaches a stable cranking rotation speed, the exhaust valve control means stops the operation. Exhaust valve 1 by
For example, it is controlled so that the opening operation is performed every predetermined cycle, and the opening and closing operation is stopped during some cycles to enter the closed state.

Note that the exhaust valve 1. is controlled by the lift stop means 7 and the exhaust valve control means 8. The opening/closing of f5 and the intake valve 2 can be performed by controlling the operation of the distributor 6, or by various means such as stopping the supply of hydraulic pressure to the distributor 6, or stopping the functions of the valve drive actuators 3 and 4.

(Effects of the Invention) According to the present invention, when starting the engine, first, the opening and closing operations of the exhaust valve and intake valve are stopped until the cranking stable rotation speed is reached, and the cranking valves are kept in the closed state. In addition to speeding up the start-up time, the oil pressure for driving the valve can be increased to ensure reliable operation at the start of the opening/closing operation. Furthermore, when a stable cranking speed is reached, the exhaust valve is partially closed in a predetermined cycle, thereby preventing the discharge of atomized unburned gas and increasing the actual in-cylinder fuel M, while increasing the temperature. By retaining the increased gas, the cylinder lag can be increased, improving the ignition conditions and achieving an early start, shortening the start time.
In general, warm-up performance can be improved.

(Example) The present invention will be described in detail below with reference to the drawings.

FIG. 2 is an overall configuration diagram of a specific example.

The exhaust valve 1 that opens and closes the exhaust port 11 formed in the cylinder head 10 of the engine E and the intake valve 2 that opens and closes the intake boat 12 each have a valve spring 13.13.
While the exhaust valve 1 and the intake valve 2 are biased in the valve closing direction by
pistons 3a and 4a are connected to each other, and when hydraulic pressure is supplied to the valve drive actuator 3.4, the exhaust valve 1 and the intake valve 2 are opened against the pulp spring 13.13. Leak passages 3b and 4b are connected to the valve drive actuator 3.degree.4 in correspondence with the maximum lift positions of the exhaust valve 1 and the intake valve 2, respectively.

The oil pressure feed passage 16.16 that supplies hydraulic pressure to the valve drive actuators 3, 4 is connected to a distributor 6, and a hydraulic pressure supply passage 21 from the oil pump 5 is connected to the distributor 6 via a high pressure tank 19. has been done. The oil from the dedicated oil tank 22 and the insufficient amount of oil are sucked and supplied to the oil pump 5 from an oil pan 23 via a filter 24. Drive shaft 5 of the above oil pump 5
a is driven from the drive shaft 25 of the engine via the transmission member 26, pressurizes oil and stores it in the high pressure tank 19.

Hydraulic pressure supply passage 2 leading from the high pressure tank 19 to the distributor 6
1 is interposed with an opening/closing valve 20 which is a solenoid valve that opens and closes the hydraulic pressure supply passage 21.

Further, the distributor 6 has a shaft 27 that is connected to the drive shaft 25.
It is driven to rotate in synchronization with the rotation of the engine, and opens the exhaust valve 1 and intake valve 2 by force-feeding hydraulic pressure to the valve drive actuator 3.4 of the exhaust valve 1 and intake valve 2 at a predetermined time. A drain passage 28 is connected from the distributor 6 to the oil tank 22.

Further, control signals from the control unit 30 are outputted to the distributor 6 and the opening/closing valve 20, respectively, so that the hydraulic pressure feeding timing can be adjusted. The control unit 30 receives a signal from a rotation speed sensor 31 that detects the engine rotation speed and a water temperature sensor 32 that detects the engine temperature from the engine cold water temperature in order to determine the stable rotation speed during starting and cranking. signals are respectively input.

During normal operation, the control unit 30 controls the opening and closing operations of the exhaust valve 1 and the intake valve 2 so that they are fully opened at a predetermined valve opening timing and fully opened at a predetermined valve closing timing.

Also, at the time of starting, the stable cranking rotation speed (for example, 10
0 to 200 rpm), the on-off valve 20 is set to the m1 state, the supply of hydraulic pressure to the distributor 6 is stopped, and the hydraulic pressure is not supplied to the valve drive actuators 3.4 of the exhaust valve 1 and intake valve 2. , the opening/closing operations of both valves 1.2 are stopped to maintain the valves in the closed state. After reaching a stable cranking speed, the intake valve 2 opens and closes as usual under the condition that the water temperature is, for example, 80 degrees Celsius or less in a predetermined idle rotation range, while the exhaust valve 1 opens and closes as usual at each predetermined cycle. By repeating the supply of hydraulic pressure to the valve drive actuator 3 of No. 1 and the opening of the drain, a predetermined cycle (
For example, the exhaust valve 1 is controlled to be opened and closed once every 2 to 3 cycles. Note that the closing cycle and opening cycle of the exhaust valve 1 are set within a range in which the residual gas can maintain the air-fuel ratio necessary for combustion of the fuel.

The specific structure of the distributor 6 in an example of a four-cylinder engine is shown in FIGS. 3 to 8. The rotation of the drive shaft 25 is transmitted to the shaft 27 of the distributor 6 by a pulley 35,
It is driven to rotate in synchronization with the engine rotation so that it rotates once every two revolutions.

A hydraulic pressure supply passage 21 from the high pressure tank 19 is communicated with a first passage 37 in a shaft 27 via a first spill ring 36 . The structure of the oil passage in the first spill ring 36 is as shown in FIG. Eight inlet boats 3 corresponding to the exhaust valve 1 and intake valve 2 of each cylinder
7a are formed radially at approximately equal intervals corresponding to the phases of the eight valves, and are gathered in the first passage 37 at the center. That is, during one rotation of the shaft 27, the boat 36a of the first spill ring 36 communicates with the inflow side boat 37a of the shirt 1-27 eight times, and high-pressure oil flows into the first passage 37. In addition, the first spill ring 36 has a lever portion 36b extending downwardly connected to the pinion shaft 3 of the first motor 38.
8a so that the phase with respect to the shaft 27, that is, the timing of inflow and outflow of high pressure oil can be changed.

The discharge boat 37b of the first passage 37 is connected to the oil pressure feeding passage 1 to the valve drive actuator 3.4 of the exhaust valve 1 and intake valve 2 of each cylinder via the second spill ring 39.
Connected to 6. As shown in FIG. 5, the structure of the oil passage in the second spill ring 39 is such that one discharge boat 37b is provided from the first passage 37 of the shaft 27, and the second spill ring 39 has a exhaust valve 1
Eight boats 39a corresponding to the OJ and intake valves 2 are formed radially at approximately equal intervals corresponding to the phase of the joint venture, and an oil pressure feeding passage communicating with each boat 39a is provided on the outer periphery of the second spill ring 39. 16 is connected, and pressure-feeds oil to the valve drive actuators 3.4 of the exhaust valves 1 and intake valves 2 of each cylinder.

The number of each cylinder is shown as #1 to #4, and e for exhaust valve 1 is shown.
x is shown with a subscript 1n for the intake valve 2, respectively.

With the above structure, oil is sequentially supplied to the exhaust valve 1 and intake valve 2 of each cylinder during one rotation of the shaft 27. Further, the second spill ring 39 is engaged with a lever portion 39bS extending downward and a binion shaft 40a of the second motor 40, so that the phase with respect to the shaft 27, that is, the timing at which pumping of high-pressure oil starts can be changed. There is.

Furthermore, a check valve 41 for preventing backflow of oil to the first passage 37 is interposed in the oil pressure feeding passage 16 .

A check valve 41 is provided in the oil pressure passage 16 that pressure-feeds operating oil between the exhaust valve 1 and intake valve 2 of each cylinder C.
Relief passages 42 are connected to the downstream side, and each relief passage 42 is connected to a second passage 44 in the shaft 27 via a third spill ring 43. This third
The structure of the oil passage in the spill ring 43 is as follows:
As shown in FIG. 6, one relief boat 44a is provided in the second passage 44 of the shaft 27, and this relief boat 44a extends in the opening direction of the discharge boat 37b of the first passage 37 (see FIG. 5). It is formed so as to be tilted toward the rotation rearward by a predetermined phase (approximately 45 degrees). Eight boats 43a corresponding to the exhaust valves 1 and intake valves 2 of each cylinder C are formed radially in the third spill ring 43, and the relief passages communicate with the respective boats 43a on the outer periphery of the third spill ring 43. 42 is the oil pressure feeding passage 16
The valve drive actuators 3.4 of the exhaust valves 1 and intake valves 2 of each cylinder are connected in a similar arrangement, and the oil is relieved from the oil pressure feeding at a predetermined phase. Further, the third spill ring 43 is provided so that a lever portion 43b extending downward engages with the binion shaft 45a of the third motor 45, so that the phase with respect to the shaft 27, that is, the timing at which relief of high-pressure oil starts can be changed. There is.

The outflow side drain boat 44b of the second passage 44 is connected to the drain passage 28 via a fourth spill ring 46 fitted into the shaft 27. The structure of the oil passage in this drain boat 44b part is as shown in FIG. A drain boat 46b is formed with an annular groove 46a and communicates with the annular groove 46a and passes through the fourth spill ring 46.
is formed, and a drain passage 2 leading to the oil tank 22 is formed.
It is connected to 8. Both drain boats 44b and 46
b, the second passage 44 is always connected to the drain passage 28.

Roughly speaking, in order to stop the opening and closing operation of the exhaust valve 1 at a predetermined cycle, a drain valve 47 is installed to open the first passage 37 at a predetermined timing. That is, the drain boat 37C communicating with the first passage 37 is connected to the drain passage 28a via the fifth spill ring 48 fitted into the shaft 27, and the drain boat 37C communicates with the first passage 37.
A drain valve 47 is interposed therein. When this drain valve 47 is energized to the solenoid 47a, the valve body 47b
acts to open the drain passage 47a against the spring 47c.

The structure of the oil passage in the drain boat 37G portion of the first passage 37 is as shown in FIG.
From the first passage 37 of 7, the discharge boat 37b and the intake valve 2
When the boats 39a for the exhaust valve 1 communicate with each other, four drain boats 37C are radially provided in the phase communicating with each boat 39a for the exhaust valve 1, and the fifth spill ring 48
One drain boat 48a is formed at a position corresponding to the intake valve 2, and communicates with the drain passage 28a that joins the drain passage 28 leading to the oil tank 22. Through this communication between both drainboards 1" 370, 48a, the first
The passage 37 is connected to the drain passage 2 during hydraulic pressure feeding to the exhaust valve 1.
8a, and at the time of starting the machine when a stable cranking rotation speed has been reached, the drain is opened when the drain valve 47 is opened at a predetermined timing, and the supply of hydraulic pressure to the valve drive actuator 3 is stopped, and the exhaust valve is opened. 1.

The operation of the distributor 6 will be explained along the valve opening curve shown in FIG. In the state where the exhaust valve 1 of the first cylinder is opened under pressure, the discharge boat 37b of the first passage 37 of the shaft 27 supplies oil to the exhaust valve 1 of the first cylinder via the boat 39a of the second spill ring 39. It communicates with the pressure-feeding passage 16 (#1eX) and pressure-feeds the oil that has flowed into the first passage 37 from the first spill ring 36.

The opening timing of the exhaust valve 1 at point a is determined by the timing at which the discharge boat 37b of the shaft 27 and the boat 39a of the second spill ring 39 start communicating with each other by adjustment of the second motor 40. In addition, the lift width increases due to the increase in pressure, and the point b where the lift amount is the maximum is determined by the adjustment of the first motor 38.
a and the timing at which communication between the first spill ring 36 and the boat 36a ends.

Subsequently, as the shaft 27 rotates, the discharge boat 37b of the first passage 37 ends communication with the oil pressure feeding passage 16 (#1ex) for the exhaust valve 1 of the first cylinder, and then
In the state shown in Fig. 6 and Fig. 6, communication with the oil pressure passage 16 (#1 inch) to the intake valve 2 of the first cylinder is started at point e, and the relief passage 42 to the exhaust valve 1 of the first cylinder is started. (#1ex) is the relief boat 44a of the second passage 44 of the shaft 27 and the third spill ring 43.
Relief is started by communication with the boat 43a, and the relieved oil is drained through the drain passage 28. The zero point at which the lift Φ begins to decrease after the relief starts is the relief boat 44a of the shaft 27 and the boat 43a of the third spill ring 43, which are determined by the adjustment of the third motor 45.
The lift amount of the exhaust valve 1 decreases due to a decrease in the oil pressure applied to the valve drive actuator 3, and the exhaust valve 1 closes at point d.

When starting, b until the stable cranking speed is reached.
The exhaust valve 1 and the intake valve 2 are maintained in a closed state by stopping the oil pressure supply to the distributor 6 by the 1-closing valve 20, and when a stable cranking rotation speed is reached, the control unit 30 closes the drain valve 47 to a predetermined value. Opens and closes at the right time.

For example, when the shaft 27 rotates 2 to 3 times, the drain valve 47 is opened to drain the first passage 37 through the drain passage 28a, and then the drain valve 47 is closed while the shaft 27 rotates once. It is. As a result, while the drain valve 47 is open, the oil pressure applied to the valve drive actuator 3 of the exhaust valve 1 is reduced, and the opening operation becomes impossible, and the exhaust valve 1 is in a closed state.

Control signals are outputted from the control unit 30 to the motors 38, 40, 45 and the drain valve 47 of the distributor 6 to control opening/closing operations of the six valves and changes in valve lift characteristics.

FIG. 10 shows a control unit 30 that performs control to stop the valve lift of the exhaust valve 1 or the intake valve 2 during startup.
A part of the flowchart is shown below.

After the start, in step S1, detection signals of the engine rotation speed N and cold section water temperature T are read from the rotation speed sensor 31 and the water temperature sensor 32. In step S2, it is determined from the detection signal whether the engine rotational speed N is equal to or higher than the stable cranking rotational speed N1.

If the determination in step S2 is No, the engine speed N from the start of startup until it reaches the stable cranking speed NI,
The opening/closing valve 20 is maintained in the off state with the engine stopped, and the hydraulic pressure supply passage 21 is opened by the opening/closing valve 20.
The exhaust valve 1 and the intake valve 2 are closed.

Then, the engine speed N is the stable cranking speed N
When reaching s, the YES determination in step S2 above results in
In step S3, an on-signal is output to the opening/closing valve 20,
The hydraulic pressure supply passage 21 is opened by the on-off valve 20, and the exhaust valve 1 and the intake valve 2 are opened and closed.

Next, in step S4, it is determined whether the engine rotation speed N is equal to or lower than a predetermined idle rotation speed N2, and in step S
5, the water ffl T is the predetermined faT. Determine whether or not the value is lower. If the determinations in both steps S4 and S5 are YES, the drain valve 47 is repeatedly turned on and off at a predetermined timing in step S6, and the exhaust valve 1 is opened every predetermined cycle. On the other hand, the above step S4 or S
If the determination in step 5 is No, an off signal is output to the drain valve 47 in step S7, and the exhaust valve 1 and the intake valve 2 are turned off.
It opens and closes during every cycle.

According to the above embodiment, the opening/closing operations of the exhaust valve 1 and the intake valve 2 are temporarily stopped in response to the detection of the starting rotation speed, the engine start-up time is shortened, and the temperature inside the cylinder is increased, thereby improving the ignition conditions. It is possible to improve this and shorten the cooling start time.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram for clearly showing the configuration of the present invention, Fig. 2 is an overall configuration diagram of a specific example, Fig. 3 is a sectional view showing the schematic structure of the main part of the distributor, and Figs. 4 to 8 The figures are IV-IV line or ■ in Figure 3, respectively.
9 is a valve opening/closing characteristic diagram, and FIG. 10 is a flowchart for explaining the operation of the control unit. E...Engine C...Cylinder 1...Exhaust valve 2...Intake valve 3.4...Valve drive actuator 5...・
... Pump 6 ... Distributor 7 ...
... Lift stop means 8 ... Exhaust valve control means 9 ... Rotation speed detection means 16 ... Oil pressure feeding passage 19 ... High pressure tank 20. ...Opening/closing valve 27...
... Shaft 28.28a ... Drain passage 30 ... Control unit 31 ...
・Rotation speed sensor 32...Water temperature sensor 37・
...First passage 44...Second passage 38.40.45...Motor 42...Relief passage 47...Drain valve second Figure 4 Figure 5 Figure 6 Figure 8 Figure 9 Figure 1Q

Claims (1)

[Claims] (1) A valve control device for an engine in which oil pumped under pressure is supplied to actuators for driving exhaust and intake valves through a distributor, and the valve drive actuator opens and closes the exhaust and intake valves. a lift stop means that stops the opening/closing operation of exhaust valves and intake valves from the start of startup until a stable cranking speed is reached; 1. A valve control device for an engine, comprising: exhaust valve control means for closing the valve during a cycle.