JPH0357804A - Direct type valve system - Google Patents

Abstract

PURPOSE:To enlarge a control range and to improve control accuracy by constructing a direct type valve system in a way that a pause of a valve is judged to fully open the electromagnetic relief valve of a predetermined valve and valve timing corresponding to various operating conditions is determined to variably control relief quantity. CONSTITUTION:At the time of operating an engine, in case that the cam 10 of a valve system 4 is on a base circle, oil is usually supplied from an oil pump 30 to the hydraulic chamber 24 of a hydraulic lifter 20, one of the oil is relieved at an electromagnetic relief valve 34 and the oil is filled up to predetermined volume. The cam 10 is rotated by a camshaft 9 to be lifted and thereby the cam piston 22 of the hydraulic lifter 20 is shifted. The electromagnetic relief valve 34 is closed by a control unit 45 under predetermined timing to produce high pressure inside to press a lifter piston 23. As a result, an intake/exhaust valve 3 is lifted in opposition to a valve spring 8 to be opened directly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a direct valve operating system using a hydraulic lifter in a vehicle engine, and more particularly to control of valve deactivation and variable valve timing.

[Conventional technology]

In general, vehicle engines tend to have wider operating ranges due to the higher output of multi-valve systems, but with this multi-valve system, combustion is possible at low and medium loads, including idling. In order to maintain good fuel economy, etc., it is necessary to appropriately control the intake air using valves. As this intake control, a valve suspension for temporarily stopping one of a plurality of intake and exhaust valves of a multi-valve system and variable control of valve timing have been proposed, and there is a method in which these are performed hydraulically.

Conventionally, regarding the above-mentioned pressure-pressure type valve stop, there is a prior art, for example, disclosed in Japanese Patent Application Laid-Open No. 58-53656, in which a hydraulic chamber is provided on the fulcrum side opposite to the valve in the rocker arm of the valve train, and the hydraulic pressure in this hydraulic chamber is controlled. It is shown that the valve changes and the valve deactivates.

Regarding hydraulic variable valve timing, for example, there is a prior art disclosed in Japanese Patent Laid-Open No. 61-93216, in which a hydraulic lifter is provided between the valve and the cam, and the hydraulic pressure in the high-pressure oil chamber of the hydraulic lifter is used to supply and drain oil. It is shown that the valve timing is controlled in two steps by changing the timing.

[Problem to be solved by the invention]

By the way, in all of the above-mentioned prior art, only one of valve suspension and variable valve timing is controlled by ON/OFF control of hydraulic pressure. In addition, in order to simplify the multi-valve system, a direct type like the latter of the prior art is desirable, but if the pressure receiving area of the hydraulic lifter cam and the valve are equal as in this prior art, then the valve The valve timing control range is limited by the cam lift amount as well as the lift amount, and there are problems such as difficulty in performing optimal control over a wide range.

The present invention has been made in view of the above points, and its purpose is to configure the volume of a hydraulic lifter to be controllable over a wide range, and to stop valves in accordance with each operating condition in a direct type using this hydraulic lifter. The object of the present invention is to provide a direct type valve operating device that can optimally control valve timing and valve timing.

[Means to solve the problem]

In order to achieve the above object, the direct type valve train of the present invention is a multi-valve direct type valve train in which two or more valves on the intake and exhaust sides are each provided with a cam and a hydraulic lifter. The hydraulic lifter of each valve has a large-diameter cam piston that contacts the cam side and a small-diameter lifter piston that contacts the valve side that fit into the fixed side lifter body,
A hydraulic chamber is formed inside these, and an electromagnetic relief valve that controls the amount of relief by a signal from a control unit is provided in the relief passage of the hydraulic chamber. The system fully opens the electromagnetic relief valves, determines valve timing according to each operating condition, and variably controls the relief amount of the electromagnetic relief valves of all valves.

[For production]

Based on the above structure, the valve lift state of each valve of the multi-valve direct valve operating system is controlled arbitrarily by changing the effective volume along with the relief amount of the hydraulic lifter using the electromagnetic relief valve. . When the control unit determines that the valve is inactive, such as during idling, the predetermined valve stops by controlling the effective volume of the hydraulic lifter to zero by fully opening the electromagnetic relief valve. . In addition, the control unit variably controls the relief amount of the electromagnetic relief valve and the effective volume of the hydraulic lifter for the valves that open and close during idling, and for all other valves under other conditions, making it ideal for each operating condition. The valve timing is now controlled by the correct valve timing.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

In Fig. 1, the symbol l is the cylinder head, 2 is the intake (exhaust) port, 3 is the intake (exhaust) valve, 4 is the valve mechanism, and the intake (exhaust) valve 3 is the cylinder head i. The umbrella portion 3a is supported by the valve guide 5 and is brought into contact with the valve seat 6, and the valve spring 8 is attached to the retainer 7 of the stem end 3b so as to bias the intake (exhaust) valve 3 in a direction to close it.

The valve mechanism 4 includes a stem end 3b of the intake (exhaust) valve 3.
A cam 10 of a camshaft 9 is coaxially arranged on the side, so that the valve can be opened and closed in a direct manner.

Therefore, a hydraulic lifter 20 for valve suspension and variable valve timing is interposed between the intake (exhaust) valve 3 and the cam TO. This pressure lifter 20 has a cup-shaped glue lid body 2 in a recess 11 behind the valve spring 8 of the cylinder head l, at a position that does not interfere with the retainer 7.
1 is pressed and fitted.

The lifter body 21 has a small diameter cylindrical portion 2lb at the center of the bottom of the large diameter cylindrical portion 21a.
The cam piston 22 with a large pressure-receiving area touches the bottom of the cam lO
A lifter piston 23 with a small pressure-receiving area is fitted into the small diameter cylindrical portion 2lb with its bottom facing toward the intake (exhaust) valve 3 side. In this way, a hydraulic chamber 2 is formed between the cam piston 22 and the lifter piston 23 inside the lifter body 21.
4 is formed, a cam piston 22 and a lifter piston 23
A spring 25 is biased between the two. The cam lO is in sliding contact with the cam piston 22, and the lifter piston 23
is in contact with the stem end 3b side of the intake (exhaust) valve 3, thereby increasing the lift amount l of the cam 10.
1, the volume of the hydraulic chamber 24 V. The intake (exhaust) valve 3 is lifted according to the ratio (AI/A2) of the pressure receiving area A1 of the cam piston 22 and the pressure receiving area A2 of the lifter piston 23. That is, the lift amount 12 of the intake (exhaust) valve 3
Ha, j! 2-A1/A2
1 and the pressure receiving area A2 of the lifter piston 23 (AI/
A2) doubles the effect. Furthermore, by completely relieving the hydraulic chamber 24, its volume V is reduced to 11 by the cam lift amount.
The valve will contract below and the valve will not lift substantially, and the valve will also stop.

On the other hand, the above-mentioned lifter piston 23 is provided with measures to reduce valve seating noise, and as a countermeasure, when the intake (exhaust) valve 3 is retreated by the valve spring 8, a stopper is installed between the lifter piston 23 and the small diameter cylindrical portion 2lb. 21c causes oil to be trapped, thereby absorbing the impact force when the intake (exhaust) valve 3 is seated. Further, an adjuster piston 26 is inserted into the lifter piston 23, and a high pressure chamber 28 is provided via a check valve 27 in the passage 23a.
Absorbs expansion and contraction of the valve and adjusts the valve clearance to zero.

Regarding the hydraulic system, a passage 31 from the oil pump 30 communicates with the hydraulic chamber 24 via a check valve 32, and an electromagnetic relief valve 34 is provided in a relief passage 33 of the hydraulic chamber 24. The relief amount of the electromagnetic relief valve 34 is controlled by a signal from the control unit 45, and the effective volume of the hydraulic chamber 24 is variably controlled.

In FIG. 2, an example will be described in which the multi-valve system is applied to a four-valve system.

Reference numeral 35 indicates a combustion chamber, and this combustion chamber 35 includes two intake boats 21, 2l' and two intake valves 31, 2l'.
3l' and two further exhaust boats 2e, 2e.
In addition to ', two exhaust valves 8e and Be' are provided. And intake valve 31,! 11', intake side cams 10t, iot' and hydraulic lifters 201, 20
1' are independently connected, and exhaust side cams 10e. 10e' and hydraulic lifter 20e
．． 20e' are independently connected, and the intake side electromagnetic relief valves 341 and 341' and the exhaust side electromagnetic relief valve 94e
．． 34e' can be controlled separately.

In FIG. 3, the control unit 45 will be described.

First, it has a crank angle sensor 36 that detects the engine speed Ne, an air flow meter 37 that detects the intake air amount Q according to the load, a cam angle sensor 38 that discriminates the cylinder, a throttle opening sensor 39, and a water temperature sensor 40. The engine speed Ne of the crank angle sensor 3B and the intake air amount Q of the air flow meter 37 are manually inputted to the operating condition determining means 46, and each operating condition is determined from the relationship between the engine speed Ne and the intake air mQ, and this signal is is input manually to the valve timing determining means 47. In the valve timing determining means 47, a valve timing map as shown in FIG. Slightly retard the valve timing to make the opening angle medium, and at high speeds and high loads, increase the opening angle without retarding the valve timing. A signal of the valve opening angle φ corresponding to the valve timing is manually inputted to the electromagnetic relief valve opening/closing timing setting means 48, and this electromagnetic relief valve opening/closing timing signal is sent to the driving means 491. 491' and 49e, 4
9e' manually and solenoid relief valves 941, 341'
and 34e. 34e'.

Further, the throttle opening degree θ of the throttle opening degree sensor 39 is inputted to the acceleration detecting means 50 and the acceleration is detected, and the timing correction amount 8T is determined by the correction amount setting means 5l. Further, the water mt of the water temperature sensor 40 is inputted to a similar correction amount setting means 52 to determine the timing correction amount ΔT1, and these timing correction amounts ΔT, , ΔT are inputted to the electromagnetic relief valve opening/closing timing setting means 48 to determine the timing correction amount ΔT1. Correct the opening/closing timing. Furthermore, the cylinder discrimination signal of the cam angle sensor 38 is manually inputted to the driving means 491, etc., and outputs an opening/closing signal to the corresponding electromagnetic relief valve.

On the other hand, the signals from the operating condition determining means 46 and the water temperature sensor 40 are input to the valve suspension determining means 53, which determines whether or not the valve is suspended in the idling state during warm-up.

This valve stop signal is sent to one drive means 491', 49e on the intake side and the exhaust side, and outputs a valve open hold signal.

Next, the operation of the direct type valve train having such a structure will be described.

First, during engine operation, when the cam lO is at the base circle, the oil pump 30 is connected to the pressure chamber 2 of the hydraulic lifter 20.
4 is always supplied with oil, and is partially relieved by an electromagnetic relief valve 34 to be filled to a predetermined volume Vo. Therefore, when the cam 10 of the valve mechanism 4 is rotated and lifted by the cam 9, the large diameter cam piston 22 of the hydraulic lifter 20
The pressure movement begins. When the electromagnetic relief valve 34 closes at a controlled timing, high pressure is generated inside, resulting in an effective volume v. From this point on, the pressing force doubles and acts on the small-diameter lifter piston 23 due to this high pressure and the pressure-receiving area ratio. Therefore, the intake (exhaust) valve 3 is lifted against the valve spring 8 by the pressing force of the lifter piston 23 at a predetermined timing, and is opened directly. On the other hand, in the base circle of the cam 10, the intake (exhaust) valve 3 is moved back by the valve spring 8 and is closed.

Thus, in the four valves of FIG. 4, two intake valves 31. 31' and exhaust valves 3e, 3e'
However, the intake side cams 101, 101' and the exhaust side cam I
lle10e' and hydraulic lifters 20+, 20i' and 20e, 20e' open and close in the same manner.

During such engine operation, signals of the engine speed Ne and the intake air amount Q according to the load are manually input to the operating condition determining means 46 of the control unit 45, each operating condition is determined, and this signal is sent to the valve stop determining means 53, The valve timing determining means 47 is manually operated. Therefore? When the engine is idling, it is determined that the valve is inactive, and the driving means 49I'. 4
9e to electromagnetic relief valve 341'. A valve open hold signal is output to '34e, and the hydraulic lifter 201', 20e
Fully open relief and no pressing force will be generated. For this reason,
The cams Lot' and 10e simply idle, and each one of the intake valves 31' and the exhaust valve 3e is closed and at rest.

On the other hand, at this time, the valve timing determining means 47 sets the valve opening angle φ to be small according to this condition, and accordingly also sets the electromagnetic relief valve opening/closing timing, and the driving means 491 . 49e' to electromagnetic relief valve 341,
34e' and two hydraulic lifters 20i, 20e.
The effective volume VB of ' is controlled to be small. For this reason cam lo
t and 10e', each of the intake valves 31' and the exhaust valves 3e lifts with a large delay, and as a result, the lift characteristics are changed to curve Ll in FIG.
The valve timing has a small valve opening angle φ, such as gX, Ll■N.

In this way, during idling, the valve opening angle φ also decreases in accordance with the intake air mQ, and each one of the intake valves 31' and the exhaust valve 3e is at rest, so that the intake air from the intake valve 3I creates a strong swirl inside the cylinder. Burns stably and well.

On the other hand, when the engine speed Ne and the intake air jlQ increase and the engine exits from an idling state, etc., it is no longer determined that the valve is at rest, and the four driving means 491, 491' and 49e . An electromagnetic relief valve opening/closing timing signal is output from 49e'. For this reason, four extraction pressure lifters 2
Oi, 201' and 20e, 20e' are controlled to have equal effective volumes, and the two intake valves 31.
31' and two exhaust valves 3e and 3e' open and close to inhale and exhaust air. Here, when the engine speed Ne and the intake air amount Q increase, the relief amount of the electromagnetic relief valve 341 etc. decreases and the effective volume of the hydraulic lifter 201 etc. increases, so the valve lift starts in accordance with this increase in effective volume. The valve lift is now curve L 2F in Figure 5! X
+ L 3rlX + L 21N + L
It increases like 31F+. Therefore, the valve opening angle φ is also gradually widened, and in this way, the valve timing is variably controlled to be optimal for each operating condition, and on the high load side, the filling efficiency is improved by 4-valve operation and the valve opening angle is increased, resulting in output output. Up.

Although one embodiment of the present invention has been described above, it is not limited thereto.

〔Effect of the invention〕

As described above, according to the present invention, the effective volume of the pressure lifter of a direct type valve train can be controlled arbitrarily, so it is possible to control the valve stop and variable valve timing according to each operating condition. This makes it possible to achieve both combustion and fuel efficiency on the low-load side of the multi-valve system and high output on the high-load side.

Furthermore, the hydraulic lifter has different pressure receiving areas and is designed to double the valve lift relative to the cam lift, making it possible to downsize the cam and expand the valve timing control range for optimum results. can be converted into

Furthermore, control is facilitated because the control unit determines whether the valve is inactive, determines the valve timing, and variably controls the opening/closing timing of one electromagnetic relief valve.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing an embodiment of the direct valve operating system of the present invention, Fig. 2 is a developed view showing the case where it is applied to 4 valves, Fig. 3 is a block diagram of the control unit, and Fig. 4 is a valve diagram. A diagram showing a timing map, FIG. 5 is a diagram showing a variable valve timing state. 3...Intake (exhaust) valve, 3i, 8t'...Intake valve, 3a, 3e'...Exhaust valve, 10,l
Ol. 10+', lOe, lOe'...cam, 20,
201, 201', 20e, 20e'...Lift pressure lifter, 22...Cam piston, 23...Lifter piston, 24...Hydraulic chamber, 34,341,341',
34e, 34e' ---Solenoid relief valve, 45...
Control unit, 47... Valve timing determining means,
53...Valve stop determination means

Claims (1)

[Claims] In a multi-valve direct type valve operating system in which a cam and a hydraulic lifter are connected to two or more valves on the intake and exhaust sides, the hydraulic lifter of each valve is mounted on a fixed side lifter body. A large-diameter cam piston in contact with the cam side and a small-diameter lifter piston in contact with the valve side are fitted together, a hydraulic chamber is formed inside these, and the relief amount is controlled by a signal from a control unit in the relief passage of the hydraulic chamber. The control unit determines whether to stop the valve, fully opens the solenoid relief valve of a predetermined valve, and further determines the valve timing according to each operating condition to fully open the solenoid relief valve of a predetermined valve. A direct valve operating device characterized by variable control of the relief amount of an electromagnetic relief valve.