JPH0364608A - Control device for valve timing lift - Google Patents

Abstract

PURPOSE:To enable an optimum switch-over mode to be set up for respective operating ranges by selectively switching a lift quantity switch-over means and a valve open timing switch-over means, thereby making it possible to secure 4 kinds of switch-over modes. CONSTITUTION:Respective paired suction and exhaust valves 43 and 44 which open/close respective paired suction and exhaust ports 40 and 42, are constituted to be opened/closed by way of a valve open timing switch-over means M1 and a lift quantity switch-over means M2 to both of which pressure oil is sup plied from a main oil gallery 3a respectively. The lift quantity switch-over means M2 is so constituted that the suction and the exhaust valve 43 and 44 are set at a high lift mode when a switch-over solenoid valve V1 is turned on, and are also set at a low lift mode when the valve is turned off. In addition, the valve open timing switch-over means M1 is constituted to control a twist angle by means of switch-over solenoid valves V2 and V3 with hydraulic pres sure controlled, which is supplied to a twist mechanism twisting respective cam shafts 31 and 32 toward timing gears 4i and 4e so that the respective switch-over means M1 and M2 are respectively controlled so as to be switched in response to engine operation conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a valve timing lift control device installed in a valve train of an internal combustion engine.

(Prior Art) Various operating conditions are set for internal combustion engines so that the engine output and fuel efficiency can be improved.

In particular, since the operating conditions of internal combustion engines for vehicles often change from moment to moment, engine output and fuel efficiency can be obtained efficiently at each point in time. Alternatively, the operating conditions for achieving engine stability are often different. The valve train system of a normal internal combustion engine is configured to open and close intake and exhaust ports of a fixed shape, and to open and close them over the entire operating range while maintaining a fixed lift amount and fixed valve timing.

For this reason, when setting fixed values, values that enable operation in the highest output and most frequently used range are often selected.As a result, operating efficiency decreases in operating ranges outside of the set operating conditions. As a result, the engine's output performance, etc., cannot be fully demonstrated.

Therefore, in order to always operate the internal combustion engine efficiently,
The valve timing or lift amount is adjusted by increasing or decreasing yA.

For example, a valve opening timing switching means as shown in Fig. 9 is installed in the valve train of an internal combustion engine, and the opening timing of the intake valve is advanced or retarded depending on a predetermined operating mode. .

Here, the valve opening timing switching means elbow incorporates a camshaft twisting mechanism. That is, the bearing 1 on the cylinder head (not shown)
A cylindrical inner cylindrical member 3 is attached and bolted to the end of the intake camshaft 2 which is pivotally supported by the cylindrical member 3, a boss portion 5 of the timing gear 4 is fitted onto the cylindrical member 3, and a boss portion 5 of the timing gear 4 is fitted onto the cylindrical member 3. A spline-like inclined tooth row 6 formed on the inner wall of the portion 5, a spline-like inclined tooth row 7 formed on the outer peripheral surface of the inner cylinder member 3 at a position facing the inclined tooth row 6, and a surface slope. Teeth row 6.7
A cam member 8 having internal and external teeth 781 and 702 that mesh with each other, a pressure receiving member 9 that applies a pressing force to the cam member 8, and a first
．． and second return springs 10 and 11.

This valve opening timing switching means transmits twisting hydraulic pressure supplied by a control system (not shown) to the pressure receiving member 9 through an oil passage 12 and a pressure chamber 13 in the camshaft 2, and the pressing force applied from this transmits the twisting hydraulic pressure to the cam member 8. moves to the right (in FIG. 9) against the elastic force of the first return spring 10. When the cam member 8 moves, the relative rotation direction of the camshaft 2 and the timing gear 4 can be shifted by the cooperative action of the pair of inclined tooth rows 6, 7 and the inner and outer tooth parts 701, 702. This can be increased or decreased in a timely manner.

Such a valve opening timing switching means changes the valve timing, which is the opening/closing timing of the intake and exhaust valves, to advance mode a or retardation mode based on the ON/OFF switching operation of the hydraulic pressure of the control system. You can switch to mode b. By selecting advance angle mode a in the low speed driving range, you can increase the low speed output, and by selecting retard angle mode b in the high speed driving range and when idling, you can prevent a decrease in fuel efficiency due to blowout at high speed. It is possible to ensure idle stability.

On the other hand, a lift amount switching means M2 is attached to the valve train of the internal combustion engine, and the lift amount of the intake valve is switched from large to small according to a predetermined operating range. Incidentally, as this lift amount switching means M2, the one disclosed in Japanese Utility Model Application Publication No. 63-67603 is known, and the related structure is described in the first section.
It is shown in Figure 1.

This lift amount switching means M2 is installed in a two-valve intake engine, and a high-speed cam 1 is mounted on a portion of the camshaft IS opposite to each cylinder.
7 and a pair of low-speed cams 18 sandwiching it, the rocker shaft 1
At the position facing the cam 9, there is a Mitsu rocker arm 20 driven by the high-speed cam 17, and a pair of primary rocker arms 21 and secondary rocker arms 22 that sandwich this.
A pair of first and second hydraulic pistons 23 and 24 are slidably supported within these rocker arms and movable in a direction parallel to the camshaft, and a second hydraulic piston 24 is supported within the secondary rocker arm 22. A return spring 25 that presses in the return direction via the slider 26 and an oil passage 2 formed within the primary rocker arm 21 and within the rocker shaft 19.
7 and a pressure chamber 28 communicating with the pressure chamber 7.

Such lift amount switching means M2 changes the lift amount and valve operating angles θe, θi of the intake and exhaust valves as shown in FIG.
It is possible to switch to a high lift mode C1 in which the amount of lift is kept large, or a low lift mode d in which the lift amount and valve operating angles θe and θi are kept small.

Here, by selecting the low lift mode d, it becomes easy to ensure idle stability and low-speed torque in the low-speed operating range, and by selecting the high lift mode C, it becomes easy to ensure the maximum output.

(Problem to be Solved by the Invention) In this way, the conventional device performs switching control of either the valve timing or the lift amount, but in either case, a single mode switching means is used. By switching, it was possible to achieve operation in a plurality of different switching modes. However, by simply switching such a single mode switching means, it is not possible to change the switching mode to more accurately improve engine output and fuel efficiency in response to changes in driving conditions, and improvements have been desired. .

An object of the present invention is to provide a valve timing lift control device that can more accurately improve engine output and fuel efficiency by selecting a more accurate switching mode in the operating range of the engine.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention provides a lift amount switching means that is attached to a valve train of an internal combustion engine and changes the lift amount of an intake valve, and and valve opening timing switching means that is attached to the valve opening timing and switches the opening timing of the intake valve.

An intake pressure sensor that emits intake pressure information of the internal combustion engine, a load sensor that emits output information of the internal combustion engine, a rotation sensor that emits rotation speed information of the internal combustion engine, and the intake pressure information, output information, and rotation speed information. and a controller that selectively switches and operates the lift amount switching means and the valve opening timing switching means so as to ensure at least four switching modes combined by switching the lift amount and valve opening timing based on the above. Features.

(Function) The controller selectively switches and operates the lift amount switching means and the valve opening timing switching means, thereby ensuring at least four switching modes that are combined by switching the lift amount and valve opening timing. , the optimum switching mode for each driving range can be selected.

(Example) The valve timing lift control device shown in Fig. 1 is a 4-air 11i
This is a four-cycle engine 30, and two intake and exhaust camshafts 31 and 32 for each cylinder are configured to rotate in response to the rotation of a crankshaft 33 via a timing belt 34.

Here, the hydraulic system 35 of the engine 30 guides the oil in the oil pan 36 to the main oil gear rally 39 via the gear pump 37 and filter 38.
Pressure oil is supplied to each lubricated part.

The engine 30 supplies fuel from a fuel system (not shown) to intake air from the intake system, and transfers the air-fuel mixture to a forked intake port 40.
through each intake cylinder SL, S2. S3. The exhaust gas is introduced into the combustion chamber 41 of S4, and is discharged to an exhaust system (not shown) through a bifurcated exhaust port 42, and the rotation of the crankshaft 33 obtained by combustion of the fuel in this combustion chamber 41 is output. It is configured as follows.

Each intake port 40 can communicate with the combustion chamber 41 by opening and closing two intake valves 43 (only one shown in FIG. 5), and each exhaust port 42 can communicate with two exhaust valves (only one shown in FIG. 5). It is possible to communicate with the combustion chamber 41 by opening and closing 44 (only one of which is shown in FIG. 1).

Each pair of intake valves 43 facing each cylinder is a rocker! 1!
It is pressed by the rotating ends of a pair of rocker arms (only one is shown in FIG. 5) 46, one end of which is pivotally supported by the valve 145, and can be opened against the elastic force of a pair of valve springs (not shown).

Similarly, each pair of exhaust valves 44 is pressed by a rotating end of a pair of rocker arms (only one shown in FIG. 5) 48 whose one end is pivotally supported on a rocker shaft 47, and a pair of valves (not shown) are pressed. It can be opened against the elastic force of the spring. In addition, reference numerals 51 and 52 in FIG. 5 indicate the first or second hydraulic piston (first
The same hydraulic piston as shown in Figure 1) is shown.

Here, each pair of intake valves 43 and exhaust valves 44 are shown in FIG.
Receives the valve opening force through the valve opening timing switching means elbow and lift amount switching means Ml similar to those explained in FIG. 10,
This is shown in Figures 3(a), (b), (e), and (d).

The valve opening timing switching means Ml and the lift amount switching means Ml are each supplied with pressurized oil from the main oil gear rally 39.

Here, the lift amount switching means Ml is a switching solenoid valve V
1, which receives an output current from a controller 50, which will be described later. Here, when on, high pressure oil is supplied to the oil passage 49 following the pressure chamber 28 (same as the pressure chamber in FIG. 11), and when off, the pressure chamber 28 can be opened to the drain side. For this reason, FIGS. 3(a) and (b).

As shown in (C) and (d), when on, the intake air,
Both exhaust valves 43 and 44 have high lift H2 and large operating angle θe2.
, θi2 can be ensured in high lift modes (C, D modes), and when off, both the intake and exhaust valves 43 and 44 have a low lift H1 and a small operating angle θe1. θ11 low lift mode (A.

B mode) can be secured. Note that the A mode can relatively improve low speed torque at low rotation and high load, and the B mode has a small overlap amount Δθ0, stable ignition, less blow-through, and can improve idling stability and m cost. In C mode, it is easy to improve high-speed torque at high rotation and low load, and in D mode, the overlap amount Δθ is relatively low at high rotation and high output.
0 becomes smaller, which not only improves output, but also suppresses intake air blow-through and improves fuel efficiency.

The intake and exhaust camshafts 31 and 32 are configured to receive the rotational force of the crankshaft 39 via valve opening timing switching means Ml similar to that shown in FIG.

Here, the elbows of the valve opening timing switching means are located at 31° and 32° of each camshaft.
It has a built-in twist mechanism that twists the timing gears 4i and 4e (corresponding to timing gear 4 in FIG. 9) (see FIG. 9), and the twisting hydraulic pressure is applied to each pressure chamber 13 via the switching solenoid valves v2 and v3. (See Figure 9).

The switching solenoid valves v2 and (3) are opened and operated by the output current of the controller 50. Among these, solenoid valve 2 is a duty valve, and each duty ratio output is 40% and 60 dollars.

The twisting hydraulic pressure based on 80% and 10 parts is guided to the pressure chamber 13 (see Fig. 9) through the oil passage 55, and the twisting mechanism operates in response to the twisting hydraulic pressure as shown in Figs. 3(a), (b), (C). )
, (d), Valve opening timing θIl, θI as shown in Fig. 4
2. θI3. The intake valve 43 can be opened using the θ mechanism 4.

The electromagnetic valve v3 is a switching valve, and transmits the twisting hydraulic pressure based on the OFF and ON outputs to the pressure chamber 13 (see FIG. 9) in the exhaust side twisting mechanism via the oil passage 56. In this case, the exhaust valve 44 can be driven at the valve opening timings θEl and θE2 as shown in FIGS. 3(a), (b), (c), (d), and FIG. 4(b).

The controller 50 includes a microcomputer 57 and a power supply 5.
8 power supply circuit 59. It is composed of a lift opening circuit 60 which outputs an output current to M2, a twist opening circuit 61 which outputs an output current to Mura and A2, and the like.

Here, the microcomputer 57 includes a torque sensor 62 that emits engine output torque information, a rotation sensor 63 that emits engine rotation speed information, an intake pressure sensor 64 that emits engine intake pressure information, and an idle switch 65 that emits engine idle information. etc., and drives and controls the valve opening timing switching means elbow and the lift amount switching means Ml in accordance with the valve timing lift control program shown in FIG.

Furthermore, a switching mode setting map shown in FIG. 6 is stored in the memory of the microcomputer 57. The switching mode range here is determined as follows.

First, the A-mode region and the B-mode region and the C-mode region and the D-mode region are distinguished by torque lines Tb and Tc at a boost setting (eg, intake pressure according to 1/2 load). Note that the torque lines Ta and Td are at full load.

The Pad line that separates the A mode region and the D mode region is determined as the locus of the intersection (indicated by an x in FIG. 6) where the outputs match each other at equal boost and equal rotational speeds. Similarly, the Pbc line that divides the B mode region and the C mode region is the intersection (6th
It is determined as a locus (indicated by an x mark in the figure).

The microcomputer 57 determines that there is a current operating range in each of these switching mode ranges, and controls the valve opening timing and valve lift to ensure each switching mode shown in FIG.

The operation of such a valve timing lift control device is controlled by the seventh
The explanation will be based on the valve timing lift control program shown in the figure.

The microcomputer 57 obtains operating information according to the current operating state by taking in data from each sensor.

Then, processing for determining the switching mode region is started.

Here, the current operating position PO is determined based on the engine speed and output torque. Then, compare the set boost pressure, which is the threshold value in the vertical direction of torque, with the current boost pressure to determine whether the current operating range is in the A, D mode region or in the B, C mode region. do. Next, the current engine speed is A based on the Pad line and the Pbc line, which are the threshold values for the engine speed.

Determine whether it is on the B mode area side or on the C or D mode area side. Then, the predetermined mode area is rewritten based on the switching mode area information to which the determined current driving area belongs.

After this, when step a3 is reached, a control signal is output to the lift drive circuit 60 and twist active circuit 61 in order to achieve a switching mode according to the current mode range.

As a result, each valve Vl of the valve opening timing switching means old and the lift amount switching means M2 is connected to the valve opening timing switching means old and the lift amount switching means M2 from each of the movement circuits 60 and 61.
V2. The required output current is supplied to V3, and A, B, C,
D mode (Figure 3 (a), (b), (C)
, (d)), the opening timing and lift amount of the intake valve 43 and exhaust valve 44 are activated.

As a result, output torque and fuel efficiency can be improved more efficiently with respect to the rotational speed and accelerator depression amount at that time.

In the above, the microcomputer had set four mode ranges in the divisions shown in FIG. 6, but instead of this, the lines Lab, Lb as shown in FIG.
c. A switching mode setting map divided by Lad may be set.

Here, first, the engine is operated in each of switching modes A, B, C, and D (see Figure 3), and each torque line Tb5T is calculated at equal boost with the intake pressure sequentially lowered from full load.
Find a, Tc, and Td. Then, it is determined as a locus of an intersection (indicated by an X in FIG. 8) where the outputs match each other at equal boost and equal rotational speed.

When controlling the valve timing and lift amount of the engine's intake and exhaust systems based on such a switching mode setting map, almost the same high efficiency can be obtained as when using the switching mode setting map described in the 6th article. In particular, in this case, the full-throttle output of the engine can be improved over almost the entire range of engine speed.

(Effect of the invention) At least four switching modes combined by switching the lift amount and valve opening timing can be secured, so the optimal switching mode can be selected for each operating position, and engine output and fuel efficiency can be improved more accurately. can be achieved.

[Brief Description of the Drawings] Fig. 1 is an overall schematic configuration diagram of a valve timing lift control device as an embodiment of the present invention, Fig. 2 is a block diagram of a control system including a controller used in the same device, and Fig. 3 (
a), (b), (c), and (d) are respectively different switching mode diagrams of the valve timing lift used in the same device, and FIGS. 4(a) and (b) are diagrams of each solenoid valve V2. The valve opening position characteristic diagram of the intake valve obtained based on V3 switching, Figure 5 is a sectional view of the main part of the valve train in the same device, and Figure 6 is the switching mode setting map used in the microcomputer of the same device. Characteristic diagram, 7th
The figure is a flowchart showing the flow of valve timing lift control performed by the microcomputer of the same device.
The figure is a characteristic diagram of another switching mode setting map that can be adopted in place of the switching mode setting map of Fig. 6, Fig. 9 is a sectional view of the old valve opening timing switching means, and Fig. 10 is the means of Fig. 9. Figure 11 is a characteristic diagram of the valve timing mode of the intake and exhaust valves driven by the lift amount switching means M.
FIG. 12 is a characteristic diagram of the lift amount and valve operating angle mode of the intake and exhaust valves operated by the means shown in FIG. 11. 30...Engine, 40...Intake port, 42...
・Exhaust port, 43... Intake valve, 44... Exhaust valve,
45.47...Rocker shaft, 46.48...Rocker arm, 5o...Con1-roller, 53,54...
Camshaft, 57...Microcomputer, 62...
Torque sensor, 63... Rotation sensor, 64... Intake pressure sensor.弗4 ■ Sai Zudokoro G Shape Prisoner Ensemble Niksha Riku [rFm] Fear q ■ Place (O cause? ■

Claims (1)

[Claims] Lift amount switching means that is attached to a valve train of the internal combustion engine and changes the lift amount of the intake valve; valve opening timing switching means that is installed to the valve train and switches the valve opening timing of the intake valve; and the internal combustion engine. an intake pressure sensor that emits intake pressure information, a load sensor that emits output information of the internal combustion engine, a rotation sensor that emits rotation speed information of the internal combustion engine; A valve timing lift control device comprising: a controller that selectively switches the lift amount switching means and the valve opening timing switching means so as to ensure at least four switching modes combined by switching the lift amount and valve opening timing.