JPH02271014A - Valve action controller for engine - Google Patents

Abstract

PURPOSE:To prevent the generation of a great torque at the time of changeover of an valve action angle by changing the valve action angle property being set for normal time, so that it may also be optimum at transition period. CONSTITUTION:A setting means 25 for valve action angle at normal time sets valve action angle optimum at normal time according to the signal from an engine revolution sensor 24, and a setting means 26 for valve action angle at transition period sets valve action angle optimum at transition period according to the same signal. A judging means 27 at operation receives the signal from the sensor 24 and judges whether it is transition period or normal time, and a selecting means 28 selects the valve action angle at normal time in the case where it is judged as normal time and selects the valve action angle at transition period in the case here it is judged as transition period, respectively. Moreover, an output means 29 outputs the control quantity in accordance with the decided valve action angle, and the hydraulic pressure being controlled according to the control quantity is introduced into a hydraulic actuator 22 by a valve means 23, and a valve action angle varying mechanism 21 makes the valve action angle variable according to the hydraulic pressure. Hereby, the operability at transition period also becomes excellent.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a device for controlling the valve operating angle of an engine using hydraulic pressure, and particularly to control during transient times.

(Prior Art) Devices have been known that vary the valve operating angle of an intake valve or an exhaust valve depending on the operating state for the purpose of improving fuel efficiency, output performance, etc. of an engine (for example, 19
MTZ (Motorteehnisc) published in May 1986.
(see Z.Eitschrift).

To explain this with reference to Fig. 10, this is an example of a so-called direct drive type overhead cam that directly drives the valve from above the valve without a rocker arm, and two valves with the same function. , I B 7ter 3
A, 3 B, plate member 4A.

Conical three-dimensional cams 5A and 5B whose diameter increases toward the rear left are brought into contact via the cam 4B.

The camshaft 6 on which these cams 5 A and 5 B are integrally formed has a camshaft 7 at its right front end.
A seven cutuator 11 is configured to move the seat 6 in the axial direction. In detail, the outer peripheral surface of the camshaft end,
Splines 6A and 12A that engage with the inner peripheral surface of a circular sill 12 provided to cover this are cut in the axial direction, and the camshaft 6 slides in the axial direction through this spline connection. Can move freely. An external gear 14 is fixed to the outer periphery of the sill 12, and is rotated in synchronization with the crankshaft by a toothed belt (not shown).

On the other hand, a spring (not shown) is provided that biases the camshaft 6 toward the 7-cut unit 11, and a hydraulic chamber 13 is defined between the cam shirt F end and the sill 12. , an internal oil passage and an oil hole 15 communicate with a hydraulic pressure supply passage from an oil pump. In addition,
The camshaft 6 is formed hollow to reduce weight.
The oil in the hydraulic chamber 13 will not leak through this hollow hole 6B, and 16 is a discharge port for releasing the hydraulic pressure introduced into the hydraulic chamber 13, and 17 is a spline part that seals the oil leaking. It is a member.

Here, there is an oil hole 15 in the hydraulic chamber 13. When hydraulic pressure from the oil pump is introduced through the internal oil passage, the hydraulic pressure resists the spring force and moves the camshaft 6 to the cutout 11 (see figure 7).
Drive to the side away from (rear left in the figure).

In this case, the diameter of the three-dimensional cam increases toward the rear left, so when the camshaft 6 moves to the rear left, the sliding contact position between the plates 4A, 4B and the three-dimensional cam 5A, 5B changes. The valve operating angle becomes smaller accordingly. In other words, the valve operating angle can be freely changed depending on the oil pressure. Note that 18 and 19 are stoppers that determine the initial position of the camshaft in the axial direction when no hydraulic pressure is applied.

(Problem to be solved by the invention) By using such a variable valve operating angle mechanism, the valve operating angle can be adjusted according to the operating conditions (for example, dividing the rotation speed into three regions, and adjusting the valve operating angle to small and medium speeds in the low rotation range). Inside the dedicated area.

When controlling the oil pressure so that it is large in the high rotation range), the oil pressure to the hydraulic chamber 13 is set accordingly (high pressure in the low rotation range, medium pressure in the middle and soft rotation range, and low pressure in the high rotation range). , the oil pressure is switched according to the actual engine speed. Specifically, when a spool-type pressure control valve is installed in the hydraulic passage to the hydraulic chamber 13, the amount of spool displacement corresponds to the hydraulic pressure introduced into the hydraulic chamber 13, so the signal from the rotation speed sensor is input. A control signal is output from the control device to this control valve.

In this case, when the operating point exceeds the boundary of the three rotational speed regions described above, a control signal is output to switch the oil pressure, but the control signal is output and the valve operating angle is actually changed. The time difference until switching occurs as a response delay, and this response delay is relatively larger during rapid acceleration than during slow acceleration. For this reason, during sudden acceleration, the torque temporarily decreases as the valve operating angle is changed, causing a feeling of sluggish driving, and a smooth acceleration sensation f cannot be obtained.

The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a device that prevents large torque changes from occurring when switching the valve operating angle.

(Means for Solving the Problems) As shown in FIG. a mechanism 21 that is equipped with a hydraulic actuator for controlling the valve and makes the valve operating angle variable according to the oil pressure, and a hydraulic actuator 22 that is interposed in a hydraulic passage leading to the hydraulic actuator 22 and that changes the valve operating angle according to the amount of W to be controlled.
a valve means 23 for controlling the hydraulic pressure introduced into the engine; a sensor 24 for detecting the engine speed (N e);
means 25 for setting an optimum valve operating angle in a steady state in response to a signal from the sensor 4; means 26 for setting an optimum valve operating angle in a transient state in response to the same signal; Means 2 for determining whether it is a normal time or a steady state
7, means 28 for selecting the valve operating angle in the steady state when it is determined that the state is in the steady state, and the valve operating angle in the transient state when it is determined that the state is in the transient state; The valve means 23 controls the control amount according to the selected valve operating angle.
A means 29 for outputting the information is provided.

(Function) For example, during sudden acceleration, the response delay of the hydraulic system becomes relatively large with respect to changes in engine speed, so switching of the valve operating angle is delayed, causing a temporary drop in acceleration.

On the other hand, according to the present invention, the optimum valve operating angle is set for both the steady state and the transient state, so that the valve operating angle for the transient state is selected during sudden acceleration. Here, according to the valve operating angle at the time of sudden acceleration, the switching of the valve operating angle is made faster, so the response delay of the hydraulic system is absorbed, and the drop in the acceleration described above is avoided.

On the other hand, during sudden deceleration, switching of the valve operating angle is delayed, which improves drivability during gear changes.

(Example) The mechanism for making the valve operating angle variable is the same as shown in Figure @10, and this 8! A control system shown in FIG. 2 is set up to control the hydraulic actuator 11 of the system.

In the figure, numeral 41 is a spool-type pressure control valve installed in a hydraulic passage connecting the hydraulic chamber 13 and an oil pump (not shown), and the hydraulic pressure introduced into the hydraulic chamber 13 changes according to the amount of spool displacement. .

42 is a sensor that outputs an output according to the engine rotation speed (N e), 43 is a sensor that outputs an output according to the engine load (Load), and signals from these are input to the control unit 44. The control unit 44 is composed of, for example, a microcomputer, and includes tlfJ3
A control signal is output to the control valve 41 according to the operation shown in the figure. The control unit 44 has the functions of the means 25 to 29 in correspondence with FIG. In addition,
The above-mentioned Load includes, for example, the intake air amount and intake negative pressure.

FIG. 3 is a flowchart adapted for acceleration. N in Sl
e and Load are read, and it is determined in S2 whether acceleration is being performed. For example, by comparing the amount of change in rotational speed per certain time (dNe/dt) with 0, dNe/dt≦O
If so, it is determined that it is a steady state (deceleration is not considered here), and the process proceeds to S3, where the optimum valve operating angle θ0 for a steady state is read out according to Ne and Load at that time.

When the 00 map is shown in the plfJ4 diagram, the rotation speed range is roughly divided into three areas: a small valve operating angle in the low rotation range, a medium valve operating angle in the medium rotation range, and a large valve operating angle in the high rotation range. It is set. Therefore, the rotation speed that provides the boundary of the rotation speed region is the rotation speed that switches the valve operating angle, and in the figure, when the operating fish crosses these switching rotation speeds Ncl and Nc2, a control signal is sent to change the spool displacement amount. Output.

If it is determined in S2 that the vehicle is accelerating since dNe/dL>0, the process proceeds to S5, where it is determined whether the acceleration is rapid or slow. For example, dNe/dt is compared with a predetermined value Ca>, and if dNe/dt>α, it is determined that there is a sudden acceleration and the process proceeds to S6. Here again, the valve operating angle corresponding to Ne and Load at that time is read from the map, but its contents are different from the map described above. If the map in this case, that is, the map of the valve operating angle θ1 during sudden acceleration, is shown in Figure 5, the switching rotation speed N c lH * N c2H is lower by a certain value (ΔN) than in the case of Figure 4. is set to . This means that during sudden acceleration, the signal for switching the valve operating angle is output earlier than during steady state. Note that if it is determined in S5 that the acceleration is slow, the process proceeds to S3 since it is handled the same as in a steady state.

S4. In S7, the valve operating angle (θ0
．． θ1) is transferred to a memory named θ, and the valve operating angle transferred to this memory is converted into a control amount (spool displacement amount) to the control valve 41 in S8.

Here, the operation of this example will be explained with reference to FIGS. 6 and 7.

In Figure 6, the valve operating angle (θ0) during steady state is small.

This is a diagram showing overlapping torque curves for medium and large torque curves (the solid line corresponds to when θ0 is small, the broken line corresponds to when θ0 is medium, and the -1α nod line corresponds to when θ0 is large). 2αA shown
If more rapid acceleration was performed, as shown by the thick line,
It is desirable to change each torque curve so that the maximum torque can be obtained for the rotational speed at that time.

However, during sudden acceleration, the response delay of the hydraulic system becomes relatively large with respect to changes in engine speed, so the Ncl shown in FIG.

If the control signal is switched by Ne2, the acceleration will temporarily drop as traced by the thick line in the lower part of FIG.

On the other hand, according to this example, the switching rotation speed is Ncl,
Since the speed increases by ΔN from Ne2 to N c lH * N c2H, the torque characteristic traced by the thick line in Fig. 6 is obtained, and correspondingly, the acceleration is traced by the largest thin line in the lower part of Fig. 7. Therefore, a temporary drop in acceleration due to switching can be avoided.

In other words, in consideration of the fact that the response delay of the hydraulic system increases during sudden acceleration, the response delay is absorbed by switching the control signal earlier by the response delay. As a result, even during rapid acceleration, the charging efficiency for each rotational speed is approximately the maximum, smooth acceleration is achieved, and no shift shock occurs.

Next, FIG. 8 shows another embodiment. In this example, instead of setting the decrease in the switching rotation speed (ΔN above) to a constant value, the rotational acceleration (dNe/dt) and the oil temperature ( It is designed to be set variably depending on the TO), for example f5
Figure 9 shows the decrease in switching rotation speed (ΔN+) with respect to dNe/dL and TO. Since ΔN1 is configured as a variable value, the map of the valve operating angle in steady state is corrected using this ΔN1 in S14, and the valve operating angle is read from the corrected map.

This other example takes into consideration that the lower the oil temperature and the larger dNe/dt, the greater the response delay of the hydraulic system.According to this example, even during rapid acceleration at low oil temperature, The valve operating angle can be set optimally, improving drivability.

Although the embodiment has been described in terms of acceleration, it can also be applied during deceleration. For example, if Load is higher than a predetermined value and Ne is decreasing (during high load deceleration), the gear may be lowered by one step to achieve high speed rotation, so in this case, the valve operating angle may be lowered. Lower the switching speed to delay switching.

Finally, the splines 6A and 12A shown in Fig. 10 do not need to be parallel to the camshaft 6; if they are installed diagonally, the timing of valve opening and closing will depend not only on the valve operating angle but also on the oil pressure. will change.

It goes without saying that the present invention can be applied to this case as well.

(Effects of the invention) In this invention, while setting the optimum negative valve operation characteristic for steady state conditions, this characteristic is also changed to be optimal during transient conditions, resulting in improved operability during transient conditions. .

[Brief explanation of drawings]

FIG. 1 is a diagram corresponding to claims of the present invention, and FIG. 2 is a system diagram of a control system according to an embodiment of the present invention. FIG. 3 is a flow chart for explaining the control operation of this embodiment, and FIGS.
The figure is a diagram showing the contents of the map used in this control operation, Figures 6 and 7 are characteristic diagrams for explaining the action of this embodiment, and Figure 8 is a diagram showing the control operation of another embodiment. FIG. 9 is a diagram showing the contents of a map used in this control operation, and FIG. 10 is a partially cutaway perspective view of a conventional example. I A, I B... Valve, 5 A, 5 B... Three-dimensional cam, 6... Camshaft, 11... Actuator, 13... Hydraulic chamber, 21... Valve operating angle variable? fi structure, 22...-hydraulic 7 Kuchiyu engineering unit, 23... valve means,
24... Engine rotation speed sensor, 25... Steady state valve operating angle setting means, 26... Transient valve operating angle setting means,
27... Operation determination means, 28... Selection means, 29
... Output means, 41 ... Pressure control valve (valve means), 4
2... Rotation speed sensor, 43... Engine load sensor, 44... Control unit. NC1NC2 Ne Fig. 5 e Fig. 6 Engine rotation speed Fig. 7 Acceleration @Dark Fig. 8

Claims (1)

[Claims] It is equipped with a three-dimensional cam formed in a conical shape in the axial direction of the camshaft, and a hydraulic actuator for moving the camshaft on which this cam is formed in the ring direction, and a mechanism that changes the valve operating angle according to the oil pressure. , a valve means interposed in a hydraulic passage introduced into the hydraulic actuator to control the hydraulic pressure introduced into the hydraulic actuator according to a control amount; a sensor for detecting the engine rotation speed; means for setting an optimum valve operating angle during a transient period; and means for setting an optimum valve operating angle during a transient period in response to the same signal;
means for receiving a signal from the sensor to determine whether the state is in a transient state or a steady state; An engine characterized in that it is provided with means for selecting each of the valve operating angles during the transient period when the determination is made, and means for outputting a control amount according to the selected valve operating angle to the valve means. Valve actuator.