JP2671593B2 - Engine throttle control - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement in an engine throttle control device.

(Prior Art) Many throttle opening / closing devices have been proposed that can arbitrarily change the characteristics between the operation amount of the access pedal and the actual throttle opening (see Japanese Patent Laid-Open No. 1-108156).

In such a device, for example, when the ratio of the throttle opening to the operation amount of the access pedal is reduced when the vehicle is traveling at low speed or when reversing, the output change of the engine becomes smooth,
Slow operation can be performed, and traction control or the like at the time of slip detection can be easily realized.

(Problems to be Solved by the Invention) By the way, in such a device, the throttle opening degree is changed only by running conditions such as slip and traffic congestion. Therefore, this device is directly applicable to a vehicle having a variable valve operating device. Driving becomes worse if it is performed.

For example, as shown in FIG. 4, in a variable valve device that includes a first cam that emphasizes fuel efficiency and second and third cams that emphasize power, and these cams can be switched, the first cam is shifted from the first cam to the third cam. 2
When the cam is switched to the cam, the torque increases. Therefore, if the same throttle opening is maintained, a torque step occurs before and after the switching.

Therefore, according to the present invention, when the cam is switched, the throttle opening is increased or decreased by a predetermined amount so that the same torque is maintained before and after the cam is switched with respect to the accelerator pedal operation amount when the cam is switched. In addition to preventing the deterioration of the actuator, the learning signal is used to control the actuator operation signal so that the actuator response speed matches the predetermined target speed. It is an object to provide a device for eliminating influence.

(Means for Solving the Problem) As shown in FIG. 1, the present invention is a throttle that can change a throttle opening degree according to an actuation signal (for example, actuation voltage) applied to an actuator regardless of the operation amount of an accelerator pedal. A variable valve operating device 62 including an opening / closing device 61, at least two cams having different valve lift characteristics, and a mechanism capable of switching these cams, a sensor 63 for detecting the access pedal operation amount α, and a sensor detection value thereof. Means 64 for selecting a cam according to the operating conditions determined based on
If the selected cam differs from the previously selected cam, the variable valve device is switched to the cam selected this time.
Means 65 for outputting a switching signal to 62 and the throttle opening
A sensor 66 for detecting TVO ₀ and a means 67 for calculating a target torque T ₀ for the currently used cam that will be obtained from the actual throttle opening TVO _{0 at} the time of switching the cam.
A means 68 for calculating the target throttle opening TVO ₁ for the cam to be used next based on this target torque T ₀ so that the same torque can be obtained before and after the cam switching, and the target throttle opening TVO ₁ and Difference from actual throttle opening detection value Δ
Means 69 for calculating TVO (= TVO ₁ −TVO ₀ ) and this difference ΔTVO
Means 70 for setting a basic signal (for example, basic voltage Vn) to the actuator, which is necessary to change the throttle opening only, a memory 71 for storing a learning correction amount K for this basic signal, and this memory 71. Means 72 for reading out the stored learning correction amount K, means 73 for correcting the basic signal by the read learning correction amount K, and determining an actuation signal to the actuator, and the determined actuation. Means 74 for outputting a signal to the actuator,
Means for measuring the actual response speed v of the actuator
75, a means 76 for comparing the response speed v with a predetermined target speed v _1, and the response speed v is stored in the memory 71 so as to match the target speed v ₁ based on the comparison result. A means 77 for updating the learning correction amount K is provided.

(Operation) For example, in the case where the variable valve operating device 62 is provided with two cams of a fuel-emphasis cam and a power-emphasis cam, and the switching signal output means 65 switches from a fuel-emphasis-emphasis cam to a power-emphasis cam, the calculation means In 67 and 68, according to the fuel economy-oriented cam, the target torque T ₀ that will be generated with respect to the throttle opening TVO _{0 at} that time is calculated, and from this torque T ₀ ,
The target throttle opening TVO ₁ required to generate the same torque T ₀ when the power-oriented cam is used is calculated.

Therefore, if the throttle opening is reduced by the opening difference ΔTVO between TVO ₀ and TVO ₁ when switching from the fuel efficiency-oriented cam to the power-oriented cam, the torque increase at the time of cam switching due to the difference in cam characteristics can be suppressed.

However, when the actuator is, for example, a motor, if the response speed has variations due to differences in the battery voltage or the operating temperature of the motor or deterioration over time, even if the same operating voltage (operating signal) is given, for example, the throttle valve is closed. May be significantly delayed.

In this case, the comparison means 76 compares the actual response speed v of the actuator with the target speed v _1, and if the speed is slower than the target speed v ₁ , the operating voltage (actuating signal) Vc to the actuator is Vc.
The learning correction amount K is updated by the updating means 77 so that This increase in the operating voltage increases the response speed of the actuator and drives the throttle valve at a desired speed.

On the contrary, when the actual response speed v of the actuator becomes faster than the target speed v ₁ , the learning correction amount K reduces the actuation voltage Vc to the actuator and delays the response speed.

(Embodiment) The variable valve apparatus shown in FIGS. 2 and 3 is a so-called end pivot type, and the configuration itself has already been proposed.

21 is a first cam focused on fuel economy, 22 and 23 are second and third cams focused on power, 24 is an intake valve (or an exhaust valve), 25 is a cam follower roller 26, and the roller 26 is a first cam.
A so-called roller rocker arm that contacts with 21 (a main rocker arm for a sub rocker arm described later), and 27 is a rocker shaft.

The main rocker arm 25 is
Sub rocker arms 28 and 29 are swingably supported,
The second cam 22 is in sliding contact with one sub rocker arm 28, and the third cam 23 is in sliding contact with the other sub rocker arm 29. However, sub rocker arm 29 (also for 28)
Has no part in contact with the valve 24, and as shown in FIG. 3, the cam is prevented from separating by the elastic force of the lost motion spring 31.

A columnar pin 32 is provided on the swinging portion of one sub rocker arm 28, and a pin 34 having the same axis and the same diameter as the pin 32 is also slidable in the rocker shaft direction on the main rocker arm 25. Provided, return spring 36
Is normally urged downward in FIG. 2 and is in the state shown in FIG. In this state, when the integrally formed cams 21 to 23 rotate, the main rocker arm 25 swings according to the first cam 21, and the intake valve 24 is opened and closed.

In this state, when hydraulic oil is guided to the hydraulic chamber 38 in which the pin 34 is accommodated via the oil passage 40, the two pins 34 and 32 are both pushed up in FIG. 2 against the return spring 36 in the base circle area of the cam. Then, the sub rocker arm 28 enters the main rocker arm 25 in a comb-stab state. In this comb stabbed state, both the main and sub rocker arms
Since the valves 28 and 25 operate integrally, the valve lift characteristics follow the second cam 22. That is, the valve lift characteristic is switched to power-oriented, and the generated torque is increased. Fifth
The figure shows the fully open performance of each of the cams 21 to 23.

The configuration of the other sub rocker arm 29 is the same as that of the one sub rocker arm 28.

The cams 21 to 23 have different profiles so as to satisfy the required valve lift characteristics at the time of partial load, low speed and high load, and high speed and high load, respectively (see FIG. 4). It is formed integrally.

The switching of the hydraulic pressure to the hydraulic chambers 38, 39 is performed by two solenoid valves 45, 46 shown in FIG. Each of the solenoid valves 45 and 46 is a normally closed type. When one of the solenoid valves 45 is opened by an ON signal from the control unit 51 as shown in the figure, the solenoid valve 45 and 46 are moved to a hydraulic chamber 38 for operating the second cam 22. Hydraulic oil is guided from the oil pump, and one valve 45 is closed and the other valve 46 is opened, whereby the hydraulic oil is guided to a hydraulic chamber 39 for operating the third cam 23.

In FIG. 6, a control unit 51 including a microcomputer detects a sensor (for example, a crank angle sensor) 52 that detects an engine speed Ne, a sensor 53 that detects an accelerator pedal operation amount α, and a throttle opening TVO ₀ . The signal from the sensor 54 is input, and in the control unit 51, the two solenoid valves 45 and 46 are turned on and off.
By outputting the F signal, the cams 21 to 23 are switched, the target throttle opening is obtained in accordance with the switching of the cams, and the target throttle opening is output to the servo drive circuit 55 at the target timing to perform the throttle operation.

The servo drive circuit 55 is connected to the throttle valve 57 according to the deviation between the two throttle openings so that the actual throttle opening detected by the throttle opening sensor 54 matches the target throttle opening output from the CPU. The servo motor (for example, DC motor) 56 is driven in forward and reverse directions.

Now, when considering when switching from the 1st cam to the 2nd cam, if the throttle opening does not change before and after the cam switching, the torque will increase significantly when the cam is switched as shown by the solid line in the middle of FIG. As a result, the vehicle body vibrates or a drivability is deteriorated due to this influence. To prevent such a torque step, the throttle opening should be reduced by a predetermined amount ΔTVO corresponding to the torque step, as shown by the solid line in the lower part of Fig. 16, and as shown by the broken line in the middle part of Fig. 16. It is possible to reduce the torque step difference before and after the cam switching.

However, if the response speed of the DC motor has variations due to differences in battery voltage, motor operating temperature, or due to deterioration over time, closing the throttle valve will be delayed even if the same operating voltage is applied, and the torque step will be effective. It may not be possible to suppress it. On the other hand, the actual response speed of the DC motor is measured, and if it is slower than the predetermined target speed, the operating voltage to the DC motor is increased to prevent variations due to battery voltage and deterioration over time. Throttle control can be performed without being affected.

In order to perform the throttle control including the voltage control to the DC motor, the flow charts of FIGS. 7 to 9 (FIG. 7 shows the cam switching control, and FIGS. 8 and 9 show the throttle control when switching the cam). Is executed every predetermined time.) Is created.

The operation of this example will be described with reference to these flowcharts. Depending on the operating conditions at that time, which of the three cams to use is set in advance as a map, and this map is shown in FIG. Show.

In order to refer to this map, in step 1, the accelerator pedal operation amount α and the engine speed Ne are read, and the optimum cam position for the operating conditions determined from these is determined.
Obtained from the map in Figure 10 (step 2).

In step 3, it is determined whether the cam position is the same as the cam position obtained last time, and if it is not the same, it is determined that the cam is to be switched, and a cam switching signal is output so that the cam position obtained this time is obtained (step 4).

Here, it is assumed that the switching from the first cam to the second cam has been performed corresponding to FIG. In this case, the throttle valve must be closed by a predetermined amount so that no torque step will occur before and after the cam switching.

Therefore, in step 13, the throttle opening at that time
The target torque T ₀ that may be generated in the first cam (the cam currently in use) is obtained from TVO ₀ and the engine speed Ne by referring to the torque map for the first cam, and then the torque T ₀ and From the engine speed Ne, refer to the torque map for the second cam to determine the target throttle opening TVO ₁ required to generate this same torque T ₀ when the second cam (the cam to be switched next) is used. Ask (step 14). For example, the target torque T ₀ is obtained from the map shown in FIG. 11, and the target throttle opening TVO ₁ is obtained from the map shown in FIG.

Therefore, when switching from the first cam to the second cam, TVO ₀
If the throttle opening is reduced by the difference ΔTVO (= TVO ₁ −TVO ₀ ) between the opening and the TVO ₁ , the torque changes as shown by the broken line in the middle of FIG. 16, and it is possible to suppress the torque increase during the cam switching.

On the other hand, in step 16, this opening difference ΔTVO and the allowable time t _TVO
Accordingly, the basic voltage (basic signal) Vn required to move the DC motor at the target speed v ₁ is obtained by referring to the map.
FIG. 13 shows the characteristics of the basic voltage Vn. As the difference ΔTVO increases, the basic voltage Vn increases as the opening difference ΔTVO increases without delay.

The allowable time t _TVO is the time allowed to drive the motor. For example, in FIG. 16,
By the time the cam switching is completed, the throttle valve is
You just have to make it smaller. In this case,
The time t _TVO is determined according to the engine speed Ne, and becomes shorter as the rotation speed becomes higher. Therefore, as shown in FIG. 13, the basic voltage Vn is made larger as the time t _TVO becomes shorter before switching to the second cam. The throttle valve is closed by ΔTVO.

Next, the operating voltage Vc applied to the motor is obtained from the basic voltage Vn and the learning correction coefficient K by referring to a map (step 17).

In this case, the learning correction coefficient K is a value updated according to the flowchart of FIG.

In step 22, the target speed v ₁ of the motor is obtained from the throttle opening difference ΔTVO during cam switching and the allowable time t _TVO by referring to the map in FIG. 15, while in steps 23 and 24 this opening difference ΔTVO is calculated. The actual response speed v of the motor is calculated by measuring the time taken for the actual movement of the motor (motor response time) t'and dividing ΔTVO by this response time t '.

These actual response speed v and target speed v ₁ are compared, and v <
If v ₁ , the learning correction coefficient K is increased by a predetermined value (constant value) ΔK. Conversely, if v> v ₁ , K is changed to a value smaller by ΔK (steps 25 to 27). When the engine is started, K = 1.

Based on the learning correction coefficient K obtained in this way, the basic voltage
The map for correcting Vn and determining the operating voltage Vc is the 14th map.
It is the characteristic shown in the figure.

The basic voltage Vn is a value when there is no variation or deterioration with time due to the battery voltage, and only in that case, the motor is driven at the target speed v ₁ .

However, if the motor becomes difficult to operate due to a decrease in the operating temperature of the motor, for example, even if the basic voltage Vn is applied, the motor can only be driven at a speed lower than the target speed. As indicated by the chain line, a situation occurs in which the operation cannot be completed within the allowable time t _TVO .

In such a case, in this example, the learning correction coefficient K is 1
When a larger value is stored and the operating voltage Vc is made larger than the basic voltage Vn, the response speed of the motor is increased according to the characteristic shown in FIG.

On the contrary, when the actual response speed v is faster than the target speed v ₁ due to the operating temperature of the motor becoming high, the response speed of the motor is changed by the correction coefficient K smaller than 1. Is delayed.

That is, by making the response speed of the motor always match the target speed v ₁ by the learning control, it is not necessary to be affected by the difference in the battery voltage or the operating temperature of the motor or the change over time.

For the target speed v ₁ of the motor, the throttle opening difference Δ
Since it is calculated according to TVO and the allowable time t _TVO , the optimum target value can be given even if ΔTVO and the engine speed Ne greatly differ. Be further accordance with the motor temperature and the temperature of the cooling temperature, etc., also depending on the temperature, such as target velocity v ₁ temperature or cooling water temperature, it is possible to determine the target speed v _1.

Here, the description has been given of the switching from the first cam to the second cam, but the same applies to the switching from the second cam to the third cam and vice versa.

Incidentally, in relation to FIG. 1, step 2 is cam selection means 64, steps 3 and 4 are switching signal output means 65, step 13
Is target torque calculation means 67, step 14 is target throttle opening calculation means 68, step 15 is throttle opening difference calculation means 69, step 16 is basic signal setting means, step 17 is learning correction amount reading means 72 and actuation signal determination Means 73, step 18 is operation signal output means 74, steps 23, 24 are response speed measuring means 75, step 25 is comparing means 76, steps 26, 27
Fulfills the function of the learning correction amount updating means 77.

FIG. 17 and FIG. 18 show another embodiment, in which an arbitrary number of simple average values K _AVE and weighted average values Ks for the learning correction coefficient are used to determine the operating voltage Vc to the motor. Is.

For example, in FIG. 17, in step 31, all the j learning correction coefficients K _{1 to} Kj and their average value K _AVE are read. In this case, K _{1 to} Kj are j obtained by the previous cam switching.
This is a correction coefficient newly obtained as the number of the subscript increases. At the time of starting, the value of all j is 1.

In step 33, the average value _KAVE of the learning correction coefficient and the basic voltage Vn
The operating voltage Vc is obtained from the above, and the response speed v when the motor is driven by this Vc is measured (step 35).

In step 36, the current learning correction coefficient Kj ₊₁ is obtained by comparing this speed v with the target speed v ₁ , and this value is used to newly obtain the following equation K _AVE = (jK _AVE + Kj ₊₁ −K ₁ ) / j The simple average value K _AVE of the learning correction coefficient is calculated (step 37).

Rewrite the index added to the learning correction coefficient K in step 38 to a value decremented by 1 and replace them with the new average value K.
Store in memory together with _AVE (step 39).

According to this example, the reliability of controlling the motor operating voltage is higher than that of the previous examples.

Similarly, according to the weighted average value Ks in FIG. 18, j
Weighting coefficient Si for ₊₁ learning correction coefficients K _{1 to} Kj ₊₁
By setting (i is a number from 1 to j + 1) as shown in FIG. 19 and making the most of the latest data, the reliability of motor operating voltage control can be further enhanced.

Although the DC motor is used as the actuator for driving the throttle valve in the embodiment, a step motor may be used. Further, the actuator may be of a diaphragm type that responds to hydraulic pressure or the like, and in this case, the signal is pressure.

(Effect of the Invention) According to the present invention, when the cam is switched, the throttle operation is performed so as not to cause the torque step due to the difference in the cam characteristics, and the response speed of the actuator that drives the throttle valve matches the predetermined target speed. As described above, since the operation signal to the actuator is controlled, it is possible to suppress the torque fluctuation at the time of switching the cam and maintain the drivability satisfactorily, and even if there is a variation or a temporal change due to the battery voltage or the like. , And can be operated at the desired actuator response speed without being affected by this.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to the claims of the present invention, FIG. 2 is a plan view of a variable valve operating device of an embodiment, FIG. 3 is a sectional view taken along line XX of FIG. 2, and FIGS. FIG. 6 is a characteristic diagram of valve lift and full-open torque of this device, FIG. 6 is a control system diagram of the above embodiment, FIGS. 7 to 9 are flow charts for explaining control operation of this embodiment, and FIGS. FIG. 15 is a map characteristic diagram of the cam position, the target torque for the first cam, the target torque for the second cam, the basic voltage, the operating voltage, and the target speed, and FIG. 16 is also for explaining the action at the time of switching the cam. It is a waveform diagram. FIG. 17 and FIG. 18 are flow charts for explaining the control operation of another embodiment, respectively, and FIG. 19 is a characteristic diagram of the weighting coefficient used in FIG. 21: First cam, 22: Second cam, 23: Third cam, 25
…… Main rocker arm, 28,29… Sub rocker arm, 32-35 …… Pin, 38,39… Hydraulic chamber, 45,46… Solenoid valve, 51 …… Control unit, 52 ……
Crank angle sensor (engine speed sensor), 53 …… accelerator pedal operation amount sensor, 54 …… throttle opening sensor, 55 …… servo drive circuit, 56 …… servo motor (DC motor), 57 …… throttle valve, 61 ... Throttle opening / closing device, 62 ... Variable valve operating device, 63 ... Accelerator pedal operation amount sensor, 64 ... Cam selection means, 65 ... Switching signal output means, 66 ... Throttle opening sensor, 67 ... Target torque calculation means, 68 ... Target throttle opening calculation means, 69 ...
Throttle opening difference calculation means, 70 ... Basic signal setting means,
71 …… Memory, 72 …… Learning correction amount reading means, 73 ……
Operation signal determining means, 74 ... Operation signal outputting means, 75 ... Response speed measuring means, 76 ... Comparison means, 77 ... Learning correction amount updating means.

Claims (1)

(57) [Claims] 1. A throttle opening / closing device capable of changing a throttle opening degree in accordance with an actuation signal given to an actuator regardless of an operation amount of an accelerator pedal, at least two cams having different valve lift characteristics, and switching between these cams. A variable valve operating device including a mechanism, a sensor for detecting the operation amount of the access pedal, a means for selecting a cam according to an operating condition determined based on the sensor detection value, and a cam selected last time by this selection In this case, the means for outputting a switching signal to the variable valve device so that the cam selected this time can be switched, the sensor for detecting the throttle opening, and the actual throttle opening at that time when switching the cam. The means to calculate the target torque for the cam currently in use and the same torque before and after switching the cam will be obtained. As described above, means for calculating the target throttle opening degree for the cam to be used next based on this target torque, means for calculating the difference between this target throttle opening degree and the actual throttle opening degree detection value, and the throttle amount corresponding to this difference Means for setting a basic signal to the actuator, which is necessary for changing the opening, a memory for storing a learning correction amount for this basic signal, and a means for reading the learning correction amount stored in this memory, Means for correcting the basic signal by the read learning correction amount to determine an actuation signal to the actuator, means for outputting the determined actuation signal to the actuator, and an actual response of the actuator. Means to measure speed,
A means for comparing the response speed with a predetermined target speed and a means for updating the learning correction amount stored in the memory so that the response speed matches the target speed based on the comparison result are provided. An engine throttle control device characterized by the above.