JP6375527B2 - Control device for variable displacement oil pump - Google Patents

Description

  The present invention relates to a control device for a variable displacement oil pump.

  Patent Document 1 describes the discharge flow rate per rotation of a variable displacement oil pump that supplies hydraulic oil to a continuously variable transmission for the purpose of improving fuel efficiency by suppressing excessive discharge flow rate. Accordingly, a technique for providing a required flow rate according to the hydraulic pressure required by the continuously variable transmission is disclosed.

JP 2005-114103 A

However, in the above-described prior art, when the driver greatly depresses the accelerator pedal during traveling at a constant speed, there is a problem that the hydraulic response required by the response delay of the oil pump cannot be ensured. On the other hand, although the hydraulic response can be ensured by always maintaining the maximum discharge flow rate, the original fuel saving effect is hindered.
An object of the present invention is to provide a control device for a variable displacement oil pump that can achieve both the required hydraulic response and the fuel saving.

  In the present invention, when the accelerator depression speed is equal to or higher than the speed threshold value, a command to set the discharge flow rate to the maximum flow rate is output to the variable displacement oil pump, and the accelerator operation amount is determined within the determination time after outputting the command. When the operation amount threshold value is reached, a command to set the discharge flow rate to the maximum flow rate is continuously output, while when the accelerator operation amount does not reach the operation amount threshold value within the determination time, a command to set the discharge flow rate to the required flow rate is issued. Output.

  In the present invention, when the accelerator is stepped on or increased and the initial stepping speed is high, a command to set the discharge flow rate to the maximum flow rate is output. Therefore, in a scene where high hydraulic response is required, the required hydraulic response Can be secured. On the other hand, if the accelerator operation amount does not reach the operation amount threshold within the judgment time after outputting the command to set the output flow rate to the maximum flow rate, high hydraulic response is required to switch the discharge flow rate from the maximum flow rate to the required flow rate. In situations where it is not possible, it is possible to suppress the discharge of excessive hydraulic oil and to suppress the influence on the fuel saving effect. As a result, it is possible to achieve both required oil pressure response and fuel saving.

It is a block diagram of the powertrain control system of Example 1. 5 is a flowchart showing a flow of a pump flow rate control process of the transmission controller 14. 3 is a time chart showing an operation for ensuring hydraulic response in the first embodiment. 3 is a time chart showing the operation of maintaining the fuel saving effect in Example 1.

[Example 1]
[System configuration]
FIG. 1 is a configuration diagram of a powertrain control system according to the first embodiment.
The powertrain control system of the first embodiment includes an engine 1, a belt type continuously variable transmission (hereinafter referred to as CVT) 2, a torque converter 3, a lock-up clutch 4, a variable displacement oil pump (hereinafter referred to as oil pump) 5, and a forward / reverse travel. Switching mechanism 6, accelerator pedal 7, accelerator opening sensor (accelerator operation amount detecting means) 8, engine controller 9, throttle valve 10, throttle actuator 11, throttle opening sensor 12, engine speed sensor 13, transmission controller (capacity) Control means) 14, a transmission input rotation sensor 15, a transmission output rotation sensor 16, a temperature sensor 17, a drive shaft 18, and a drive wheel 19.

The intake air amount of the engine 1 is controlled by the throttle valve 10. The throttle valve 10 is a butterfly valve and is driven by a throttle actuator 11. The throttle actuator 11 is a stepping motor, for example. The throttle actuator 11 operates based on a command signal from the engine controller 9, and drives the throttle valve 10 to an opening degree corresponding to the command signal.
The engine controller 9 includes a signal from the engine speed sensor 13 that detects the engine speed Ne, a signal from the accelerator position sensor 8 that detects the opening APO of the accelerator pedal 7 (the amount of operation of the accelerator pedal), and the engine load. A signal or the like from the throttle opening sensor 12 for detecting the throttle opening TVO corresponding to is input. The engine controller 9 outputs a command signal for performing ignition timing control and throttle opening degree control of the engine 1 based on each signal.

The torque converter 3 is connected to the engine output shaft 1a. The lockup clutch 4 directly connects the engine output shaft 1a and the CVT2. The forward / reverse switching mechanism 6 is provided between the engine output shaft 1a and the CVT 2, and transmits the rotation direction of the engine output shaft 1a to the CVT 2. The forward / reverse switching mechanism 6 is constituted by a planetary gear mechanism. The output of CVT 2 is transmitted to the drive shaft 18 connected to the drive wheel 19.
The CVT 2 has a primary pulley 2a, a secondary pulley 2b, and a belt 2c as main components, and the speed ratio is variable by changing the width of the pulley grooves of both pulleys 2a and 2b. The CVT 2 changes the width of the pulley grooves of the pulleys 2a and 2b to a width corresponding to the command signal based on the command signal from the transmission controller 14. The change of the groove width is performed by hydraulic control to a primary pulley cylinder chamber and a secondary pulley cylinder chamber (not shown).

The transmission controller 14 includes a signal from the transmission input rotation sensor 15 that detects the input rotation speed Nt of the CVT2, a signal from the transmission output rotation sensor 16 that detects the output rotation speed No of the CVT2, and the oil pan of the CVT2 In addition to the signal from the temperature sensor 17 for detecting the oil temperature T _CVTF , the engine speed Ne, the accelerator pedal opening APO, the throttle opening TVO, and the like are input. The transmission controller 14 outputs a command signal for executing the transmission ratio control of the CVT 2 based on each signal.
The oil pump 5 is driven by the engine 1 and supplies hydraulic oil to the CVT 2. The oil pump 5 is a variable displacement vane pump, for example. The variable displacement vane pump changes the displacement of each pump chamber by changing the amount of eccentricity of the cam ring with respect to the rotor, thereby making the discharge flow rate per rotation variable. The oil pump 5 changes the discharge flow rate to a discharge flow rate corresponding to the command signal based on the command signal from the transmission controller 14. The discharge pressure of the oil pump 5 is supplied to the CVT 2 as a line pressure. In addition, what adjusted the discharge pressure of the oil pump 5 with the pressure regulation valve (pressure regulator valve) is good also as a line pressure.

The transmission controller 14 outputs a command signal for performing pump flow rate control for changing the discharge flow rate of the oil pump 5 based on signals from each sensor or the like. The transmission controller 14 calculates the required hydraulic pressure of CVT2 (≈ target value of the line pressure) based on the driving state of the vehicle, and sets the discharge flow rate of the oil pump 5 required to obtain the required hydraulic pressure as the required flow rate. A command signal with a required flow rate is generated. A value obtained by multiplying the required flow rate by a certain safety factor may be used. The required oil pressure is set to a higher value as the accelerator opening APO (or the throttle opening TVO) is higher, the gear ratio of CVT2 is larger, or the oil temperature T _CVTF is higher. Further, the required hydraulic pressure is set to a higher value during shifting than during non-shifting.

[Pump flow control processing]
In the first embodiment, the following pump flow rate control process is performed in the transmission controller 14 with the aim of ensuring both required hydraulic response and fuel saving. The transmission controller 14 includes an accelerator opening speed detector (accelerator operating speed detector) 14a and a response delay time detector (response delay time detector) 14b as means for performing the pump flow rate control process. When the accelerator pedal 7 is depressed, the accelerator opening speed detection unit 14a calculates the accelerator opening speed (accelerator depression speed) ΔAPO based on the current accelerator opening and the accelerator opening before a predetermined time (for example, several tens of milliseconds). Calculate. The response delay time detection unit 14b detects the response delay time by observing the actual hydraulic pressure response time of the oil pump 5. Here, the response delay time of the oil pump 5 is the time until the actual discharge flow rate starts to change according to the change of the command signal.

FIG. 2 is a flowchart showing the flow of the pump flow rate control process of the transmission controller 14, and each step will be described below.
In step S1, a command to set the discharge flow rate to the required flow rate is output to the oil pump 5. In addition, about calculation of required flow volume, it is assumed that it is repeatedly performed with a predetermined calculation period in parallel with this process.
In step S2, the accelerator opening speed? APO is equal to or speed threshold? APO _{- th} or more. If YES, the process proceeds to step S3. If NO, the process returns to step S1.

In step S3, a command to set the discharge flow rate to the maximum flow rate is output to the oil pump 5.
In step S4, it is determined whether or not the accelerator opening APO is _{equal to} or _larger than the opening threshold (operation amount threshold) _{APO_th} even once within the determination time after outputting the command to set the discharge flow rate to the maximum flow in step S3. . If YES, the process proceeds to step S5. If NO, the process returns to step S1. Here, the determination time is set to be equal to or shorter than the response delay time of the oil pump 5 and is longer as the response delay time is longer. Further, the opening threshold value _{APO_th} is set to a higher value as the response delay time of the oil pump 5 is longer.

In step S5, the output of the command for setting the discharge flow rate to the maximum flow rate is continued to the oil pump 5.
In step S6, it is determined whether or not a predetermined time has elapsed since the command for setting the discharge flow rate to the maximum flow rate in step S3. If YES, the process proceeds to step S7. If NO, the process returns to step S5. The fixed time is a time longer than the response delay time of the oil pump 5 in which the actual hydraulic response of the CVT 2 matches the command.
In step S7, a command for setting the discharge flow rate to the required flow rate is output to the oil pump 5.

Next, the operation will be described.
FIG. 3 is a time chart showing the hydraulic pressure response ensuring operation in the first embodiment. FIG. 3A is Comparative Example 1, and FIG. In the first comparative example, similarly to the conventional variable displacement oil pump, the discharge flow rate is always controlled to the required flow rate corresponding to the required hydraulic pressure calculated from the vehicle operating state (accelerator opening, gear ratio, oil temperature, etc.). It is an example.
In Comparative Example 1, as with the conventional variable displacement oil pump, the discharge flow rate is always controlled to the required flow rate corresponding to the required hydraulic pressure calculated from the vehicle operating state (accelerator opening, gear ratio, oil temperature, etc.). doing. As a result, the excessive discharge flow rate is suppressed to reduce the work amount of the variable displacement oil pump, thereby improving the fuel consumption. Here, as shown in FIG. 3, when the driver depresses the accelerator pedal greatly from a constant speed and tries to obtain strong acceleration, first, the required hydraulic pressure required by the CVT is calculated from the signals of the sensors. Therefore, although the value of the calculated discharge flow rate also increases, the response of the variable displacement oil pump is delayed by several tens of milliseconds with respect to the command. This delay is mainly due to the time required to increase the discharge flow rate per rotation (for example, in the case of a variable displacement vane pump, the eccentric amount of the cam ring with respect to the rotor is increased).

  The hydraulic pressure inside the CVT (CVT hydraulic pressure) does not increase unless the discharge flow rate of hydraulic oil discharged from the oil pump increases. As a result, the hydraulic pressure response is worse than when a fixed displacement oil pump is used. In Comparative Example 1, as shown in Fig. 3 (a), the actual hydraulic pressure of the CVT is required because the delay of the actual discharge flow rate (actual flow rate) with respect to the command (command flow rate) of the discharge flow rate of the oil pump (OP) is large. By falling below the hydraulic pressure, belt slip due to insufficient clamp pressure or engine torque reduction for avoiding belt slip occurs, and the acceleration required by the driver cannot be obtained, resulting in adverse effects such as deteriorated drivability.

In contrast, in Example 1, at the moment it is detected that the accelerator opening speed? APO is speed threshold? APO _{- th} or more, the maximum flow rate and the discharge flow rate regardless of the required flow (S1 → S2 → S3). In other words, if there is a possibility that the accelerator pedal will be depressed greatly, that is, if the required hydraulic pressure of CVT2 calculated from the accelerator opening APO may increase, do not wait for the required hydraulic pressure and required flow rate to be calculated. A command signal for setting the discharge flow rate to the maximum flow rate is output to the oil pump 5. Thereby, since the response delay time of the actual discharge flow rate with respect to the accelerator depression timing can be shortened, the required hydraulic response can be ensured in a scene where a high hydraulic response is required. As shown in FIG. 3B, in Example 1, the actual flow rate increases to the maximum flow rate earlier than in Comparative Example 1, so the actual hydraulic pressure of CVT2 does not fall below the required hydraulic pressure, and the belt There are no problems such as slipping or engine torque down.

In the first embodiment, after outputting a command signal for setting the discharge flow rate to the maximum flow rate, it is determined whether or not the maximum capacity should be maintained by comparing the accelerator opening APO and the opening threshold _{APO_th} during the determination time (S3). → S4). Then, if APO _{exceeds APO_th} even once during the judgment time, the command signal for maximum flow rate is continuously output, and then the command signal for required flow rate is switched when a certain time has passed (S4 → S5 → S6 → S7). The fixed time is the time when the actual hydraulic pressure response of CVT2 matches the command, and the actual hydraulic pressure matches the required hydraulic pressure calculated according to the operating state. There is no risk of falling below the required oil pressure.

FIG. 4 is a time chart showing the operation of maintaining the fuel saving effect in the first embodiment. 4 (a) shows the comparative example 2, and FIG. 4 (b) shows the first embodiment. Comparative Example 2 is the same as Example 1 in that the discharge flow rate is set to the maximum flow rate based on the comparison result between the accelerator opening speed and the speed threshold value, but the maximum flow rate based on the comparison between the accelerator opening and the opening threshold value after the determination time. This is an example in which the maximum flow rate is maintained without performing the maintenance determination.
FIG. 4 shows a situation where a high hydraulic response is not required because the accelerator opening speed ΔAPO is lower than in FIG. 3 and the final accelerator opening APO is also small. However, since the final accelerator opening APO is unknown at the initial stage of accelerator depression, high hydraulic response may be required. Therefore, in order to ensure the required hydraulic response, the speed threshold value ΔAPO_th compared with the accelerator opening speed ΔAPO must be _reduced to some extent, and the discharge flow rate is set to the maximum flow rate even in the accelerator operation as shown in FIG. A command signal is output.

When the maximum flow rate is maintained as shown in Fig. 4 (a), the hydraulic fluid is discharged by the difference between the actual flow rate and the required flow rate, which is higher than the originally required flow rate. This means that the amount of pump work that can be done has not been reduced. In other words, in order to ensure the hydraulic response, simply by setting the discharge flow rate to the maximum flow rate, the fuel saving effect that is the original purpose is hindered.
Therefore, in the first embodiment, as shown in FIG. 4 (b), after outputting a command signal for setting the discharge flow rate to the maximum flow rate, if the APO _does not _{exceed APO_th} during the determination time, the maximum flow rate is set. The command signal to be canceled is canceled and the command signal is switched to the required flow rate (S4 → S1). That is, when high hydraulic pressure response is not required, by immediately switching the discharge flow rate from the maximum flow rate to the required flow rate, excessive hydraulic oil discharge can be suppressed and the influence on the fuel saving effect can be suppressed.

  At this time, the determination time for determining whether or not the maximum flow rate needs to be maintained based on the accelerator opening APO is set to be equal to or shorter than the response delay time of the oil pump 5. By setting the determination time to be equal to or shorter than the response delay time, the command signal for setting the maximum flow rate can be canceled before the discharge flow rate starts rising when high hydraulic response is unnecessary. Thereby, the influence on the fuel saving effect can be made almost zero.

Here, there are individual differences in the response delay of the variable displacement oil pump. Therefore, to make sure that the maximum flow rate is maintained based on the accelerator opening APO within the response delay time, regardless of individual differences, to make the impact on the fuel economy effect zero, shorten the judgment time. There is a need to. However, if the determination time is shortened, the opening degree threshold _{APO_th} must be set to a low value. This is because, when the opening threshold _{APO_th} is set to a high value, the determination time is short, and therefore the accelerator opening APO does not reach the opening threshold _{APO_th} in most situations, and the determination becomes impossible. And, when the opening threshold _{APO_th} is set to a low value, there is a concern that fuel consumption may deteriorate due to an increase in misjudgment that a high hydraulic response is required even in a scene where high hydraulic response is not required. .

On the other hand, in the first embodiment, the response delay time detection unit 14b detects the response delay time of the oil pump 5, and changes the determination time and the opening threshold value _{APO_th} according to the detected response delay time. Specifically, the longer the response delay time, the longer the determination time, and the longer the response delay time, the higher the opening threshold _{APO_th} . By providing a means for detecting the response delay time, the response delay of the oil pump 5 can be detected accurately, so that the maximum response based on the accelerator opening APO can be ensured within the response delay time regardless of individual differences in the oil pump 5. The necessity of maintaining the flow rate can be determined. Further, the longer the response delay time, the longer the determination time and the higher the opening degree threshold _{APO_th} , so that erroneous determination can be suppressed. As a result, the rebound to the fuel saving effect can be reduced.

As described above, Example 1 has the following effects.
(1) A CVT 2 provided on the power transmission path between the engine 1 and the drive wheels 19, a variable displacement oil pump 5 driven by the engine 1 and supplying hydraulic oil to the CVT 2, and a vehicle operating state The transmission controller 14 that calculates a required flow rate based on the output and outputs a command for the discharge flow rate to the variable displacement oil pump 5, an accelerator opening sensor 8 that detects the accelerator opening APO, and an accelerator opening speed ΔAPO and a accelerator opening speed detecting section 14a for detecting a transmission controller 14, when the accelerator opening speed? APO is speed threshold? APO _{- th} or more, and the maximum flow rate and the discharge flow rate to the variable displacement pump 5 When the accelerator opening APO reaches the opening threshold _{APO_th} within the determination time after the output of the instruction, the command for continuously setting the discharge flow rate to the maximum flow rate is output, while the determination time Access When the opening APO has not reached the opening threshold APO _{- th} outputs a command that requires a flow rate of discharge flow rate.
Therefore, it is possible to achieve both the required hydraulic response and the fuel saving.

(2) The transmission controller 14 sets the determination time to be equal to or shorter than the response delay time of the variable displacement oil pump 5.
Therefore, the influence on the fuel saving effect can be made almost zero.

(3) A response delay time detection unit 14b that detects the response delay time of the variable displacement oil pump 5 is provided, and the transmission controller 14 changes the judgment time and the opening threshold _{APO_th} according to the detected response delay time. To do.
Therefore, it is possible to suppress erroneous determination that the scene requires high hydraulic response, and to reduce the rebound to the fuel saving effect.

(Other examples)
As mentioned above, although the form for implementing this invention was demonstrated based on the Example, the concrete structure of this invention is not limited to an Example, The design change of the range which does not deviate from the summary of invention And the like are included in the present invention.
For example, in the first embodiment, an example in which a vane pump is used as a variable displacement oil pump has been described. However, a piston pump or a gear pump may be used as long as the discharge flow rate per rotation can be changed.

1 engine
2 CVT (continuously variable transmission)
1a Engine output shaft
2a Primary pulley
2b Secondary pulley
2c belt
3 Torque converter
4 Lock-up clutch
5 Oil pump
5 Variable displacement oil pump
6 Forward / reverse switching mechanism
7 Accelerator pedal
8 Accelerator opening sensor (accelerator operation amount detection means)
9 Engine controller
10 Throttle valve
11 Throttle actuator
12 Throttle opening sensor
13 Engine speed sensor
14 Transmission controller (capacity control means)
14a Accelerator opening speed detector (accelerator operating speed detector)
14b Response delay time detector (response delay time detection means)
15 Transmission input rotation sensor
16 Transmission output rotation sensor
17 Temperature sensor
18 Drive shaft
19 Drive wheels

Claims (2)

A continuously variable transmission provided on a power transmission path between the engine and the drive wheels;
A variable displacement oil pump that is driven by the engine and supplies hydraulic oil to the continuously variable transmission;
A capacity control means for calculating a required flow rate based on a driving state of the vehicle and outputting a command to set the discharge flow rate to the required flow rate to the variable displacement oil pump;
An accelerator operation amount detection means for detecting an operation amount of the driver's accelerator pedal;
An accelerator operation speed detecting means for detecting a depression speed of the driver's accelerator pedal;
With
When the accelerator depression speed is equal to or greater than a speed threshold, the capacity control means outputs a command to set the discharge flow rate to the maximum flow rate to the variable displacement oil pump, and within a determination time after outputting the command. When the accelerator operation amount reaches the operation amount threshold value, the command for continuously setting the discharge flow rate to the maximum flow rate is continuously output, while when the accelerator operation amount does not reach the operation amount threshold value within the determination time, A control device for a variable displacement oil pump, which outputs a command for setting a discharge flow rate to the required flow rate. In the control apparatus of the variable displacement oil pump according to claim 1,
The variable capacity oil pump control device, wherein the displacement control means sets the determination time to be equal to or shorter than a response delay time of the variable displacement oil pump.

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