JP7337452B2 - vehicle controller - Google Patents

Description

The present invention relates to a control device for controlling a vehicle in which an automatic transmission is interposed between an internal combustion engine and drive wheels.

2. Description of the Related Art A belt-type CVT (see, for example, Patent Document 1 below) is known as a type of drive system transmission interposed between an internal combustion engine mounted on a vehicle as a power source and driving wheels of the vehicle. A belt-type CVT consists of a drive pulley supported by the drive shaft on the internal combustion engine side and a driven pulley supported by the driven shaft on the drive wheel side with a belt wound around them. The engine torque input to is transmitted to the driven shaft and further to the driving wheels of the vehicle.

When idling the internal combustion engine, such as when the vehicle is stopped, the deviation between the actual engine speed and the target idle speed is calculated, and the opening of the throttle valve is operated to reduce the deviation. , adjusts the amount of intake air charged into the cylinder and the amount of injection, and implements feedback control to increase or decrease the output of the internal combustion engine (see, for example, Patent Document 2 below).

JP 2019-135383 A JP 2015-121193 A

When the clutch interposed between the output shaft of the internal combustion engine and the driving wheels of the vehicle is switched on and off, the driver typically shifts the shift lever (or selector lever) from the N range, which is the non-driving range, to the driving range. , or when the driver switches from the D or R range to the N range, the mechanical load on the internal combustion engine greatly increases or decreases.

During feedback control of the engine speed, the output of the internal combustion engine is corrected according to the deviation between the actually measured speed and the target speed. However, the effect of the correction is so great that the engine speed deviates from the target speed, causing hunting, which is vibration in the vertical direction. That is, when the disengaged clutch is engaged, the output of the internal combustion engine is increased to compensate for the falling engine speed, resulting in an overshoot in which the engine speed exceeds the target speed. By reducing the output of the internal combustion engine in an attempt to suppress this, an undershoot occurs in which the engine speed falls below the target speed. Similarly, repeated undershoots and overshoots of the engine speed may occur when the engaged clutch is disengaged.

Such hunting of the engine speed becomes conspicuous in recent vehicles in which the friction loss of the internal combustion engine has been thoroughly reduced.

SUMMARY OF THE INVENTION An intended object of the present invention is to suppress or alleviate hunting that occurs during feedback control of the engine speed.

In order to solve the above-described problems, the present invention calculates the deviation between the actually measured engine speed and the target idle engine speed, and reduces the deviation so that the actually measured engine speed converges to the target idle engine speed. During feedback control that adjusts the opening of the throttle valve and the amount of fuel injection , when switching the clutch interposed between the output shaft of the internal combustion engine and the drive wheels of the vehicle from the disengaged state to the engaged state, or When the clutch is switched from the engaged state to the disengaged state, if the absolute value of the amount of change in the rotational speed of the turbine of the torque converter per unit time exceeds a predetermined threshold value, feedback control of the rotational speed of the internal combustion engine is temporarily performed. is interrupted to maintain the throttle valve opening and the fuel injection amount at the immediately preceding values regardless of the difference between the measured revolution speed and the target idle revolution speed.

According to the present invention, hunting that occurs during feedback control of the rotational speed of an internal combustion engine mounted on a vehicle can be suppressed or alleviated.

1 is a diagram showing a schematic configuration of a vehicle internal combustion engine and a control device according to an embodiment of the present invention; FIG. The figure which shows the structure of the drive system of the vehicle in the same embodiment. FIG. 4 is a flow diagram showing an example of the procedure of processing executed by the control device according to the embodiment according to the program; FIG. 4 is a timing chart illustrating how control is performed by the control device of the embodiment;

One embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an outline of a vehicle internal combustion engine 100 according to this embodiment. The internal combustion engine 100 supplies driving force for running to the axle 103 and the drive wheels through the drive system of the vehicle. The internal combustion engine 100 is, for example, a spark ignition four-stroke gasoline engine, and includes a plurality of cylinders 1 (one of which is shown in FIG. 1). An injector 11 for injecting fuel toward the intake port is provided upstream of the intake valve of each cylinder 1 and in the vicinity of the intake port connected to each cylinder 1 . A spark plug 12 is attached to the ceiling of the combustion chamber of each cylinder 1 . The spark plug 12 receives an induced voltage generated by an ignition coil and induces spark discharge between a center electrode and a ground electrode. The ignition coil is integrally built into the coil case together with the igniter, which is a semiconductor switching element.

An intake passage 3 for supplying intake air takes in air from the outside and guides it to the intake port of each cylinder 1 . An air cleaner 31, an electronic throttle valve 32, a surge tank 33, and an intake manifold 34 are arranged in this order on the intake passage 3 from upstream.

An exhaust passage 4 for discharging exhaust guides the exhaust generated by burning fuel in the cylinder 1 from the exhaust port of each cylinder 1 to the outside. An exhaust manifold 42 and a three-way catalyst 41 for purifying exhaust gas are arranged on the exhaust passage 4 .

The exhaust gas recirculation device 2 realizes so-called high-pressure loop EGR, and is an external EGR device that communicates the upstream side of the catalyst 41 in the exhaust passage 4 and the downstream side of the throttle valve 32 in the intake passage 3. A passage 21 , an EGR cooler 22 provided on the EGR passage 21 , and an EGR valve 23 that opens and closes the EGR passage 21 to control the flow rate of EGR gas flowing through the EGR passage 21 are elements. The inlet of the EGR passage 21 is connected to the exhaust manifold 42 in the exhaust passage 4 or a predetermined location downstream thereof. The outlet of the EGR passage 21 is connected to a predetermined location downstream of the throttle valve 32 in the intake passage 3, specifically to a surge tank 33. As shown in FIG.

FIG. 2 shows the transmission of the driving system provided in the vehicle of this embodiment. This transmission comprises a torque converter 7 and an automatic transmission 8,9. In this embodiment, a forward/reverse switching device 8 including a planetary gear mechanism and a belt-type CVT (Continuously Variable Transmission) 9 are employed as components of the automatic transmissions 8 and 9 .

The engine torque output by the internal combustion engine 100 is input from the crankshaft, which is the output shaft of the internal combustion engine 100, to the pump impeller 71 on the input side of the torque converter 7, and is transmitted to the turbine runner 72 on the output side. The rotation of the turbine runner 72 is transmitted to the drive shaft 94 of the CVT 9 via the forward/reverse switching device 8 and rotates the driven shaft 95 through the speed change in the CVT 9 . Rotation of the driven shaft 95 is transmitted to the output gear 101 . The output gear 101 meshes with a ring gear 102 of a differential, and rotates an axle (drive shaft) 103 and drive wheels attached to the axle 103 through the differential.

The torque converter 7 has a lockup mechanism. The lockup mechanism includes a lockup clutch 73 that engages the input side and the output side of the torque converter 7 so that they cannot rotate relative to each other, and a lockup that controls hydraulic pressure (hydraulic pressure) for switching the lockup clutch 73. An up solenoid valve (not shown) is used as an element.

In a vehicle equipped with the CVT 9, the torque converter 7 is almost always locked up when the vehicle speed is higher than a certain level. When the vehicle speed becomes lower than that, the lockup of the torque converter 7 is released. During lockup, the speed ratio, which is the ratio of the output-side rotation speed of the torque converter 7 to the input-side rotation speed, is 1. On the contrary, when the lockup is not performed, the speed ratio of the torque converter 7 becomes smaller or larger than 1 depending on the drive state.

The forward/reverse switching device 8 has a sun gear 81 in communication with the turbine runner 72 and a ring gear 82 in communication with the drive shaft 94 . Between the planetary carrier 83 supporting the planetary gear 831 and the transmission case, a forward brake 84, which is a hydraulic clutch capable of switching between connecting and disconnecting, is interposed. Between the planetary carrier 83 and the sun gear 81 (or the output side of the torque converter 7), a reverse clutch 85, which is a hydraulic clutch capable of switching between connecting and disconnecting, is interposed.

In the D range of the driving ranges, the forward brake 84 is engaged and the reverse clutch 85 is disengaged. As a result, the rotation of the output shaft of the torque converter 7 is reversed, decelerated, and transmitted to the drive shaft 94, so that the vehicle travels forward. Conversely, in the R range, the reverse clutch 85 is engaged and the forward brake 84 is disengaged. As a result, the sun gear 81 and the planetary carrier 83 rotate integrally, and the output shaft of the torque converter 7 and the drive shaft 94 are directly connected to allow reverse travel.

In the N range of the non-running ranges, both the forward brake 84 and the reverse clutch 85 are disengaged. In the P range, the axle 103 is mechanically locked so that it does not move.

The CVT 9 is known in this field, and includes a drive pulley 91 non-rotatably supported on a drive shaft 94 and a driven pulley 92 non-rotatably supported on a driven shaft 95 parallel to the drive shaft 94. and a belt 93 wound around a drive pulley 91 and a driven pulley 92 .

The drive pulley 91 has a fixed sheave 911 fixed to the drive shaft 94 and a movable sheave 912 arranged to face the fixed sheave 911 with the belt 93 interposed therebetween. The movable sheave 912 is supported on the drive shaft 94 via a roller spline so as to be displaceable in its axial direction and non-rotatable relative to it. A cylinder fixed to the drive shaft 94 is provided behind the movable sheave 912 on the side opposite to the fixed sheave 911 , and a hydraulic pressure chamber 913 is formed between the cylinder and the movable sheave 912 .

The driven pulley 91 has a fixed sheave 921 fixed to the driven shaft 95 and a movable sheave 922 arranged to face the fixed sheave 921 with the belt 93 interposed therebetween. The movable sheave 922 is supported on the driven shaft 95 through a roller spline so as to be displaceable in its axial direction and non-rotatable relative to it. A cylinder fixed to the driven shaft 95 is provided behind the movable sheave 922 on the side opposite to the fixed sheave 921 , and a fluid pressure chamber 923 is formed between the cylinder and the movable sheave 922 .

In the belt-type CVT 9, the working hydraulic pressure (hydraulic pressure) supplied to each of the hydraulic chambers 913 and 923 of the drive pulley 91 and the driven pulley 92 is controlled, and the width of the groove sandwiching the belt 93 in each of the pulleys 91 and 92 is changed. As a result, the pulley ratio between the drive pulley 91 and the driven pulley 92, in other words, the gear ratio realized by the CVT 9 is continuously and steplessly changed. When the pulley ratio is reduced, the hydraulic pressure supplied to the hydraulic pressure chamber 913 of the driving pulley 91 is relatively increased, and the hydraulic pressure supplied to the hydraulic pressure chamber 923 of the driven pulley 92 is relatively decreased. be done. As a result, the movable sheave 912 of the driving pulley 91 moves toward the stationary sheave 911, and the gap between the stationary sheave 911 and the movable sheave 912, that is, the width of the groove, becomes smaller. Accordingly, the winding diameter of the belt 93 around the driving pulley 91 increases, and the gap between the fixed sheave 921 and the movable sheave 922 of the driven pulley 92, that is, the groove width increases. As a result, the pulley ratio between the drive pulley 91 and the driven pulley 92 is reduced.

Conversely, when the pulley ratio is increased, the hydraulic pressure supplied to the hydraulic pressure chamber 913 of the driving pulley 91 is relatively reduced, and the hydraulic pressure supplied to the hydraulic pressure chamber 923 of the driven pulley 92 is relatively low. is increased to As a result, the thrust force of the driven pulley 92 against the belt 93 becomes greater than the thrust force of the drive pulley 91 against the belt 93, the gap between the fixed sheave 921 and the movable sheave 922 of the driven pulley 92 becomes smaller, and the fixed sheave 911 and the movable sheave 911 become smaller. The distance from 912 is increased. As a result, the pulley ratio between the drive pulley 91 and the driven pulley 92 is increased.

A hydraulic pump (or an oil pump, not shown) that discharges hydraulic fluid to be supplied to the hydraulic servos 913 and 923 of the CVT 9 operates by receiving engine torque from the crankshaft of the internal combustion engine 100. It is mechanical (non-electric). Generally, the hydraulic fluid for CVT 9 is common to the fluid used for torque converter 7 .

The thrust of the drive pulley 91 and the driven pulley 92 must be large enough to prevent slippage between the pulleys 91 and 92 and the belt 93 . Therefore, the hydraulic pressure to be supplied to the hydraulic pressure chambers 913 and 923 of the pulleys 91 and 92 is increased or decreased so as to obtain a thrust corresponding to the magnitude of the engine torque input to the drive shaft 94 . The hydraulic pressure to be supplied to the hydraulic chambers 913 and 923 is adjusted through operation of a transmission control valve (not shown), ie, a solenoid valve which is a flow control valve.

An ECU (Electronic Control Unit) 0, which is a vehicle control device according to the present embodiment, is a microcomputer system having a processor, a memory, an input interface, an output interface, and the like. The ECU 0 may be formed by connecting a plurality of ECUs or controllers so as to be able to communicate with each other via electric communication lines such as CAN (Controller Area Network).

The input interface of the ECU 0 receives a vehicle speed signal a output from a vehicle speed sensor that detects the actual vehicle speed, a crank angle signal output from a crank angle sensor that detects the rotation angle of the crankshaft of the internal combustion engine 100 and the engine speed. b, an accelerator opening signal c output from a sensor that detects the amount of depression of the accelerator pedal or the opening of the throttle valve 32 as the accelerator opening (so to speak, the required engine torque or engine load factor); surge in the intake passage 3; An intake air temperature/pressure signal d output from a temperature/pressure sensor that detects the intake air temperature and pressure in the tank 33 or the intake manifold 34, and a cooling water temperature signal output from a water temperature sensor that detects the cooling water temperature of the internal combustion engine 100. e, a shift position signal f output from a shift position switch that detects the position of the shift lever (or selector lever) operated by the driver, a switch that detects that the driver is stepping on the brake pedal, A brake depression amount signal g output from a sensor that detects the depression amount of the brake pedal or from a sensor that detects the master cylinder pressure, which is the pressure of the brake fluid discharged from the master cylinder, and the rotation speed of the turbine 72 of the torque converter 7 are detected. A turbine rotation speed signal h, etc., output from a rotation sensor is input.

From the output interface of the ECU 0, an ignition signal i for the igniter of the spark plug 12, a fuel injection signal j for the injector 11, an opening operation signal k for the throttle valve 32, and an opening operation signal for the EGR valve 23. A signal l, an opening operation signal t for the lockup solenoid valve for switching the connection/disconnection of the lockup clutch 73, an opening operation signal u for the solenoid valve for switching the connection/disconnection of the forward brake 84 or the reverse clutch 85, A control signal v etc. is output to a shift control valve for operating the hydraulic pressure servos 913 and 923 of the CVT 9 .

The processor of the ECU 0 interprets and executes programs stored in memory in advance, calculates operating parameters, and controls the internal combustion engine 100 and drive systems 7 , 8 , and 9 . The ECU 0 acquires various types of information a, b, c, d, e, f, g, and h necessary for operation control of the internal combustion engine 100 via an input interface, and determines the amount of intake air (or new required fuel injection amount (necessary to realize the target air-fuel ratio set at or near the theoretical air-fuel ratio), fuel injection timing (including the number of fuel injections for one combustion), fuel injection pressure, ignition timing (including the number of ignitions for one combustion), required EGR rate (or EGR gas amount), whether or not to lock up the torque converter 7, connection/disconnection state of the forward/reverse switching device 8, CVT 9 It determines various operating parameters such as the transmission gear ratio. The ECU 0 applies various control signals i, j, k, l, t, u, and v corresponding to the operating parameters through the output interface.

Thus, as shown in FIG. 3, when the ECU 0 of the present embodiment performs feedback control for converging the rotation speed of the internal combustion engine 100 to the target rotation speed (step S1), the crankshaft of the internal combustion engine 100 and the When the forward/reverse switching device 8, which is a clutch interposed between the axle 103 and the forward/rearward travel switching device 8, is switched from the disconnected state to the connected state, or when the forward/rearward travel switching device 8 is switched from the connected state to the disconnected state (step S2), the torque converter 7 If the absolute value of the amount of change in the rotation speed of the turbine 72 per unit time exceeds a predetermined threshold value (step S3), the feedback control of the rotation speed of the internal combustion engine is temporarily interrupted (step S4).

The feedback control referred to in step S1 is typically feedback control in which the driver does not depress the accelerator pedal or depresses the brake pedal and the engine speed converges to a predetermined target idling speed. During the feedback control, the deviation between the measured engine speed and the target idle speed is calculated, and the opening of the throttle valve 32 is operated so as to reduce the deviation. By adjusting the injection amount, the output of the internal combustion engine 100 is increased or decreased. At this time, the torque converter 7 is not locked up.

The switching of the forward/reverse switching device 8 in step S2 is typically performed by the driver operating the shift lever to switch the shift position from the D range or R range to the N range, or by switching the shift position from the N range to the D range. To switch to range or R range. As already described, in the D range or R range, which are driving ranges, the forward/reverse switching device 8 connects between the output shaft of the torque converter 7 on the turbine 72 side and the input shaft of the CVT 9 on the drive pulley 91 side. In the N range, which is the non-running range, the forward/reverse switching device 8 disconnects the output shaft of the torque converter 7 on the turbine 72 side and the input shaft of the CVT 9 on the drive pulley 91 side.

However, the switching of the forward/reverse switching device 8 in step S2 may be automatically executed by the ECU 0 regardless of the driver's operation. For example, in modern vehicles, so-called neutral control (neutral idle control) is performed in order to improve fuel efficiency. Neutral control means that when the driver depresses the brake pedal to stop the vehicle while selecting the D range, the output shaft of the torque converter 7 on the turbine 72 side and the drive pulley 91 side of the CVT 9 in the forward/reverse switching device 8 and the input shaft, and then automatically connect them in the forward/reverse switching device 8 when the driver takes his/her foot off the brake pedal.

At step S3, the absolute value of the amount of change in the rotation speed of the turbine 72 exceeding the threshold value means that the mechanical load on the internal combustion engine 100, which is the power source, greatly increases or decreases. This causes hunting of the engine speed controlled by feedback. A drop in the engine speed leads to engine stall, and an excessive increase in the engine speed leads to an increase in fuel consumption, so neither of these is preferable.

In step S4, the ECU 0 maintains the opening of the throttle valve 32 at the opening just before that regardless of the difference between the actually measured engine speed and the target speed. As a result, the amount of intake air charged into the cylinder 1 and the amount of fuel injected from the injector 11 are also maintained at the previous amounts regardless of the deviation between the actual engine speed and the target speed. It will be.

FIG. 4 exemplifies the pattern of control performed by the ECU 0 of the present embodiment. If steps S2 to S4 are not executed and the feedback control of the engine speed is continued without temporary interruption even when switching the forward/reverse switching device 8, as indicated by the one-dot chain line in FIG. , engine speed hunting may occur. However, if the feedback control of the engine speed is temporarily interrupted when switching the forward/reverse switching device 8, the hunting of the engine speed can be suppressed to a small level as indicated by the solid line in FIG. can be done.

The present invention is not limited to the embodiments detailed above. For example, in the above embodiment, the opening of the electronic throttle valve 32 is manipulated during feedback control of the engine speed to increase or decrease the amount of intake air and the amount of fuel injected into the cylinder 1, thereby increasing the output of the internal combustion engine 100. I was trying to adjust. However, if an idle speed control valve is installed as an intake throttle valve together with the throttle valve 32 in the intake passage 3 of the internal combustion engine, instead of operating the opening of the throttle valve 32, or By manipulating the opening degree of the idle speed control valve as well as operating the engine speed, the amount of intake air charged into the cylinder 1 and the amount of fuel injection can be increased or decreased, and the output of the internal combustion engine 100 can be adjusted. As is well known, the idle speed control valve is a flow control valve that opens and closes a bypass connecting the upstream side and the downstream side of the throttle valve 32 in the intake passage 3 . In this case, in step S4, the opening of the idle speed control valve is maintained at the previous value regardless of the difference between the actual engine speed and the target speed.

Moreover, the form of the automatic transmission mounted on the vehicle is not limited to the belt-type CVT 9 .

In addition, the specific configuration of each part, the procedure of processing, and the like can be modified in various ways without departing from the scope of the present invention.

INDUSTRIAL APPLICABILITY The present invention can be applied to control of an internal combustion engine and drive system mounted on a vehicle.

0... Control unit (ECU)
DESCRIPTION OF SYMBOLS 100... Internal combustion engine 1... Cylinder 11... Injector 3... Intake passage 32... Throttle valve 7... Torque converter 72... Turbine 8... Clutch (Forward-reverse switching device)
84 Forward brake 9 Continuously variable transmission (belt type CVT)
b... crank angle signal f... shift position signal j... control signal for injector k... control signal for throttle valve u... control signal for forward/reverse switching device

Claims (1)

Calculate the deviation between the measured engine speed and the target idle speed, and adjust the opening of the throttle valve and the amount of fuel injection so as to reduce the deviation so that the measured speed converges to the target idle speed. When the feedback control is performed , when switching the clutch interposed between the output shaft of the internal combustion engine and the drive wheels of the vehicle from the disengaged state to the connected state, or when switching the clutch from the connected state to the disengaged state, If the absolute value of the amount of change in the rotational speed of the turbine of the torque converter per unit time exceeds a predetermined threshold, the feedback control of the rotational speed of the internal combustion engine is temporarily interrupted, and the measured rotational speed and the target idle rotational speed are detected. A control device for a vehicle that maintains the throttle valve opening and the fuel injection amount at the immediately preceding amounts regardless of the deviation from

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