JP4508995B2 - Powertrain control device for vehicle - Google Patents

Description

  The present invention relates to a powertrain control device for a vehicle provided with an electric supercharger.

  2. Description of the Related Art Conventionally, a vehicle engine in which a supercharger is provided to increase intake efficiency and increase engine output has been adopted. Turbochargers include turbochargers that use engine exhaust, and mechanical turbochargers that use part of the engine's power as the driving force. Recently, however, motors have been used to drive compressors. An engine using an electric supercharger has been proposed (for example, Patent Document 1).

In such an engine, intake air supercharged by rotation of a compressor driven by an electric motor is supplied to the engine.
JP 2000-45812 A

However, when this electric supercharger operates continuously for a long time, the temperature of each part such as windings, stators, and bearings in the electric motor rises above the allowable temperature, and the electric motor and compressor are damaged, There is a concern that a problem may occur in which the battery is over-discharged to reduce the battery life.
In addition, in order to solve such a problem, a temperature sensor is provided in each part of the electric supercharger to detect an excessive temperature rise, or a supply current to the electric supercharger is detected to detect battery overdischarge. Although it is necessary to stop the electric supercharger when it is determined that there is a possibility, a temperature sensor and a current sensor must be newly provided for this purpose, which causes a problem that costs increase.

  This invention is made | formed in view of such a subject, The place made into the objective is to be able to prevent the excessive temperature rise of an electric supercharger, without adding a new sensor etc. Another object of the present invention is to provide a vehicle powertrain control device.

In order to achieve the above object, a vehicle powertrain control device according to the present invention is provided in an intake passage of an engine mounted on a vehicle and is driven by an electric motor to supercharge intake air of the engine. An intake air control means for controlling the intake air amount of the engine, a transmission for changing the output rotation of the engine and transmitting it to the wheels of the vehicle, and Based on the steady running determination means for determining that the vehicle is in a steady running state, a supercharging region where supercharging is performed by the electric supercharger and a natural charging region where supercharging is not performed are determined based on the operating state of the engine, Control means for operating the electric supercharger when the engine is in the supercharge region to perform supercharging while stopping the electric supercharger when the engine is in the natural air supply region; Preparation Wherein, when the operating state of the engine is the electric supercharger be in the supercharging zone is activated, when the steady running determining means determines that said a steady running state, the engine Until the operating state shifts to the natural air supply range, the transmission gear ratio of the transmission is increased to increase the engine speed, and the intake air is maintained so that the engine output before the change of the transmission ratio is maintained. Control means is controlled (claim 1).

According to the vehicle powertrain control device configured as described above, when the engine is in a predetermined supercharging region, supercharging is performed by operating the electric supercharger, and the operating state of the engine is the supercharging. If it is determined that the vehicle is in a steady running state when the electric supercharger is operating , the transmission gear ratio is increased to increase the engine speed, and the transmission gear ratio is changed. The intake air control means is controlled to maintain the previous engine output. As a result, when the engine operating state changes toward the natural supercharging region without reducing the engine output, and the engine operating state shifts to the natural air charging region, the increase in the gear ratio and the intake air control means Stop control. The electric supercharger is stopped when the operating state of the engine has shifted to the natural air supply region.

In the vehicular powertrain control apparatus configured as described above, the control means immediately increases the speed ratio and controls the intake air control means when the engine operating state enters the natural air supply range. It stops (claim 2).
According to the vehicle powertrain control device configured as described above, the increase in the gear ratio is stopped as soon as the engine operating state enters the natural air supply region. Compared with the case where the gear ratio is increased, the increase in the engine speed associated with the increase in the gear ratio is reduced.

Further, in these vehicle powertrain control devices, the transmission is a continuously variable transmission (claim 3).
According to the vehicular powertrain control device configured as described above, when increasing the speed ratio of the transmission to increase the engine speed, the engine speed is continuously increased by continuously increasing the speed ratio. To rise.

According to the vehicle powertrain control device of the present invention, when the vehicle is in a steady running state when supercharging by the electric supercharger is performed, due to an increase in engine speed due to an increase in the transmission gear ratio, Since the operating state of the engine shifts to the natural supercharging region and the electric supercharger is stopped, it is possible to prevent an excessive temperature rise due to the electric supercharger operating continuously for a long time.
Further, at this time, the intake air control means is controlled so as to maintain the engine output before increasing the gear ratio, so that the engine can be shifted to the natural air supply region without deteriorating the driving feeling.

According to the vehicle powertrain control device of the second aspect, since the increase in the engine speed is reduced compared with the case where the gear ratio is increased for a while even when entering the natural air supply region, the engine accompanying the increase in the gear ratio. The increase in the rotational speed can be reduced as much as possible, and the decrease in driving feeling due to the increase in the engine rotational speed can be minimized.
According to the powertrain control device for a vehicle of claim 3, when increasing the speed ratio of the transmission and increasing the engine speed, the engine speed is continuously increased by continuously increasing the speed ratio. Since it can raise, the fall of the driving | operation feeling at the time of engine speed rise can be suppressed.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an overall configuration diagram of a vehicle powertrain control device according to an embodiment of the present invention.
As shown in FIG. 1, the power train 1 of this embodiment includes an in-line four-cylinder engine 2 that uses gasoline as fuel, an electromagnetic clutch 4, and a continuously variable transmission (CVT) 6 that can continuously change the gear ratio. I have.

The output shaft 8 of the engine 2 is coupled to the input shaft 10 of the continuously variable transmission 6 via the electromagnetic clutch 4, and the driving force of the engine 2 is transmitted via the electromagnetic clutch 4 when the electromagnetic clutch 4 is in the connected state. The vehicle is driven by being transmitted to the continuously variable transmission 6 and the driving force output from the continuously variable transmission 6 is transmitted to wheels (not shown).
The intake passage 12 of the engine 2 is equipped with an electric supercharger 16 driven by an electric motor 14, and the air sucked from the air cleaner 18 is supercharged by the electric supercharger 16 and then for each cylinder. It is supplied to the combustion chamber (not shown) of the engine 2 through the branched intake manifold 20.

An electronically controlled throttle valve (intake air control means) 24 whose opening is controlled by an electric actuator 22 is interposed in the intake passage 12 downstream of the electric supercharger 16. Is controlled to adjust the intake air amount of the engine 2.
The bypass passage 26 that connects the upstream side and the downstream side of the electric supercharger 16 is provided with a reed valve 28 that allows only the flow from the upstream side to the downstream side of the electric supercharger 16. When the electric supercharger 16 is in a stopped state, the intake air is supplied via the bypass passage 26 in addition to the intake air supplied via the electric supercharger 16.

On the other hand, the exhaust gas of the engine 2 reaches the catalyst 34 from the exhaust manifold 30 through the exhaust passage 32, and is then discharged to the outside through a silencer (not shown).
The ECU (control means) 36 starts operation control of the engine 2 such as opening control of the throttle valve 24, fuel injection control, and ignition timing control, speed ratio control of the continuously variable transmission 6, and connection control of the electromagnetic clutch 4. The control device is configured to perform comprehensive control, and includes a CPU, a memory, a timer counter, and the like. The control device calculates various control amounts and controls various devices based on the control amounts.

  On the input side of the ECU 36, in order to collect information necessary for various controls, a vehicle speed sensor 38 that detects the traveling speed of the vehicle, an engine speed sensor 40 that detects the speed of the engine 2, and an accelerator pedal ( Various sensors such as an accelerator position sensor 42 for detecting a depression amount (not shown) are connected. On the output side, in addition to the electric motor 14 of the electric supercharger 16, the electric actuator 22 of the throttle valve 24, the electromagnetic clutch 4, and the continuously variable transmission 6 that are controlled based on the calculated control amount, the fuel injection of each cylinder is performed. Various devices such as a valve and a spark plug (not shown) are connected.

  In the engine 2 of the power train 1 configured as described above, based on the engine load and the engine speed, a supercharging region where the electric supercharger 16 is operated to perform supercharging, and the electric supercharger 16 is stopped. Thus, a natural air supply area where supercharging is not performed is set in advance. And if it determines with the driving | running state of the engine 2 being in a supercharging area | region based on an actual engine load and an engine speed, supercharging by the electric supercharger 16 will be performed by ECU36 controlling the electric motor 14, If it is determined that the operating state of the engine 2 is in the natural air supply region, the electric supercharger 16 is stopped, and intake air that is not supercharged is supplied to the engine 2 via the electric supercharger 16 and the bypass passage 26.

The control of the power train 1 including the control of the electric supercharger 16 is performed at a predetermined control cycle according to the flowchart shown in FIG.
In the first step S2, it is determined whether or not the current operating state of the engine 2 is in the supercharging region. Specifically, based on the engine load based on the accelerator pedal depression amount detected by the accelerator position sensor 42 and the engine speed detected by the engine speed sensor 40, whether or not the engine 2 is in the supercharging region. Determine whether.

The supercharging region and the natural air supply region are set in advance as shown in FIG. 3 based on the engine load and the engine speed. In FIG. 3, the broken line is a boundary line between the supercharging area and the natural air supply area, and the upper side from the broken line is the supercharging area.
Here, for example, if the operating state of the engine 2 is at point A (white circle) shown in FIG. 3 and it is determined in step S2 that the operating state of the engine 2 is in the supercharging region, the routine proceeds to step S4 and the requested supercharging Determine the pressure. This required supercharging pressure is a supercharging pressure that is currently required, and is based on the accelerator pedal depression amount detected by the accelerator position sensor 42 and the engine speed detected by the engine speed sensor 40. , Read from a preset map and determined.

Next, when proceeding to step S6, the intake air of the supercharging pressure corresponding to the required supercharging pressure is controlled by controlling the electric motor 14 of the electric supercharger 16 so that the required supercharging pressure determined in step S4 is obtained. Is supplied to the engine 2.
In the next step S8, it is determined whether or not the vehicle is in a predetermined steady running state. Specifically, the change amount per unit time of the depression amount of the accelerator pedal detected by the accelerator position sensor 42 is less than a predetermined change amount, and the vehicle travel speed detected by the vehicle speed sensor 38 per unit time. When the speed change amount is less than the predetermined speed change amount, that is, when the vehicle is not in the acceleration / deceleration running state, it is determined that the vehicle is in the steady running state.

Therefore, in the present embodiment, the ECU 36 corresponds to the steady running state determination means.
If it is determined in step S8 that the vehicle is in a steady running state, the process proceeds to step S10 and the gear ratio of the continuously variable transmission is increased by a predetermined gear ratio. Since the vehicle is running and the electromagnetic clutch 4 is in a connected state, the rotational speed of the engine 2 increases due to such an increase in the gear ratio.

In the next step S12, the electric actuator 22 of the throttle valve 24 is controlled to maintain the engine output before the increase of the gear ratio in step S10, the current control cycle is terminated, and the next control cycle starts again from step S2. Start processing.
The curve shown by the solid line in FIG. 3 is an engine iso-output line, and is shown in FIG. 3 by increasing the engine speed in step S10 and maintaining the engine output in step S12 as described above. The engine operating state moves on the iso-output curve from the point A (white circle) toward the natural air supply region.

  If the operating state of the engine 2 is still in the supercharging region even in the next control cycle, after the electric supercharger 16 is controlled in step S4 and step S6, is the vehicle in a steady running state in step S8? Determine whether or not. If the vehicle continues to be in a steady running state, the gear ratio of the continuously variable transmission 6 is increased by a predetermined gear ratio in step S10, and the engine output is maintained by controlling the throttle valve 24 in step S12.

  By repeatedly performing the processing of step S10 and step S12 in this way, the gear ratio of the continuously variable transmission 6 gradually increases and the engine speed increases while the engine output is maintained constant. At this time, the operating state of the engine 2 in FIG. 3 continues to move from the point A (white circle) on the iso-output curve in the direction of the natural air supply region. When the boundary line is exceeded (point B), it is determined in step S2 immediately after that that the engine 2 is not in the supercharged area, and in this case, the process proceeds to step S14.

In step S14, since the engine 2 is in the natural supercharging region, the operation of the electric motor 14 is stopped, the supercharging by the electric supercharger 16 is stopped, and the process proceeds to the next step S16.
In step S16, it is determined whether or not the vehicle is in a steady running state as in step S8 described above. If the vehicle continues to be in a steady running state, the current control cycle is terminated, and the process starts again from step S2 in the next control cycle. Therefore, in this case, the speed ratio set in step S10 and the throttle valve opening set in step S12 are maintained in the control cycle immediately before entering the natural air supply range.

  Thus, when the vehicle is in a steady running state, the driver 2 feels uncomfortable by shifting the operating state of the engine 2 from the supercharging region to the natural air supply region while maintaining the output of the engine 2. Therefore, it is possible to shift to a natural air supply region where the electric supercharger 16 is not used. The transition to the natural air supply region prevents the electric supercharger 16 from being used continuously for a long time, and the temperature of the electric supercharger 16 rises excessively and breaks or discharges the battery excessively. It is possible to prevent the occurrence of such a problem.

Further, when the engine speed is increased, the discoloration ratio of the continuously variable transmission 6 is gradually increased, so that the engine speed increases smoothly and this also gives the driver a sense of incongruity. There is no.
Further, as soon as the operating state of the engine 2 shifts to the natural air supply range, the increase in the engine speed due to the increase in the gear ratio is stopped, so that the change in the engine speed is suppressed to the minimum necessary and the engine speed is increased. It is possible to suppress a decrease in driving feeling caused by a change in the number.

  In the flowchart of FIG. 2, it is determined in step S2 that the operating state of the engine 2 is in the supercharging region, and supercharging is performed by the electric supercharger 16 in steps S4 and S6. If it is determined that the vehicle is not in the steady running state, the process proceeds to step S18. In step S <b> 18, normal shift control corresponding to the traveling state of the vehicle is performed on the continuously variable transmission 6 based on the accelerator pedal depression amount, the vehicle speed, and the like. Since this shift control is a well-known one that has been conventionally performed, a description thereof is omitted here.

In the next step S20, the normal throttle valve 24 is controlled in accordance with the accelerator pedal depression amount, the operating state of the engine 2, and the like, and the current control cycle is ended. Since this throttle valve control is also a well-known one that has been conventionally performed, the description thereof is omitted here.
Further, when it is determined in step S2 that the operating state of the engine 2 is not in the supercharging region, and in step S14, after the supercharging by the electric supercharger 16 is stopped, it is determined in step S16 that the vehicle is not in the steady running state. In addition, in step S18 and step S20, normal shift control and normal throttle valve control are performed, and the current control cycle is terminated.

Although the description of the vehicle powertrain control device according to one embodiment of the present invention has been completed, the present invention is not limited to the above-described embodiment.
For example, in the above embodiment, a continuously variable transmission is used as the transmission, but the present invention can also be applied to a transmission using a stepped transmission. In this case, since the engine speed gradually increases by gradually downshifting the transmission, the driving feeling is inferior to that of using a continuously variable transmission. A similar effect can be obtained in terms of preventing an excessive temperature rise and battery overdischarge.

  In the above embodiment, it is determined that the vehicle is in a predetermined steady state based on the amount of depression of the accelerator pedal and the amount of change per unit time of the vehicle traveling speed. Only when the depressing amount is less than the predetermined depressing amount, it is determined that the vehicle is in the steady driving state, so that it is not included in the steady driving state not only during acceleration / deceleration driving but also when traveling on an uphill road or at high speed. Also good.

  Further, the predetermined depression amount may be corrected in accordance with the traveling speed of the vehicle, and the predetermined depression amount may be increased as the vehicle travels at a higher speed so that the steady traveling state is included during high speed traveling. On the other hand, in order to exclude the traveling time on the uphill road from the steady running state, a sensor for detecting the tilt angle in the front-rear direction of the vehicle is provided. You may make it exclude from a state.

  Further, in the above-described embodiment, the supercharging by the electric supercharger 16 is stopped as soon as the operation state of the engine 2 shifts from the supercharging region to the natural air supply region, and the engine due to the increase in the gear ratio of the continuously variable transmission 6 Although the increase in the rotational speed is stopped, the engine speed increases due to an increase in the gear ratio and for a while after the transition to the natural air supply range and the supercharging by the electric supercharger 16 is stopped, and the throttle valve 24 The engine output may be maintained and the operating state of the engine 2 may be shifted to the best fuel consumption point in the natural air supply range. By doing in this way, although the driving | operation feeling falls with the increase width increase of an engine speed arises, it becomes possible to improve a fuel consumption.

  Further, in the above embodiment, the electronic throttle valve 24 is used as the intake air control means of the present invention. However, a flow rate control valve is provided in a passage bypassing the throttle valve 24 to control the intake air amount. Good.

1 is an overall configuration diagram of a vehicle powertrain control device according to an embodiment of the present invention. It is a flowchart which shows the control in the powertrain control apparatus for vehicles of FIG. It is a figure which shows the change of the engine driving | running state by control of FIG.

Explanation of symbols

1 Powertrain 2 Engine 6 Continuously variable transmission (transmission)
12 Intake passage 16 Electric supercharger 24 Throttle valve (intake air control means)
36 ECU (control means, steady running determination means)

Claims (3)

An electric supercharger that is provided in an intake passage of an engine mounted on a vehicle and is supercharged by intake air of the engine by being driven by an electric motor;
An intake air control means provided in the intake passage for controlling an intake air amount of the engine;
A transmission for shifting the output rotation of the engine and transmitting it to the wheels of the vehicle;
Steady running determination means for determining that the vehicle is in a predetermined steady running state;
Based on the operating state of the engine, a supercharging region where supercharging is performed by the electric supercharger and a natural air supply region where supercharging is not performed are defined, and the electric supercharging is performed when the engine is in the supercharging region. Control means for stopping the electric supercharger when the engine is in the natural air supply range, while performing supercharging by operating a machine,
The control means determines that the steady running determination means is in the steady running state when the engine operating state is in the supercharging region and the electric supercharger is operating . Until the operating state shifts to the natural air supply range, the transmission gear ratio is increased to increase the engine speed, and the intake air is maintained so as to maintain the engine output before the transmission ratio change. A vehicle powertrain control device for controlling a control means.   2. The vehicle according to claim 1, wherein the control unit stops the increase of the speed ratio and the control of the intake air control unit as soon as an operating state of the engine enters the natural air supply range. Powertrain control device.   The vehicle powertrain control device according to claim 1, wherein the transmission is a continuously variable transmission.

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