JP5490053B2 - Vehicle control device - Google Patents

Description

  The present invention relates to a vehicle control device, and more particularly to a vehicle control device that controls an electrically assisted turbocharger and an automatic transmission in accordance with the driving state of the vehicle.

  Generally, in order to increase the engine output, an exhaust turbocharger is provided in the intake passage to increase the intake pipe pressure, which is the pressure of the intake air drawn into the engine cylinder, and supercharge the intake air into the cylinder. It is known to do. Furthermore, in order to eliminate the turbo lag, which is a supercharge response delay that occurs when the exhaust turbocharger is driven only by exhaust gas energy, and the output decrease in the low rotation range, the exhaust turbocharger can also be driven by an electric motor. A technique using the electrically assisted turbocharger is known.

  By using an electrically assisted turbocharger, even a small displacement engine can achieve the same output as a conventional natural intake large displacement engine, while maintaining a high output and a small displacement engine. This makes it possible to reduce fuel consumption.

  In a control apparatus for a vehicle equipped with an engine using such an electric assist turbocharger, conventionally, when the battery charge amount falls below a predetermined value due to the use of the electric assist turbocharger, the shift control change means changes the speed. There is disclosed a technique for performing a control for changing the shift pattern of the machine to facilitate downshifting (see, for example, Patent Document 1).

JP 2007-231853 A

  According to the conventional vehicle control device disclosed in Patent Document 1, when the charge amount of the battery falls below a predetermined value due to the use of the electrically assisted turbocharger, the shift map is shifted so as to be easily downshifted. As a result, the engine speed increases, and the output required by supercharging only with the exhaust gas energy can be generated without generating the assist torque by the electric motor. Further, the amount of power generated by the increase in the engine speed The amount of charge to the battery can be secured by increasing the engine speed, but the shift of the shift map changes the speed of the driver to deteriorate, and the change in the engine operating point makes the engine inefficient in combustion efficiency. Could work with.

  The present invention has been made to solve the above-described problems in the conventional apparatus, and provides a vehicle control apparatus that can secure the amount of charge of a battery without impairing the driver's sense of driving performance. It is for the purpose.

A vehicle control apparatus according to the present invention includes:
An electrically assisted turbocharger that is driven by at least one of a driving force by an exhaust gas energy of an engine mounted on a vehicle and a driving force by an electric motor to compress intake air in an intake passage and supercharge the cylinder in the engine; A vehicle control device comprising: an automatic transmission that controls a gear ratio based on a set shift map; and a control unit that controls the electric motor and the automatic transmission based on a driving state of the vehicle,
The control means includes
At least of the engine operating point based on the shift map that has already been set , the power supplied to the electric motor, the amount of power generated by the alternator driven by the engine and the amount of power stored in the battery charged by the alternator On the other hand, the fuel consumption including the power generation amount of the alternator based on the new engine operating point in consideration of the power generation amount of the alternator, assuming that the shift map is changed while maintaining the same vehicle speed based on Calculate the rate,
When the calculated fuel consumption rate is smaller than the fuel consumption rate before changing the shift map, the automatic transmission is controlled so as to change the shift map, and based on the changed shift map, the automatic transmission is controlled. Change the power supply to the motor,
When the calculated fuel consumption rate is not smaller than the fuel consumption rate before changing the shift map, the shift map is not changed.
It is characterized by this.

According to the vehicle control apparatus of the present invention, the engine operating point based on the already set shift map , the electric power supplied to the electric motor, the amount of power generated by the alternator driven by the engine and the battery charged by the alternator The amount of power generated by the alternator based on a new engine operating point in consideration of the amount of power generated by the alternator, assuming that the shift map is changed while maintaining the same vehicle speed based on at least one of If the calculated fuel consumption rate is smaller than the fuel consumption rate before changing the shift map, the automatic transmission is controlled to change the shift map, Based on the changed shift map, the power supplied to the electric motor is changed, and the calculated fuel consumption rate changes the shift map. If the not smaller than the fuel consumption rate, than was to not change the shift map, when the fuel economy by changing the shift map is worse, without changing the shift map, the power generation of the alternator By increasing the electric assist turbocharger and continuously driving the battery, even when the amount of charge of the battery is small, it is possible to suppress the deterioration of the fuel consumption of the vehicle as much as possible by using an operating point with excellent engine combustion efficiency.

1 is a configuration diagram illustrating an entire vehicle system including a vehicle control device according to Embodiment 1 of the present invention; It is explanatory drawing which shows the operating point change of the engine in the control apparatus of the vehicle by Embodiment 1 of this invention. It is explanatory drawing which shows the shift map change of the automatic transmission in the vehicle control apparatus by Embodiment 1 of this invention. It is a flowchart which shows an example of operation | movement of the electric motor control apparatus in the control apparatus of the vehicle by Embodiment 1 of this invention. It is explanatory drawing which shows the fuel consumption rate map in the operating point of the engine in the control apparatus of the vehicle by Embodiment 1 of this invention.

Embodiment 1 FIG.
Hereinafter, a vehicle control apparatus according to Embodiment 1 of the present invention will be described in detail. 1 is a configuration diagram showing an entire vehicle system including a vehicle control apparatus according to Embodiment 1 of the present invention. An engine 2 as a main component of the internal combustion engine 1 shown in FIG. 1 is a four-cylinder gasoline engine. By supercharging intake air into the cylinder using an electrically assisted turbocharger 5, the engine can be increased and output can be increased. The fuel consumption is reduced by reducing the engine displacement.

  The engine 2 applied to the vehicle control apparatus according to the present invention is not limited in the number of cylinders, and there is no limitation on the combustion method of the engine 2, and a direct injection engine that directly injects fuel into the cylinder is applied. Alternatively, a port injection engine in which fuel is injected into the intake manifold 17 on the downstream side of the throttle valve 11 may be applied.

  In FIG. 1, an intake passage 3 and an exhaust passage 4 are connected to the cylinder portion 2 of the engine 2. An electrically assisted turbocharger 5 is provided between the intake passage 3 and the exhaust passage 4. The electrically assisted turbocharger 5 is connected coaxially to the turbine wheel 6 via a rotating shaft 7 and a turbine wheel 6 that is driven and rotated by exhaust gas energy generated in each cylinder of the cylinder portion 2. Thus, a compressor wheel 8 for compressing intake air in the intake passage 3 and an electric motor 9 for applying electric assist torque to the rotary shaft 7 are provided. Note that at least one of the turbine wheel 6 and the compressor wheel 8 may be a variable vane system in which the impeller angle can be changed.

  The electric assist turbocharger 5 is based on only the driving torque based on the exhaust gas energy generated in the cylinder unit 2, only based on the driving torque of the electric motor 9, or the total torque of the driving torque based on the exhaust gas energy and the electric assist torque generated by the electric motor. Thus, the compressor wheel 8 can be driven to compress the intake air passing through the intake passage 3, and the compressed intake air can be supercharged into the cylinder.

  The electric assist turbocharger 5 supercharges the intake air in the intake passage 3 by the rotational drive of the electric motor 9 when the engine 2 rotates at a low speed, and supercharges the intake air in the intake passage 3 by the exhaust gas energy when the engine 2 rotates at a high speed. Although it is based on this, depending on the case, the electric assist torque by the electric motor 9 and the driving torque by the exhaust gas energy may be always superposed and supercharged regardless of the rotational speed of the engine 2.

  An intercooler 10 for cooling the intake air is provided downstream of the compressor wheel 8 in the intake passage 3. A throttle valve 11 for adjusting the flow rate of intake air flowing through the intake passage 3 is provided on the downstream side of the intercooler 10 in the intake passage 3. A throttle valve actuator 12 that opens and closes the throttle valve 11 is attached to the throttle valve 11. The intake passage 3 on the downstream side of the throttle valve 11 forms an intake manifold 17 branched according to each cylinder of the cylinder portion 2.

  An exhaust manifold 18 branched in accordance with each cylinder of the cylinder portion 2 is formed on the upstream side of the exhaust passage 4. Further, a waste gate valve 15 and a waste gate valve actuator 14 that opens and closes the waste gate valve 15 are attached to the exhaust passage 4.

  Here, the flow until the intake air taken into the intake passage 3 of the engine 2 is discharged from the exhaust passage 4 will be described. First, dust is removed from the intake air taken into the intake passage 3 from the atmosphere by an air cleaner (not shown). Subsequently, the intake air from which the dust has been removed is compressed by the rotation of the compressor wheel 8 of the electric assist turbocharger 5.

  Next, the compressed intake air rises in temperature and expands due to an increase in pressure, but is cooled by the intercooler 10 in order to improve the intake charge efficiency of the engine. The flow rate of the cooled intake air is adjusted according to the opening degree of the throttle valve 11 driven by the throttle valve actuator 12, and in the case of a port injection engine, fuel is mixed to become an air-fuel mixture, Inhaled.

  Next, the air-fuel mixture sucked into the cylinder is ignited by an ignition device, and a piston (not shown) in the cylinder is pushed down. Subsequently, the vertical motion of the piston is converted into a rotational motion by a crank (not shown), and the crank of the engine 2 rotates. The rotation of the engine 2 is changed in gear ratio by the automatic transmission 25, and the power is transmitted to the drive wheels 27 through the power transmission path 26, which is used as power for propelling the vehicle.

  The crankshaft of the engine 2 is connected to an alternator 23 via a belt 24, and the alternator 23 is driven by engine power via the belt 24 to generate electric power. The electric power generated by the alternator 23 is charged in the battery 22 and supplies power to devices that require electric power, such as the electric assist turbocharger 5 and other on-vehicle auxiliary machines (not shown).

  Exhaust gas generated by the combustion of the air-fuel mixture in the cylinder is exhausted through the exhaust manifold 18. Subsequently, when the wastegate valve 15 is closed, the exhaust gas passes through the turbine wheel 6 of the electric assist turbocharger 5 and rotates the turbine wheel 6. The exhaust gas is guided to the bypass 21 when the wastegate valve 15 is open. The exhaust gas that has rotated the turbine wheel 6 and the exhaust gas that has passed through the bypass 21 merge, and are purified by a muffler (not shown) integrated with an exhaust gas purification catalyst and the like, and are discharged into the atmosphere.

  The opening degree of the wastegate valve 15 is controlled by the wastegate valve actuator 14 based on the rotational speed of the engine 2 and the like, and the flow rate of the exhaust gas to the turbine wheel 6 is adjusted. The wastegate valve actuator 14 is controlled by a vehicle control device as control means described later.

In addition, when the exhaust gas energy is sufficient, the electric assist turbocharger 5 drives the rotor of the electric motor 9 simultaneously with the driving of the turbine wheel 6 by the exhaust gas energy, and charges the battery 22 by the regenerative electric power of the electric motor 9. The

  An electric motor control device 19 is connected to the electric motor 9 of the electric assist turbocharger 5, and a vehicle control device 20 is connected to the electric motor control device 19. The electric motor control device 19 and the vehicle control device 20 are configured by an arithmetic logic operable circuit including a CPU, a RAM, a ROM, and the like. In the first embodiment, the control means for controlling the electric motor 9 and the automatic transmission 25 of the electric assist turbocharger 5 includes a vehicle control device 20 and an electric motor control device 19.

  An engine 2, an electric motor 9, a throttle valve actuator 12, a waste gate valve actuator 14, a battery 22, an alternator 23, and an automatic transmission 25 are connected to the vehicle control device 20.

  The vehicle control device 20 obtains the engine operating point including the engine speed and the engine output from the engine 2, the power consumption of the motor 9 from the motor control device 19, the battery charge amount from the battery 22, and the power generation amount from the alternator 23. Then, the vehicle control device 20 outputs a command for controlling the driving of the electric motor 9 to the electric motor control device 19, outputs an electric power generation amount control command to the alternator 23, and sets a shift map to the automatic transmission 25. Further, the vehicle control device 20 outputs a command for controlling the opening degree of the throttle valve 11 to the throttle valve actuator 12 and outputs a command for controlling the opening degree of the waste gate valve 15 to the waste gate valve actuator 14.

  Here, the change of the shift map will be described. The change of the shift map is performed for the purpose of suppressing power consumption by the electric motor 9 of the electric assist turbocharger 5. By changing the shift map, the electric assist torque by the electric motor 9 is compressed while maintaining the same vehicle speed. The engine is moved to an engine operating point where supercharging in addition to the wheel is unnecessary, or to an engine operating point where the electric assist torque is reduced.

  FIG. 2 is an explanatory diagram showing engine operating point change in the vehicle control apparatus according to Embodiment 1 of the present invention. In FIG. 2, the vertical axis represents engine torque (Nm), and the horizontal axis represents engine speed (rpm). The electric supercharging region A is a region in which the electric assist torque from the electric motor 9 is applied to the compressor wheel 7 for supercharging, and the exhaust supercharging region B is only applied to the exhaust gas energy of the engine 2 without applying the electric assist torque. The non-supercharging region C is a region where supercharging is not required.

  As shown in FIG. 2, for example, when the vehicle speed is kept constant along the vehicle isovelocity line, the electric assist torque is applied to the compressor wheel at the high gear operating point in the electric supercharging region A. At the low gear operating point in the exhaust supercharging region B, electric supercharging is unnecessary and supercharging is performed only by the exhaust gas energy. There is no salary.

  FIG. 3 is an explanatory diagram showing a shift map change of the automatic transmission in the vehicle control apparatus according to Embodiment 1 of the present invention, where the vertical axis represents the accelerator opening (%) and the horizontal axis represents the vehicle speed (km / h). The explanatory diagram shown in FIG. 3 shows a shift map in a specific gear of a general vehicle, and a shift line is determined according to the vehicle speed and the throttle opening. In order to increase the engine speed on the constant vehicle speed line, the shift line is continuously changed so that the vehicle speed increases and the throttle opening decreases. The shift line includes a downshift line that is determined based on the timing of downshifting from the high gear to the low gear, and an upshift line that is determined based on the timing of upshifting from the low gear to the high gear. .

  Next, the operation of the vehicle control apparatus according to Embodiment 1 of the present invention will be described. FIG. 4 is a flowchart showing an example of the operation of the electric motor control apparatus in the vehicle control apparatus according to Embodiment 1 of the present invention. The flowchart shown in FIG. 4 is a routine that is repeatedly executed every predetermined short time.

  In FIG. 4, first, in step S <b> 201, the vehicle control device 20 acquires driving state information from a device mounted on the vehicle. Specifically, information on the engine speed and engine output as the engine operating point from the engine 2, information on the power consumption of the motor 9 from the motor control device 19, information on the battery charge from the battery 22, Information on the amount of power generated by the alternator is obtained from the alternator 23, respectively.

  Next, in step S <b> 202, it is determined whether or not the charge amount of the battery 22 is sufficient power for driving the electric assist turbocharger 5. Here, the determination is made based on whether or not the amount of electricity stored in the battery 22 is less than the predetermined value α. As a result of the determination in step S202, when it is determined that the battery charge amount of the battery 22 is less than the predetermined value α (YES), the process proceeds to step S203, and the charge amount of the battery 22 of the battery 22 is greater than or equal to the predetermined value α. If it is determined (NO), the flowchart of FIG.

  In step S203, the power generation amount margin of the alternator 23 is determined. Here, the determination is made based on whether or not the power generation amount of the alternator 23 exceeds a predetermined value β. When it is determined in step S203 that the power generation amount of the alternator exceeds the predetermined value β (YES), the process proceeds to step S204, and it is determined that the power generation amount of the alternator is equal to or less than the predetermined value β. In (NO), the flowchart of FIG. 2 is ended as it is.

  In step S204, when the electric power for driving the electric assist turbocharger without changing the shift map is generated by the alternator and the electric power for driving the electric assist turbocharger by changing the shift map is reduced. Calculate the fuel consumption of Next, the calculation method will be described.

  FIG. 5 is an explanatory diagram showing a fuel consumption rate map at the operating point of the engine in the vehicle control apparatus according to Embodiment 1 of the present invention. The vertical axis represents engine torque (Nm), and the horizontal axis represents engine rotation. Number (rpm) is shown. As shown in FIG. 5, if the operating point of the engine is moved in a direction approaching a region with good fuel efficiency of the fuel consumption rate map, the fuel efficiency is improved, and if moving in a direction away from the region with good fuel efficiency, the fuel efficiency is deteriorated. .

Therefore, in step S204 of FIG. 4, the necessary input to the alternator 23 is calculated from the power load, and the fuel consumption rate at the engine operating point including power generation is determined from the fuel consumption rate map shown in FIG. The fuel consumption at the engine operating point is estimated, and it is determined whether or not the fuel consumption is improved by changing the shift map . As a result, if it is determined that the fuel economy is improved (YES) by changing the shift map, the process proceeds to step S205, in a case where fuel consumption by shifting the shift map is determined not improved (NO), as it The flowchart of FIG. 2 is terminated.

  In step S205, the shift map is continuously changed according to the power load, and the power to the electrically assisted turbocharger is reduced. Here, the power load refers to the driving power for the electric motor 9 of the electric assist turbocharger 5 to generate electric assist torque, the amount of electricity stored when the charge amount of the battery 22 is below a predetermined value α, and the alternator. When the power generation amount of 23 exceeds the predetermined value β, the power generation amount exceeding the predetermined value β is indicated. In step S205, the shift map is continuously moved based on at least one of these electric power loads, and the electric power consumed by the electric motor 9 in the electric assist turbocharger 5 is reduced.

  For example, the drive power of the electric motor 9 of the electric assist turbocharger 5 is large, the amount of charge of the battery is smaller than a predetermined value, and the amount of power generation of the alternator is larger than the predetermined value. Alternatively, as any one of these increases, the shift amount of the shift line shown in FIG. 3 is increased to limit the operation of the electric assist turbocharger, and the drive power to the electric motor 9 of the electric assist turbocharger 5 is reduced. Then, the flowchart of FIG.

  In the flowchart of FIG. 4, both step S202 for determining the charge amount of the battery 22 and step S203 for determining the power generation amount of the alternator 23 are provided. However, only one of step S202 and step S203 is provided. It is good also as the flowchart which becomes. In this case, the same effect as that of the first embodiment can be obtained.

  Further, as described above, the shift line has a downshift line that is set based on the timing of downshifting from the high gear to the low gear, and an upset that is set based on the timing of upshifting from the low gear to the high gear. Although there is a shift line, changing the upshift line increases the frequency of traveling in low gear and deteriorates the fuel consumption. Therefore, the shift map may be changed only on the downshift line. In this case, the same effect as that of the first embodiment can be obtained.

  Furthermore, not only the electrically assisted turbocharger 5 but also a mechanical turbocharger may be further provided in the subsequent stage or the preceding stage of the electrically assisted turbocharger 5 to constitute a so-called twin charger. In this case, the same effect as that of the first embodiment can be obtained.

  Further, in the first embodiment described above, the motor control device 19 and the vehicle control device 20 have been described as separate ones. However, the present invention is not limited to this. For example, when functions can be integrated into the vehicle control device 20 or the like, The electric motor control device 19 may function as a simple driver that drives the electric motor 9. Also in this case, the same effect as in the first embodiment can be obtained.

  Furthermore, in the first embodiment described above, the automatic transmission 25 has been described as having a stepped gear. However, the present invention is not limited to this, and may be an automatic transmission of a continuously variable gear such as CVT. In this case, since the shift map can be continuously changed and the gear ratio can be changed, in addition to the effect of the first embodiment described above, an effect of further improving the driving performance of the driver can be obtained.

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Engine 3 Intake passage 4 Exhaust passage 5 Electric assist turbocharger 6 Turbine wheel 7 Rotating shaft 8 Compressor wheel 9 Electric motor 10 Intercooler 11 Throttle valve 12 Throttle valve actuator 14 Waste gate valve actuator 15 Waste gate valve 17 Intake manifold 18 Exhaust manifold 19 Motor controller 20 Engine controller 21 Bypass 22 Battery 23 Alternator 24 Belt 25 Automatic transmission 26 Power transmission path 27 Drive wheel

Claims (1)

An electrically assisted turbocharger that is driven by at least one of a driving force by an exhaust gas energy of an engine mounted on a vehicle and a driving force by an electric motor to compress intake air in an intake passage and supercharge the cylinder in the engine; A vehicle control device comprising: an automatic transmission that controls a gear ratio based on a set shift map; and a control unit that controls the electric motor and the automatic transmission based on a driving state of the vehicle,
The control means includes
At least of the engine operating point based on the shift map that has already been set , the power supplied to the electric motor, the amount of power generated by the alternator driven by the engine and the amount of power stored in the battery charged by the alternator On the other hand, the fuel consumption including the power generation amount of the alternator based on the new engine operating point in consideration of the power generation amount of the alternator, assuming that the shift map is changed while maintaining the same vehicle speed based on Calculate the rate,
When the calculated fuel consumption rate is smaller than the fuel consumption rate before changing the shift map, the automatic transmission is controlled so as to change the shift map, and based on the changed shift map, the automatic transmission is controlled. Change the power supply to the motor,
When the calculated fuel consumption rate is not smaller than the fuel consumption rate before changing the shift map, the shift map is not changed.
A control apparatus for a vehicle.

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