JP2010077879A - Vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle capable of improving the fuel economy of an internal combustion engine by increasing the quantity of exhaust gas which can be introduced to an intake system from an exhaust system. <P>SOLUTION: The vehicle includes the internal combustion engine 10 having an EGR system introducing part of exhaust gas from the exhaust system to the intake system, a motor 204 and a generator 202, and a navigation system 400 or a millimeter wave radar device 500 as an environmental information acquisition means acquiring the environmental information of the vehicle. ECU 100 determines whether the deceleration of the speed of a vehicle is predicted based on information acquired from the navigation system 400, and limits an exhaust gas introduction quantity if it is determined that the deceleration of the speed of the vehicle is predicted. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle, and more particularly, to a vehicle including an internal combustion engine, a motor, and / or a generator.

  In general, the EGR system recirculates a part of exhaust gas discharged from the engine from the exhaust pipe side to the intake pipe side through the EGR pipe, and sends the exhaust gas from the intake manifold to each cylinder of the engine. The combustion capacity is lowered by the heat capacity of the inert gas constituting the part, NOx in the exhaust gas is reduced, and unburned fuel contained in the exhaust gas is burned to improve fuel consumption. . The technology related to the EGR system is disclosed in, for example, Patent Documents 1 and 2.

JP 2006-194143 A JP 2004-1000046 A

  By the way, in an internal combustion engine equipped with an EGR system, when the vehicle starts decelerating when exhaust gas is introduced into the intake system, the throttle valve provided in the intake system is closed. For this reason, the pressure of the intake system downstream of the throttle valve is reduced, and the amount of exhaust gas recirculated to the intake system increases rapidly, which may cause misfire in the combustion chamber.

  For this reason, conventionally, the amount of exhaust gas introduced into the intake system is always limited to an amount that does not cause misfire.

  Therefore, since the amount of exhaust gas introduced into the intake system is limited, there has been a problem that the effect of improving the fuel consumption due to the exhaust gas circulation is not sufficient.

The present invention has been made in view of the above problems, and an object thereof is to provide a vehicle capable of improving the fuel consumption of an internal combustion engine by increasing the amount of exhaust gas that can be introduced from the exhaust system into the intake system. It is in.

  A vehicle according to the present invention includes an internal combustion engine including an exhaust gas recirculation unit that introduces a part of exhaust gas from an exhaust system to an intake system, a motor and / or a generator, and ambient information acquisition unit that acquires ambient information of the vehicle. , Based on the information obtained from the surrounding information acquisition means, the deceleration prediction means for determining whether or not the vehicle is expected to decelerate, and when the deceleration prediction means determines that the vehicle is expected to decelerate, And an introduction amount control means for limiting an exhaust gas introduction amount of the exhaust gas circulation means.

  In the above configuration, the introduction amount control means may employ a configuration in which the introduction amount of the exhaust gas is limited to such an extent that misfire does not occur in the internal combustion engine.

  In the above configuration, when the deceleration prediction unit determines that the vehicle is not expected to start deceleration, the valve control is performed so that the throttle valve provided in the intake system is gradually closed when vehicle deceleration is started. A configuration further having means can be adopted.

  In the above configuration, it is possible to adopt a configuration further including power distribution means for distributing the surplus torque generated when the throttle valve is gradually closed to the motor and / or generator.

  The said structure WHEREIN: The said deceleration prediction means can employ | adopt the structure containing at least one of a navigation system and a radar system.

  According to the present invention, the amount of exhaust gas introduced into the intake system can be increased to the maximum, and fuel efficiency can be improved.

  Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a configuration diagram of a vehicle according to an embodiment of the present invention.

  The vehicle includes an internal combustion engine 10, a catalyst 30 including a three-way catalyst for purifying exhaust gas provided in an exhaust pipe 20 of the internal combustion engine 10, and a drive shaft 50 to which rotational driving force is transmitted from a power transmission mechanism 200. A wheel 60 to which rotational torque is transmitted from the drive shaft 50, an electronic control unit (ECU) 100 for comprehensively controlling the vehicle, a power transmission mechanism 200, a navigation system 400, and a millimeter wave radar device 500 are provided. .

  The power transmission mechanism 200 includes a power split mechanism 201, a generator 202, a speed reducer 203 that decelerates the rotation transmitted from the power split mechanism 201 and transmits it to the drive shaft 50, an electric motor 204, an inverter 210, and a battery 220.

The power transmission mechanism 200 is controlled by the ECU 100.
The ECU 100 includes hardware such as a processor and a memory, and necessary software, and comprehensively controls the vehicle. As will be described later, the ECU 100 constitutes ambient information acquisition means, deceleration prediction means, introduction amount control means, valve control means, and power distribution means.

  The inverter 210 is controlled by the ECU 100 to perform direct current / alternating current conversion, and exchange power with the battery 220, the generator 202, and the motor 204.

  The battery 220 supplies the charged DC power to the inverter 210 and charges the DC power supplied from the inverter 210.

  The generator 202 generates power when the rotational torque is supplied from the power split mechanism 201. When AC power is supplied from inverter 210 to generator 202, it functions as a motor and can supply rotational torque to power split device 201.

  The electric motor 204 generates rotational torque when AC power is supplied from the inverter 210, and this rotational torque is supplied to the wheels 60 via the power split mechanism 201. Further, when rotational torque is supplied from power split mechanism 201 to electric motor 204, electric motor 204 can generate AC power and supply it to inverter 210.

  The power split mechanism 201 is controlled by the ECU 100 described above, and transfers power (rotational torque) between the internal combustion engine 10, the generator 202, the speed reducer 203, and the motor 204.

  For example, when starting the internal combustion engine 10, the power split mechanism 201 supplies the internal combustion engine 10 with rotational torque supplied from the generator 202 for cranking the internal combustion engine 10.

  Further, when the state of charge of the battery 220 decreases while the vehicle is stopped, the power of the internal combustion engine 10 is supplied to the generator 202 to generate power.

  Further, when the vehicle starts, during normal travel, etc., the rotational torque of the electric motor 204 is transmitted to the speed reducer 203 to rotate the drive shaft 50.

  In an efficient operating region of the internal combustion engine, such as during steady running, the power of the internal combustion engine 10 is transmitted to the speed reducer 203 to rotate the drive shaft 50 and a part of the power of the internal combustion engine 10 is sent to the generator 202. Supply. At this time, the rotational torque of the motor 204 can be additionally transmitted to the speed reducer 203.

  The navigation system 400 mainly uses an autonomous navigation device such as GPS (Global Positioning System), vehicle speed pulse, and gyro to guide the driver to the current position and destination on the display screen during vehicle operation. Travel route guidance is performed. Further, the navigation system 400 outputs current position information to the ECU 100.

  The millimeter wave radar device 500 is a radar mainly for the purpose of reducing the collision of a vehicle. The millimeter wave radar device 500 receives a radio wave reflected from an object by emitting a millimeter wave, and a frequency difference caused by a propagation time or a Doppler effect. Based on the above, the position of the object and the relative speed with the host vehicle are measured. The millimeter wave is a radio wave having a frequency of 30 to 300 GHz, and 76 to 77 GHz is mainly used as an in-vehicle millimeter wave radar.

  During normal driving, the vehicle speed is adjusted based on information obtained from the millimeter wave radar, and the distance between the vehicle and the preceding vehicle is kept constant. When a collision is about to occur, the condition is detected in advance and safety equipment such as brakes and seat belts are activated early.

  Further, the millimeter wave radar device 500 outputs information such as the distance between the preceding vehicle and the host vehicle to the ECU 100.

  FIG. 2 is a diagram showing a configuration of an EGR system as exhaust gas recirculation means provided in the internal combustion engine 10.

  The EGR system includes an EGR gas passage 14 that connects a downstream of the catalyst 30 in the exhaust passage 20 of the internal combustion engine 10 and an intake passage 18 of the internal combustion engine 10.

  The EGR gas passage 14 is connected to an intake passage 18 between a throttle valve 26 and a surge tank 24 provided downstream thereof.

  An EGR cooler 16 for cooling the EGR gas that is a part of the exhaust gas of the internal combustion engine 10 is provided in the middle of the EGR gas passage 14.

  At the outlet of the EGR gas passage 14 on the intake passage 18 side, an EGR valve 22 for adjusting the flow rate of EGR gas to the intake passage 18 is provided.

  The EGR valve 22 and the throttle valve 26 are controlled by the ECU 100 described above.

  Next, an example of EGR gas ring flow rate control by the ECU 100 will be described with reference to the flowchart of FIG. Note that the processing shown in FIG. 3 is repeatedly executed at predetermined time intervals.

  First, during operation of the vehicle, control is performed so that the maximum allowable amount of EGR gas G is introduced into the intake passage 18 (step S1).

  Next, information about the surroundings of the vehicle is sequentially acquired from the navigation system 400 and the millimeter wave radar device 500 (step S2).

  Next, it is predicted from the acquired surrounding information about the vehicle whether the vehicle will start decelerating (step S3).

  For example, when the current position of the vehicle obtained from the navigation system 400 approaches a place where a relatively long downhill continues, it can be predicted that deceleration will be started. Further, from the information of the millimeter wave radar device 500, when the distance between the host vehicle and the vehicle ahead is narrower than a predetermined distance, it can be predicted that deceleration will be started.

  In step S3, if it is expected that the host vehicle will start decelerating from now on, the amount of EGR gas G introduced into the intake passage 18 by controlling the EGR valve 22 as shown in FIG. Limit to the extent that misfire does not occur. Thus, when the host vehicle starts decelerating, the amount of EGR gas G introduced into the intake passage 18 is limited before the throttle valve 26 is suddenly closed. Thus, a large amount of EGR gas G is not introduced to the vehicle, and it is possible to reliably prevent misfire.

  Next, it is determined whether or not the deceleration has ended (step S8). If the deceleration has ended, the process ends. If it is determined that the deceleration has not ended, the process returns to step S3 to perform the same process. To do.

  On the other hand, if it is not predicted that deceleration will be started in step S3, it is determined whether there is a deceleration request from the driver of the vehicle, that is, whether the vehicle is decelerated from the state of the accelerator opening by the driver (step S5).

  In step S5, when there is no deceleration request, the process is terminated, and when there is a deceleration request, the throttle valve 26 is gradually closed so that misfire does not occur in the internal combustion engine 10 (step S6). That is, for example, as shown in FIG. 5, the throttle valve 26 is not closed according to the accelerator opening, but is gradually closed independently of the accelerator opening. Thereby, since the intake passage 18 downstream of the throttle valve 26 is not suddenly depressurized, a large amount of EGR gas G is not introduced into the combustion chamber of the internal combustion engine 10, and misfire can be reliably prevented. .

  When the throttle valve 26 is gradually closed, the braking force by the internal combustion engine 10 acting on the vehicle becomes small, so that excessive torque is generated. For this reason, the power split mechanism 201 described above is controlled so that the excess torque is absorbed by the electric motor 204 or the generator 202 (step S7). Then, it is determined whether or not deceleration has ended (step S8). If deceleration has ended, the process ends. If it is determined that deceleration has not ended, the process returns to step S3 to perform the same process. To do.

  In the above embodiment, the case where the millimeter wave radar device 500 is used has been described. However, a radar device other than the millimeter wave may be used.

  In the above embodiment, the case where each means of the present invention is configured by the ECU 100 has been described. However, the present invention is not limited to this, and each means may be configured by being distributed by different processors or the like. .

It is a figure which shows an example of the principal part structure of the vehicle to which this invention is applied. It is a figure which shows an example of the EGR system applied to the vehicle of FIG. It is a flowchart which shows an example of the process in ECU. It is a figure which shows the state which restrict | limited the exhaust gas ring flow volume of the EGR system. It is a timing chart which shows the relationship between the accelerator opening and slot valve opening in one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine 18 ... Intake passage 20 ... Exhaust passage 22 ... EGR valve 24 ... Surge tank 26 ... Throttle valve 30 ... Catalyst 100 ... ECU
DESCRIPTION OF SYMBOLS 200 ... Power transmission mechanism 201 ... Power split mechanism 202 ... Generator 203 ... Reduction gear 204 ... Electric motor 210 ... Inverter 220 ... Battery 400 ... Navigation system 500 ... Millimeter wave radar apparatus

Claims (5)

An internal combustion engine comprising exhaust gas recirculation means for introducing a part of the exhaust gas from the exhaust system into the intake system;
A motor and / or generator;
Surrounding information acquisition means for acquiring surrounding information of the vehicle;
Deceleration prediction means for determining whether deceleration of the vehicle is expected based on information obtained from the surrounding information acquisition means;
A vehicle comprising: an introduction amount control means for restricting an exhaust gas introduction amount of the exhaust gas recirculation means when the deceleration prediction means determines that deceleration of the vehicle is expected.   The vehicle according to claim 1, wherein the introduction amount control means limits the introduction amount of the exhaust gas to such an extent that misfire does not occur in the internal combustion engine.   When the deceleration prediction means determines that deceleration is not expected, the vehicle further includes valve control means for controlling the throttle valve provided in the intake system to close gradually when the vehicle starts to decelerate. The vehicle according to claim 1 or 2.   4. The vehicle according to claim 3, further comprising power distribution means for distributing surplus torque generated when the throttle valve is gradually closed to the motor and / or generator.   The vehicle according to any one of claims 1 to 4, wherein the deceleration prediction means includes at least one of a navigation system and a radar system.

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