JP6192462B2 - Vehicle control device - Google Patents

Description

  The present invention relates to a control device that controls a vehicle on which an internal combustion engine is mounted.

  In recent years, the pursuit of fuel efficiency of automobiles has been spurred, so control is performed to reduce the output of the internal combustion engine by reducing the throttle valve opening as much as possible in the partial load region of the internal combustion engine. .

  On the other hand, if the output of the internal combustion engine is suppressed to improve fuel efficiency, there is a concern that drivability may be reduced due to insufficient driving torque when traveling uphill. Therefore, when it is detected that the vehicle is located on an uphill road, the minimum target input rotation speed of the transmission is increased to prohibit inappropriate shift up, that is, by changing the gear ratio to low gear, (See, for example, the following patent document).

JP 2010-121696 A

  As described above, in the conventional control, the drive torque supplied to the axle is increased by shifting down the transmission when traveling uphill. However, the output of the internal combustion engine itself is controlled in the same way as when traveling on a flat road, and it does not increase the output of the internal combustion engine just because it is an uphill road. Therefore, some drivers may feel that the driving torque is insufficient during climbing.

  An object of the present invention made in view of the above is to improve the climbing performance of a vehicle.

In the present invention, when it is detected that the vehicle is on an uphill road and the accelerator pedal is depressed by the driver, the vehicle has the transmission gear ratio between the internal combustion engine and the axle. and sets the low shift closer as compared with the case present in a flat road, to increase the average output of the fan for sucking the outside air into the engine room as compared to the case where the vehicle is present on a flat road A vehicle control device characterized by the above is configured.

Lever raised output of the fan drawing outside air into the engine room of the vehicle, it is possible to lower the temperature in the engine room. As a result, the temperature of the intake air flowing through the intake passage of the internal combustion engine decreases, and the amount of intake air that fills the cylinders substantially increases. Accordingly, the fuel injection amount can be increased, so that the output of the engine obtained by burning the fuel increases.

  According to the present invention, it is possible to improve the climbing performance of a vehicle.

The figure which shows schematic structure of the internal combustion engine in one Embodiment of this invention. The figure which shows schematic structure of the drive system of the vehicle in the embodiment. The figure which shows schematic structure of the air conditioner of the vehicle in the embodiment. The electric circuit diagram of the air conditioner of the vehicle in the embodiment. The shift diagram of the automatic transmission which the control apparatus of the embodiment controls. The figure which shows the relational characteristic with the amount of accelerator pedal depressions of the throttle-valve opening degree which the control apparatus of the embodiment controls. The figure which shows the relationship characteristic with the request | requirement load of the EGR rate of the intake air by the EGR apparatus which the control apparatus of the embodiment controls.

  An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an outline of an internal combustion engine for a vehicle in the present embodiment. The internal combustion engine in the present embodiment is a spark ignition type 4-stroke gasoline engine, and includes a plurality of cylinders 1 (one of which is shown in FIG. 1). In the vicinity of the intake port of each cylinder 1, an injector 11 for injecting fuel is provided. A spark plug 12 is attached to the ceiling of the combustion chamber of each cylinder 1. The spark plug 12 receives spark voltage generated by the ignition coil and causes spark discharge between the center electrode and the ground electrode. The ignition coil is integrally incorporated in a coil case together with an igniter that is a semiconductor switching element.

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

  The exhaust passage 4 for discharging the exhaust guides the exhaust generated as a result of burning the fuel in the cylinder 1 from the exhaust port of each cylinder 1 to the outside. An exhaust manifold 42 and an exhaust purification three-way catalyst 41 are disposed on the exhaust passage 4.

  The internal combustion engine is often accompanied by an external EGR (exhaust gas recirculation) device 2. The external EGR device 2 of the internal combustion engine in the present embodiment realizes a so-called high-pressure loop EGR, and an EGR passage 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. 21, an EGR cooler 22 provided on the EGR passage 21, and an EGR valve 23 that opens and closes the EGR passage 21 and controls the flow rate of EGR gas flowing through the EGR passage 21.

  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. Therefore, the EGR gas to be distributed to all the cylinders 1 once flows into the surge tank 33 and then travels to each cylinder 1 via the intake manifold 34. The EGR cooler 22 is a heat exchanger that lowers the temperature of the EGR gas by exchanging high heat of the EGR gas that circulates through the EGR passage 21 with cooling water (coolant) of the internal combustion engine.

  FIG. 2 shows an example of a drive system provided in the vehicle. This drive system includes a torque converter 7 and automatic transmissions 8 and 9. In particular, in the present embodiment, a forward / reverse switching device 8 using a planetary gear mechanism and a belt-type CVT (Continuously Variable Transmission) 9 which is a type of continuously variable transmission are adopted as components of the automatic transmissions 8 and 9. doing.

  The rotational torque output from the internal combustion engine is input from the crankshaft of the internal combustion engine to the pump impeller 71 on the input side of the torque converter 7 and 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 a shift in the CVT 9. The rotation of the driven shaft 95 is transmitted to the output gear 101. The output gear 101 meshes with the ring gear 102 of the differential device, and rotates the axle 103 and the drive wheels (not shown) via the differential device.

  The torque converter 7 includes a lockup mechanism. The lock-up mechanism is known in this field, and a lock-up clutch 73 that fastens the input side and the output side of the torque converter 7 so as not to rotate relative to each other, and an operation for switching the connection of the lock-up clutch 73. A lock-up solenoid valve (not shown) for controlling the hydraulic pressure (hydraulic pressure) is used as an element. The lockup solenoid valve is a flow rate control valve that receives a control signal o and changes its opening.

  In the forward / reverse switching device 8, the sun gear 81 communicates with the turbine runner 72 on the output side of the torque converter 7, and the ring gear 82 communicates with the drive shaft 94. Between the planetary carrier 83 that supports the planetary gear 831 and the transmission case, a forward brake 84 that is a hydraulic clutch that can be connected and disconnected is interposed. Further, a reverse clutch 85, which is a hydraulic clutch capable of switching connection / disconnection, is also interposed between the planetary carrier 83 and the sun gear 81 (or the output side of the torque converter 7).

  In the D range of the traveling range, the forward brake 84 is engaged and the reverse clutch 85 is disconnected. As a result, the rotation of the output shaft of the torque converter 7 is reversed and decelerated and transmitted to the drive shaft 94 for forward travel. In turn, in the R range, the reverse clutch 85 is engaged and the forward brake 84 is disconnected. 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 perform reverse travel. A solenoid valve (not shown) that controls the hydraulic pressure for driving the forward brake 84 or the reverse clutch 85 to connect / disconnect is a flow rate control valve that receives a control signal m and changes its opening.

  In the N range and P range, which are non-traveling ranges, both the forward brake 84 and the reverse clutch 85 are disconnected.

  The CVT 9 includes a driving pulley 91 and a driven pulley 92, and a belt 93 wound around the pulleys 91 and 92 as elements. The drive pulley 91 is disposed behind the movable sheave 912, a fixed sheave 911 fixed to the drive shaft 94, a movable sheave 912 supported on the drive shaft 91 via a roller spline so as to be displaceable in the axial direction. A hydraulic servo 913 is provided, and the gear ratio can be changed steplessly by operating the hydraulic servo 913 and displacing the movable sheave 912. The driven pulley 92 is disposed on the back of the movable sheave 922, a fixed sheave 921 fixed to the driven shaft 95, a movable sheave 922 supported on the driven shaft 95 via a roller spline so as to be axially displaceable. A hydraulic servo 923 is provided, and a belt thrust necessary for torque transmission is applied by operating the hydraulic servo 923 and displacing the movable sheave 922.

  FIG. 3 shows the configuration of the air conditioner 5 that controls the air conditioning in the vehicle interior. The air conditioner 5 includes a compressor 51 that compresses the refrigerant, a capacitor 52 that radiates and liquefies the compressed refrigerant, a capacitor fan 53 that forcibly cools the capacitor 52, and a gaseous refrigerant that has not been liquefied. A receiver 54 for separating the refrigerant from the liquefied refrigerant, an expansion valve 55 for ejecting the liquefied refrigerant, an evaporator 56 for receiving the ejected and vaporized refrigerant and exchanging heat with the air in the room, and cooling water for the high-temperature internal combustion engine. A heater core 59 that exchanges heat with the air in the receiving room, a blower fan 57 that sucks and discharges the indoor air toward the evaporator 56, and sends the air into the room again. The air that is discharged from the blower fan 57 and passes through the evaporator 56 Air mixer to adjust how much air is blown to the heater core 59 And the path 50 to the element. The compressor 51, the condenser 52, the receiver 54, the expansion valve 55, and the evaporator 56 are connected by a refrigerant flow path that loops.

  The compressor 51 rotates in response to transmission of rotational torque from the crankshaft of the internal combustion engine. Between the crankshaft and the compressor 51, there is a magnet clutch 58 capable of switching between connection and disconnection.

  The condenser 52 is disposed at a portion where the traveling wind hits in the engine room of the vehicle, and is cooled by the traveling wind blown into the engine room during traveling of the vehicle regardless of whether the condenser fan 53 is rotated. Behind the condenser 52 is a radiator 7 for radiating the cooling water of the internal combustion engine. The radiator 7 is also cooled by the traveling wind.

  The condenser fan 53 is for forcibly cooling the condenser 52 by air. In this embodiment, the condenser fan 53 is also used as a radiator fan for forcibly cooling the radiator 7 by air. The condenser fan 53 is located behind the radiator 7 and sucks air from the front and discharges it to the rear. The condenser fan 53 functions to take outside air into the engine room from outside the vehicle via the front grille.

  When the air discharged from the blower fan 57 passes through the evaporator 56, it obtains cold heat from the refrigerant (heat is taken away by the refrigerant) and decreases in temperature. At the same time, the water vapor contained in the air condenses and adheres to the evaporator 56, and the humidity decreases. The evaporator 56 plays a role not only for cooling the room temperature in the summer but also for reducing the fog on the window glass of the vehicle by reducing the room humidity in the winter.

  The air mix damper 50 adjusts the ratio of the amount of air that passes through the heater core 59 and goes into the room, and the amount of air that goes around the heater core 59 and goes into the room among the air that has passed through the evaporator 56. The air mix damper 50 can adjust the temperature of the air blown into the room.

  FIG. 4 shows an electric circuit 6 that energizes the magnet clutch 58, the fan motor 531 that drives the condenser fan 53, and the fan motor 571 that drives the blower fan 57. The power source is an in-vehicle battery 61 and / or a generator (alternator or motor generator) 62 that generates electric power by receiving transmission of rotational torque from the crankshaft of the internal combustion engine.

  When the relay switch 63 on the circuit 6 is turned ON, the magnet clutch 58 is energized and fastened, and the compressor 51 rotates to enter an operating state in which the refrigerant is compressed. When the relay switch 64 is turned on, the fan motor 531 is energized and the condenser fan 53 rotates. When the relay switch 65 is turned on, the fan motor 571 is energized and the blower fan 57 rotates. Incidentally, the relays 63, 64, 65 may be replaced with semiconductor switching elements such as power transistors and MOSFETs.

  An ECU (Electronic Control Unit) 0 serving as 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 input interface includes a vehicle speed signal a output from a vehicle speed sensor that detects the actual vehicle speed of the vehicle, a crank angle signal b output from an engine rotation sensor that detects the rotation angle and engine speed of the crankshaft, and depression of an accelerator pedal. Accelerator opening signal c output from a sensor that detects the amount or the opening of the throttle valve 32 as an accelerator opening (so-called load required for the internal combustion engine), the temperature of the intake air in the intake passage 3 (particularly, the surge tank 33) And an intake air temperature / intake pressure signal d output from an intake air temperature / intake pressure sensor for detecting pressure, an outside air temperature signal e output from an air temperature sensor for detecting the temperature of outside air, and a water temperature sensor for detecting a cooling water temperature of the internal combustion engine The coolant temperature signal f output from the sensor (or the shift position switch) Shift range signal g outputted from the switch), the acceleration signal h such that acceleration or vehicle of a vehicle is outputted from the acceleration sensor for detecting an inclination of a road surface being located is inputted.

  From the output interface, the ignition signal i for the igniter of the spark plug 12, the fuel injection signal j for the injector 11, the opening operation signal k for the throttle valve 32, and the opening operation signal l for the EGR valve 23. An opening degree control signal m for the solenoid valve for switching connection / disconnection of the forward brake 84 or the reverse clutch 85, a gear ratio control signal n for CVT9, and a lockup solenoid valve for switching connection / disconnection of the lockup clutch 73. In contrast, an opening control signal o, an ON (energization) signal p to the relay switch 63, an ON signal q to the relay switch 64, an ON signal r to the relay switch 65, and the like are output.

  The processor of the ECU 0 interprets and executes a program stored in the memory in advance, calculates operation parameters, and controls the operation of the internal combustion engine. The ECU 0 acquires various information a, b, c, d, e, f, g, and h necessary for operation control of the internal combustion engine via the input interface, knows the engine speed, and is filled in the cylinder 1. The intake air amount (new air amount and EGR gas amount) is estimated. Based on the engine speed, the intake air amount, etc., the required fuel injection amount, fuel injection timing (including the number of times of fuel injection for one combustion), fuel injection pressure, ignition timing, required EGR rate (or EGR rate) Amount), CVT9 gear ratio, and the like. The ECU 0 applies various control signals i, j, k, l, m, n, o, p, q, r corresponding to the operation parameters via the output interface.

  ECU0 of this embodiment performs control which changes the gear ratio of CVT9 to a low gear side, when it senses that the vehicle exists on the uphill road now. The gradient of the road surface where the vehicle is located can be estimated based on, for example, the vehicle speed detected via the vehicle speed sensor and the vehicle acceleration detected via the acceleration sensor. The ECU 0 determines that the vehicle is traveling on an uphill road when the estimated magnitude of the upward gradient exceeds a predetermined determination threshold value. Of course, the estimation method of the road gradient is not limited to this, and other known methods may be used.

  FIG. 5 shows a shift diagram when the ECU 0 controls the CVT 9. The shift diagram represents the target input rotation speed (rotation speed of the turbine 72) corresponding to the vehicle speed and the accelerator opening, and the transmission ratio (reduction ratio) of the CVT 9 according to the vehicle speed and the required load (accelerator opening). Is specified. In FIG. 5, the shift line at full load operation with an accelerator opening of 100% is indicated by a broken line, the shift line at idle operation or fuel cut with an accelerator opening of 0% is indicated by a chain line, and the accelerator opening is both The shift lines at the time of partial load operation that are in the middle are drawn with solid lines. The gear ratio takes a value between the low gear side limit L and the high gear side limit H that the CVT 9 can implement in hardware.

  The ECU 0, which senses that the vehicle exists on the uphill road, raises the target input rotation speed of the CVT 9 from the normal time (such as when running on a flat road, or not on the uphill road), thereby reducing the transmission ratio of the CVT 9 to a low gear. (Ie, increasing the reduction ratio of the CVT 9) and increasing the driving torque transmitted to the axle 103 to ensure the climbing performance of the vehicle. For example, the shift line in the partial load operation is shifted upward from a normal time indicated by a thin solid line in FIG. 5 to a line drawn by a thick solid line.

  Furthermore, when the ECU 0 of the present embodiment senses that the vehicle is currently on an uphill road, it performs correction control for increasing the output of the internal combustion engine described below.

  (I) Enlargement of the opening degree of the throttle valve 32; FIG. 6 shows the relationship between the depression amount of the accelerator pedal and the opening degree of the electronic throttle valve 32. In FIG. 6, the input / output characteristics when the vehicle is located on the uphill road are drawn by a thick solid line, and the input / output characteristics when the vehicle is not so are drawn by a thin solid line. The opening of the electronic throttle valve 32 increases and decreases non-linearly during normal times, but increases and decreases linearly when traveling uphill, with respect to changes in the amount of depression of the accelerator pedal. Thereby, especially in the partial load region, the opening degree of the throttle valve 32 with respect to the same depression amount of the accelerator pedal becomes larger when traveling uphill. An increase in the opening of the throttle valve 32 leads to a reduction in pumping loss of the internal combustion engine and an increase in the intake air amount and the fuel injection amount charged in the cylinder 1 and thus the output of the internal combustion engine is enhanced.

  (Ii) Reduction of EGR; the EGR rate required for intake air varies depending on the operation region [engine speed, required load (or intake pressure, intake air amount)] of the internal combustion engine. FIG. 7 shows the relationship between the required load and the required EGR rate. In FIG. 7, the required EGR rate when the vehicle is located on the uphill road is drawn with a thick solid line, and the required EGR rate when the vehicle is not so is drawn with a thin solid line. Basically, the required EGR rate is highest in a region where the required load is medium, decreases as the required load decreases from the region, and decreases as the accelerator opening increases from the region. Since the EGR is not performed in the idling operation, a low load range close to this, and the full load range, the target EGR rate and the EGR valve 23 opening are zero. When traveling uphill, the required EGR rate is lowered than normal, and / or the range of the operation region in which EGR is executed (the operation region where the required EGR rate is not 0) is reduced. Decreasing the EGR rate of intake means increasing the amount of fresh air (oxygen) charged into the cylinder 1 and the amount of fuel injection. Accordingly, the output of the internal combustion engine is enhanced.

  (Iii) Increase in the average output of the condenser fan 53: When traveling uphill, the output of the condenser fan (radiator fan) 53 is increased more than normal, and the amount of outside air introduced into the engine room from outside the vehicle is increased. Then, the temperature of each part of the engine room and the internal combustion engine is lowered, and consequently the temperature of the intake air flowing through the intake passage 3 is lowered. As a result, the charging efficiency of the intake air is improved, the intake air amount and the fuel injection amount that are charged into the cylinder 1 are increased, and the output of the internal combustion engine is enhanced. In addition, during the operation of the air conditioner 5, the cooling performance of the refrigerant in the condenser 52 is improved, the refrigerant pressure is reduced, and the load of the compressor 51 on the internal combustion engine is reduced. The supplied drive torque is increased. The average output of the condenser fan 53 can be controlled by changing the ratio of the ON time during which the fan motor 531 that drives the condenser fan 53 is energized and the OFF time during which it is not energized. Alternatively, it can be controlled by changing the magnitude of the applied current or applied voltage to the fan motor 531. Note that the output of the condenser fan 53 during climbing may be adjusted according to the vehicle speed, the intake air temperature, and the like at that time. That is, the higher the vehicle speed, the stronger the traveling wind blown into the engine room, and the engine room is naturally air-cooled, so the output of the condenser fan 53 is reduced to save power consumption. Similarly, the output of the condenser fan 53 may be lowered as the intake air temperature is lower.

  (Iv) Enriching the air-fuel ratio: When traveling uphill, the fuel injection amount is increased from that during normal times to enrich the air-fuel ratio of the air-fuel mixture.

  In the correction control (i) to (iv) described above, there has been a request for acceleration in which the amount of depression of the accelerator pedal is greater than a predetermined value and / or the amount of increase in the amount of depression of the accelerator pedal per unit time is greater than a predetermined value. It shall be carried out from time to time. When there is no acceleration request, the correction control need not be performed.

  Moreover, not all of (i) to (iv) are performed when traveling uphill. The priorities in consideration of the practical fuel consumption performance of the vehicle are in the order of (iii), (ii), (i), (iv). Therefore, when it is detected that the vehicle has reached the uphill road, (iii) is first performed. Then, when the required load on the uphill road becomes larger than a predetermined value, or when the required load on the uphill road continues for a predetermined time or longer, (ii), (iv) and (i) are sequentially performed. To do. In other words, (iii) and (ii) are used together while the required load is relatively small or the duration is relatively short, and (iv) is added if the required load increases or the duration becomes long To implement. Further, (i) is additionally performed for a kite whose required load has increased or whose duration has become longer.

  In this embodiment, when it is detected that the vehicle is on an uphill road and the accelerator pedal is depressed by the driver, the transmission ratio of the transmission 9 interposed between the internal combustion engine and the axle 103 is determined. Is set closer to the low gear than when the vehicle is on a flat road, and the opening of the throttle valve 32 for the same accelerator pedal depression amount is compared with that when the vehicle is on a flat road. The vehicular control device 0 is characterized in that it opens wide or the average output of the fan 53 for sucking outside air into the engine room is increased as compared with the case where the vehicle is on a flat road.

  According to the present embodiment, since the output control of the internal combustion engine is also executed in cooperation with the transmission ratio control of the transmission 9 on the uphill road, the uphill running performance of the vehicle is improved, and the practical fuel consumption and the practical running performance are Is balanced. The driver is less likely to feel insufficient driving torque. The control of this embodiment can be implemented at low cost without the addition of new hardware.

  The present invention is not limited to the embodiment described in detail above. The specific configuration of each part can be variously modified without departing from the spirit of the present invention.

  The present invention can be applied to control of a vehicle equipped with an internal combustion engine.

0 ... Control unit (ECU)
11 ... Injector 23 ... EGR valve 32 ... Throttle valve 53 ... Fan (capacitor fan and radiator fan)
7, 8, 9 ... Transmission (torque converter, forward / reverse switching device, CVT)

Claims (1)

When it is detected that the vehicle is on an uphill road and the accelerator pedal is depressed by the driver,
While setting the transmission gear ratio of the transmission interposed between the internal combustion engine and the axle closer to the low gear compared to the case where the vehicle is on a flat road ,
A control device for a vehicle, characterized in that an average output of a fan for sucking outside air into an engine room is increased as compared with a case where the vehicle exists on a flat road.

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