JP2016031313A - Vehicle control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily detect a deformation of a vehicle tire.SOLUTION: It is determined whether a tire of a vehicle deforms on the basis of whether a cycle of a fluctuation in a rotational speed of an internal combustion engine mounted in the vehicle generally matches a cycle of rotation of the tire.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a control device for a vehicle equipped with an internal combustion engine.

  By repeatedly measuring the time required for the crankshaft, which is the output shaft of the internal combustion engine, to rotate by a predetermined angle, the amount of decrease in rotational speed is obtained, and when this amount of decrease exceeds a determination threshold value, misfire occurs in the cylinder. There are known misfire determination methods for determining that the occurrence has occurred (see, for example, the following patent document).

JP 2012-077700 A

  When the tire slides with respect to the road surface in a state where the rotation of the tire is locked by sudden braking of the vehicle, only the portion in contact with the road surface of the tire is worn. Also, the tire undergoes plastic deformation due to parking for an extremely long period (for example, several months to one year or more).

  When the tire deforms irreversibly, a fluctuation (vibration) like swell that matches the rotation cycle of the tire occurs in the rotation speed of the internal combustion engine. Then, this fluctuation in the rotational speed can adversely affect the determination of the presence or absence of misfire in the cylinder of the internal combustion engine. That is, there is a concern that the amount of decrease in the rotational speed of the internal combustion engine instantaneously exceeds the determination threshold value even though no misfire has occurred, and it is erroneously determined that misfire has occurred.

  An object of the present invention made in view of the above is to easily detect deformation of a tire of a vehicle.

  In order to solve the above-described problems, in the present invention, the deformation of the vehicle tire is determined based on whether or not the cycle of fluctuations in the rotational speed of the internal combustion engine mounted on the vehicle substantially coincides with the cycle of rotation of the vehicle tire. A vehicle control device for determining the presence or absence of the vehicle is configured.

  According to the present invention, it is possible to easily detect deformation of a vehicle tire.

The figure which shows the whole structure of the internal combustion engine for vehicles in one Embodiment of this invention. The figure which shows the structure of the drive system of the vehicle in the embodiment. The timing diagram which illustrates transition of the engine speed in case a tire has changed. The flowchart which shows the example of a procedure of the process performed when the control apparatus of the embodiment determines the presence or absence of a deformation | transformation of a tire.

  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 four-stroke 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 external EGR (Exhaust Gas Recirculation) device 2 realizes a so-called high pressure loop EGR, and an external EGR passage 21 that connects 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. The EGR cooler 22 provided on the EGR passage 21 and the EGR valve 23 that opens and closes the EGR passage 21 and controls the flow rate of the EGR gas flowing through the EGR passage 21 are used as elements. The inlet of the EGR passage 21 is connected to the exhaust manifold 42 in the exhaust passage 4 or a predetermined location downstream thereof. The outlet of the EGR passage 21 is connected to a predetermined location downstream of the throttle valve 32 in the intake passage 3, specifically to a surge tank 33.

  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, which is the output shaft 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 a drive wheel tire (not shown) fixed to the axle 103 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 l and changes its opening.

  In a vehicle equipped with CVT 9, when the vehicle speed is a predetermined value (for example, 10 km / h) or more, the torque converter 7 is almost always locked up. When the vehicle speed is equal to or lower than the predetermined value, the lockup of the torque converter 7 is released. During lockup, the lockup clutch 73 is pressed against the torque converter cover 74 and rotates together with the torque converter cover 74. The engine torque input to the input side (drive plate) of the torque converter 7 at the time of lock-up is output from the torque converter cover 74 via the lock-up clutch 73 and thus to the forward / reverse switching device 8. Communicated directly to. At the time of lockup, the speed ratio, which is the ratio of the output side rotational speed of the torque converter 7 to the input side rotational speed, is 1.

  In turn, the lock-up clutch 73 is separated from the torque converter cover 74 at the time of non-lock-up. At the time of non-lock-up, the engine torque input to the input side of the torque converter 7 is transmitted from the torque converter cover 74 to the pump impeller 71 and the turbine 72 and is transmitted to the forward / reverse switching device 8. At the time of non-lock-up, the speed ratio of the torque converter 7 becomes smaller or larger than 1 depending on the driving state.

  In the forward / reverse switching device 8, the sun gear 81 communicates with the turbine runner 72, 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 displaceable in the axial direction. 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.

  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 degree signal c output from a sensor that detects the amount or opening degree of the throttle valve 32 as an accelerator opening degree (so-called load required for the internal combustion engine), oxygen concentration or air-fuel ratio of exhaust gas flowing through the exhaust passage 4 is detected. An air-fuel ratio signal d output from an air-fuel ratio sensor, an intake air temperature / intake pressure signal e output from a temperature / pressure sensor that detects intake air temperature and intake pressure in the intake passage 3 (particularly, the surge tank 33), an internal combustion engine A coolant temperature signal f output from a coolant temperature sensor that detects the coolant temperature of the engine, and a sensor for obtaining the shift lever range. Sa (or, a shift position switch) shift range signal g output from the cam angle signal h or the like to be output from the cam angle sensor at a plurality of cam angle of the intake camshaft or the exhaust camshaft is input.

  From the output interface, an ignition signal i for the igniter of the spark plug 12, a fuel injection signal j for the injector 11, an opening operation signal k for the throttle valve 32, and a lock for connection / disconnection switching of the lockup clutch 73. The opening degree control signal 1 for the up solenoid valve, the opening degree control signal m for the solenoid valve for switching connection / disconnection of the forward brake 84 or the reverse clutch 85, the transmission ratio control signal n for the CVT 9, and the EGR valve 23. In response to this, an opening operation signal o or the like is 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. Estimate the intake volume. Based on the engine speed and 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, required EGR rate (or EGR amount), Various operation parameters such as ignition timing, whether or not to lock up the torque converter 7 and the gear ratio of the automatic transmissions 8 and 9 are determined. The ECU 0 applies various control signals i, j, k, l, m, n, and o corresponding to the operation parameters via the output interface.

  In addition, the ECU 0 measures the rotational speed per predetermined rotational angle of the crankshaft of the internal combustion engine, and compares the amount of change in the rotational speed, that is, the amount of decrease with the determination threshold value, so that misfire has occurred in the cylinder 1 Determine whether or not.

  Hereinafter, a misfire determination method performed by the ECU 0 of the present embodiment will be described in detail. The ECU 0 repeatedly measures the time required for the crankshaft to rotate at a predetermined rotation angle, for example, 30 ° CA (crank angle), via the engine rotation sensor, and the required time previously measured from the required time measured this time. By subtracting the time, a value serving as an index of the amount of decrease in the rotation speed every 30 ° CA, in other words, a change amount (difference) in the required time of 30 ° CA is obtained.

  A positive change in the required time of 30 ° CA means that the rotational speed of the internal combustion engine tends to decelerate, and a negative value means that the rotational speed of the internal combustion engine tends to accelerate. To do. Usually, the internal combustion engine is accelerated during the expansion stroke of one of the cylinders 1 and decelerated during the other strokes. When a misfire occurs in a cylinder 1, acceleration is not performed in the expansion stroke of the cylinder 1, and thus the value of the change in required time of 30 ° CA increases. Therefore, the ECU 0 uses the amount of change in the required time of 30 ° CA as an index value and compares it with a determination threshold value. If the former index value exceeds the latter determination threshold value, there is a possibility that a misfire has occurred. Is determined.

  However, when irreversible deformation such as local wear or plastic deformation occurs in the tire of the vehicle, the rotational speed of the tire fluctuates (vibrates) like a swell, and the internal combustion engine connected to the axle is The rotational speed also varies like undulations as well. This pattern is illustrated in FIG. FIG. 3 shows the transition of the engine speed during steady running when the internal combustion engine is not particularly accelerated or decelerated.

  If the engine rotation speed fluctuates due to the deformation of the tire, the required time of 30 ° CA and the amount of change thereof will be wavy. Then, the swell may increase the maximum value of the change amount of the required time of 30 ° CA, and may exceed the determination threshold. In other words, it is erroneously determined that the cylinder 1 has misfired even though no misfire has occurred in the cylinder 1.

  Therefore, in the present embodiment, whether or not the tire of the vehicle is deformed is determined, and when it is determined that the tire is deformed, a determination threshold for determining the presence or absence of misfire is set as compared to the case where the tire is not deformed. It is supposed to be raised.

  The cycle T of the fluctuation of the engine speed when the tire is deformed, and hence the cycle T of the fluctuation amount of the required time of 30 ° CA is substantially equal to the cycle of one revolution of the deformed tire. Therefore, it is possible to determine whether or not the tire is deformed based on whether or not the cycle T of the fluctuation of the engine speed substantially matches the cycle of rotation of the tire.

  FIG. 4 shows a procedure example of processing executed by the ECU 0 according to the present embodiment in accordance with a program. The ECU 0 investigates whether or not the tire is deformed under a situation where the vehicle is traveling steadily. Specifically, when the current load of the internal combustion engine, engine speed, air-fuel ratio, etc. are within predetermined ranges for a predetermined period of time (step S1), the vehicle is considered to be running steady. . And while measuring the cycle of the fluctuation | variation of an engine speed (step S2), the cycle of one rotation of a tire is measured (step S3), and both are compared (step S4).

  In step S2, as shown in FIG. 3, the time difference T from when the extreme value (maximum value or minimum value) of the engine speed appears until the next extreme value appears is measured. Here, the engine speed should be a time-series moving average of the required time for every 30 ° CA (or add up the required time for the most recent past crank angle (for example, 360 ° CA)). The variation between the strokes of the cylinder 1 obtained by the above is suppressed. It should be noted that the amount of change in the required time of 30 ° CA may be referred to instead of the engine speed, and the time difference T from when an extreme value appears to the change amount until the next extreme value appears may be measured. . In this case, the amount of change in the required time of 30 ° CA is also assumed to suppress fluctuations between the strokes of the cylinder 1 by taking a moving average in advance.

  In step S3, the tire rotation cycle is estimated based on the tire size (previously stored in the memory of the ECU 0 as a constant), the current engine speed, and the gear ratio of the drive system. However, if a rotation sensor for detecting the rotation speed of the axle or the tire is mounted on the vehicle, the rotation period of the tire can be directly measured via the sensor.

  Thus, the ECU 0 determines that the engine rotation speed fluctuation period is substantially equal to the tire rotation period, in other words, the absolute value of the difference between the engine rotation speed fluctuation period and the tire rotation period is equal to or less than a predetermined value. (Step S4), it is determined that the tire is deformed, and a message to that effect is output (step S5). In step S5, information indicating that the tire is deformed (which may be a flag or a diagnosis code) is stored in a memory and held.

  Further, in step S5, it may be notified that the tire is deformed in a manner appealing to the driver's or passenger's sight or hearing, and the tire may be exchanged. For example, a warning light installed in a cockpit of a vehicle may be turned on, a warning may be displayed on a display, or a warning sound or sound may be output via a buzzer or a speaker.

  Further, the ECU 0 that has determined that the tire is deformed determines the determination threshold value to be compared with the amount of change in the required time of 30 ° CA in the subsequent misfire determination before determining that the tire is deformed. Is raised to a higher value (step S6). Thereby, even if the undulation resulting from the deformation of the tire is added to the amount of change in the required time of 30 ° CA, the amount of change is less likely to exceed the determination threshold, and the risk of misjudgment of misfire is reduced.

  In the present embodiment, a vehicle that determines whether or not a vehicle tire is deformed based on whether or not the cycle of fluctuations in the rotational speed of an internal combustion engine mounted on the vehicle substantially coincides with the cycle of rotation of a vehicle tire. A control device 0 was configured. According to the present embodiment, it is possible to easily detect deformation of a vehicle tire. In addition, since the deformed tire has a large rolling resistance and becomes a factor of deteriorating the fuel efficiency of the vehicle, it is possible to notify the driver or the passenger after detecting this accurately and to prompt early tire replacement.

  In the present embodiment, whether or not misfiring has occurred in the cylinder 1 of the internal combustion engine is determined based on whether or not the amount of decrease in the rotational speed per predetermined rotational angle of the internal combustion engine mounted on the vehicle exceeds the determination threshold. Thus, the vehicle control device 0 is configured to raise the determination threshold value when the deformation of the vehicle tire is detected, as compared with the case where the deformation of the vehicle tire is not detected. According to this embodiment, it is possible to avoid misjudgment of misfire due to the influence of the swell of the rotational speed of the internal combustion engine due to deformation of the tire, and the judgment accuracy of the presence or absence of misfire is further improved.

  The present invention is not limited to the embodiment described in detail above. Various modifications can be made to the specific configuration of each part, processing procedure, and the like 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)
DESCRIPTION OF SYMBOLS 1 ... Cylinder 7 ... Torque converter 8 ... Transmission (forward / reverse switching device, CVT)
103 ... Axle

Claims (1)

A vehicle control apparatus that determines whether or not a tire of a vehicle is deformed based on whether or not a cycle of fluctuation in rotational speed of an internal combustion engine mounted on the vehicle substantially coincides with a cycle of rotation of a tire of the vehicle.

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