Abstract:
A system and a method of controlling vehicle starting may include a wheel speed sensor detecting a speed of at least one wheel among wheels of the vehicle, a vehicle speed detector detecting a vehicle speed, an acceleration detector detecting a vehicle acceleration, a vertical acceleration sensor detecting a vertical acceleration of the vehicle, a wheel torque detector calculating a wheel torque, an ambient temperature sensor detecting an ambient temperature, and a controller. The controller may calculate a wheel slip amount based on the speed of at least one wheel, the vehicle speed and the vehicle acceleration, determine whether a wheel slip occurs by comparing the wheel slip amount with a first predetermined wheel slip amount, determine a road state based on the ambient temperature and the vertical acceleration of the vehicle if the wheel slip occurs, and perform a starting control according to the road state.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    The present application claims priority of Korean Patent Application Number 10-2013-0081597 filed on Jul. 11, 2013, the entire contents of which application are incorporated herein for all purposes by this reference. 
       BACKGROUND OF INVENTION 
       [0002]    1. Field of Invention 
         [0003]    The present invention relates to a system and a method of controlling starting of a vehicle. More particularly, the present invention relates to a system and a method of controlling starting of a vehicle which perform a starting control of the vehicle according to a road state. 
         [0004]    2. Description of Related Art 
         [0005]    Generally, a starting control means a control of an engine and a transmission which is performed when the vehicle begins to run in a stopped state. Serious problems do not occur if the vehicle is started on a normal road, but slip and locking of a wheel may often occur if the vehicle is started on a low-friction road, an icy road, or a rough road. 
         [0006]    According to a conventional starting control, a transmission is controlled at a predetermined shift-speed by using a predetermined shift pattern and an engine torque is controlled by using a predetermined torque filter regardless of a road state. Therefore, if a conventional vehicle is started on the low-friction road, the icy road, or the rough road, a driver changes a shift mode to a manual shift mode and manipulates the shift manually, activates a snow mode, or activates or deactivates a traction control. In this case, since the driver must know a suitable manipulation to each road state, an unskilled driver is hard to start the vehicle at a specific road state. In addition, if the driver manipulates incorrectly to each road state, accidents could happen. Therefore, it is necessary to differentiate a starting control according to a road state. 
         [0007]    The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art. 
       SUMMARY OF INVENTION 
       [0008]    The present invention has been made in an effort to provide a system and a method of controlling starting of a vehicle having advantages of driving the vehicle safely and conveniently by performing a suitable starting control according to a road state. 
         [0009]    A system of controlling starting of a vehicle according to various aspects of the present invention may include: a wheel speed sensor detecting a speed of at least one wheel among wheels of the vehicle; a vehicle speed detector detecting a vehicle speed; an acceleration detector detecting a vehicle acceleration; a vertical acceleration sensor detecting a vertical acceleration of the vehicle; a wheel torque detector calculating a wheel torque; an ambient temperature sensor detecting an ambient temperature; and a controller calculating a wheel slip amount based on the speed of at least one wheel, the vehicle speed and the vehicle acceleration, determining whether a wheel slip occurs by comparing the wheel slip amount with a first predetermined wheel slip amount, determining a road state based on the ambient temperature and the vertical acceleration of the vehicle if the wheel slip occurs, and performing a starting control according to the road state. 
         [0010]    The first predetermined wheel slip amount may be set according to the wheel torque. The controller may perform the starting control according to an icy road if the road state is the icy road. The controller may determine that the road state is the icy road if the wheel slip amount is greater than or equal to a second predetermined wheel slip amount and the ambient temperature is lower than or equal to a predetermined temperature in a state that the wheel slip occurs. The second predetermined wheel slip amount may be set according to the wheel torque. 
         [0011]    The controller may perform the starting control according to a rough road or an unpaved road if the road state is the rough road or the unpaved road. The controller may determine that the road state is the rough road or the unpaved road if the road state is not the icy road, and the number of times an absolute value of third derivative of the vertical acceleration of the vehicle is greater than a predetermined value is greater than or equal to a predetermined number during a predetermined time in a state that the wheel slip occurs. The controller may perform the starting control according to a slippery road if the road state is not the icy road nor the rough road or the unpaved road in a state that the wheel slip occurs. 
         [0012]    A method of controlling starting of a vehicle according to various aspects of the present invention may include: detecting data for a starting control; calculating a wheel slip amount based on the data; determining whether a wheel slip occurs based on the wheel slip amount; determining whether a road state is an icy road if the wheel slip occurs; and performing the starting control according to the icy road if the road state is the icy road. 
         [0013]    It may be determined that the wheel slip occurs if the wheel slip amount is greater than a first predetermined wheel slip amount. The first predetermined wheel slip amount may be set according to a wheel torque. 
         [0014]    It may be determined that the road state is the icy road if the wheel slip amount is greater than or equal to a second predetermined wheel slip amount and an ambient temperature is lower than or equal to a predetermined temperature in a state that the wheel slip occurs. The second predetermined wheel slip amount may be set according to a wheel torque. 
         [0015]    A transmission may be controlled using a normal shift pattern, a shift-speed may be controlled to be higher than or equal to a second forward speed, and an engine torque may be controlled using a first torque filter which is smaller than a normal torque filter in the starting control according to the icy road. 
         [0016]    If the road state is not the icy road, the method may further include: determining whether the road state is a rough road or an unpaved road; and performing the starting control according to the rough road or the unpaved road if the road state is the rough road or the unpaved road. It may be determined that the road state is the rough road or the unpaved road if the road state is not the icy road, and the number of times an absolute value of third derivative of the vertical acceleration of the vehicle is greater than a predetermined value is greater than or equal to a predetermined number during a predetermined time in a state that the wheel slip occurs. 
         [0017]    A transmission may be controlled using a hold shift pattern, a shift-speed may be controlled to be higher than or equal to a second forward speed, and an engine torque may be controlled using a first torque filter smaller than a normal torque filter in the starting control according to the rough road or the unpaved road. 
         [0018]    If the road state is not the rough road or the unpaved road, the method may further include performing the starting control according to a slippery road. A transmission may be controlled using a hold shift pattern, a shift-speed may be controlled to be a first forward speed, and an engine torque may be controlled using a second torque filter that is larger than a normal torque filter and is smaller than a first torque filter in the starting control according to the slippery road. 
         [0019]    The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description, which together serve to explain certain principles of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]      FIG. 1  is a block diagram of a system of controlling starting of a vehicle according to the present invention. 
           [0021]      FIG. 2  is a flowchart of a method of controlling starting of a vehicle according to the present invention. 
           [0022]      FIG. 3  is a table of the first predetermined wheel slip amount and the second predetermined wheel slip amount set according to a wheel torque. 
           [0023]      FIG. 4  is a table showing a starting control according to the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0024]    Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims. 
         [0025]      FIG. 1  is a block diagram of a system of controlling starting of a vehicle according to various embodiments of the present invention. As shown in  FIG. 1 , a system of controlling starting of a vehicle includes a data detector  10 , a controller  20 , an engine  30  and a transmission  40 . 
         [0026]    The data detector  10  detects data for a starting control of the vehicle, and the data detected by the data detector  10  is transmitted to the controller  20 . The data detector  10  includes a wheel speed sensor  11 , a vehicle speed detector  12 , an acceleration detector  13 , a vertical acceleration sensor  14 , a wheel torque detector  15  and an ambient temperature sensor  16 . 
         [0027]    The wheel speed sensor  11  is mounted at each wheel of the vehicle and detects a speed of each wheel. In this specification, the wheel speed may be a value converted into a vehicle speed. That is, the wheel speed may be defined by multiplying the speed of each wheel and a radius of each wheel. In the conventional vehicle, the wheel speed sensors  11  are mounted respectively at a front left wheel, a front right wheel, a rear left wheel, and a rear right wheel. Herein, a rotation speed of the front left wheel is denoted by a WheelSpeed FL , a rotation speed of the front right wheel is denoted by a WheelSpeed FR , a rotation speed of the rear left wheel is denoted by a WheelSpeed RL  and a rotation speed of the rear right wheel is denoted by a WheelSpeed RR . 
         [0028]    The vehicle speed detector  12  calculates the vehicle speed from the wheel speed detected by the wheel speed sensor  11 . Herein, the vehicle speed may be defined by an average of a plurality of wheel speeds. That is, the vehicle speed VS is calculated from the below equation in a case of the conventional vehicle. 
         [0000]    
       
         
           
             
               
                 
                   VS 
                   = 
                   
                     
                       ( 
                       
                         
                           
                             
                               
                                 WheelSpeed 
                                 FL 
                               
                               + 
                               
                                 WheelSpeed 
                                 FR 
                               
                               + 
                             
                           
                         
                         
                           
                             
                               
                                 WheelSpeed 
                                 RL 
                               
                               + 
                               
                                 WheelSpeed 
                                 RR 
                               
                             
                           
                         
                       
                       ) 
                     
                     4 
                   
                 
               
               
                 
                   Eq 
                   . 
                   
                       
                   
                    
                   
                     ( 
                     1 
                     ) 
                   
                 
               
             
           
         
       
     
         [0029]    Meanwhile, detection of the vehicle speed is not limited to calculation of the vehicle speed from the wheel speed, but the vehicle speed may be detected by an additional speed sensor. 
         [0030]    The acceleration detector  13  calculates vehicle acceleration from the vehicle speed. The vehicle acceleration is calculated by a change rate of the vehicle speed. That is, the vehicle acceleration is calculated from the below equation. 
         [0000]    
       
         
           
             
               
                 
                   
                     A 
                     i 
                   
                   = 
                   
                     
                       
                         VS 
                         i 
                       
                       - 
                       
                         VS 
                         
                           i 
                           - 
                           1 
                         
                       
                     
                     P 
                   
                 
               
               
                 
                   Eq 
                   . 
                   
                       
                   
                    
                   
                     ( 
                     2 
                     ) 
                   
                 
               
             
           
         
       
     
         [0031]    Herein, A i  indicates the vehicle acceleration at i-th period, VS i  indicates the vehicle speed at i-th period, the WheelSpeed xx,i  indicates the wheel speed at i-th period, and P indicates the period. Generally, the period P means the period where the wheel speed sensor  10  detects the wheel speed. 
         [0032]    Meanwhile, detection of the vehicle acceleration is not limited to calculation of the vehicle acceleration from the vehicle speed, but the vehicle acceleration may be detected by an additional acceleration sensor. 
         [0033]    The vertical acceleration sensor  14  detects a vertical acceleration of the vehicle. In a case of the vehicle provided with an electronic stability program (ESP), the vertical acceleration sensor  14  is mounted basically. However, an additional vertical acceleration sensor  14  may be mounted at the vehicle, if necessary. 
         [0034]    The wheel torque detector  15  calculates torque applied to the wheel. The wheel torque can be calculated from an engine torque and a shift-speed currently engaged, but the calculation of the wheel torque is not limited thereto. The wheel torque may be calculated by mounting an additional sensor to the wheel. 
         [0035]    The ambient temperature sensor  16  detects an ambient temperature of the vehicle. 
         [0036]    The controller  20  is electrically connected to the wheel speed sensor  11 , the vehicle speed detector  12 , the acceleration detector  13 , the vertical acceleration sensor  14 , the wheel torque detector  15  and the ambient temperature sensor  16 . The controller  20  determines whether a wheel slip occurs from the data detected by the data detector  10 , determines a road state if the wheel slip occurs, and performs the starting control by controlling the engine  30  and/or the transmission  40  according to the determined road state. For these purposes, the controller  20  can be realized by one or more processors activated by a predetermined program, and the predetermined program can be programmed to perform each step of a method of controlling starting of a vehicle according to various embodiments of the present invention. 
         [0037]    Hereinafter, referring to  FIG. 2  to  FIG. 4 , a method of controlling starting of a vehicle according to various embodiments of the present invention will be described in detail.  FIG. 2  is a flowchart of a method of controlling starting of a vehicle according to various embodiments of the present invention;  FIG. 3  is a table of the first predetermined wheel slip amount and the second predetermined wheel slip amount set according to a wheel torque; and  FIG. 4  is a table showing a starting control according to various embodiments of the present invention. 
         [0038]    As shown in  FIG. 2 , a method of controlling starting of a vehicle according to various embodiments of the present invention begins with detecting the data for a starting control at step S 110 . That is, the wheel speed sensor  10  detects the wheel speed, the vehicle speed detector  12  detects the vehicle speed, the acceleration detector  13  detects the acceleration, the vertical acceleration sensor  14  detects the vertical acceleration, the wheel torque detector  15  detects the wheel torque, and the ambient temperature sensor  16  detects the ambient temperature. 
         [0039]    If the data detector  10  detects and transmits the data to the controller  20 , the controller  20  calculates a wheel slip amount during the starting at step S 120 . The wheel slip amount is calculated based on the wheel speed, the vehicle speed, and the vehicle acceleration. That is, the wheel slip amount is calculated by subtracting a sum of (i−1)-th vehicle speed and (i−1)-th acceleration from i-th wheel speed. The wheel slip amount of each wheel in the vehicle is calculated. In addition, the wheel slip amount may be calculated only if the vehicle speed is slower than a predetermined vehicle speed. 
         [0040]    If the wheel slip amount is calculated, the controller  20  determines whether the wheel slip occurs at step S 130 . It is determined that the wheel slip occurs if the wheel slip amount is greater than a first predetermined wheel slip amount WS slip,y . That is, it is determined that the wheel slip occurs if any one of the below equations is satisfied. 
         [0000]      WheelSpeed FL,i −( VS   i−1   +A   i−1 )&gt; WS   slip,y 
 
         [0000]      or 
         [0000]      WheelSpeed FR,i −( VS   i−1   +A   i−1 )&gt; WS   slip,y 
 
         [0000]      or 
         [0000]      WheelSpeed RL,i −( VS   i−1   +A   i−1 )&gt; WS   slip,y 
 
         [0000]      or 
         [0000]      WheelSpeed RR,i −( VS   i−1   +A   i−1 )&gt; WS   slip,y   Eq. (3)
 
         [0041]    In addition, the first predetermined wheel slip amount, as shown in  FIG. 3 , may be set according to the wheel torque. 
         [0042]    If it is determined that the wheel slip does not occur at the step S 130 , the controller  20  proceeds to step S 190 . If it is determined that the wheel slip occurs at the step S 130 , the controller  20  determines the road state. It is exemplified in this specification and the drawings that the road state is determined to be an icy road, a rough road or an unpaved road and a slippery road in a named sequence, but the determination sequence is not limited to the named sequence. 
         [0043]    Firstly, the controller  20  determines whether the road state is the icy road at step S 140 . That is, the controller  20  determines that the road state is the icy road if the wheel slip amount is greater than or equal to a second predetermined wheel slip amount WS icy,y  and the ambient temperature is lower than or equal to a predetermined temperature in a state that the wheel slip occurs. That is, it is determined that the road state is the icy road if any one of the below equations is satisfied in a state that the ambient temperature is lower than or equal to the predetermined temperature. 
         [0000]      WheelSpeed FL,i −( VS   i−1   +A   i−1 )&gt; WS   icy,y 
 
         [0000]      or 
         [0000]      WheelSpeed FR,i −( VS   i−1   +A   i−1 )&gt; WS   icy,y 
 
         [0000]      or 
         [0000]      WheelSpeed RL,i −( VS   i−1   +A   i−1 )&gt; WS   icy,y 
 
         [0000]      or 
         [0000]      WheelSpeed RR,i −( VS   i−1   +A   i−1 )&gt; WS   icy,y   Eq. (4)
 
         [0044]    The second predetermined wheel slip amount, as shown in  FIG. 3 , may be set according to the wheel torque. In addition, the predetermined temperature may be 0° C. 
         [0045]    If it is determined that the road state is the icy road at the step S 140 , the controller  20  performs the starting control according to the icy road at step S 160 . As shown in  FIG. 4 , the transmission is controlled using a normal shift pattern, a shift-speed is controlled to be higher than or equal to a second forward speed, and an engine torque is controlled using a first torque filter that is smaller than a normal torque filter in the starting control according to the icy road. Herein, the normal shift pattern means a shift pattern used when the vehicle runs on a normal road. According to the normal shift pattern, a downshift is performed if an accelerator pedal position value increases at a predetermined speed, and an upshift is performed if a speed increases at a predetermined accelerator pedal position value. In addition, the torque filter means a slope with which torque increases or decreases to target torque, and the normal torque filter means the torque filter basically set in the vehicle. 
         [0046]    It is determined that the road state is not the icy road at the step S 140 , the controller  20  determines whether the road state is the rough road or the unpaved road at step S 150 . That is, the controller  20  determines that the road state is the rough road or the unpaved road if the road state is not the icy road, and the number of times an absolute value of third derivative of the vertical acceleration of the vehicle is greater than a predetermined value is greater than or equal to a predetermined number during a predetermined time in a state that the wheel slip occurs. 
         [0047]    It is determined that the road state is the rough road or the unpaved road at the step S 150 , the controller  20  performs the starting control according to the rough road or the unpaved road at step S 170 . As shown in  FIG. 4 , the transmission is controlled using a hold shift pattern, the shift-speed is controlled to be higher than or equal to the second forward speed, and the engine torque is controlled using the first torque filter that is smaller than the normal torque filter in the starting control according to the rough road or the unpaved road. According to the hold shift pattern, the downshift is not performed even though the accelerator pedal position value increases to a specific accelerator pedal position value at a predetermined speed. That is, the shift does not occur until the accelerator pedal position value changes greatly according to the hold shift pattern. 
         [0048]    If it is determined that the road state is not the rough road or the unpaved road at the step S 150 , the controller  20  determines that the road state is the slippery road and performs the starting control according to the slippery road at step S 180 . That is, the controller  20  determines that the road state is the slippery road if the road state is not the icy road and the rough road or the unpaved road in a state that the wheel slip occurs. 
         [0049]    As shown in  FIG. 4 , the transmission is controlled using the hold shift pattern, the shift-speed is controlled to be a first forward speed, and the engine torque is controlled using a second torque filter that is greater than the normal torque filter and is smaller than the first torque filter in the starting control according to the slippery road. 
         [0050]    During performing the starting control according to the road state, the controller  20  determines whether a release condition of the starting control according to the road state is satisfied at the step S 190 . The release condition of the starting control according to the road state may be satisfied when the vehicle speed is faster than or equal to a predetermined vehicle speed, or the number of times wheel slip does not occur continuously is greater than or equal to a predetermined number during performing the starting control according to the road state due to occurrence of the wheel slip. 
         [0051]    If the release condition of the starting control according to the road state is not satisfied at the step S 190 , the controller  20  proceeds to the step S 110 . On the contrary, if the release condition of the starting control according to the road state is satisfied at the step S 190 , the controller  20  releases the starting control according to the road state at step S 200  and finishes the method of controlling the starting according to various embodiments. Therefore, the controller  20  controls the engine  30  and the transmission  40  normally. That is, the controller  20  controls the transmission  40  by using the normal shift pattern and controls the engine  30  by using the normal torque filter and a normal torque map. 
         [0052]    As described above, safety may be improved by performing the starting control according to the road state. In addition, since a customer does not need to learn suitable manipulation to each road state, customer convenience may be improved. 
         [0053]    The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents.