Apparatus and method for controlling creep torque in an environmentally friendly vehicle

Abstract

A device for controlling creep torque in an environmentally friendly vehicle, the device comprising: a user interface (110) configured to generate a creep cruise control function set signal or a creep cruise control function shutdown signal; Detectors (120-160) configured to detect travel-related information of the vehicle, the detectors comprising a distance detector (120) configured to measure a distance from another vehicle located in front of the vehicle in the direction of travel; and a controller (170, 171) configured to calculate a rolling resistance based on the travel-related information when the creep cruise control function setting signal is received, wherein the controller is further configured to determine whether the distance from the other vehicle is shorter than a reference inter-vehicle distance in the event that the vehicle satisfies a creep cruise control operating condition; and wherein the controller is further configured to variably control the creep torque taking into account the calculated rolling resistance when the distance from the other vehicle is shorter than the reference inter-vehicle distance.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a creep torque control apparatus and method in an environmentally friendly vehicle. More particularly, the present disclosure relates to a creep torque control apparatus and method for variably controlling creep torque in an environmentally friendly vehicle with respect to rolling resistance of the vehicle. BACKGROUND OF THE INVENTION

[0002] In recent years, environmental discussions have increased consumer interest in environmentally friendly vehicles, and studies for electric vehicles (HEVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and the like have been increasingly carried out.

[0003] These eco-friendly vehicles do not generate creep torque, in which even though a driver depresses an accelerator pedal in an automatic transmission vehicle having an internal combustion engine, when the driver releases a brake pedal, idle torque of the engine is supplied to a torque converter so that the vehicle accelerates slowly.

[0004] From DE 10 2009 053 294 A1, a device for controlling a creep torque in an environmentally friendly vehicle is known, the device comprising: a user interface configured to generate a creep cruise control function setting signal or a creep cruise control function shutdown signal; detectors configured to detect trip-related information of the vehicle; and a controller configured to calculate a rolling resistance based on the trip-related information when the creep cruise control function setting signal is received, and to variably control the creep torque taking into account the calculated rolling resistance depending on whether the vehicle satisfies a creep cruise control operating condition.

[0005] DE 10 2004 013 512 A1 discloses a method and a device for influencing an actual engine torque output by an engine that is part of the drive means of a vehicle. It relates to an assistance function for performing a crawling motion of a vehicle, even during an uphill start or uphill drive. For this purpose, the actual engine torque during an uphill start or uphill drive is determined as a function of a road gradient variable, which describes a road gradient in the direction of travel, and a brake pedal variable, which describes a deflection of a brake pedal interacting with the vehicle's braking means, caused by the vehicle driver.

[0006] DE 10 2015 111 212 A1 provides a vehicle travel control device comprising: an electric motor that generates creep torque; a preceding vehicle following control section that performs preceding vehicle following control for adjusting an inter-vehicle distance between a preceding vehicle and a host vehicle based on a traveling state of the preceding vehicle, the preceding vehicle following control being continued until the host vehicle enters a stopped state; and a creep torque control section that controls creep torque control, the creep torque control section maintaining a target value of creep torque to be generated by the electric motor at a predetermined value during a period in which the preceding vehicle following control is performed and the host vehicle is traveling.

[0007] DE 10 2014 002 851 A1 describes a vehicle control device. A control unit is configured to control a torque magnitude of creep torque to be generated by a drive motor for driving a vehicle. A vehicle speed detection unit is configured to detect a vehicle speed. A brake operation detection unit is configured to detect an operation of a brake. A road surface condition acquisition unit is configured to calculate or detect an inclination angle of a road surface on which the vehicle stops.The control unit includes a torque magnitude changing unit configured to change the torque magnitude according to the inclination magnitude of the road surface acquired by the road surface condition acquiring unit, if a stop state of the vehicle is detected by the vehicle speed detected by the vehicle speed detecting unit and the operation of the brake is detected by the brake operation detecting unit.

[0008] In addition, DE 102 21 835 A1 shows a method for controlling a starting element (e.g. a hydrodynamic converter, a clutch or, in the case of hybrid drives, an electric motor) of a motor vehicle in creep mode, wherein a creep torque setpoint is set on the starting element, which is set as a function of at least one of the following environmental conditions or driver specifications of the motor vehicle: A) the current inclination of the motor vehicle, B) the brake pedal pressure applied by a driver of the motor vehicle, C) the distance of the motor vehicle to obstacles and D) the driver type.

[0009] The disclosure of this section is intended to provide a background to the invention. Applicant acknowledges that this section may contain information available prior to this application. However, by providing this section, applicant does not admit that any information contained in this section constitutes prior art. SUMMARY

[0010] As described above, drivers experience fatigue as a result of frequent accelerator and brake pedal activations in low-speed situations, such as extremely congested sections during rush hour or when passing fast-food restaurants. Advanced Smart Cruise Control (ASCC) technology can be used to address this problem. However, the implementation of ASCC technology requires the addition of a high-cost radar device.

[0011] The present disclosure has been made to solve the above-mentioned problems and other problems.

[0012] One aspect of the present disclosure provides a creep torque control apparatus and method for variably controlling a creep torque in an environmentally friendly vehicle with respect to a rolling resistance of the vehicle.

[0013] Another aspect of the present disclosure provides a creep torque control apparatus and method for measuring a vehicle-to-vehicle distance (inter-vehicle distance) by using an ultrasonic sensor used in an existing smart parking assist system (SPAS) without additional hardware and for variably controlling a creep torque in an environmentally friendly vehicle with respect to the measured inter-vehicle distance.

[0014] The technical problems that the present disclosure aims to solve are not limited to the problems mentioned above, and other technical problems not mentioned here can be easily understood from the following description by those of ordinary skill in the art to which the present disclosure refers.

[0015] According to one aspect of the present disclosure, an apparatus for controlling creep torque in an environmentally friendly vehicle comprises a user interface that generates a creep cruise control function disable signal or a creep cruise control function disable signal, detectors that detect travel-related information of the vehicle, the detectors comprising a distance detector (120) configured to measure a distance from another vehicle located ahead of the vehicle in the travel direction, and a controller that calculates a rolling resistance based on the travel-related information when the creep cruise control function setting signal is received, the controller further configured to determine whether the distance from the other vehicle is shorter than a reference inter-vehicle distance in the event that the vehicle satisfies a creep cruise control operating condition;and wherein the controller is further configured to variably control the creep torque taking into account the calculated rolling resistance when the distance from the other vehicle is shorter than the reference inter-vehicle distance.;

[0016] The detectors include a pedal operation detector that detects whether an accelerator pedal and a brake pedal are operated, a tilt angle detector that detects a tilt angle of a road on which the vehicle is traveling, a speed detector that detects a vehicle speed of the vehicle, and a steering angle detector configured to detect a steering angle of the vehicle.

[0017] The distance detector can detect the distance from the other vehicle using one or more ultrasonic sensors.

[0018] The pedal operation detector can detect whether the accelerator pedal and the brake pedal are operated via an accelerator pedal sensor and a brake pedal sensor.

[0019] The inclination angle detector can detect the inclination angle of the road via an acceleration sensor.

[0020] The controller can calculate the rolling resistance based on the inclination angle and vehicle speed.

[0021] The controller may determine whether the creep cruise control operating condition is met based on the distance from the other vehicle, the vehicle speed, the steering angle, whether the accelerator pedal and the brake pedal are applied, and the rolling resistance.

[0022] The controller may determine whether the creep cruise control operating condition is met by determining whether the vehicle can be stopped within the distance from the other vehicle by rolling resistance alone.

[0023] The controller can determine whether there is no application of the brake pedal and the accelerator pedal and can determine whether the steering angle is less than or equal to a reference steering angle.

[0024] The controller may control the creep torque by referring to a mapping table indicating values ​​of creep torque versus speed when the distance from the other vehicle is greater than or equal to the reference inter-vehicle distance.

[0025] According to another aspect of the present disclosure, a method for controlling creep torque in an eco-friendly vehicle includes detecting travel-related information via detectors mounted in the vehicle when a creep cruise control function is set, the travel-related information including a distance from another vehicle located ahead of the vehicle in the travel direction; calculating a rolling resistance based on the travel-related information; determining whether the vehicle satisfies a creep cruise control operating condition based on the travel-related information and the rolling resistance; determining whether the distance from the other vehicle is shorter than a reference inter-vehicle distance when the vehicle satisfies the creep cruise control operating condition;and variably controlling the creep torque with respect to the rolling resistance when the distance from the other vehicle is shorter than the reference inter-vehicle distance;

[0026] The detection of the trip-related information may include detecting whether an accelerator pedal and a brake pedal are operated, a road inclination angle, a vehicle speed and a steering angle.

[0027] Determining whether the vehicle satisfies the creep control operating condition may include determining whether the vehicle can be stopped within the distance from the other vehicle by rolling resistance alone.

[0028] The method may further comprise controlling the creep torque with reference to a mapping table indicating values ​​of creep torque as a function of speed when the distance from the other vehicle is longer than or equal to the reference inter-vehicle distance.

[0029] The method may further include disabling the creep cruise control function if the vehicle does not meet the creep cruise control operating condition.

[0030] According to embodiments of the present disclosure, by variably controlling the creep torque in consideration of the rolling resistance of the vehicle, it is possible to remove frequent operations of the accelerator pedal and the brake pedal in low-speed situations, thereby improving user convenience and improving fuel efficiency.

[0031] In addition, according to embodiments of the present disclosure, by measuring the inter-vehicle distance using the ultrasonic sensor used in an existing intelligent parking assist system (SPAS) without additional hardware and by variably controlling the creep torque in consideration of the measured inter-vehicle distance, it is not necessary to add high-priced equipment (hardware), thereby preventing cost increase. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. In the drawings: Fig. 1 is a graphical representation showing a coasting torque according to speed; Fig. 2 is a block diagram of a creep torque control device of an environmentally friendly vehicle according to an embodiment of the present disclosure; Fig. 3A to Fig. 3C views for explaining a relationship between a rolling resistance, a creep torque and a drive torque; Fig. 4 is a view for explaining inter-vehicle distance control by creep torque variation in accordance with embodiments of the present disclosure; Fig. 5 is a flowchart illustrating a method for controlling creep torque in an environmentally friendly vehicle in accordance with an embodiment of the present disclosure; and Fig. 6 and Fig. 7 views for explaining creep torque control in accordance with embodiments of the present disclosure. DETAILED DESCRIPTION

[0033] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used throughout to denote the same or equivalent elements. In addition, a detailed description of well-known features or functions is omitted in order not to unnecessarily obscure the scope of the present disclosure.

[0034] Terms such as "first," "second," "A," "B," "(a)," "(b)," and the like may be used herein to describe elements of the present disclosure. Such terms are used only to distinguish one element from another, and the subject matter, sequence, order, or number of these elements is not limited by these terms. Furthermore, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art in the technical field to which the present disclosure relates.Terms, such as those defined in commonly used dictionaries, are intended to be interpreted to have a meaning consistent with their meaning in the context of the related subject matter, and are not interpreted in an idealized or overly formal sense, except as so defined herein.

[0035] The present disclosure relates to a creep cruise control (CCC). Creep cruise control is a technology for simulating creep travel by controlling creep torque in a procedure in which an engine is stopped (idle stop & go) and a motor is driven.

[0036] One aspect of the present invention provides a system and method for creep drive control of a hybrid or electric vehicle. When the driver releases the vehicle's brake pedal, a controller of the vehicle controls a wheel drive motor so that the vehicle moves forward (creep drive) even without an accelerator pedal operation. In embodiments, for creep drive, an internal combustion engine does not operate to propel the vehicle forward. In embodiments, creep drive is automatically activated in response to a brake pedal release or is manually activated by a separate driver operation of a switch or lever.

[0037] After activating a creep drive mode, the controller determines an initial distance ( Fig. 7, d detect ) between the vehicle in question and the vehicle in front. The controller determines whether the first distance (ddetect ) greater than a reference distance (d ref ) before determining a target creep torque for controlling the wheel drive motor.

[0038] If in embodiments it is determined that the first distance (d detect ) greater than the reference distance (d ref ), then the controller determines a target creep torque (coasting torque) using a predetermined speed-torque profile (table, map) and controls the wheel drive motor to produce the target creep torque. In embodiments, the controller does not consider a current rolling resistance of the vehicle to determine the creep torque when using the predetermined speed-torque profile. In embodiments, when the controller uses a Fig. Using the profile shown in Figure 3, the vehicle would reach a final speed (10 km / h) of creeping when the creep torque and rolling resistance are balanced.

[0039] If in embodiments it is determined that the first distance (d detect ) smaller than the reference distance (d ref ), then the controller calculates a target creep torque and controls the wheel drive motor to maintain the target creep torque until the vehicle reaches a target distance (d target ) from the preceding vehicle, so that the vehicle stops at the target distance from the preceding vehicle, as shown in the distance profile of the Fig. 7. In embodiments, the controller calculates the target creep torque using Equation 6 shown in Fig. 7 is shown.

[0040] Fig. Figure 1 is a graph showing coasting torque versus speed.

[0041] A coasting torque can be generated when a driver does not apply a brake pedal or an accelerator pedal. How Fig. As shown in Figure 1, coasting torque can be divided into creep torque and engine braking torque. Creep torque can be generated because engine idle torque is delivered to a torque converter in a low-speed situation. Engine braking torque can be generated because, in a high-speed situation, engine speed must be higher than idle speed.

[0042] Since an environmentally friendly vehicle is driven by an engine at low speed and an engine clutch is disengaged even during a high-speed coasting operation, the coasting must be simulated by the engine. In this case, creep torque has only positive (+) values, as shown in the graphical representation of the Fig. 1. Consequently, the creep torque can be reduced by the rolling resistance of the vehicle.

[0043] Fig. 2 is a block diagram of a creep torque control device of an environmentally friendly vehicle in accordance with an embodiment of the present disclosure. Fig. 3A to Fig. 3C are views for explaining a relationship between a rolling resistance, a creep torque, and a driving torque. Fig. 4 is a view for explaining inter-vehicle distance control via creep torque variation according to embodiments of the present disclosure.

[0044] As in Fig. 2, a creep torque control device 100 may include a user interface 110, a distance detector 120, a pedal operation detector 130, a tilt angle detector 111, a speed detector 150, a steering angle detector 160, a controller 170, and a motor 180.

[0045] The user interface 110 may generate data in response to a user actuation. The user interface 110 may be implemented with a dome switch, a toggle switch, a touch button, or the like.

[0046] A user may actuate user interface 110 to set or disable a creep cruise control (CCC) function. User interface 110 may generate a CCC function set signal or a CCC function disable signal according to the user actuation.

[0047] The distance detector 120 can measure the distance from another vehicle in front of and / or behind the vehicle. The distance detector 120 can be implemented with one or more ultrasonic sensors. For example, four to six ultrasonic sensors can be mounted on a front bumper and a rear bumper of the vehicle.

[0048] In the present disclosure, the distance detector 120 may measure the distance from another vehicle located in front of the vehicle in a traveling direction. If the vehicle is moving forward, the distance detector 120 may measure the distance from, for example, a vehicle in front. If the vehicle is moving backward, the distance detector 120 may measure the distance from a vehicle behind the vehicle. In this case, the vehicle's traveling direction may be identified via a gear position sensor.

[0049] The pedal operation detector 130 can detect whether an accelerator pedal and / or a brake pedal are depressed. The pedal operation detector 130 can detect whether a driver is depressing the pedals via an accelerator pedal sensor (ABS) and a brake pedal sensor (BBS).

[0050] The inclination angle detector 140 can measure the inclination angle θ of a road on which the vehicle is located (on which the vehicle is traveling). The inclination angle detector 140 can measure the road inclination angle using an acceleration sensor.

[0051] The speed detector 150 can detect the speed of the vehicle (vehicle speed). The speed detector 51 can calculate the vehicle speed using vehicle position and time information obtained via a global positioning system (GPS). Alternatively, the speed detector 150 can measure the vehicle speed via a speed sensor mounted in the vehicle.

[0052] The steering angle detector 160 may measure (detect) a steering angle (a rotation angle of a steering wheel) via a steering angle sensor configured to detect a rotation of the steering wheel.

[0053] The controller 170 may detect information related to a travel of the vehicle (travel-related information) via the detectors 120-160 when a CCC function setting signal is input from the user interface 110. The controller 170 may calculate a rolling resistance based on the travel-related information and may determine whether to perform CCC. If the controller 170 determines that CCC is to be performed, the controller 170 may determine whether the distance from another vehicle located ahead of the vehicle in a travel direction is shorter than a reference inter-vehicle distance (reference inter-vehicle distance). If the distance between the vehicles is shorter than the reference inter-vehicle distance, the controller 170 may variably control a creep torque taking into account the calculated rolling resistance.When the distance between vehicles is greater than or equal to the reference inter-vehicle distance, the controller 170 may also control creep torque using an existing control method. The creep torque may refer to motor torque during creep travel.

[0054] The controller 170 can be implemented with an electronic control unit (ECU), a hybrid control unit (HCU), or a motor control unit (MCU). The controller 170 can have internal or external memory. The memory can store ride-related information, rolling resistance, a mapping table, various types of setting information, and the like.

[0055] The controller 170 may include a rolling resistance calculation unit 171, an operation determination unit 172, and a motor torque calculation unit 173.

[0056] The rolling resistance calculation unit 171 can calculate rolling resistance using a road inclination angle and a vehicle speed. A rolling resistance measured previously may vary depending on the condition or deterioration of the road. Accordingly, the rolling resistance can be corrected for inter-vehicle distance control.

[0057] Generally, a stationary object starts moving under Coulomb friction when the object exceeds the maximum static friction force and then the kinetic friction force has a lower value than the maximum static friction force. Accordingly, if the behavior of the vehicle is observed immediately after a vehicle movement, the rolling resistance can be corrected using an equation of motion for the vehicle. The rolling resistance calculation unit 171 can calculate a rolling resistance F R.R. by using equation 1 given below: FR.R.=Ma−Fcreep−Mgsinθ

[0058] In equation 1, M denotes the mass of the vehicle, A denotes the acceleration of the vehicle, F creep denotes a creep force generated by a creep torque, g denotes the acceleration due to gravity, and θ denotes a road inclination angle.

[0059] The rolling resistance calculation unit 171 can update the rolling resistance stored in the memory to the calculated rolling resistance.

[0060] The operation determination unit 172 may determine whether to execute a CCC function when a CCC function setting signal is received. In this case, to determine whether to execute the CCC function, the operation determination unit 172 may determine whether the vehicle can be completely stopped within the inter-vehicle distance detected by the distance detector 120 using only the rolling resistance output from the rolling resistance calculation unit 171. Here, the detected inter-vehicle distance may refer to the distance from another vehicle located ahead of the vehicle in a traveling direction.

[0061] In general, the acceleration of the vehicle can be obtained by equation 2 given below. Ma=Ftraction−Faero+FR.R.+Mgsinθ

[0062] In equation 2, F tractiona driving force, Mgsinθ denotes a gradient resistance and F aero refers to an air resistance (equivalent longitudinal drag force).

[0063] In the case of a CCC implementation, equation 2 can be simplified into equation 3 since the CCC is restricted to a low-speed situation, so air resistance can be negligible and there is no driving force caused by accelerator pedal operation. Ma=Fcreep+FR.R.+Mgsinθ

[0064] The vehicle must be able to maintain a creep speed between a detectable distance d spec an ultrasonic sensor and a target inter-vehicle distance (target distance) d targetand then be completely stopped by rolling resistance alone. Therefore, an operating condition must satisfy Equation 5 in accordance with an acceleration-distance-speed relationship (Equation 4). 2as=ν2−ν02 FR.R.+MgsinθM=a<−+νcreeping22(dspec−dtarget)

[0065] In equation 5, s denotes a travel distance, v 0 denotes the initial velocity, v (= 0) denotes the final velocity and v creeping refers to a creep speed. The war speed, which is a vehicle speed when a creep torque is equivalent to a rolling resistance, can be approximately 10 km / h (kilometers per hour).

[0066] Furthermore, in the case of a large steering angle, a vehicle positioned in front of the vehicle in one direction of travel cannot be detected, and therefore the steering angle must be limited in terms of the measuring range of an ultrasonic sensor. For example, if the ultrasonic sensor can perform a measurement in the range of 30°, then the steering angle can be limited to 15° or less in the left-right direction.

[0067] Operating conditions are summarized as follows with regard to the above considerations. 1) a case where the inclination angle of a road on which the vehicle is traveling (the road inclination angle) is less than or equal to a reference inclination angle. 2) a case where a steering angle is less than or equal to a reference steering angle. 3) a case where the brake pedal and an accelerator pedal are not operated. 4) a case where a calculated rolling resistance is higher than or equal to a reference rolling resistance. 5) a case where a vehicle speed is lower than or equal to a reference vehicle speed.

[0068] Here, the reference tilt angle, the reference rolling resistance, and the reference vehicle speed can be determined to satisfy the above equation 5. Furthermore, the reference steering angle can be determined by the specification of the steering angle sensor.

[0069] The operation determination unit 172 may determine whether the vehicle meets the aforementioned operating conditions. If the vehicle meets all five operating conditions, the operation determination unit 172 may determine to perform a CCC.

[0070] If the rolling resistance calculated by the rolling resistance unit 171 and the road inclination angle and vehicle speed detected by the detectors 140 and 150 satisfy Equation 5, the operation determination unit 172 may determine that the vehicle can be completely stopped within the detected inter-vehicle distance by only the calculated rolling resistance. That is, if the road inclination angle is less than or equal to the reference inclination angle, the calculated rolling resistance is higher than or equal to the reference rolling resistance, and the vehicle speed is less than or equal to the reference vehicle speed, the operation determination unit 172 may determine that the vehicle can be completely stopped within the detected inter-vehicle distance by only the calculated rolling resistance.

[0071] If the vehicle fails to meet one or more of the five operating conditions, the operation determination unit 172 may also disable the CCC function. In doing so, the operation determination unit 172 may output a message to notify the disabling of the CCC function using visual and / or audible information.

[0072] The engine torque calculation unit 173 can determine whether an inter-vehicle distance d detect , which is detected by the distance detector 120, is greater than a reference inter-vehicle distance d ref If the detected inter-vehicle distance d detect is shorter than the reference vehicle spacing d ref , then the motor torque calculation unit 173 can control the inter-vehicle distance by variably controlling a creep torque in consideration of the calculated rolling resistance. At this time, if the detected inter-vehicle distance d detectlonger than or equal to the reference inter-vehicle distance d ref , then the motor torque calculation unit 173 can execute an existing creep control.

[0073] If the detected inter-vehicle distance d detect longer than or equal to the reference inter-vehicle distance d ref , the engine torque calculation unit 173 may calculate an engine torque for generating a creep torque according to the detected vehicle speed, with reference to the mapping table previously stored in the memory. Here, the mapping table may be a table obtained by measuring naturally generated torque in an automatic transmission vehicle with an internal combustion engine according to a vehicle speed and mapping the measured creep torque to the vehicle speed.

[0074] If the detected vehicle distance d detectis shorter than the reference vehicle spacing d ref , then the motor torque calculation unit 173 can calculate a creep force F creep by equation 6. In this case, the vehicle can move at a given acceleration to arrive at a point separated by a target distance d target from the vehicle in front of the vehicle in the direction of travel. Fcreep=−Mν022(ddetect−dtarget)−FR.R.−Mgsinθ

[0075] The motor torque calculation unit 173 may calculate a drive torque for driving the motor 180 taking into account a tire radius, a gear ratio, among the like, in addition to the calculated creep force F Creep , calculate. In this case, the creep torque cannot have a negative (-) value, but the drive torque can have a negative (-) value taking into account the rolling resistance of the vehicle.

[0076] As in Fig. As shown in Figure 3A, the final torque output by vehicle wheels can be calculated as the sum of creep torque and rolling resistance. Fig. As shown in Figure 3B, when the creep torque is equal to the absolute value of the rolling resistance, the drive torque may be 0 Nm, and the vehicle speed at this time may be referred to as a creep speed. Accordingly, the vehicle may travel at a constant creep speed of approximately ten km / h. In the case of active control of the drive torque independent of the vehicle speed, the drive torque may have a drive torque range that is Fig. 3C. Accordingly, although the creep torque is positive (+), the drive torque obtained by adding the creep torque to the rolling resistance may be negative (-), and the vehicle may thus slow down (decelerate).

[0077] As in Fig. 4, the controller 170 can calculate a creep force by applying the difference e between the inter-vehicle distance d detect , which is measured by the distance detector 120, and the target distance d target to Equation 6. In the case of controlling the creep force as described above, the vehicle V can travel at a given acceleration to stop at a point separated from the target distance d target away from the vehicle in front of the vehicle in the direction of travel. That is, the controller 170 can control the vehicle speed at a predetermined acceleration to control the distance from the vehicle in front.

[0078] The motor 180 can generate power under the control of the controller 170 to propel the vehicle. The motor 180 can drive using the motor torque calculated by the motor torque calculation unit 173 of the controller 170.

[0079] Fig. 5 is a flowchart illustrating a method for controlling creep torque in an environmentally friendly vehicle according to an embodiment of the present invention.

[0080] The controller 170 may establish a creep cruise control (CCC) function in response to user input data transferred from the user interface 110 (step S110). For example, if a user presses a button on the user interface 110 assigned a function for setting and disabling the CCC function, the controller 170 may set (enable) or disable (deactivate) the CCC function in response to the user's actuation of the button.

[0081] If the CCC function is set, the controller 170 can measure the distance from another vehicle located in front of the vehicle in a traveling direction via the distance detector 120 (step S120). If a CCC function setting signal is input from the user interface 110, the controller 170 can detect vehicle-related information through the detectors 120-160.

[0082] The controller 170 may calculate a rolling resistance of the vehicle by using the road inclination angle measured by the inclination angle detector 140 and the vehicle speed detected by the speed detector 150 (step S130). The controller 170 may calculate the rolling resistance using Equation 1.

[0083] The controller 170 may determine whether the vehicle meets the operating conditions for the CCC function (step S140). In other words, the controller 170 may determine whether the vehicle is capable of being completely stopped within the measured inter-vehicle distance using only the calculated rolling resistance based on the inter-vehicle distance, the road inclination angle, and the vehicle speed detected by the distance detector 120, the inclination angle detector 140, and the speed detector 150. Furthermore, the controller 170 may determine whether a driver is depressing the brake pedal and the accelerator pedal via the pedal depressing detector 130, and may determine whether the steering angle measured by the steering angle detector 160 is less than or equal to a reference steering angle.

[0084] In the case where the vehicle meets the operating conditions, the controller 170 may determine whether the inter-vehicle distance d detected (measured) by the distance detector 120 detect is shorter than the reference vehicle spacing d ref (Step S150).

[0085] If the measured vehicle distance d detect is shorter than the reference vehicle spacing d ref , then the controller 170 may calculate a creep torque taking into account the rolling resistance (step S160). In other words, the controller 170 may calculate a creep force taking into account the difference between the detected inter-vehicle distance d detect and the target distance d target Further, the controller 170 may calculate an engine torque in terms of a tire radius, a gear ratio, and the like, in addition to the calculated creep force.

[0086] If the calculated vehicle spacing d detect longer than or equal to the reference inter-vehicle distance d ref , the controller 170 may calculate a creep torque by referring to a map table (step S170). In other words, the controller 170 may calculate an engine torque for generating a creep torque in accordance with the vehicle speed detected by the speed detector 150 by referring to the map table (step S170).

[0087] The controller 170 may control the motor 180 to generate the calculated creep torque (step S180). That is, the controller 170 may drive the motor 180 using the calculated motor torque.

[0088] If the vehicle does not meet the operating conditions, the controller 170 may also disable the CCC function (step S190). In this case, the controller 170 may display a message on a display or output the message through a speaker to notify that the CCC function is disabled. Alternatively, the controller 170 may output the corresponding notification via the display and speaker.

[0089] Fig. 6 and Fig. 7 are views for explaining creep torque control according to embodiments of the present disclosure.

[0090] As in Fig. As shown in Figure 6, when there is no vehicle in front of a vehicle moving forward, the controller 170 may control a creep torque based on a mapping table (a speed-coast torque map). That is, the controller 170 may control the creep torque depending on the detected vehicle speed.

[0091] If the distance d detect between the vehicle and a vehicle in front is shorter than the reference inter-vehicle distance d ref then the vehicle speed at the point where the vehicle distance d detec equal to the target distance d target is 0 km / h. Consequently, and as in Fig. As shown in Fig. 7, creep torque control can be executed to linearly reduce the speed to make the vehicle speed equal to 0 km / h when the inter-vehicle distance d detect the target distance d targetIn this case, proportional-integral-derivative (PID) control can be applied to the torque control.

[0092] Logical blocks, modules, or units described in connection with embodiments disclosed herein may be implemented or executed by a computing device having at least one processor, at least one memory, and at least one communication interface. The elements of a method, process, or algorithm described in connection with embodiments disclosed herein may be implemented directly in hardware, in a software module executed by at least one processor, or in a combination of the two. Computer-executable instructions for implementing a method, process, or algorithm described in connection with embodiments disclosed herein may be stored in a non-transitory computer-readable storage medium.

[0093] Although the present disclosure has been described with reference to embodiments and the accompanying drawings, the present disclosure is not limited thereto, but can be variously modified and changed by a person skilled in the art in the technical field to which the present disclosure relates without departing from the spirit and scope of the present disclosure.

[0094] Therefore, embodiments of the present disclosure are provided to illustrate the spirit and scope of the present disclosure, but not to limit it, so that the spirit and scope of the present disclosure are not limited by the embodiments. The scope of the present disclosure should be delimited based on the claims, and all technical ideas within the scope that are equivalent to the original claims are included in the scope of the present disclosure.

Claims

[1] A device for controlling creep torque in an environmentally friendly vehicle, the device comprising: a user interface (110) configured to generate a creep cruise control function set signal or a creep cruise control function shutdown signal; Detectors (120-160) configured to detect travel-related information of the vehicle, the detectors comprising a distance detector (120) configured to measure a distance from another vehicle located in front of the vehicle in the direction of travel; and a controller (170, 171) configured to calculate a rolling resistance based on the travel-related information when the creep cruise control function setting signal is received, wherein the controller is further configured to determine whether the distance from the other vehicle is shorter than a reference inter-vehicle distance in the event that the vehicle satisfies a creep cruise control operating condition; and wherein the controller is further configured to variably control the creep torque taking into account the calculated rolling resistance when the distance from the other vehicle is shorter than the reference inter-vehicle distance. [2] The apparatus of claim 1, wherein the detectors further comprise: a pedal operation detector (130) configured to detect whether an accelerator pedal and a brake pedal are operated; an inclination angle detector (140) configured to detect an inclination angle of a road on which the vehicle is traveling; a speed detector (150) configured to detect a vehicle speed of the vehicle; and a steering angle detector (160) configured to detect a steering angle of the vehicle. [3] The apparatus of claim 1, wherein the distance detector (120) is configured to detect the distance from the other vehicle via one or more ultrasonic sensors. [4] The apparatus according to claim 2, wherein the pedal operation detector (130) is configured to detect whether the accelerator pedal and the brake pedal are operated by an accelerator pedal sensor and a brake pedal sensor. [5] The apparatus of claim 2, wherein the inclination angle detector (140) is configured to detect the inclination angle of the road via an acceleration sensor. [6] The apparatus of claim 2, wherein the controller (170) is configured to calculate the rolling resistance based on the inclination angle and the vehicle speed. [7] The apparatus of claim 6, wherein the controller (170) is configured to determine whether the creep cruise control operating condition is satisfied based on the distance from the other vehicle, the vehicle speed, the steering angle, whether the accelerator pedal and the brake pedal are depressed, and the rolling resistance. [8] The apparatus of claim 7, wherein the controller (170) is configured to determine whether the creep cruise control operating condition is satisfied by determining whether the vehicle can be stopped within the distance from the other vehicle by rolling resistance alone. [9] The apparatus of claim 8, wherein the controller (170) is configured to determine whether there is no application of the brake pedal and the accelerator pedal and to determine whether the steering angle is less than or equal to a reference steering angle. [10] The apparatus of claim 1, wherein the controller (170) is configured to control the creep torque with reference to a mapping table (S170, S180) indicating values ​​of creep torque versus speed when the distance from the other vehicle is longer than or equal to the reference inter-vehicle distance. [11] A method for controlling creep torque in an environmentally friendly vehicle, the method comprising: Detecting (S120) travel-related information via detectors (110-160) mounted in the vehicle when a creep cruise control function is set, the travel-related information including a distance from another vehicle located ahead of the vehicle in the travel direction; Calculating (S130) a rolling resistance based on the trip-related information; Determining (S140) whether the vehicle satisfies a creep cruise control operating condition based on the travel-related information and the rolling resistance; Determining (S150) whether the distance from the other vehicle is shorter than a reference inter-vehicle distance when the vehicle satisfies the creep cruise control operating condition; and variable control of creep torque taking rolling resistance into account when the distance from the other vehicle is shorter than the reference inter-vehicle distance. [12] The method of claim 11, wherein detecting the trip-related information comprises: Detecting whether an accelerator pedal and a brake pedal are pressed, a road inclination angle, a vehicle speed and a left angle. [13] The method of claim 12, wherein determining whether the vehicle satisfies the creep cruise control operating condition comprises: Determine whether the vehicle can be stopped within the distance from the other vehicle by rolling resistance alone. [14] The method of claim 11, further comprising: Controlling (S170, S180) the creep torque with reference to a map table indicating values ​​of creep torque depending on the speed when the distance from the other vehicle is longer than or equal to the reference inter-vehicle distance. [15] The method of claim 12, further comprising: Disabling (S190) the creep control function when the vehicle does not meet the creep control operating condition.

Images