Patent Publication Number: US-9850839-B2

Title: System and method for hill ascent speed assistance

Description:
TECHNICAL FIELD 
     The present disclosure generally relates to a powertrain control of a vehicle and, more specifically, systems and methods for hill ascent speed assistance. 
     BACKGROUND 
     Vehicle cruise control systems have evolved over time to include adaptive features such as using distance and speed of another vehicle in front of the particular vehicle to be more efficient when managing variable traffic flow. However, the vehicle cruise control systems do not perform well when the road geometry changes. As the vehicle ascends a hill, the vehicle slows noticeably as it fights the forces of gravity to maintain speed. The vehicle cruise control system increases the throttle to compensate and maintain a set speed. Because the vehicle cruise control system is reacting to the road geometry changes, the transmission must shift and greatly increase the engine revolutions per minute (RPM) to return the vehicle to the set speed. This phenomenon is particularly noticeable when the vehicle is towing a trailer. Often, the vehicle will slow by five miles per hour (MPH) or more before the vehicle cruise control system reacts. As a result, of greatly increasing the throttle, strain is exerted on the powertrain of the vehicle. 
     SUMMARY 
     The appended claims define this application. The present disclosure summarizes aspects of the embodiments and should not be used to limit the claims. Other implementations are contemplated in accordance with the techniques described herein, as will be apparent to one having ordinary skill in the art upon examination of the following drawings and detailed description, and these implementations are intended to be within the scope of this application. 
     Exemplary embodiments provide systems and methods to assist a vehicle ascending a hill. According to one embodiment, a vehicle includes a trailer connection component configured to determine whether a trailer is connected to the vehicle. The example vehicle also includes a road geometry component configured to determine a slope of a road on which the vehicle is driving. The example vehicle also includes a vehicle payload component configured to determine a gross vehicle weight of the vehicle. The example vehicle also includes a throttle adjuster configured to adjust a throttle based on the gross vehicle weight to maintain a set speed. 
     According to another embodiment, an example method includes determining a connection status of a trailer. The example method also includes determining a slope of a road ahead of the vehicle. The example method also includes calculating an effective weight of the vehicle based on (i) vehicle dynamics data and (ii) the connection status of the trailer; and the example method also includes adjusting a throttle based on the effective weight of the vehicle and a grade of the slope to maintain a set speed when the vehicle is traversing the slope 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a better understanding of the invention, reference may be made to embodiments shown in the following drawings. The components in the drawings are not necessarily to scale and related elements may be omitted, or in some instances proportions may have been exaggerated, so as to emphasize and clearly illustrate the novel features described herein. In addition, system components can be variously arranged, as known in the art. Further, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
         FIGS. 1A and 1B  illustrate a vehicle with a hill ascent regulator in accordance with the teachings of this disclosure. 
         FIG. 2  is a block diagram illustrating electronic components of the vehicle of  FIGS. 1A and 1B . 
         FIG. 3  is a block diagram of the hill ascent regulator of  FIG. 1 . 
         FIG. 4  is a flowchart of an example method to assist ascending a hill that may be implemented by the electronic components of  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS 
     While the invention may be embodied in various forms, there are shown in the drawings, and will hereinafter be described, some exemplary and non-limiting embodiments, with the understanding that the present disclosure is to be considered an exemplification of the invention and is not intended to limit the invention to the specific embodiments illustrated. 
       FIGS. 1A and 1B  illustrate a vehicle  100  with a hill ascent regulator  102  in accordance with the teachings of this disclosure. The hill ascent regulator  102  anticipates the changes in torque to maintain a current speed of the vehicle. The vehicle  100  is any type of road vehicle (e.g., cars, trucks, motorcycles, mopeds, etc.). The vehicle  100  may be a standard gasoline powered vehicle, a hybrid vehicle, an electric vehicle, a fuel cell vehicle, or any other type of suitable vehicle. The vehicle  100  includes a powertrain with an engine  104 , a transmission (not shown), a suspension (not shown), a driveshaft  106 , and wheels  108 . The powertrain generates power via the engine  104  and manages the power as the power is delivered to the wheels  108 . The vehicle  100  also includes standard features (not shown) such as a dashboard, adjustable seats, one or more batteries, an HVAC system including a compressor and electronic expansion valve, a windshield, doors, windows, seatbelts, airbags, and tires. 
     In some examples, the vehicle  100  includes a hitch  110  that allows a trailer  112  to be physically coupled to the vehicle  100 . The hitch  110  includes a hitch connector  114  that facilitates the trailer  112  being communicatively coupled to a control area network (CAN) bus (described below) of the vehicle  100 . When the trailer  112  is connected to the CAN bus via the hitch connector  114 , the vehicle  100  can control the systems of the trailer  112 , such as lights, brakes, and stability control, etc. In the illustrated example of  FIGS. 1A and 1B , the trailer  112  is coupled to the vehicle  100 . The hill ascent regulator  102  also anticipates the changes in the torque to maintain the current speed of the vehicle when the trailer  112  is not coupled to the vehicle  100 . 
     In the illustrated example, the vehicle  100  is driving on a road  116  that has a slope  118  (sometimes referred to as a gradient or a pitch). The slope  118  is measured in an angle of inclination compared to the horizon or a grade, which is a hundred times the tangent of the angle of inclination compared to the horizon. The slope may be upwards (the angle of inclination and the grade are positive) or the slope may be downwards (the angle of inclination and the grade are negative). In the example illustrated in  FIG. 1A , the road  116  is flat (that is, the grade of the slope  118  is zero). In the example illustrated in  FIG. 1B , the slope  118  of the road  116  is not flat. For example, the slope  118  of the road  116  may have a grade of forty. The gradient of the slope  118  may change such that the torque to maintain the current speed changes. 
     The vehicle  100  includes throttle-by-wire and/or cruise control. The cruise control facilitates the driver setting a desired speed, and maintains the set speed. The cruise control receives speed data from sensor(s) (such as a speedometer, a wheel speed sensor, etc). The cruise control uses the speed data to calculate the electronic signal to send to the throttle control  120  in order to maintain the set speed. As disclosed in more detail below, in an example embodiment, the hill ascent regulator  102  anticipates changes in torque to maintain the current speed while traversing the slope  118  of the road  116  ahead of the vehicle  100 . In some examples, the hill ascent regulator  102  also anticipates changes in the torque to maintain the current speed when the slope  118  of the road  116  ahead of the vehicle  100  changes from a negative gradient to a relatively flat gradient. The hill ascent regulator  102  instructs the throttle control  120  to adjust the torque supplied by the engine  104  before the vehicle  100  reaches in the change in the slope  118 . In such a manner, when the vehicle  100  reaches change in the slope  118 , the cruise control maintains the set speed. In some example embodiments, the hill ascent regulator  102  is part of the cruise control. Alternatively, in some embodiments, the hill ascent regulator  102  is separate from the cruise control. 
     Additionally, throttle-by-wire uses one or more sensors in conjunction with an acceleration pedal  122  to convert a mechanical force applied to the acceleration pedal  122  to an electrical signal. The mechanical force is measured by how far the acceleration pedal  122  is pushed. A throttle control  120  uses the electrical signal to control the throttle. The throttle regulates an amount of air that enters the engine  104 , which controls the power generated by the engine  104 . The throttle control  120  may dynamically change the mechanical-force-to-throttle ratio to, for example, control the how responsive the acceleration pedal  122  feels when a driver presses it. For example, a higher mechanical-force-to-throttle ratio feels more sluggish, and a lower higher mechanical-force-to-throttle ratio feels more sensitive. As disclosed in more detail below, in an example embodiment, the hill ascent regulator  102  anticipates changes in torque required to maintain a current speed when the gradient of the road is going to change and instructs the throttle control  120  to adjust the mechanical-force-to-throttle ratio to assist the driver while not requiring the driver to adjust the position of the acceleration pedal  122 . 
       FIG. 2  is a block diagram illustrating electronic components  200  of the vehicle  100  of  FIG. 1 . The electronic components  200  include an example on-board communications platform  202 , an example infotainment head unit  204 , an on-board computing platform  206 , example sensors  208 , example electronic control units (ECUs)  210 , a vehicle data bus  212 , and a controller area network (CAN) bus  214 . 
     The on-board communications platform  202  includes wired or wireless network interfaces to enable communication with external networks. The on-board communications platform  202  also includes hardware (e.g., processors, memory, storage, antenna, etc.) and software to control the wired or wireless network interfaces. In the illustrated example, the on-board communications platform  202  includes a Bluetooth® controller  216 , a GPS receiver  218 , and a DSRC controller  220 . The on-board communications platform  202  may also include controllers for other standards-based networks (e.g., Global System for Mobile Communications (GSM), Universal Mobile Telecommunications System (UMTS), Long Term Evolution (LTE), Code Division Multiple Access (CDMA), WiMAX (IEEE 802.16m); Near Field Communication (NFC); local area wireless network (including IEEE 802.11 a/b/g/n/ac or others), and Wireless Gigabit (IEEE 802.11ad), etc.). Further, the external network(s) may be a public network, such as the Internet; a private network, such as an intranet; or combinations thereof, and may utilize a variety of networking protocols now available or later developed including, but not limited to, TCP/IP-based networking protocols. The on-board communications platform  202  may also include a wired or wireless interface to enable direct communication with an electronic device (such as a smart phone, a tablet computer, a laptop, etc.). 
     The infotainment head unit  204  provides an interface between the vehicle  100  and a user (e.g., a driver, a passenger, etc.). The infotainment head unit  204  includes digital and/or analog controls (e.g., input devices and output devices) to receive input from the user(s) and display information. The input devices may include, for example, a control knob, an instrument panel, a digital camera for image capture and/or visual command recognition, a touch screen, an audio input device (e.g., cabin microphone), buttons, or a touchpad. The output devices may include instrument cluster outputs (e.g., dials, lighting devices), actuators, a display (e.g., a liquid crystal display (“LCD”), an organic light emitting diode (“OLED”) display, a flat panel display, a solid state display, or a heads-up display), and speakers. 
     The on-board computing platform  206  includes a processor or controller  224 , memory  226 , and storage  228 . The processor or controller  224  may be any suitable processing device or set of processing devices such as, but not limited to: a microprocessor, a microcontroller-based platform, a suitable integrated circuit, or one or more application-specific integrated circuits (ASICs). The memory  226  may be volatile memory (e.g., RAM, which can include non-volatile RAM, magnetic RAM, ferroelectric RAM, and any other suitable forms); non-volatile memory (e.g., disk memory, FLASH memory, EPROMs, EEPROMs, memristor-based non-volatile solid-state memory, etc.), unalterable memory (e.g., EPROMs), and read-only memory. In some examples, the memory  226  includes multiple kinds of memory, particularly volatile memory add non-volatile memory. The storage  228  may include a hard drive; a solid state hard drive; or a physical disk such as a DVD. 
     The memory  226  and the storage  228  are a computer readable medium on which one or more sets of instructions, such as the software for operating the methods of the present disclosure can be embedded. The instructions may embody one or more of the methods or logic as described herein. In a particular embodiment, the instructions may reside completely, or at least partially, within any one or more of the memory  226 , the computer readable medium, and/or within the processor  224  during execution of the instructions. 
     The term “computer-readable medium” should be understood to include a single medium or multiple media, such as a centralized or distributed database, and/or associated caches and servers that store one or more sets of instructions. The term “computer-readable medium” also includes any tangible medium that is capable of storing, encoding or carrying a set of instructions for execution by a processor or that cause a system to perform any one or more of the methods or operations disclosed herein. As used herein, the term “computer readable medium” is expressly defined to include any type of computer readable storage device and/or storage disk and to exclude propagating signals. 
     The sensors  208  may be arranged in and around the vehicle  100  in any suitable fashion. The sensors  208  may include camera(s), sonar, LiDAR, radar, optical sensors, or infrared devices configured to measure properties around the exterior of the vehicle  100 . Additionally, some sensors  208  may be mounted inside the passenger compartment of the vehicle  100 , in the engine compartment of the vehicle  100 , and on or around the powertrain of the vehicle  100  to measure properties in the interior of the vehicle  100 . For example, such sensors  208  may include accelerometers, wheel tachometers, yaw rate sensors, cameras, microphones, and thermistors, etc. 
     The ECUs  210  monitor and control the low-level systems of the vehicle  100 . For example, the ECUs  210  may control and/or monitor the lighting system, the engine, the power locks, the power windows, the power train, the HVAC system, and the battery management, etc. In the illustrated example, the ECU(s) include the electronic horizon unit, the throttle control  120 , and cruise control. The ECU(s) communicate properties to and/or receive commands from the on-board computing platform  206 . 
     The vehicle data bus  212  communicatively couples the on-board communications platform  202 , the infotainment head unit  204 , and the on-board computing platform  206 . The vehicle data bus  212  may be an Ethernet network. The CAN bus  214  communicatively couples the sensors  208 , the ECUs  210 , the on-board computing platform  206 , and other devices connected to the CAN bus  214 . The CAN bus protocol is defined by International Standards Organization (ISO) 11898-1. In some examples, the on-board computing platform  206  communicatively isolates the vehicle data bus  212  and the CAN bus  214  (e.g., via firewalls, message brokers, etc.). Alternatively, in some examples, the vehicle data bus  212  and the CAN bus  214  may be the same data bus. 
       FIG. 3  is a block diagram of the hill ascent regulator  102  of  FIG. 1 . The hill ascent regulator  102  is configured to (i) anticipate changes in torque to maintain the speed of the vehicle when the gradient of the road is going to change, and (ii) adjust the throttle and/or the powertrain control to supply the torque before the gradient of the road changes. The hill ascent regulator  102  includes (a) a trailer connection detector  300  configured to detect when a trailer  112  is connected, via the hitch  110 , to the vehicle  100 ; (b) a road geometry component  302  configured to determine the slope  118  of an upcoming part of the road  116  on which the vehicle  100  is driving; (c) a vehicle payload component  304  configured to determine an effective Gross Vehicle Weight (GVW) (or Gross Vehicle Mass (GVM)) of the vehicle  100 ; and (d) a throttle adjuster  306  configured to adjust a throttle of the vehicle  100  based on the effective GVW/GVM to maintain the speed of the vehicle  100 . 
     The trailer connection detector  300  of the hill ascent regulator  102  detects when the trailer  112  is connected to the hitch  110  of the vehicle  100 . When the trailer  112  is connected, the hitch connector  114  sends a message on the CAN bus  214 . The trailer connection detector  300  detects the message on the CAN bus  214 . In some examples, the trailer  112  also communicates information about the trailer  112  on the CAN bus  214 , such as the GVW/GVM of the trailer  112 . 
     The road geometry component  302  of the hill ascent regulator  102  receives map data representative of the characteristics of the road on which the vehicle  100  is driving from an electronic horizon unit. The map data includes information of the road  116  up to a distance ahead (such as one kilometer or 0.62 miles) of the current location of the vehicle  100 . For example, the map data may include turn angles, road gradients, road features (such as tunnels, bridges, etc.), and positions (e.g., coordinates from a global positioning system (GPS), and speed limits, etc), etc. In certain example embodiments, the road geometry component  302  receives the map data from the electronic horizon unit which is compatible with the Advanced Driver Assistance Systems (ADAS) protocol maintained by the ADASIS Forum. More information on the ADAS protocol is available in the “ADAS Protocol for Advanced In-Vehicle Applications” (available at http://durekovic.com/publications/documents/ADASISv2%20ITS%20NY%20Paper%20Final.pdf), which is hereby incorporated by reference in its entirety. The road geometry component  302  uses the map data to determine slope data, which includes: (a) whether there is a change in the road gradient ahead of the vehicle  100 ; (b) the slope of the change in the road gradient; and (c) if within the range of the map data, the crest of the slope. For example, the road geometry component  302  may determine that there is a slope with a 20% grade (11.31 degree angle) 250 meters (0.16 miles) ahead of the vehicle  100  that crests after 500 meters (0.31 miles). 
     The vehicle payload component  304  of the hill ascent regulator  102  receives vehicle dynamics data from the sensors  208  and/or the ECUs  210  of the vehicle  100 . The vehicle dynamics data includes a base GVM/GVM (the GVM/GVM as built in the factory) for the vehicle  100 , the speed of the vehicle  100 , fuel level data, the torque applied to the wheels  108 , and the pitch and yaw of the vehicle  100 , etc. The vehicle payload component  304  also receives trailer connection data from trailer connection detector  300  indicating whether the trailer  112  is attached. The vehicle payload component  304  calculates the effective GVW/GVM of the vehicle  100  based on the vehicle dynamics data, the trailer connection data, and a vehicle model. The effective GVW/GVM is the GVW/GVM of the vehicle  100  plus other factors (such as aerodynamic drag, inertia, rolling resistance of the tires, etc.) that affect what torque to apply to the wheels  108  of the vehicle  100  to maintain the current speed. In some examples, even when the trailer  112  is not connected, passengers and/or cargo in the vehicle  100  may weight enough to affect the vehicle dynamics data, and thus affect the calculation of the effective GVW/GVM of the vehicle. For example, a vehicle  100  with thirty cinder blocks as cargo would need more torque than the same vehicle  100  with just a driver. In some examples, when the trailer connection detector  300  indicates that the trailer  112  is connected, the vehicle payload component  304  includes the GVW/GVM of the trailer  112  when calculating the effective GVW/GVM. The vehicle model provides a relationship of the vehicle dynamics data and the GVW/GVM of the vehicle  100  to the effective GVW/GVM. For example, the model may be based on a calculated expected torque to move the vehicle  100  with the base GVW/GVM and a full fuel tank. In such an example, deviations between the expected torque and the actual torque to move the vehicle  100 , as measured by the vehicle dynamics data, are used to calculate the effective GVW/GVM. 
     The throttle adjuster  306  of the hill ascent regulator  102  sends instructions to (i) the throttle control  120  to adjust the throttle and/or (ii) a powertrain control  124  to adjust the torque applied to the wheels  108 . The throttle adjuster  306  receives the slope data from the road geometry component  302  and the effective GVW/GVM from the vehicle payload component  304 . The throttle adjuster  306  supplies (a) the effective GVW/GVM and (b) the slope data to a torque demand model (sometimes referred to as an “engine torque map”). The torque demand model relates the torque delivered by the engine  104  to the speed of the engine  104  and the position of the throttle. The torque demand model determines the torque to be applied to the wheels to maintain the current speed of the vehicle  100  while traversing the slope  118 . The torque demand model uses the effective GVW/GVM and the speed modify to a torque demand curve to determine the torque to maintain and/or accelerate to that speed. The slope data shifts the torque demand curve to affect the torque to maintain and/or accelerate to that speed. For example, if the vehicle  100  is traveling on a flat road (such as the road  116  in  FIG. 1A ) at 63 kilometers per hour (kph) (40 miles per hour (mph)), the torque demand model produces a first torque demand value. In that example, if the vehicle  100  is traveling on a 40 grade rode (such as the road  116  of  FIG. 1B ) at 63 kph, the torque demand model produces a second torque demand value higher than the first torque demand value. The effective GVW/GVM also affects the torque demand curve. 
     The throttle adjuster  306  begins to instruct the throttle control  120  to adjust the torque produced by the engine  104  and/or the powertrain control  124  to adjust the torque on the wheels  108  before the vehicle  100  reaches the slope  118  so that when the vehicle  100  reaches the slope  118 , the vehicle  100  (a) has sufficient torque to ascend the slope  118  without slowing down, or (b) has sufficient torque to maintain the current speed when the road  116  changes from the slope  118  to be relatively flat. For example, the throttle adjuster  306  may start gradually increasing the throttle and/or the powertrain 150 meters (0.09 miles) before the vehicle reaches the slope  118  detected by the road geometry component  302 . 
       FIG. 4  is a flowchart of an example method to assist ascending a hill that may be implemented by the electronic components  200  of  FIG. 2 . Initially, the trailer connection detector  300  determines whether the trailer  112  is connected to the vehicle  100  (block  402 ). For example, the trailer connection detector  300  may detect a signal sent from the trailer  112  on the CAN bus  214 . The vehicle payload component  304  determines the effective GVW/GVM of the vehicle  100  (block  404 ). For example, the vehicle payload component  304  may use the vehicle model to determine effective GVW/GVM of the vehicle  100  based on whether the trailer  112  is connected, the GVW/GVM of the vehicle  100 , and the vehicle dynamics data received from sensors  208 . 
     The road geometry component  302  determines the slope  118  of the road  116  ahead of the vehicle  100  (block  406 ). The road geometry component  302  receives map data for a distance (such as 250 meters, (0.16 miles), 500 meters (0.31 miles), etc.) ahead of the vehicle  100  to determine the slope  118  of the road  116 . For example, the road geometry component  302  may determine that the slope  118  of the road  116  has a grade of five for the next 250 meters ahead of the vehicles and a grade of twenty after 250 meters. The road geometry component  302  determines whether a detected change of the slope  118  is positive (block  408 ). For example, if the grade of the road  116  changes from the grade of five to the grade of twenty, the road geometry component  302  determines the change of the slope  118  is positive. As another example, if the grade of the road  116  changes from the grade of twenty to the grade of five, the road geometry component  302  determines the change of the slope  118  is negative. If the change of the slope  118  is negative, the road geometry component  302  continues to determine the slope  118  of the road  116  ahead of the vehicle  100  (block  406 ). 
     If the change of the slope  118  is positive, the throttle adjuster  306  calculates acceleration to maintain the current speed (block  410 ). The throttle adjuster  306  calculates acceleration to maintain the current speed based on the torque demand model. The torque demand model calculates the torque to maintain the current speed when the vehicle  100  is ascending the slope  118  based on the effective GVW/GVM of the vehicle  100  from the vehicle payload component  304  and the slope  118  determined by the road geometry component  302 . In some example embodiments, the throttle adjuster  306  determines when to start the acceleration based on (i) the change in the grade of the slope  118  and/or (ii) an acceptable increase in the RPM of the engine  104  when the vehicle  100  is ascending the slope  118 . For example, to ascend a first slope  118 , the throttle adjuster  306  may gradually increase the power provided by the engine  104  for 130 meters. As another example, to ascend a second slope  118  with a higher grade than the first slope, the throttle adjuster  306  may gradually increase the power provided by the engine  104  for 235 meters. The throttle adjuster  306  sends a signal to the throttle control  120  to adjust the throttle based on the acceleration calculated at block  410  (block  412 ). In some example embodiments, the throttle adjuster  306  may send multiple signals to gradually increase the torque supplied by the engine  104 . The road geometry component  302  then continues to determine the slope  118  of the road  116  ahead of the vehicle  100  (block  406 ). 
     In this application, the use of the disjunctive is intended to include the conjunctive. The use of definite or indefinite articles is not intended to indicate cardinality. In particular, a reference to “the” object or “a” and “an” object is intended to denote also one of a possible plurality of such objects. Further, the conjunction “or” may be used to convey features that are simultaneously present instead of mutually exclusive alternatives. In other words, the conjunction “or” should be understood to include “and/or”. 
     The above-described embodiments, and particularly any “preferred” embodiments, are possible examples of implementations and merely set forth for a clear understanding of the principles of the invention. Many variations and modifications may be made to the above-described embodiment(s) without substantially departing from the spirit and principles of the techniques described herein. All modifications are intended to be included herein within the scope of this disclosure and protected by the following claims.