Information display system for transmitting regenerative braking and friction braking values

Abstract

Information display system (66) comprising: a regenerative braking indicator including a regenerative braking indicator corresponding to a current regenerative braking value and a static regenerative braking threshold (82) corresponding to a regenerative braking threshold value; and a control system configured to: Receiving at least one input relating to current operating conditions of a vehicle (10), Determining the regenerative braking threshold based on the current operating conditions, and Providing at least one output to the regenerative braking indicator to position the regenerative braking indicator based on the current regenerative braking value and the regenerative braking threshold relative to the regenerative braking threshold (82), wherein the regenerative braking threshold is dynamic, characterized in that the regenerative braking threshold is a minimum of a powertrain braking limit and an electric battery charging system limit.

Description

TECHNICAL FIELD

[0001] The present application relates to an information display system including a split display instrument for communicating regenerative braking and friction braking values. BACKGROUND

[0002] All vehicles, whether passenger or commercial, contain a number of gauges, indicators, and various other displays to provide the vehicle operator with information regarding the vehicle and its surroundings. With the advent of new technologies such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs), a variety of new gauges and information displays have emerged to help guide drivers in better learning, understanding, and operating these vehicles that utilize new technology. For example, many HEVs contain gauges that attempt to provide the driver with information about the various hybrid driving modes. Some gauges tell the driver when the vehicle is being propelled by the engine alone, the motor alone, or a combination of both.Similarly, an indicator can indicate when the engine is operating as a generator and recharging an energy storage device such as a battery.

[0003] It is known that some drivers, partly due to driving habits, may be unable to achieve desired fuel economy or energy efficiency figures. In many cases, drivers are willing to change their behavior but are unable to translate recommended techniques into actual changes in their driving habits. With the increase in sensing electronics, computers, and other related technology onboard a vehicle, the amount of information that can be communicated to the driver is virtually unlimited. Often, the driver may not even be aware of all the features and capabilities their vehicle has to offer. Displaying certain types of information, particularly information relevant to HEVs, PHEVs, or BEVs, can help enable economical driving choices or habits. US Pat. No. 8,855,880 B2 discloses a method and system for displaying braking information. SUMMARY

[0004] An improvement over the prior art is achieved with the features of claim 1. Preferred embodiments thereof are specified in the further claims. The present application relates to an information display system for use in a motor vehicle with a regenerative braking system. In accordance with one or more embodiments, an information display system may include a regenerative braking indicator and a corresponding control system. The regenerative braking indicator may include a regenerative braking indicator corresponding to a current regenerative braking value and a static regenerative braking threshold corresponding to a regenerative braking threshold. The control system may receive at least one input related to current operating conditions of a vehicle and determine the regenerative braking threshold based on the current operating conditions.Further, the control system may provide at least one output to the regenerative braking indicator to position the regenerative braking indicator relative to the regenerative braking threshold based on the current regenerative braking value and the regenerative braking threshold.

[0005] In this regard, the regenerative braking threshold, although corresponding to a regenerative braking threshold, which may be dynamic, may remain at a fixed position. The regenerative braking indicator may move along the regenerative braking gauge based on its corresponding value and the current regenerative braking threshold. Thus, the amount of regenerative braking being used relative to the current maximum can be determined at a glance.

[0006] In accordance with one or more additional embodiments of the present application, a braking indicator for a vehicle may include a static first boundary, a static second boundary, and a braking indicator disposed between the first boundary and the second boundary. The braking indicator may further include a first region disposed between the braking indicator and the first boundary. The first region may correspond to a first braking percentage contributed by a first braking source. The braking indicator may further include a second region disposed between the braking indicator and the second boundary. The second region may correspond to a second braking percentage contributed by a second braking source.

[0007] Accordingly, the position of the braking indicator between the first limit and the second limit may indicate a current distribution of braking between the first braking source and the second braking source. The first braking source may be associated with a regenerative braking system, and the second braking source may be associated with a friction braking system.

[0008] Additionally, the present application relates to a method for displaying braking information to a driver of a vehicle. In accordance with one or more embodiments, the method includes displaying a braking indicator having a fixed first limit and a fixed second limit. The method further includes determining a regenerative braking amount and a friction braking amount to obtain a total braking amount. The method also includes displaying an indicator disposed between the first and second limits. The indicator may be positioned relative to the first and second limits to indicate the regenerative braking amount relative to the total braking amount when the regenerative braking amount and the friction braking amount are greater than zero. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a simplified exemplary schematic diagram of a vehicle including an information display system in accordance with one or more embodiments of the present application; Fig. 2(a) illustrates an exemplary information display including a brake indicator conveying a first brake mode, in accordance with one or more embodiments of the present application; Fig. 2(b) shows an exemplary information display including a brake indicator conveying a second brake mode, in accordance with one or more embodiments of the present application; Fig. 2(c) shows an exemplary information display including a brake indicator communicating a third brake mode, in accordance with one or more embodiments of the present application; Fig. 2(d) shows an exemplary information display including a brake indicator conveying a fourth brake mode, in accordance with one or more embodiments of the present application; Fig. 3(a) shows another exemplary information display including an alternative brake indicator conveying a first brake mode, in accordance with one or more embodiments of the present application; Fig. 3(b) shows another exemplary information display including an alternative brake indicator conveying a second brake mode, in accordance with one or more embodiments of the present application; and Fig. 3(c) shows another exemplary information display including an alternative brake indicator conveying a third brake mode, in accordance with one or more embodiments of the present application. DETAILED DESCRIPTION

[0009] As required, detailed embodiments of the present invention are disclosed herein; however, it should be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Thus, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching those skilled in the art to variously utilize the present invention.

[0010] Now in the drawings is Fig. 1 is a simplified exemplary schematic representation of a vehicle 10 that may include an engine 12 and an electric machine or generator 14. The engine 12 and generator 14 may be connected via a power transfer arrangement, which in this embodiment is a planetary gear assembly 16. Of course, other types of power transfer arrangements, including other gear sets and transmissions, may be used to connect the engine 12 to the generator 14. The planetary gear assembly 16 includes a ring gear 18, a carrier member 20, planet gears 22, and a sun gear 24.

[0011] The generator 14 may also output torque to a shaft 26 connected to the sun gear 24. Similarly, the engine 12 may output torque to a crankshaft 28, which may be connected to a shaft 30 via a passive clutch 32. The clutch 32 may provide protection against over-torque conditions. The shaft 30 may be connected to the carrier 20 of the planetary gear assembly 16, and the ring gear 18 may be connected to a shaft 34, which may be connected to a first set of vehicle drive gears or primary drive gears 36 via a gear set 38.

[0012] The vehicle 10 may include a second electric machine or motor 40 that may be used to output torque to a shaft 42 connected to the gear set 38. Other vehicles within the scope of the present application may have other arrangements of electric machines, such as more or fewer than two electric machines. In the Fig. In the embodiment shown in FIG. 1, the assembly of both electric machines (i.e., the engine 40 and the generator 14) can be used as motors for outputting torque. Alternatively, each can be used as a generator, outputting electrical power to a high-voltage bus 44 and to an energy storage system 46, which may include a battery 48 and a battery control module (BCM) 50.

[0013] The battery 48 may be a high-voltage battery capable of outputting electrical power to operate the motor 40 and the generator 14. The BCM 50 may act as a controller for the battery 48. Other types of energy storage systems may be used within a vehicle, such as the vehicle 10. For example, a device such as a capacitor may be used, which, like a high-voltage battery, can both store and output electrical energy. Alternatively, a device such as a fuel cell may be used in conjunction with a battery and / or capacitor to provide electrical power to the vehicle 10.

[0014] As in Fig. 1, the motor 40, the generator 14, the planetary gear assembly 16, and a portion of the second gear set 38 may be generally referred to as a transmission 52. To control the engine 12 and components of the transmission 52 (i.e., the generator 14 and the motor 40), a vehicle computer system may be provided, shown generally as a vehicle controller 54. Although shown as a single controller, it may include or represent multiple controllers that may be used to control various vehicle systems or components. The controller 54 may include, for example, a vehicle system controller / powertrain control module (VSC / PCM). In this regard, the PCM portion of the VSC / PCM may be software embedded within the VSC / PCM or may be a separate hardware device.

[0015] A Controller Area Network (CAN) 56 may enable the controller 54 to communicate with the transmission 52 and with the BCM 50. Just as the battery 48 includes a BCM 50, other devices controlled by the controller 54 may have their own controllers. For example, an engine control unit (ECU) may communicate with the controller 54 and perform control functions on the engine 12. In addition, the transmission 52 may include a transmission control module (TCM) configured to coordinate the control of specific components within the transmission 52, such as the generator 14 and / or the motor 40. Some or all of these various controllers may constitute a control system in accordance with the present application.Although illustrated and described in the context of vehicle 10, which is an HEV, embodiments of the present application may, of course, be implemented on other types of vehicles, such as those powered by an internal combustion engine alone, by an electric motor alone, by a fuel cell, or the like.

[0016] In addition, Fig. 1, simplified schematic representations of a braking system 58 and an accelerator pedal 60 are shown. The braking system 58 may include such things as a brake pedal, position sensors, pressure sensors, or a combination thereof (not shown), as well as a mechanical connection to the vehicle wheels, such as wheels 36, to provide friction braking via a friction braking system 62. Additionally, the braking system 58 may include a regenerative braking system 64 in which braking energy is captured and stored as electrical energy in the battery 48. Similarly, the accelerator pedal 60 may include one or more sensors that, like the sensors in the braking system 58, may communicate with the controller 54.

[0017] In addition to the foregoing, the vehicle 10 may include an information display system 66 that, as explained in detail below, may provide relevant vehicle content to the driver of the vehicle 10. As in Fig. 1, the information display system 66 may include an information display 68. Additionally, the information display system 66 may include its own display control system, which for reference purposes may be the controller 54. Although shown as the controller 54, the display control system may include a separate display control module that, similar to the BCM 50, communicates with the main vehicle controller 54 and performs control functions on the information display 68. The controller 54 may be configured to receive input related to current operating conditions of the vehicle 10. Furthermore, the controller 54, acting as a display control system, may provide an output such that the information display 68 communicates driving or braking efficiency information or other information related to the operation of the vehicle 10 to the driver.

[0018] The information display 68 may be disposed within an instrument panel (not shown) of the vehicle 10, such as an instrument panel or a center console area. Furthermore, the information display 68 may be part of another display system, such as a navigation display system, or part of a dedicated information display system. The information display 68 may be a liquid crystal display (LCD), a plasma display, an organic light emitting display (OLED), or other suitable display. The information display 68 may include a touchscreen for receiving driver input associated with selected areas of the information display 68. Furthermore, the information display system 66 may include one or more push buttons (not shown), such as hard keys or soft keys, disposed adjacent to the information display 68 for effecting driver input.Other operator inputs known to one of ordinary skill in the art may also be used without departing from the scope of the present application.

[0019] Generally based on Fig. 2(ad), the information display 68 is shown in more detail in accordance with one or more embodiments of the present application. As can be seen there, the information display 68 may include a brake indicator 70 that may communicate braking efficiency information to a driver. The braking efficiency information communicated by the brake indicator 70 may help the driver maximize energy capture during a braking event in vehicles with a regenerative braking system, such as the vehicle 10. To this end, the brake indicator 70 may be a split-power (or split-torque) brake indicator that may include a regenerative braking indicator section 72 and a friction braking indicator section 74. As shown in Fig. 2(ad), the regenerative braking gauge section 72 and the friction braking gauge section 74 may be adjacent to each other, for example, in a side-by-side configuration. Furthermore, the regenerative braking gauge section 72 and the friction braking gauge section 74 may be linear gauges, as shown. Other gauge arrangements may also be used.

[0020] Now specifically in Fig. 2(a) shows an example of the brake indicator 70 during a braking event condition in accordance with one or more embodiments of the present application. The particular Fig. The example given in Figure 2(a) shows the brake gauge 70 in a pure regenerative braking state (i.e., all regenerative braking), such as may often occur at the beginning of a braking event. As seen there, the regenerative braking gauge portion 72 may include a first limit 76 and a second limit 78. Further, the regenerative braking gauge portion 72 may include a regenerative braking indicator 80 associated with a regenerative braking value and a regenerative braking threshold 82 associated with a regenerative braking threshold. The first limit 76 may correspond to a lower limit, which in one or more embodiments may be approximately equal to zero. The regenerative braking threshold 82 may be fixed at the second limit 78.Thus, the regenerative braking indicator 80 may be movable between the first limit 76 and the regenerative braking threshold 82 based on the regenerative braking value. In this regard, the regenerative braking threshold 82 may be static, while the regenerative braking indicator 80 is dynamic. Although the regenerative braking threshold 82 may be fixed at the second limit 78 in accordance with one or more embodiments, the regenerative braking threshold itself may vary. Accordingly, the regenerative braking indicator 80 may provide an indication of the current regenerative braking value relative to the current regenerative braking threshold.

[0021] In accordance with one or more alternative embodiments, the regenerative braking threshold 82 may be dynamically positioned between the first limit 76 and the second limit 78. In this regard, the regenerative braking threshold 82 may move in accordance with the regenerative braking threshold. Furthermore, the regenerative braking indicator 80 may indicate an actual regenerative braking value, rather than a value merely relative to the regenerative braking threshold, such as a percentage.

[0022] Back in Fig. 2(a), the regenerative braking indicator 80 may define a bar segment extending from the first boundary 76 toward the second boundary 78 to help indicate the regenerative braking value, particularly relative to the regenerative braking threshold associated with the regenerative braking threshold 82. Similar to the regenerative braking portion 72, the friction braking portion 74 also includes a first boundary 76' and a second boundary 78'. Likewise, the first boundary 76' may correspond to a lower limit, which in one or more embodiments may be approximately equal to zero. Furthermore, a friction braking threshold 84 associated with a maximum friction braking value may be fixedly located at the second boundary 78'.The maximum friction braking value may be a calibratable maximum value obtained from calibratable tables stored in a storage device (not shown) of the information display system 66 (e.g., in the controller 54). This may allow for nonlinear, tunable behavior of the friction braking system 62.

[0023] In addition, the friction brake gauge section 74 may include a friction brake indicator 86 (best in Fig. 2(b)-(d)) associated with a friction braking value. The friction braking indicator 86, like the regenerative braking indicator 80, may be movable between the first boundary 76' and the friction braking threshold 84 based on the friction braking value. If, as shown in Fig. 2(a), during a braking event only regenerative braking is used, the friction brake indicator 86 may be located at the first boundary 76' or may not be displayed at all.

[0024] In accordance with one or more embodiments of the present application, the regenerative braking values and the friction braking values may be power values. Alternatively, the braking values associated with the indicators and thresholds may be torque-based. The controller 54 may receive one or more inputs related to current vehicle operating conditions. For example, the controller 54 may receive input signals corresponding to vehicle speed, accelerator and / or brake pedal position, battery charge limits, torque limits, and the like. The controller 54 may determine at least the regenerative braking threshold value, the regenerative braking value, the friction braking value, and a total braking value based on the at least one input.

[0025] In a power-based system, the total braking value Pt, which includes both regenerative braking and friction braking, can be calculated using the following general equation: Pt=(Tr+Tf)⋅Vsp where:T r = recovery torque, T f = friction torque and V sp = vehicle speed.

[0026] The recovery torque T r can refer to the proportion of the total torque applied by regenerative braking. The friction torque T f , can refer to the portion of the total torque applied by friction.

[0027] As a more specific example, the total braking power value Pt can be calculated in accordance with the following equation: Pt=(Tar+Tbsm+Tf)⋅SmRmw where: T ar = accelerator pedal torque request, T bsm= Brake system torque change T f = friction torque, S m = engine torque and R mw = Motor-wheel gear ratio.

[0028] The accelerator pedal torque request T ar can refer to the torque requested by a driver via the accelerator pedal, which can be either positive or negative. The brake system torque change T bsm can refer to the amount of braking torque added by the powertrain over and above that requested by the accelerator pedal. The engine speed S m can refer to the speed of the motor 40. The motor-to-wheel gear ratio R mw may refer to the relationship between the wheels 36 and the engine 40.

[0029] As previously described, the regenerative braking threshold may be dynamic and thus vary with changes in current vehicle operating conditions. In accordance with one or more embodiments of the present application, the regenerative braking threshold may be the minimum of either (1) the powertrain braking torque limit multiplied by the vehicle speed, or (2) the power limit of the battery 48 electrical charging system. More specifically, the regenerative braking threshold P r,thresh can be calculated using the following equation: Pr,thresh=min[(Tl⋅smRmw),Pl,batt] where: T I = the driveline braking torque limit, S m = the engine speed, R mw = the engine-wheel gear ratio and P l,batt = the performance limit of the electrical battery charging system.

[0030] Thus, the amount of regenerative braking can be limited by the vehicle powertrain's ability to apply negative torque (i.e., the powertrain braking torque limit T I ) or by the amount of additional charge that the battery 48 can accept in its current state (i.e., the power limit of the electrical battery charging system P l,batt ), be limited. The power limit of the electric battery charging system P l,batt can be influenced by the charge level, temperature and the like.

[0031] In accordance with one or more embodiments, the regenerative braking value P r can be calculated using the following general equation: Pr=Tr⋅Vsp where: T r = Regeneration torque and V sp = vehicle speed.

[0032] As a more specific example, the regenerative braking value P r be calculated in accordance with the following equation: Pr=(Tar+Tbsm)⋅SmRmw where: T ar = accelerator pedal torque request, T bsm = brake system torque change, S m = engine speed and R mw = Motor-wheel gear ratio.

[0033] In accordance with one or more embodiments, the friction braking value P f can be calculated using the following general equation: Pf=Tf⋅Vsp where: T f = friction torque and V sp = vehicle speed.

[0034] As a more specific example, the friction braking value P f be calculated in accordance with the following equation: Pf=Tf⋅SmRmw where: T f= friction torque, S m = engine speed and R mw = Motor-wheel gear ratio.

[0035] As previously described, the regenerative braking threshold 82 may be fixed at the second limit 78, although the regenerative braking threshold itself may vary. Accordingly, the regenerative braking indicator 80 may indicate the current regenerative braking value relative to the current regenerative braking threshold. In other words, the regenerative braking indicator 80 may be positioned between the first limit 76 and the regenerative braking threshold 82 based on the ratio between the regenerative braking value and the regenerative braking threshold. The ratio may, of course, be expressed as a percentage. For this purpose, the regenerative braking percentage for the display P r(%)can be calculated using the following general equation: Pr(%)=PrPr,thresh⋅100

[0036] Similarly, the current friction braking value can be expressed as a percentage of the maximum friction braking value using the friction braking indicator 86. For example, the current friction braking value can be mapped from 0% to 100% for display purposes, where 0% corresponds to zero friction braking and 100% corresponds to the calibratable maximum friction braking value represented by the friction braking threshold 84. As previously described, mapping the friction braking value to a friction braking percentage for display can be accomplished using calibratable tables to enable nonlinear, tunable behavior.

[0037] Although the above equations (1)-(8) correspond to power-based braking values, the equations for the brake indicator, which uses torque-based values, are similar. In particular, the torque-based equations can be simplified by removing the speed components from the power-based equations (e.g., V sp or S m / R mw ) and converting the power limit of the electrical charging system 48 into the torque range.

[0038] Fig. Figure 2(a) shows an example of the brake indicator 70 when the vehicle 10 is in a pure regenerative braking state (i.e., all regenerative braking), as often occurs at the beginning of a braking event. Thus, the friction braking indicator 86 may be absent or positioned at the first boundary 76' to indicate that no friction braking is occurring. As shown in Fig. 2(a), the regenerative braking indicator 80 has not reached the regenerative braking threshold 82. This may indicate that additional regenerative braking may still occur or that regenerative braking has not been fully optimized. Maximizing regenerative braking may lead to increased efficiency in vehicles equipped with energy storage devices that help power traction motors, such as BEVs and HEVs. By setting the regenerative braking threshold 82 at the second boundary 78, even though its corresponding regenerative braking threshold may vary, the brake indicator instrument 70 may be less intrusive and easier to understand.This is particularly helpful and conducive to drivers who want to be informed of their braking performance at a glance at the brake indicator instrument 70 while driving, while maintaining their primary concentration on the road.

[0039] Fig. Figure 2(b) illustrates an example of the brake indicator 70 during a different state of a braking event in accordance with one or more embodiments of the present application. For example, during a braking event, if the total braking demand exceeds the amount of braking that can be supplied by the regenerative braking system 64 (i.e., the regenerative braking threshold), the friction braking system 62 may be engaged to make up the difference. The particular Fig. The example given in Figure 2(b) shows the brake gauge 70 during a braking condition. As seen here, the regenerative braking indicator 80 may be displayed at the regenerative braking threshold 82 to indicate to a driver that the regenerative braking threshold has been reached. Accordingly, the friction braking indicator 86 may be displayed between the first boundary 76' and the friction braking threshold 84 to indicate that the friction brakes are being utilized. This may signal to a driver that inefficient braking is occurring because energy applied to the friction brakes is lost as heat. As previously described, the friction braking indicator 86 may be positioned relative to the friction braking threshold 84 in the friction braking gauge section 74 based on the current friction braking value and the maximum friction braking value.

[0040] As in Fig. As shown in Figure 2(b), regenerative braking may typically be at its threshold when friction braking is introduced during a braking event. However, in accordance with one or more embodiments of the present application, a mix of regenerative braking and friction braking may occur even though the regenerative braking level does not reach the regenerative braking threshold. Fig. Figure 2(c) illustrates an example of the brake indicator 70 during such a mixed braking condition. As can be seen therein, the regenerative braking indicator 80 may be displayed below the regenerative braking threshold 82 (indicating that the regenerative braking threshold has not been reached), while the friction braking indicator 86 indicates that some friction braking is taking place at the same time. A mixed braking condition, as shown in Fig. 2(c), may occur, for example, near the end of a braking event or at the beginning of a hard braking event. A hard braking event may occur when a strong pressure is applied to the brake pedal, signaling a relatively high braking demand (such as when a driver performs an emergency stop). As shown in Fig. Thus, as shown in Figure 2(c), the regenerative braking indicator 80 and the friction braking indicator 86 can move independently of each other. That is, when the regenerative braking indicator 80 has reached the regenerative braking threshold 82, the friction braking indicator 86 does not move alone.

[0041] Even if regenerative braking is not at its current maximum, friction braking may be introduced into the braking system 58 at lower vehicle speeds. In this way, friction braking may be introduced while regenerative braking is gradually discontinued. For reasons understood by those skilled in the art, regenerative braking may be Fig. 2(d), eventually be fully discontinued in a stepwise manner before the vehicle speed reaches zero. Thus, near the end of a braking event, a vehicle can be slowed to a complete stop using only friction braking.

[0042] In accordance with one or more embodiments of the present application, friction braking may begin to be blended with regenerative braking when the vehicle speed is below a first vehicle speed threshold. Furthermore, regenerative braking may be completely removed when the vehicle speed falls below a second vehicle speed threshold that is less than the first vehicle speed threshold. The vehicle may begin to gradually discontinue regenerative braking at the first vehicle speed threshold, such that regenerative braking is gradually reduced until it is gradually discontinued completely at the second vehicle speed threshold. Gradually discontinuing regenerative braking in this manner ensures a smoother transition from pure regenerative braking to pure friction braking.The indication of the friction brake indicator 86 between the first limit 76' and the friction brake threshold 84 when the regenerative brake indicator 80 is not at the regenerative brake threshold 82, as in . Fig. 2(c)-(d) can inform drivers that the occurrence of friction braking is not necessarily a result of inefficient braking on their part.

[0043] The Fig. 3(a)-(c) illustrate one or more alternative embodiments of the present application. In general, the Fig. 3(a)-(c) illustrate a brake indicator 90 for communicating braking information to a driver of the vehicle 10. Instead of two adjacent indicator sections, a single brake indicator section 92 may be used to communicate both regenerative braking information and friction braking information in a stacked configuration. The brake indicator 90 may include a first boundary 94 and a second boundary 96. Both the first and second boundaries may be static, such that their positions do not change. Furthermore, the brake indicator 90 may include a braking indicator 98 disposed between the first boundary 94 and the second boundary 96 during a braking event. Additionally or alternatively, a braking status indicator 100 may be disposed adjacent to the brake indicator section 92 to indicate the current state of braking.For example, the brake status indicator 100 may communicate whether the braking system 58 of the vehicle 10 is operating in a pure regenerative braking mode, a pure friction braking mode, or a mixed braking mode. In accordance with one or more embodiments, the brake status indicator 100 may be text displayed or illuminated based on the current braking state.

[0044] With specific reference to Fig. 3(a) illustrates an exemplary embodiment of the brake indicator 90 in a pure regenerative braking mode. As can be seen therein, the brake indicator 90 may include a first region 102 defined by the brake indicator 98 and the first boundary 94. In the pure regenerative braking mode, the second boundary 96 may be a regenerative braking threshold 104 corresponding to the regenerative braking threshold value. Furthermore, the brake indicator 98 may correspond to the regenerative braking value. In this regard, the brake indicator 90 may Fig. 3(a) similar to that in Fig. 2(a)-(d) when the regenerative braking value is less than the regenerative braking threshold and when the friction braking value is approximately equal to zero. Accordingly, the braking indicator 98 may indicate the current regenerative braking value relative to the current regenerative braking threshold. The braking indicator 98 may be positioned between the first limit 94 and the regenerative braking threshold 104 based on the ratio between the regenerative braking value and the regenerative braking threshold. The ratio may, of course, be defined as the regenerative braking percentage for the display, P r(%) as calculated using equation (8).

[0045] As in Fig. 3(a), the brake status indicator 100 may also indicate that the vehicle is in a regenerative braking only mode. The brake status indicator 100 may display, illuminate, or otherwise communicate the regenerative braking only mode. For example, the brake status indicator 100 may display the text "REGEN." The brake gauge 90 may also utilize other indicators. For example, regenerative braking may be associated with a particular color or shade of the brake indicator 98 and / or the first region 102. Thus, a driver may be alerted to the regenerative braking only mode if only the first region 102 is displayed in a color associated with regenerative braking.

[0046] Fig. 3(b) illustrates an exemplary embodiment of the brake indicator 90 in a mixed braking mode in accordance with one or more embodiments of the present application. As seen therein, the brake indicator 90 may further include a second region 106 disposed between the braking indicator 98 and the second boundary 96. The first region 102 may correspond to a first braking percentage contributed by a first braking source. The second region 106 may correspond to a second braking percentage contributed by a second braking source. Thus, the position of the braking indicator 98 between the first and second boundaries may indicate a current distribution of braking between the first braking source and the second braking source.Furthermore, the distance between the first limit 94 and the second limit 96, although fixed, may represent the total braking power (or total braking torque).

[0047] The first braking source may be the regenerative braking system 64, and the second braking source may be the friction braking system 62. When the vehicle speed exceeds a first speed threshold, friction braking may not contribute to the total braking until the regenerative braking amount reaches the regenerative braking threshold. However, the friction braking system 62 may be engaged to meet the total braking demand when the total braking demand exceeds the regenerative braking threshold. In this regard, the braking indicator 98 may move away from the second boundary 96 toward the first boundary 94 as friction braking is increased, in turn increasing the percentage contribution of the friction braking system 62 to the total braking amount.Furthermore, the braking indicator 98 may correspond to the regenerative braking threshold 104 when the regenerative braking threshold has been reached and the vehicle speed exceeds the first speed threshold. Accordingly, the first region 102 may correspond to a current regenerative braking value approximately equal to a regenerative braking threshold when the vehicle speed exceeds the first speed threshold.

[0048] As previously described, a mixture of regenerative braking and friction braking may occur even if the regenerative braking level has not reached the regenerative braking threshold. Even if regenerative braking is not at its current maximum, friction braking may be introduced into the braking system 58 at lower vehicle speeds. In this way, friction braking may be introduced while regenerative braking is gradually discontinued. Eventually, regenerative braking may be gradually discontinued completely before the vehicle speed reaches zero.

[0049] In accordance with one or more embodiments of the present application, friction braking may begin to be blended with regenerative braking when the vehicle speed is below the first vehicle speed threshold. Furthermore, regenerative braking may be completely removed when the vehicle speed falls below a second vehicle speed threshold that is less than the first vehicle speed threshold. The vehicle may begin to gradually discontinue regenerative braking at the first vehicle speed threshold, such that regenerative braking is gradually reduced until it can be gradually discontinued completely at the second vehicle speed threshold. Gradually discontinuing regenerative braking in this manner ensures a smoother transition from pure regenerative braking to pure friction braking.

[0050] In this regard, the braking indicator 98 may not necessarily correspond to the regenerative braking threshold. Rather, it may only provide an indication of the distribution of braking between the regenerative braking system 64 and the friction braking system 62. Accordingly, the first region 102 may correspond to a current regenerative braking value that is less than the regenerative braking threshold when the vehicle speed is less than a first speed threshold and greater than a second speed threshold. In one or more embodiments of the present application, the braking status indicator 100 may also convey that the vehicle 10 is operating in the mixed braking mode. For example, the braking status indicator 100 may display text including both "REP" and "FRICTION." Furthermore, the term "FRICTION" may be shown above the term "REP." when the second region 106 is associated with friction braking.Alternatively, the brake status indicator 100 may instead display “MIXED.” or similar text when a combination of regenerative braking and friction braking is applied.

[0051] Fig. 3(c) illustrates an exemplary embodiment of the brake indicator 90 in a pure friction braking mode in accordance with one or more embodiments of the present application. As previously described, the pure friction braking mode may occur, for example, at vehicle speeds lower than the second speed threshold. As can be seen therein, the brake indicator 90 may include the first region 102 defined by the brake indicator 98 and the first boundary 94. In the pure friction braking mode, the second boundary 96 may be a friction braking threshold 108 corresponding to a maximum friction braking value. Furthermore, the brake indicator 98 may correspond to the current friction braking value. In this regard, the brake indicator 90 may Fig. 3(c) similar to that in Fig. 2(a)-(d) when the regenerative braking value is zero. Accordingly, the braking indicator 98 may indicate the current friction braking value relative to the current maximum friction braking value. The braking indicator 98 may be positioned between the first boundary 94 and the second boundary 96 based on the current friction braking value mapped from 0%-100%, where 0% corresponds to zero friction braking (e.g., the first boundary) and 100% corresponds to the calibratable maximum friction braking value represented by the friction braking threshold (e.g., the second boundary). As previously described, the mapping of the friction braking value to the friction braking percentage for the display may be accomplished using calibratable tables that allow for nonlinear, tunable behavior.

[0052] As in Fig.3(c), the brake status indicator 100 may also indicate that the vehicle 10 is in a friction-only braking mode. The brake status indicator 100 may display, illuminate, or otherwise communicate the friction-only braking mode. For example, the brake status indicator 100 may display the text "FRICTION." The brake gauge 90 may also utilize other indicators. For example, a particular color or hue of the brake indicator 98 and / or the first region 102 may be associated with friction braking. Thus, a driver may be alerted to the friction-only braking mode if only the first region 102 is displayed in a color associated with friction braking.

[0053] Although exemplary embodiments have been described above, these embodiments are not intended to describe all possible forms of the invention. Rather, the description is to be considered descriptive rather than restrictive, and it should be understood that various changes may be made without departing from the spirit and scope of the invention. Furthermore, the features of various implementing embodiments may be combined to form further embodiments of the invention.

Claims

[1] Information display system (66) comprising: a regenerative braking indicator including a regenerative braking indicator corresponding to a current regenerative braking value and a static regenerative braking threshold (82) corresponding to a regenerative braking threshold value; and a control system configured to: Receiving at least one input relating to current operating conditions of a vehicle (10), Determining the regenerative braking threshold based on the current operating conditions, and Providing at least one output to the regenerative braking indicator to position the regenerative braking indicator relative to the regenerative braking threshold (82) based on the current regenerative braking value and the regenerative braking threshold, wherein the regenerative braking threshold is dynamic, characterized by that the regenerative braking threshold is a minimum of a powertrain braking limit and an electric battery charging system limit. [2] The information display system (66) of claim 1, further comprising: a friction brake gauge adjacent to the regenerative brake gauge, the friction brake gauge including a friction brake indicator (86) corresponding to a current friction brake value and a static friction brake threshold (84) corresponding to a maximum friction brake value. [3] The information display system (66) of claim 2, wherein the control system is further configured to provide at least one output to the friction brake gauge during a braking event to indicate the current friction brake value greater than zero when the current regenerative braking value is less than the regenerative braking threshold and the vehicle speed is below a first vehicle speed threshold. [4] The information display system (66) of claim 3, wherein the control system is further configured during the braking event to provide the at least one output to the friction braking gauge to indicate the current friction braking value greater than zero and the at least one output to the regenerative braking gauge to indicate the current regenerative braking value approximately equal to zero when the vehicle speed is below a second vehicle speed threshold, the second vehicle speed threshold being less than the first vehicle speed threshold. [5] The information display system (66) of claim 1, wherein the regenerative braking threshold is a power-based value and the powertrain braking limit is based on a powertrain braking torque limit and vehicle speed. [6] The information display system (66) of claim 5, wherein the current regenerative braking value is based on the vehicle speed and the regenerative torque. [7] The information display system (66) of claim 1, wherein the regenerative braking threshold is a torque-based value.

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