Methods for managing vehicle mileage

Abstract

The present invention relates to a method for managing the mileage of an electric tractor powered by a battery (1), the battery comprising a working capacity (2) and a reserve (3). According to the invention, when the vehicle indicates that the remaining mileage is equal to the guaranteed mileage, the method includes the step of displaying the mileage that decreases linearly over time, regardless of future driving conditions of the vehicle.

Description

[0001] This invention relates to a method for managing the mileage of a vehicle. The method according to the invention is particularly applicable to any electric traction vehicle powered by an electric traction battery.

[0002] The mileage of an electric tow vehicle is a parameter that must be well controlled, otherwise there is a risk of serious customer disappointment. Specifically, an inaccurate estimate of this mileage could cause the vehicle to stop due to insufficient power, forcing the customer to call a roadside assistance vehicle to tow it to a charging point.

[0003] The estimated remaining range of electric vehicles is usually displayed on the dashboard to inform the driver how many kilometers their vehicle is expected to travel. Drivers now tend to treat this information as absolute truth. However, such a displayed range is typically only a rough estimate of how many kilometers the vehicle can still travel, as this number depends on several inherently variable factors: past and future driving style, road type, vehicle quality, weather conditions, etc.

[0004] The amount of energy stored in a battery is typically expressed as a percentage of its storage capacity. In the following text of this document, this percentage information will be referred to as SOC (“State of Charge”). Therefore, a fully charged battery has an SOC of 100%, while an empty battery has an SOC of 0%.

[0005] Therefore, State of Charge (SOC) and stated range are the most commonly used metrics by drivers when managing their electric vehicles. The importance of SOC and range estimates increases significantly when the battery is low, as customers rely on these metrics when deciding whether to continue driving or stop to charge their vehicles. Therefore, it is crucial that customers can trust the stated range to avoid getting into trouble due to inaccurate estimates.

[0006] Application FR 3018480 discloses a method for limiting the "variability" of mileage displayed to the driver, which typically depends on highly variable driving conditions. To this end, stored energy is first divided into a "nominal" amount and a "reserve" amount. Next, actual instantaneous energy consumption is estimated. Finally, if the consumed energy is less than a predefined threshold, the vehicle's remaining mileage is calculated solely from the nominal amount; otherwise, if the consumed energy exceeds the threshold, the vehicle's remaining mileage is calculated from both the nominal and reserve amounts.

[0007] As can be seen from this application, by gradually using the energy reserve under certain conditions, the estimated and displayed mileage remains almost constant regardless of the vehicle's usage conditions. Furthermore, the driver is completely unaware of the existence of this reserve; he is never aware that the displayed mileage can optionally utilize the reserve to compensate for adverse driving conditions.

[0008] The main drawback of the method according to FR 3018480 is that, because it is implemented across the entire SOC range (100% to 0%) and the reserve is very limited, it is necessary to set the threshold for considering reserves to a very high value to avoid prematurely and excessively considering reserves when estimating remaining mileage, thus ensuring the method is effective for as long as possible. In other words, the method can overcome a limited number of high overspending peaks, but cannot exceed this number, as this could potentially make the method less effective. In particular, at the end of the SOC range (close to 0%), even under low overspending conditions, it may be less effective, which is precisely when anxiety is most likely to arise.

[0009] The method for managing the mileage of an electric vehicle according to the present invention enables the display of the remaining mileage in the vehicle at the end of the State of Charge (SOC) range, which changes visually regardless of driving conditions, and the displayed mileage can optionally take into account the battery's reserve energy capacity. Hereinafter, this reserve energy capacity will be simply referred to as "reserve".

[0010] The subject of this invention is a method for managing the mileage of a battery-powered electric tractor vehicle, the battery including working capacity and reserves.

[0011] According to the present invention, the method includes a final step of displaying the mileage that decreases linearly over time when the remaining mileage of the vehicle is equal to or less than the minimum guaranteed mileage (Km_guaranteed), regardless of the driving conditions of the vehicle.

[0012] To eliminate any ambiguity, working capacity and reserve are two distinct parts of a battery. Working capacity corresponds to the battery capacity purchased by the user, while reserve remains hidden from the user.

[0013] Therefore, the method according to the invention is applicable to vehicles having batteries that include working capacity and reserves, and is intended to assure the driver that the vehicle is actually capable of driving the last few kilometers corresponding to the displayed mileage, regardless of future driving conditions. The method according to the invention is triggered from a minimum threshold state of charge that takes into account the battery's working capacity. Once this minimum threshold state of charge is reached, the onboard computer displays the remaining mileage, which depends on the vehicle's previous driving conditions and will change visually over time, i.e., decrease linearly over time, regardless of future driving conditions. Two scenarios may then occur:

[0014] If future driving conditions are the same as or even less demanding than previous driving conditions, the linear reduction in remaining range will be ensured solely by the battery's working capacity.

[0015] If future driving conditions for the vehicle are more demanding than previous driving conditions, the linear reduction in the displayed remaining range will be ensured by the battery's working capacity and the battery's reserves.

[0016] The method according to the invention does not systematically draw upon the battery reserves to ensure a linear decrease in the remaining battery range, but rather only draws them upon when necessary. In the context of the method according to the invention, the reserves are used only in certain specific circumstances to ensure a linear decrease in the remaining electric range, thereby reassuring the driver who knows that their vehicle will be able to travel the distance given by the displayed remaining mileage.

[0017] According to one possible feature of the invention, the mileage of the vehicle before reaching the minimum guaranteed mileage is determined based on the state of charge of the battery by taking into account the battery's working capacity rather than its reserve, and taking into account the vehicle's previous driving conditions.

[0018] According to one possible feature of the invention, the final display step includes taking into account the battery's operating capacity and reserves if the current driving conditions of the vehicle are more demanding than previous driving conditions, to ensure that the displayed mileage decreases linearly. Specifically, the vehicle's electric mileage is based on the state of charge taking into account the battery's operating capacity and on the vehicle's previous driving conditions. Therefore, if the vehicle's current driving conditions are more demanding than previous driving conditions, the battery's operating capacity alone may be insufficient to ensure that the displayed remaining mileage decreases linearly, and it will be necessary to draw upon the battery's reserves.

[0019] According to one possible feature of the invention, the method receives the following values ​​as input:

[0020] -USOC_battery_not_filtered corresponds to the actual physical state of charge level of the battery, expressed as a percentage of its capacity, taking into account both the operating capacity and the reserve.

[0021] -Margin_battery_inf corresponds to the energy reserve and is equal to the difference between the battery's working capacity and its actual capacity, expressed as a percentage of its capacity.

[0022] -range_km corresponds to the mileage displayed to the customer on the dashboard, expressed in kilometers.

[0023] -distance_km corresponds to the distance the vehicle has traveled, expressed in kilometers.

[0024] -km_guaranteed corresponds to the minimum guaranteed mileage.

[0025] According to one possible feature of the invention, the method includes calculating the state of charge (USOC_filtered_range_nominal) of the restricted battery within its nominal operating range using the following formula:

[0026]

[0027] The limited battery corresponds to the battery's operating capacity or nominal capacity, and has no reserve.

[0028] According to one possible feature of the invention, once the stated mileage (Range_km) is greater than the minimum guaranteed mileage (Km_guaranteed), the method includes the previous step of displaying the state of charge of the restricted battery within its nominal operating range.

[0029] According to one possible feature of the invention, the final display step includes calculating a virtual state of charge (USOC_xxkm), starting when the stated mileage is equal to or less than the minimum guaranteed mileage (Km_guaranteed), which decreases linearly with the distance traveled.

[0030] According to one possible feature of the invention, the final display step includes displaying the final state of charge (USOC_filtered_customer) given by the following formula:

[0031] USOC_filtered_customer=Max(USOC_filtered_range_nominal, Min(USOC_xxkm, USOC_battery_not_filtered))

[0032] This formula ensures that the State of Charge (SOC) will only be guaranteed for the final few kilometers if the driver has "over-consumed" the previous consumption relative to the mileage considered when calculating the displayed distance. This allows for a guaranteed final few kilometers for the driver, enabling them to avoid unexpected breakdowns that would be difficult to manage.

[0033] The management method according to the invention allows the vehicle to reliably and dependably ensure the displayed last few kilometers when estimating the vehicle's mileage, even under more demanding driving conditions that tend to increase power consumption. The management method according to the invention has the advantage of being implementable without requiring modifications to the vehicle and battery, and without adding extra components (which are a source of cost and volume).

[0034] The following detailed description of a preferred embodiment of the management method according to the present invention is given with reference to the accompanying drawings:

[0035] [ Figure 1 [Illustration] is a schematic diagram of the battery of a vehicle to which the management method according to the present invention is applied.

[0036] [ Figure 2 This is a general flowchart illustrating the various steps of the management method according to the present invention;

[0037] [ Figure 3 [This is a flowchart illustrating the operation of the third block of the software used to drive the management method according to the present invention.]

[0038] [ Figure 4 [This is a flowchart illustrating the operation of the fourth block of the software used to drive the management method according to the present invention.]

[0039] [ Figure 5 [This is a time function graph used to compare the estimated mileage with the actual distance traveled by the vehicle when the management method according to the invention is activated, in the case of increased power consumption in the last few kilometers.]

[0040] [ Figure 6 ] is used for Figure 5 The time function graphs for comparing various SOCs in the example shown are as follows.

[0041] [ Figure 7 [This is a time function graph used to compare the estimated mileage with the actual distance traveled by the vehicle when the management method according to the invention is activated, assuming reduced power consumption in the last few kilometers.]

[0042] [ Figure 8 [This shows the method for...] Figure 7 The time function graphs for comparing various SOCs in the example shown are illustrated.

[0043] The term SOC stands for State of Charge.

[0044] refer to Figure 1 The method for managing vehicle mileage according to the present invention is applicable to electric traction vehicles powered by a battery 1, which includes a working capacity 2 and a reserve 3, wherein the reserve 3 preferably represents 5% to 30% of the actual total capacity (working capacity + reserve) of the battery 1. This method can be applied to any situation where the battery's nominal operating range is reduced relative to its actual capacity. This limitation results in an available energy margin (reserve) lower than the customer's nominal operating range, thus resulting in a SOC of 0%.

[0045] There are many examples on the market of electric vehicles that incorporate batteries with a physical capacity greater than the nominal capacity. Specifically, in the case of multi-battery (small / large capacity) products, it may be more economical for vehicle manufacturers to produce only a single physical unit to avoid an excessive number of parts while still providing different ranges. The method according to the invention allows for the intelligent utilization of this additional energy margin (reserve) to provide additional benefits in the vehicle without requiring additional investment from the manufacturer.

[0046] The management method according to the invention includes the step of displaying mileage that decreases linearly over time when the vehicle indicates that the remaining mileage is equal to a very low predetermined threshold, regardless of future driving conditions of the vehicle.

[0047] In other words, the vehicle's mileage prediction is based solely on the working capacity 2 of battery 1, or more precisely, on the state of charge (SOC) considering said SOC and the vehicle's driving history over the distances already traveled. The reserves 3 of battery 1 are not involved in this mileage prediction. Therefore, when the displayed mileage indicates to the driver that the vehicle can only travel a few more kilometers, it is important for the driver to be certain that the vehicle will be able to travel those kilometers regardless of future driving conditions, without the unfortunate situation of the vehicle being stranded on the side of the road due to insufficient power. This method is triggered when the SOC of battery 1's working capacity 2 reaches a minimum threshold. Once this threshold is reached, the onboard computer calculates the remaining mileage based on the vehicle's previous driving conditions and then displays the remaining mileage in a way that is intuitive for the driver (i.e., linearly decreasing over time). Two scenarios may then occur:

[0048] If the vehicle's future driving conditions are the same as or less demanding than the previous driving conditions, the linear reduction in the displayed remaining range will be ensured solely by the working capacity 2 of battery 1.

[0049] If future driving conditions for the vehicle are more demanding than previous driving conditions, the linear reduction in the displayed remaining range will be ensured by the battery's working capacity and the battery's reserves.

[0050] Driving conditions that may increase power consumption can be selected from increased vehicle speed, increased engine speed, inclined road surfaces, weather conditions, and aggressive driving style. The conditions listed above can be considered individually or in combination. They are illustrative and non-limiting examples of adverse conditions that may increase vehicle power consumption.

[0051] refer to Figure 2 The management method according to the present invention is driven by software, which includes input 10, first block 11, second block 12, third block 13 and fourth block 14.

[0052] Enter 10 as shown below:

[0053] -USOC_battery_not_filtered[%]: This signal indicates the actual physical state of charge level of the battery, expressed as a percentage of its capacity.

[0054] -Margin_battery_inf[%]: Energy margin, corresponding to the difference between the battery's working capacity and its actual capacity.

[0055] -Range_km[km]: The mileage displayed to the customer on the dashboard.

[0056] -Distance_km[km]: The distance the vehicle has traveled.

[0057] -Km_guaranteed: This parameter allows you to select the number of kilometers you want to guarantee using this strategy.

[0058] The parameter for setting this strategy is Km_guaranteed[km]. This parameter allows you to select the number of kilometers you want to guarantee using this strategy.

[0059] The first calculation is limited to the SOC of battery 1 within its nominal operating range. This signal is displayed to the customer whenever the stated range_km is greater than the "guaranteed" km number Km_guaranteed; this signal will be referred to as "USOC_filtered_range_nominal".

[0060] The signal USOC_filtered_range_nominal is obtained using the following equation:

[0061]

[0062] The second block 12 produces a Boolean value that compares the stated mileage with the final few kilometers guaranteed by the strategy.

[0063] The output of this block is a Boolean value given by the following formula:

[0064]

[0065] refer to Figure 3 The third block (13) defines a new virtual SOC signal, called USOC_xxkm. Starting when the represented mileage falls below a threshold km_guaranteed, this signal decreases linearly with the distance traveled, corresponding to the guaranteed mileage. Therefore, when the car has actually traveled the last few km km_guaranteed, the output signal USOC_xxkm reaches its value of 0%.

[0066] The logic used to generate the third block 13 is as follows: Figure 3 As shown, it's important to review the following:

[0067] -Distance_km[km]: The actual distance traveled by the vehicle.

[0068] -Km_guaranteed[km]: This parameter sets the guarantee distance for the policy (e.g., you could choose a value of 5km for this parameter).

[0069] -USOC_filtered_range_nominal: SOC of battery 1 calculated within the nominal range 2 of the restricted battery (output of the first block 11).

[0070] When the estimated range is below km_guaranteed(km), block 13 calculates the SOC that decreases linearly with the distance traveled, such that the calculated value reaches 0 at the end of km_guaranteed(km). When the range is greater than km_guaranteed(km), the output of block 13 is the SOC USOC_filtered_range_nominal of the restricted battery's nominal range 2 calculated by the first block 11.

[0071] refer to Figure 4 The fourth block, 14, calculates the final SOC that will be displayed to the customer on the car's dashboard. The purpose of this block 14 is to modify the SOC calculated by the first block, 11, within the limited nominal range only when necessary. That is, when the SOC reaches 0% before the driver is able to drive the last few kilometers (km_guaranteed) already presented to them. To this end, when the mileage falls below the km_guaranteed km threshold, the nominal range SOC (USOC_filtered_range_nominal) is continuously compared with the virtual SOC (USOC_xxkm) constructed by the third block, 13, within the last few kilometers, to present the customer with the maximum value between these two values, saturated with the actual SOC of battery 1, ensuring it never deviates from the battery's physical range. Therefore, the final SOC displayed to the customer is:

[0072] -SOC_filtered_customer=Max(USOC_filtered_range_nominal, Min(USOC_xxkm, USOC_battery_not_filtered))

[0073] This formula ensures that the State of Charge (SOC) will only be guaranteed for the final few kilometers if the driver has "over-consumed" the previous consumption relative to the mileage considered when calculating the displayed distance. Therefore, this guarantees the stated final few kilometers even with significant changes in driving style or consumption, thus preventing untimely and unexpected breakdowns that would lead to customer dissatisfaction.

[0074] Specifically, if the driver reduces their energy consumption in the last few kilometers of the guaranteed range, particularly through the regeneration phase (which allows the battery to be charged and allows the restricted SOC (USOC_filtered_range_nominal) to return above the calculated value), the strategy will display USOC_filtered_range_nominal, thus allowing the customer to use the recovered energy to travel beyond, for example, the guaranteed 5km. Therefore, this strategy ensures that deviations from the nominal operating range of restricted battery 1 are only permitted if it is advantageous to the customer.

[0075] Once the SOC USOC_filtered_customer has been calculated according to the above strategy:

[0076] - Engine torque is naturally managed to gradually decrease as USOC_filtered_customer approaches zero, so that battery "starvation" never occurs before USOC_filtered_customer reaches zero. In fact, it is this torque management, consistent with USOC_filtered_customer calculations, that ensures the ability to drive for the last few kilometers.

[0077] - The mileage presented to the customer in the last few km_guaranteed is logically consistent with the last few km_guaranteed.

[0078] To verify the management method according to the present invention, two driving examples are given: driving with high energy consumption and no regeneration phase in the last few kilometers, and driving with a significant regeneration phase.

[0079] Figure 5 and Figure 6 The examples show driving scenarios where energy consumption increases in the last few kilometers. It's important to note in both graphs that once the mileage drops below the guaranteed 5km (km_guaranteed = 5 in this example), the strategy is activated, and the SOC shown to the customer decreases and only reaches 0% after driving 5km.

[0080] Figure 7 and Figure 8The diagram illustrates a driving example during the final few kilometers of reduced energy expenditure (significant recovery phase). It's important to note in both graphs that once the displayed mileage falls below the guaranteed 5km, the strategy is activated, and the State of Charge (SOC) displayed to the customer takes into account the regeneration phase and therefore the additional energy. Thus, through torque management consistent with the newly calculated SOC, this allows driving beyond 5km, enabling the driver to utilize the recovered energy.

[0081] These examples demonstrate that this strategy allows for guaranteed driving in the last few kilometers while taking into account potentially favorable variations in vehicle consumption with respect to mileage. It should be noted that this strategy works under all driving conditions, thus achieving the same performance in the last few kilometers regardless of whether the weather is hot or cold, whether the battery is aging, whether the vehicle is charging, whether it is on mountain roads, and for any type of driving.

[0082] It should be noted that the management method according to the invention becomes more advantageous when the reserve is larger. Specifically, the larger the reserve, the greater the mileage that can be guaranteed. There are many examples on the market of electric vehicles that include batteries with additional energy capacity hidden from the user, because in the case of multi-battery (small / large capacity) products, it may be more economical for manufacturers to produce only a single physical object to avoid an excessive number of parts, while still providing different mileage (and, of course, different purchase prices for different customers). The present invention makes it possible to provide additional benefits by intelligently utilizing this additional energy margin without requiring additional investment from the manufacturer.

Claims

1. A method for managing the mileage of an electric tractor powered by a battery (1), the battery comprising a working capacity (2) and a reserve (3), characterized in that, The method includes a final display step whereby, when the vehicle's remaining mileage is equal to or less than the minimum guaranteed mileage Km_guaranteed, the displayed mileage decreases linearly over time, regardless of the vehicle's driving conditions. This final display step further includes considering the available capacity and reserve if the vehicle's current driving conditions are more demanding than previous driving conditions, to ensure that the displayed mileage decreases linearly. The method receives the following values ​​as input (10): -USOC_battery_not_filtered corresponds to the actual physical state of charge level of the battery, expressed as a percentage of its capacity, taking into account both the operating capacity and the reserve. -Margin_battery_inf corresponds to the energy reserve and is equal to the difference between the battery's working capacity and its actual capacity, expressed as a percentage of its capacity. -range_km corresponds to the mileage displayed to the customer on the dashboard, expressed in kilometers. -distance_km corresponds to the distance the vehicle has traveled, expressed in kilometers. -km_guaranteed corresponds to the minimum guaranteed mileage.

2. The method as described in claim 1, characterized in that, The mileage of the vehicle before reaching the minimum guaranteed mileage is determined based on the state of charge of the battery by taking into account the working capacity (2) of the battery (1) rather than the reserve (3) and the previous driving conditions of the vehicle.

3. The method as described in claim 1, characterized in that, This method includes calculating the state of charge (USOC_filtered_range_nominal) within the nominal operating range of the confined battery using the following formula:

4. The method as described in claim 3, characterized in that, Once the stated range_km is greater than the minimum guaranteed mileage Km_guaranteed, the method includes the previous step of displaying the state of charge of the restricted battery within its nominal operating range.

5. The method according to any one of claims 1 to 4, characterized in that, The final display step includes calculating the virtual state of charge USOC_xxkm, which begins when the stated mileage is equal to or less than the minimum guaranteed mileage Km_guaranteed, and decreases linearly with the distance traveled.

6. The method as described in claim 5, characterized in that, This final display step includes displaying the final state of charge, USOC_filtered_customer, given by the following formula: USOC_filtered_customer=Max(USOC_filtered_range_nominal,Min(USOC_xxkm,USOC_battery_not_filtered)).

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