Method and device for operating an electrically powered motor vehicle

Abstract

Method for operating an electrically powered motor vehicle with a battery-powered electric drive motor and a generator-coupled internal combustion engine for providing electrical energy to the electric drive motor and / or the battery, wherein the internal combustion engine is operated based on the state of charge of the battery (REX operating mode), wherein a route to a previously entered destination is determined by means of a navigation device (12), and, based on the determined route, a recorded battery state of charge (16) and a recorded energy consumption, it is checked (14), in particular cyclically, whether the destination is reached or whether there is a range gap (dRW) to the destination, and a corresponding recommendation for action (22) to activate the REX operating mode (26) is issued to the driver, characterized in that, if a range gap (dRW) is detected, it is determined (22)whether the destination is reached in at least one specified energy-saving operating mode (32, 34) in which energy consumption is reduced, and whether, in the case of a route passing through at least one environmental zone, an alternative route bypassing the at least one environmental zone is suggested by the navigation system if this allows a range gap to be closed due to the possibility of continuous REX operation.

Description

[0001] The invention relates to a method for operating an electrically powered motor vehicle with a battery-powered electric drive motor and a generator-coupled internal combustion engine for providing electrical energy to the electric drive motor and / or the battery, wherein the internal combustion engine is operated based on the battery's state of charge (REX operating mode). The invention further relates to a device for carrying out such a method according to the preamble of claim 1.

[0002] Such a procedure is known from FR 2 923 187 A1. Environmental zones are also taken into account when determining the route.

[0003] The range of battery-powered electric vehicles is a common source of concern. Unlike fuel-powered vehicles, where refueling allows for virtually unlimited range extension with minimal time investment and widespread availability, the high-voltage battery of an electric vehicle can only be charged at a limited number of locations, and the charging process takes considerably longer than refueling a combustion engine vehicle. This concern is exacerbated when the battery is not fully charged at the start of a journey or when longer distances need to be covered.

[0004] DE 103 02 504 A1 discloses a method for determining a route for a purely electric vehicle that includes several energy-saving operating modes to increase the range. Therefore, environmental zones located along the route do not play a role in determining the route.

[0005] DE 10 2006 062 584 A1 discloses a method for operating an electric vehicle, for example an electric bicycle, with recuperative charging of the battery during driving.

[0006] Another method is known from DE 10 2008 059 199 A1. This describes an electric vehicle with a so-called range extender, which is exclusively electrically powered, and furthermore provides a low-power combustion engine with a coupled generator for recharging the battery.

[0007] Methods for operating hybrid vehicles consisting of electric and combustion engines are known from JP H08 - 126 116 A or JP 2000 - 188 802 A, in which battery charging is controlled based on navigation data.

[0008] It is known that special energy-saving operating modes can be provided for hybrid and electric vehicles, in which energy consumption is reduced to increase the vehicle's range. For example, it is possible to limit or completely disable the operation of large energy consumers such as air conditioning or heating systems to save energy. Furthermore, a maximum speed limit or a power limit for the drive electric motor can be activated. These energy-saving operating modes are currently selected manually by the driver.

[0009] The object of the invention is to provide a generic method for determining a route to a destination for a hybrid vehicle, i.e. with a battery-powered electric drive motor and a generator-coupled combustion engine for providing electrical energy for the electric drive motor or the battery, which takes into account the presence of environmental zones on the way to the destination.

[0010] The invention is defined by the features of the independent claims. Advantageous further developments and embodiments are the subject of the dependent claims. Further features, applications, and advantages of the invention will become apparent from the following description and the explanation of exemplary embodiments of the invention illustrated in the figures.

[0011] The method according to the invention ensures that a driver is not surprised to find that the entered destination cannot be reached. Rather, the driver can depart after entering the destination, unless the system determines at the start of the journey that the destination is unattainable even with full REX operation. Thus, if the method according to the invention ensures that the destination is reached, the driver can depart with peace of mind. If, during the particularly cyclical execution of the method according to the invention, it is determined at a later point in time that the destination is no longer attainable without limiting the electrical consumers – perhaps due to the interim activation of large energy consumers such as air conditioning or due to fast or sporty driving – and switching to an energy-saving operating mode is recommended, the driver can follow this recommendation or not.If the driver follows the recommendation, the selected energy-saving mode is activated and the destination is reached. However, if the driver does not follow the recommendation, for example, by selecting a less powerful energy-saving mode than recommended, this is implemented, even if it does not initially close the range gap and the destination would not be reached. The same preferably occurs if the driver does not react to the recommendation at all, i.e., lets everything continue as normal. Only if, using the method according to the invention, it is later determined that the destination cannot be reached without REX mode, does the system automatically switch to REX mode, in which a portion of the energy consumed by the electric motor is supplied by the combustion engine, thus extending the range accordingly.When determining the range gap (dRW) during REX operation, the system checks whether the recommended route leads through a low-emission zone where REX operation is prohibited and takes this into account when calculating the potential range gap (dRW). Therefore, the driver does not need to worry about low-emission zones when choosing a route, or the navigation system can determine the route accordingly, taking into account that REX operation is prohibited in certain areas. It is also possible to have the navigation system suggest an alternative route that bypasses low-emission zones for routes that do pass through them, and to check whether this increases the range due to the possibility of continuous REX operation, or whether it closes a range gap.

[0012] According to an advantageous embodiment of the invention, a maximum speed limit is implemented in the at least one energy-saving operating mode. This reduces the specific energy consumption per distance due to the reduced air resistance and thus increases the vehicle's overall driving range. Alternatively, a power limit can be implemented, which has the advantage of allowing higher speeds to be achieved when driving with a tailwind or downhill.

[0013] According to a further advantageous embodiment of the invention, the energy consumption of an air conditioner and / or an electric heater is limited in the at least one energy-saving operating mode.

[0014] According to a further advantageous embodiment of the invention, two or more energy-saving operating modes with graduated energy-saving settings are provided. Preferably, in a first energy-saving operating mode with lower energy savings, the energy consumption of large consumers such as an air conditioner is limited, and in a second energy-saving operating mode, it is completely prevented. It is also conceivable to allow the driver to gradually adjust the degree of energy restriction.

[0015] According to a further advantageous embodiment of the invention, the energy-saving mode is also activated when the REX operating mode is activated. This makes it possible to increase the range even further.

[0016] According to an advantageous embodiment of the invention, a device for carrying out the above-described methods is proposed, comprising a range management unit to which the following data can be supplied: - Route data from the navigation device - Battery charge status data - Electricity consumption data on the operating status of electricity consumers - Operating status data of the drive electric motor and has the following signal outputs: - a signal indicating a recommendation for action - Control signals for controlling the operating mode of electrical consumers - Control signals for controlling the drive electric motor to limit the maximum speed and / or power.

[0017] Such a range manager makes it possible to carry out the method according to the invention and to perform the necessary interactions with the driver.

[0018] According to an advantageous embodiment of the invention, the range management unit comprises a display and input unit by means of which the range situation can be displayed to the driver and, in particular, in the event of a range gap, a suggestion to activate an energy-saving operating mode is displayed.

[0019] Further advantages, features, and details will become apparent from the following description, in which an exemplary embodiment is described in detail with reference to the drawing. The features described and / or illustrated, either individually or in any meaningful combination, constitute the subject matter of the invention, optionally also independently of the claims, and may, in particular, also be the subject of one or more separate applications. Identical, similar, and / or functionally equivalent parts are designated with the same reference numerals.

[0020] The figure shows a block diagram of the method according to the invention. First, in an input step 10, the driver enters the destination before starting the journey, from which the route is determined in the route calculation step 12, taking into account position data from a navigation system.

[0021] In range prediction step 14, the calculated route, possibly taking into account altitude information or other information such as speed limits, as well as the battery state of charge (SOC) determined in battery state determination step 16, stored energy consumption data, and current energy consumption, are used to calculate whether the destination can be reached without energy consumption restrictions or whether there is a range gap. If the route passes through a low-emission zone where the operation of combustion engines, and therefore REX operation, is prohibited, a necessary battery charge reserve (SOC reserve) is taken into account.

[0022] The data collected is preferably displayed visually to the driver in a signaling step 18, along with information about environmental zones and / or other information such as the battery charge level still available at the destination.

[0023] If no range gap is detected in range gap determination step 20 (meaning the vehicle is expected to reach the destination), the system returns to route calculation step 12 and repeats the range prediction in step 14, taking current position and battery status data into account. However, if a range gap is detected in range gap determination step 20 (meaning the destination will not be reached), range extension determination step 22 determines whether the destination can be reached by activating one or more energy-saving modes or whether the REX mode must be activated. This involves performing calculations for all stored energy-saving modes and the REX mode, taking into account stored energy consumption data for various energy consumers and current measured energy consumption data.The calculations in range increase determination step 22 largely correspond to the calculations carried out in range prediction step 14, except that different energy consumption restrictions are used as a basis.

[0024] Step 24 checks whether the REX operating mode was selected in the range extension determination step 22. This would mean that even with the activation of the energy-saving operating mode, which imposes the most significant energy consumption restrictions, the destination cannot be reached, and the REX operating mode must therefore be activated. In this case, REX operating mode 26 is automatically activated. This switches on the existing (not shown) low-power combustion engine, which drives a generator and thus provides some of the energy required by the (not shown) electric drive motor or recharges the battery. The activation of REX operating mode is also indicated to the driver visually and / or audibly.

[0025] If, however, according to step 24 only one of the energy-saving operating modes, but not the REX operating mode, has been determined to be sufficient to reach the destination, the driver will then be shown the corresponding recommendation for action (e.g. to activate a first or second energy-saving operating mode) visually and preferably also audibly in the operating mode recommendation step 28.

[0026] In operating mode selection step 30, the driver can select one of the energy-saving operating modes 32 or 34 based on the recommendation. This instruction is then implemented, and the system switches to either a first energy-saving operating mode 32 or a second energy-saving operating mode 34 according to its instructions. If the recommendation was to select the more energy-efficient second energy-saving operating mode 34, but the driver, contrary to the recommendation, selects the less energy-efficient first energy-saving operating mode 32, which cannot completely close the range gap (e.g., because the air conditioning should not be completely switched off due to high outside temperatures), then this selected operating mode will still be activated initially.

[0027] However, if the driver makes no decision at all in the operating mode selection step 30, nothing happens, but the system returns to step 12 and the range gap calculation is repeated cyclically using updated position and battery status data.

[0028] During subsequent loop iterations, the way a range gap is signaled can be changed, e.g. visually through different colors or different or differently loud sounds.

[0029] If the first energy-saving operating mode has been selected, it will be implemented in energy-saving operating mode activation step 32, i.e., corresponding restrictions on maximum speed, maximum power, air conditioning use, etc., will be applied. The same applies if the second energy-saving operating mode has been selected; in energy-saving operating mode activation step 34, the corresponding, more drastic energy-saving measures will be implemented.

[0030] Within the scope of the invention, it is also possible to allow the driver to activate the REX operating mode independently of its necessity, for example, to create reserves for later journeys after reaching the destination. In particular, if the driver is signaled that at least one energy-saving operating mode needs to be activated, an advantageous embodiment of the invention also allows the driver to activate the REX operating mode.

Claims

[1] Method for operating an electrically powered motor vehicle with a battery-powered electric drive motor and a generator-coupled internal combustion engine for providing electrical energy to the electric drive motor and / or the battery, wherein the internal combustion engine is operated based on the state of charge of the battery (REX operating mode), wherein a route to a destination, in particular a previously entered one, is determined by means of a navigation device (12), and, based on the determined route, a recorded battery state of charge (16) and a recorded energy consumption, it is checked (14), in particular cyclically, whether the destination is reached or whether there is a range gap (dRW) to the destination, and a corresponding recommendation for action (22) to activate the REX operating mode (26) is issued to the driver. characterized by, that when a range gap (dRW) is detected, it is determined (22) whether the destination can be reached using at least one specified energy-saving operating mode (32, 34) in which energy consumption is reduced, and if the route passes through at least one environmental zone, an alternative route bypassing the at least one environmental zone is suggested by the navigation system if this allows a range gap to be closed due to the possibility of continuous REX operation. [2] Method according to claim 1, wherein if no decision is made by the driver, the REX operating mode (26) is activated when it is determined that this will be necessary to bridge the range gap (dRW). [3] Method according to one of claims 1-2, characterized by , that in at least one energy-saving operating mode (32, 34) a maximum speed limit is implemented. [4] Method according to any one of claims 1-3, characterized by , that in at least one energy-saving operating mode (32, 34) a driving performance limitation is implemented. [5] Method according to any one of claims 1 to 4, characterized by , that in at least one energy-saving operating mode (32, 34) electricity consumers, in particular air conditioning and / or electric heating devices, are operated in a restricted manner or switched off. [6] Method according to any one of claims 1 to 5, characterized by that this includes two or more energy-saving operating modes (32, 34) with graduated energy-saving settings. [7] Method according to any of the preceding claims, characterized by , that when the REX operating mode (26) is activated, an additional energy-saving operating mode (32, 34) is activated. [8] Apparatus for carrying out the method according to any of the preceding claims, characterized by that this includes a range management unit to which the following data can be fed - Route data from the navigation device - Battery charge status data - Electricity consumption data on the operating status of electricity consumers - Operating status data of the drive electric motor and the following signal outputs: - a signal indicating a recommendation for action - Control signals for controlling the operating mode of electrical consumers - Control signals for controlling the drive electric motor to limit the maximum speed and / or power. [9] Device according to claim 8, characterized by that it includes a display and input unit.

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