DE102008040308A1 - Method for detecting the state of charge of a vehicle battery and electronic control - Google Patents

Abstract

Method of an electronic control system (1) in a motor vehicle, in particular with a hybrid drive, with at least one electrical energy store (7) comprising in particular a high-voltage energy store and / or a low-energy energy store and an on-board network management system (BMS), with electrical consumers who at least one electric machine as a prime mover and as a generator, wherein the current state of charge of the energy store (7) is polled continuously and is classified within a minimum and maximum state of charge, the queried information about the state of charge on a display device (12) for the driver output become. In order to increase vehicle comfort and a driving style with a vehicle fuel resources and the current state of charge of an electrical energy storage device (7) is adaptable, a required amount of residual energy until reaching at least one allowable setpoint extreme value of the state of charge of the energy storage (7) is calculated as Information transmitted to at least one vehicle device.

Description

The The invention relates to a method of electronic control in a motor vehicle, in particular with a hybrid drive, with at least an electrical energy storage, in particular a high-voltage energy storage and / or a low-voltage energy storage and an on-board network management system (BMS) includes, with electrical consumers, at least one includes electric machine as a prime mover and as a generator, wherein the current state of charge of the energy storage queried continuously is classified and within a minimum and maximum state of charge is, with the requested information about the state of charge be issued in a display device for the driver.

The The invention further relates to a computer program product which in a program memory of a controller with program instructions loadable is.

The The invention also relates to an electronic control system for a motor vehicle, in particular with a hybrid drive drive, with a program memory and an electronic calculator, the Information about the state of charge of an energy storage interrogated in the motor vehicle and at least one vehicle device submitted for issue or further processing.

It Hybrid vehicles are known, so-called full hybrid vehicles, the have two different drive sources, z. B. an internal combustion engine and an electric machine. Such hybrid vehicles can depending on the driver's desired torque and operating strategy either purely over the internal combustion engine, purely via the electric machine or be moved using a combination of both drive sources.

additional An essential feature of hybrid vehicles is that the energy storage Charged while braking by a generator can be. This additional possibility of energy production In hybrid vehicles, in addition to the known that both in Stand as well as when driving the energy storage on the Internal combustion engine can be charged by a generator.

The Charging the energy storage is of different control variables dependent. For example, the current state of charge, in the English jargon, State of charge (SoC) and incoming Moment on the generator of the electric machine, for example by braking or by the drive of the internal combustion engine is generated, depending.

For example, in the DE 600 24 924 T2 a display in a vehicle with hybrid drive described that indicates both the state of charge of the battery and the filling state of a tank.

in principle a vehicle has a fuel gauge for the tank filling condition, which is important for operation of the internal combustion engine, to estimate how far or how long the vehicle will be can be driven without new tank filling. Based on Fuel gauge allows the driver to decide when to refill the tank must become. In addition, the driver can through the Fuel gauge to develop a driving strategy to maximize fuel economy To drive vehicle. Such a driving behavior, can also from a electronic residual mileage display, as in some modernizing Vehicles partly installed, are supported.

The DE 100 29 886 C1 describes an energy management system for a motor vehicle with respect to electrical consumers and at least one electrical energy source in the form of a fuel cell system to achieve a desired destination.

The DE 43 39 568 A1 describes a method for determining the state of charge of a vehicle starter battery, according to which a charge balance is performed by evaluating the charging and discharging. The charge balance is checked and corrected with the aid of the measured battery hoist voltage. Depending on the temperature, a time interval is determined as to how long the battery can deliver an acceptable discharge current under the specified conditions. The time interval serves as a measure of the present state of charge of the battery.

It Object of the invention, a method, a computer program product and develop a control of the type mentioned, so that a Driving with a vehicle fuel resources and gentle to the current state of charge of an electrical energy store is customizable and to increase vehicle comfort.

According to the invention the object by the subject-matter of claims 1, 9 and 10 solved. Advantageous developments emerge the dependent claims.

An idea of the invention is to calculate a required amount of residual energy and the corresponding duration up to a permissible charge state of a target extreme value of the battery as a function of control variables, such as the current state of charge of the battery, the discharge current of consumers and the incoming torque from the generator. This information will be for an adaptive driving strategy of either a parent hybrid controller or adaptive driving style provided to the driver.

The Task is solved by a required Remaining energy level until at least one permissible Target extreme value of the state of charge of the energy storage is calculated and determined as information from at least one display device becomes. An energy store usually has two desired extreme values. For example, a maximum state of charge for a battery is approximately 70% of the maximum energy is and a minimum allowable State of charge, which is for example about 30%, this minimum state of charge having a safety buffer, in which the vehicle can still be safely operated by, for example the internal combustion engine of a starter, with sufficient electricity supplied, can be started. The starter may vary depending on topology the hybrid structure will be an electric machine at the same time takes over the function of the generator or for each function have separate electrical machines.

By the information of the required amount of residual energy, the Operating strategy of the hybrid vehicle to be influenced and the Driving style to be adapted directly by the driver. In a hybrid vehicle, for example, with electric machines as electromotive Drives (electric motor) to support the internal combustion engines is formed, the electric motors can accelerate improve, so for example, overtaking faster executable. Because of the information about the remaining amount of energy, a driver can estimate whether an overtaking with Support of electrical machines as drive possible or during the overtaking process, for example possibly suddenly fails, because the residual energy of the energy storage is insufficient. As energy storage is a Battery but also any other known electrical energy storage, for example High performance capacitors, etc. understood.

Around the required residual energy with a high quality to calculate is provided according to the invention, the amount of residual energy as an exponential approximation in dependence of controlled variables, in particular the current state of charge the energy storage and an incoming moment on the generator or a charging current of a generator and a low-voltage on-board electrical system hanging loads, which have a DC / DC converter from a high-voltage on-board network of high-voltage energy storage with energy be supplied, to charge. The amount of incoming electricity is measured per unit time and depending on the adjacent Calculated voltage. The sizes of the current state of charge of the energy store, which is a battery, are conventional in one provided on-board network management system (BMS), which sizes can thus be queried and processed for further calculation. The amount of residual energy therefore changes because the nominal state of charge depending on the current state of charge more or less energy needed per unit of time to change the state of charge.

moreover is in the hybrid vehicle a special feature that, for example despite constant driving and constant road conditions for example, same gear, same accelerator pedal position and straight, horizontal road, the operating strategy varies according to can change internal control variables, so that also the amount of energy input changes. An operating strategy that of the vehicle manufacturer, for example, in a parent Hybrid control is set and deposited regulates the distribution the driver's desire torque on the different drive components, Internal combustion engine and at least one electric machine.

at an acceleration request in the plane, this is done by the Division of the electrical machine and the internal combustion engine, where either only the electric machine, the internal combustion engine or both drive components can be used. At a delay request of the driver becomes the moment on the braking system and the electric machine acting as a generator works, distributes.

Around To avoid strong fluctuations in the calculation, the amount of residual energy preferably calculated from "moving averages". The "moving averages" are parameters that are averaged from a time series.

According to one preferred embodiment, the amount of residual energy is up calculated to reach a maximum state of charge energy storage. An advantage of this information is that possible for the driver Adaptation of his driving behavior. For example, the driver knows that he only overtakes at a certain point on a certain route can, so he can estimate whether his energy storage up to this point the maximum charge state will have reached.

According to a further preferred embodiment, the residual energy amount is calculated until a minimum state of charge of the energy store is reached. This minimum state of charge is a state in which operation of the vehicle with the electric components is still possible, so that an internal combustion engine is still sufficiently started, for example can.

advantageously, will the required residual energy until reaching at least an extreme value, the state of charge of the energy storage as the remaining time and / or remaining kilometers calculated and in particular the driver the display device displayed and particularly preferably to a Hybrid control transmitted as a vehicle device in the form of information.

The needed remaining time until reaching a defined Maximum of the energy charge in the energy storage is not calculated "linearly". This is due to the fact that the voltage drop across changed the increasing charge. Therefore, the time left on a forecast of operational strategic parameters in the next Seconds are calculated. This results in an exponential Approach. The according to the invention Method derived parameters of residual time and derived accordingly Remaining kilometers can be the operating strategy of a hybrid vehicle to reduce emissions due to fuel savings. In addition, a driver can adjust his driving style, if He is the current state of charge of his electrical energy storage and beyond the remaining kilometer or remaining time knows to for example, the battery to a maximum / minimum charged Condition or discharge it to the maximum.

The Remaining energy amount is thus until reaching at least one extreme value the state of charge of the energy storage of a drive control, in particular a hybrid controller, as information for adaptation to an operating strategy transmitted.

Around the remaining time to a minimum discharge state of a battery over longer periods, d. H. several days or weeks and months to calculate are preferably the calculated information with date and time, defined according to an operating strategy of the vehicle, stored and in particular to a defined Time read out according to the operating strategy. The Information about the remaining kilometers and the remaining time up to The extreme values may be due to the additional Information of date and time also inside the vehicle at one Display device can be provided.

The Task is also solved by a computer program product, that in a program memory of a controller with program instructions is loadable to all steps of a procedure described above if the program is in control of a program Motor vehicle is running. A computer program product does not require additional components in the vehicle, but can be used as a module often in already existing controls implement in the vehicle, here for example in a hybrid control or an on-board network management system or another controller.

One Computer program product has the further advantage of being light to specific customer requirements or to individual Operating strategies is customizable.

The Task is also performed by an electronic control system for a motor vehicle with a hybrid drive solved. The electronic Control has a program memory and an electronic calculator on, the information about the state of charge of the energy storage, in particular a battery, interrogated in the motor vehicle and at least one Transmitted vehicle device for output or further processing, the controller being the method described above, in particular by means of the above-described computer program product. The electronic control can either be as a separate controller be formed in the motor vehicle, or as a module in the electrical system management system or in the hybrid controller or other controller, such as in the engine control, be integrated. The controller has an interface, which can be connected to a display device as Instrument cluster various information, in particular information from the method according to the invention, the driver can provide.

It It is understood that the above and below to be explained features not only in the specified Combination, but also usable in other combinations.

The Invention will be described below with reference to an embodiment explained in more detail with reference to drawings. Show it:

1 a schematic circuit diagram of drive components of a hybrid vehicle with an integrated controller according to the invention,

2 a flow chart of a method according to the invention,

3 a state of charge-time diagram of a battery.

The 1 shows a schematic circuit diagram of drive components of a hybrid vehicle. These drive components are all important to the inventive method of an electronic control according to the invention 1 with an implemented computer program product perform. The electronic control 1 is designed either as a separate controller or in a vehicle electrical system management system, as in 1 shown in a hybrid control 2 integrated as a module. The hybrid controller 2 is provided as a higher-level control to use a certain operating strategy with certain drive components depending on the ambient condition resulting from requested torques of the driver's desired torque and the actually available torques of an internal combustion engine and at least one electric machine.

An internal combustion engine 3 transmits torque to a gearbox 5 that too from an electric machine 4 via a clutch 8th is drivable. The torque from the transmission 5 gets on the drive wheels 13 transferred to move the vehicle. The internal combustion engine 3 is from the electric machine 4 in function of a starter by closing a clutch 6 started. The electric machine 4 is as a so-called integrated starter generator in the drive train between internal combustion engine 3 and gear 5 arranged, but can also move as a prime mover the vehicle independently - in the example clutch 6 and clutch 8th is closed. The starting electric machine transfers torque to the gearbox.

For reasons of simplicity, the hybrid control comprises 2 in the presentation of the 1 both the control of the internal combustion engine 3 as well as the control of the electric machine 4 as well as the clutch 6 , This simplification is only for the representation of 1 have been made, in fact, separate controls are often provided here. The electric machine 4 , which is used both as a starter and prime mover, as well as generator, is to a high-voltage energy storage 7 connected, which is discharged and charged by the electric machine. The high-voltage energy storage 7 For example, a Hochvoltkonden capacitor in particular of the type of a double-layer capacitor and / or a high-voltage battery, as it is already known from the prior art. To electrical consumers 14 To supply with a low voltage in the range of 12 to 14 volts with electrical energy, a low-voltage electrical system is provided that of a low-voltage energy storage, a low-voltage battery 15 is created with a voltage between 12 and 14 volts. The high-voltage energy storage 7 and the low-voltage on-board electrical system with the low-voltage battery 15 as well as the electrical consumers 14 are with a wiring system management system 9 connected. The vehicle electrical system management system includes a DC / DC converter (DC / DC converter) 16 to transfer electrical energy from the high voltage electrical system high voltage over, for example, 14 volts to a lower voltage, for example, between 12 volts and 14 volts for the low-voltage vehicle electrical system.

The wiring system management system 9 includes a regulator that controls the discharge and charge of the high-voltage energy storage 7 and from the low-voltage battery 15 monitors and controls. The wiring system management system 9 protects the highvoltage energy storage 7 and the low-voltage battery 15 from overcharging, excessive discharge and, if necessary, protects against overload peaks. The wiring system management system 9 is also via an information system 10 with the hybrid control 2 connected. The information system 10 is known to be a bus system, such. B. a CAN bus.

A display device 12 , which can provide a variety of information to the driver, and is designed for example as an instrument cluster, is either directly with the electrical system management system 9 or via the information system 10 connected to the current state of charge of the high-voltage energy storage 7 and / or the low-voltage battery 15 to submit and display. The electrical energy is displayed either separately for each voltage network or as a total energy balance.

According to the invention, the electronic control 1 for transmitting information directly to the advertising device 12 connected. The information about the vehicle's own bus system is preferred as an information system 10 , as in 1 presented, transmitted. Alternatively, the information provided by the electronic controller 1 have been calculated by the hybrid controller 2 to the display device 12 transmitted via an existing information channel.

The 2 shows simplified method steps of the method according to the invention, the control 1 performs. The method according to the invention is started at S1 as soon as the vehicle operation is started for driving with the vehicle. This happens, for example, in which an ignition key is inserted into the ignition lock and turned or a start button is pressed.

In a second step S2, the controller asks 1 from the on-board network management system 9 the current state of charge, the target minimum and desired maximum state of charge of the at least two energy storage, the high-voltage energy storage 7 and the low-voltage battery 15 from.

This information is used in step S3 of the hybrid control to adapt the operating strategy and the display device 12 transmitted to the driver for display and on the display device 12 displayed.

In step S4 is a discharge current, for example, from the operation of the electric machine 4 and / or consumers 14 essentially results in the low-voltage network, measured as energy quantity output per defined time unit.

In step S5 is a charging current as an energy quantity input per defined time unit, by a regenerative operation of the electric machine 4 is generated, measured. The charging current is at the high-voltage energy storage 7 and at the low-voltage battery 15 measured. Both values of the high-voltage and low-voltage on-board subnetwork are processed separately and combined.

in the Step S6 will take a required amount of residual energy until the Reaching a maximum state of charge of the two electrical energy storage as Remaining load duration and as the remaining kilometer or the minimum charge state the two energy storage also as the remaining time or as a minimum Remaining kilometers calculated. To avoid strong fluctuations, "moving Means ", that is a sum of several Measured values that were averaged are calculated.

In step S7, the information calculated in step S6 is sent to the hybrid controller 2 for the operating strategy and the display device 12 submitted for issue. The hybrid controller 2 fits the controller based on the information 1 the operating strategy. The driver can adjust his driving style based on the display and optionally decide whether he wants to take additional resources of the battery to achieve certain destinations more advantageous. The current state of charge and the amount of residual energy to both Maximas is shown summarized by two energy storage and / or the values determined are for the high-voltage energy storage and low-energy storage separately by means of the display device 12 presented to the driver.

In a query 1 it is determined whether the vehicle operation is still maintained. If this is the case, the control returns to step S2, in the other case, the process is terminated.

The 3 shows a state of charge-time diagram of a single electrical energy storage, either the high-voltage energy storage 7 or the low-voltage battery 15 can be.

The state of charge-time diagram is correspondingly transferable to both electrical energy storage. On the abscissa, the time t is plotted, for example, represents a period of 2 to 5 minutes and on the ordinate is the state of charge (SoC) of the battery 7 shown in percent.

The state of charge-time diagram of 3 shows a linear characteristic P with a current state of charge (SoC) at the start time t _0, for example, 45% and a maximum achievable state of charge, for example, 70%. The starting point is called t ₀ 45 and the end point is called SoC70P. Conventional energy storage, such as a high-voltage storage, is conventionally discharged and charged between, for example, 30 and 70% of the actual state of charge. The unloading and loading controls, as already explained above, the on-board network management system 9 , A gradient triangle 31 , with constant energy input per unit time, defines the slope of the proportional characteristic P.

A characteristic E approximating an exponential curve is obtained by several exponentially sutured slope triangles 32 . 33 Are defined. The gradient triangles 32 . 33 are thus calculated successively.

A high-voltage energy storage 7 is not linearly chargeable per unit of time as represented by the characteristic curve P, but due to the decreasing voltage across the increasing charge, there is an exponential approach, as represented by the characteristic curve E. Thereafter, the point SoC70E of a maximum state of charge with constant driving with constant amount of energy input per unit time, earlier in time before the time t _PM of the exponential curve E at time t _{EM is} reached. The control 1 calculates the earlier time t _EM as a "moving average" at defined, recurring time intervals, a remaining time for a corresponding amount of residual energy until reaching a desired maximum value of the state of charge of the high-voltage energy storage 7 is needed. Accordingly, the remaining time until reaching a target minimum value of the state of charge of the high voltage energy storage 7 calculated from a corresponding amount of residual energy. These remaining time values can also be converted into remaining kilometers. They are used either as remaining time values or as residual kilometers or both of the hybrid control 2 provided for the adaptation of the operating strategy and on the display device 12 shown. Thus, a resource-saving driving style is directly influenced by the driver or by one of the hybrid controller 2 adapted operating strategy possible.

All Figures show only schematic not to scale Representations. Incidentally, in particular, the graphic Illustrations for the invention as essential.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 60024924 T2 [0007]
• - DE 10029886 C1 [0009]
• - DE 4339568 A1 [0010]

Claims (10)

Method of electronic control ( 1 ) in a motor vehicle, in particular with a hybrid drive, with at least one electrical energy store, in particular a high-voltage energy storage ( 7 ) and / or a low-energy energy storage and an on-board network management system ( 9 ) (BMS) comprises, with electrical consumers, at least one electric machine ( 4 ) as a prime mover and as a generator, wherein the current state of charge of the energy storage is continuously queried and classified within a minimum and maximum state of charge, the requested information on the state of charge on a display device ( 12 ) are output to the driver, characterized in that a required amount of residual energy is calculated until reaching at least one permissible setpoint extreme value of the state of charge of the energy store and is transmitted as information of at least one vehicle device. A method according to claim 1, characterized in that the required amount of residual energy as an exponential approach depending on controlled variables, in particular the current state of charge of the energy storage and an incoming moment on the generator or a charging current of a generator, and on a low-voltage electrical system hanging consumers ( 14 ), which are connected via a DC / DC converter ( 16 ) from a high-voltage vehicle electrical system from the high-voltage energy storage ( 7 ) is charged with energy. Method according to claim 1 or 2, characterized that the residual energy amount is calculated from "moving averages" becomes. Method according to one of the preceding claims 1 to 3, characterized in that the amount of residual energy up to Reaching a maximum state of charge of the energy storage is calculated. Method according to one of the preceding claims, characterized in that the residual energy amount until reaching a minimum state of charge of the energy store ( 7 ) is calculated. Method according to one of the preceding claims, characterized in that the required amount of residual energy until reaching at least one extreme value of the state of charge of the energy store ( 7 ) is calculated as the remaining time and / or as the remaining kilometer and in particular to the driver in the display device ( 12 ) are displayed. Method according to one of the preceding claims, characterized in that the residual energy amount until reaching at least one extreme value of the state of charge of the energy store ( 7 ) a drive control, in particular a hybrid control ( 2 ) as information for adaptation to an operating strategy. Method according to one of the preceding claims 1 to 7, characterized in that the calculated information with date and time defined according to an operating strategy the vehicle stored and in particular to a defined Time can be read according to the operating strategy. Computer program product which is stored in a program memory of a controller ( 1 ) is loadable with program instructions to perform all the steps of a method according to at least one of claims 1 to 8, when the program is executed in a control of a motor vehicle. Electronic control ( 1 ) for a motor vehicle, in particular with a hybrid drive, with a program memory and an electronic computer, the information about the state of charge of an energy store ( 7 ), in particular a battery in the motor vehicle and transmitted to at least one vehicle device for output or further processing, wherein the control device ( 12 ) performs the method according to one of claims 1 to 8, in particular by means of a computer program product according to claim 9.