DE102007020935A1 - Method for drive control of hybrid vehicles comprises a device having combustion engine, electro machine,electrical energy source which is loaded via generated power from electro machine which is driven by combustion machine - Google Patents

Abstract

The method for drive control involves a device (1) with at least one combustion engine (2) and one electro-machine (3) and at least one electrical energy source (4), where the energy source is loaded via generated power from the electro-machine. The electro-machine is driven by the combustion engine or, in the recuperation function in the retardation phase of the hybrid vehicle, from a gear. The electrical energy source has a system for determining or transmitting the temperature of the energy source and a system for transmitting alterations (SOH).

Description

The The invention relates to a method and a device for the drive control of hybrid vehicles at high load of a electronic energy storage.

at Hybrid vehicles are combined with two drive units, in different ways the power for the vehicle drive provide. The properties complement each other particularly well an internal combustion engine and (at least) an electric machine, why hybrid vehicles today predominantly with such Combination be equipped. The connection of the electric machine To the engine crankshaft can be done in different ways. So this can be a clutch or directly to the crankshaft connected to the engine or via a belt drive or a Gearbox be coupled. The control of the electric machine is done via a control unit (inverter, power electronics).

When Electric energy storage in hybrid vehicles usually deep cycle batteries using NiMH or Li-Ion technology. The life of the battery is u. a. about the enforced (i.e., stored and stored energy) and the power or limits the energy swing during the charging or discharging process. A strong cyclization leads beyond that to an accelerated aging of the battery. It comes next the heating of the battery by environmental influences (eg high outside temperatures or strong sunlight) in hybrid driving due to the lossy energy throughput to an additional warming.

to Avoidance of unacceptably severe aging will increase energy throughput therefore in known hybrid systems at higher temperatures limited to slow the temperature rise. This is in parallel with a limitation of hybrid functions connected. When an upper, critical limit temperature is reached Finally, the energy throughput must be almost complete be reduced, which essentially only a backup the basic vehicle functions (such as the initial start, for example).

moreover is to increase the battery life of the state of charge (SOC) of the battery whenever possible in a narrow window adjusted by the nominal charge state. Here, the aim is the SOC in a window + -25%, preferably + -15% and more preferred + -10% to keep the nominal charge. As in real driving This operating window usually does not automatically result as a result the changing motor and generator operation of the electric machine is set, specific functions are activated to the permissible operating window observed.

A Discharge of the battery takes place (in addition to the supply of the electrical system and operation of additional electrical consumers) in particular by motor operation of the electric machine. So can preferably in Areas with only low load requirements, where an internal combustion engine only has low efficiencies, a purely electric drive of Vehicle done. In addition, the torque delivery From combustion engine and electric machine also be done in parallel, for example to increase the maximum torque of the entire drive (boost mode).

Of the Electromotive operation with high power requires control with an appropriate strategy that limits the limited capacity of the electrical energy storage considered. specially During boost mode, on the one hand, a clear improvement in driving performance is to be achieved achieved on the other hand, but also a reproducible driving are shown, in particular in multiple activation in short time sequence.

The Charging of the energy storage is done from an energetic point of view preferably over Recuperation, d. H. regenerative operation of the electric machine in deceleration phases of the vehicle. For a high energy recovery to achieve, is in particular during braking a high electrical power required to get the largest possible Share of otherwise converted into heat in the wheel brakes To feed back braking energy. In addition, can even when the combustion engine is running due to generator operation the electric machine recharged the electrical energy storage become.

Next the mentioned functions e-driving, boost and recuperation As a rule, hybrid vehicles also have a start-stop function (Shutdown of the engine when the vehicle is stationary) and often also a sailing function (switching off the internal combustion engine and opening the clutch when rolling vehicle) on.

In both phases is the supply of the electrical system and, where appropriate additional electrical additional consumers from the energy storage to ensure.

A required reduction of the energy throughput, for example when a battery temperature is exceeded by limiting hybrid functions, can be achieved not only by limiting the permissible duration of the functions but also by reducing the maximum power. It can either all functions are limited to a lump sum or - if necessary - initially only one or a few functions. For example, the maximum power could first be reduced in the boost function since it typically requires high electrical power. However, that would very quickly lead to lower mileage, although this might not be necessary immediately. On the other hand, the driver could then z. B. predominantly the e-driving function can be used, so that the restriction of the boost function would bring in this case in terms of battery load no improvement.

alternative or in addition, the duration and / or Limit power of the electric machine in purely electric driving, giving the achievable speed and / or range in restricted in this operating mode.

Of Furthermore, the permissible durations of the Phases in which the electrical system is supplied from the hybrid storage, be shortened. Optionally, here too the performance be limited if the electrical system then additionally or alternatively it is supplied from an on-board battery or the power consumption of the electrical system is restricted (eg by targeted Consumer shutdown).

As a general rule These methods have the disadvantage that the hybrid functions all-inclusive must be restricted because the following Operating behavior of the vehicle is not predictable. As a result is very quickly a limitation of the hybrid functionality a, what for the driver to a less reproducible Driving behavior leads.

From the DE 44 03 468 C2 a method for monitoring the extraction current for traction batteries in electric and hybrid vehicles is known, wherein the maximum allowable bleed current is adjusted depending on operating parameters to a permissible value for continuous operation, the average battery temperature is compared with a predetermined critical temperature limit and only then, if the mean battery temperature exceeds the critical limit temperature, the bleed current is reduced to an allowable continuous bleed current.

From the DE 103 46 720 A1 For example, there is known a vehicle control apparatus for reliably preventing the generation of variations, which improves the setting of a limit, and which is capable of realizing a stable motor drive regardless of the condition of a battery. Therefore, an electronic control unit executes a control for a vehicle including a motor and a battery for supplying electric power to drive the motor, whereby the regenerative electric power of the motor can charge. The electronic control unit has a battery judging means and a temperature detecting means each for detecting the SOH (health status) of the battery and the outside air temperature around the battery (or the temperature of the battery itself). The electronic control unit further includes threshold value setting means for respectively setting upper and lower limit values for a voltage value and an electric current value at the output of the electric power from the battery, and a voltage value and an electric current value at the supply of the regenerative electric power to the battery according to the detected one SOH and outside air temperature.

Of the Invention is the technical problem underlying a method and a device for the drive control of hybrid vehicles to create at high battery load, by means of which a reproducible Driving behavior can be realized.

The Solution of the technical problem results from the objects with the features of claims 1 and 4. Further advantageous Embodiments of the invention will become apparent from the dependent claims.

For this includes the hybrid vehicle or the device for drive control at least one internal combustion engine, at least one electric machine and at least one electrical energy store, wherein the electrical Energy storage by a generator operation of the electric machine is charged, the electric machine either from the internal combustion engine is driven or in a Rekuperationsfunktion in deceleration phases of the hybrid vehicle is driven by a transmission, wherein the electrical energy storage means for detecting or determining the temperature associated with and / or the electrical Energy storage means for determining the aging (SOH) is assigned, depending on the detected or determined temperature and / or a degree of aging only the regenerative Operation of the electric machine limited in terms of performance with the performance and / or allowable duration of the hybrid basic functions depending on the state of charge of the energy storage (SOC) are executed.

In this way, it is achieved that the reduced recharge of the energy storage leads on average to a lower SOC. The electrical energy consuming functions such. The boost functions, for example, indirectly achieve power limitation through their SOC dependency and / or the duration.

Becomes in the following driving, for example, predominantly used the boost function and little electric driving or Stop operation realized, so the boost function can be longer or be used with higher benefits than one Procedure with blanket limitation of several functions, here also reserves for the other functions such. B. E-driving are required.

Becomes The vehicle then predominantly consumption-oriented z. B. at lower speeds, so leads the new functionality that is consumption-reducing Functions such as e-driving or start-stop operation longer can be used.

By the proposed method becomes the function restriction to reduce the load on the electrical energy storage So implemented as needed and the driver at the same time in terms as long as possible on the hybrid functionality reproducible handling or the largest possible Savings potential possible.

there It should be noted that at the temperature preferably by exceeding of limit values, the limitation of regenerative operation is triggered, with the limit (s) fixed or depending on the degree of aging. It should also be noted that the procedure does not preclude that when crossing another, higher Limit value for the temperature further performance restrictions be made. Furthermore, the procedure concludes do not rule out that the other hybrid basic features besides the SOC can still be dependent on other parameters, but not from the battery temperature and / or the degree of battery aging.

Preferably In addition, only the Rekuperationsfunktion performance limited.

The hybrid basic functions preferably comprise at least one Boost operation, electric driving and a start-stop and Sailing operation.

Of the electrical energy storage is preferably as a battery or capacitor storage educated.

The Battery is preferably a lead-acid battery, lead-gel battery, NiMH or Li-ion battery formed.

The Invention will be described below with reference to a preferred embodiment explained in more detail. The only figure shows one schematic arrangement of a device for controlling the drive of a hybrid vehicle.

The device 1 for driving control of a hybrid vehicle comprises an internal combustion engine 2 , an electric machine 3 , a battery 4 and a gearbox 5 , The connection of the electric machine 3 To the engine crankshaft can be done in different ways, for example via a clutch 6 , or directly connected to an engine crankshaft or be coupled via a belt drive or a transmission. The connection of the electric machine 3 to the gearbox 5 via a coupling 7 , which is preferably designed as a double clutch or as a converter. Furthermore, the battery 4 with the electric machine 3 connected to unillustrated inverter and power electronics. The battery 4 is a facility 8th for determining the battery aging SOH and a device 9 assigned to determine the battery temperature T _Bat , which either determines the battery temperature T _Bat itself or derived from the ambient temperature this. The internal combustion engine 2 An unillustrated engine control unit is assigned. Likewise, the gearbox 5 a transmission control unit and the electric machine 3 assigned to a control unit. One of these control units, preferably the engine control unit or a higher-level hybrid control unit, have the. Software for the operating strategy. The facilities 8th . 9 then supply the SOH and the battery temperature T _Bat via a bus or directly to the controller that sets the operating strategy. If the battery temperature T _Bat then _exceeds a first limit value and / or the SOH falls below a limit value, then the generator operation of the electric machine becomes 3 limited in performance, whereas the performance and / or duration of the other basic hybrid functions depends on the state of charge SOC of the battery 4 be executed. It can further be provided that, when exceeding or falling below second limit values for T _Bat or SOH, the regenerative power or the hybrid basic functions are further restricted.

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 4403468 C2 [0015]
• DE 10346720 A1 [0016]

Claims (8)

Method for the drive control of hybrid vehicles at high load of an electrical energy storage device, by means of at least one internal combustion engine, at least one electric machine and at least one electrical energy storage, wherein the energy storage is charged by a generator operation of the electric machine, wherein the electric machine is either driven by the internal combustion engine or in a recuperation function in deceleration phases of the hybrid vehicle is driven by a transmission, wherein the electrical energy storage is associated with a device for detecting or determining the temperature of the energy storage and / or the electrical energy storage device is associated with a device for determining the aging (SOH), characterized in that depending on the detected or determined temperature (T _Bat ) and / or a degree of aging (SOH) only the regenerative operation of the electric machine ( 3 ) is limited in performance, wherein the power and / or allowable duration of the other hybrid basic functions depending on the state of charge of the electrical energy storage (SOC) are performed. Method according to claim 1, characterized in that that only the recuperation function in terms of performance is limited. Method according to claim 1 or 2, characterized that the hybrid basic functions at least one boost operation, electric driving and start-stop and sail operation. Device for the drive control of hybrid vehicles at high load of an electrical energy storage, by means of at least one internal combustion engine, at least one electric machine and at least one electrical energy storage, wherein the energy storage is charged by a generator operation of the electric machine, wherein the electric machine is either driven by the internal combustion engine or in a recuperation function in deceleration phases of the hybrid vehicle is driven by a transmission, wherein the electrical energy storage is associated with a device for detecting or determining the temperature of the energy storage and / or the electrical energy storage device is associated with a device for determining the aging (SOH), characterized in that depending on the detected or determined temperature (T _Bat ) and / or a degree of aging (SOH) only the regenerative operation of the electric machine ( 3 ) is limited in performance, wherein the power and / or allowable duration of the other hybrid basic functions depending on the state of charge of the electrical energy storage (SOC) are performed. Device according to claim 4, characterized in that that only the recuperation function in terms of performance is limited. Apparatus according to claim 4 or 5, characterized that the hybrid basic functions at least one boost operation, electric driving and start-stop and sail operation. Device according to one of claims 4 to 6, characterized in that the electrical energy store is designed as a battery or as a capacitor storage. Device according to claim 7, characterized in that that the battery is a lead-acid battery, lead-gel battery, NiMH battery or Li-ion battery is formed.