DE10100889A1 - Implementing start/stop operation of vehicles involves using two sub-supply systems, each containing an energy storage device, for supplying power when the motor is idle - Google Patents

Abstract

The method involves using two sub-supply systems (1,2), each containing an energy storage device, for supplying power when the motor is idle. Batteries are used for energy storage and the energy required for a start or a warm start is supplied by a first sub-supply system. Energy for the on-board loads is supplied by the second system. Independent claims are also included for the following: an energy supply device for a vehicle operated in start/stop mode.

Description

The invention relates to a method and a device to implement a start / stop operation for vehicles gene.

State of the art

From WO 98/19890 an on-board power supply control device is known which has a supply power supply, a short-circuit-proof output stage, a control and regulating unit and a DC voltage converter. This vehicle electrical system control unit is connected between the vehicle electrical system battery and the starter battery of a motor vehicle. The starter battery can be supplied as needed via the DC voltage converter from the vehicle electrical system side in such a way that temperature-adjusted, both a higher and a lower or the same charge voltage level can be generated compared to the vehicle electrical system voltage. In this known on-board power supply control unit, both batteries are connected in parallel in the case of an empty on-board power supply battery via the switches 14 a and 14 b provided there. This can lead to the starter battery being discharged very far, so that the required battery power is not always ensured in the case of short successive starting processes.

DE 34 23 663 A1 describes a device for starting and turning off a starter-powered burner known engine in a vehicle. With this, The device is the internal combustion engine when present a definable combination of input variables and / or Switched off states and at least when actuated a switch by turning on the starter motor like the tempered. In addition, the known before direction of a starting process even with simultaneous luff against a driving speed of the vehicle above one definable limit value and actuation of the vehicle brake pedal. This ensures maintenance when the vehicle is rolling of the brake vacuum of the servo brake guaranteed, however only if the driver is responsive and with the Foot depressed the brake pedal.

Advantages of the invention

The inventive method with the features of the Say 1 has the advantage that in the start / stop mode of the Vehicle a more stable energy supply without interference the start / stop function is guaranteed. This is achieved in that the energy supply during motor downtimes using two parts supply networks, each with an energy storage contain. The state of charge of the energy storage of the supply network, which is used to supply the starter or Starter generator, can be controlled that the energy required to start the vehicle is always present. During the engine running time after one A warm start can then be a result of the energy storage Charge deficit can be quickly compensated.  

For this purpose, it is advantageously located in the Partial supply network, which supplies the starter or starter generator is also used to charge the Ener Giespeicher this partial supply network provided Ge erator. This can be an independent generator or the starter generator for the start itself. Such star Tergenerators can be based on a claw pole machine with belt drive or based on an asynchronous machine or synchronous machine can be realized. In the event that the Starter generator cannot start is one too additional starter in one of the two partial supply networks provided. When determining the loading strategy or the Charging characteristic for the energy storage of the partial supply network, which supplies the starter or starterge nerators advantageously does not need a return view of any restrictions and specifications other individual consumers are taken as in this Partial supply network either no other individual supply need or only insensitive to voltage fluctuations che further consumers are provided. In particular, can the loading strategy should be such that using a high Charging voltage of the energy store is charged in a short time becomes. This ensures that even at low outside temperatures and frequent start / stop processes energy required to start the engine stands.

Charging the energy store of the second partial supply network, which preferably the on-board battery of the driver contains stuff, takes place during the engine running times via egg NEN DC converter also from the generator or Starter generator, through which the starter battery is loaded. During engine downtimes, the  On-board network battery as long as possible from the starter battery be taken care of until the state of charge of the starter battery falls below the predetermined threshold. By means of the On-board power supply batteries are used during engine downtimes Consumers in the electrical system energy reduced to a minimum supplies, for example lighting. Only when that Supply of the starter necessary voltage level straight can still be provided by the starter battery the co-supply of the on-board electrical system battery is interrupted. To slow down the discharge process of both batteries can gradually step in individual electrical system consumers Dependence on the voltage level of the starter battery be switched.

For further optimization of the loading or reloading strategy the energy storage in the partial supply networks is before preferably uses a control unit, which energy storage cher status signals, consumer status signals and tempe rature sensor signals are supplied. This control unit can be centrally located in the DC-DC converter integrated or provided with it or also in the Be richly arranged the generator or one of the batteries his.

drawing

An embodiment of the invention is shown in the drawing and is explained in more detail in the following description. Fig. 1 shows a schematic Dar position of a first embodiment for the inven tion. Fig. 2 shows a schematic representation of a second embodiment of the invention. Fig. 3 shows a more detailed illustration of the second embodiment, in which a control device is illustrated.

description

Fig. 1 shows a schematic representation of a he first embodiment of the invention. With this, the energy supply in start / stop mode, in which engine running times and engine downtimes alternate and in which a warm start of the vehicle takes place between an engine downtime interval and an engine operating time interval, is carried out as follows:
A starter generator SG, for example a 42 V starter generator, and a battery B1, for example a 36 V battery, form a first partial supply network 1 . The Star tergenerator SG is provided for performing the warm start. Accordingly, a separate starter for the cold start is provided in the partial supply network 2 . Consequently, the battery B1 primarily serves to provide the energy required for a warm start. If the starter generator SG also takes over the cold start, the battery B1 must also be designed for the cold start and the starter in the partial supply network 2 can be omitted.

An on-board power supply battery B2, for example a 12 V battery, is part of a second sub-supply network 2 . This is for supplying a starter AN and for supplying consumers V, for example lighting, radiator fan,. , ., intended. The possibly additional starter ON is only required for a cold start and is therefore irrelevant for the start / stop operation. Consequently, the battery B2 must supply the energy required for a cold start and, when the start / stop operation is activated, supply the consumers V with energy both during the engine downtimes and during the engine running times.

In a first embodiment of the first exemplary embodiment shown in FIG. 1, the two partial supply networks 1 and 2 are completely decoupled from one another in the start / stop mode during the motor downtimes. The battery B1 only has the task of providing the energy required for the starter generator SG for the next warm start of the vehicle. Other consumers are not supplied from battery B1 during engine downtimes. The battery B2 has the task during the engine downtime to supply the consumer V, for example a car radio, light and various control devices, with energy.

During the engine runtime, batteries B1 and B2 recharged. This reloading is done using the generated by the starter generator SG during engine running times energy.

Since in the partial supply network in which the battery B1 located, no further consumers are provided, can the recharge of this battery B1 with a view to optimized for the special type of battery used Charging strategy or charging curve take place quickly. there needs no consideration of any restrictions and specifications taken by other consumers the. Through this optimized for the respective battery type Recharging the battery B1 is advantageous is enough that in start / stop operation with low outside temperatures the duration of between two engine downtimes  required engine runtimes can be shorter than with known solutions. In such known solutions, where the loading strategy with regard to other Ver needs to be determined, can only be a relatively ge rings charging current take place, which leads to a comparative wise long charging leads.

The recharge of the battery B2 arranged in the partial supply network 2 , which is the on-board electrical system battery of the vehicle, takes place via the direct voltage converter 3 , which couples the two partial supply networks 1 and 2 only for the purpose of this recharge of the battery B2 during the engine running times.

In a second embodiment of the embodiment shown in FIG. 1, the battery B2 is also supplied without restriction via the DC converter 3 in the start / stop mode during engine downtimes until the voltage level of the battery B1 arranged in the first sub-supply network 1 has a predetermined first smoldering len value reached. This first threshold value is chosen so high that it is ensured that the energy required for a warm start can be made available by the battery B1 without any problems.

If the voltage level of the battery B1 falls below the given first threshold value, then the charging current transmission from the battery B1 via the direct voltage converter 3 to the battery B2 is limited and thus accepted that the battery B2 continues to discharge.

If the voltage level of the battery B1 continues to decrease and decrease if it exceeds a second predetermined threshold value,  then the power consumption is reduced. This can happen by happening that in the sense of a priority list Ver low priority users completely switched off the or that some or all consumers regarding their Power consumption can be reduced. This will make the Ent charging of both batteries slows down.

If the voltage level of the battery B1 drops further and falls below a third predetermined threshold value, the co-supply of the battery B2 is interrupted via the DC-DC converter 3 . This third threshold is set in such a way that it is further ensured that the battery B1 can provide the energy required for the starter generator SG for a start.

If the voltage level of the battery drops so far that the Execution of a warm start is no longer ensured the start / stop function is suppressed.

This second embodiment is also distinguished by the fact that it is always ensured that the state of charge of the battery B1 is so high that the energy required for a warm start for the starter generator can be made available in start / stop operation after an engine standstill phase. As long as the state of charge of the battery B1 is clearly above this limit, in this embodiment the second partial supply network 2 can also be supplied via the DC / DC converter 3 . This co-supply can be gradually reduced depending on the voltage level of the battery B1.

Also in this embodiment, the start / stop loading drove batteries B1 and B2 during engine running times recharged. This reloading is done using the generated by the starter generator SG during engine running times energy as already mentioned in connection with the first embodiment has been described.

Fig. 2 shows a schematic representation of a two-th embodiment of the invention. In this case, the energy supply takes place in the start / stop mode, in which engine running times and engine downtimes alternate and in which a warm start of the vehicle takes place between an engine downtime interval and an engine operating time interval, as follows:
A generator G, for example a 42 V generator, a battery B1, for example a 36 V battery, and the starter AN of the vehicle belong to a first partial supply network 1 of the vehicle. The starter AN is intended to perform cold starts as well as warm starts. Consequently, the battery B1 primarily serves to supply the energy required for the vehicle's starting processes.

An on-board power supply battery B2, for example a 12 V battery, is part of a second sub-supply network 2 . The ses is provided to supply the other electrical system consumers V, for example lighting, control units,. , .. This applies both during engine downtimes and during engine running times.

In a first embodiment of the second exemplary embodiment shown in FIG. 2, the two sub-supply networks 1 and 2 are completely decoupled from one another in the start / stop mode during engine downtimes.

The battery B1 only has the task to the next Warm start of the vehicle required energy for the starter To make available. Other consumers are being selected during engine downtimes not from battery B1 provided. The battery has B2 during engine standstill times the task reduced to a minimum Consumer V, for example a car radio, light, control devices or a car phone to supply energy.

During the engine runtime, batteries B1 and B2 recharged. This reloading is done using the generated by generator G during engine running times strategy.

Since in the partial supply network in which the battery B1 located, no further consumers are provided, can the recharge of this battery B1 with a view to optimized for the special type of battery used Charging strategy or charging curve take place quickly. there needs no consideration of any restrictions and specifications obtained from other consumers the. Through this optimized for the respective battery type Recharging the battery B1 is advantageous is enough that in start / stop operation with low outside temperatures the duration of between two engine stops required engine runtimes can be shorter than with known solutions. In such known solutions, where the loading strategy with regard to other Ver needs to be determined, can only be a relatively ge rings charging current take place.  

The recharge of the battery B2 arranged in the partial supply network 2 , which is the on-board electrical system battery of the vehicle, takes place via the direct voltage converter 3 , which couples the two partial supply networks 1 and 2 only for the purpose of this recharge of the battery B2 during the engine running times.

In a second embodiment of the embodiment shown in FIG. 2, the battery B2 is also supplied without restriction via the DC converter 3 in the start / stop mode during engine downtimes until the voltage level of the battery B1 arranged in the first partial supply network 1 has a predetermined first smoldering len value reached. This first threshold value is chosen so high that it is ensured that the energy required for a warm start can be made available by the battery B1 without any problems.

If the voltage level of the battery B1 falls below the given first threshold value, then the charging current transmission from the battery B1 via the direct voltage converter 3 to the battery B2 is limited and thus accepted that the battery B2 continues to discharge.

If the voltage level of the battery B1 continues to decrease and decrease if it exceeds a second predetermined threshold value, then the power consumption of some or all of the board network consumers reduced. This can happen that in terms of a priority list consumers are lower Priority to be turned off completely or that some or all consumers regarding their power consumption  be reduced. This will unload both of them Batteries slowed down.

If the voltage level of the battery B1 drops further and falls below a third predetermined threshold value, the co-supply of the battery B2 is interrupted via the DC-DC converter 3 . This third threshold is set in such a way that it is further ensured that the battery B1 can provide the energy required for the starter AN to start.

If the voltage level of the battery B1 drops so far that the execution of a start is no longer ensured the start / stop function is suppressed.

This second embodiment is also distinguished by the fact that it is always ensured that the state of charge of the battery B1 is so high that the energy required for the starter to start can be provided in start / stop operation after an engine standstill phase. As long as the state of charge of the battery B1 is clearly above this limit, in this embodiment the second partial supply network 2 can also be supplied via the direct voltage converter 3 . This co-supply can be gradually reduced depending on the voltage level of battery B1.

Also in this embodiment, the start / stop loading powered batteries B1 and 82 during engine run times recharged. This reloading is done using the generated by generator G during engine running times gie as already mentioned above in connection with the first Embodiment has been described.  

Fig. 3 shows a more detailed representation of the two th embodiment, in which a control unit ST is illustrated. By means of this control unit ST, which can also be used in a corresponding manner in the exemplary embodiment shown in FIG. 1, the recharging process of the batteries B1 and B2 is controlled by controlling the generator G and the DC voltage converter 3 . This is done using additional information that is supplied to the control unit.

This additional information includes information about the state of charge and aging and the temperature of the bat series B1 and B2. Further additional information is consumption status signals and information about the status of the Generator G. Furthermore, the control unit ST uses Op Timing of the reloading also signals that it the vehicle bus CAN, for example from the engine control unit, are supplied and signals from other sensors be derived. Such other sensors are in for example temperature sensors for detecting the outside temperature temperature and sensors for detecting the speed of movement vehicle.

In the case of on-board electrical systems with electrical energy management, which will in future be designed as 14 V / 42 V on-board networks, and which may also be purely 42 V on-board networks, the control unit ST controls using the above-mentioned additional information and information about the Types of batteries B1 and B2 the generator G and the DC-DC converter 3 in the sense of an optimized charge of the batteries B1 and B2.

A dynamic adjustment of the energy flow between between the two partial supply networks depending on the type and number of consumers currently switched on respectively. For example, if there are currently no voltage sensitive consumer is switched on and the engine is running, then the charging voltage can be raised, in particular at low outside temperatures, regardless of Ver need to take so that the store B2 faster can be reloaded.

Further, in the parts supply network 1, there when a 42 V-generator is used, and 42 V loads be contained ten. However, these may only be consumers that are insensitive to strong voltage fluctuations. This must be taken into account because a wide range of charging voltages should be permitted for fast charging of the battery B1.

Regarding the positioning of the control unit is shown pointed out that the control unit in systems with electrical energy management can be arranged centrally can. Furthermore, the control device can the DC voltage converter provided or integrated into this. Further can the control unit near the generator or in the Be placed near one of the batteries.

Claims (20)

1. A method for ensuring the energy supply in a vehicle with start / stop operation, in which engine running times and engine downtimes alternate, characterized in that the energy supply takes place during engine downtimes using two partial supply networks, each of which contains an energy store. 2. The method according to claim 1, characterized in that Batteries are used for energy storage. 3. The method according to claim 1 or 2, characterized net that that needed for a start or warm start Energy from the first of the two partial supply networks finished. 4. The method according to claim 3, characterized in that the energy required for the electrical system consumers in front two partial supply network is supplied. 5. The method according to claim 4, characterized in that the voltage level of the energy storage contained in the first partial supply network is monitored and included in the second sub-supply network electrical system consumers for so long from the first partial supply network without restrictions until the Voltage level of that contained in the first partial supply network  Energy storage a predetermined first thresholds worth less. 6. The method according to claim 5, characterized in that then when the voltage level of the in the first partial supply supply network contained the specified he falls below the maximum threshold for co-provision of the second sub-supply network transmitted charging current be is bordered. 7. The method according to claim 6, characterized in that then when the voltage level of the in the first partial supply supply network contained a second pre falls below the given threshold, which is smaller than the first threshold, a shutdown of no mandatory electrical system consumers. 8. The method according to claim 7, characterized in that then when the voltage level of the in the first partial supply supply network contained a third pre falls below the given threshold, which is smaller than the second threshold, the co-provision of the second Partial supply network is interrupted. 9. The method according to any one of claims 5-8, characterized ge indicates that the threshold values are temperature-dependent be specified. 10. The method according to any one of claims 5-9, characterized ge indicates that the co-provision of the second part supply network included consumers from the first Partial supply network via a DC converter follows. 11. The method according to any one of claims 1-4, characterized ge indicates that the two partial supply networks during the engine downtimes are decoupled from each other.   12. The method according to any one of the preceding claims, there characterized in that during the engine running times of the Energy storage contained in the first partial supply network using one also in the first partial supply network contained generator is reloaded. 13. The method according to claim 12, characterized in that that during the engine running times that in the second partial supply energy network contained in the DC voltage voltage converter using the one in the first partial supply generator network is recharged. 14. The method according to any one of the preceding claims characterized by that energy supply during the start / stop operation controlled by a control unit what energy storage state signals, consumers status signals and temperature sensor signals supplied to who the. 15. Device for supplying energy to a vehicle with start / stop operation, in which engine running times and engine downtimes alternate, with a first partial supply network ( 1 ) and a second partial supply network ( 2 ), each of which has an energy store (B1; B2), whereby both energy supply networks are used for energy supply during engine downtimes. 16. The apparatus according to claim 15, characterized in that the first partial supply network ( 1 ) either one of the sem energy storage (B1) parallel starter generator (SG) or one of the energy storage (B1) connected in parallel generator (G) and one of the generator also starter connected in parallel (AN). 17. The apparatus according to claim 16, characterized in that the first partial supply network ( 1 ) a starter generator and the second partial supply network ( 2 ) additionally a starter (AN), for. B. for the cold start. 18. Device according to one of claims 15-17, characterized in that a DC voltage converter ( 3 ) is provided between the two partial supply networks. 19. The device according to any one of claims 15-18, characterized in that the second sub-supply network ( 2 ) is the on-board electrical system battery of the vehicle, which is used to supply the on-board electrical system consumers (V). 20. Device according to one of claims 15-19, characterized characterized that it has a control unit (ST), which input connections for energy storage status signal signals, consumer status signals and temperature sensor signals le, and which to control the energy supply during start / stop operation.