EP2148084A2 - Method and start controller for starting a combustion engine using a starter - Google Patents

Abstract

The method involves controlling the starter current in the starting process by the starter controller (4) in a defined manner. The starter current is synchronized by the starter controller of the starter (1), so that the starter is operated at a defined current value. The starter is charged by the starter controller with a variably adjusted starter voltage in defined manner. Independent claims are included for the following: (1) a computer program product for executing the method; (2) a starter controller with control electronics; (3) an on-board electrical system for a motor vehicle; and (4) an on-board electrical system module device for a motor vehicle.

Description

The invention relates to a method for starting an internal combustion engine of a vehicle by means of a starter and a starter control connected thereto. The invention further relates to a computer program product on a starter control with control electronics for a starter for starting an internal combustion engine in a vehicle, wherein in particular in the starter control method according to the invention, preferably by means of a computer program product is executed. Furthermore, the invention relates to a vehicle electrical system for a motor vehicle with a first constant lower voltage sub-network for a consumer and / or energy storage and a second variable high voltage sub-network for at least one multi-voltage generator.

The invention further relates to a vehicle electrical system module device for a motor vehicle with a DC / DC converter, a controller for a multi-voltage generator and an electrical energy store with a high voltage.

It is known to start an internal combustion engine by means of a starter. The starter is conventionally designed as a direct current machine and is directly connected to the battery with a voltage between 12 and 14 V, depending on the state of charge. The starter is manually operated by a simple switch by means of a control relay either by turning the ignition key controlled or electronically by a start button control.

It is known, especially in hybrid vehicles, to operate starters in a vehicle electrical system with a voltage greater than 14 V. Further, start-stop and recuperation systems are known from hybrid vehicles, which include at least one multi-voltage generator, double-layer capacitors (DLC) and a DC / DC converter (DC / DC converter). The starter is an electric machine that can also work as a generator and can be used as an integrated starter generator. The integrated starter generator is in a subnet with a higher voltage z. B. 14 - 32 V for motor vehicles and 14 - 42 V arranged for commercial vehicles. Such a multi-voltage electrical system, for example, in the DE 103 30 703 A1 described. Furthermore, the following prior art is known.

The DE 41 38 943 C1 describes a power supply for a vehicle with two voltage memories, wherein a starter is supplied only by a voltage storage. During the starting process, the starter is disconnected from the rest of the electrical system with the aid of a charging / disconnecting module.

The DE 10 2005 051 433 A1 describes a method and a device for controlling a generator in a two-voltage electrical system of a motor vehicle with a first voltage circuit, the generator is associated with a capacitor and whose voltage level is variably controlled within a voltage interval depending on the operating conditions of the vehicle and with a second voltage circuit whose voltage level is at the lower limit of the voltage interval and to which a battery is assigned.

The DE 102 31 517 B4 describes a vehicle electrical system and a method for operating a vehicle electrical system for a motor vehicle with at least a first and second voltage level and a generator. The first and second voltage levels are interconnected via a coupling device coupled, which comprises a series regulator, to which a DC / DC converter is connected in parallel.

It is an object of the present invention, a method, a computer program product, a starter control, a vehicle electrical system and a vehicle electrical system module of the type mentioned in such a way to use a starter with high power and with a low mechanical electrical load more efficient when starting an internal combustion engine.

According to the invention the object is achieved by the subject matter of claims 1, 6, 7, 8 and 10. Further advantageous developments emerge from the dependent claims.

An idea of the invention is to control the starter current in the starting process and not directly connect to the battery or to an energy storage. Instead, in contrast to the prior art, a starter control between battery and starter is switched.

The object is achieved by means of the method in that a starter current is controlled in the starting process of the starter control, which includes electronic components defined. This avoids that starter with a very high starter current, which is for example 800 to 1000 amps, is charged in the starting process. The starter current is preferably reduced by the starter control to a smaller starter current.

The object is achieved by means of a starter control for a starter for starting an internal combustion engine in a vehicle in that the starter control comprises a current control device with which the starter current can be regulated by a defined current value. This has the advantage that the life of the starter by the current control and possibly by an additional voltage regulation increases significantly. The starting comfort is improved by a voltage regulation, since noises the starter and vibrations are reduced. In addition, a voltage dip in the electrical system during a warm start, for example, in a start-stop operation better avoided. In addition, the starting speed of the internal combustion engine at a start-stop operation with energization of the starter to a defined current value over a longer period in the starting process improves because the power strokes are achieved earlier with top dead centers in the engine by a faster crank movement.

According to a further development of the invention, the starter current is clocked by the starter control of the starter, so that the starter is operated by a defined current value during the starting process. The starter current drives the starter in the first fractions of a second in the starting process, for example, with a nearly constant current value between 400 and 600 amperes. By reducing the starter current, the wear on the brushes and on the commutator decreases. The noise of the starter is also lower. The starter current is passed clocked to the starter, so that the starter current is operated within a tolerance band by the predetermined current value. If the current consumption of the starter exceeds a specified current value of the tolerance band, then the timing starts to interrupt the current. If a current drop at the lower threshold of the tolerance band is detected at the starter current, the interruption is canceled and the starter is re-energized.

To achieve a performance gain from a conventional starter, the starter is defined by the starter control with a variable adjustable starter voltage defined. The voltage at the starter can thus be significantly higher than the usual battery voltage of 12 to 14 V.

According to a further preferred method, the power output for starting the starter is regulated by means of the starter control from at least two energy stores, in particular technically differently constructed energy stores, particularly preferably a battery and / or at least a capacitor, taken. According to the invention, the starter control can thus control the electrical energy of two different energy stores and supply them to the starter. The starter control decides depending on the state of charge from which energy storage electrical energy is removed. For example, the one energy storage of the battery with a voltage between 12 and 14 V and the second energy storage at least one capacitor, more preferably a double-layer capacitor with a voltage of, for example, up to 42 V. Should the capacitor have sufficient electrical energy to use the starter to start the engine, the starter control will only discharge the capacitor. When a vehicle is to be started after a long standstill, the capacitor often has insufficient energy so that either the starter is powered directly by the battery, which controls the starter control. In an alternative method, the battery first charges the capacitor so that the starter restarts the engine with the energy of the capacitor. The energy supply in the starter controls the starter control according to the invention. It can also happen that the electrical energy for the starting process from the capacitor and the battery is combined. For example, to start the starter, the energy is first removed from the capacitor and then, when the capacitor is depleted, the energy is supplied from the battery.

In order to use the electrical energy for the starter as efficiently as possible, information is received at interfaces and processed by the starter control according to a preferred method, so that at least the starter current and / or the starter voltage is regulated as a function of the information. By way of example, signals can be recorded via a bus system, such as the LIN bus, or at terminal 50, for example, about the temperatures, state variables of components, for example the crankshaft speed and of an interface with the engine control, so that the starter current is correspondingly activated in dependence on these parameters , For this example, characteristics stored in the starter control, according to which the starter is operated by means of the starter control.

For example, the charge states and the temperatures are different in a warm start, as in a cold start, so that the required amount of electrical energy is different.

The starter control can be formed by exclusively electronic components. The starter control preferably has a microprocessor with a program memory.

The object is solved by means of a computer program product in that it can be loaded into a program memory with program instructions in order to execute all the steps of the method described above, when the program is executed in a starter control. This has the advantage that the starter control is variably adaptable to different starters and internal combustion engines. Furthermore, a fine adjustment or subsequent improvement of the method by means of improved, for example, empirically determined parameter values is easily possible.

According to an embodiment further developing the invention, the current control device in the starter control comprises a DC / DC converter. This has the advantage that the starter can also be operated at higher voltages than the usual battery voltage, so that the starting speed in the start-stop operation due to such a voltage increase in a performance increase of the starter. Thus, top dead centers of ignitable cylinders of the internal combustion engine are reached earlier, so that the internal combustion engine can be started faster.

The object is achieved by an electrical system in that at least one third independent, variable subnet is designed to control at least one consumer and / or energy storage. Because of that Starter can be switched as a consumer in a third independent variable subnet, the starter can be used efficiently, it can voltage dips are avoided and the starter can be from both an energy storage of a high voltage ie greater than 14 volts and an energy storage with a between 12 and 14 V can be variably and combined fed with electrical energy. Thus, the power loss of a vehicle electrical system is reduced, since the electrical energy can be highly efficient as a high voltage in energy storage, such as double-layer capacitors buffered for a certain time.

According to an embodiment further developing the invention, at least one fourth independent subnetwork is formed with at least one consumer and / or energy store. This has the advantage that, for example, a double-layer capacitor can be embodied as a separate energy store with a greater voltage or high voltage in an independent subnetwork and a controller can supply energy from both the fourth subnetwork and the first subnetwork to at least one consumer in the third or first subnetwork can.

In order to avoid voltage dips even better, according to a further preferred embodiment, the battery is designed for a low-voltage power grid in the first sub-network and a consumer for low-voltage in a fifth sub-network.

The object is achieved by means of a vehicle power supply module device for a vehicle that the DC / DC converter is designed as part of a particular starter control described above, at least two different subnets, a first subnetwork for the multi-voltage generator with a multiple voltage and at least a second subnet for a starter independently of each other. This has the advantage that a DC / DC converter, which in the vehicle power supply module device due to the multi-voltage generator in combination with two electrical energy storage, once for a high voltage and even for a low, constant Voltage of 12 volts to 14 volts, arranged can be filled with a second function. If the DC / DC converter does not work anyway in the starting process of the internal combustion engine, the DC / DC converter can take over the function of delivering a variable voltage to the starter to increase the starter power, with the starter current defined by a given current value is regulated, thereby accelerating the crankshaft of an internal combustion engine performs faster in time, so that the ignitable top dead center (TDC) in cylinders of the internal combustion engine are reached earlier than a conventional starter without a regulated ie an unregulated starter current. The starter and the at least one energy storage are less burdened by the defined control of the starter current than in a conventional manner. The lifetime of both components increases. The DC / DC converter only needs to be slightly modified and extended to control the starter current. Essential parts of the DC / DC converter can be advantageously used both for controlling the starter current and for regulating charging currents for at least one energy store in this dual function.

The method according to the invention can likewise be used advantageously in a hybrid vehicle in which, for example, the starter and the multi-voltage generator are designed as an electric machine.

It goes without saying that the features mentioned above and those yet to be explained below can be used not only in the respectively indicated combination but also in other combinations.

Short description of the figures

Fig. 1

einen schematischen Schaltplan eines Starters mit einer Startersteuerung,

Fig. 2

einen schematischen Schaltplan eines erfindungsgemäßen Bordnetzes gemäß einer ersten Ausführungsform,

Fig. 3

einen Schaltplan des Bordnetzes gemäß einer zweiten Ausführungsform und

Fig. 4

ein Zeit-Strom-Diagramm.

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

Fig. 1

a schematic circuit diagram of a starter with a starter control,

Fig. 2

a schematic circuit diagram of a vehicle electrical system according to the invention according to a first embodiment,

Fig. 3

a circuit diagram of the electrical system according to a second embodiment and

Fig. 4

a time-current diagram.

The Fig. 1 shows schematically and abstracted the electrical circuit diagram of a starter 1 for starting an internal combustion engine 5. The starter 1 is powered by a battery 2 and is switched on and off by a switch 3. The switch 3 is a button in conventional vehicles, which is installed in the ignition and is operated by turning the ignition key to ignition. In an alternative embodiment, the pushbutton 3 can activate a starter control 4 and be designed, for example, as a separate start button.

According to the invention, the starter control 4 has a current regulating device with which a starter current I can be regulated by a defined current value I _W. Thus, the starter 1 is no longer charged with the full charge of the battery 2, but the current I at the starter 1 is defined in a tolerance band to the current value I _W regulated. This has the advantage that the starter 1 is electrically and mechanically less stressed and the starter power increases, so that the standing with the starter 1 in mechanical operative connection internal combustion engine 5 can be turned on faster, such as Fig. 4 is described.

In order to increase the power at the starter 1, the current control device in the starter control 4 preferably comprises a DC / DC converter 6, which has a defined, controlled starter current I with a variable and higher Starter voltage U _s can provide. For this purpose, the DC / DC converter 6 is formed extended with a corresponding electronics.

The Fig. 2 shows a schematic circuit diagram of a vehicle electrical system according to the invention 7 with a vehicle electrical system module device 8. The electrical system module device 8 can also be referred to as a vehicle electrical system management module that supplies electrical energy consumers from energy storage and electrical energy from at least one electric generator in the energy storage again supplies. The electrical system 7 has a first sub-network 9 with a constant voltage of 12 to about 14 volts, which depends on the state of charge of a battery 2. In the electrical system 7, a plurality of consumers are arranged. In the first subnet 9, consumers 16 are connected in parallel with the battery 2, which are designed for a constant, low voltage between 12 and 14 volts. The electrical system 7 comprises a second subnetwork 10 which is provided for a variable voltage, greater than 14 volts. The voltage is generated by a multi-voltage generator 11, also called multi-voltage generator.

The onboard power supply module device 8 comprises a DC / DC converter 6, which converts the variable voltage of over 14 volts to the constant voltage of the first subnet 9. At the electrical system module device 8, the starter 1 is connected in a third subnetwork 12. This has the advantage that the starter 1 can be operated both with a constant voltage of up to 14 volts from the battery 2 from the first subnet 9, as well as the energy with a higher voltage from a capacitor, in particular a double-layer capacitor (DLC ) 13, which is connected in a fourth subnetwork 12 to the electrical system module device 8. The DC / DC converter 6 with an extended circuit has the additional advantageous function of how to Fig. 1 described, integrated starter control 4 represent.

The starter 1 is acted upon by the DC / DC converter 6 with a regulated starter current I to a defined current value I _W. The necessary Energy is primarily removed from the double-layer capacitor 13, which has a higher voltage than 14 volts. The double-layer capacitor 13 is charged by a corresponding control of the electrical system module device 8 directly from the multi-voltage generator 11 from the second subnet 10. If the double-layer capacitor 13 is charged, the battery 2 can then be charged by the multi-voltage generator 11, or possibly clocked in parallel, with the voltage of the multi-voltage generator 11 being converted into a constant voltage for the battery 2 by the DC / DC converter 6. The electrical system module device 8 thus assumes the control of the charge states of the battery 2 and the double-layer capacitor 13.

The electrical system module device 8 also has interfaces 15 in order to process signals in the form of information about temperatures and state variables of components, such as the crankshaft speed, and accordingly to take over the regulation of the charge states but also the control of the starter 1. The electrical system module device 8 is thus informed via the interface 15, which may be, for example, a bus interface such as LIN or CAN or the terminal 50, whether the starter 1 must perform a cold start, because the vehicle was parked for a long time or if a warm start is imminent because a start-stop operating strategy has been executed. Depending on the situation, the supply of the starter current I can be adjusted and different. In a memory stored characteristics support the control of the starter current I.

On-board network module device 8 also assumes the task of estimating the state of charge, the performance and the aging of the energy store, on the basis of measured variables of current I, voltage U on double-layer capacitor 13 and battery 2 and with the aid of a temperature measurement. Thus, the control of consumers and energy storage in the at least four different subnets can be efficiently implemented.

Due to the vehicle electrical system 7 according to the invention with the electrical system module device 8, there are many advantages. The life of the starter 1 is extended, since the starter 1 is applied during start-up of the starter 1 with a lower average starting current and lower pulse-shaped mechanical loads. Therefore, the starter 1 can be less expensive, simpler and possibly smaller. The third subnetwork 12 with the starter 1 is decoupled from the first subnetwork 9, on which the consumer 16 is arranged with a constant low voltage of the battery 2, by the installation and interposition of the DC / DC converter 6 in the onboard power supply module device 8. Thus, even with frequent start-stop operating strategies, the driver no longer recognizes voltage dips.

By using a multi-voltage generator 11 over a high variable voltage range, for example between 14 to 42 volts and more and at least one double-layer capacitor 13 or similar high-performance capacitors Rekuperationspotential over conventional wiring systems with a conventional generator in a significantly smaller and constant voltage range is significantly improved. The efficiency of the multi-voltage generator is significantly increased to over 80%.

Another advantage is that the battery 2 is reduced in the electrical system 7 by the controlled start of the starter 1 and the reduced starter currents I in size compared to conventional automotive electrical systems, since a battery 2 conventionally to the requirements of a start of the engine at low temperatures is designed and usually has to provide a correspondingly large starter current.

Thus, there are cost advantages through a reduction in size of the battery 2 and due to a lower wear, such as the brush or the commutator in the starter 1 due to lower starter currents I during startup. Another important advantage is that switching elements, as the DC / DC converter 6, which is integrated because of a multi-voltage generator 11 and associated double-layer capacitors 13 in the electrical system module device 8, shared and used appropriately extended to the starter current I in the starting process of the internal combustion engine 5 by a defined current value I _W regulate in which the starter current I is clocked. Thus, no additional separate power electronics for controlling the starter current I for the starter 1 is required. The onboard power supply module device 8 comprises the starter control 4 and additionally has important switching and charging functions.

In addition, the life of the battery 2 is significantly extended by supporting at least one double-layer capacitor 13, since the battery 2 is exposed to a much lower load.

The Fig. 3 shows the circuit diagram of a vehicle electrical system 7 in a second particular embodiment. In this embodiment, the battery 2 is in contrast to the first embodiment according to the Fig. 2 decoupled from the electrical system 7 with a voltage of about 12 volts to 14 volts through the electrical system module device 8. The battery 2 is thus located in the first subnet 9 and the consumers of the electrical system 16 with constant low voltage are arranged in a fifth subnet 17. This has the advantage that the fifth subnetwork 17 is decoupled from voltage drops in the first subnetwork 9, so that the comfort is improved and, if necessary, voltage dips very quickly, or not noticeable to the vehicle occupants, for example by the double-layer capacitor 13 in conjunction with the DC / DC converter 6 are compensated. The separation of the fifth subnetwork 17 with the consumers 16 with a constant vehicle electrical system voltage also has the advantage that the battery 2 can be charged or discharged more safely and statements about the battery 2 of the state of charge and the aging of high quality can be realized.

The Fig. 4 shows a time-current diagram of a starter 1 at start-up of the starter 1 to start an internal combustion engine 5. A dashed time-current characteristic H shows the course of the starter current in a conventional circuit of the starter 1 according to the Fig. 1 without a starter control built according to the invention 4. The starter current I increases in the first fractions of a second to 800 to 1000 amperes or even more, depending on the type of starter and type of internal combustion engine and then drops off very strong. There are in each case "mountain" peaks at the first, second and each further ignitable dead points 1. OT, 2. OT of each individual cylinder of the internal combustion engine until the internal combustion engine starts itself. The high starter current I during the starter start leads to wear and noise of the starter 1. The noise is caused by a high starting torque.

Due to the starter control 4, which is integrated in the electrical system module device 8, the starter current I by a defined current value I _W , for example, at 600 amps, on the first ignitable dead center, 1st TDC at least until shortly after the second upper ignitable dead center, 2nd OT, the internal combustion engine 5 regulated. This is represented by the time-current characteristic E with a solid solid line. The starter current I is clocked to control the current value of 600 amps. Thus, a current I is supplied to the starter 1 in a certain bandwidth around the current value I _W to be regulated. If the current I at the starter 1 exceeds a specific first value I _W1 , then the current supply is interrupted until the current I falls below a certain second value I _W2 , so that the starter 1 is again supplied with current I. The Fig. 3 shows the bandwidth and the variations of the current I by the current value I _W for the sake of simplicity only as a straight line E.

By changing the time-current characteristic curve from H to E, an increased power can be achieved from the starter 1, which is represented by the hatched area 18 between the characteristic curves E and H. The starter 1 thus has a higher torque and reaches the first and second and all other top dead centers 1 OT, 2 OT of the internal combustion engine 5 earlier. This results in a start time reduction t of the internal combustion engine 5, which in particular in a start-stop strategy is advantageous and is perceived by the driver as positive. In addition, emissions are reduced because a shorter start-up time avoids stopping and hindering other traffic. The time-current characteristic E can be realized on the basis of the DC / DC converter 6, which can supply the current I with a higher voltage in the starter 1.

In order to keep the energy loss as low as possible, the starter 1 is therefore preferably according to a first start method by means of a capacitor, in particular the double-layer capacitor 13, in the first start phase and a regulated starter current I and a higher voltage, which is above 14 volts, applied and In a second phase, should the energy from the double-layer capacitor 13 for the complete start of the internal combustion engine is not sufficient, fed by the battery 2.

According to a second operating mode, according to the characteristic curve E, the energy is supplied exclusively from the battery 2 to the starter 1 when, for example, the vehicle has been switched off for a longer time and the double-layer capacitor 13 has not yet been charged.

According to a further, third starting method, the double-layer capacitor 13 is charged shortly before the start of the internal combustion engine 5 by means of the electrical system module device 8 of the battery 2, so that the starter 1 is in turn supplied with the energy of the double-layer capacitor 13 in the first start phase. The electrical system module device 8 thus regulates with integrated starter control 4, the power supply from two different technically constructed energy storage, the battery 2 and the double-layer capacitor 13 to start the starter 1. Due to the dual function of the DC / DC converter 6 and the splitting of the electrical system 7 in several, at least three subnetworks, electrical components are used efficiently, in particular the electric machine 1 as a starter with extended life.

All figures show only schematic not to scale representations. Incidentally, reference is made in particular to the drawings for the invention as essential.

Claims (11)

Method for starting an internal combustion engine (5) of a vehicle by means of a starter (1) and a starter control (4) connected thereto, characterized in that a starter current (I) is controlled in the starting process by the starter control (4) comprising electronic components becomes. A method according to claim 1, characterized in that the starter current (I) by the starter control (4) of the starter (1) is clocked, so that the starter (1) by a defined current value (I _W ) is operated. A method according to claim 1 or 2, characterized in that the starter (1) is acted upon by the starter control (4) with a variably adjustable starter voltage (U _S ) defined. Method according to one of Claims 1 to 3, characterized in that the power output for starting the starter (1) is regulated by means of the starter control (4) from at least two energy stores, in particular technically differently constructed energy stores, particularly preferably a battery (2) and / or or at least one capacitor. Method according to one of Claims 1 to 4, characterized in that information is received and processed by the starter control (4) at interfaces (15) so that at least the starter current (I _S ) and / or the starter voltage (U _S ) are dependent the information is regulated. A computer program product loadable in a program memory with program instructions for carrying out all the steps of a method according to at least one of claims 1 to 5 when the program is executed in a starter controller (4). Starter control (4) with control electronics, for a starter (1) for starting an internal combustion engine (5) in a vehicle, wherein in the starter control in particular a method according to one of claims 1 to 5, preferably carried out by means of a computer program product according to claim 6, characterized in that the starter control (4) comprises a current control device with which the starter current (I) can be regulated by a defined current value (I _W ). Starter control (4) according to claim 7, characterized in that the current control device comprises a DC / DC converter (6). Vehicle electrical system (7) for a motor vehicle with a first constant low voltage sub-network (9) for a consumer and / or energy storage and a second high-voltage sub-network (10), for at least one multi-voltage generator (11) and an energy store for high voltage and with a charging control, characterized in that at least one third, independent, variable sub-network (12) is designed to control at least one consumer (16) and / or energy store. Vehicle electrical system (7) according to claim 9, characterized in that at least a fourth, independent subnetwork (14) with at least one consumer (16) and / or energy storage is formed. Vehicle electrical system module device (8) for a motor vehicle, comprising a DC / DC converter (6), a controller for a multi-voltage generator (11) and having at least one electrical energy store for a high voltage and having an electrical energy store with a low voltage, characterized in that the DC / DC converter (6) as part of a starter control (49, in particular according to claim 7 or 8 is formed by at least two different subnets, a first subnetwork (9) for the multi-voltage generator (11) with a multiple voltage and at least one second Subnetwork (10) for a starter (1), independently of each other.

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