EP1046811B1 - Electric drive apparatus for internal combustion engines in vehicles - Google Patents

Description

The invention relates to an electric drive arrangement for Internal combustion engines in motor vehicles, with one to the internal combustion engine detachable electric starter and an in Drive connection with the internal combustion engine standing electric Generator according to the preamble of claim 1, and is known from DE-A-197 05 610.

The starting of internal combustion engines in road vehicles happens for decades by means of an electric starter, which only during the starting phase on its starter pinion and the sprocket on the flywheel with the crankshaft of the internal combustion engine mechanically connected. All starter motors have today the torque characteristic of a main closure machine, which essentially by a with increasing speed continuously decaying to zero output torque characterized is, starting with the maximum possible torque at standstill. This characteristic leads to the torque balance during the starting process between starter torque and drag torque the internal combustion engine at crankshaft speeds between 80 and 200 U / min, which according to previous requirements for Start sufficient. To minimize this starter motors, easy and cheap to implement, according to previous requirements DC machines in series construction or with permanent magnetic excitation and the largest possible mechanical Translation used to crankshaft. The overall translation from countershaft in starter as well as translation from Starter pinion to the crankshaft is about 60: 1. This high translation requires an engagement device which only on actuation of the starter a driving connection to Crankshaft produces and thus the starter motor for extreme speeds protects.

Future emissions regulations can expect that described Design of a starting system is no longer sufficient. The default the previous minimum starting speeds on the crankshaft cause high pollutant emissions in today's starting process, and it is known that an increase in the starting speed Values in the range of the idle speed of the internal combustion engine has considerable potential for improvement on this point.

Another disadvantage of today's launch facilities is that due to the high gear ratio of the starter to the crankshaft and the necessary engagement and disengagement of the starter pinion Occasions take a relatively long time and are relatively loud. This is less and less accepted by customers, especially future ones Operating concepts of vehicles for compliance with fleet consumption targets make much more starting necessary become. This results in problems with the life of today Launch facilities.

From EP 0 793 013 A1 it is known to start the process a belt-driven three-phase generator (alternator) instead with the help of a conventional starter, wherein a semiconductor circuit arrangement for the motor Operation as inverter and for generator operation is switchable as a rectifier. Problems arise at very low temperatures, as the maximum torque of such Arrangement is no longer sufficient to start the engine safely. The use is therefore at best on internal combustion engines limited with small displacement. Would you be an interpretation for perform large internal combustion engines, even at low Temperatures are working safely, so this would be unacceptable lead large, heavy and expensive generators.

According to EP 0 406 182 B1 an attempt is made to solve this problem to solve that by means of a boost circuit for starting a higher voltage can be generated, which in the motor operated Generator briefly causes higher currents and thus the moment increases. However, this solution has the disadvantage that the belt drive loses grip at low temperatures and slipping. In addition, the charging time of the Startup memory, whereby shortly one after another take-offs are not possible. Furthermore, the life of a Such arrangement required for the many starts required inadequate for future concepts.

In one of DE-A-197 05 610 which is considered to be the closest prior art, known drive arrangement The drive torques overlap in combined operation of generator and starter effective as the active generator with its torque just where the starter to let up. The crankshaft of the internal combustion engine This is far superior to what can be achieved with a starter today Speed also accelerated very quickly, so that even at low temperatures ensures a quick and safe start is. When cold start, therefore, a division of responsibilities between conventional starter (overcoming the breakaway torque) and the generator (increasing the cranking torque in Range of higher crankshaft speeds).

The object of the present invention is to provide an electrical To provide drive arrangement for internal combustion engines, through the inexpensive way a faster and more cost effective comfortable starting process possible with improved efficiency is.

This object is achieved by an electric drive arrangement solved with the features of claim 1.

By the drive arrangement according to the invention, the semiconductor circuit advantageously for motor operation the generator designed as an AC or alternator as inverter and for generator operation switchable as a rectifier, so that a single semiconductor circuit can be used for both modes with corresponding efficiency improvement by active rectification in generator mode. The setting of a defined Angular position of the crankshaft of the internal combustion engine when parking the same with the help of the motor-operated generator also contributes to the improvement of the efficiency, wherein if the combination of these measures still has effects increase. For this purpose, the generator is for example as a fuller Four-quadrant positioning drive trained. Of the The next start procedure can thus be from a defined starting position take place, whereby the starting process considerably accelerates and significantly reduces pollutant emissions becomes. In addition, one of the usual sensors, Either the OT sensor or the camshaft sensor saved become.

By the measures listed in the dependent claims are advantageous developments and improvements in the claim 1 specified drive arrangement possible.

The decision whether the starting process alone by means of the motor operated generator or by means of this generator in Combination with the starter should be made, meets the electronic Control device in an optimal manner depending on the Engine oil temperature and / or the outside temperature and / or the shutdown time the internal combustion engine. To start the internal combustion engine at low temperature are the generator and the starter simultaneously or successively temporally overlapping or not overlapping switched on. These variants can, for example alternatively as a function of the respective start parameters to get voted.

Particularly favorable for consumption and low pollutant emissions are means for activating ignition and / or Injection during the starting process of the internal combustion engine only at Speeds near the starting speed, for example at 80% of Starting speed.

Advantageously, the electronic control device also to support deceleration processes of the internal combustion engine by switching on the generator operated Generator and / or to support acceleration the internal combustion engine by turning on the motor operated generator can be used. For example, can the motor operation of the generator with the internal combustion engine running be used for driving dynamics support, ie as Supportive intervention of the active generator during all startup procedures the internal combustion engine. On the other hand, too Rotation energy of the internal combustion engine operated as a generator Generator are recovered, especially in the thrust and Braking operation, so that the generator additionally the desired Delay process supported. This is done appropriately depending on the speed of the internal combustion engine.

The active generator can also advantageously with gear changes in manual transmissions with to synchronize engine and Transmission speeds are used. The energy, which implemented in the synchronizing rings of the transmission for speed matching must be recovered by the generator with faster gear changes, the synonymous with appropriate interpretation even synchronizer rings and a Clutch can make dispensable. With pending gear change the engine is controlled with the support of the generator so that no torque is transmitted in the drive train. Then you can relax take out the respective gear. Thereafter, a renewed Speed adjustment using an electronic accelerator pedal or with the help of an electronic throttle and electronic Support. When the engine speed to the new transmission speed synchronized, the new gear can be without Engage shift shock.

Furthermore, in an advantageous manner by switching of the generator-operated generator or the motor-operated generator Generator too large belt slip when (slipping) the drive belt between the engine and Generator can be prevented. Additional moments on the belt drive can be connected and disconnected belt-friendly or be compensated, so that the life of the drive belt increased and defects are largely prevented.

Figur 1

eine schematische Darstellung einer mit einem Anlasser und einem elektrischen Generator versehenen Brennkraftmaschine und

Figur 2

ein Diagramm zur Erläuterung der Wirkungsweise.

An embodiment of the invention is illustrated in the drawing and explained in more detail in the following description. Show it:

FIG. 1

a schematic representation of a provided with a starter and an electric generator internal combustion engine and

FIG. 2

a diagram to explain the mode of action.

In the embodiment shown in Figure 1 is a schematically illustrated internal combustion engine 10 of the rest not shown motor vehicle with a starter 11 and an electric generator 12 (alternator) provided, wherein the electric generator 12 in a manner not shown coupled via a belt drive with the internal combustion engine 10 is.

The starter 11 is direct and the electric generator 12 via a semiconductor circuit arrangement 13 with a supply battery 14 connected.

An electronic control device 15 controls the starter 11 and the semiconductor circuit arrangement 13 as a function of Sensor signals and tempering control signals, the control device Receives 15 by means of a starter switch 16 in the ignition integrated and / or designed as a separate starter switch can be. In the embodiment, the control device 15 sensor signals of an outside temperature sensor 17, an oil temperature sensor 18 and an intake manifold pressure sensor 19 fed. In addition, however, the controller 15 may For example, even sensor signals are supplied, the from the battery state of charge, the battery voltage, the battery and vehicle electrical system current, from the engine speed, from pedal positions or parameter switches are dependent.

The semiconductor circuitry 13 receives from the controller 15 depending on the operating state control signals for a motor (active) or generator operation of the generator 12. For the generator operation, the semiconductor switch assembly 13 connected as a rectifier or rectifier bridge, while they are for motor operation as an inverter for the trained as an AC or alternator Generator 12 is switched.

Activated in response to a starting signal through the starter switch 16 the electronic control device 15, the starter 11 and Switches the semiconductor circuit arrangement 13 as an inverter. This causes the starter 11 and the generator 12 together the starting process of the internal combustion engine 10. In the figure 2 are the torques and mechanical performance of starters 11 and generator 12 shown on the crankshaft, wherein the solid lines the torques and the dashed Lines the powers depending on the crankshaft speed represent. This illustration shows that the first high torque of the starter quickly and steadily increasing Speed drops to vanishingly low values and the initially rising performance also below 300 RPM drops to a value of substantially zero. In contrast For this purpose, the torque of the generator 12 is constant and the power increases essentially linearly. The diagram shows thus that the active generator with its torque straight where the starter's begins to wear off. The superposition of both drive torques is on the crankshaft effective and accelerates these far beyond today A starter achievable speed addition.

This combined operation is especially at cold start and low outside temperatures required, as the conventional Starter 11 has an initially very high drive torque, which is effective even at low temperatures.

With a warm internal combustion engine 10 or high outside temperatures if only the electric generator 12 is required for the starting process, so that only the semiconductor circuit arrangement 13 is switched accordingly as an inverter.

These two different start procedures, so the cold start and the warm start are in the controller 15 as an algorithm deposited as a function of corresponding sensor signals. For example, the cold start can be defined be that the engine oil temperature and the outside temperature below a predetermined value is and / or that the shutdown time since the last operation of the internal combustion engine greater than one is predeterminable time interval. Accordingly reversed is the Warm start defined, thus at engine oil temperatures and outside temperatures above definable values and / or during shutdown times is less than a predetermined time interval. These sensor sizes can also interact in a specific way stand.

For the cold start can have two different starting procedures be realized, wherein at a startup of the motor-operated generator parallel to the starter 11 works. The starter is then deactivated at a certain speed, and the motor-driven generator accelerates the crankshaft continues to the starting speed.

In the second variant, the starter 11 is first turned on and only after reaching a certain speed this is deactivated and the motor-operated generator activated. To reduce consumption and reduce harmful Exhaust gases occur until reaching a speed value, for example, 80% of the starting speed corresponds, no injection and no ignition, so that the internal combustion engine 10th is started at this time, which then very fast he follows. This is done by means of an electronic, not shown Motor control, which is in operative connection with the electronic Control device 15 can stand. This delayed Insertion of ignition and injection takes place accordingly even at a boot process alone by the generator 12th

Usual starters 11 have a total translation of approx. 60: 1, resulting from the translation of starter pinion to the crankshaft and from the submission translation. In the inventive Arrangement can significantly reduce this translation be, for example, the counterclaim can be omitted, so that results in a total translation of 15: 1.

Regardless of the starting process, the electronic control device 15 even while the internal combustion engine 10 the Control generator 12, for example, for driving dynamics support. For example, in all acceleration operations of Internal combustion engine 10, the motor-driven generator 12th support these acceleration processes. On the other hand can he also support deceleration processes in generator mode that is, in overrun mode and braking mode, it becomes regenerative operated so that not only dependent on the driving situation electrical energy is recovered, but also the deceleration process is actively supported.

Furthermore, the electronic control device 15 switching operations at gear changes of the transmission of the internal combustion engine 10 actively assist and synchronize engine and Transmission speeds are used. To increase the speed is while the motor-operated generator 12 and speed reduction the generator-operated generator 12 is used become. This leads to faster gear changes, causing less Even a clutch can be omitted.

Furthermore, the electronic control device 15 for preventing a belt slippage of the drive belt for the generator 12 serve. A measuring device, not shown for Recognition of the belt slip gives its measuring signals to the electronic Control device 15 further, by means of the active Generator 12 the belt slip causing additional moments on the belt drive belt-friendly on and disengages or compensated. This measuring device for detecting the belt slippage can also be part of the electronic control device 15 be where speeds of generator 12 and internal combustion engine 10 compared with each other. For belt slip detection can, for example, at the leading strand and return strand of the Drive belt depending a measuring roller to be articulated resiliently, the the taking place due to different moments stretching the Capture drive belt. The detection of belt slippage allows a preventive belt diagnosis, and a looming belt problem can be communicated to the driver of a motor vehicle early be, for example, by a visual and / or acoustic Warning device or a display.

The electronic control device 15 can also be used for positioning the crankshaft are used. When parking The internal combustion engine is the crankshaft by the motor operated generator 12 a favorable well-defined starting position impressed. The generator is for this purpose, for example as fully developed four-quadrant positioning drive. The next startup process of the internal combustion engine can thereby take place from a defined initial position, whereby the Startup process is significantly accelerated.

The arrangement according to the invention is also suitable for control or influencing the outlet of the internal combustion engine 10. It poses a problem that often undefined amounts of fuel after stopping the engine 10 in the intake system and remain in the cylinders. The volatile parts of the fuel evaporate, while this is difficult flammable fractions is not the case. They deteriorate the exhaust when re-starting the engine. this will avoided in one embodiment of the invention in that at Turn off the engine 10, the fuel supply or Fuel injection is switched off. The internal combustion engine 10 is then by the generator 12 in the engine operation held in rotation for a certain time, causing the internal combustion engine rinsed and fuel residues, which are also in the catalyst can be disposed of harmlessly. At a restart the engine, the engine control unit or the control device 15 of an "empty" internal combustion engine go out, which facilitates a defined start.

After rinsing and disposal of the fuel residues, the Internal combustion engine 10 defined by means of the generator 12 at regenerative braking to a standstill, because a long follow-up phase is undesirable.

Another application of the drive arrangement according to the invention is to start-stop operations of the internal combustion engine 10, for example, to improve traffic lights. The chances for a Realization improve especially when the start of the Internal combustion engine or the motor vehicle in each case without delay he follows. Even the slightest delay is on above all subjectively extremely disturbing noticeable. With help the electronic control device 15 is in communication possible with the generator 12, without disengagement of the internal combustion engine to stop the vehicle. Possibly otherwise available Torque shocks can be compensated comfortably by the generator become. The start is then again without Actuation of a clutch by "electric" start, what entirely without delay is possible. This can of course even when disengaged internal combustion engine done. The purely electric starting takes place in motor operation the generator 12 in eventual support by the Starter 11, especially in cold engine or very low temperatures. The coupling or starting the Internal combustion engine 10 can then be delayed in time, in particular also pulse-shaped. Since when starting the Internal combustion engine then the vehicle is already in motion, will be the kinetic energy of the entire vehicle and not only individual drive train parts for starting the internal combustion engine co-used, so that a safe start is guaranteed.

Such a start-stop system preferably works in conjunction with a road condition detection system, such as an electronic Stabilization system or traction control system.

Claims (14)

1. Electric drive assembly for internal combustion engines in motor vehicles, with an electric starter (11) capable of being coupled to the internal combustion engine (10) and an electric generator (12) in driving connection with the internal combustion engine (10), connected to a supply battery (14) via a semiconductor circuit arrangement (13), the generator (12) being optionally operated in generator or in motor mode by means of the semiconductor circuit arrangement (13), and with an electronic control unit (15) for the control of the starting process of the internal combustion engine (10), which starting process is effected in dependence on the signal of at least one temperature sensor (17, 18) either solely by means of the generator (12) in motor mode or in combination with the starter (11), characterised in that the semiconductor circuit arrangement (13) is switched as an inverter circuit for the motor mode of the generator (12), which is designed as an ac generator or alternator, and as a rectifier circuit for its generator mode, and in that the electronic control unit (15) is designed to adjust the crankshaft of the internal combustion engine (10) to a defined angular position when stopping it with the aid of the generator (12) operating in motor mode.
2. Drive assembly according to claim 1, characterised in that the starting process can be controlled in dependence on engine oil temperature and/or ambient temperature and/or the stopping time of the internal combustion engine (10).
3. Drive assembly according to claim 1 or 2, characterised in that the electronic control unit (15) is designed to start the internal combustion engine (10) by means of the generator (12) and the starter (11) at low temperatures and by means of the generator (12) on its own at higher temperatures.
4. Drive assembly according to claim 3, characterised in that the generator (12) and the starter (11) can be switched on either simultaneously or in sequence with or without overlap when starting the internal combustion engine (10) at low temperatures, i.e. during a cold start.
5. Drive assembly according to any of the preceding claims, characterised in that means are provided for activating ignition and/or injection during the starting process of the internal combustion engine only at speeds approaching its starting speed.
6. Drive assembly according to any of the preceding claims, characterised in that the electronic control unit (15) is designed to support deceleration processes of the internal combustion engine (10) by activating the generator (12) in generator mode and/or to support acceleration processes of the internal combustion engine (10) by activating the generator (12) in motor mode.
7. Drive assembly according to claim 6, characterised in that the activation of the generator (12) in generator mode is effected in dependence on the speed of the internal combustion engine, in particular above a preset cutting-in speed.
8. Drive assembly according to claim 6 or 7, characterised in that the generator (12) is activated in generator and/or motor mode to synchronise engine and transmission speeds during a gear change.
9. Drive assembly according to any of claims 6 to 8, characterised in that the generator (12) is activated in generator and/or motor mode to compensate for different moments acting on the belt drive of the generator (12).
10. Drive assembly according to any of the preceding claims, characterised in that the electronic control unit (15) or other means for activating the generator (12) in motor mode after the internal combustion engine (10) has been stopped and for disconnecting the fuel supply are designed to keep the internal combustion engine (10) rotating for an after-running phase, until any fuel residues in the internal combustion engine and/or in a catalyst are substantially removed.
11. Drive assembly according to claim 10, characterised in that means are provided for switching the generator (12) from motor to generator mode after the after-running phase.
12. Drive assembly according to any of the preceding claims, characterised in that the electronic control unit (15) is designed to control the starting process of the internal combustion engine (10) while essentially starting the motor vehicle simultaneously at least by means of the generator (12) operating in motor mode.
13. Drive assembly according to claim 12, characterised in that the internal combustion engine (10) is connected with a time delay, in particular in a pulsed manner, when the motor vehicle is started purely electronically at least by means of the generator (12) operating in motor mode.
14. Drive assembly according to any of the preceding claims, characterised in that the electronic control unit (15) is designed to control the stopping process of the motor vehicle by means of the generator (12) without disconnecting the internal combustion engine (10).

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