EP1046811A1 - Electric drive apparatus for internal combustion engines in vehicles - Google Patents

Abstract

The drive has an electric starter (11) for coupling to the engine (10) and an electrical generator (12) with a drive couplin the engine and connected to a power supply battery (14) via a semiconducting circuit (13) enabling the generator to be operated generator or as a motor. An electronic controller (15) controls the starting process using the generator operated as a motor wit without the starter depending on the signal from at least one temp. sensor (17,18).

Description

The invention relates to an electric drive arrangement for Internal combustion engines in motor vehicles, with one to the internal combustion engine connectable electric starter and one in Drive connection with the internal combustion engine standing electrical Generator.

Internal combustion engines are started in road vehicles for decades using an electric starter, which only during the start phase via its starter pinion and the ring gear on the flywheel with the crankshaft of the internal combustion engine is mechanically connected. All starter motors have the torque characteristics of a main closing machine today, which is essentially due to an increasing speed Delivery torque continuously falling to zero is, starting with the maximum possible torque at standstill. This characteristic leads to a 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 current requirements for Start is sufficient. To keep these starter motors as small as possible, easy and cheap to implement, according to previous requirements DC machines in series connection or with permanent magnetic excitation and the greatest possible mechanical Ratio to crankshaft used. The overall translation from gearbox in the starter as well as translation from Starter pinion to the crankshaft is approx. 60: 1. This high Translation requires an engagement device, which a driving connection to the Manufactures crankshaft and thus the starter motor for extreme speeds protects.

Future emission regulations can be expected that the 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 that due to the high ratio of the starter to the crankshaft and the necessary engagement and disengagement of the starter pinion Starting processes take a relatively long time and are relatively loud. This is less and less accepted by customers, especially in the future Operating concepts of the vehicles to meet fleet consumption targets require significantly more starting processes become. This poses problems with the lifespan of today Starting facilities.

From EP 0 793 013 A1 it is known to carry out the starting process a belt-driven generator (alternator) instead of with Using a conventional starter. Problems arise at very low temperatures because the maximum torque such an arrangement is no longer sufficient Then start the engine safely. The use is therefore at best limited to small displacement engines. Would to carry out a design for large internal combustion engines, that works safely even at low temperatures this would make unacceptable large, heavy and expensive generators to lead.

This problem is attempted from EP 0 406 182 B1 to solve that by means of a boost circuit for starting a higher voltage can be generated, which in the motorized Generator temporarily causes higher currents and thus the moment increases. However, this solution has the disadvantage that the belt drive loses grip at low temperatures and tends to slip. The charging time of the Start memory, which means that the starting processes take place in quick succession are not possible. Furthermore, the lifespan is one such an arrangement for the many start-up operations inadequate future concepts.

It is therefore an object of the present invention to an electric drive arrangement for internal combustion engines create a faster by cost-effectively and more comfortable starting process is also possible at low temperatures.

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

The drive arrangement according to the invention has in particular the Advantage that the drive torques in combined operation of generator and starter effectively overlay, since the active Generator with its torque just where the starter starts to wear off. The crankshaft of the internal combustion engine it goes far beyond those with one today Starter achievable speed accelerated very quickly, so that even at low temperatures a faster and safer Start is guaranteed. The task is therefore divided on a cold start between conventional starters (overcoming the Breakaway torque) and the generator (increase of the starting torque) in the area of higher crankshaft speeds). An oversize of the generator including power electronics and a unwanted intervention in the drive train can be avoided which today is optimized in terms of cost and size Starter can be used almost unchanged. The Solution according to the invention thus represents a cost optimum in Solution to the task at hand. At higher outside temperatures and / or warm engine, the starting process can only be done with the Generator take place, which then makes it particularly quiet and comfortable start is made possible. Depending on the signal at least one temperature sensor decides the electronic one Control device in an advantageous manner as the Start process should be carried out.

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

The semiconductor circuit is advantageous for the motor Operation of the as an AC or three-phase generator trained generator as an inverter and for the generator Operation as a rectifier switchable, so that a single Semiconductor circuit used for both modes can be achieved with a corresponding improvement in efficiency active rectification in generator mode.

The decision as to whether the starting process is solely by means of the motor operated generator or by means of this generator in In combination with the starter, the electronic one 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 overlapping at the same time or in succession or cannot be switched on overlapping. These variants can, for example alternatively depending on the respective start parameter to get voted.

The electronic control device can also be advantageous Way to set a defined angular position of the crankshaft the engine when turning it off with the help of the motor-driven generator. For this is the generator, for example, as a full four-quadrant positioning drive educated. The next startup can be done from a defined starting position, which significantly accelerates the starting process and pollutant emissions is significantly reduced. In addition, one the previously common sensors, either the OT sensor or the camshaft sensor can be saved. Very cheap are resources for consumption and low pollutant emissions to activate ignition and / or injection at Starting process of the internal combustion engine only at speeds close to the starting speed, for example at 80% of the starting speed.

The electronic control device can advantageously also to support deceleration processes of the internal combustion engine by switching on the generator Generators and / or to support acceleration processes the internal combustion engine by switching on the motor operated generator are used. For example the motor operation of the generator with the internal combustion engine running be used to support driving dynamics, i.e. as supportive intervention of the active generator in all Start-up processes of the internal combustion engine. On the other hand, can also rotational energy of the internal combustion engine with a generator operated generator are recovered, especially in Thrust and brake operation, so that the generator additionally supports the desired deceleration process. this happens expediently depending on the speed of the internal combustion engine.

The active generator can also be used advantageously when changing gears in manual transmissions with for the synchronization of engine and Gear speeds are used. The energy which implemented in the synchronizer rings of the transmission for speed adjustment can be recovered by the generator with faster gear changes, which, with the appropriate design, even synchronizer rings and one Can make the clutch unnecessary. With a pending gear change the engine is controlled with the help of the generator that no moment is transmitted in the drive train. Then you can remove the respective gear. Then there is another 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 is synchronized, the new gear can be without Insert shift shock.

Furthermore, it can also be advantageously switched on of the generator operated generator or the motor operated Generator too big belt slip when (slipping) of the drive belt between the engine and Generator can be prevented. Additional moments on the belt drive can be coupled in and out in a belt-friendly manner 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 shown in the drawing and explained in more detail in the following description. Show it:

Figure 1

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

Figure 2

a diagram for explaining the mode of action.

In the embodiment shown in Figure 1 is one schematically illustrated internal combustion engine 10 one in the rest Motor vehicle, not shown, with a starter 11 and an electric generator 12 (alternator), wherein the electrical generator 12 in a manner not shown coupled to internal combustion engine 10 via a belt drive 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 starter control signals that the control device 15 by means of a starter switch 16, which is in the ignition lock integrated and / or designed as a separate starter switch can be. In the exemplary 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, the control device 15 can, however For example, sensor signals can also be supplied on the battery state of charge, on the battery voltage, on the battery and vehicle electrical system current, on the engine speed, on pedal positions or parameter switches are dependent.

The semiconductor circuit arrangement 13 receives from the control device 15 depending on the operating state control signals for a motor (active) or generator operation of the generator 12. The semiconductor switch arrangement is used for generator operation 13 switched as a rectifier or rectifier bridge, while for motor operation as an inverter for those trained as AC or three-phase generators Generator 12 is switched.

Activated by the starter switch 16 in response to a start signal the electronic control device 15 the starter 11 and switches the semiconductor circuit arrangement 13 as an inverter. As a result, the starter 11 and the generator 12 work together the starting process of the internal combustion engine 10. In the figure 2 are the torques and mechanical power of the starter 11 and generator 12 shown on the crankshaft, wherein the solid lines the torques and the dashed lines Lines the outputs depending on the crankshaft speed represent. This illustration shows that initially high starter torque quickly and steadily with increasing Speed drops to vanishingly low values and the initially increasing output also below 300 RPM drops to a value of essentially zero. In contrast the torque of the generator 12 is constant and the performance increases essentially linearly. The diagram thus shows that the active generator with its torque straight starts where the starter's starts to wear off. The superposition of both drive torques is on the crankshaft effective and speeds it up far more than today speed achievable by a starter.

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

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

These two different starting processes, i.e. the cold start and the warm start are in the control device 15 as an algorithm depending on the corresponding sensor signals. For example, this defines the cold start be that the engine oil temperature and the outside temperature are below a predeterminable value and / or that the shutdown time larger than one since the last operation of the internal combustion engine predeterminable time interval is. The reverse is accordingly Warm start defined, which means at engine oil temperatures and outside temperatures above definable values and / or in the case of downtime is less than a predeterminable time interval. These sensor sizes can also function in relation to one another stand.

Two different starting methods can be used for the cold start can be realized, with the one starting procedure the motor-operated generator works in parallel to the starter 11. 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, starter 11 is first switched on and only after reaching a certain speed this deactivates and the motor-driven generator is activated. To reduce consumption and reduce harmful Exhaust gases occur until a speed value is reached, which corresponds to 80% of the starting speed, for example, no injection and no ignition, so that the internal combustion engine 10 only starts at this point, which then very quickly 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 Ignition and injection start accordingly even when starting alone by the generator 12.

Usual starters 11 have a total gear ratio of approx. 60: 1 resulting from the translation of starter pinion to crankshaft and results from the transmission ratio. In the case of the invention Arrangement can significantly reduce this translation can be omitted, for example that there is a total translation of 15: 1.

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

Furthermore, the electronic control device 15 switching operations when changing the gear of the internal combustion engine 10 actively support and to synchronize engine and Gear speeds are used. To increase the speed the motor-operated generator 12 and for speed reduction the generator 12 operated as a generator become. This leads to faster gear changes, which results in under Circumstances even a clutch can be omitted.

Furthermore, the electronic control device 15 for prevention a belt slip of the drive belt for the generator 12 serve. A measuring device, not shown Belt slip detection transmits its measurement signals to the electronic Control device 15 further, by means of the active Generator 12 additional moments causing the belt slip Belt-friendly coupling and uncoupling on the belt drive or compensated. This measuring device for the detection of belt slip can also be part of the electronic control device 15 where the speeds of generator 12 and internal combustion engine 10 are compared with each other. For belt slip detection can, for example, on the forward run and return run of the Drive belt each have a measuring roller articulated, the the expansion of the Detect drive belt. The detection of the belt slip allows preventive belt diagnosis and an impending belt problem can inform the driver of a motor vehicle in good time be, for example by an optical 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 engine becomes the crankshaft by the motor operated generator 12 a favorable well-defined starting position imprinted. The generator is for this purpose, for example fully-fledged four-quadrant positioning drive. The next starting process of the internal combustion engine can thereby take place from a defined starting position, whereby the Starting process is accelerated considerably.

The arrangement according to the invention is also suitable for control or influencing the outlet of the internal combustion engine 10. Es is a problem that often undefined amounts of fuel after switching off the internal combustion engine 10 in the intake system and remain in the cylinders. The volatile parts of the fuel evaporate while doing so at the heavy flammable proportions is not the case. You worsen the exhaust gas when the internal combustion engine is started again. this will circumvented in one embodiment of the invention in that when Switching off the internal combustion engine 10, the fuel supply or Fuel injection is switched off. The internal combustion engine 10 is then in generator mode by the generator 12 kept in rotation for a period of time, causing the internal combustion engine flushed and fuel residues that are also in the catalytic converter can be disposed of. At a The engine control unit can restart the internal combustion engine or the control device 15 of an "empty" internal combustion engine run out, which facilitates a defined start.

After flushing and disposing of the fuel residues, the Internal combustion engine 10 is defined with the aid of generator 12 regenerative operation are braked to a standstill, because a long post-run phase is undesirable.

Another application of the drive arrangement according to the invention consists of start-stop processes of the internal combustion engine 10, to improve at traffic lights, for example. The chances for one 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 delays occur subjectively extremely disturbing. With help it is connected to the electronic control device 15 possible with the generator 12 without disengaging the internal combustion engine to stop the vehicle. Possibly otherwise existing Torque surges can be easily compensated for by the generator become. The start then also takes place without Actuation of a clutch by "electrical" starting what is possible without any delay. This can be taken for granted also take place with the internal combustion engine disengaged. The purely electrical start-up takes place in motor operation of the generator 12 with any support from the Starter 11, especially when the engine is cold or very low temperatures. Coupling or starting the Internal combustion engine 10 can then be delayed somewhat, in particular also take place in pulses. Because when starting the Internal combustion engine the vehicle is already in motion, becomes the kinetic energy of the entire vehicle and not only individual drive train parts for starting the internal combustion engine shared, 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 one Stabilization system or anti-slip control system.

Claims (16)

Electrical drive arrangement for internal combustion engines in Motor vehicles with a coupling to the internal combustion engine (10) electric starter (11) and one in drive connection with the internal combustion engine (10) standing electrical Generator (12), which has a semiconductor circuit arrangement (13) is connected to a supply battery (14), wherein the generator (12) by means of the semiconductor circuit arrangement (13) can be operated either as a generator or as a motor and with an electronic control device (15) for Control of the starting process of the internal combustion engine (10), which in Dependency of the signal of at least one temperature sensor (17, 18) with the help of the motor-driven generator (12) alone or together with the starter (11). Drive arrangement according to claim 1, characterized in that the semiconductor circuit arrangement (13) for the motor Operation of the as an AC or three-phase generator trained generator (12) as an inverter and for generator operation can be switched as a rectifier. Drive arrangement according to claim 1 or 2, characterized in that the starting process depends on the engine oil temperature and / or the outside temperature and / or the shutdown time the internal combustion engine (10) is controllable. Drive arrangement according to one of the preceding claims, characterized in that the electronic control device (15) to start the internal combustion engine (10) at low Temperatures using the generator (12) and the starter (11) and at higher temperatures using the generator (12) is trained alone. Drive arrangement according to claim 4, characterized in that to start the internal combustion engine (10) at lower Temperatures (cold start) of the generator (12) and the starter (11) overlapping at the same time or successively or cannot be switched overlapping. Drive arrangement according to one of the preceding claims, characterized in that the electronic control device (15) for setting a defined angular position of the Crankshaft of the internal combustion engine (10) when turning it off with the help of the motor-driven generator (12) is. Drive arrangement according to one of the preceding claims, characterized in that means for activating ignition and / or injection during the starting process of the internal combustion engine intended only at speeds close to the starting speed are. Drive arrangement according to one of the preceding claims, characterized in that the electronic control device (15) to support delay operations of the Internal combustion engine (10) by switching on the generator operated Generator (12) and / or to support acceleration processes the internal combustion engine (10) by switching on of the motor-driven generator (12) is. Drive arrangement according to claim 8, characterized in that switching on the generator operated generator (12) depending on the speed of the internal combustion engine is provided, in particular above a predetermined switch-on speed. Drive arrangement according to claim 8 or 9, characterized in that that switching on the generator operated and / or the motor-driven generator (12) for synchronization of engine and transmission speed provided for gear changes is. Drive arrangement according to one of claims 8 to 10, characterized characterized in that the switching on of the generator operated and / or the motor-driven generator for Compensation of different moments on the belt drive of the generator (12) is provided. Drive arrangement according to one of the preceding claims, characterized in that the electronic control device (15) or other means to turn on the motorized Generator (12) after switching off the internal combustion engine (10) and fuel cut are designed to the internal combustion engine (10) during a post-operation phase to keep rotating until in the internal combustion engine (10) and / or fuel residues still contained in a catalytic converter are essentially removed. Drive arrangement according to claim 12, characterized in that means for switching the generator (12) after the Post-operation phase from motor operation to generator operation Operation are provided. Drive device according to one of the preceding claims, characterized in that the electronic control device (15) for controlling the starting process of the internal combustion engine (10) when starting the Motor vehicle at least by means of the motor-driven generator (12) is formed. Drive device according to claim 14, characterized in that when starting the motor vehicle purely electronically at least by means of the motor-operated generator (12) the coupling of the internal combustion engine (10) is delayed, in particular impulsive. Drive device according to one of the preceding claims, characterized in that the electronic control device (15) for controlling the stopping process of the motor vehicle even without disengaging the internal combustion engine (10) of the generator (12) is formed.

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