EP1295029A1

EP1295029A1 - Starter device for an internal combustion engine

Info

Publication number: EP1295029A1
Application number: EP01949251A
Authority: EP
Inventors: Gerhard Koelle; Simon-Florian Czerny; Manfred Ackermann
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2000-06-16
Filing date: 2001-06-09
Publication date: 2003-03-26
Also published as: WO2001096735A1; US6531787B2; US20020163197A1; KR20020026372A; DE10029714A1; JP2004503711A

Abstract

The invention relates to a starter device (1) for an internal combustion engine (2). Said starter device is provided with an electric starter motor (3), a power supply (16), and with a drive device (4) for the starter motor (3). The drive device comprises a power switching electronic unit (6) and a control device (5) for the power switching electronic unit (6). Sensors for detecting physical parameters that are relevant for the starting power of the starter motor (3) are provided in order to optimally modulate the starting characteristic curve of the starter motor (3) within permissible limiting values of the physical parameters.

Description

Starter device for an internal combustion engine

The invention relates to a starter device for an internal combustion engine with an electric starter motor and a voltage supply and a control device for this starter motor.

The usual conventional electric starter motors are generally commutator direct current motors with permanent magnetic or electrical excitation. The voltage supply is ensured via the vehicle electrical system of the vehicle equipped with the internal combustion engine from its battery.

As a control device for the starter motor is usually a more or less complex Sch teremrichtung used, which is coupled to the ignition lock of the vehicle and actuated via an actuation of the ignition key beyond the switch position "ignition on".

Conventional starter devices according to the prior art now have a design characteristic which is tailored to the starting power at the so-called starting limit temperature. Due to the fact that they are only operated for a short time, they are not designed for continuous output, which consequently makes theological overload protection unnecessary. Due to this design characteristic, well-known large-series starters are cost-optimized and tailored relatively strongly to the respective application.

As is known, starter devices are faced with conflicting requirements due to their operating conditions. One example is the so-called "cold start problem". At very low The Staiter motor itself should provide a high level of mechanical performance at ambient temperatures, since the internal combustion engine is very stiff due to the viscous lubricant and therefore running properties characterized by high frictional forces. This requires high starter performance, which can be achieved by appropriately extracting energy from the power supply using the on-board battery. However, especially at low ambient temperatures, the available electrical energy of the on-board battery is severely limited, so that there are no excessive power requirements to avoid a breakdown of the battery.

On the basis of the problems described by way of example, the invention is based on the object of specifying a starter device for an internal combustion engine which is capable of being operated flexibly as a function of different operating conditions in order to combine the starting conditions, in particular the starting power and the steadiness improve the lifespan of the starting system. In particular, conventional starter motors in the form of cost-optimized large-series units should still be able to be used.

According to the characterizing part of claim 1, this object is achieved by a characteristic configuration of the control device. The latter accordingly has power switching electronics, a control unit, the control output of which is connected to the control input of the power electronics, and sensors connected to the inputs of the control unit for detecting physical parameters relevant to the starting power of the starter motor. The control unit optimizes the start characteristic for the activation of the on the basis of the parameters recorded by the sensors Start motor within the permissible limits of the physical parameters. In particular, party performance is maximized.

The start characteristic can thus be controlled in summary so that no limit values, such as mechanical limit values in the form of maximum speeds of the starter motor, thermal limit values in the form of permitted maximum temperatures of the starter motor, magnetic limit values, such as those caused by the starter motor during the starting process flowing current are characterized, and defined electrical limit values are exceeded by the so-called brush fire and commutation.

In a preferred embodiment of the invention, the characteristic values can then be within the permissible limit values of the physical ones. Parameters are set to optimal parameters developed and defined for the respective starter type and certain start cases.

According to further preferred developments of the subject matter of the invention, temperature sensors for detecting the temperature of the internal combustion engine and / or the starter motor are provided as physical parameters. In addition, or alternatively, a current measuring device for detecting the current flowing through the starter motor during the starting process, a torque sensor for detecting the torque of the starter motor during the starting process and / or a speed sensor for detecting the speed of the starter motor during the starting process can be provided. In this way, for example, depending on the starter temperature, the characteristic values with respect to the output can be regulated and adapted as a function of the temperature of the internal combustion engine. According to further preferred embodiments, the start characteristic can be controlled differently depending on different speed ranges. In the low speed range, the starting characteristic curve can be controlled as a starting current / torque limit depending on the permissible degassing limit of the starter motor magnets. In the medium speed range, the start characteristic curve can in turn be controlled as a start torque / torque limit depending on the permissible wear values caused by the brush fire, the starter temperature and / or the temperature of the internal combustion engine. In the area of higher speeds, the start characteristic can be modulated depending on the permissible mechanical limits of the starter motor due to centrifugal force.

In all control processes, the start curve can preferably be recorded by the control device and the characteristic values can be changed, in particular in order to improve the next start cycle. In connection with a false start, this means that the characteristic curve values are changed in the sense of an improvement in the start so that a repeat start is mitiied with the new characteristic curve values.

In summary, the subject matter of the invention with its preferred developments over the stator devices according to the prior art offers the following advantages:

- A performance increase of at least a factor of 2 can be achieved. - In particular, the increase in the hot state output in the medium speed range leads to improved start-up support as well as shortened starting times and improved starting behavior of the internal combustion engine. - The start characteristic curves can be adapted to the parameters that have been worked out and optimized for the design.

- At cold start temperatures, the start energy can be reduced to protect the battery. - Start current peaks and consequently start power peaks are avoided.

- The party device offers an integrated, thermal, mechanical and magnetic overload protection. The number of different starter types for different vehicles and internal combustion engines can be reduced by adapting the control unit parameters for a fixed hardware Kormgurarion to the respective vehicle data.

- The starter devices can generally be reduced in size compared to conventional systems with at least constant starting power.

Further features, details and advantages of the invention can be gathered from the following description, in which an exemplary embodiment of the subject matter of the invention is explained in more detail with reference to the accompanying drawings. Show it:

Fig. 1 is a block diagram of a Startervomchtung, and

Fig. 2 is a graph showing the current or torque characteristic of the starter device as a function of the speed of the starter motor.

The starter device designated as a whole in FIG. 1 serves for starting an internal combustion engine, such as, for. B. a gasoline engine. The heart of the starter device 1 is, on the one hand, an electric starter motor 3, which can be a large series unit in the form of a so-called commutator DC motor. Furthermore, a control device, designated as a whole by 4, for the starter motor 3 has a control unit 5 and power switching electronics 6. This has a MOS-FET power semiconductor 7, which drives the starter motor 3 in a clocked manner in the usual manner. The control of the LeisrangsschaltelektiOnik 6 takes place via the control output 8 of the control unit 5, which is connected to the corresponding control input 9 of the power switching electronics 6.

Various sensors 11, 12, 13, 14, 15, 20 are coupled to the various inputs 10.1 to 10.5 of the control device 1 and are used to detect physical parameters relevant for the starting power of the starter motor 3. Thus, the internal combustion engine 2 is assigned a temperature sensor 11, which provides an electrical signal & _VM representative of the operating temperature of the engine 2. Likewise, a temperature sensor 12 is provided on the starting motor 3, which outputs an electrical signal θ _S τ representative of the temperature of the starter motor 3 to the control unit 5.

In order to detect the current flowing through the starter motor 3 when the starter motor 3 is actuated via the power electronics 6, a current measuring device 13 is connected in series with the starter motor 3 in the current branch 14. This generates representative electrical signal I _sτ for the flowing current I.

Finally, a torque sensor 15 is arranged on the starter motor 3, which _{detects the} torque generated by the starter motor 3 during the starting process and _{outputs it} to a corresponding signal M _sτ at the input 10.4 of the control unit 5. The starter motor 3 is also provided with a speed sensor 20, which emits a signal representative of the speed ni w at the input 10.5 of the control device 5. As can still be discussed with reference to FIG. 2, the characteristic curve of the starter motor 3 is appropriately modulated as a characteristic value as a function of the starter motor speed.

The starter motor 3 is supplied with voltage via the on-board battery 16 of the vehicle, a free-wheeling diode 19 being connected in parallel with the series connection comprising the starter motor windings 17, 18 and the current measuring device 13.

In this context, FIG. 2 shows a diagram of the dependencies of the current I flowing through the starter motor 3 during the rigid process or of the torque M developed in the process as a function of the rotational speed n w. The diagram also indicates various limits. The demagnetization limit E is shown in broken lines. In the sense of optimizing the starter motor control and the characteristic curve used, it should be noted with regard to the demagnetization limit E that an increase in performance of conventional large-series starters z. B. is possible by using more powerful magnets. The maximum current flowing in starters customary today - the short-circuit current - is avoided in the invention by correspondingly controlling the starter motor with a certain limiting current. The demagnetization is therefore determined by the limiting current, which can be optimally adapted to the respective starter. To increase the power, the starter can also be operated at a higher voltage without being damaged, since all relevant limit values, in particular the demagnetization limit E, can be maintained by a suitable regulation of the limiting current. This is represented by the torque characteristic curves MKL1 drawn continuously in FIG. 2 for operation on an on-board voltage of 12 V or MKL2 for operation on an on-board voltage of> 12 V. In all cases, the limiting current must be selected so that the torques are secured at the operating point. This value is typically a factor of 2 below the value of the short-circuit current.

The colon according to FIG. 2 also shows the so-called commutation limit K, which is determined by the maximum permissible brush fire on the commutator, with a colon-dash line. The brush fire, in turn, determines the groove for the commutator life. Here, too, a maximum line can be controlled via the control device 5 starter-specific and regardless of environmental parameters.

The last relevant limit is indicated by the dash-dotted line, the mechanical limit M, which is, for example, at a speed nw of the starter motor 3 of 600 min ⁻¹ the maximum values are largely exploited via the control at each temperature of the starter motor 3 or the internal combustion engine 2, while in a conventional starter control, for example, the permissible starting power at sub-zero temperatures is severely limited by the centrifugal force limit on the warm starter. A representative target characteristic curve S, which is regulated by the control device 5, is indicated in the diagram according to FIG. 2 by a wide-ranging locking line. From this it is clear that in a low speed range the start characteristic is controlled as a start current / torque limit depending on the permissible demagnetization limit E of the start speed. The starting current I is limited to approximately half the 1000 A demagnetization limit. The representative branch of the target characteristic curve S is labeled with I.

This is followed in the middle speed range by branch II of the Soh no-line, which is controlled as a function of the commutation limit K - that is, taking into account the permissible wear caused by the brush fire. The temperature of the stator motor 3 and the internal combustion engine 2 can also be included here, for example to implement thermal overload protection for the starter motor 3.

Finally, in the area of highest speeds, the SoU core S is controlled in such a way that a certain safety distance remains from the mechanical limit M (see branch JH of the nominal characteristic curve S).

If a starting process is carried out with such a desired characteristic curve S, the starting behavior of the starter motor 3 or the internal combustion engine 2 can be detected via the engine control electronics and, in the event of any problems, a change in the characteristic values and modulation can be carried out in order to perform a next starting process To achieve improvement. In particular in the event of a false start, it can thus be attempted to repeat the start with improved parameters.

Claims

claims

1. Starter device for a combustion machine with an electric starter motor (3), - a voltage supply (16) for the stalter motor (3), a control device (4) for the staitter motor (3), characterized in that the control device (4) has a Power switching electronics (6), - a control unit (5), the control output (8) with the control input

(9) the power switching electronics (6) is connected, and sensors (11, 12, 13, 15, 20) connected to the inputs (10) of the control unit (5) for detecting physical parameters relevant for the starting power of the stalter motor (3) , The control device (5), based on the parameters detected by the sensors (11, 12, 13, 15, 20), the starting characteristic (5) for the activation of the starter motor (3) within the permissible limit values (E , M, IC) of the physical parameters, in particular maximized.

2. Staltervorrichtung according Anspmch 1, characterized in that the start core line (3) is adaptable such that the characteristic values within the permissible limit values (E, M, K) of the physical parameters can be set to fixed values.

3. Staitervomchtung according to Anspmch 1 or 2, characterized in that a first temperature sensor (11) for detecting the temperature of the Veihrermungsmaschine (2) is provided as a physical parameter.

4. Starter device according to one of claims 1 to 3, characterized in that a second temperature sensor (12) for detecting the Temperami "of the starter motor (3) is provided as a physical parameter.

5. Switching device according to one of claims 1 to 4, characterized in that a current measuring device (13) is provided as a sensor for detecting the current flowing through the starter motor (3) during the starting process as a physical parameter.

6. Starter device according to one of claims 1 to 5, characterized in that a torque sensor (15) for detecting the torque (M) of the starter motor (3) is provided as a physical parameter during the starting process.

7. Starter device according to one of claims 1 to 6, characterized in that a speed sensor (20) for detecting the speed (nκ v) of the starter motor (3) is provided as a physical parameter during the starting process.

8. Starter device according to one of claims 1 to 7, characterized in that the starting characteristic (5) in the range of low speeds as starting current / torque limitation depending on the permissible demagnetization limit (E) of the starter motor magnets can be controlled.

9. Starter device according to one of claims 1 to 8, characterized in that the starting characteristic (5) in the range of medium speeds Starting torque / torque limitation depending on the permissible, brush fire-related wear range, the starter temperature and / or the temperature of the internal combustion engine (2) can be controlled.

10. Starter device according to one of claims 1 to 9, characterized in that the starting characteristic (5) in the range of higher speeds than starting torque / torque limitation depending on the permissible, centrifugal force-related mechanical limit values (M) of the starter motor (3) is controllable ,

11. Starter device according to one of claims 1 to 10, characterized in that the start profile can be detected by the control unit (5) and the characteristic values can be changed, in particular in the sense of improving the next profile profile.