EP2163044A2

EP2163044A2 - Motor vehicle

Info

Publication number: EP2163044A2
Application number: EP08758524A
Authority: EP
Inventors: Daniel Herrscher; Carlos Urquizar
Original assignee: Bayerische Motoren Werke AG
Current assignee: Bayerische Motoren Werke AG
Priority date: 2007-06-30
Filing date: 2008-05-15
Publication date: 2010-03-17
Also published as: DE102007030525A1; WO2009003557A3; WO2009003557A2

Abstract

The invention relates to a motor vehicle comprising a plurality of motor vehicle control devices (STE) which are singly interconnected in a ring-shaped manner on the basis of an Ethernet standard. In said motor vehicle, data is transmitted only in one direction between two motor vehicle control devices (STE) which adjoin each other in a data-related manner.

Description

motor vehicle

The invention relates to a motor vehicle with a plurality of motor vehicle control devices.

For data transmission between motor vehicle control devices, the so-called MOST bus (MOST = Media Oriented Systems Transport) has been established. It is a serial bus system for the transmission of data via optical fibers (MOST25) or via electrical conductors (MOST50). For the future in the increasing use of information technology in motor vehicles, which will include, for example, access to hard drives, the transferable via the MOST bus bandwidth is no longer sufficient.

The predominant technology for networking local computers in an office environment today is Ethernet, especially "100-Mbit Ethernet" (100BASE-TX / FX, standardized in IEEE 802.3). Based on the Ethernet standard, point-to-point Point connections and star topologies with one central switch possible.

A known Ethernet star topology is shown in FIG. Several devices STE are connected to each other via a central exchange V to exchange data. Each connection between a device STE and the switch V consists of two twisted pairs (one pair for each transmission direction, 100BASE-TX), or two optical fibers (one optical fiber (LWL) for each transmission direction, 100BASE-FX).

Devices STE with assigned or built-in 3-port switch V can also be connected in series in a "daisy-chain" to avoid the central switching device V (see Figure 7). The weight and costs for the cabling of 100BASE-TX / FX are relatively high, since two (possibly shielded) wire pairs or fiber-optic cables (including the respective plug) are required between two devices. While the cost of electronic components of the same functionality is getting smaller and smaller, the cable and plug costs for their connection remain almost constant.

A reduction in vehicle weight is a key concern in the development of modern motor vehicles.

The invention is based on the object of specifying a motor vehicle with data-exchanging motor vehicle control units, which has a low weight.

This object is solved by the features of the independent claim. Advantageous developments of the invention can be found in the dependent claims.

The invention is based initially on the recognition that the bandwidths of the known technologies used in motor vehicles for transmitting data are no longer sufficient for future requirements.

The invention is based on the idea to use the well-known from the office environment, extensively tested and a wide bandwidth enabling Ethernet standard in the motor vehicle. However, well-known Ethemet topologies (star, daisy chain) require a lot of cabling. The associated additional weight and the associated additional costs speak first against the use of the Ethemet standard in motor vehicles. The invention is based on the further idea of motor vehicle control devices by means of a simple Ethernet ring connect to each other (simply connected Ethemet ring). As a result, connection lines and thus weight can be saved. The costs can be reduced.

A preferred motor vehicle has a multiplicity of motor vehicle control devices which, in terms of data technology, are simply connected to one another annularly based on an Ethernet standard. In each case between two data-technologically adjacent motor vehicle control units, data or data frames, in particular with respect to the ring and / or physically, are transmitted in one direction only. In this way, a data exchange between two adjacent motor vehicle control units in both directions is possible: once on the direct connection between two motor vehicle control units, and once with the exclusion of the direct connection between the two motor vehicle control units "outside" on the connections between the further motor vehicle control units or between the switching units associated with these motor vehicle control units. The invention is not limited to a particular Ethernet standard or a certain Ethemetgeschwindigkeit.

Preferably, two data-technologically adjacent motor vehicle control devices for data transmission by exactly one (less than two) optical waveguide (optical Ethernet) or exactly one (less than two) twisted-pair connection (electrical Ethernet) are connected to each other to realize the simple ring.

Due to the simple ring topology, connection lines can be saved and still all connected motor vehicle control units exchange data with each other. The simple ring topology provides less bandwidth than a double ring topology or a star; but because the provided by the Ethemet standard bandwidth is much larger than, for example the bandwidth provided by a MOST bus, the bandwidth achievable by the invention is also sufficient for future data applications in motor vehicles.

A preferred embodiment of the invention provides that the motor vehicle control units each have a receiving unit for receiving (via the Ethernet ring) of data frame from a data processing adjacent motor vehicle control unit and a transmitting unit for sending (via the Ethernet ring) of data frame to a data technically associated with adjacent motor vehicle control unit. In addition, the motor vehicle control units are each assigned a switching unit which is set up in such a way that at least the data frames received via the ring, in particular broadcast or multicast data frames originating from the assigned motor vehicle control unit, are discarded, in particular not by the transmitting unit be sent.

Particularly preferred are the vehicle control units respectively associated switching unit, in particular a switching engine, transmitting unit and receiving unit elements of - the motor vehicle control unit associated - Ethemet switch (Ethemet switching device). In particular, the at least partial use of known and produced in large quantities for other applications Ethemet switches or Ethernet components, the cost can be further reduced. In Ethemet switches equipped for star topology, a send port and receive port can be disabled, left idle, or removed. In particular, the motor vehicle control unit and the Ethemet switch are located on a common board.

Alternatively, the switching unit respectively assigned to the motor vehicle control units comprises a programmable logic unit or is part of it a programmable logic unit, which is in particular an element of the motor vehicle control unit itself or advantageously shares a circuit board with the motor vehicle control unit.

Preferably, the transmission units and receiving unit respectively assigned to the motor vehicle control units are elements of a phy. The motor vehicle control unit, said programmable logic unit and / or the Phy preferably share a common board. Alternatively or additionally, the Phy may also be a part of one or the programmable logic unit, which in particular is an element of the motor vehicle control unit itself or advantageously shares a circuit board with the motor vehicle control unit.

In the following, the invention is explained in more detail by means of examples with reference to the following figures:

FIG. 1 shows a simplified representation of a star topology for

Connection of four devices;

FIG. 2 shows a simplified representation of a daisy chain

Topology for connecting four devices;

FIG. 3 shows a simplified representation of a simple ring

Topology for connecting four devices;

FIG. 4 shows a simplified illustration of a motor vehicle

Control unit with assigned Ethernet switch;

FIG. 5 shows a simplified illustration of a motor vehicle

Control unit with associated switching unit, which is implemented in a programmable logic unit; FIG. 6 shows a simplified representation of a star topology

(State of the art);

FIG. 7 shows a simplified representation of a daisy chain

Topology (prior art).

Figures 1 to 3 each show four interconnected motor vehicle control units STE. The motor vehicle control devices are, for example, navigation computer, radio, amplifier, telephone control unit.

The lines shown in dashed lines each represent a connecting line, in particular an optical fiber LWL or a twisted pair connecting line. The arrows indicate the data transmission direction. In the star topology shown in FIG. 1 and the daisy chain topology shown in FIG. 2, data-technically adjacent motor vehicle control units STE are connected to each other by two connecting lines; a trunk for each data transmission direction. In the case of the simple ring topology shown in FIG. 3, data-technically adjacent motor vehicle control units STE are each connected to one another by a connecting line.

In any scenario with at least three automotive ECUs STE, a single connected ring of automotive ECUs requires fewer connections than a star or daisy chain. The more vehicle control units in the network, the greater the savings potential. A daisy-chain with n automotive control units requires 2 ^* (n-1) connection lines (for example, optical fiber LWLs) for connecting all motor vehicle control units; a star 2 ^* n and a ring only n. Due to the saved cables, the weight and the cable and connector costs are Thernet ring in about half of the star and daisy chain topology.

FIG. 4 shows, as part of such a simple Ethernet ring topology, a motor vehicle control unit STE which is connected to an Ethernet switch ES via a connection unit (port P3), which may comprise a transmission unit RX and a reception unit TX. The Ethernet switch ES comprises as switching unit VE a switching engine.

From a data-technically adjacent motor vehicle control unit (not shown), the Ethernet switch ES receives data via a connection unit P1, in particular via the associated receiving unit RX.

These data frames are examined by the switching unit VE with regard to their origin and their destination. The data frames intended for the associated motor vehicle control unit STE are forwarded via the connection unit (port P3) to the motor vehicle control unit STE. In particular, received data frames originating from the assigned motor vehicle control unit STE itself are discarded due to a corresponding program-technical device of the switching unit. Other data frames, which are intended in particular for other motor vehicle control devices, on the other hand, are forwarded via a connection unit P2, in particular via the associated transmission unit TX, via the simple Ethernet ring to a data-processing-adjacent motor vehicle control unit (not shown). The connection units, the motor vehicle control unit and the switching unit VE can be embodied on a common board P.

The transmission unit TX of the first connection unit P1 and the reception unit RX of the second connection unit P2 are not connected and switched off on the switch side or do not exist at all. These adjustments allow standard Ethemet components to be used to create a simply connected Ethemet ring.

Each motor vehicle control device of the ring is preferably assigned an Ethernet switch with at least three ports P1, P2, P3. P1 is used only for receiving, P2 only for transmission, P3 for communication with the motor vehicle control unit. Only the Ethemet switch is responsible for the ring communication. For the motor vehicle control unit connected to P3, the ring topology is transparent. The routing tables of the Ethernet switches are arranged to circulate all data frames to the receiver's Ethernet switch (receiver-vehicle controller) and then to the receiver-vehicle controller. This is achieved by data frame with the destination address of the connected motor vehicle control unit are forwarded to P3 through each Ethernet switch, as well as all broadcast and registered by the vehicle control unit Multicastrahmen. In addition, all broadcast and multicast frames, as well as all data frames with unknown receivers are routed to P2.

To prevent data frames whose receivers do not exist and broadcast and multicast frames from circulating endlessly around the ring, the Ethernet switches are set up to discard all data frames arriving at P1 sent by the motor vehicle control unit connected to the P3 were. This can be detected by the Ethernet switch either at the sender address or another, in particular specially introduced, feature of the data frame.

An alternative implementation variant for the use of Ethernet switches is based on the use of an Ethernet Phy and a further module (For example, a FPGA), which are each assigned to a ring-participating motor vehicle control unit STE (Figure 5).

A PHY is a special semiconductor device or functional group of circuitry responsible for encoding and decoding data between a purely digital system and a modulated analog system. PHY stands in particular for the physical interface.

Associated with the Phy are a transmitting unit TX and a receiving unit RX. The switching unit VE can be realized by a suitably configured logic, in particular an FPGA. In this case, the FPGA may also be part of the motor vehicle control unit. The transmitting unit TX, the receiving unit RX, the motor vehicle control unit STE and the switching unit VE can be embodied on a common board P.

The switching unit VE is set up in such a way that:

- Data sent by the vehicle control unit data frame are passed to the Phy, and thereby sent to the next ring participant.

- From the Ethernet ring incoming data frame whose source address that corresponds to the motor vehicle control unit, be discarded.

- From the Ethernet ring incoming data frame, the destination address of which corresponds to the motor vehicle control unit, are sent to the motor vehicle control unit; This also applies to all broadcast and such multicast frames for which the motor vehicle control unit is registered. - Data frames arriving from the Ethernet ring with other destination addresses, as well as all broadcast and multicast frames that have not been discarded, are forwarded to the next ring subscriber.

Claims

claims

1. Motor vehicle

with a plurality of motor vehicle control units (STE), which are connected to one another in terms of data technology based on an Ethernet standard, simply ring-shaped,

- In each case between two data technically adjacent motor vehicle control units (STE) data are transmitted in one direction only.

2. Motor vehicle according to claim 1, wherein in each case two data-technically adjacent motor vehicle control units (STE) for data transmission by exactly one optical waveguide (LWL) or exactly one twisted pair connection are interconnected.

3. Motor vehicle according to one of the preceding claims, wherein the motor vehicle control units (STE) each have a receiving unit (RX) for receiving data frames from a data processing adjacent motor vehicle control unit (STE) and a transmitting unit (TX) for sending data frames to a is assigned to the data-technologically adjacent motor vehicle control unit (STE), and in which the motor vehicle control units (STE) are each assigned a switching unit (VE) which is set up in such a way that received data frames originate from the assigned motor vehicle control unit (STE) , be discarded.

4. Motor vehicle according to one of the preceding claims, in which the motor vehicle control unit (STE) respectively associated switching unit, transmitting unit and receiving unit are elements of an Ethernet switch.

5. Motor vehicle according to one of the preceding claims, in which the vehicle control unit (STE) respectively associated switching unit comprises a programmable logic unit or is part of a programmable logic unit.

6. Motor vehicle according to one of the preceding claims, in which the motor vehicle control unit (STE) respectively associated transmitting unit and receiving unit are elements of a Phy.