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Drive-by-Wire ( DbW for short ) is the term for (at least partial) driving or controlling of vehicles without mechanical power transmission from the operating elements to the corresponding control elements such as throttle valves . The drive-by-wire concept comprises at least two or more of the “ X-by-wire ” systems such as brake-by-wire (brake control) and steer-by-wire (steering).

According to the name, there are no mechanical connections. Functions are controlled via electrical cables and servomotors or electromechanical actuators . It can lead to lower fuel consumption if there is no need to operate energy-intensive hydraulic or mechanical systems.

The more recent development in motor vehicle construction tends to forward all driver commands only electrically. Shift-by-wire systems are now in series, but laws make the use of purely electrical systems for both steer-by-wire and brake-by-wire more difficult, so there are currently only extensive studies. Problems with these systems would be a failure of the electrical supply, for example, which could lead to total inoperability or brake failure.

For security reasons, it must above all be possible to transfer the data quickly and in parallel over several independent lines redundantly . Here the transition to the FlexRay bus in the vehicle should overcome problems of the CAN bus .

Electronic power control

Electronic Power Control (in short "EPC"), also known as "drive-by" or "electronic accelerator" is a Drive-by-wire control system in motor vehicles with petrol engine the throttle cable replacement.

Function and structure

In petrol engines without EPC, the throttle valve , which can be used to control the engine speed and torque, is connected to the accelerator pedal by a cable system. In vehicles with EPC, the accelerator pedal position is recorded by a potentiometer and the value is electronically forwarded to the engine control unit. The throttle valve is moved electronically by a stepper motor . As a result, the accelerator pedal no longer has direct access to the throttle valve, but only informs the control unit of the driver's drive request.

As a result, the engine control unit has unlimited influence on the throttle valve position and thus the torque of the engine at all times and can therefore react faster and more precisely to changing conditions (such as emergency operation, locking, intervention by ESC , ASR, EDL, overrun mode, cruise control mode). Earlier mechanical control systems that influence the engine torque by changing the injection or ignition timing can be replaced by the EPC system. A faulty EPC system is indicated by a warning light in the instrument cluster . In some systems, the EPC goes into emergency mode at a permanently increased speed (e.g. VW and Audi, 1500 rpm).

The Honda NSX had a DBW system as early as 1995



The Honda NSX was in 1995 the first production car that is both electronic throttle control ( E-gas , combined with the regulation of cruise control and the PGM-FI - manifold injection ), as well as a fully electronic power steering had. The DBW system enabled the engine to respond more quickly to accelerator pedal commands and more precise control of the traction control .

The first serial application of a DBW system was pioneered by BMW in 1987 in the E30 in conjunction with its M21 turbodiesel engine, which can be selected from 1987.

Engine-dependent DBW: BMW E30

One example of the consistent use of drive-by-wire technology is the Toyota Prius hybrid vehicle .

The Toyota Prius has extensive DBW technology


In the meantime, there is also a trend towards electrical transmission of driving signals in motorcycles. Here, however, the term “ride-by-wire” is generally used. Yamaha ( YZF-R6 2006) and KTM ( 690 Duke 2007) brought the electronic throttle valve control "YCC-T (Yamaha Chip Controlled-Throttle)" and "EPT (Electronic Power Throttle)" respectively. Here, the throttle cable remained and it was already possible to use different driving modes, such as. B. to realize cautious response of the engine in the rain or direct throttle response in Sport mode: Yamaha's D-Mode (Sport, Town), KTM's MTC (Motorcycle Traction Control) mode (Street, Sport, Rain) and Aprilia's Tri-Map (Sport, touring, rain; see: SL 750 Shiver ). For the first time, the 690 Duke 2012 , “the first motorcycle with a real RBW system”, “buried the classic, mechanical connection between the throttle grip on the right handlebar end and the slide in the carburettor or the throttle valve body”. The position of the throttle grip is recorded electronically and forwarded to the engine and the throttle valve. In the meantime, other models and brands also offer this technology: for example the KTM 1190 Adventure (also has “[four] different MTC modes”: Sport, Street, Rain, Offroad, Off-Mode); similar to the R 1200 GS from BMW (Rain, Road, Dynamic, Enduro, Enduro Pro) presented at the same time .

Vehicles for the disabled

The drive-by-wire concept is also relevant for adapting vehicles to people with physical disabilities . Various installation solutions enable people with low residual forces, a high cross-section, minimal mobility and even without arms or legs to drive a car with Space Drive 2. Microprocess-controlled input devices make it possible to operate the brakes, accelerator and steering. These driving aids transmit the signals in nanoseconds to two servomotors for brakes and accelerator and to two others for the drive-by-wire system. The first retrofitted drive-by-wire system with street approval was the Space Drive 2 with triple active servo redundancy from the German company Paravan GmbH.


One of the main sources of injury in a car, the steering column, is eliminated when driving with drive-by-wire. The complex motor coordination of legs and arms is eliminated with this system. In addition, in a car, control from both the driver and the passenger side is possible without any problems.

Web links

See also


  • Expertise in automotive engineering . 29th edition. Europa-Lehrmittel, 2009, ISBN 978-3-8085-2239-4 .
  • Kai Borgeest: Electronics in vehicle technology . 1st edition. Friedr. Vieweg & Sohn Verlag, Wiesbaden 2007, ISBN 978-3-8348-0207-1 .

Individual evidence

  1. § 38 Steering Device Paragraph (1) StVZO
  2. § 41 Brakes and wheel chocks, Paragraph 1 StVZO
  3. Robert Glück: No more trains, but electronics . In: Motorrad online . June 8, 2012. Retrieved July 5, 2014.
  4. ^ MTC (Motorcycle Traction Control) . In: KTM-Sportmotorcycle AG . Archived from the original on July 4, 2014. Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved July 6, 2014. @1@ 2Template: Webachiv / IABot /
  5. Driving modes. As optional equipment ex works . In: BMW Motorrad International . Archived from the original on July 14, 2014. Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved July 5, 2014. @1@ 2Template: Webachiv / IABot /
  6. Paravan: Space Drive Technology. Retrieved September 6, 2012 .
  7. Joysteer: Drive-by-Wire when steering and braking a vehicle. (PDF; 4.6 MB) (No longer available online.) Archived from the original on June 15, 2013 ; Retrieved September 6, 2012 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot /
  8. Drive-by-Wire including street legal - Paravan: Space Drive technology. Retrieved September 9, 2015 .