Most vehicle functions are managed electronically. The control units receive inputs from the control switches and pushbuttons and information from the sensors. They transmit signals to the control apparatus (air, hydraulic or electrical relays) and indicators (analogue or digital elements, telltales).
Fewer wires and more functions
The interaction between the control units, which is impossible with a conventional electrical system, is possible because the signals are digital and because they are transmitted by CAN lines. Compared to an ordinary system, the number of wires, fuses and relays has been cut by 40-50%. For example, the passenger side window opening can be controlled by the panels on the right and left doors, but also from the bunk in the Active Time cab. A conventional circuit would need a relay onto which three different lines would converge, in addition to the line to the window winder motor. With the new system, each panel has its own management units, which transform the impulse from the switch into a signal that circulates through a CAN-bus line until it reaches the control unit of the door.
The number of functions can also be significantly increased. It is possible to operate the radio from the steering wheel and to view the station on the instrument panel monitor. The driver receives information about vehicle performance (average speed, instantaneous and average consumption). Even the diagnostic possibilities have been boosted. So much information is transmitted that priorities have to be established. Every piece of information is attributed a degree of importance: those related to safety have precedence over any other information, which is memorised until it can be processed.
The CAN-bus system is divided into four sections: ‘driveline’, ‘cab and frame’, ‘instruments’ and ‘radio / communications’. For example, the CAN-bus lines of the chassis link the engine, the automated gearbox, the Intarder, the EBS braking system, the Ecas air suspension control, the anti-theft system and the speedometer sensor. The CAN-bus lines are linked by two control units in the cab. A special control unit has been added on the chassis for bodybuilders, which contains all the terminals necessary to connect the lights, the power take off controls and the telltales on the instrument panel.
Telematics: remote fleet management
Using the GPS system to trace vehicles has two advantages. It allows a vehicle to be located for fleet management and, thanks to the information in the tachograph, it allows the driver's working times to be verified and recorded. For fleet management, transmitting functional data regarding the vehicle makes it possible to programme maintenance work. A VDI (Vehicle Data Interface) is envisaged on every Stralis, which can be connected to an onboard computer from a specialist supplier. Iveco has developed a procedure that verifies the equipment available on the market. Each European country is currently appointing one or two qualified suppliers.
Thanks to the electrical and electronic equipment on the Stralis, the driver has all the information he needs to optimise driving. The data received from the electronic control units are memorised in a "black box" that can be used for fleet management. They can be recovered whenever the vehicle returns to base, or day by day by a GPS transmission system.
What is more, the fact that the controls (cruise control, Intarder, external light clusters) are grouped around and on the steering wheel (scrolling menu controls of the on-board computer and the radio), allows the driver to keep his attention on the road and reduces reaction times in the event of unexpected occurrences, which enhances safety