The adoption of electronic units to control the principal parts of the vehicle – engine, gearbox, braking and suspension – and the need to interconnect these had already led Iveco to use Can-Bus lines in the past, for the transmission of codified data. It thus seemed opportune to apply the same technique to the vehicle’s entire wiring system, which was getting increasingly complex with the addition of new functions, the transmission of diagnostic information and planned telecommunications networks, remote diagnosis and satellite positioning.
The new system links all the switches, devices and sensors and transmits controls and detection functions, showing them on the gauges, the dashboard-mounted screen or the display lights. Apart from the Can-Bus line, which controls transmission and braking, the system features three new CAN-bus lines and eight control units inside the cab and on the chassis. Each control unit converts the signals from the Can-Bus lines and sends them to the components through traditional wiring. The signals travelling in the opposite direction, from pressure sensors (detecting air pressure in a tank, for example), level detectors (in the case of levels of fuel or windscreen washer, for example) or controls (the insertion of power take-off, for example) are transmitted via a traditional circuit to the control unit. Here they are converted into codified signals, which will be transmitted on the Can-Bus line to the main control panel, and from there to the dashboard. Once at the dash the signal is converted into digital format on the screen (in the case of air pressure), or electrical energy to feed a dial (in the case of fuel level) or an indicator light (in the case of windscreen washer or power take-off engaged).
The new system goes a long way to simplifying the wiring between the cab and the chassis, as well as inside the cab itself. This translates into increased fitting reliability, as well as having the advantage that only a single cable has to be protected and it is easier to diagnose failures. For example, the window on the passenger side is controlled by switches on the left and right doors, as well as from the control panel in the rest area. A traditional circuit would mean a relay along three lines, with a fourth connected to the window mechanism. With the new system, each switch has its own wire, which converts the impulse into a signal to circulate on the Can-Bus lines to reach the door controls. The amount of information that can travel on Can-Bus lines is so great that priorities had to be established. Each type of information was accorded a level of importance: safety information goes first, while other data is stored in the memory and processed subsequently.
Thanks to the new system, the driver has all the information on the vehicle functions (average speeds, current and average consumption etc) necessary to achieve optimum driving performance. The data that flow in from all the vehicle’s central processing units can also be stored in a black box for use in fleet management.
Moreover, having the controls grouped around the steering wheel (speed limiter, braking, and headlights) and on the wheel itself (menu commands, radio and telephone) means that the driver’s attention is not distracted from the road. Thus reduces reaction times in the case of something-unexpected happening, an undisputed advantage in terms of safety.
A system of this kind can only be achieved with a conversion system, which interfaces with the cab’s Can-Bus line.
