The truck industry is searching high and low for solutions that cut fuel consumption. One method is to use the vehicle's kinetic energy to propel the truck. Now Volvo Trucks has developed I-See, which operates like an autopilot and takes over gearchanging and utilises gradients to save fuel.
Kinetic energy is the mechanical work needed to reduce an object's speed to zero. When an object in motion is slowed down, its kinetic energy has to be transformed into some other form of energy. When a vehicle brakes, its kinetic energy is converted into heat. Many manufacturers in the automotive world are now examining solutions for harnessing kinetic energy instead of releasing it as surplus heat.
"If kinetic energy can be exploited to a greater extent, it may help cut fuel consumption," said Anders Eriksson, product developer at Volvo Trucks. "This will benefit both the environment and the industry's economy, something that is very important today as fuel costs are becoming an increasingly heavy burden on many haulage firms."
And it is precisely this that Volvo Trucks has succeeded in developing with its new I-See solution. The system harnesses the truck's own kinetic energy to "push" the vehicle up hills. On downhill gradients the same energy is used for acceleration.
Kinetic energy can save five percent
I-See is linked to the transmission's tilt sensor and obtains information about the topography digitally. The fact that the system is not dependent on maps makes it more dependable since it always obtains the very latest information. I-See can recall about 4000 gradients, corresponding to a distance of 5000 kilometres.
"I-See is an autopilot linked to the truck's cruise control, taking over and handling gearchanges, throttle and brakes on gradients, ensuring they all operate in the most fuel-efficient way possible," said Hayder Wokil, product manager at Volvo Trucks. "I-See freewheels as much as possible – so on certain stretches of road no fuel is used at all."
"In this way fuel consumption can be cut by up to 5 percent," Wokil said. "This figure is based on the results of simulations and tests on public roads. I-See requires use of the cruise control, and we know that on average drivers use cruise control about half the time. For a truck in normal operation, covering 140,000 kilometres a year, the saving will be about 1000 litres of fuel annually. This makes a big difference to the haulage firm's profitability."
Biggest effect on small hills
I-See carries out six different operations to utilise the kinetic energy to the very maximum. For instance, I-See accelerates up hills, remains in a high gear for as long as possible and freewheels on descents to exploit the truck's weight as a propulsion motor.
"I-See works best in undulating terrain," said Eriksson, who was responsible for the development of I-See. "With moderately long and steep slopes, I-See ensures that you can freewheel for long distances without using the engine."
"It is this freewheeling capability that makes the system special," he added. "When the truck rolls freely, virtually no fuel is used. But in order to freewheel, a whole lot of data is required. It imposes high demands on precision. For instance, you have to know whether your speed will drop or increase over the next stretch of road. A gradient of just a few per cent can be the decisive factor."
Other factors that make a difference are air resistance and the truck's weight. All told the system has to keep track of and process a lot of information. Many truck drivers who test I-See will recognise the driving style it adopts.