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In the third of our interactive CM Academy features we've joined forces with Bridgestone Tyres to explain how you can make your diesel go further with these simple yet effective steps...
Words: Andy Satter White fuel prices have fallen recently, the underlying requirement for improved operational efficiency remains key to all commercial vehicle operators With fuel representing in the region of 25% or more of a fleet's operating cost the impact of fuel efficiency improvements will be directly felt on your bottom line. In the latest of our CM Academies we've teamed up with Lyre giant Bridgestone to bring you an overview of the issues at play in this arena. And when you've completed your revision you can go to our online academy test area to see how much of this you've remembered.
A focus on fuel efficiency makes sense for many reasons. First, as we've said, improved fuel efficiency will affect your bottom line in a positive way. Second, you'll improve your carbon footprint, and third, you'll see operational improvements; by taking positive action to reduce your fuel bill you stand to end up with safer drivers, fewer accidents, less vehicle downtime and improved tyre wear.
There are numerous ways to reduce your fuel bill and we could fill a whole magazine Or website with the different techniques, practices and advice for using less diesel to shift your goods. However, for the purposes of this CM Academy we're concentrating on the top six ways to cut fuel costs:
1. Driving style 2. Axle alignment 3. Vehicle aerodynamics 4. Tyre maintenance 5. Tyre-rolling resistance 6. Vehicle maintenance
1. Driving style
Of all the factors we could look at in this Academy the style of driving is the one most difficult to address consistently. Let's face it, we all have bad days and in order to perform at the top of our game it requires high levels of skill and concentration. These are the attributes required of a modern truck driver, for while satellite navigation may have reduced the need for map reading and a strong sense of direction, the current art of truck driving revolves around eking out every last 10th of a mile from the gallon of diesel consumed. Correct driver recruitment procedures, an effective driver-training programme and a decent mentoring and rewards programme will pay dividends in ensuring your drivers take fuel efficiency as seriously as you do.
The key to fuel-efficient truck driving is 'momentum management', or ensuring the momentum of the vehicle is maximised so as to avoid unnecessary braking, acceleration or gear-changing. This combines with maximum vehicle safety, as drivers should always be in full control of their vehicle. Studies have shown that the improvement in a fleet's average fuel economy can be up to 13% through the use of a proper fuel efficient drivertraining programme.
The top three techniques for fuel efficient driving are: • Select the optimal gear to ensure the engine revs stay in the economical green zone on the rev counter • Employ cruise control as much as possible and where appropriate.The engine management system will control the accelerator position and ensure smooth delivery of power and maintenance of good average speed • Block shift gears when and where it is safe to do so
2. Axle alignment
Incorrect axle alignment (see graph left) will affect both fuel consumption and tyre performance. Axle misalignment can increase the rolling resistance of your truck by up to 80%, while an axle adjustment error of just 25 degrees can increase your fuel consumption by 16%. Moreover, tyre service life will be reduced by almost 20% thanks to this misalignment
3. VehicLe aerodynamics
As the speed of the vehicle increases, so the impact of aerodynamics has a higher proportional impact on fuel efficiency, while tyre-rolling resistance reduces Many bodybuilder and trailer companies have invested in maximising vehicle aerodynamics (see aerodynamics special issue CM 08 January 2009), while all the key research investigations indicate that most drag reduction comes from a correctly fined/adjusted air deflector mounted on the roof of the cab.'The key element in vehicle aerodynamics is the frontal area of your vehicle and if you don't need a high-roof truck or trailer then you will save fuel by not specifying it.
As much as 80% of the fuel economy benefits of a tractor unit's air-flow management equipment derives from just three main components: • The roof-mounted air deflector • Side collars at the rear of the cab • An under bumper air dam
4. Tyre maintenance
Correct tyre pressure will ensure the tyre is operating to its optimal design conditions and thus will ensure you get the best out of it. The rolling resistance of the tyre will be at its lowest when it is running at the right pressure, which will ensure you get the best fuel economy possible and the longest possible service life.
As well as correct tyre pressure, tyre rotation will increase tyre life and help identify any vehicle associated problems, such as misalignment, which will also affect fuel consumption. lyre rotation works because it not only extends the useful tread life of worn tyres but also counteracts or slows the progress of irregular tyre wear. There are five types of tyre rotation to consider: • Action 1: Turn the tyre on the rim in the same position Result: Counteracts one-sided shoulder wear
• Action 2: Swap wheels on the same axle Result: Equalises the impact of wear rates due to road camber or kerbing • Action 3: Swap wheels outside to in Result: Equalises tyre wear between dual wheels • Action 4: Change from one axle to another Result: Maximises tyre wear between first and second axles on a 6x2 tractor or rigid • Action 5: Reposition trailer tyres Result: Maximises life and resistance to irregular wear 5. Tyre-rotting resistance
Tyre-rolling resistance is the force purely required to roll the tyres. The forces that create rolling resistance are: • Heat dissipation inside the tyre through its deformation while running produces 80-90% • Tyre air resistance produces 0-15% • Friction between the tyre and the road produces 5% Under-inflation will have the biggest impact on fuel efficiency as the heat build-up in the tyre caused by the increased flexing of the casing and sidewall has an effect on the rolling resistance. Over-inflation will lead to uneven and accelerated tyre wear, particularly on drive axles. Either way, it will affect your bottom line.
6. Vehicle maintenance
Clearly a well-maintained vehicle will be more fuel efficient than a poorly-maintained one. Studies show a substantial fuel saving through the use of well-maintained vehicles and here are four tips for improving fuel usage through your maintenance procedures: • Check records for rapid wear of clutch or brake parts • Likewise any fuel/oil leaks and signs of fuel spillage on the tank • Black smoke suggesting possible faults with the engine • Damage to the body work of a truck/trailer can increase aerodynamic drag. •