The physics behind Eco-Driving


Some people want to learn eco-driving techniques to save money on fuel and others because they are concerned about the environment and wish to reduce their Co2 emissions’ discharged from their exhaust pipes. Whatever your motivation understanding eco-driving as a technique to reduce fuel consumption needs practice and self-monitoring to achieve financial and environmental benefits to the driver.

A key rule of Physics in relation to driving, is that minimizing changes in kinetic energy reduces its consumption. The more smoothly you change speed - whether to accelerate or slow down – the greater the fuel economy you achieve.

Eco-driving is a series of driving steps and anticipatory judgements that are aimed at keeping your vehicle moving with the least resistance possible. The aim is to achieve maximum forward motion for the least amount of spent energy in the form of fuel.

The first step is to understand the basic principles of vehicle mechanics, drag factors and aerodynamics and how they inter react with each other in order to achieve high millage for the minimum cost.

To illustrate this concept, think about the energy you exert or conserve when you are riding a bike. Yes - you may have two wheels instead of four, but you have the same basic mechanics, drag factors and aerodynamics that come into play in order to power the wheels in a forward motion. Your body exerts the energy needed (engine) your physique and bike frame hinders of helps forward motion (aerodynamics) and your use of gears, brakes and tyre inflation can either enhance momentum or produce drag.

If you think about expending energy as wisely in your car as you do when you ride a bike, you should automatically become adept at driving ecologically and efficiency keeping in mind these cycling techniques.

Driving to save energy - Think Bike

  • Make sure your tires are properly inflated and your vehicles engine is well tuned and is in good mechanical condition which will reduce rolling and mechanical resistance. (you dont normally go for a bike ride when you're feeling ill or cycle on flat tires. Why not ? Because it's a waste of energy.
  • Moderate your braking. Eco-driving teaches you to increase the distance when approaching stops (when cycling you don't furiously pedal towards traffic lights and road junctions and then pull on the brakes, Why not? Because it’s a waste of energy).
  • Graduate your speed on hills. “Graduate speed.” means that as you climb small hills or inclines on motorways and dual carriageways, you very slowly and gently accelerate to moderate the load on the engine. In effect you steady your speed on the climb to gradually build up momentum until you reach the crest of the hill where you ease off the accelerator letting the energy and inertia of the cars forward motion carry your car over the peak rather like a roller coaster where you can then engage a higher gear as you pick up speed on the down side. (you don't usually power up hills on your bike trying to maintain your previous cruising speed that you achieved on the flat, Why not? Because it’s a waste of energy)
  • Eco-driving teaches you to save energy by mimicking cyclists who are highly attuned to the relationship between aerodynamic drag and the energy needed to travel at optimum speed.
  • Cyclists know that the most efficient way to cycle is at a steady pace (not a slow pace) which requires the least amount of energy to arrive at their destination relaxed and on time. 

Practice one technique at a time until it is second nature and continue with the second, third and so on. Within a few months, you will begin to achieve  hybrid car-like fuel economy, Now that you understand the principle behind eco-driving, why not read our other tips and advice in the series to help you master the techniques which will reduce your Co2 and save you money.

Click to read further in this series - What is Eco-Driving?

The physics behind Eco-Driving The physics behind Eco-Driving The physics behind Eco-Driving