These days we are all feeling the pinch of constantly rising fuel prices, and we would all like to use less fuel if we could. Fortunately, and even though modern cars are still only about 30% fuel efficient at best, there are many proven ways to convert the energy in every drop of fuel into motion, and in most cases, these tips and tricks won’t cost you anything above and beyond what you would normally spend on routine car maintenance.
However, spending some additional money may be unavoidable initially, but over time, these expenses almost always pay for themselves in terms of fuel savings. Thus, if you are interested in improving your car’s fuel efficiency, here is how to do it-
Take your car for a diagnostic check-up
It should be remembered that not all faults/defects/malfunctions that affect fuel efficiency set trouble codes and illuminate warning lights to alert you to the fact that something has gone wrong. Therefore, the object of this exercise is to identify incipient problems that might become actual issues later on. In this context, a diagnostic check up would typically focus on the following-
Checking fuel trims
Fuel trims come in two “flavours”; short term fuel trims that refer to the adaptations the fuel management system makes to the air/fuel mixture in response to throttle inputs, and long-term fuel trims that are related to the efficiency of the catalytic converter(s) on a vehicle.
The oxygen sensors that monitor and control these adaptations to the air fuel mixture can, and do lose some sensitivity after long use, which means that the input data they supply to the vehicle’s engine and fuel management systems is no longer accurate. As a result, the engine and/or fuel management systems(s) can in some cases over compensate to restore the balance of air relative to fuel, which often translates into reduced fuel efficiency. In most cases, the issue can be resolved by replacing the oxygen or air/fuel ratio sensors.
Checking the ignition system
As with the fuel trims, not all ignition system related faults necessarily set fault codes and illuminate warning lights. Some types of ignition coils break down over time, which reduces the strength of the spark they deliver to ignite the air/fuel mixture. Weak sparks translate into poor combustion, which in its turn, translates directly into poor fuel economy, and especially on engines that use multi-spark ignition technology.
Inefficient ignition coils can be identified with an oscilloscope by any competent mechanic, but note that replacement of poorly performing ignition coils is the only reliable remedy.
Reduce internal friction
Since a large percentage of an engine’s heat is created by friction between moving parts, it makes sense to reduce friction as much as possible. While friction cannot be eliminated altogether, it can be reduced by as much as 50% simply by switching over to synthetic engine oil, which provides about twice the lubricity of even the most advanced mineral oil. Improved lubrication translates directly into less friction, which means that less fuel is required just to keep the engine turning over.
Reduce rolling resistance
A car’s resistance to movement is known as its “rolling resistance”, which is (for the most part)a combination of the car’s weight, and the amount of friction present between the tires and the road as a function of how well (or otherwise) the wheels are aligned both with respect to each other, and to the vehicle’s thrust line, also known as its longitudinal axis. Here are the best ways to reduce rolling resistance, and reduce fuel consumption at the same time-
Keep the wheels properly aligned
Poorly aligned wheels usually manifest as uneven wear on the tires, but not always. In some cases, the misalignment may be marginal, which may take a long time to become visible as uneven tire wear. Nonetheless, even marginal misalignments increase a vehicle’s rolling resistance, which requires more fuel to overcome. To prevent marginal misalignments from developing, have a proper, 4-wheel alignment done every time you have the oil changed.
Maintain proper tire inflation
All tires are designed to perform optimally, and to exert the least amount of friction on the road when they are inflated to their recommended pressure. Therefore, do not rely on the vehicles’ tire pressure monitoring system to maintain tire pressure; these systems are notoriously (and even dangerously) inaccurate and/or unreliable, and a tire may by underinflated by as much as 20 to 25 percent before a tire pressure monitoring system recognises a problem.
Thus, invest in a good quality digital tire pressure gauge, and check/adjust the inflation pressure of all tires (including the spare) at least once a week when the tyres are cold. You will notice the difference at the fuel pump almost immediately.
Lose some weight
Lugging around unnecessary weight in the form of golf clubs, sports kit, or anything else you do not need to have in the vehicle increases the vehicle’s weight, which increases its rolling resistance, which in turn, requires more fuel to overcome than is strictly necessary.
Adapt your driving style
While all of the above measures will deliver a measurable improvement in your vehicle’s fuel efficiency, the biggest improvements can be made by adapting your driving habits and/or style, which does not cost anything. Here are the two most important things to keep in mind-
Increase your following distance
Doing this allows you to “read” the traffic flow ahead of you, and if you get it right, you can eliminate a lot of standing starts and/or unnecessary accelerations, both of which (can) consume about twice the amount of fuel you would use at a steady cruising speed
Use the highest possible gear at any given speed
By using the highest available gear without lugging the engine on a manual gearbox, you are using the vehicles’ gearing to convert most of the calorific value of the fuel into motion. This is roughly analogous to pedalling a bicycle; at some point, the energy you put into the pedals reaches a point of diminishing returns- in the sense that the energy you put in no longer contributes to the bicycle’s motion.
The same thing happens with a car. At a certain point in the lower gears, the engine speed no longer contributes to the car’s motion, which means that you are unnecessarily burning fuel that cannot be converted into as much motion forward motion as would be possible to do in a higher gear.