After the substantial 10 sen per litre increase as August started off, the price of RON97 petrol has eased a bit for the coming 7 days. It will be 3 sen per litre cheaper, bringing the pump price down to RM2.61. This is the level it was at during the second week of June.

The prices for RON95 petrol and diesel, both Euro2M and Euro5, remain unchanged and the government has said that it will maintain prices till the end of the year at least. Should the prices have to go up, the government will provide subsidies to maintain them at their current levels. For the Euro5 grade of diesel, there is an additional charge which is still 10 sen but the extra will be worth it as the fuel is much cleaner. The engine will run better and you’ll also be doing the environment a favour as the sulphur content is extremely low.

This week’s fuel-saving topic is about the effect of aerodynamics and how it can save fuel. For many decades now, vehicle designers have paid a lot of attention to shaping a vehicle body so that it can slip through the air with as little resistance as possible. The reason is simple: if the vehicle encounters less wind resistance, it needs less power to attain a desired speed. Less power means less fuel consumed, stretching the distance that each litre can go.

Generally, all modern vehicles – even pick-up trucks – have been shaped with good aerodynamics in mind. However, practicality must also be considered to the most aerodynamic shape is not possible as it would result in an uncomfortable cabin. Nevertheless, through various tiny details, it is possible to influence airflow over the body so that it is smoother and with less turbulence, there is less drag.

The majority of vehicle owners would benefit from the good aerodynamics of their vehicle’s design but those who add on certain accessories may upset the efficiency in a tiny way. Even installing wider wheels and tyres can have a negative impact because these will stick out of the bodywork and create wind resistance.

Adding spoilers, which give the ‘sporty’ look can also have a negative impact. While rear spoilers can provide some downforce to improve stability, this only happens at higher speeds. If you’re driving around town, a spoiler would do nothing but its weight would also be disadvantageous.

A factory-fitted spoiler on a Ford model which was designed with optimum aerodynamic benefits.

The carmakers also provide spoilers on some models but these have been carefully shaped through wind tunnel studies. They have been put there to influence the airflow in a positive way and help to reduce wind resistance. There are also other features such as the almost flush interface between the window glass and the frames which also help lower wind resistance.

So the point here is that the design of your vehicle has already been optimised for good aerodynamics and unless you are going racing, adding other things to the bodywork can worsen aerodynamic efficiency. The effect on fuel consumption may be very small but over the longer term, it still adds up.

[Chips Yap]

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