The Stop/Start system is a technology found in many modern vehicles. Car manufacturers are being pushed to meet ever increasing emission standards and Stop/Start technology helps them to achieve the targets. A large number of vehicle owners, however, are concerned that this feature may be harmful to their engine and they simply switch the system off. The frequent stopping and starting of the engine is the reason for this concern.
Most of us are aware that the Stop/Start system automatically turns the engine off when the car is idling (at traffic lights, in traffic jams, etc.) to reduce fuel consumption and emissions. The engine restarts almost instantly when you lift your foot off the brake or press the accelerator. Unfortunately the technology has downsides too. For some of these the motor oil has to compensate. The drawbacks include increased wear, high static friction and elevated engine temperatures.
The automatic Stop/Start systems in vehicles place much greater demands on the engine oil. The constantly interrupted lubrication and cooling of engine components during shutdown requires superior quality oils that meet certain high performance standards. We will delve into the specific requirements, why they arise and whether special lubricants are indeed required.
Increased Wear
A thin hydrodynamic lubricating film (see OilChat 22) separates moving surfaces during normal engine operation. Each time the engine is stopped, this oil film breaks down and the surfaces come into contact with each other. When the engine is restarted, the components operate in the boundary lubrication regime with increased friction and wear, especially when a substandard oil is used.
Furthermore, high static frictional forces are present in the stationary engine. To overcome the static friction between mating surfaces, high forces are required to get the engine going again. This has a negative influence on the service life of timing chains, starter motors and batteries.
To compensate for these technical hitches motor oil for Stop/Start vehicle operation must provide maximum wear protection and should maintain an extremely tough and durable lubricating film. In addition, the oil needs to contain active chemicals that offer effective wear protection in boundary lubrication conditions.
Increased Temperature
When the Start/Stop electronics cut the engine out, flow of oil also stops. This can have fatal consequences on components subject to high thermal loads, such as the turbocharger. Since it is no longer cooled by circulating oil, the temperature inside the turbocharger increases dramatically. Heat from the extremely hot turbine wheel flows to the shaft and bearings and these components can heat up to temperatures exceeding 300°C. This can lead to oxidation and carbonisation of the oil and increased deposits.
So, do Start/Stop systems require special oils due to the increased engine loads? The answer is a surprising NO.
There is no need for such oils because there are no specific Stop/Start engine oil specifications that determine the suitability of a lubricant. Instead the overall performance credentials of the oil determine relevancy. For example an engine oil that conforms to the industry specifications ACEA A3/B4 and API SN/CF will perform satisfactorily in vehicles with Stop/Start technology. In addition, individual vehicle manufacturers may have their own engine oil specifications (e.g. Mercedes-Benz 229.3, Volkswagen 505.01, etc.) that take into account the requirements of their Stop/Start engines.
Q8 oil formulations meet and exceed the requirements of modern engine oil specifications. Our oils offer the highest possible lubricating film stability and their special wear protection chemistry ensures reduced wear and increased engine life, even under the most adverse conditions. Simply put, Q8 engine oils are so advanced that you do not need any special lubricants for engines with automatic Stop/Star systems. In fact, the high performance lubricants in the Q8 Formula engine oil range have been suitable for the severe requirements of vehicles with Start/Stop systems even before the technology existed.
For more information about the range of Q8 engine oils suitable for Stop/Start operation, phone 011 462 1829, email us at info@bcl.co.za or visit www.bcl.q8oils.co.za.