Oil for hybrid cars

The requirements for the oils differ only slightly or not at all from common lubricants. This is because even the diesel or gasoline engines installed in hybrid vehicles are only combustion engines for which the manufacturers provide exact specifications. These are decisive for the lubricant development at ADDINOL. Many oils with approvals for cars with combustion engines are therefore also approved for hybrids.

Since combustion engines in hybrid cars do not run permanently, depending on their design, the operating temperature of the engine may not be as high as in conventional combustion operation. Switching from the electric engine to the combustion engine depending on the driving profile is therefore comparable to an increased number of engine cold starts. In these cases, it is important that the engine oil has excellent temperature-viscosity properties in order to be able to protect against wear and corrosion at the critical lubrication points quickly enough even in cold condition. For this reason, we mainly recommend oils with a cooling character of 0W or 5W and viscosity layers with a smooth-running character of SAE 30, 20 or even lower depending on the manufacturer's specifications.

On the transmission side, hybrid cars rely almost exclusively on automatic transmissions. In terms of overall efficiency, these are now in no way inferior to manual transmissions. At the same time, they offer the necessary automation to make switching between the electric engine and the combustion engine almost imperceptible to the driver. In addition, the electric drive unit between the combustor and the drive train can be optimally integrated into it from an engineering perspective.

However, this is where the source of new challenges for the development of suitable transmission oils lies. During acceleration, but especially during brake energy recuperation, a great deal of energy is fed into the electric engine, which operates as a generator. This generates a lot of heat because the battery chemistry is not fast enough to use everything for charging. With the proximity of the electric drive unit to the gearbox housing, a strong heat input is then generated. This increases the temperature stress up to 180°C. Only modern high-performance additive technologies and high-quality base oils offer very good resistance to such high thermal loads on the automatic transmission fluid. For this reason, we only recommend the products of our latest generation of the ATF XN series.