MOTUL

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Hydrodynamic
Lubrication

Boundary
Lubrication

Ad Molecule Film

ESTER OIL

Under normal conditions, oil forms a continuous film between two surfaces. This oil film provides hydrodynamic lubrication as it prevents direct metal-to-metal contact thereby reducing friction.

The ability to maintain a continuous layer of oil between two metal surfaces is an important attribute of an engine oil to provide fluid lubricity. Friction and wear result when this lubricant film is broken under high load conditions. This is where Esters excel in providing boundary lubrication. Ester has the propensity to reduce friction where other base oils fail.

Ester's molecules: consist of Oxygen (O), which has a positive polarity, and Hydrogen (H), which has a negative polarity. These two molecules electrically adsorb onto the metal surfaces and form a layer known as ad molecule film. It is this ad molecule film that makes Esters stand out from other oils (where film is created by viscosity).

The difference is obvious in its lubrication performance when starting the engine. With oils that depend on viscosity for film strength, pressure and oil will drop when the engine stops. When the engine is restarted, the film between the two metals no longer exists and this results to a dry start. Ad molecule film on the other hand, does not rely on viscosity for fluid lubrication. Therefore it is able to continuously lubricate between the two metals even if the engine stops.

In city driving, where there are frequent start and stop, these car engines are subjected to more stress than in racing. It is therefore more critical that the appropriate engine oil is chosen to protect car engines.

MOTUL uses Ester as base oil for its 4-stroke and 2-stroke engine oils.



	Comparison Chart

ESTER AS BASE OIL FOR SYNTHETIC OIL

Before the introduction of Esters, the choice of base oils was based on its ability to control viscosity. It was thought then, that the thicker the oil the better it would be.

By employing Esters as the base for synthetic oil, MOTUL changed the conventional concept of synthetic lubricants. Esters are polar molecules that have the ability to electro-chemically bond with metals, so as to maintain a continuous lubricant film at high or low temperatures.

After experimenting with a variety of Esters, MOTUL selected Complex Esters in 1996 as its latest generation of base oils. Complex Esters have increased adsorption ability thereby making higher performance synthetic oils.

Diester (introduced in 1973)

Neopoly • Ester

Complex Ester