THE chemical problems of engine lubrication associated with wear, detergency, and oxidation stability are discussed by the authors.
A detailed examination is made of the stability of lubricating oils in engines. It was found that the oil rapidly becomes contaminated with solid oil-in-soluble materials that greatly affect its stability toward oxidation: In some cases, the stability after 1000 miles of use may be 1% of that of the fresh oil.
By the addition of pure compounds to the oil, and also by the separation of the components of the oil-insoluble materials, it was determined that the metal salts, particularly the halogen salts, are the effective catalytic materials. Two possible methods for combating these catalysts are mentioned by the authors.
A few experiments are also reported indicating a possible usefulness of these engine catalysts in laboratory oxidation tests.