Gas car engine oil lubricants manufacturers characteristics?

Compressed natural gas CNG, LPG liquefied petroleum gas as a clean fuel use has increased every year, the gas engine lubrication with gasoline and diesel engines are similar, but changing the structure of the fuel and the engine, and working conditions, changes in the material, the use of CNG and LPG-fueled cars not to use regular gasoline engine oil or diesel oil, which is due to the following reasons: (1) high temperature combustion cars will increase NOx generation; (2) Gas fuel contains no sulfur, moisture, oil requires the use of ash-free or low-ash type, ash content is too high will cause the engine pre-ignition and spark plug plug; (3) the combustion temperature, increasing the engine heat load requirements of the oil temperature and better oxidation stability; (4) the compressed gas without lubrication, easily lead intake valve, exhaust valve seat wear, abrasion resistance requirements of the oil better.