Gas powered engines and wear
Low levels of duty implemented by some governments across Europe have made methane (natural gas and biogas) an attractive alternative fuel for many operators.
Iveco, Volvo and Scania all now offer mainstream trucks with gas power as production models, and Mercedes-Benz has a gas option in its distribution and municipal ranges. There are also gas buses from Scania and MAN.
Compressed natural gas (CNG) stations are opening in the UK alone at the rate of one a month, while leading supplier Gasrec saw supplied volumes of CNG and LNG grow by 286 and 393 per cent respectively in the first half of 2019. By 2027, it estimates, one-third of the UK’s heavy truck parc will be gas-powered.
As an inherently cleaner-burning fuel with little in the way of carbon particulates, operators might expect gas engines to be relatively undemanding of their lubricant.
But gas does provide some unique challenges for lubricants. Consequently, leading engine manufacturers have published oil performance standards for GNG/LNG engines that meet their special characteristics. For example: combustion temperatures are higher than for diesel, putting more stress on the lubricant, and reducing its life.
As with any engine, a small quantity of lubricant finds its way past the piston rings of a gas engine and is subject to combustion. If the wrong type of oil is used, the high combustion temperature will produce a very fine ash, which cannot be removed by filtration but will cause bore and ring polish and valve-seat recession, leading to consequential losses in compression and oil control, foul spark-plugs, and degrade the exhaust catalysts.
So, the lubricant needs to be formulated using a high-quality base oil able to resist the increased thermal load, and a low-ash anti-wear additive package that will protect the engine’s key components without the accumulation of harmful fine ash deposits. Such qualities are found in the Texaco Delo range.
It follows then, that any company introducing gas trucks to its fleet should understand that these vehicles require specialist engine lubricants, and make sure that staff and maintenance providers are briefed accordingly.