F+L Week 2018 | Keith Howard | The Evolving Fuel and Lubricant Challenges of GDI Engines in China
Gasoline direct injection (GDI) engines and their turbocharged versions (TGDI) offer an attractive solution for manufacturers wanting compact, powerful and economical power units for their cars. With a growing number of larger, heavier cars in the China market and with fuel economy legislation tightening year-on-year, they are becoming increasingly popular and will power the majority of China’s cars within the next few years. For several years they have been known to pose some unique challenges to the fuels and lubricants used. These challenges include:
- High power density leading to increased operating temperatures and faster oil oxidation
- Increased levels of fuel dilution leading to loss of viscosity and oil degradation
- Aggressive wear of certain engine components (such as timing chains)
- Potential for low speed pre-ignition (LSPI) leading to catastrophic engine damage
- Loss of performance and increased emissions due to injector deposits
More recently the emissions performance of these engines has come under increasing scrutiny as the government moves towards implementation of China 6 legislation. Due to the nature of direct injection, GDI and TGDI engines emit high levels of ultrafine particulates and may exceed China 6 particulate number (PN) limits. Gasoline particulate filters (GPFs) are being adopted by many OEMs as the key technology to ensure compliance with regulations. This brings the new dimension of GPF compatibility to the challenge, requiring a special approach to formulating the engine lubricant. The adoption of GPFs by many OEMs has brought the dimension of aftertreatment compatibility to engine oils for China’s TGDI powered cars. Ash blocking of the filter and reduction in catalyst efficiency are added concerns and ones which additive companies are addressing with engine oil formulations. Data will be presented from studies done in Lubrizol’s engine test laboratories, and from field trials in China, to show the benefits of aftertreatment compatible formulations on the performance and durability of the GPF. This presentation will outline the nature of these challenges and will describe how the right approach to formulating the lubricant will provide excellent protection, enhance efficiency and maintain low emission levels over a long vehicle lifetime. It will also include unique fuel additive solutions for the prevention and removal of injector deposits, enabling optimum combustion and contributing further to the engine’s clean, reliable operation over many years.