Mitigating the harmful effects of GDI contaminants is complicated by numerous global factors — but lubricants can help reduce the risk

It’s a familiar story — global legislative regulation has spurred car makers’ continued pursuit of CO₂ reductions and fuel efficiency. These forces have led OEMs to utilize gasoline direct injection (GDI) and turbocharged GDI (TGDI) engine technology in developing more efficient and cleaner-running passenger cars.

However, contaminants specific to GDI/TGDI engines and their associated challenges have had a stifling effect on the technology. These contaminants can interfere with a lubricant, reducing its effectiveness and protective capabilities. Contamination by GDI soot, a carbonaceous contaminant produced in rich spots of incomplete combustion, can lead to accelerated wear throughout the engine, particularly the engine’s timing chain.

With significant investment in GDI/TGDI technology around the globe, controlling the effects of these contaminants is critical. It’s believed that with advanced additive chemistry, lubricant formulations can mitigate the wear caused by GDI contaminants providing optimal operation of GDI engines everywhere.

Differing global design approaches to GDI/TGDI technology complicate the development of a single mechanical solution to GDI contaminants. For instance, the European passenger car market was first to adopt GDI/TGDI technology, making these engines roughly a generation ahead of those proliferating in other markets. This is primarily due to Europe’s strict CO₂ regulations; GDI/TGDI allowed OEMs to develop smaller, turbocharged engines that reduced emissions without sacrificing performance. Following OEM-specific guidelines, the ACEA oil sequences will become more reflective of GDI/TGDI technology.

From Europe, the technology grew as legislation in other regions similarly called for emissions reductions. But the tests measuring those reductions vary depending on the market. The new European drive cycle (NEDC) test for CO₂, used in Europe and China, differs from the federal test procedure (FTP) in the USA, spurring varying approaches to engine design and calibration for CO₂ reduction. Combined with varying engineering and design sophistication among GDI engines in these markets, a reliable turnkey solution has been elusive.

The fundamental issue of GDI contaminants is not uniform. GDI technology applied on a broad scale is still very new for all stakeholders; research into GDI contaminants, their effects and possible remedies remains ongoing. Independent work by the Lubrizol Corporation indicates the possibility of contaminant production being heavily dependent on operating conditions. If this is the case, field trials may be a necessary addition to standard industry engine tests. Furthermore, fuel quality can impact GDI contaminants, with lower-quality fuel leading to greater lubricant dilution and sludge production. Given that fuel quality differs across the globe, it’s another obstacle for stakeholders in solving the issue.

Approaches to minimizing wear from GDI contaminants differ. Some prefer an engineered solution; others look to the lubricant. The best solution will likely be a combination.

One thing is clear: with international differences in engine design and testing methods, the lubricant’s job — mitigating the effects of GDI contaminants and deposits to maintain robust engine protection — remains constant and critical. Lubrication technology can’t change the way an engine operates, the fuel quality an engine receives, or the combustion process responsible for the generation of contaminants. But it can reduce the risk of issues associated with those contaminants, enabling the engine to continue operating as originally designed.

Testing and research beyond industry-standard procedures have enabled Lubrizol to pursue a lubricant additive solution. Lubrizol’s collaboration with OEMs has formed an enhanced understanding of GDI contaminants, and enables the development of lubricant-related solutions concurrently with hardware solutions. Contact your Lubrizol Account Manager for further information.

Article courtesy of Engine Technology International — September 2015