Benefits of/T GDI Engines and their unique engine oil requirements

Benefits of/T GDI Engines and their unique engine oil requirements

Feb 16, 2018

Topics: Passenger Cars

Automakers are making the shift.

Over the past decade, you’ve undoubtedly noticed a significant shift in the market to T/GDI (gas direct injection and turbo gas direct injection) engines. Per IHS, the leading source for U.S. automotive registration data, in 2016 there were 25.5 million registered passenger cars in the United States powered by this innovative engine technology. As astonishing as that number is, the wave is just getting started. In fact, IHS predicts that by the year 2024, 8 out of 10 cars produced in America will be equipped with T/GDI engines.

What's driving the change?

To meet challenging regulatory requirements as well as consumer demand for greater efficiency and better performance, more and more automakers have been opting for these smaller, lighter T/GDI engines. Their performance characteristics are indeed impressive, with a 4-cylinder T/GDI engine able to generate the same levels of torque as its 6-cylinder port fuel injected (PFI) counterpart. However, all that power comes at a price: a much harsher engine environment. In fact, the word harsh may not be harsh enough considering the brutal conditions created by greater cylinder pressure, slower operating speeds and higher sustained temperatures when compared to PFI engines.

To accomplish greater power and compression ratios, these downsized engines operate by spraying fuel directly into the engine cylinder, providing a cooling effect. The cooling effect allows the engine to produce increased compression ratios and more torque, resulting in greater fuel efficiency. Automakers have further combined turbochargers with gas direct injection engines (putting the T in T/GDI) to recover energy that is otherwise lost through exhaust systems to achieve even greater fuel efficiency.

Alongside these dramatic changes in engine design, the industry is witnessing similar leaps forward in engine oil technology to help realize the full benefits of T/GDI engines and to contribute to greater fuel economy. “This is accomplished with new engine oil additive technology developed specifically for the harsh operating conditions and unique performance requirements of T/GDI engines,” according to Gabe Rhoads, the Global Passenger Car Business Manager for Lubrizol. “Today's new lower viscosity and higher performing engine oils rely on advanced additive chemistry to enable T/GDI engines without sacrificing the oils’ fundamental ability to clean and protect.”

Harsher environment demands more from an engine oil.

While a T/GDI engine creates tremendous power more efficiently, it also can create potentially detrimental conditions. First, there’s the issue of increased soot and fuel dilution due to changes in injection and combustion. This new form of soot in T/GDI engines can cause a rapid viscosity increase in the oil, while the change in injection can increase fuel dilution which can accelerate wear. These more demanding conditions require higher performing lubricants with better cleaning and antiwear properties, as well as improved oxidation control.

Accelerated chain wear is another common problem brought about by the unique conditions of a T/GDI engine. While some wear to the timing chain is normal over time, it can occur much more rapidly and prematurely in T/GDI engines without an engine oils specifically engineered to prevent it.

While these T/GDI engine issues are certainly noteworthy, currently the most important issue is LSPI, or low speed pre-ignition. With its higher in-cylinder pressures, together with slow operating speeds, a T/GDI engine creates an environment where uncontrolled combustion (or LSPI) is more likely to occur prior to the air/fuel mixture being ignited by the spark plug. Rhoads notes, “Vehicle owners are experiencing everything from what seems like traditional engine “knock” (damage from which often adds up over time) to sudden engine failure – a single catastrophic combustion event that leaves the vehicle stranded on the roadside and in need of a new engine.” There’s a high degree of unpredictability with LSPI.“In many cases,” warns Rhoads, “there’s no warning at all before a catastrophic event.”

The right oil is required.

These issues are very real and are impacting T/GDI engine performance every day in vehicles from coast to coast. As widespread as the problem is, the awareness level among motorists is low. Fortunately, a proven solution also exists. “We worked closely with OEMs to develop additive technology specifically to minimize LSPI and premature chain wear,” says Rhoads. “One of the hallmark features of this new technology is proven LSPI protection throughout the oil drain interval, an attribute that will be appealing to consumers.”

To make it easier for consumers to select engine oils designed specifically for use with T/GDI engines, the industry recently approved a new SN PLUS category. Consumers should expect products that meet this new category to be available sometime in 2018. “Anyone who has a vehicle with a T/GDI can drive with a much greater sense of confidence by using only SN PLUS engine oils,” says Rhoads. “Consumers are also likely to see higher retail and service shop prices for these engine oils engineered specifically to address the challenging operating conditions of T/GDI engines.”

These days, running the right fluids in the right engines is more important than ever. “The negative impact of operating a T/GDI engine with the wrong oil, as seen with LSPI, can be far worse than merely paying a few more dollars for an oil change,” concludes Rhoads. “If it’s a T/GDI engine, make sure your lubricant has that SN PLUS designation on the label as soon as it becomes available.”

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