Synthetics in HDEO have been around for a while - Rotella T6 is a prime example - mostly focused on grades like 5W40 and 5W30. This is a really interesting perspective on hardware changes that are co-engineered with lower engine oil viscosity in mind:
Originally Posted By: From the Article
In 1993, when Volvo introduced its current baseline on-road truck engines, the D12/D13 platform, they used a 15W-40 engine oil with high temperature, high shear rating (HTHS) of 4.2 centiPoise. The engines had a fixed oil pump without a relief valve, no oil thermostat and relief valves that helped cool pistons. Oil operating temperatures were 95 degrees C.
Since then, engine sizes were reduced to improve fuel economy, reducing oil sump volumes. This caused oil operating temperatures to rise enough that OEMs had to monitor and manage the temperature. When oil temperatures reached 105 degrees, Volvo installed wax thermostats, and when they reached 118 degrees, the company switched to electrical thermostats.
Engine manufacturers also began to install components such as exhaust gas recirculation valves and crankcase ventilation oil separator valves and oil filter bypass valves, which require fluid pressure provided by the engine oil. Increasing the number of oil-consuming components reduced oil pressure and oil flow.
To reduce engine friction (in the interest of improving fuel economy), engine manufacturers began recommending thinner oils, and Volvo now recommends a 10W-30 with HTHS of 3.5 cP for its baseline engines. It still uses a fixed oil pump, but that pump now has a relief valve. The piston relief valves have been replaced by electrically powered relief valves. Today’s oils allow a 2 percent improvement in fuel economy compared to those used in 1993.
State-of-the-art heavy-duty engines will soon employ variable displacement oil pumps and use 0W-20 engine oils with HTHS of 2.9 cP. Compared to the oils used today, these lubricants will enable fuel economy to improve an additional 1.5 to 2 percent.
Lube Report
BRING ON THE FA-4
Originally Posted By: From the Article
In 1993, when Volvo introduced its current baseline on-road truck engines, the D12/D13 platform, they used a 15W-40 engine oil with high temperature, high shear rating (HTHS) of 4.2 centiPoise. The engines had a fixed oil pump without a relief valve, no oil thermostat and relief valves that helped cool pistons. Oil operating temperatures were 95 degrees C.
Since then, engine sizes were reduced to improve fuel economy, reducing oil sump volumes. This caused oil operating temperatures to rise enough that OEMs had to monitor and manage the temperature. When oil temperatures reached 105 degrees, Volvo installed wax thermostats, and when they reached 118 degrees, the company switched to electrical thermostats.
Engine manufacturers also began to install components such as exhaust gas recirculation valves and crankcase ventilation oil separator valves and oil filter bypass valves, which require fluid pressure provided by the engine oil. Increasing the number of oil-consuming components reduced oil pressure and oil flow.
To reduce engine friction (in the interest of improving fuel economy), engine manufacturers began recommending thinner oils, and Volvo now recommends a 10W-30 with HTHS of 3.5 cP for its baseline engines. It still uses a fixed oil pump, but that pump now has a relief valve. The piston relief valves have been replaced by electrically powered relief valves. Today’s oils allow a 2 percent improvement in fuel economy compared to those used in 1993.
State-of-the-art heavy-duty engines will soon employ variable displacement oil pumps and use 0W-20 engine oils with HTHS of 2.9 cP. Compared to the oils used today, these lubricants will enable fuel economy to improve an additional 1.5 to 2 percent.
Lube Report
BRING ON THE FA-4