Piston cleanliness is critical in vehicle engines, regardless of their age. Clean pistons generate minimal levels of wear, provide a smooth operating engine, keep emission levels low as well as staying within the fuel efficiency parameters set by the original equipment manufacturer (OEM). In contrast, poor piston cleanliness and deposit build up can lead to stuck piston rings resulting in poor inefficient combustion and increased levels of wear within the engine and ultimately costly engine failure.
The CEC L-117-20 piston cleanliness test is a key diesel lubricant performance test within the latest ACEA Light-Duty Engine Oil Sequences upgrade. Applicable across all A/B “High SAPS” and C “Lower SAPS” categories, it is commonly referred to as the “TDI3” test. The TDI3 test has been introduced into the ACEA 2021 Light-Duty Engine Oil Sequences to replace the TDI2 test, formally called CEC L-078-99 and first introduced over 20 years ago. The TDI3 test replaces aging Volkswagen (VW) hardware with a more modern engine, ensuring lubricant performance continues to protect current diesel engines. The TDI3 test utilizes a 2.0 liter VW EA288 Euro 6 engine incorporating modern features of dual Exhaust Gas Recirculation (EGR), Variable Geometry Turbocharger (VGT), Nitrogen Oxides (NOx) catalyst and Diesel Particulate Filter (DPF). As the engine used in the TDI3 test is significantly more powerful than the hardware used in the TDI2 test, the engine lubricant must demonstrate strong performance in hotter and more severe operating conditions. Lasting a total of 42 hours with oil sump temperatures at a sustained 145°C oil temperature, the TDI3 test uses a high sulphur diesel fuel and protects against a future scenario where increased soot levels are derived from the wide usage of EGR . Overall piston cleanliness and ring sticking are measured with key rating areas including the piston lands and piston grooves.
As the TDI3 is a replacement test within ACEA 2021, it is a requirement that the test is equal in severity to the outgoing TDI2 test. Given the modern engine hardware used in the TDI3 test is operating in more severe and hotter conditions, the limits set within the TDI3 test are adjusted to ensure they remain comparable in severity to the test it is replacing.
Engine lubricants meeting the robust TDI3 piston cleanliness test have to be correctly formulated to ensure they deliver the performance and protection demanded for today’s modern and high-powered diesel engines.
For more information on the ACEA 2021 upgrade for light-duty engines, please contact your Lubrizol representative.