Cold-Cranking Simulator Apparent Viscosity

Description

Simulates the conditions of engine crankshaft cranking by the starter in extreme cold, ensuring easy starting and the absence of increased wear in the first seconds of operation.

About 80% of the wear in a modern engine occurs precisely at the moment of cold starting, when oil from the sump has not yet reached all friction nodes. If on a freezing morning the starter cannot crank the crankshaft, the overly high dynamic viscosity (CCS) of the motor oil is to blame. The RENA laboratory uses a high-tech Cold-Cranking Simulator to give you 100% confidence that your 0W, 5W, or 10W grade oil will ensure safe and easy starting of the unit even in extreme cold. This test is the absolute certification foundation for the production of any multigrade motor oil. The complex test according to the ASTM D5293 method is performed on a unique CCS instrument. A sample of the test oil is injected via syringe into the micron gap between the stator and rotor. This assembly is lightning-fast cooled by powerful Peltier elements to critical temperatures from -10 °C to -35 °C (depending on the tested SAE winter viscosity grade). After reaching the set sub-zero temperature, the rotor is driven by a DC electric motor. The instrument automatically measures the rotational speed of the rotor, which is directly proportional to the resistance (viscous friction) exerted by the thickened cooled oil: the thicker the fluid, the slower the rotor turns. The dependence of speed on viscosity is pre-calibrated in the laboratory using a series of Newtonian reference fluids. As a result, the instrument calculates the apparent dynamic viscosity in millipascal-seconds (mPa·s). This figure correlates perfectly with the resistance experienced by a real automotive engine from frozen oil while the crankshaft is being cranked by the starter.