Real-Time Observations of the Effect of Fuel Dilution in an Engine Transient Friction Rig. Along with Real-Time Observations of Fuel Entering and Leaving Internal Combustion Engine Oil, over both Standard Engine, ICE and Hybrid, HEV Dynamic Drive Cycles.

Hybrid electric vehicles with an increasing level of electrification, are becoming a major part of the global energy transition. To achieve lower engine tailpipe exhaust emissions and improve total fuel consumption, typically the hybrid electric vehicle (HEV) control system efficiently and frequently switches between the internal combustion engine and electric motor drive, with multiple stops and restarts of the internal combustion engine. A consequential result of this switching is typically slower, or even incomplete engine warm up times, depending on the engine speed, load pattern and run time of the vehicle drive cycle. Along with the speed and load transient control, the engine stop and start processes are also challenging to control, with respect to cold start fuel and combustion by-products entering the oil. Consequently, contamination enters the engine oil but may not completely leave. These effects are highly transient over the drive cycle with contaminants, in particular fuel dilution, affecting the engine oil viscosity. To demonstrate this whilst yielding insights, a precisely controlled engine test cell, running the cold start Worldwide Harmonized Light Duty Transient Cycle (WLTC) for both, unhybridized internally combustion engine (ICE) and HEV in charge sustaining mode operation is described. This also has on-line viscosity sensing and oil sampling. Typical data is shared along with some engine oil comparisons. For complimentary insights, the impact of the fuel dilution on engine friction was investigated using a novel, precise, fully transient engine friction test rig, which measures gasoline direct injection (GDI) high pressure (HP) fuel pump friction and oil viscosity accurately. The cycle is based on measured data from vehicles tested on a chassis dynamometer. On-line friction data, with oil comparisons is used to show real-time, the effect of fuel dilution on the frictional energy required, thus lubricant related CO2 emission effects over the full WLTC.