Engine Oil Temperature Research Articles

The Elastohydrodynamic Friction and Film Forming Properties of Lubricant Base Oils

The stringent and often competing requirements of high fuel economy and low emissions are placing increasing emphasis on the selection of appropriate base oils for modem engine lubricants. Two properties now recognized as important in engine oil design are the elastohydrodynamic (EHD) traction coefficient and the pressure-viscosity coefficient. The former determines the level of friction in high pressure contacts such as cams, while the latter plays a major role in determining the EHD film thickness. Unfortunately, for many fluids there is a broad correlation between the two properties so that a low traction coefficient implies a low pressure viscosity coefficient and thus film thickness. This paper measures the traction and film-forming properties of a wide range of base oil types at realistic engine oil temperatures in order to both explore the extent of this correlation and to determine the dependence of EHD lubricant properties on base oil compositions. Presented as a Society of Tribologists and Lubrication Engineers paper at the World Tribology Congress in London, United Kingdom, September 8–12, 1997

A study of engine oil aeration

Abstract The foaming and aeration properties of crankcase oils were investigated through the observation of foam behavior in the crankcase. Entrained air bubbles in the crankcase oil, that is oil aeration, increased as engine speed and oil temperature increased. This also depended on oil formulation. However, surface foam disappeared in high-speed conditions. It was found that the aeration performance of oils had an effect mainly on the connecting-rod bearing wear under high speed-high temperature engine operating conditions.

Oil film thickness measurement in the middle main bearing of a six-cylinder supercharged 9 litre diesel engine using capacitive transducers

A system for monitoring oil film thickness based on a capacitive measurement technique has been adapted to measure hydrodynamic lubricating oil film thicknesses in the middle main bearing of a heavy-duty diesel engine. Transducers have been developed to suit the extreme conditions in the bearing, with very high and varying pressures created by the lubricating film. Measurements of the film thickness as a function of the crank angle have been performed with a variation of the engine speed, load and oil temperature. The start conditions have also been investigated with the engine turned by hand and by the starter motor. The relative error of the measurement is estimated to ±0.56 μm.

95/02104 BMS helps BT to make the right connections

This study has investigated the influence of injection pressure on combustion characteristics and exhaust emissions of a compression ignition engine. The engine was fueled with gasoline, thus named as gasoline compression ignition (GCI) engine. The single-cylinder diesel engine based on the Hyundai commercial engine was used throughout the experiment. Pure gasoline mixed with 5 percent of biodiesel as lubricity enhancer was injected into the cylinder with varying injection pressure. The injection pressures were set at 600 and 1000 bar while the start of injection and injection duration were altered to control the same equivalent ratio (λ=1). To run at the low speed condition, the engine speed was fixed at 1,200 rpm. In addition, other engine parameters including engine oil, coolant water and intake air temperature, were also controlled in specific range. To understand the combustion characteristics such as heat release rate (HRR), thermal efficiency and burning duration, in-cylinder pressure data collected by means of pressure transducer were analyzed with one-zone thermodynamic model. Also, the exhaust emissions (NOx, THC, and CO were measured as well. The results show that the complete combustion was achieved at the high injection pressure. Combustion stability in terms of lower COV was improved with the increase injection pressure. In addition, the exhaust emission (NOX and THC) were decreased.

Safety Topics

TWO incidents are described, both involving bleed air ducts but in dissimilar aircraft with different engines. One incident concerned a Boeing 747–136 in which at just after the decision speed V1. a loud ‘bang’ was heard followed by severe vibration from all four thrust levers. The take‐off was continued normally and the aircraft rotated normally at Vr and entered the climb. The landing gear was not immediately retracted due to the possibility of burst tyres, however, shortly after the aircraft became airborne the No 4 engine generator failure warning lights illuminated, the engine oil temperature indication decreased off‐scale and the exhaust gas temperature (EGT) also reduced to a low reading. Suspecting an engine failure, the commander ordered the landing gear to be retracted. However, since the No 4 engine N1, N2 and fuel flow indications remained normal, the commander decided not to shut down the engine. As the aircraft climbed through 500 ft, the right wing overhead warning light illuminated. At a safe height the flaps and leading edge devices were retracted, control was transferred to the co‐pilot and the flight engineer, monitored by the commander, completed the wing overheat and single generator inoperative check lists. While these were being completed, Heathrow ATC advised that debris had been found on the runway. The commander decided to return to Heathrow and radio vectors were requested for fuel jettison.