Investigation into the benefits of reduced oil flows in internal combustion engines

Abstract

The engine lubrication system is a vital element for engine health but causes a parasitic load on the engine which increases the fuel consumption: this load can be reduced by matching the oil flow to lubricating requirements using a variable displacement oil pump (VDOP). In a first stage, two VDOPs were installed on a 2.4L Diesel engine; experiments over the New European Drive cycle (NEDC) showed reductions in fuel consumption of up to 3.4% and up to 5.8% over the urban phase of the cycle. A VDOP was subsequently installed on an instrumented engine capturing over 100 metal and fluid temperatures within the engine structure. This showed that reducing oil flows resulted in lower oil temperature by up to 4 o C during cold start NEDC but 2 hotter cylinder liner temperatures by up to 6 o C. The higher cylinder wall temperatures caused an increase of 3% in NOx emissions but a reduction of 3-5% in CO and Hydrocarbon emissions. Finally an energy flow analysis showed that the VDOP can reduce oil pump energy consumption by 160kJ (32%) but that this led to a 400kJ reduction in friction and accessory work. These findings highlight the need for a systems-level rather than a component-level approach to engine lubrication design to capture key thermal interactions.

Adaptation of a 1-D tool to study transient thermal in turbocharger bearing housing

“…Some of the last tendencies in the automotive industry seeking to reduce the engine fuel consumption and emissions might even generate extra damage in the lubrication system. Such as the case of Start-Stop systems, in which the engine is stopped when it was idle and there was neither oil nor coolant flow in the turbocharger, which might produce oil thermal degradation, and some other effects of reducing oil pumping for improving the engine consumption [19].…”

Evaluation of hot water storage strategy in internal combustion engine on different driving cycles using numerical simulations

“…Giakoumis studied the influence of different oil grades, 32 Cipollone et al assessed the gain behind accelerating the oil warm-up time, 33 as well as Battista et al, 34 and Burke et al investigated the benefits of reduced oil flows. 35 In their works, Will et al warmed the lubricant by using the exhaust gases. 36,37 Energy storage is one of the thermal management strategies that proved its importance within several studies.…”