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This paper describes the results of a series of tests on a heavy-duty truck diesel engine using conventional and low viscosity lubricants. The objectives were to explore the impact of reducing lubricant viscosity on wear, friction and fuel consumption. The radiotracing Thin Layer Activation method was used to make on-line measurements of wear at the cylinder liner, top piston ring, connecting rod small end bush and intake cam lobe. The engine was operated under a wide range of conditions (load, speed and temperature) and with lubricants of several different viscosity grades. Results indicate the relationship between lubricant viscosity and wear at four critical locations. Wear at other locations was assessed by analysis of wear metals and post test inspection. The fuel consumption was then measured on the same engine with the same lubricants. Results indicate the relationship between oil viscosity and fuel consumption under a wide range of operating conditions.

An increase in global oil consumption, coupled with a peak in oil production, has seen the price of fuel escalate in recent years, and consequently the transport sector must take measures to reduce fuel consumption in vehicles. Similarly, ever-tightening emissions legislation is forcing automotive manufacturers to invest in technology to reduce toxic emissions. In response to these concerns, this project aims to address one of the fundamental issues with the Internal Combustion Engine - approximately one third of the fuel energy supplied to the engine is lost as heat through the exhaust system. The specific aim of this project is to reduce the fuel consumption of a diesel-electric hybrid bus by recovering some of this waste heat and converting it to useful power. This report details how turbocompounding can be applied to the engine, via the inclusion of a turbogenerator, and assesses its waste heat recovery performance.

In any internal combustion engine, the amount of heat rejected from the engine, and associated systems, is a result of the engine inefficiency. Successfully recovering a small proportion of this energy would therefore substantially improve the fuel economy. The Rankine Cycle system has been raising interest for its aptitude to produce systems capable of capturing part of this waste heat and regenerate it as electrical or mechanical power. By integrating these systems into existing hybrid engine environments, it has been proved that Rankine Cycle system, which is more than 150 years old, can play a major role in reducing fuel consumption. The use of such a system for waste heat recovery on a hybrid engine represents a promising compromise in transforming the thermal energy into electricity and feeding this electricity back to the vehicle drivetrain by using the in situ electrical motor system or storing it into batteries.

Diesel fuel injection pressures have increased steadily on heavy duty engines over the last twenty years and pressures as high as 300MPa are now possible. This was driven by the need to control toxic exhaust emissions, in particular particulate emissions using advanced in-cylinder combustion strategies. With the introduction of efficient aftertreatment systems for both particulate and NOx emissions control there is less demand for in-cylinder emissions control especially considering the drive for improved fuel economy. In this paper we consider the benefit of high fuel injection pressure for a number of emissions control strategies with different balances of in-cylinder and exhaust aftertreatment emissions control. A test program was undertaken on a single cylinder heavy duty research engine installed at the University of Brighton, in collaboration with Ricardo.

The recuperated split cycle engine is a fundamentally new class of internal combustion engine that offers a step change in thermal efficiency over conventional Otto and Diesel cycle engines. In a split cycle engine, the compression and combustion strokes are performed in different cylinders. Intensive cooling of the compression stroke by the injection of liquid nitrogen directly into the chamber enables the recovery of waste heat from the exhaust between the compression and combustion cylinders. Brake efficiencies of over 50% have been reported without compression cooling, rising to 60% where the compression stroke is cooled by the injection of liquid nitrogen. The technology targets the heavy duty, long-haul sector where electrification is ineffective. In this paper, results from an experimental program conducted on a single cylinder research engine, representing the combustor cylinder of a recuperated split cycle engine are reported.

Concerns over the impact of road transport emissions on the climate have led to increased focus on how CO2 emissions could be reduced from the sector. This is of particular concern in the commercial vehicle sector, where engine downsizing and electrification have limited benefit due to the vehicle duty cycle. In this paper, we present results from an experimental program to investigate the impact of dual fueling a heavy duty engine on hydrogen and diesel. Hydrogen is potentially a zero carbon fuel, if manufactured from renewable energy but could also be manufactured on the vehicle through steam reformation of part of the liquid fuel. This opens a novel pathway for the recovery of waste heat from the exhaust system through the endothermic steam reformation process, improving the overall system efficiency. For these concepts to be viable, it is essential the dual fueled combustion system is both thermally efficient, and does not increase toxic emissions such as NOx.

Practical direct injection hydrogen combustion applications typically require operating the engine in the lean regime. Lean hydrogen flames feature strong thermo-diffusive instability effects making 3D CFD simulations challenging. In particular where the calibrated model is required to operate across a range of equivalence ratios without adjustment and provide accurate results on coarse grids necessitated by the run-times of 3D CFD. In this paper we present a 3D CFD study of a Euro VI HD diesel engine converted to operate on hydrogen gas using direct injection. A scaling methodology recently proposed for conversion from constrained to freely propagating flame based on DNS data is implemented. A laminar flame speed tabulation is developed based on the conversion of 1D results obtained from direct kinetics simulations to freely propagating flame expression considering the behaviour of the thermo-diffusive instability for a wide range of pressures, temperatures and equivalence ratios.