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Plug-in electric vehicle (PHEV) has a promising prospect to reduce greenhouse gas (GHG) emission and optimize engine operating in high-efficiency region. According to the maximum electric power and all-electric range, PHEVs are divided into two categories, including “all-electric PHEV” and “blended PHEV” and the latter provides a potential for more rational energy distribution because engine participates in vehicle driving during aggressive acceleration not just by motor. However, the frequent use of engine may result in severe emissions especially in low state of charge (SOC) and ahead of catalyst light-off. This study quantitatively investigates the impact of oil viscosity and driving mode (hybrid/conventional) on oil dilution and emissions including particle number (PN).

It is anticipated that worldwide energy demand will approximately double by 2050, whilst at the same time, CO2 emissions need to be halved. Therefore, there is increasing pressure to improve the efficiency of all machines, with great focus on improving the fuel efficiency of passenger cars. The use of downsized, boosted, gasoline engines, can lead to exceptional fuel economy, and on a well-to-wheels basis, can give similar CO2 emissions to electric vehicles (depending, of course, on how the electricity is generated). In this paper, the development of a low weight concept car is reported. The car is equipped with a three-cylinder 0.66 litre gasoline engine, and has achieved over 100 miles per imperial gallon, in real world driving conditions.

A predictive model for estimating the fuel saving of “top tier” engine, axle and transmission lubricants (compared to “mainstream” lubricants), in a heavy duty truck, operating on a realistic driving cycle, is described. Simulations have been performed for different truck weights (10, 20 and 40 tonnes) and it was found that the model predicts percentage fuel economy benefits that are of a similar magnitude to those measured in well controlled field trials1. The model predicts the percentage fuel saving from the engine oil should decrease as the vehicle load increases (which is in agreement with field trial results). The percentage fuel saving from the axle and gearbox oils initially decreases with load and then stays more or less constant. This behaviour is due to the detailed way in which axle and gearbox efficiency varies with speed/load and lubricant type.

We review some of the key tribological issues of relevance to motorsport applications. Tribology is the science of friction and wear, and in a high performance engine, friction and wear are controlled by good component design (e.g. the engine and the transmission) and also by the use of high performance lubricants with the correct physical (and chemical) properties, matched to the machine they are used in. In other words, design of a specific lubricant for specific hardware can lead to optimised performance. (Tribology is also important in the tire-road contact but are not considered here.) The importance of key physical properties of a lubricant is demonstrated with an emphasis on how the choice of the correct lubricant can help to minimize engine friction (and thus increase available power output) whilst protecting against engine wear. Key lubricant parameters discussed in the paper are the viscosity variation of a lubricant with temperature, shear rate and pressure.

The fuel consumption of heavy duty diesel engines is of great importance to fleet operators, since fuel can contribute up to 30% of the operating costs. This paper discusses the differences between fuel economy oils for heavy duty diesel engines and passenger car engines. A simple model is then presented showing how the reduced friction due to the use of fuel economy lubricants (both in the engine and the transmission) can lead to fuel consumption benefits. By including realistic losses due to air resistance and tyre rolling resistance, the model can predict fuel consumption benefits under different speed and load conditions that are in reasonable agreement with the benefits found in carefully controlled field trials.