Improvements relating to fuel economy

Abstract

The present invention relates to the use of a viscosity increasing component in a diesel fuel composition, for the purpose of improving the fuel economy of an engine into which the fuel composition is or is intended to be introduced, or of a vehicle powered by such an engine, wherein the viscosity increasing component is a viscosity index (VI) improving additive, the VI improving additive comprises a linear block copolymer, which contains one or more monomer blocks selected from ethylene, propylene, butylene, butadiene, isoprene and styrene monomers, and the VI improving additive is used at a concentration of from 0.001% w / w to 0.05% w / w.

Description

technical field [0001] The present invention relates to a method of improving diesel fuel economy in a compression ignition (diesel) engine; and in particular to the use of a viscosity increasing component in a diesel fuel composition for improving fuel economy. Background technique [0002] For example, current emissions regulations in the United States and Europe set strict limits on acceptable levels of polluting gases to be tolerated in the exhaust emissions of compression ignition engines. [0003] A typical approach taken by engine and fuel manufacturers to improve the combustion process and reduce the generation of undesired exhaust emissions is to utilize some form of "pre-combustion". Pre-combustion is an umbrella term covering many different combustion modes that typically involve one or more of the following features: fuel injection well ahead of top dead center (TDC); multiple fuel injections; extensive exhaust gas recirculation ( EGR); and high injection pressu...

AI Technical Summary

Problems solved by technology

This variation in the properties of certain fuels means that the type of fuel actually used in a particular engine can have a significant impact

[0009] Additionally, since the amount of fuel injected into a vehicle's engine is primarily governed by volume, a reduction in fuel density results in a reduction in the amount of combustible fuel in the engine's cylinders, resulting in a reduction in the effective amount of energy that can be converted

This further drives the engine's emissions in the direction of low NOx and high PM, but is detrimental to engine efficiency and increases fuel consumption

While there may be a slight benefit in terms of NOx emissions, it is now recognized that this setup does not provide the optimum balance between fuel economy and exhaust emissions that vehicle manufacturers expect

[0010] Given the above operating procedures and issues, it is difficult to achieve an optimal balance between fuel economy and exhaust emissions using only standard refined fuels

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