Introduction

1. fuel blends (such as E10 or B20 where fuels are physically mixed), and
2. dual fuel technologies (where the fuels are not mixed and introduced into the engine separately).

Dual-fuel technology has existed since the very beginnings of engine development with Rudolph Diesel (1901).

A method and arrangement of supplying a supplementary fuel (8) to a compression ignition internal combustion engine wherein an air supply (3) to the engine is first caused to pass through a natural vortex creator (1), and a supply of supplementary fuel (8) to the engine is supplied into a low pressure area the natural vortex (1) which provides a substantially constant ratio of supplementary fuel to main fuel through varying load conditions.

Our studies aim at:

• Developing a fundamental understanding of the combustion of dual-fuel engines.
• Investigating the fundamental processes underlying ultrafine particle formation in dual fuel engines.
• Developing quantitative understanding of the influence of different engine parameters and  fuel/water ratio on (a) the performance and (b) emissions of a dual fuel engine.
• Optimising dual fuel engine performance for methanol/ethanol blend fuels.

To achieve this purpose, the group will undertake a two pronged investigation.

1. The fundamental operation of a dual fuel compression ignition engine.
   Compression ignition (Diesel) engines dominate the heavy transport sector as well as stationary energy generation. They are the most efficient of all reciprocating internal combustion engines. In a dual fuel engine the primary fuel is mixed with air in the intake manifold before it inducted into the cylinder. The mixture is then compressed in the cylinder and a pilot quantity of diesel fuel is injected to initiate combustion. The combustion processes of dual fuel engines lie between that of the compression ignition and spark ignition engines fuel results in further increases in ignition delay, compared to the pure diesel condition (Lee et al. 2003). Thus use of dual fuels enables a potentially improved ability to control the combustion characteristics and ultimately the performance of the compression ignition engine.
   
2. Characterisation of gaseous/particulate emissions from dual fuel compression ignition engines.
   While emissions from motor vehicles operating on any type of fuel contribute to elevated concentration of airborne pollutants, emissions from compression ignition engines are considered to be of particular significance. It has been reported that emission levels of particles could be significantly higher from compression ignition than from spark ignition engines, both in terms of mass and particle number. Although some work has been published on the emissions of regulated pollutants from dual fuel engines only one reference so far by this group (Ristovski et al 2006) has considered aspects of ultrafine particle emissions. This work has shown that ultrafine particle emissions are reduced in LPG/Diesel dual-fuel engines at the expense of increased emissions of unburned hydrocarbons and carbon monoxide. A reduction in the most important greenhouse gas, CO2, was also observed. Further work is needed in better understanding the fundamental processes underlying ultrafine particle formation in a complex system such as in dual fuel engines.