Fuels in Transportation - Decreasing Fuel Consumption and Exhaust Gas Emissions in Transportation - page 15

Table 2.2 Characteristics of petrol

Parameters Physical and chemical characteristics

Type of fuel The most important types in road mobility are normal and super fuels. Super

fuels have a lower knocking characteristic in high compression engines
than normal fuels. In addition, the volatility is different in normal and
super fuels which influence summer and winter applications in regions

Density In Europe, the permitted density range for gasoline fuels is limited to

720-775 kg m -3 (44.94-48.44 lb ft -3 ) in the EN 228. Super fuels have
a higher density than normal fuels and also an insignificantly higher
heating value because of the generally higher concentration of aromatic
hydrocarbons

Octane number The octane number indicates the anti-knocking characteristic of petrol. If

the octane number is higher, there are more anti-knocking substances in
the fuel. The octane number can be characterized by the research octane
number (RON) and the motor octane number (MON)

Additives Additions of components containing oxygen, e.g., methanol, ethanol, methyl

tertiary butyl ether beneficially increase the octane number, but can lead
to other difficulties. Problems can arise because alcohols increase the
volatility and can attack the internal material of tubes, pipes, and tanks

Volatility To ensure optimal road performance, volatile components must provide an

optimal cold start, but high volatility must not lead to problems either in
the hot start or in the ''vapor lock'' at higher temperatures. In addition,
the evaporation losses must be kept low in order to protect the
environment

Vapor pressure In Europe, the vapor pressure of fuels is measured at 38C (100F)

according to EN 13016-1. Gas bubbles at temperatures between 80 and
100C (176 and 212F) can lead to disturbances while driving.
Therefore, the steam pressure is limited in all specifications, e.g., in
Germany in the summer at a maximum of 60 kPa (1,253.1 lbf ft -2 ) and
in the winter at a maximum of 90 kPa (1,879.7 lbf ft -2 )

Sulfur content Sulfur lubricates mechanical parts inside the engine. It burns to SO 2 and

produces acids which are dangerous to human health and the
environment. In the future, the sulfur content of fuels must be further
reduced. A worldwide content of less than 10 ppm is desirable

Anti-aging
protective
substances

Anti-aging protective substances or deactivators increase the storage
stability of fuels through the use of crack components. They prevent the
oxidation of fuels and stop the catalytic influence of metal ions

Water Water must not be contained in the fuel because it can destroy the entire

injection system, starting with the injection valves

2.2.2 Diesel Fuel

Diesel fuels consist of single hydrocarbon components, which boil between 180
and 370C (356 and 698F). They are produced through the gradual distillation of
crude oil. The refineries also add conversion products, e.g., crack components to
the diesel fuel in increasing volume, which are obtained from heavy oils by
splitting the long molecules [ 11 ].