Future Transportation Systems - Decreasing Fuel Consumption and Exhaust Gas Emissions in Transportation - page 259

sustainable production low taxes

wordwide social
acceptability

simple inspection and
cheap maintenance
low procurement
and operating costs,
low fuel consumption
excellent design
and comfort for recreation
optimal load and
power parameters
efficient driving characteristics

high
convenience
perfect navigation
and communication
technology
high level of
mechanical safety

means of
transportation

low pollutant and
climate gas emissions

easy disposal,
totally recycling

Fig. 17.1 Expectations regarding properties of new load vehicles

17.1.1 Near Future Phases of Development

It is predicted that new technologies will make it possible to decrease the prices of
small cars to a reasonable level. Therefore cost-efficient and low performance
four-seat family cars will be increasingly used in both highly developed and
developing countries.
The trends indicate the largest growth rate to be in freight transportation in all
industrial sectors. The number of commercial vehicles is expected to increase by
about 55% in the next 20 years.

17.1.1.1 Combined Combustion System

Homogeneous and lean combustion is essential to further decreasing fuel con-
sumption. The aim is to lower pollutant emissions in the engine not in the exhaust
gas after treatment system because the use of an external system behind the engine
can considerably increase the fuel consumption.
Homogeneous burning aids both the spark and the self ignition engine in two
ways:

• In the spark ignition engine the burning process is similar to the advanced self
ignition engine which operates with lean and homogeneous fuel mixture in the
combustion chamber. This technique is called Controlled Auto Ignition (CAI); and
• In the self ignition engine the burning process is similar to the advanced spark
ignition engine which operates with high pressure fuel injection and high
exhaust gas recirculation rates. This technique is called Homogenously Charged
Compression Ignition (HCCI) [ 3 ].

With CAI and HCCI technology, particle emissions should be almost com-
pletely eliminated. The NO and NO 2 emissions can be decreased by up to 4% and
fuel consumption by up to 5% compared to a traditional self ignition engine which
uses a conventional high pressure injection. A disadvantage is the higher emission
rate of CO and HC at lower loads. Improvements can be attained by improving the