4. Review of experimental investigations
A large number of experimental studies have been carried
out on diesel engines fuelled with biodiesel. In many, but not
all, cases the operational constraints i.e. air-fuel ratio and peak
conditions are maintained constant in both the biodiesel-fuelled
engine and conventional fuelled diesel engine. Investigations
that have been carried out at same operating conditions indicate
acceptable performance characteristics such as fuel consumption,
thermal efficiency, and overall reduction in emissions in biodiesel
engines. However contrary to the above, some experimental
investigations have indicated almost no improvement in thermal
efficiency and claim that exhaust emissions deteriorated as
compared to those of the conventional diesel engine. An attempt
will be made here to review the previous experimental
investigations on biodiesel fed engines.