The EPA should
reconsider the current strict mandate on Diesel road-legal
emissions,regarding their particular operation in a counterpoint to a
regular spark-ignited engine. Some devices such as the EGR and SCR
actually just transfer the pollution from the truck's tailpipe to an
industrial chimney.
The EGR (Exhaust Gas
Recirculation) leads to an increasement in the Diesel fuel
consumption, which can be easily diagnosed from the enhanced
particulate matter emissions, altough the Diesel Particulate Filter
(DPF) hides this problem. Due to its prejudicial interference in the
combustion process, the EGR is not compatible with a more accurate
tuning for fuel-savings, which could lead to imrpovements not just
environmentally-wise but also regarding national security due to the
lesser dependence on foreign oil from politically-unstable lands.
The DPF getting more
demanded also leads to an increasement on the regeneration cycles
required to keep its operational conditions, also enhancing the
Diesel fuel consumption. We all know the oil drilling, refining and
logistics involved in the final destination of its derived products
(gasoline, Diesel fuel, kerosene, among others) have its own
environmental impact and a high energy expense, enhanced due to the
misguided EPA standards which are actually not so effective
concerning to environment protection.
Another
currently-mandatory device, the SCR (Selective Catalyst Reduction) is
also not so “clean”, since it increases the logistics complexity
involved in Diesel vehicles' operation and leads to a high
consumption of purified water, and also in case of an accident with
leakage from the on-board urea tank it can easily contaminate water
courses nearby, including underground waters.
Winter time is also
critical for Diesel operators, since EGR-equipped vehicles have
harsher start-ups and take a longer time to get a stable idling
speed, which increases the particulate matter emissions due to the
longer cold-phase after the start-up. The SCR is also a source of
problems, since the urea-based fluid is easily prone to freezing due
to the 67,5% water content.