Technology
investment in the right type of renewable fuels, the transition to
renewables should be straightforward.
The next big step in increasing engine efficiency / lowering fuel
consumption is its combination with electromobility. The demand
on engines in the future will not be so varied as it is today. There is a
difference between how efficient an engine is at its ‘sweet spot’ and
how efficient across the entire real-world operating range. Partnering
engines with electric motors, as in parallel hybrids, allows the engine
to run at its most efficient level. Without doubt, electrification will
form part of the future combustion driveline solution.
Other technology can help lower fuel bills. Examples are stop/
start technology and 48V electric systems that power ancillaries
electrically, rather than mechanically. These may all have future uses
in heavy-duty applications, once their robustness is proven. But
another important source of greater efficiency is heat recovery. This
is not an easy task on heavy-duty engines since they run relatively
cold exhausts, but there is still hope to capture it and make it
commercially viable.
The diesel engine has a theoretical system efficiency of
between 55 and 60%. For reference, the best power stations
operate at 50–55% efficiency, and fuel cells are also around
50%+ efficient — so diesel engines can be incredibly
efficient. This, added to the fact that engines working with
electrification will often have a lower power demand, will
mean fuel use is set to decline in the future.
The diesel combustion engine remains a very cost-efficient
solution for creating mechanical energy. That said, legislation,
especially in Europe, is pushing towards electrification quite
strongly, and that may impact directly on the combustion
engine’s longevity. Our feeling is that its use will be
application-based, and that it will continue for a considerable
time in long-distance uses, such as ocean-going ships and
long-haul trucks. But even here, there will probably be a blend
of technologies in use.
The diesel engine — in a modified form — can be very clean and
efficient. It also plays well with electrification. As a manufacturer,
we need to find the best solution, based on the decisions that
society makes. Whatever they are, we need to be prepared. b
About the author
Dr Staffan Lundgren is a senior technology advisor for
Powertrain at the Volvo Group. Dr Lundgren is also a lead
strategist at the Volvo Group, specialising in evaluating new
technologies for the future of propulsion.