Diesel ICE’s Vital Role in Combating Climate Change

Diesel powered internal combustion engines must play a vital role in reducing climate change and meet Paris Agreement emissions targets.

That’s the conclusion of a study highlighting the technology’s advantages in reducing CO2 being emitted from transportation tailpipes. In fact, coupled with renewable fuels such as hydrogenated vegetable oil (HVO) fuels, diesel engines can reduce a vehicle’s CO2 emissions by up to 66 % on a well-to-wheel basis. Scientists have known for years that diesel fueled engines emit considerably less green houses gases than gasoline engines yet the technology has again recently come under fire by clean air campaigners who point the carbon particulate and NOx emissions that have been blamed on many deaths annually of residents in traffic congested cities.

Yet now, a white paper put together by the Association for Emissions Control by Catalyst (AECC), Robert Bosch, Vitesco Technologies, IAV and FEV working intensively on the future of diesel vehicles suggests diesel technologies latest breakthroughs can combine its good climate credentials with a clean air potential even greater than gasoline. The paper, Improving Air Quality and Climate Through Modern Diesel Vehicles, concludes diesel vehicles are part of the future mobility because they are a medium-term solution to meet CO2 reduction targets, while having low pollutant emissions on the road, even under urban driving conditions.

The paper is authored by line-up of industry heavyweight including Joachim Demuynck (AECC), Andreas Kufferath (Robert Bosch), Oliver Kastner (Vitesco Technologies), Maximilian Brauer (IAV GmbH) and Michael Fiebig (FEV Europe GmbH). They analyzed the results of recent developments on demonstrator vehicles to show that a combined reduction in pollutant and CO2 emissions is possible with the latest diesel technology through an integrated system approach of engine, hybrid and emission control technologies.

The study goes into some depth about the measurements of tailpipe emissions including the effects of cold starting, catalytic converter heating and also the vehicle’s size affect on its emission rating. However, it points out: “Nevertheless, low emission results are still possible for all diesel passenger cars with state-of-the-art calibration or hardware measures.”

It adds that the advantage of diesel when used in clean air urban environments includes: “When continuously driving with a warm exhaust system at low average vehicle speeds, NOx conversion rates of up to 99 % and thus near-zero tailpipe NOx emission levels can be achieved. This condition can also be kept if the vehicle is restarted after a short stopping phase of a couple of minutes, as the exhaust systems are designed to retain the heat for as long as possible.”

Advances in particulate filters for diesel engines have also had a marked improvement of the tailpipe emissions. The study claims: “The introduction of the wall-flow particulate filter for diesel passenger cars and commercial vehicles allowed tailpipe particulate emissions to be reduced to a level that is no longer considered a relevant contributor to direct particulate pollution. Local authorities banning diesel vehicles without a particulate filter observed the success of this measure; Stuttgart for example no longer has a particulate matter alarm as of this year for the well-known hotspot “Am Neckartor”.”

It adds that the extra efficiencies enjoyed by a diesel engine over that of the gasoline will see an average like-for-like fuel saving of 20%, further reducing emissions for the mileage covered. Finally, it concludes: “Diesel vehicles… are a medium-term solution to meet CO2 reduction targets, while having low pollutant emissions on the road, even under urban driving conditions. The vision of a diesel powertrain with negligible impact on air quality is becoming a reality. In the long term, technologies are compatible with renewable fuels to maintain the low pollutant emissions while further reducing the carbon footprint on a well-to-wheel or lifecycle basis.

You can see the full finding at https://www.aecc.eu/wp-content/uploads/2020/09/200901-modern-diesel-MTZ.pdf

— Paul Myles is a seasoned automotive journalist based in London. Follow him on Twitter @Paulmyles_