Year in Review: Progress towards Decarbonizing Transport and Near-Zero Emissions

Abstract

<div class="section abstract"><div class="htmlview paragraph">As in the past several years, we provide here an overview of recent major regulatory and technological changes for reducing emissions from the transport and off-road sector. In the past, this review was focused mostly on improvement in engine efficiency and tailpipe emissions of criteria pollutants. However, starting last year [<span class="xref">1</span>] we have increased the scope to broadly address the increased focus on greenhouse gas emissions and the emergence of various non-conventional fuel pathways to achieve the various decarbonization goals.</div><div class="htmlview paragraph">There are two broad themes that are emerging, and which we describe here. Firstly, that we are approaching the implementation of the last of the major regulations on criteria pollutant emissions from cars and trucks, led by Europe, through Euro 7 standards and US, through multi-pollutant standards for light- and heavy-duty vehicles. While electric vehicles are getting much of the headlines, most vehicles sold in the last year still had an internal combustion engine. OEMs therefore must continue to improve upon traditional ICE technologies to meet these upcoming standards, while also investing in alternative powertrains such as hybrids, electrics, hydrogen-powered vehicles, and engines running on renewable fuels. This is reflected in the increasing diversity of topics published and discussed at conferences, which we try to cover. Which brings us to the second theme: several major studies conclude that given the uncertainties of cost, infrastructure readiness, consumer acceptance and decarbonization of upstream energy generation, it is prudent to pursue all these diverse technology pathways. A ban on the sale of new internal combustion engines is one tool, but a limited one given that majority of the emissions are associated with those of the cumulative fleet, which will take decades to turnover.</div><div class="htmlview paragraph">We describe the major regulatory developments along with the implications for technologies, both for light- and heavy-duty vehicles.</div></div>

Contribution of Road Transport to Pakistan’s Air Pollution in the Urban Environment

“…In addition to these exhaust emissions, non-exhaust emissions (as PM) are also produced by vehicles, most notably from brake, tyre, and road wear, and re-suspension of previously deposited roadside dust [42]. While in automotive markets with strong exhaust emissions regulations (e.g., the Euro 6d or Carb LEV III [43]), non-exhaust emissions are becoming the predominant source of PM emissions [1], in a market like Pakistan with weak emissions regulations (Euro 2), exhaust emissions are of greater concern. In fact, modern engines emit harmful exhaust pollutants in incredibly low amounts-so much so that it is starting to be claimed that "we have effectively solved the exhaust pollutant emission problem from internal combustion engine vehicles" [1].…”

“…Resultantly, PM emissions, which have traditionally been very low for petrol engines, have become notable. Modern emissions regulations like Euro 6 thus have strict PM (4.5 mg/km) and particle number (6 × 10 11 /km) limits [43].…”

Ammonia Emissions from Combustion in Gasoline Engines

“…In the recently announced Euro 7 regulations, based on a technology/fuel-agnostic approach, a 20 mg/km limit on NH3 emissions has been proposed for all light-duty vehicles [5]. For heavy-duty vehicles, which already had NH3 limits in the Euro 6 framework, allowable limits have been changed from 10 ppm to 65 mg/kWh.…”

Nozzle Design of Plug-and-Play Passive Pre-Chamber Ignition Systems for Natural Gas Engines

“…Driven by increasingly stringent fuel consumption and emission regulations [1], the powertrain industry has striven for innovation to meet the ambitious greenhouse gas and CO 2 reduction targets [2,3]. For long-haul transportation, heavy-duty engines are still expected to dominate the market in the foreseeable future.…”