California and Truck & Engine Manufacturers have reached a deal on low NOx and electrification targets in the state. This paves the way for more regulatory certainty but the challenges ahead are not diminished.
Opposed piston engines are being developed as a tool to reduce CO2 and NOx emissions from heavy-duty trucks. Here’s a deeper look into this technology and recent test results.
Heavy-duty vehicles cover a very wide range of applications and typical driving profiles. A one-size-fits-all approach is unlikely to work for reaching zero tailpipe emissions from this sector. Here’s a summary of the application diversity from a US viewpoint.
Here’s a summary of California’s latest thinking on “Tier 5” tailpipe NOx emission standards for off-road construction and farming equipment.
This is part 1 of 2 technology updates on pathways to meet the low NOx standards for heavy-duty vehicles set by California and being considered by the EPA for nationwide implementation starting model year 2027.
Here’s a summary of EPA’s proposed changes to tailpipe NOx and CO2 emission standards for HD trucks in the US beyond 2027.
Here’s a summary of possible changes to emission standards for passenger cars being considered as part of Euro 7.
SuperTurbo with Turbine Bypass for Cold Start Aftertreatment Heating Upcoming regulations such as California’s Low NOx Omnibus and Euro VII will require >90% reductions in tailpipe NOx emissions from heavy-duty trucks. This is a series providing a summary of various technologies which can help meet these challenging regulations. What is a SuperTurbo? SuperTurbo is a driven turbocharger that has the capability of mechanically transferring power to and from the turbo shaft, enabling both compounding of excess turbine energy, as well as supercharging capability for improved transient response and greater control over charge flow. This supercharging capability also allows for a complete turbine bypass to be used during engine cold start, while still providing boosted airflow to the engine. For heavy duty diesel engines, this ability to supercharge during times of zero flow to the turbine is important to retain drivability and functionality of the engine. The turbine bypass directs the hot exhaust gasses directly to the aftertreatment, resulting in rapid heating of the aftertreatment during a cold start. See the end of this article for a short video which explains the bypass operation. Benefits for lower NOx emissions SCR inlet temperatures over cold WHTC cycle Preliminary testing of the SuperTurbo
In-use NOx emissions from heavy-duty trucks and buses Journal Paper Review : Real-world NOx emissions from heavy-duty diesel, natural gas, and diesel hybrid electric vehicles of different vocations on California roadways Science of the Total Environment 784 (2021) 147224 Background This is one of the largest studies in California on measurement of in-use NOx emissions from 50 heavy-duty trucks and buses for various vocations. The fleet included 2 diesel vehicles without SCR (selective catalytic reduction of NOx), 14 diesels with SCR, 2 diesel hybrids, 29 compressed natural gas (CNG) and 3 liquified petroleum gas (LPG) vehicles. Emissions were measured using portable emissions measurement systems (PEMS) and on actual driving routes and applications (e.g. transit buses making stops and refuse trucks making the rounds collecting garbage and delivering to landfills). All vehicles had less than 435,000 miles of prior driving, so that these were within the useful life requirements. This is a good database to identify future potential of advanced powertrain & after-treatment technologies as we move towards the Low NOx regulations starting 2024 – 2027. Key Takeaway (1) Compared to diesel vehicles with SCR technology, CNG vehicles certified to 0.02 g/bhp-h standard emitted 94% lower NOx. LPG vehicles
California’s Air Resource Board (CARB) has passed what could be perhaps it’s last major regulation for reducing NOx and particulates from heavy-duty trucks and buses. The HD Low NOx “Omnibus” regulation practically touches upon every aspect of in-use emission reduction. Highlights summarized here.
