If you have not heard of the term “Environmental Justice” or “EJ” as it is abbreviated, then it’s time to read up. Policy makers have to pay close attention to this topic in the quest for a rapid transition to greener energy and mobility.
If you have not heard of the term “Environmental Justice” or “EJ” as it is abbreviated, then it’s time to read up. Policy makers have to pay close attention to this topic in the quest for a rapid transition to greener energy and mobility.
Daimler Truck has improved it’s 15L engine for Class 8 long-haul trucks in North America. This article covers a few of the discussed improvements.
Achieving 90% reduction in NOx emissions from heavy-duty vehicles California’s Low NOx Omnibus will be phased in through model years 2024 – 2031 and will require >90% reductions in tailpipe NOx emissions from heavy-duty trucks. This is a high-level summary of a multi-year program led by Southwest Research Institute to demonstrate the feasibility of achieving these targets. Background Starting back in 2014, California’s Air Resources Board (CARB) initiated a program to evaluate the feasibility of reducing tailpipe NOx emissions from heavy-duty vehicles by 90%. Southwest Research Institute (SWRI) has led this comprehensive study in three stages, through implementation of advanced engine and after-treatment solutions. A key objective of the study was to demonstrate meeting the upcoming NOx standards without incurring a significant fuel or CO2 penalty. For a quick overview of California’s low NOx Omnibus rule starting 2024, the reader is referred to this link. Summary A combination of modified engine calibration, implementation of new hardware and an advanced after-treatment system with close-coupled catalyst was implemented. After accelerated aging representative of 435,000 miles, the final tailpipe levels were at 0.02 g/bhp-h on the FTP cycle, right at the Low NOx Omnibus target. Even on the challenging low load cycle, NOx
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 Clean Cars 2.0 : Emission standards beyond 2025 Based on workshops held by California’s Air Resource Board (CARB) Background California has the world’s toughest gas emissions standards for light-duty vehicles. The standards phase-in to 30 mg/mi of combined non-methane organic gases (NMOG) and nitrogen oxides (NOx) by 2025. CARB is now considering tightening these and other standards even more beyond 2025, while also promoting reduced fuel consumption and electrification of the fleet. A few key takeaways follow. Non-ZEV SULEV 30 fleet and pathway to 100% EV sales by 2035 California’s Air Resource Board (CARB) is aiming for further NOx and particulate reductions from the light-duty fleet. Here’s a summary of the proposed approach, based on a workshop held on May 6th, 2021. Fleet Electrification CARB Electric Vehicle Sales Targets Goal is to achieve 100% plug-in electric sales by 2035. Move from credit driven to sales driven approach: one ZEV credit per ZEV, with 5-year credit life. PHEVs must have > 50mi all-electric range, must be able to complete US06 on all electric mode, and meet SULEV30 & zero evaporative emission standards. 20% cap on PHEVs allowed to fulfill OEM obligation to ZEV requirements. As input to cost modeling, it
GPFs work well under wide operating conditions. But, very higher filtration will be needed for Euro 7. Journal Paper Review : Particle Number Emissions of a Euro 6d-Temp Gasoline Vehicle under Extreme Temperatures and Driving Conditions https://www.mdpi.com/2073-4344/11/5/607 Background Tailpipe particle number (PN) measurements were done on a Euro 6d-temp vehicle with a close-coupled TWC and uncoated GPF in the underfloor position. Ambient temperature and driving conditions were varied. Key Takeaway (1) The tailpipe PN emissions were well below the Euro 6d limit over a wide range of ambient temperatures (-30 to + 50 C), when driving aggressively (dynamic RDE) and under stop & go conditions (“Transport for London, TfL” test), and even when including particles down to 10 nm. Key Takeaway (2) Tailpipe PN emissions were low even at very low ambient temperatures. Surprisingly the emissions peaked at 5 deg C and not at the lowest temperature (PN is expected to increase with low ambient temp. due to fuel impingement on colder surfaces and incomplete combustion). However, the authors point out that a dynamic RDE test was done before the testing at 5 C, so that the filter was most likely passively regenerated and was in a “clean” state (i.e. without
