As rules to boost fuel economy and lower carbon emissions in vehicles around the world continue to stiffen, acronyms like EREV, CNG, and MPGe are becoming more and more common. Ever wonder what they all mean? This glossary is your chance to enter a veritable Twilight Zone of terminology--and find out, say, whether a PZEV is related to a PHEV... Green Car Glossary: vehicles, emissions, fuels, electric cars, powertrains energy (updated)
As rules to boost fuel economy and lower carbon emissions in vehicles around the world continue to stiffen, acronyms like EREV, CNG, and MPGe are becoming more and more common. Ever wonder what they all mean? This glossary is your chance to enter a veritable Twilight Zone of terminology--and find out, say, whether a PZEV is related to a PHEV... 
As numerous political probes over the years have famously shown, once investigators dig into the circumstances around an alleged crime, anything can happen. The September 2015 announcement by the EPA that VW Group engineers had admitted to deliberate cheating on U.S. emission tests of the company's "clean diesel' engines may prove to be another... 
Almost one-third of the heavy trucks on U.S. roads now use the most stringent emission-control systems, which radically reduce their emissions of nitrogen oxides, soot, and other pollutants. Commercial trucks log much higher annual mileage than passenger cars, especially the semi tractors that haul long-distance freight across the country. That... 
The phrase "clean diesel" is largely associated with Volkswagen's diesel emission deceit, but the latest diesel technology can honestly be described with such a phrase. Semi trucks using the latest-generation clean diesel technology have reached a new milestone—they now make up 30 percent of the United States' fleet of trucks. The benefits... 
Drivers in the U.S. have longer commutes than those in Europe and Asia, on average. In the U.K., short commutes in vehicles with combustion engines—whether gasoline or diesel—pose particularly tough emission problems. That's because the exhaust aftertreatment systems have to warm up fully before they cut emissions to the levels... 
A global push to reduce vehicle emissions and create cleaner air for future generations has been underway for half a century now. However, while many governments around the world have introduced lower emission and higher fuel-efficiency standards for passenger cars, another large contributor to global emissions has mostly traveled under the radar... 
To most North Americans, the idea of banning all vehicles with internal-combustion engines seems unthinkable. Filling up with gasoline (or diesel) is as American as are dispersed low-density suburbs without mass transit, bike paths, or even sidewalks. Europeans, more of whom live in cities and most of whom have access to a more balanced set of... 
The Trump Administration has had a challenging start on numerous fronts, but its work to slash emission rules and eliminate regulations continues. The EPA administrator, climate-science denier Scott Pruitt, has said he isn't "currently" planning to target target California's ability to set its own emission rules. In March, the agency previously... 
Diesel-powered vehicles are facing a tough road ahead as more European cities move to ban older, dirtier, oil-burning cars. Diesel has long been the preferred fuel of European drivers thanks to its efficiency and lower carbon dioxide levels. However, mounting research has shown diesel-powered cars spew harmful toxins that may cause cancer and... 
Sometime between March 1 and 7, a specific page vanished from the website of the U.S. Environmental Protection Agency. Amidst coverage of the removal of the word "science" from the mission statement of the EPA's Science and Technology Office, it went largely unnoticed. First posted in December 2008, and modified several times over the next eight... ![Electric-car wells-to-wheels emission equivalencies in MPG, May 2017 [Union of Concerned Scientists]](http://images.hgmsites.net/tmb/electric-car-wells-to-wheels-emission-equivalencies-in-mpg-may-2017-union-of-concerned-scientists_100608699_t.gif)
Electric cars have no tailpipe emissions when running. But unless they're charged entirely on renewable energy—still statistically unlikely today—there are emissions associated with generating the electricity used to charge their batteries. For several years now, rigorous "wells-to-wheels" analyses of the carbon-dioxide emissions... ![Electric cars dominate U.S. climate-friendly vehicles [data: U.S. EIA; map: Climate Central]](http://images.hgmsites.net/tmb/electric-cars-dominate-u-s-climate-friendly-vehicles-data-u-s-eia-map-climate-central_100608171_t.gif)
The question is a reasonable one: electric cars may be zero-emission, but what about the electricity to recharge them? While renewable energy is growing globally, burning fossil fuels is still the source of most electric power today. The good news is that in most areas of the U.S., the "wells to wheels" carbon-dioxide emissions associated with... 
The Volkswagen diesel scandal left lasting imprints on the entire automotive industry, and may have changed the way regulators look at vehicles using the fuel forever. That's true not just in the United States, but elsewhere as well. The European Union is now increasing its efforts to make sure a scandal like Volkswagen's can never happen again... 
During President Donald J. Trump's half-hour meeting with Pope Francis at the Vatican yesterday, the pope gave the president a copy of his 2015 encyclical calling for urgent, drastic cuts in fossil-fuel emissions. It is unclear whether the U.S. president will peruse the document. Back at home, however, his administration is continuing unabated in... 
Carlos Ghosn, the man behind the Nissan Leaf electric car and now the chairman of the Renault Nissan Alliance, isn't the first to say it. But his recent comment that cities are driving the push for electric cars is an important one, because it indicates a prime market for their advantages. The result is that city governments all over the world are... 
The U.S. Justice Department may be planning to file a lawsuit against Fiat Chrysler over allegations that the engines in its light-duty diesel trucks included equipment to defeat Environmental Protection Agency emissions tests. A report from Bloomberg last week cites unnamed sources who were briefed on the forthcoming suit. The equipment in... ![Smog obscures George Washington Bridge, 1973 [From EPA Documerica series]](http://images.hgmsites.net/tmb/smog-obscures-george-washington-bridge-1973-from-epa-documerica-series_100594067_t.gif)
Much of the news out of Washington, D.C., these days has to do with the possibility of political scandal. But the wheels of government keep turning, and significant changes are happening at numerous agencies charged with missions as diverse as collecting intelligence, supporting education, and protecting the environment. Few groups are seeing... 
When a major lobbying group issues a statement replying to an academic study before that study even hits the media, you know it's major. On Monday, the Diesel Technology Forum responded to an article in Nature with a statement that supported "improved real-world testing" of diesel emissions. Those more stringent tests, the group's executive... 
Today's political climate has made for fluid motion in regulations, and corporate average fuel economy targets haven't been left out. Suppliers and automakers have already begun investing heavily into vehicles to be sold in 2022 through 2025, which will include various fuel-saving and emission-reducing technologies. However, that unsettled...