The resulting chemical reaction converts the nasty NOx fumes into nonpolluting nitrogen, water and carbon dioxide.
The problem is that both NOx and diesel fuel are hard to break down.
Diesel engine makers have been trying to block NOx where it originates, in the engine cylinders.
By the time a car achieves Euro V standards, emissions of NOx and particulate matter are negligible.
These gases are then used to clean up smog-producing nitrogen oxides, or NOx.
These include the exhaust gases such as nitrogen oxides (NOx), non-methane volatile organic compounds (NMVOCs), and carbon monoxide (CO).
Injected into the exhaust stream, the solution's ammonia reacts in the de-NOx catalyzer to form nitrogen and water vapor.
WSJ: 2013 Porsche Cayenne Diesel Review: Only Geeks Need Apply | Rumble Seat by Dan Neil
This interacts with the NOX and SOX to produce the dangerously small particulate pollution that leads to premature deaths.
To make adsorption more feasible, ArvinMeritor engineers went looking for a substance other than diesel fuel to attack the NOx.
Or nitrogen emissions (more exactly, NOx) from the use of artificial fertilisers contribute to climate change which will reduce crop yields.
FORBES: The Climate Vulnerable Forum Report: Really Not Very Good At All
Between 2007 and 2010 the agency also mandates a phased 92% reduction in the amount of NOx emitted from a truck's tailpipe.
One is exhaust gas recirculation, which pumps cooled exhaust back into the engine air intake, lowering the combustion temperature and reducing NOx formation.
In most systems that's done when a bit of diesel fuel is injected into the exhaust system, where it mixes with the stored NOx.
Instead the EPA is pushing the use of NOx "adsorption" systems, which act like giant sponges, essentially trapping the NOx chemically in the exhaust system.
That hydrogen and carbon monoxide mixture is then pumped into one of two NOx traps, where it strips the oxygen from the NOx, forming nitrogen, carbon dioxide and water.
The economic value of the health impacts was based on premature mortality, workdays lost, and other direct costs to the healthcare system resulting from emissions of PM2.5, NOx, and SO2.
FORBES: How Much Do Health Impacts From Fossil Fuel Electricity Cost The U.S. Economy?
Also, to comply with prevailing U.S. emissions standards on nitrogen oxides, or NOx, these big diesels require fairly complicated systems of postcombustion treatment with a water-based urea solution, called AdBlue.
WSJ: 2013 Porsche Cayenne Diesel Review: Only Geeks Need Apply | Rumble Seat by Dan Neil
By optimizing the split-cycle concept, the Scuderi engine is expected to reduce NOx emissions up to 80 percent and improve fuel efficiency by 50 percent, compared to a conventional gasoline engine.
They have shown that emissions of nitrous oxides (NOX) and sulphur oxides (SOX) combine with gases already in the atmosphere to create very fine particles that are especially dangerous to human health.
The findings suggested that the plants' NOx emissions could result in a 35% increase in the number of days when ozone levels exceeded the upper threshold set by the US Environment Protection Agency.
Scuderi says its split-cycle engine increases overall efficiency by up to 50 percent and cuts down on NOx gases at the same time by changing the way air gets channeled through an engine.
"It's the NOx where they're really struggling, "says Taylor.
That is, what do we get from a doubling of atmospheric CO2 (or more accurately, CO2-e, the effects of methane, NOX and so on converted to a common as if they were CO2 number).
In Europe the trucking industry has settled on a technology called selective catalytic reduction, in which urea is periodically injected into the exhaust system to break down the NOx, converting nitrogen oxides into (somewhat) harmless ammonia.
Because hydrogen can clean the exhaust right from a cold engine start, the plasma reformer method is 20% to 50% more efficient at reducing NOx than other clean-diesel technologies, allowing less unburned fuel to pass through in the process.
应用推荐