An industry-first technology developed in the UK could significantly cut nitrogen oxide emissions in diesel engines.
The Ammonia Creation and Conversion Technology (ACCT) created by academics from Loughborough University’s School of Mechanical, Electrical and Manufacturing Engineering is said to increase the capacity of existing on engine after treatment systems.
Nearly all new diesel vehicles are fitted with a Selective Catalytic Reduction (SCR) system to try and remove nitorgen oxide (NOx) emissions produced by combustion. This system uses so-called AdBlue to safely provide the ammonia required to reduce NOx into nitrogen and water.
According to the University, AdBlue only functions well at high exhaust temperatures, typically in excess of 250ºC, so the SCR does not necessarily operate at all engine conditions, for example, during short, stop-start commutes, particularly in urban areas or on construction sites. Furthermore, the use of AdBlue at these lower temperatures can result in severe exhaust blockages and subsequent engine damage.
ACCT is an AdBlue conversion technology that uses waste energy to modify AdBlue to work at these lower exhaust temperatures. By greatly extending the temperature range at which SCR systems can operate the new technology significantly enhances existing NOx reduction systems.
Loughborough’s Prof Graham Hargrave developed the technology with Research Associate Jonathan Wilson.
“We are all familiar with the ‘cold start’, where diesel vehicles spew out plumes of toxic emissions before their catalytic systems are up to temperature and able to work effectively,” said Prof Hargrave.
“Unfortunately with many vehicles doing short stop/start journeys, such as buses and construction vehicles, many engines never reach the optimal temperature required for the SCR systems to operate efficiently. The result is excessive NOx being released into the urban environment, especially in large cities.
“Our system enables the SCR systems to work at much lower temperatures – as low as 60ºC. This means that the NOx reduction system remains active through the whole real world driving cycle, leading to significant reductions in tailpipe emissions.”
Currently the Loughborough technology has been tailored for HGV’s, however the same system is said to be fully scalable for use in all diesel vehicles.
“No viable alternative to the diesel engine currently exists for the heavy duty market and is going to be in use for many more years,” said Wilson. “Systems are needed now that tackle NOx emissions, to help reduce the number of air pollution related deaths and enable vehicle manufactures to meet the ever reducing emissions targets set by the Government. ACCT is the answer.”
The Energy Technology Institute’s (ETI) Chief Technology Officer for Heavy Duty Vehicles, Chris Thorne said: “Based upon a brief review, the ACCT technology recently developed by Loughborough has the potential to viably produce gaseous ammonia at temperatures significantly below 190°C, thus enabling increased conversion efficiency and lower NOx emissions.
“It is likely that emissions legislation will become even tighter and vehicle manufacturers will need to develop technologies to address this, and it is our belief that the ACCT technology should be further developed as it could help address this challenge in the real world.”
In 2015 the Government estimated that exposure to NOx and particulate matter emissions from diesel engines lead to around 52,000 additional deaths in the UK. NOx emissions are also the primary cause of smog in major cities around the world and a growing public health concern.
This looks very exciting and much needed given the large number of short journey travel that occurs.
Wonder whether the quantity of coolant-water in diesel engines could be reduced to increase heat-up rates? My diesel takes about 5 miles to reach design oil temperature, while my wife’s petrol engine heats-up in less than one mile.
Very good observation, Jack. But a careful analysis needs to be made as coolant quantity is only one factor. I’ve seen that small (automobile) diesels still need robust block and head construction in order to support the large stresses that a diesel engine has to bear, compared to a petrol one. Therefore, thermal inertia is partly due to coolant, but robustness of the engine still results in a large mass to heat. Maybe additional features need to be considered, for example ceramics that could contain the heat inside the engine, rising efficiency, or a better coolant recirculation (Assisted by a pump during heating?) that eases the heating, shortening the time to proper temperature. My wife’s car heats up faster than mine. Her’s engine is 2.0L that has only 5 litres of coolant, and mine is a 2.4L that has 8.5 litres of coolant, her car is ready after 2 minutes, mine is still reaching operating temp after almost 4 minutes. And I have traced the difference to her car having numerous additional small hoses that redistribute coolant to the rear of the block and head, probably reducing the heat-up time (albeit reducing somewhat the reliability, as there are more hoses and connections to fail).
“emissions from diesel engines lead to around 52k additional deaths” :: exaggeration for effect evermore evident in Engineer’s un/ill-educated ecomentalised editorialism: viz maths.cam.ac.uk David Spiegelhalter feb17 WHO estimate 16k deaths from air pollution _ RCP state upto 40k _ Emissions are a quarter of 1970 levels _ uncertainties should be better reflected in the public debates.
Quite True Neale, here in Mexico City, the Phanatic and Eco-Idiot city major has manipulated numbers in order to support his personal campaign against the common car driver. His published numbers were on the order of 17k deaths “due to car produced pollution”, but a much more careful analysis by researchers at the National Autonomus University of Mexico (UNAM) explained that ozone effects could reduce the LIFE EXPECTANCY of UP-TO 17k people BY “several weeks”, and that is a completely different scenario! Now, ozone levels are nowadays at one tenth of what levels were several decades ago, but ecologists and tree-huggers believe measures should be harsher yet. Interestingly, two weeks ago Mexico City underwent severe traffic restrictions because of slightly exceeding the ozone limit at one or two of the many measuring stations. The curious thing is that ozone readings actually increased during the several days that the car traffic was reduced, which showed that the correlation is much more complex and that restrictions solved nothing.
Even one death per year due to car emissions is one too many. It could be anyone. I just hope that these technologies will be adopted by car manufacturers as soon as possible and at minimal or no additional cost to the consumer. Such systems must also be easy to maintain, and not having to rely on expensive garage bills to keep them going efficiently. I also like the idea of finding ways to entice engines to reach optimum temperature as quickly as possible in order to reduce higher emissions. Perhaps one way of doing this is to have a small heater, similar to a glow plug, at the bottom of the sump which is thermostatically controlled so that it goes on when the oil temperatures goes below a predetermined level. A bigger battery would be required to cater for this, but the benefits could be very interesting, since fuel consumption is also at its highest when the engine is warming up from cold. Keeping the engine oil always warm would be beneficial in reducing emissions and in reducing fuel consumption. Of course, the additional heater must automatically switch off, say 12 hours after switching off the engine, to prevent the battery from running completely flat.
Now there’s a a surprise: a consumer that wants something for nothing. If someone would be so kind as to arrange the manufacturer and developers to produce the technology for free?…then well done
Most Nordic vehicles already have built in sump heaters.
“emissions from diesel engines lead to around 52,000 additional deaths in the UK”
Goodness! So those people were killed by diesel emissions. Terrible! without that they would have lived forever.
Would it not be more reasonable to say that diesel emissions contributed to a shorter lifespan. Can we have a bit more reasoned reporting.
Well Kevin–that’s an interesting– novel one might say–approach to the problem of diesel emissions. So people dying from them doesn’t matter in the slightest, as they will die anyway? So we can assume that you would be happy dying young, from diesel fumes, knowing that death would come some time in the future anyway?? With opinions like that, possibly you wouldn’t be missed
I think that the real issue here is the statement of about 52000 additional deaths. This figure is potentially very misleading as it is derived from a correlation approach and has limited truth or accuracy. The estimate is the high value from the correlated data but does not say that these people would not have died otherwise that year. It is instructive to read the source material: you will have more doubts about these claims then I am sure.
Taking-up Neale Thomas’ theme about the fear campaign being launched regarding pollution: it is important to engineering that the correct information is passed and that is not these scare stories about thousands of “additional deaths”. The medical statistics that are used are far from rigorous and the presentation methods are vague: when they say additional deaths they mean earlier than would have otherwise occurred. It would be clearer if they expressed it in reduced life expectancy, but their attempts at that make the issue just as vague: they present life expectancy for people born this year as being reduced by a few weeks; knowing that there is no way that this can ever be subjected to testing. The use of thousands of “additional deaths” is both misleading and alarmist in the extreme.
We need good information about proven links to respiratory diseases, such as cross-country comparisons; but fear campaigns must be resisted as they lead to squandering resources.
Is it not a well known medical fact that poor air conditions are most harmful to the young with their developing lungs?. Is that not a good enough reason to promote the reduction instead of grumbling about the accuracy of some statistics on death rates attributed to NOx emissions.
Can I point you in the direction of Amminex who use metal hydride and water to produce Ammonia directly at low temperature. Thus facilitating low temperature operation of after treatment units.
http://www.amminex.com
Volvo has put block, sump heaters on their engines for many years. They have through their Volvo/Scania group had preheaters in the exhaust catalytic units to warm the units up quickly when the engine starts; they automatically turn off when the CAT reaches operating temp. Many cars in Scandinavia have this feature on both the Gas and Diesel exhausts.
So nothing is new from anyone, just needs to be fitted – the warmer everything is on an engine the better things are, and emissions can be reduced quickly. Why reinvent the wheel?
Technology already in the market. Seems to be a copy.
http://baumot.twintecbaumot.de/en/products/bnox-scr-system/
If the government legislate for reductions and cleaner air pollution, the manufacturers will meet the new requirements, ( by hook or by crook VW ) . It never happens, until manufacturers have to comply. Legislation forces manufacturers to change and include technology that they have already developed, but because of cost issues not implemented.
One thing that is being taken for granted and in reality is it not: The damn PCV or “Pressure Carter Ventilation” ( or any other name, for instance, VW call it “Crankase Ventilation”).
PCV consists of a vent where the blow-by gasses that get pass through the piston rings and go to the sump or “carter”, are piped back into the intake manifold and supposedly regulated by a kind of “valve”…
The bad thing is that oil vapors and small droplets get carried together and end up forming heavy deposits along the whole inlet tract, fouling the inlet manifold, the inlet ports and the inlet valves, as well as the inside of the combustion chamber, sparkplug and then the frontal part of the Catalytic Converter. An optimistic viewpoint is that by using that system, the engine will “burn” the oil vapors and therefore reduce emissions. Thas was quite true in the 70’s, when automobiles had large engines that emmited visible amounts of oil vapors at their “Road-Draft” tubes, that just get rid of fumes under the car. But the old (and still widely used) approach of piping the fumes back to the engine has been taken for granted as a “correct” solution. IT IS NOT. It reduces performance and causes several problems. The deposits coat the combustion chamber and promote preignition at large power demands under acceleration, they reduce the effectiveness of the cat converter and raise the NOx emissions considerably. Many afficionados to Turbo engines have noticed many years ago the oil quantity carried by the PCV system is not “negligible”, and that performance suffered greatly when the intercooler was covered inside with heavy oil residue from the damn PCV system, and devised a crude but effective way to reduce those deposits: a simple “Catch-Can”, that performed way more effectively at removing those residues than the factory designs, that use overly simple and ineffective “separators” improvised into the valve cover, the oil replenishment cap or so. But a well engineerd approach requires some form of cooling in order to condense the heavy oil vapors for the separator to be able to catch them as larger, liquid droplets; and a much better separator that uses centrifugal, mesh and proper flow design to effectively remove the oil droplets. Research by Afton Chemical (providers of additives for gasolines at the refinery level) has shown that latest engine designs opted for smaller gasoline engines supplemented by small turbochargers, in order to lower fuel consumption and emissions, BUT found that the small (microscopic) oil droplets from the piston rings and the PCV system actually favored preignition under part throttle conditions that generate medium Boost levels, so that the engine controls kept reducing spark advance and boost to preclude severe detonation, reducing performance and rising emissions. Thus, far from “reinventing the wheel”, some engine systems still NEED to be reevaluated. Few industries are as stubborn and change resisting as the automotive industry: once a way to do a thing gets established “as it is”, it takes a lot of effort and pressure to be reevaluated and fixed properly.
Car manufacturers have much to answer for. Don’t car manufacturers have a moral, ethical, social and legal responsibility to protect people from the harmful emissions that their car engines produce? How long will they continue to poison people with the emissions from their cars? When will they start to ALSO look at peoples health instead of concentrating mostly on the top line of sales and the bottom line of sometimes exaggerated profits? When will they start to also publish actual NOx emissions and real world fuel consumption of their cars, instead of fooling people with laboratory test results? Have we not been literally taken for a ride by at least some car manufacturers who have cheated on emission levels? Is it not true that some car manufacturers do even bother to include proper maintenance instructions regarding the DPF’s in the official manual of some of their diesel cars, leading to filters getting clogged unnecessarily, costing around £1000 to replace? Is this not a money spinner and totally unacceptable? Perhaps when a group of people who can medically prove that they have been negatively affected by car engine emissions, collectively sue car companies for health damages sustained, then car companies will be forced to clean up their act by cleaning up their car engines. That would be quite an interesting legal exercise and many lawyers would be rubbing their hands all the way to the bank at the expense of the car manufacturers. Perhaps the only other way as already suggested, is by introducing further and stringent legislation that will force car manufacturers into doing what is right. Is it not more than high time that car manufacturers do all they can to reduce engine emissions to near zero by utilising technologies have existed for decades, and implement new technologies such as that practically handed to them on a silver plate by the learned scientists at Loughborough University? And yes, should they not do this at minimal or no cost to the consumers, who by the way are the end users of their cars, and also the people in the street who are forced to consume the emissions given off by their cars?