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All quiet on the engine front

Posted: February 23, 2015 by Rolf Lockwood

TORONTO – After well over a decade of endless wrangling over emission-control technologies and non-stop complaints on the user side about cost and reliability issues, things had gone quiet on the engine front. It hasn’t been this way since the U.S. Environmental Protection Agency (EPA) started tinkering with things back in the 1990s.

In fact, the EPA was at it as early as 1974, though the broad and heavy crunch came later. It really began in 1997 when the EPA set the standard for model years 2004-06.

But after all the trouble and woe brought on then and later with the 2007 emissions regime, which linger on for many of you, the 2010-spec heavy-duty diesel has proved to be a huge improvement in terms of both reliability and fuel economy.

Are we back to where we were a dozen-plus years ago? No, and there are still challenges in some quarters, but compared to EPA ’07 we’re way ahead. And a lot of folks probably haven’t even noticed that we’re already well into the next EPA era. Things changed with the 2014 model year, though the shift was a relatively small one in practical terms. It won’t stay that way for long, as the focus is now on fuel economy and greenhouse gas emissions (GHGs). More on this later.

So how did we get here?

The Nightmare Begins

Remember the ‘consent decrees’ of 1998? Agreements between the EPA, the California Air Resources Board (CARB), and most engine manufacturers, they were the end result of a battle in which the authorities claimed that NOx emissions had been misrepresented for several years. The EPA claimed that Caterpillar, Cummins, Detroit Diesel, Volvo, Mack, and Navistar used engine control software that created a more fuel-efficient steady-state highway cruising mode – but one that allowed higher NOx emissions. In the EPA’s eyes, this was an illegal “emission defeat device.”

The engine manufacturers reluctantly capitulated, and one of the results was that most of them had to comply with the already-established 2004 emission standards early, as of October 2002. There were also fines and requirements to allocate funds for pollution research. Of course they also had to switch their engine control strategies.

For model years 2004 through 2006, the EPA’s new emission standards aimed primarily to reduce NOx emissions from highway engines to levels of approximately 2.0 g/bhphr. So most manufacturers introduced what we’ve come to know and love as exhaust gas recirculation (EGR). The fun had begun.

Changes in 2007

Move on to model year 2007 and later, with the focus now on both emissions and diesel fuel itself.

That’s when we got low-sulfur diesel fuel, with the sulfur content in on-highway diesel fuel chopped to 15 ppm from the previous 500 ppm. The reason was that sulfur plays havoc with the catalytic diesel particulate filters and NOx catalysts that engine makers had to use for 2007-10 emission requirements.

We got new and stringent limits for particulate matter (PM), down from 0.10 to a tiny 0.01 g/bhp-hr, effective on Jan. 1, 2007. And NOx had to be cut back further, down to 0.20 g/bhp-hr, but manufacturers could phase that in between 2007 and 2010 on a percent-of-sales basis: 50 percent in 2007 through 2009 and 100 percent by 2010. Hardly any engine sold through the end of 2009 met the ultimate NOx standard, and it seems most engine makers certified their engines to a NOx value of about 1.2 g/bhp-hr on average.

And then came 2010, by which time NOx had to be down to that difficult 0.20 g/bhp-hr, which necessitated some big engine changes. There wasn’t actually a new regulatory demand because the NOx requirement had been established as part of the 2007 regime. In theory, had the technology been available, engine makers could have dealt with the 0.20 NOx requirement back in 2007.

That brought us selective catalytic reduction (SCR) and diesel exhaust fluid (DEF) and that’s where most folks are now, with significant fuel economy improvements compared to 2007. And after more than a decade of work refining things like sensor technology, strides have been made on the reliability front.

There was also a small but significant change in 2013 with the requirement for on-board diagnostics (OBD) for all on-highway diesel engines. It monitors the truck’s emission system to detect issues and recognize faults. When things go awry, the driver will know by way of a dash lamp known as the Malfunction Indicator Lamp (MIL). If it lights up the red ‘Stop Engine’ lamp, it means what it says. These diagnostics cover the engine at large too, meaning potentially expensive problems can be seen and dealt with early, before they absorb large amounts of cash in repairs or low fuel economy.

So What’s Next?

Well, now things get interesting in altogether new ways, thanks to a 2010 decree by U.S. President Barrack Obama that the EPA, working with the National Highway Traffic Administration (NHTSA), should attack things in a new way.

The 2014 fuel economy and greenhouse gas regulations, finalized in August 2011, are known as Phase 1 of a longer-term GHG plan. Given the breadth of applications in the truck world, they’re complex and at first blush seem arbitrary. The GHG targets are mainly carbon dioxide (CO2) but also methane and nitrous oxide.

Official projections tell us that this effort will save 530 million barrels of oil, 270 million metric tons of GHGs, and US$50 billion in fuel costs.

The rules divide trucks into three groups, starting at 8,500 lb GVW, thus including medium- and heavy-duty pick-ups and vans, trailer-pulling tractors, and vocational vehicles. Note that whole tractor-trailers are not targeted.

Starting with 2014, tractors must achieve as much as a 20-percent reduction in CO2 emissions and fuel consumption by 2017. There are separate engine standards; heavy-duty engines had to have a three-percent improvement last year rising to six-percent by 2017.

For heavy-duty pickup trucks and vans, the standard demands a phased-in improvement reaching 15 percent by the 2018 model year.

Mixers, refuse haulers, and other vocational machines have to get to a 10-percent reduction in fuel consumption by 2017. Again, separate engine standards apply, which called for a five-percent improvement last year, rising to nine percent by 2017.

In practice, none of this caused a stir last year, and by all accounts targets were met with ordinary improvements of existing hardware and software. Obviously, things will get tougher as 2017 approaches but it’s unlikely that radically new hardware — like waste-heat recovery – will be required.

And Phase 2?

A great deal of controversy already surrounds this next phase of the fuel-economy and GHG-reduction effort, as President Obama demanded in February of last year. Nothing is yet clear.

We do know that the second phase will demand even tougher carbon-dioxide and fuel-consumption reductions in heavy- and medium-duty trucks. And we know that we’ll see the first draft of a rule next month followed by a final regulation some time in 2016. Our firm knowledge stops there.

It’s likely that testing procedures will change. Phase 1 is being dealt with entirely by computer modelling, and while that general approach is likely to continue, things seem bound to get more rigorous.

Among the key issues is whether trailers should be added to the mix. It’s likely, and it’s equally likely that certain aerodynamic devices will be required.

The biggest single issue may be the way engines are dealt with. There are two camps, one saying they should continue to be tested separately, the other – not surprisingly led by the truck makers with their own diesels – urging that the whole truck should be tested.

We’ll have a closer look at this and other Phase 2 issues next.



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