Mazda gives spark to gasoline engine: New tech improves gasoline engine efficiency by 30%
With new technology, Mazda gives spark to gasoline engine
New tech improves gasoline engine efficiency by 30 pct -
Mazda
Small Japanese producer has concentrated on fuel-sipping
engines
Mazda's SPCCI engines could be used in more efficient
hybrids
Published 3:10 AM ET Wed, 25 Oct 2017 Updated 8:47 AM ET Wed, 25 Oct 2017
In the high-stakes, high-cost battle among global
automakers to develop ever more efficient vehicles, one of the biggest
breakthroughs in internal combustion engine technology in years looks to be
coming from one of the industry's smaller players.
Japan's Mazda Motor Corp has zoomed past its larger
global rivals to develop an engine which ignites gasoline using combustion
ignition technology, a fuel-saving process considered something of a holy grail
of efficient gasoline engines.
As global emissions regulations get tougher, not only
could Mazda's technology prolong the life of internal combustion engines, it
could also improve "greener" engines as they can be used to produce
more efficient gasoline hybrid and plug-in hybrid vehicles.
Mazda will showcase the Skyactiv-X technology at the
Tokyo Motor Show this week. When it launches the engine in 2019, the automaker
says it will deliver as much as 30 percent fuel efficiency over its Skyactiv-G
engine, already one of the most fuel efficient gasoline engines on the market.
"Our resources are limited, so unlike bigger
automakers, we don't have the array of options in which to invest our R&D
funds," said Mitsuo Hitomi, managing executive officer at Mazda who
oversees engine development. "That's why we're betting on this technology
... We were determined that no matter what, we would develop this engine,"
Hitomi told Reuters in an interview at the company's headquarters in Hiroshima.
Churning out around 1.6 million in annual vehicle sales,
Mazda accounts for only a sliver of global car sales, and its R&D budget is
roughly a tenth that of automaking giant Toyota Motor Corp.
Many automakers with big spending budgets have invested
heavily in developing a host of new powertrain technologies, including gasoline
hybrids, battery electric cars and fuel cell vehicles, as fuel efficient
alternatives to gasoline and diesel vehicles.
But Mazda believes fuel-sipping engines are a better way
to reduce carbon emissions than cars powered by fossil fuel-generated
electricity, focusing on the Skyactiv-G high-compression gasoline engine, and
its diesel cousin, the Skyactiv-D.
Its latest technology is a variant of homogeneous charge
combustion ignition (HCCI) technology, which marries the clean-burning
qualities of gasoline engines and the fuel economy and grunt of diesel engines
to produce an efficient, powerful engine.
Precise timing required
Mazda's engineering team began developing the engine
around the time it completed developing its Skyactiv-G engine, which came out
in 2011.
From the start, solving the multiple variables required
to balance performance with successful compression ignition was a challenge so
complex and frustrating that there were "countless times" the team
wanted to throw in the towel, Hitomi said.
Engineers at General Motors, Honda Motor Co and other
automakers have also pondered how to develop a cost-effective way to control
the HCCI process, which requires precise timing inside the engine chamber to
achieve efficient ignition.
Hitomi and his team came up with a relatively simple
solution - to facilitate sparkless ignition, use a spark plug to light a
high-pressure "fireball" inside the chamber to compress the
super-lean mix of fuel and air.
The process is controlled by precisely monitoring each movement
in the combustion chamber, enabling visibility of when the intake valve allows
air to be drawn into the chamber to when the fireball is ignited.
"Kudos to them for taking the next step," said
Paul Najt, Group Manager of Research & Development at GM, which began
showing an early HCCI prototype around 2007.
GM has since applied HCCI technologies to develop
smaller, turbocharged engines, but Najt said the automaker was not developing a
full system at the moment due to cost concerns. In the meantime, it has
released gasoline hybrid and other electric models.
'A monster of an engine'
Hitomi said Mazda's spark plug breakthrough came during a
crisis point around two years ago, when the development team showed him an
early rendition of the engine.
"It had so many parts to it, like separate controls
for variable valve timing and intake and exhaust levels, that it had become a
monster of an engine," too costly to produce, he said.
The team then "performed massive surgery" to
simplify the engine, using a spark plug to achieve an even compression ignition
process and stripping unnecessary functions.
Now the Skyactiv-X engine consists of just three
additional key components compared with the Skyactiv-G: in-cylinder sensors to
monitor the combustion process, a high pressure fuel system to create the
optimal fuel mix and a supercharger.
The cost of the new engine "falls somewhere between
a gasoline and diesel engine", Hitomi says.
Massachusetts Institute of Technology Prof. William
Green, who has worked with HCCI development teams at U.S. automakers, said
Skyactiv-X's efficiency gains may be limited compared with hybrids and the even
larger longer-term potential benefits of EVs.
But the automaker could win over customers looking for an
inexpensive, fuel-saving option which does not require battery recharging time
or infrastructure, he added.
"It has the advantage of being simple and straight
forward, not expensive, and practical. Those are a lot of advantages."
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