Friday 29 August 2014

Opposed-piston engines set to bow?

Opposed-piston engines could be about to make a comeback as three US suppliers argue that their designs can give significantly improved fuel efficiency.

Two-stroke opposed-piston engines first developed in the 1930s have failed to catch on. However, with the opportunities afforded by modern technology, including new materials, powertrain developers claim they have updating previous designs to the point they can compete with more conventional internal combustion engine (ICE) architectures to which OEMs are accustomed today.

Both gasoline and diesel engines are being developed, one has been tested by the notable FEV GmbH which develops and tests engines and transmissions.

Opposed-piston engines were developed in the 1930s in Europe, primarily by Junkers in Germany before WW2, and subsequently by Napier (the Deltic) and Rootes Group in the UK. All were two-stroke diesel engines, the Deltic being the most complex engine ever built! The TS3 on the other hand was Rootes Group’s first diesel engine and appeared in Commer commercial vehicles. Rootes group formed part of Tilling-Stevens.

Monty Cleeves, founder, president and chief technical officer at Pinnacle Engines Inc. of San Carlos, California, whose opposed piston design the company claims can provide 30-50 per cent improvements in fuel economy without the typical cost penalty, believes that by focusing on developing automotive markets, his engines could reach the automotive market by 2018.

The company, based in Silicon Valley, has noted on its website that it is “launching its first product in 2014 in partnership with a major Asian vehicle OEM”.

And it claims that it has completed 500 hours of testing at FEV.

Meanwhile, EcoMotors Inc. of Allen Park, Michigan, is another opposed piston engine supplier targeting developing economies. It has also developed an electrically controlled turbocharger, and believes its opposed-piston diesel engines could be on the market even sooner than 2018.

Amit Soman, the company’s president and chief operating officer, has revealed that the company’s OPOC (opposed-piston opposed-cylinder) engine might be used by OEMs in Asia as soon as 2017.

“If you look at the off-highway market in Asia, it’s still not emissionised,” Soman is reported as saying. “It’s still where fewer performance characteristics are dominant, and that’s what our engine brings. It’s smaller, lighter and has good torque and power compared to other engines of its weight.”

He added: “Because of these characteristics, and because we don’t have to meet the challenge of emissions in the short term, we will focus on off-highway in emerging markets first. This gives us a foothold, allowing us to get the first half million engines on the market before we start focusing on the western, more ‘emissionised’ segments. Our first two manufacturing facilities are under construction in China, which will remain as our location of focus for a while.”

In March of this year. EcoMotors announced that in association with a subsidiary of First Auto Works it had formed a joint venture to develop, manufacture, sell and service advanced engines in China based on Opoc designs. These are two-stroke diesel engines and contain 50 per cent fewer parts than a conventional reciprocating internal combustion engine.

EcoMotors announced in March 2014 that it was delighted to have First Auto Works Jingye as a partner. A year earlier, in April 2013, EcoMotors signed a deal with Zhongding Power in China which is investing $200 million in facilities to make the opposed-piston engines. Executive chairman of EcoMotors International is Don Runcle, well known in the US for his long association with Delphi. EcoMotor claims a single module opposed-piston, two-stroke diesel engine with 100mm bore can develop 325bhp at 3,500 rev/min and 664lbft (900Nm) torque at 2,100 rev/min for a dry weight of 296lb (134kg) to give a power density of 1.1 bhp/lb. A Ford 4.4-litre V8 diesel, also with a CGI block delivers 335bhp and 516lbft (700Nm) torque. However, Runcle admitted they were not getting as much (performance) as they deserve.

Meanwhile, David Johnson, president and chief executive of opposed-piston engine developer Achates Power, is focused on changing attitudes about opposed piston engines in both passenger car and commercial vehicle segments around the world. Achates Power is perhaps the best known of the three US companies.

“It’s a little bit like hand-to-hand combat,” he is reported as saying. “You need to meet with every individual person who has a say in these large companies. I’m not selling to my neighbour, I’m selling to large corporations where decisions are made in committees, and lots of people have a say. Each and all of them need to be convinced of the data that we generate and the effectiveness of the solution.”

Johnson is nevertheless confident Achates has developed a lucrative solution to improving fuel economy, and believes that it is the right time for opposed-piston engines to reveal their advantages over more traditional ICEs.

Reverting to Pinnacle Engines, it seems the first step in its strategy is proving the opposed-piston engine’s merits in the scooter and motorcycle market, before using this success to convince automotive OEMs to invest. This is a route taking by other innovators, including Fallbrook with its continuously variable transmissions (CVTs) applied first to bicycles.

“We focused on scooters and motorcycles as a faster time to market,” explained Cleeves. “Our expectation is that success in scooters and small motorcycles will give us the credibility to enter the broader automotive market. In an automotive application, we will provide even better fuel efficiency gains for the same cost as the current downsized turbo GDSI engines. Cost sensitive markets like India, China, Indonesia and Africa will find this combination irresistible.”

Achates Power on the other hand is targeting the passenger car and commercial vehicle markets in parallel.

Achates Power’s Johnson has pointed to the fuel savings that can be made in CV fleet operations.

“Commercial vehicles use a tremendous amount of fuel per year – in the order of 20,000 gallons,” he is reported as saying. “We’re talking about millions of vehicles on the road. Now you’re talking about volumes that really drive the total consumption of fuel.”

“It’s coming,” he added. “Our customers will make the announcements about when products will be available, so it’s not really our place to do so, but I can tell you that based on the work we have been doing, it’s soon. Soon means within the decade, around 2020 – maybe before, maybe after. Certainly, going forward as the decade unfolds, we’ll see a lot of these engines used in applications around the world.”

On the other hand, this newsletter has come across a number of chief executives who glibly report that a particular technology “is coming” only for there to be major disappointments down the road.

So no one is holding their breath at the moment for opposed-piston engines.

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