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<blockquote data-quote="Babagounj" data-source="post: 2742479" data-attributes="member: 12952"><p><a href="http://www.motortrend.com/news/at-least-one-automaker-plans-to-produce-an-opposed-piston-engine/" target="_blank">At Least One Automaker Plans to Produce an Opposed-Piston Engine - Motor Trend</a></p><p></p><p>During industry days at the 2017 North American International Auto Show, CEO David Johnson announced that by 2018 Achates would produce a drivable prototype truck powered by a 2.7-liter 270-hp, 479-lb-ft supercharged turbodiesel OP-3 engine capable of complying with Tier 3, LEV III, Euro 6 emissions while exceeding <a href="http://www.motortrend.com/news/epa-relaxes-54-5-mpg-corporate-average-fuel-economy-2025/" target="_blank">2025 CAFE standards</a> (its projected EPA label values will be 25/32/28 mpg city/highway/combined, yielding a 37-mpg unadjusted CAFE figure when 33 is the requirement for trucks with a footprint of 65-70 square-feet). Johnson further claimed that it would be 30 percent more efficient than the best diesel engines of comparable output, and 50 percent thriftier than the best similar gas engines. But the bigger bombshell was his announcement that of the nine automakers who have signed on as development partners, at least one of them has begun tooling up to build an opposed-piston engine in volume.</p><p><span style="font-size: 15px"><strong>Why it’s Efficient:</strong></span></p><ul> <li data-xf-list-type="ul"><strong>Thermal efficiency:</strong> Low ratio of combustion-chamber surface area to cylinder swept volume and elimination of cylinder head mean there’s much less heat rejected to the cooling system so more of the heat of combustion goes to propelling the vehicle.</li> <li data-xf-list-type="ul"><strong>Lower friction:</strong> With no cylinder head bolts to distort the bore, there’s less ring friction, and the lower peak operating speed of any compression-ignition engine lowers friction.</li> <li data-xf-list-type="ul"><strong>Lower pumping work:</strong> Intake and exhaust enter and leave via ports arranged around the cylinder at the top and bottom of the pistons’ strokes, so the pistons do no pumping work. With some of these ports open at all times on an engine with three or more cylinders, the supercharger and turbo also operate more efficiently.</li> <li data-xf-list-type="ul"><strong>Lighter weight:</strong> Lower cylinder pressures mean that even the diesel doesn’t need to be “hardened” to the same extent as a conventional four-stroke diesel.</li> </ul><p><span style="font-size: 15px"><strong>Why Emissions are Reduced:</strong></span></p><ul> <li data-xf-list-type="ul"><strong>Cooler operation:</strong> Lower peak cylinder pressures and temperatures reduce the amount of NOx and other pollutants produced in the cylinder.</li> <li data-xf-list-type="ul"><strong>Horizontal direct injection:</strong> Two fuel injectors spray across the cylinder instead of onto the hot pistons, which can cause the quenching that leads to particulate formation. Also, the stroke is long enough to fully burn the hydrocarbons.</li> </ul><p><span style="font-size: 15px"><strong>Why Costs are Lower:</strong></span></p><ul> <li data-xf-list-type="ul"><strong>Simpler assembly:</strong> Eliminating the cylinder head, valvetrain, and the machining thereof gets partially offset by the addition of a second crankshaft and the gears connecting the cranks, but overall assembly should be simpler. Also note that the Achates design requires only minimal retooling of existing engine plants.</li> <li data-xf-list-type="ul"><strong>Reduced cooling needs:</strong> Since it throws off less heat, the cooling system can likely be downsized.</li> <li data-xf-list-type="ul"><strong>Fewer emissions to control: </strong>Cleaner engine-out emissions allows all catalysts to be downsized and/or their precious-metal loading to be reduced.</li> <li data-xf-list-type="ul"><strong>Broad torque curve:</strong> With a broad range of torque and engine efficiency, it is less crucial to invest in nine- or 10-speed transmissions.</li> </ul><p></p><p><strong>Bottom line:</strong> Achates claims that meeting 2025 CAFE regulations with this engine will cost about $1,000 less than doing so by further modifying and/or electrifying the current crop of engines. This should allow manufacturers to meet the more stringent standards without forcing customers to “pay for fuel economy” they don’t care about with cheap gas, and without forcing them to compromise on their vehicle’s size or capability. Meeting regulations further out into the future can be done by applying current technologies like 48-volt electrification to the Achates engine. </p><p></p><p></p><p></p><p><a href="http://www.motortrend.com/staff/frank-markus/" target="_blank"></a></p><p><a href="http://www.motortrend.com/staff/frank-markus/" target="_blank"></a></p><p><a href="http://www.motortrend.com/staff/frank-markus/" target="_blank"></a></p></blockquote><p></p>
[QUOTE="Babagounj, post: 2742479, member: 12952"] [URL="http://www.motortrend.com/news/at-least-one-automaker-plans-to-produce-an-opposed-piston-engine/"]At Least One Automaker Plans to Produce an Opposed-Piston Engine - Motor Trend[/URL] During industry days at the 2017 North American International Auto Show, CEO David Johnson announced that by 2018 Achates would produce a drivable prototype truck powered by a 2.7-liter 270-hp, 479-lb-ft supercharged turbodiesel OP-3 engine capable of complying with Tier 3, LEV III, Euro 6 emissions while exceeding [URL='http://www.motortrend.com/news/epa-relaxes-54-5-mpg-corporate-average-fuel-economy-2025/']2025 CAFE standards[/URL] (its projected EPA label values will be 25/32/28 mpg city/highway/combined, yielding a 37-mpg unadjusted CAFE figure when 33 is the requirement for trucks with a footprint of 65-70 square-feet). Johnson further claimed that it would be 30 percent more efficient than the best diesel engines of comparable output, and 50 percent thriftier than the best similar gas engines. But the bigger bombshell was his announcement that of the nine automakers who have signed on as development partners, at least one of them has begun tooling up to build an opposed-piston engine in volume. [SIZE=4][B]Why it’s Efficient:[/B][/SIZE] [LIST] [*][B]Thermal efficiency:[/B] Low ratio of combustion-chamber surface area to cylinder swept volume and elimination of cylinder head mean there’s much less heat rejected to the cooling system so more of the heat of combustion goes to propelling the vehicle. [*][B]Lower friction:[/B] With no cylinder head bolts to distort the bore, there’s less ring friction, and the lower peak operating speed of any compression-ignition engine lowers friction. [*][B]Lower pumping work:[/B] Intake and exhaust enter and leave via ports arranged around the cylinder at the top and bottom of the pistons’ strokes, so the pistons do no pumping work. With some of these ports open at all times on an engine with three or more cylinders, the supercharger and turbo also operate more efficiently. [*][B]Lighter weight:[/B] Lower cylinder pressures mean that even the diesel doesn’t need to be “hardened” to the same extent as a conventional four-stroke diesel. [/LIST] [SIZE=4][B]Why Emissions are Reduced:[/B][/SIZE] [LIST] [*][B]Cooler operation:[/B] Lower peak cylinder pressures and temperatures reduce the amount of NOx and other pollutants produced in the cylinder. [*][B]Horizontal direct injection:[/B] Two fuel injectors spray across the cylinder instead of onto the hot pistons, which can cause the quenching that leads to particulate formation. Also, the stroke is long enough to fully burn the hydrocarbons. [/LIST] [SIZE=4][B]Why Costs are Lower:[/B][/SIZE] [LIST] [*][B]Simpler assembly:[/B] Eliminating the cylinder head, valvetrain, and the machining thereof gets partially offset by the addition of a second crankshaft and the gears connecting the cranks, but overall assembly should be simpler. Also note that the Achates design requires only minimal retooling of existing engine plants. [*][B]Reduced cooling needs:[/B] Since it throws off less heat, the cooling system can likely be downsized. [*][B]Fewer emissions to control: [/B]Cleaner engine-out emissions allows all catalysts to be downsized and/or their precious-metal loading to be reduced. [*][B]Broad torque curve:[/B] With a broad range of torque and engine efficiency, it is less crucial to invest in nine- or 10-speed transmissions. [/LIST] [B]Bottom line:[/B] Achates claims that meeting 2025 CAFE regulations with this engine will cost about $1,000 less than doing so by further modifying and/or electrifying the current crop of engines. This should allow manufacturers to meet the more stringent standards without forcing customers to “pay for fuel economy” they don’t care about with cheap gas, and without forcing them to compromise on their vehicle’s size or capability. Meeting regulations further out into the future can be done by applying current technologies like 48-volt electrification to the Achates engine. [URL='http://www.motortrend.com/staff/frank-markus/'] [/URL] [/QUOTE]
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