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Cooley On Cars
Car Tech 101: Opposed piston enginesBrian Cooley looks at opposed piston engines, how they work and why you should care about them.
[SOUND] [MUSIC] Most combustion engines in cars have rows of cylinders containing pistons that move up and down. Punching back and forth, toward or away from a Fixed cylinder head at the top. On the other end, the piston's connected to a crank shaft by a connecting rod. the opposed piston, opposed cylinder or opoc engine is quite different First, each cylinder has two pistons in it. Secondly, those pistons punch back and forth against each other rather than a cylinder head. One design by a company called EcoMotor puts the crank in the middle. The pistons connect to it by either a short connecting rod for an inside piston, or a longer connecting rod for an outside piston. Another design by Arcady powers connects each piston to one of two crank shafts at the outer edge of the engine and combines power from the two cranks for a set of gear. Both eco motor and Acadie use a two stroke engine design. That means an engine with fewer parts, that takes less room, and creates power every other time the piston moves verses every fourth time it moves like in your car. The engineering challenge though is that 2-strokes traditionally are dirty and burn a lot of oil. Another OPOC design from Pinnacle Engines tries to solve for that by being a four-stroke engine. All of these OPOC designs are different from the flat four and flat six engines you find in a Subaru or a 911. Those engines just lay out the cylinders in a flat array but they still use a single piston per cylinder and still work that piston against the face of a cylinder head. An interesting variant of the OPOC engine is one deployed as a linear generator where the two combustion driven pistons punch back and forth against each other, as we've seen but instead of turning a crank shaft, they slide spring loaded magnets back and forth to create electricity. You're likely to hear more about these engines in the last half of this decade, so here are four concepts to bare in mind. They are more thermally efficient because they don't have a head zapping cylinder head. They have double the number of pistons in a cylinder to peruse more power generating devices in less space. These are engines that seek to have fewer parts and therefore less waste. And their generally flat packaging is something car makers are interested in as opposed to small bulkier engines. More car tech [UNKNOWN] right now at CNETOnCars.com, click on car tech 101. [NOISE]