While cylinder deactivation is hardly commonplace in modern engines, it's certainly not unheard of, especially from automakers hoping to eek out a little better fuel economy from larger displacement mills. It's not just for pickup trucks either; Lamborghini and Mercedes-Benz both shut down cylinders as a solution in some of their vehicles. However, automotive supplier Schaeffler thinks that there might be a reason to bring the tech to some of the smallest engines on the market – namely, three-cylinders.

Don't laugh just yet. According to Ward's Auto, Schaeffler has adapted its cylinder deactivation tech for inline-three engines. When less power is needed, the equipped threes would run with just two cylinders firing.

In some ways, the odd notion of cruising around with just an inline-two makes some sense. With the current technology, each group of valves to be deactivated needs its own roller finger followers (pictured above). While an automaker might need four sets of these components for a V8, it would only need one for an inline-three. That makes it a lot cheaper to implement.

The glaring problem with Schaeffler's design is that the gains from cylinder deactivation for such small engines aren't exactly huge. These aren't gas-guzzlers, after all. The company claims that the technology boosts economy by at least three percent – every little bit helps, though.

Autoblog reached out to Schaeffler for more information on the cylinder deactivation for inline-three engines, but the company had no comment "due to customer agreements."


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  • 26 Comments
      Actionable Mango
      • 5 Months Ago
      Deactivate all three cylinders for a whopping 100% gas savings!
      2 wheeled menace
      • 5 Months Ago
      Um... sounds useless to me, and may involve a disbalance of the engine.. you can reduce pumping losses with transmission instead if you're really looking to eke out more fuel economy from an engine that already has putzy output.
      Cruising
      • 5 Months Ago
      Sounds like it could be useful for small city cars like the Smart.
      • 5 Months Ago
      @Chris Bruce- The expression is "Eke out" not eek out. Eek! Is used when someone is surprised.
      jeby
      • 5 Months Ago
      1983 - Alfa Romeo Alfetta 2000 C.E.M., it has a 4 cylinders that can deactivate 2 cylinders. They've built 991 of them, then realized that a lot of Italian were able to autonomously deactivate a variable number of cylinder during normal operation. XD
      skrr123
      • 5 Months Ago
      The problem with trying this with an in-line 3 cylinder engine is that the off-set of the crankshaft journals would need to change--not just the timing--in order to not lose efficiency. While this is possible, it is also more mechanically complex--raising cost to manufacture and repair. A better way to go would be to develop liquid piston technology and apply it to a rotary engine.
      Doug Danzeisen Sr
      • 16 Days Ago
      Hmmm, could this apply to the Elio?  They are developing a 3 cyl engine similar to the Old Suzuki Metro engine with updated tech. Keep an eye on this one.
      asdf
      • 5 Months Ago
      This engine shall be named the Obummer
      jbm0866
      • 5 Months Ago
      So... Go from low power to almost no power awesome
      carguy1701
      • 5 Months Ago
      wat seriously?
      Bernard
      • 5 Months Ago
      Instead of that, why not just make a PHEV where the gas engine doesn't connect to the drive train? That would be cheaper and more fuel efficient. Or you could take the next step and just buy an EV.
        Card13
        • 5 Months Ago
        @Bernard
        How is implementing any electric propulsion system cheaper than a tiny gas engine?
        erjhe
        • 5 Months Ago
        @Bernard
        I think largely because a well geared transmission is going to be more efficient than a generator/motor combo. You can argue that such a setup could always keep the engine at the optimum RPM, but so can an CVT or any other transmission with the correct gear ratios for the application.
      jebibudala
      • 5 Months Ago
      Eventually there will be a point of diminishing returns. It would cost $XXX to implement this technology, along with start-stop, and you'll only get 1-2% return tops on such a small displacement/fuel efficient engine. It would take hundreds of years to get your ROI, whereas this technology on larger less efficient engines would make more sense. For example start/stop on a 1.0L ecoboost 3 cyl is pointless since it uses such tiny amounts of fuel during idle anyway, in trade the cons of having a MUCH larger and heavier battery, starter, and alternator, you'd probably consume as much, if not more fuel hauling the extra weight around to support the fuel savings system. Now, if Americans can just shed 20 lbs from their body mass, that'll probably give better fuel savings than any of these technologies.
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