Cylinder Deactivation Could Drop a Corvette Down to 2 Cylinders

by Aaron Cole

Updated: December 31st, 2020 Published: September 16th, 2015

General Motors may use an advanced cylinder deactivation technology, co-developed with Delphi and Silicon Valley startup Tula Technologies, in its SUVs and V-8 cars to shut down up to six cylinders to maximize fuel economy, Automotive News reported.

According to the automaker, GM in 2012 invested in Tula, which specializes in automotive engineering. The automaker announced in January that it would pursue the advanced cylinder deactivation technology for some of its SUVs, which could improve fuel economy by 15 percent in cars with engines with more than four cylinders.

The system, dubbed Dynamic Skip Fire, keeps the throttle open during operation and controls cylinder firing through a special valve that cuts off oil to the deactivated cylinders’ valve lifters. According to the company, the engine computer changes the deactivated cylinders to avoid vibration or noise.

According to the report, a GMC Yukon Denali with a 6.2-liter V-8 was fitted with DSF to shut down all but two cylinders on a highway drive. The Yukon’s fuel economy improved by 21 percent, according to Automotive News.

“This technology holds the potential to improve fuel economy on select GM vehicles without degrading power capability when it’s required,” Jon Lauckner, GM chief technology officer, vice president of Global R&D and president of GM Ventures, said in a statement.

The cost could be between $300 and $600 depending on the engine for the technology.

#CylinderDeactivation #Delphi #Denali #DynamicSkipFire #GeneralMotors #TulaTechnology #Yukon

Aaron Cole

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14 of 88 comments

Sgeffe on Sep 16, 2015

Did I read the article correctly that the ECU would vary which physical cylinders are shut down? (IOW, when a V8 goes to 4 cylinders, it's not the same four that shut down every time.) That would stop the oil-burning and other issues. NVH is still going to be a problem, but I can deal with a little growl when I can go at Vmax with A/C blowing ice cubes and 2 pax aboard, and still pull mid-30s on an N/A SOHC V6!

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- EAF on Sep 16, 2015
  
  Good point, I misread the article. On a V8, if any 2cyl can be strategically activated, it would make sense that issues with oil consumption could be eliminated. It would also follow that NVH levels, when compared to AFM, would benefit greatly as well. No more turbos in 2017? Lol
  
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Synchromesh on Sep 16, 2015

Tula is actually a large city in Russia which houses a major armament complex. Considering Corvette designer's Russian roots I suppose it makes sense.

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Master Baiter on Sep 16, 2015

Here's an idea: use the de-activted cylinders as an air compressor. On deceleration and braking, store the compressed air in a tank. Release the air in the tank back into the cylinders on acceleration to supplement gasoline power.

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- EAF on Sep 16, 2015
  
  True. Or if GM could harness the power contained in a bolt of lightening, and somehow channel this power into the flex capacitor. The problem is you can never accurately predict when or where such a strike will occur. :-)
  
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- Redav on Sep 17, 2015
  
  Or, it when full engine load isn't needed, it could run a generator and store electricity, then when more power is needed, that generator is a motor to provide extra torque.
  
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- KixStart on Sep 17, 2015
  
  @redav "Or, it when full engine load isn’t needed, it could run a generator and store electricity, then when more power is needed, that generator is a motor to provide extra torque." Do you know you're describing a hyrbrid or are you being unintentionally ironic?
  
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DenverMike on Sep 16, 2015

This is just more proof what a stup!d concept the Eco Boost V6 was, as far as replacing V8s. Here's a V8 that's more fuel efficient than the EB, more powerful, more compact, and weighs at least 100 lbs less. I'm baffled as to why we're so obsessed with cylinder count and displacement.

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- Rudolph on Sep 17, 2015
  
  Cylinder count & displacement Decades ago the GMC I6 truck engine (302 cu in) was used in oval dirt track races - unbelievable torque for the time ‼
  
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- Redav on Sep 17, 2015
  
  I get the idea behind govts taxing displacement, but with forced induction, those govts look like a special kind of dumb. (Want a 5L engine making 300+ hp? Get prepared to take it up the tailpipe in taxes. Want a 2L turbo making 300+ hp and getting the same mpg? Great!) Cylinder count is a more logical issue. The more cylinders, the more internal engine drag, so fewer cylinders should mean more efficiency. But when "should" doesn't overlap "does," it's time to stop talking about it.
  
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- KixStart on Sep 17, 2015
  
  "Here’s a V8 that’s more fuel efficient than the EB, more powerful, more compact, and weighs at least 100 lbs less." According to the GM Press Release. Similar documents have also described other GM wonders that didn't quite work out in the real world.
  
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- 28-Cars-Later on Sep 17, 2015
  
  @redav You make good points but to me mileage should be the primary issue, not size. It seems people with no size themselves are always concerned about the size of others.
  
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- Sigivald on Sep 17, 2015
  
  @KixStart Well, I think we can trust them on power and packaging [after all, we know how bit their engines are, and adding deactivation shouldn't change the size or significantly affect weight]. The only qualm will be on the fuel economy.
  
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- DC Bruce on Sep 17, 2015
  
  @Sigivald A site called "the fast lane truck" ran a Ford Ecoboost pickup pulling 10,000 lbs. of trailer up the I-70 grade from Silverton to the tunnel at the top and also ran a Chevy 6.2 8-speed pulling the same load. IIRC, the Chevy did a little better than the Ford in fuel consumption and basically the same speed (the 65 mph speed limit). Pickup trucks.com ran a more carefully controlled test over a 100 mile loop in Michigan; and the 6.2-powered trucks were several mpg better than the 3.5 liter Ecoboost -- and this was running empty. As is well known by now, the Ecoboost engines generally seem to have disappointing fuel economy in owners' hands, as compared to their EPA ratings.
  
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