Dynamic Skip Fire Cylinder Technology To Make Gas Powered Vehicles As Clean As Non Cheating Diesels

Parts supplier Delphi and automotive tech company Tula have announced a new type of cylinder shut-off technology for petrol engines that is claimed to reduce CO2 emissions and fuel consumption by 8-15%, making petrol engines as clean as their diesel counterparts.

The dynamic skip fire cylinder deactivation system works by deciding whether to fire or skip each cylinder before its firing; if a cylinder is skipped, the intake and exhaust valves stay closed, with Delphi’s cylinder deactivation hardware holding them closed. The system works by controlling the car’s spark ignition, so only petrol cars are compatible.
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Dexter1 - 4/26/2017 3:16:17 PM

+1 Boost

Non-cheating diesels are the benchmark for combustion cleanliness?

TomM - 4/26/2017 6:38:24 PM

+1 Boost

Yes - there is something wrong with this story - the point of the diesel was low-end torque and fuel efficiency - but they emitted higher carbon particulate emissions. Why are they getting excited about making a ICE engine WORSE than they are today?

atc98092 - 4/26/2017 7:36:06 PM

+2 Boost

Current diesel emission controls make a diesel engine cleaner than almost ever gas powered engine. The only possible exception is NOx, and it's at the same level as gas engines. The term "non-cheating" simply refers to an engine that meets these standards without the now infamous cheat software.

Compared to modern gas engines, particularly direct injection models, a diesel has far fewer measurable particulates. My 2009 Jetta with 100,000 miles had a cleaner tailpipe than my 2012 Q5 2.0T with 75,000 miles. There was just that much less coming out the tailpipe. In fact, gas engines are soon going to have to install particulate filters, same as diesel engines, because they emit so much.

Dexter1 - 4/27/2017 12:52:46 AM

0 Boost

Thanks for explaining atc98092. You learn something new every day!

vdiv - 4/27/2017 3:36:59 AM

+2 Boost

How do they keep the valves closed when the piston is still moving and compressing air in each stroke? Wouldn't that create extra resistance? As Honda's variable cylinder deactivation has showed there is a limited benefit, but only on 6+ cylinder engines. If we have to have a piston engine I'd rather have a hybrid system where the entire engine shuts off, and when it runs it only does so in optimal mode.