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JozNikos
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No longer have access to MTZ :( Check MTZ Issue Dec 2004 from Denger. I would be curious to see what different claims they make in term of fuel economy. All I can say 20% at low load is true, reducing pumping loop, but you have system doing the same, (valvetronic, multi-air, and some other system from Nissan and Honda). The reality in NEDC (WLTP don't know) would not be so glamorous. One fundamental challenge you are facing with those system on the exhaust valvetrain, is that you require way more force to open the valves, driving the efficiency of the overall system low. On top of it, with inherent cycle to cycle combustion variation, it is hard to control the valve trajectory on the exhaust, if you are operating those system as open loop. Bottom line, we haven't seen yet a use case which justify the add-on cost of such system.
It's a revival of Bosch EHVS, from the early-mid 2000 :) not quite Stone Age, but not far... funny to see a claim of innovation behind these concept... we should spend our R&D $$ and brain power on more sustainable solution, and low cost...
This system is more like what Audi released in 2008, AVS system in term of functionality, and pretty much in line with in term of performance gain and fuel economy as compared to what Audi introduced in '08. For turbocharged you can also add that system on exhaust, that can help reduce turbo lag and low end torque. Valvetronic would get you around 10% fuel economy and has more degree of freedom with the variable lift, and should be pricier for the manufacturer. Cost benefit of full variable valve train are getting trickier, as engine are getting downsized, and getting less pumping losses for gasoline engine.
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Jul 3, 2019