CX-5 - Mazda-Miller cycle engine

[CC58]

Saw this detailed description of the CX-5 Skyactiv engine. Interesting that it runs open throttle on light loads to increase efficiency. Maybe they will have gas engine without spark plugs next year.

http://wardsauto.com/vehicles-amp-technology/how-mazdas-skyactiv-fuel-efficiency-technology-works
One other contributor to the engine's efficiency is that it cruises open-throttle at light loads. "It actually runs with the throttle open almost like an Atkinson cycle," Coleman says. Other companies are doing this as well, but we're more picky about the details. We call it the Mazda Miller Cycle, because the Miller Cycle is our method of obtaining an Atkinson Cycle."

And clearly, Mazda looks at its current high compression ratios as just a start. During development, engineers were experimenting with 15:1 and even 18:1 compression ratios.

Eventually there will be some type of convergence between diesel and gasoline engines, with the ultimate goal to bring homogeneous charge compression ignition into the equation. That is everyone's Holy Grail, Coleman says.

 

[pjensen641]

Miller cycle uses a supercharger, Atkinson does not. True, the sky-activ is actually not purely Atkinson, but I would say its closer than it is to Miller. Interesting article, but I wonder about the accuracy of some of the statements. A little research says that Mazda DID produce a Miller cycle engine for the Millenia back in the 90's, which did have a supercharger.

http://en.wikipedia.org/wiki/Miller_cycle

 

[CX-SV]

I think these Skyactiv gasser engines are the only non-hybrid engines using Atkinson cycle.

Note: Today I'm driving a Lexus loaner CT200 hybrid, it has Atkinson cycle.

 

[paris1]

View attachment 207381View attachment 207382Note: Today I'm driving a Lexus loaner CT200 hybrid, it has Atkinson cycle.

I've always thought that was a gorgeous 5 door. The power train does nothing for me though. How are you finding it overall? Basically a Prius in disguise, right? Or a Camry hybrid? (Or are those both the same chassis?)

 

[CX-SV]

I've always thought that was a gorgeous 5 door. The power train does nothing for me though. How are you finding it overall? Basically a Prius in disguise, right? Or a Camry hybrid? (Or are those both the same chassis?)

I'm not especially fond of the exterior styling, but the interior finish is first class. Back seat is a little small and so is the trunk. It's slow like our 2.0L CX's but if the mpg is close to 40mpg, that's pretty good. Handling (and ride a bit harsher too, stiffer than I expected) is firmer than my CX-5 GT. I may have the car overnight, my Lexus IS is in for oil change and VVT actuator recall.

It's nicer to drive than the current gen Prius (I drove a Prius for a week in Canada a couple years ago.). I think it's more closely related to the Prius from what I read earlier...

 

[paris1]

I'm not especially fond of the exterior styling, but the interior finish is first class. Back seat is a little small and so is the trunk. It's slow like our 2.0L CX's but if the mpg is close to 40mpg, that's pretty good. Handling (and ride a bit harsher too, stiffer than I expected) is firmer than my CX-5 GT. I may have the car overnight, my Lexus IS is in for oil change and VVT actuator recall.

It's nicer to drive than the current gen Prius (I drove a Prius for a week in Canada a couple years ago.). I think it's more closely related to the Prius from what I read earlier...

It rides pretty low, so it doesn't surprise me that it gives up something in suspension compliance.

 

[CX-SV]

It rides pretty low, so it doesn't surprise me that it gives up something in suspension compliance.

Yes, just a bit less compliant with a touch more road noise on coarse surfaces. This particular CT has 13K miles on it and is in good condition.

One notable advantage is the lack of audible 4 cylinder thrashing noise at higher revs, it's better isolated at rpms in 4000+ range.

 

[Chris_Top_Her]

miller cycle supercharger from millennia on cx-5 go

 

[CX-SV]

Seems like in the quest for better fuel efficiency, superchargers in mainstream cars are going away. Turbochargers, yes.

 

[dad of jon]

Seems like in the quest for better fuel efficiency, superchargers in mainstream cars are going away. Turbochargers, yes.

in the uk the nissan micra's and note's top economy petrol (gasoline) model has a supercharger, also vw group has tsi models which have both turbo and superchargers. yes turbos are more common but superchargers are still being used. My next small car could well have a supercharger on it.

 

[CX-SV]

in the uk the nissan micra's and note's top economy petrol (gasoline) model has a supercharger, also vw group has tsi models which have both turbo and superchargers. yes turbos are more common but superchargers are still being used. My next small car could well have a supercharger on it.

In the US, turbos are growing in popularity, superchargers going down in popularity. Superchargers are still used, mostly in expensive cars.

 

[dad of jon]

in Europe because of fuel prices the our engines have less c.c. on average than the USA so we bolt more stuff on. Dont vw offer a TSI in the states? Skoda (vw group make) sell a tsi starting at 12,150

 

[erhayes]

Superchargers historically take a lot of power to drive one. Modern engines using superchargers, use a bypass system that allows the SC to pump only when extra power is needed. I believe Mercedes Benz was the first to engineer this type of system. Ed

 

[paris1]

Dont vw offer a TSI in the states? Skoda (vw group make) sell a tsi starting at 12,150

Yes, from the looks of their US website, all of their gas engines are TSI.

 

[CX-SV]

Yes, TSI on VW US gas engines. Do any of these US engines have twin charging (turbo and super charging)?

Note: Not all TSI engines are twin charged, some are DI and turbocharged only.

 

[Chris_Top_Her]

Yes, just a bit less compliant with a touch more road noise on coarse surfaces. This particular CT has 13K miles on it and is in good condition.

One notable advantage is the lack of audible 4 cylinder thrashing noise at higher revs, it's better isolated at rpms in 4000+ range.

I always looked at that car and thought there should be a "speed" version lol

 

[dad of jon]

Yes, TSI on VW US gas engines. Do any of these US engines have twin charging (turbo and super charging)?

Note: Not all TSI engines are twin charged, some are DI and turbocharged only.

Yes, as indicated by VW.

http://www.volkswagen.co.uk/technology/petrol/tsi

my Mazda twin turbo 2.2 diesel goes about providing great performance a different way to VW. Although the TSI's narrow the gap re: diesel vs petrol performance it's still not enough on this type of car.

http://www.youtube.com/watch?v=FzTnP-DQX48