Go Back   Team-BHP > Under the Hood > Technical Stuff


Reply
 
Thread Tools Search this Thread
Old 10th August 2017, 07:03   #1
Senior - BHPian
 
hserus's Avatar
 
Join Date: Sep 2014
Location: Chennai
Posts: 1,894
Thanked: 1,942 Times
Default Mazda plans a new engine using both - compression & spark ignition

https://www.topgear.com/car-news/fut...bustion-engine

The engine fires using both compression (like diesels) and spark plug (like petrol mills), not sure just how they managed that.

I wonder just what fuel air mixture and compression ratio adjustment they worked out to manage this and not have the engine catch fire.

What do we have here, an engine that behaves like a diesel if you fill diesel and like a petrol if you fill petrol? One that runs on half petrol half diesel?
hserus is offline   (7) Thanks Reply With Quote
Old 10th August 2017, 08:20   #2
Distinguished - BHPian
 
CrAzY dRiVeR's Avatar
 
Join Date: Jun 2006
Location: Bangalore / TVM
Posts: 8,974
Thanked: 16,767 Times
Default re: Mazda plans a new engine using both - compression & spark ignition

Quote:
Originally Posted by hserus View Post
What do we have here, an engine that behaves like a diesel if you fill diesel and like a petrol if you fill petrol? One that runs on half petrol half diesel?
Quite interesting and thanks for sharing.

From what I understand, it's a petrol engine that runs with very high compression ratios as seen in diesel engines. Usually, petrol engines run much lower compression ratios, or need high octane fuel when the compression ratios are increased (But still way short of the diesels) for more performance.

Without the high octane fuel, the fuel will just pre-ignite before reaching the compression stroke and that is bad for the engine.

Now Mazda claims to have developed a system which can monitor and fire the spark plugs and create a pre-ignition (which is now a part of the cycle rather than unintended) before it ignites under the full compression. Benefits include high torque and efficiency typical of high compression diesel engines, but with cleaner petrol emissions.

Sounds complex when it comes to fueling requirements and longevity of the things. My biggest doubt is how they have overcome pre-ignition and made it desirable, so to speak. Hope Mazda cracks it right.

Last edited by CrAzY dRiVeR : 10th August 2017 at 08:23.
CrAzY dRiVeR is offline   (5) Thanks Reply With Quote
Old 10th August 2017, 08:52   #3
Distinguished - BHPian
 
Join Date: May 2005
Location: KL
Posts: 4,680
Thanked: 3,508 Times
Default re: Mazda plans a new engine using both - compression & spark ignition

Quote:
Originally Posted by hserus View Post
https://www.topgear.com/car-news/fut...bustion-engine

The engine fires using both compression (like diesels) and spark plug (like petrol mills), not sure just how they managed that.

I wonder just what fuel air mixture and compression ratio adjustment they worked out to manage this and not have the engine catch fire.

What do we have here, an engine that behaves like a diesel if you fill diesel and like a petrol if you fill petrol? One that runs on half petrol half diesel?
Mazda is on a high with their Skyactiv Petrol and Skyactiv Diesels. They are thinking outside the box and have tumbled the box upside down so that their Diesels run lower compression and Petrols run higher compression But Skyactiv Diesels have/had a problem of engine oil dilution with Diesel and the oil level in the sump rising. Their solution was to change the dipstick Anyway hope the engines are reliable.
Sankar is offline   (1) Thanks Reply With Quote
Old 10th August 2017, 09:04   #4
Senior - BHPian
 
reignofchaos's Avatar
 
Join Date: Apr 2007
Location: Bangalore
Posts: 2,224
Thanked: 1,175 Times
Default re: Mazda plans a new engine using both - compression & spark ignition

This tech is very similar to what Merc and Ferrari (probably renault? not sure!) are using in F1 - Homogenous Charge Compression Ignition. A pure HCCI engine does not require spark plugs. However the ones being developed right now are still hybrids that use spark plugs. HCCI is used for cruising at low speeds while it shifts to spark plugs when under load such as when accelerating or running at high speeds.

However here they are more optimized for longevity and efficiency than outright power (though both power and efficiency are in a sense interrelated).

The primary advantage over conventional GDI engines is that the fuel burns better and with efficiencies approaching 55% in the ideal case - very similar to the efficiency of a diesel engine.

Many companies are looking at this tech for its potential benefits - VW, GM, Hyundai and now Mazda as it offers better combustion of the fuel with far less NOx emissions. The latter is essential to reach emission targets imposed by governments around the world.

Just like we saw a large scale shift from EFI naturally aspirated engines to GDI turbos in the automotive world in the last few years, the next shift would be to HCCI. Unlike downsizing though, this might offer real benefits.

Last edited by reignofchaos : 10th August 2017 at 09:12.
reignofchaos is offline   (6) Thanks Reply With Quote
Old 10th August 2017, 19:54   #5
Distinguished - BHPian
 
Join Date: Jul 2009
Location: Kolkata
Posts: 3,506
Thanked: 2,072 Times
Default Re: Mazda plans a new engine using both - compression & spark ignition

First the Miller cycle, and now HCCI (when others seem to have given up on it).
Working with the Wankel must have really built character at Mazda.

Regards
Sutripta
Sutripta is offline   (3) Thanks Reply With Quote
Old 12th August 2017, 11:17   #6
BANNED
 
Join Date: Jan 2014
Location: mum,lko,kolkata
Posts: 704
Thanked: 673 Times
Infractions: 0/2 (14)
Default Re: Mazda plans a new engine using both - compression & spark ignition

Quote:
Originally Posted by hserus View Post
https://www.topgear.com/car-news/fut...bustion-engine
The engine fires using both compression (like diesels) and spark plug (like petrol mills), not sure just how they managed that.
I wonder just what fuel air mixture and compression ratio adjustment they worked out to manage this and not have the engine catch fire.
What do we have here, an engine that behaves like a diesel if you fill diesel and like a petrol if you fill petrol? One that runs on half petrol half diesel?
Thanks for the update, hserus - the dividing lines between compression ignition / spark ignition is getting increasingly blurred! For one, the compression ratios are getting inverted and so are the performance characteristics - with diesels going up to 5200 rpm (http://www.mazda.com/en/innovation/t...iv/skyactiv-d/), with the gasoline engines giving comparative torque/power outputs & calorific inefficiencies, while their diesel counterparts are claiming particulate emissions comparable to their gasoline stablemates!

The best of all possible worlds indeed. For diesel addicts like me, it is music to the ears that significant engine weight reductions are in the pipeline, due to the lighter scantlings all round, including smaller crank pin/main bearing sizes - the domino effect from that reduced comp. ratio, resulting in reduced stress thresholds!

Well, alright, so there are a few hiccups too - cold start niggles and warm-up misfiring being the ones highlighted in the media releases - but where's the harm in keeping fingers crossed & hoping for the best! In this Utopian world, one can just hope that M&M and TM-JLR try to catch up as best they can!

Last edited by shashanka : 12th August 2017 at 11:24.
shashanka is offline   Reply With Quote
Old 12th August 2017, 11:32   #7
Distinguished - BHPian
 
sgiitk's Avatar
 
Join Date: Dec 2007
Location: Kanpur
Posts: 7,162
Thanked: 3,757 Times
Default Re: Mazda plans a new engine using both - compression & spark ignition

Quote:
Originally Posted by Sutripta View Post
First the Miller cycle, and now HCCI (when others seem to have given up on it).
Working with the Wankel must have really built character at Mazda.
I still miss the Wankels. Pollution and fuel consumption killed these ultra compact and smooth mills.
sgiitk is offline   (1) Thanks Reply With Quote
Old 8th September 2017, 09:18   #8
Senior - BHPian
 
hserus's Avatar
 
Join Date: Sep 2014
Location: Chennai
Posts: 1,894
Thanked: 1,942 Times
Default Re: Mazda plans a new engine using both - compression & spark ignition

Quote:
Originally Posted by sgiitk View Post
I still miss the Wankels. Pollution and fuel consumption killed these ultra compact and smooth mills.
Lovely article - from a Jalopnik journalist who is a trained automotive engineer - on his trip to the Mazda plant and a preview of the Skyactiv+ engine.

http://jalopnik.com/mazda-s-holy-gra...opnik_facebook
hserus is offline   Reply With Quote
Old 10th September 2017, 08:24   #9
Senior - BHPian
 
sumeethaldankar's Avatar
 
Join Date: May 2007
Location: Mumbai
Posts: 2,673
Thanked: 1,022 Times
Default Re: Mazda to Scrap Rotary Engines

Quote:
Mazda has developed a new gas engine that's far more efficient than existing motors.
The Skyactiv-X engine uses compression rather than spark to ignite the fuel-air mixture.
It can be used quickly and easily in existing Mazda vehicle designs without adding costs.
https://www.yahoo.com/finance/news/w...183036367.html

Mazda has come with a new type of engine which works on compression similar to Diesel engines to improve their fuel efficiency and meet emission regulations. Looks like this might turn out to be a electric car fighter if it manages to get more FE from regular gas engines.
sumeethaldankar is online now   (3) Thanks Reply With Quote
Old 11th September 2017, 11:01   #10
Team-BHP Support
 
navin's Avatar
 
Join Date: Mar 2004
Location: mumbai
Posts: 22,509
Thanked: 3,884 Times
Default Re: Mazda to Scrap Rotary Engines

Quote:
Originally Posted by sumeethaldankar View Post
Mazda has come with a new type of engine which works on compression similar to Diesel engines to improve their fuel efficiency and meet emission regulations. Looks like this might turn out to be a electric car fighter if it manages to get more FE from regular gas engines.
Here is a video on HCCI engines and Mazda's twist on it.


In effect there will be a spark plug but it wont be used except when required (too cold/hot).

The same presenter also explains why rotary engines are not as efficient as we thought they are

Last edited by navin : 11th September 2017 at 11:03.
navin is offline   (2) Thanks Reply With Quote
Old 11th September 2017, 11:34   #11
Senior - BHPian
 
extreme_torque's Avatar
 
Join Date: Feb 2005
Location: Melbourne
Posts: 3,546
Thanked: 1,317 Times
Default Re: Mazda to Scrap Rotary Engines

Quote:
Originally Posted by navin View Post
Here is a video on HCCI engines and Mazda's twist on it.
I think this one deserves an altogether new thread because this is a problem that none of the big car makers including the Germans could figure out. I have huge respect for Mazda for their combination of performance, reliability, quality and price. Here is a car maker which punches far above its weight when it comes to engineering stuff.

Last edited by Aditya : 21st October 2017 at 09:16. Reason: Deleting video from quote
extreme_torque is offline   (2) Thanks Reply With Quote
Old 25th September 2017, 05:12   #12
BANNED
 
Join Date: Jan 2014
Location: mum,lko,kolkata
Posts: 704
Thanked: 673 Times
Infractions: 0/2 (14)
Default Re: Mazda to Scrap Rotary Engines

Quote:
Originally Posted by extreme_torque View Post
I think this one deserves an altogether new thread because this is a problem that none of the big car makers including the Germans could figure out. I have huge respect for Mazda for their combination of performance, reliability, quality and price. Here is a car maker which punches far above its weight when it comes to engineering stuff.
+1 I'd just add another virtue to the list - tenacity & perseverance. When the rest of the competition had given up on the Wankel rotary, Mazda persevered & came up with some notable cars & came furthest in sorting out the gas sealing problems. One could also add their relatively recent success in the GDI application.
shashanka is offline   Reply With Quote
Old 20th October 2017, 09:21   #13
BHPian
 
im_srini's Avatar
 
Join Date: Sep 2006
Location: Portland
Posts: 956
Thanked: 368 Times
Infractions: 0/1 (5)
Thumbs up Re: Mazda to Scrap Rotary Engines

Quote:
Originally Posted by reignofchaos View Post
This tech is very similar to what Merc and Ferrari ( probably Renault ? not sure ! ) are using in F1 - Homogenous Charge Compression Ignition.
Cool video about F1 plugs
Who would've thought they moved the pre-combustion chamber into the spark-plug !

Quote:
Originally Posted by sumeethaldankar View Post
Looks like this might turn out to be a electric car fighter if it manages to get more FE from regular gas engines.
More likely the last gasp of the Otto 4-stroke gasoline engine, the takeover of the electrics is inevitable...
Quote:
Originally Posted by shashanka View Post
When the rest of the competition had given up on the Wankel rotary, Mazda persevered & came up with some notable cars & came furthest in sorting out the gas sealing problems.
True, the RX-7 & RX-8 still command high prices in the used-car market, but they do come with huge caveats about their thirst for fuel & major reliability issues.
That said, in my book it's their 4-rotor LMP 787s from the early 90's that're really spectacular, even more than their Wankel engined street cars.

On a side note, Suzuki, yes, very same maker of cars for "unsavvy people" made a Wankel-engined bike way back in the early 70's !

~

Last edited by im_srini : 20th October 2017 at 09:47.
im_srini is offline   (2) Thanks Reply With Quote
Old 24th October 2017, 05:42   #14
BANNED
 
Join Date: Jan 2014
Location: mum,lko,kolkata
Posts: 704
Thanked: 673 Times
Infractions: 0/2 (14)
Default Re: Mazda to Scrap Rotary Engines

Quote:
Originally Posted by im_srini View Post
On a side note, Suzuki, yes, very same maker of cars.... made a Wankel-engined bike way back in the early 70's !

One more feather in the cap for the Maruti owners club!

Last edited by ampere : 30th October 2017 at 13:00. Reason: Fixed quote tag
shashanka is offline   Reply With Quote
Old 29th October 2017, 17:23   #15
BHPian
 
Join Date: Jul 2016
Location: Rajkot
Posts: 30
Thanked: 26 Times
Default Mazda's 'Holy Grail' Skyactiv-X Engine.

As the majority of the automotive industry continues working toward an electrified future, Mazda appears to be making a bold attempt to save the internal combustion engine.

Mazda unveiled an innovative breakthrough dubbed the Skyactiv-X engine that the automaker claims to have the performance of a traditional gasoline engine as well as the torque and fuel-efficiency of a diesel-powered option. Mazda describes it as “the world’s first commercial gasoline engine to use compression ignition.”

Mazda’s new Skyactiv-X engine runs on gasoline yet functions like a diesel engine by using a technology the automaker calls Spark-Controlled Compression Ignition (SCCI). Essentially, the engine uses compression ignition to burn its fuel, while still relying on a spark plug to initiate this combustion. The engine promises up to 30-percent more torque and a 20-percent improvement in fuel economy, figures that can definitely be appreciated in an industry continuing to be influenced by growing fuel emission regulations.



Source: NY Daily News
Sparky is offline   (2) Thanks Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Ignition, Spark plugs and Plug Wires - Questions? S@~+#0$# Technical Stuff 8 10th December 2017 14:45
Nissan's new gamechanger: VC-T engine with 'variable compression ratios' RavenAvi The International Automotive Scene 17 30th September 2016 11:24
Anybody Using aftermarket ignition coil & plug wires? finetuning Modifications & Accessories 0 27th March 2006 22:41
MSD Spark Plug Wires & Ignition coil Kaizer Sozay Modifications & Accessories 11 16th December 2005 09:12
Heard of duel spark ignition? Shan2nu Technical Stuff 1 15th July 2004 16:25


All times are GMT +5.5. The time now is 03:51.

Copyright ©2000 - 2017, Team-BHP.com
Proudly powered by E2E Networks