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Is the no. of Cylinder the only criteria for a better diesel engine?

Discussion in 'Technical' started by Relativity, Jan 15, 2012.

  1. @ENKi
    Man you mean 'economical'.When it comes to v configuration diesels.They are economical but not that economical for us to afford.v config diesels are known as super diesels.These engines punch a lot of pulling power and a great deal of torque,they owe it to their design.v's are made to suit vehicles ,you just cant swap a punto mjd with a v6.These engines need heavier mounts and reinforced chassis,that would be burnimg the end users pockets:-D
  2. ENKI

    ENKI Esperto

    I have heard V4s & it was a typo above but never for V2-V3s. Thanks for correction though but one has to Google for V2-V3. I-4 & V-6, the most common configuration of cylinder arrangements. It's most used set-up as the basic & cheapest tradeoffs between NVH/space utilization in engines bay. Also V-8 are always smoother than V-6 because of even number of cylinder's in each arm of V. There are some drawbacks too with V6 & not with I-6 but again, it's a tradeoff for space as I-6 are very wide. Even among V-6 range, there is 60-90-120 deg. Makers keep on introducing something different & never know what could come out tomorrow. BMW is doing I-6 for their own reasons. FIAT have made 2.4 ltr I-5 JTD despite of "All straight engines with an odd number of cylinders suffer from primary dynamic imbalance, which causes an end-to-end rocking motion". That also explains why VW I-3 is a high voltage cable w.r.t MJD's. Thanks to the use of offset crank pins, counterweights, and flying arms which has reduced the problem to a minor second-order vibration in modern designs however.

    Yep the torque graph@rpm improves with increase in cylinders but hardly any gain in overall/Peak torque. Well by the way, i am not sure about how many people are aware but "Lancia introduced the first series production of V6 in 1950 in Lancia Aurelia". Italians have been godfather no matter what you talk for automobiles.

    ---------- Post added at 10:30 PM ---------- Previous post was at 10:12 PM ----------

    Nope, Engine's volume would be same. Investment to build an engine is in it's robotic facility/platform/DIYs. Once they are prepared, you can make any number's of cylinders you want. Yep, more investment would be required if you develop two separate platforms/DIYs etc. It's has to be done to limit dynamic or rocking properties.
    FYI, all FIAT engines (irrespective of they are Turbo Petrol & Diesels share the (BOREXSTROKE) & blocks. For eg. 1735 turbo petrol shares BORE with 1.6 MJD. 1.3 MJD shares stroke from 1.9 MJD. They can make it V6, I-4 MJD/Multiair whatever hell they want from the same resources. They found existing combination for their purpose so can't blame them. Pls compare specific O/P 1.6-MJD-2,I-4 (120 HP, 320NM) & 3.0-MJD2-V6 (242 BHP, 550 NM). Specific O/Ps favors 1.6 MJD-2, engine with lesser no. of cylinders. Yep, 3 ltr V6 will have a rather flat torque curve & torque will die late than 1.6 Mjd-2. That's why the big size maintain higher top speeds than their small counterparts with more power/torque.

    A better pseudo technical term, There shouldn't be an ODD Number of cylinders in arm whether the arm belongs to I-3 or V-6. If you care to note, V6s are actually two I-3s effectively arranged at an angle 60-90-120 degs, whatever preferred.
    1 person likes this.
  3. sungoa2010

    sungoa2010

    Messages:
    2,878
    Goa
    VW's is a late entry in CRDI technology. Their TDI PD engines (used in old Fabia,Octavia and old Laura) is a much noisy engines compared to the current ones.
  4. ENKI

    ENKI Esperto

    Sungoa, Background story is a bit interesting though. They tried their best not to opt for CRDI technology as it would make FIAT out and out Pioneer in Diesel engines. They tried their own concepts like "PUMP DUSE::pP" but never got the results.

    Same is happening in "Multiair case" too. For instance, FIAT 1368 cc Multiair Turbocharged against VW's 1398 cc Turbo Supercharged. It beats VW TSI winning 2010 international engine of the year too. Pls refer below stats.

    FIAT's 1368 cc multiair turbo: 170 BHP/250 NM, 50 MPG (combined) with CO2/Emission figure of 139gm/km
    VW's 1398 cc TSI supercharged: 160 BHP/230 NM, 45 MPG (Combined) with CO2/Emission of 152gm/km

    To match FIAT's consumption & emission figures (emission attracts environmental tax in Europe), VW has to down tune their engine by 65 HP i.e. only 95 BHP left;).
    That's what FIAT has made:). With snail like pace in Petrol engines in last 30 Yrs, Multiair simply outclasses any other technology in every aspect including cost too.

    They or any other manufacturer has to opt for it, no option & pay the royalty to FIAT. Multiair-2 launch due soon, their engines will be totally outdated compared to FIAT's. This time it's not a CRDI's suicide that FIAT is going to commit, FIAT Power-train chief, Alfered Atavillo have already challenged in 2011 that all the manufacturers have to opt it with-in next 4-5 Yrs.
  5. WELL then enki bhai, doesnt an extra set of pistons and a precision rebored engine block mean extra Cost.As for number of cylinders and the displacement,they also depend on the crank angle,angle of TDC and BDC of each cylinders wrt each other.There are engines starting from 45 to 180 degree angles,but the matter is cost of fabrication and fuel efficiency.No matter fiat can introduce it in the home range of linea and punto,but remember there needs to be a lot of changes to the chassis,like the chassis is to be reinforced to withstand vee config vibrations.Because these engines are known for their vibrations compared to inline SI engine.and in layman terms, the extra set of pistons means extra consumption of fuel for each complete cycle,though you pump a great deal of power and torque.

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