- Thread starter ssun30
- Start date
You are not supposed to. NDAs exist for a reason...
https://newsroom.toyota.co.jp/en/powertrain/tnga/
One of the pictures show that their Dynamic Force engine's number of cylinders start from 4, not sure if that picture is accurate.
One of the pictures show that their Dynamic Force engine's number of cylinders start from 4, not sure if that picture is accurate.
From 2006: https://www.tytlabs.com/english/review/rev413epdf/e413_001uchida.pdf
https://www.tytlabs.com/english/review/rev413e.html
Does anyone know when downsizing started? Toyota is surprisingly the last company to get in. I understand that hybrid was an alternative to diesels,
https://www.tytlabs.com/english/review/rev413e.html
Does anyone know when downsizing started? Toyota is surprisingly the last company to get in. I understand that hybrid was an alternative to diesels,
TL;DR: Toyota didn't rush to join the downsizing revolution because 1) they had very good naturally aspirated engines 2) they already have the most efficient solution (hybridization). When you don't have to turbocharge, you don't add turbochargers, there is no replacement for displacement.
Downsizing is the way of the future. That future is not here yet, but almost. It makes sense to start preparing now, and that's what the relatively underwhelming 8AR-FTS and 8NR-FTS are for.
Now to the long part. Downsizing started with the BMW N54, but the one that pushed it to the mainstream was the VW EA113 TFSI. Turbocharging their Inline-6s was the logical move for BMW since a 3.0L+ unit would be too long. Remember these were the times that large displacement Japanese V6s dominated the premium market with their beastly 280hp+ 3.5L units. Few remember that the XV40 ES350 was once the world's fastest FWD car in a straight line, and that the RAV4 V6 was the fourth fastest SUV behind the Porsche Cayenne Turbo, VW Touareg W12, and BMW X5 46is. The three best engines of 2006 in terms of performance-efficiency balance was 2GR-FSE and VQ35HR followed by N54B30. But the N54 had some questionable reliability records.
What enabled downsizing to become a reality was direct injection. Pre-downsizing era turbos were very inefficient because they have to run very low compression ratios, very rich mixtures, and/or high octane fuel to prevent knocking. Direct injection gave automakers the necessary 'free octane' to run meaningfully efficient engine maps. But the benefit was fair to everyone: naturally aspirated engines also got the free octane and ran very high compression ratios. The rule in auto engineering is that if you don't have to turbocharge, you don't add tubochargers because they are just extra cost. So that's what Toyota did.
The main incentive for German automakers to go for downsizing early was a political one. They conveniently took advantage of NEDC that gave an unfair advantage to downsized motors. They then used their political influence to lobby the Chinese government to adopt a similar cycle and basically drove all naturally aspirated competitors out of the country with the Displacement Tax. They finally completed the takeover of the world's largest auto market by forcing local automakers to join the supply chain. Many local chinese automakers have to use turbocharged engines made by German suppliers because they are 'bundled' with other crucial technologies the nation is desperate for. I have to say I hate German brands because of their takeover of my country's auto industry; it's Economic Colonialism.
Another reason to not turbocharge is exactly what you said: hybridization. Like the turbocharger, electric motors also provide downsizing, downspeeding, and recovery of waste energy, but they also enable load shifting which was a game changer. The efficiency you gain from hybridization was much, much more than what you will ever get from turbocharging alone. They never tried turbo-hybrid because it just made no sense. The point of load shifting was operating the ICE at the optimal thermal efficiency, so it's counter-productive to use a turbocharged engine that has lower maximum thermal efficiency. Turbo-hybrids will eventually come, possibly on the next-gen Prius, when more exotic technologies like variable compression and camless heads become economically feasible. I will say with confidence that TMC will commit to downsizing starting from Dynamic Force 2.0 but that's for 2025. We see Nissan already taking a head start this year with the wonderful VC-T (though the transmission choice is just plain stupid), but it will take time for that technology to trickle down.
I should clarify here that with the same fuel octane, same power target, and same underlying design elements, a turbocharged downsized engine will always have lower maximum thermal efficiency than a comparable naturally aspirated engine. This is because turbocharging increases the knock tendency so the engine will have to run at lower CR, more retarded ignition timing, richer fuel mixture or a blend of the three. But in real world the downsized engine will possibly (note I say possibly) have better fuel efficiency because it tends to operate at a more efficient point. I know this could be somewhat hard to understand, but there are some very intuitive visual explanation of how downsizing shifts engine operating point to optimize efficiency on the Internet.
Last edited:
^^Ten years ago, Chinese automakers couldn't make an automatic gearbox with more than four gears, so they asked for help, and the Germans showed up with the DSG. As a result no local automaker can make a profit without cutting corners on safety because of overpriced engines and transmissions. Now they have to buy overpriced safety packages from the Germans again and it just becomes a downward spiral. Now you see why China is desperately going for electrification as a way out of this economic colonialism.
Last edited:
The GR engine was just as good compared to rivals back then and remains competitive even now. The 'issue' is that TMC was and is always about products that sell based on their objective measures and merits rather than products that sell based on consumer's perception created by aspirational marketing strategies.
In terms of engineering know-how and excellence, TMC is very competent, if not the most.
In terms of engineering know-how and excellence, TMC is very competent, if not the most.
CIF
Premium Member
- Messages
- 1,675
- Reactions
- 1,825
You're right about one thing. When taking about gas engines, there is no replacement for displacement. Not to go too off topic here, but much of your post is contradictory. You correctly admit that downsizing for the Germans was mostly political, yet you say downsizing is the future without showing any concrete evidence for this. Just because some automakers are downsizing does not make it the future. Some automakers currently downsizing are doing it for mostly political or regulatory reasons, that's it. Laws or taxes in some countries require downsizing, but this has been true for many, many years in those countries. However speaking about North America, there are no laws or taxes on displacement. There is a gas guzzler tax in the US for bad fuel economy, but this is not directly tied to displacement and can be mitigated (and has been mitigated by various automakers) by many technologies and innovations. The political and regulatory aspects are very much up in the air in North America right now. Also the fact is most customers have not been asking for downsized engines. This is especially true for USA. In America many people still like large displacement, smooth and high torque engines.
I'm no engineer, but I know enough and have driven enough turbo vehicles to know that real world fuel economy suffers a lot with turbo gas downsized engines due to a number of physics principles. Large displacement turbo gas engines don't suffer as much. The vast majority of turbo downsized gas engines were made to defeat regulatory and environment lab testing (without much concern for real world fuel economy), not because there is customer demand for them. Turbo diesel downsized engines are different, but diesel technology is on its way out for most passenger vehicles worldwide.
Regarding future Dynamic Force engines, I really would not jump to conclusions or make such confident proclamations that you are doing. The 8AR and 8NR are not Dynamic Force engines. So far there is absolutely zero evidence, or even zero hints that Toyota wants to downsize with future Dynamic Force engines. So for, the V35A and A25A are not downsized at all. While some may argue the V35A replaces a V8 in the LS, the LS may still receive a new V8 in the coming future. Also the V35A has the same displacement as Toyota's 2GR engine. Furthermore the V35A seems to be large exception in the overall Dynamic Force lineup. Toyota's powertrains are currently in a big state of change. The M20A, being the new global 4 cylinder engine, is not only not downsized, it has been upsized compared to the 2ZR. Toyota in technical documents officially compares the M20A to the 1.8L 2ZR. The key philosophy of Dynamic Force engines includes the principles of high thermal efficiency, world class thermal management, high performance, high response, and low emissions. Downsizing and turbocharging directly conflicts with some of the key Dynamic Force principles. Also Dynamic Force documents and recent statements by Toyota officials heavily imply that Toyota will meet future political and regulatory requirements through a combination of Dynamic Force and TNGA technologies and increased hybridization and electrification, not downsizing and turbocharging.
Unless you are willing to share and directly provide some insider information from Toyota Japan, then no, you cannot say anything "with confidence" regarding Toyota possibly committing to downsizing in the future. To say anything with confidence without direct and concrete proof is misleading and inaccurate. The public evidence we have so far from Toyota says they won't be downsizing in the future.
Last edited:
That was the point. To enable true downsizing, variable compression is the necessary technology. Turbocharged engines need to run at competitive compression ratios when off-boost and that will eliminate the biggest obstacle to the full benefit of downsizing. Variable compression turbocharging could be proven uneconomical in the near future, and it's up to Nissan to show the 2.0 VC-T is financially sustainable.
Dynamic Force and turbocharging are not mutually exclusive. Otherwise what do you think the V35A-FTS is?
Mind you hybridization is another way of downsizing. By that definition Toyota is already committed to downsizing. What I was saying was not self-contradictory.
If you doubt the validity of downsizing, read the research papers Levi posted above. They come straight out of Toyota's own research center.
If you insist I post proof of my argument, then I have to say you need to overcome a language barrier first. Most of my (advanced) automotive engineering knowledge come from a group of drivetrain engineers on zhihu.com who are generous enough to show parts of their work that are safe to post to the public domain. Unfortunately for you these sources are in Chinese, and those guys who wrote these posts do not allow repost of these information on a different site.
A particularly interesting person is head of drivetrain calibration at TMEC Suzhou who was in charge of calibration of the 6AR-FSE, 8NR-FTS, A25A-FXS, and A20A-FKS. I will try to get permission from this guy to post translations at a future date so stay tuned.
In this case, I see the deception not in downsizing itself, but in how it was/is promoted by others in the industry (think "Clean Diesel"). While turbocharging and downsizing can be more efficient, it does not mean it is by default. So what they are making -- two decades later -- is closer to their own versions of Toyota 2JZ-GTE, Subaru EJ20TT and Mazda 13B-REW. Those engines were not meant for efficiency, just for power with limited displacement.
Why do I again have the feeling only TMC (and credit to Mazda too) is honestly working on efficient engines while others sell "torque" numbers?
Why do I again have the feeling only TMC (and credit to Mazda too) is honestly working on efficient engines while others sell "torque" numbers?
CIF
Premium Member
- Messages
- 1,675
- Reactions
- 1,825
As you just pointed out yourself, variable compression technology is quite expensive to implement. Furthermore, Toyota has done research on variable compression. Toyota does research on many, many things. If you dig deep and follow the news out of Japan, some concerns still exist about long-term reliability and durability of variable compression engines. I doubt Toyota will be implementing variable compression anytime soon.
Reliability and durability are paramount at Toyota. When you consider the fact that Toyota engineers for a long time have felt hydraulic VVT systems are not reliable enough, that shows you Toyota's dedication to reliability. So unless Toyota comes up with a unique spin on variable compression technology, they are unlikely to implement it anytime soon.
Another somewhat modern example is direct injection. Yes it has benefits, but direct injection also has drawbacks. Normal direct injection systems all eventually lead to clogged fuel systems and significant carbon build up inside the engine which is expensive to clean out. Some automakers have come up with poor workarounds for this. What did Toyota do? They came up with a unique (at the time, and still relatively unique) system more than 10 years ago combining port injection with direct injection. This solved the problems and drawbacks of normal direct injection systems.
Likewise, Toyota has researched HCCI for many years, but I don't see implementation anytime soon as significant hurdles remain. Even Mazda's upcoming SkyActive-X system is only a half-measure or partial implementation of HCCI. It is not a real, full system because even Mazda engineers came to the conclusion that currently too many real world hurdles remain to implement a full HCCI system.
An exception. Again, what do you think the A25A and M20A are? You can continue to ignore the stark evidence I have presented, but it doesn't change the fact that there currently is zero concrete evidence or even indications that Toyota will implement a downsizing strategy in the near future.
Here's another fact; downsizing was debated internally at Toyota over the last few years. Specifically it applies to the XV70 Camry. Implementing a turbo 4 cylinder instead of a V6 as the top engine option was discussed and considered internally, but Toyota decided against downsizing. Toyota looked at owner and customer feedback, and there was a strong dislike against the idea of a downsized turbo 4 cylinder, while at the same time a strong preference for the V6 engine. So Toyota kept the V6 in the Camry. Likewise the new Avalon and ES both keep the V6 as the top engine option.
Calling hybridization downsizing is very debatable, and some mental gymnastics apply here.
Is the new Camry's hybrid system "downsized" compared to the A25A? Of course not, it's an upsize overall. Is the hybrid system "downsized" compared to the V6? Well yes and no. The hybrid system is not meant to compete directly with the V6. So in reality, the hybrid system is a middle powertrain option that's an upsize from the A25A, and a totally different option to the V6.
Or how about we look at the history of the Prius. Over the years and generations Toyota has upsized, not downsized the Prius hybrid system.
Research is just that, research. Toyota researches many, many things that never make it to production.
Just to be perfectly clear, I am approaching this discussion from a global point of view. Toyota is a global company after all. I don't know for sure if you are approaching this discussion strictly from your own local regional perspective, because if you are then it's quite pointless in my opinion.
What some engineers may say or think in the Chinese region does not necessarily apply to Toyota on a global basis. I am looking at all the evidence and documentation from Japan, as it pertains to Toyota on a global basis. Regional differences always exist, but what matters in this discussion is Toyota's ultimate global philosophy.
Here's another stark point. Over the last few years various Toyota executives have actually mentioned that they don't see much point in implementing a full, across-the-board downsizing strategy. A couple of Toyota execs flat out came out and said that Toyota would not be implementing such a thing. Again, engines like the V35A or the (not a Dynamic Force engine) 8AR are exceptions.
Maybe in the far-off future Toyota may actually move to downsizing upon bringing to production unique versions of revolutionary technology like variable compression or HCCI. As it pertains to this discussion though, I talk about the future in terms of the short and mid-term future.
I'll end this post with this thought. Decades ago in the 1960s Wankel engines were talked about as a revolutionary new technology to downsize engines. There was a lot of excitement and discussion when Mazda brought out a production Wankel engine. So after all these decades did the Wankel engine take the auto industry by storm? Definitely not. In reality all the advantages on paper didn't amount to much. In reality significant problems appeared with the engine design in real world usage. Since then, only Mazda remains as the sole company still clinging to Wankel engines. What is my point here? Just because certain ideas or technologies seem revolutionary on paper, does not always mean they end up revolutionary in real world usage.
Last edited:
Ian Schmidt
Moderator
- Messages
- 2,339
- Reactions
- 4,071
Levi: Nissan is going for efficiency also with their VC-T variable compression scheme.
The reason to not downsize yet is that turbocharged engines haven't demonstrated reliability and durability that meets Toyota's standards. So at least you got that part right.
You are getting ridiculous here. Hybridzation is of course about downsizing and there is not even a debate here. Otherwise why do you think the 2.5L THS is called a '300h' system? It is downsized compared to a 3.0L V6 drivetrain, period. Or why do you think the 3.5L THS is called a '450h' system? And Prius, it is a 1.8L system with 2.0L performance so I don't see how it is an upsized drivetrain. The only place where you want to upsize is in a Truck or delivery Van where the engine needs to be overpowered and understressed. Last time I checked the Prius is not know for hauling or towing payload around.
You may have your own opinion but it's not cool to spread obvious misinformation.
Discrediting someone based on their nationality is not a smart idea. This guy reports directly to Aichi. After all the 8AR, 8NR, A25A, and M20A are global engines. Just because the calibration work is done in China does not mean the work is for the Chinese market only. Toyota built a drivetrain development center there because their Japanese facilities were overloaded and understaffed.
CIF
Premium Member
- Messages
- 1,675
- Reactions
- 1,825
Wrong. Toyota isn't going to turbos across the board because that does not fit with the overall Dynamic Force philosophy. Toyota managed to make turbo engines to Toyota standards long ago, dating back to the JZ turbo engines. Turbos prevent Toyota from achieving ideal performance in terms of overall drivability, thermal management, and thermal efficiency with the Dynamic Force engines. The V35A is so far a big exception that came as a result of deeply divisive internal discussions and debates in the company. Electrically controlled turbos in theory might fit Toyota's ideals of Dynamic Force, but there is zero indication Toyota will bring this to production. They've been researching electric turbos for roughly 20 years with nothing to show for it production-wise.
It is clear you have a different interpretation of what downsize means than I do. The 2.5L hybrid system has a 2.5L gas engine *and* electric motors. Logically, factually, objectively HOW is that downsized from a 3.0L V6? If you're only selectively comparing the gas engines, yes its downsized. If you're comparing overall powertrain to powertrain, then the 2.5L hybrid system is about equal overall to a 3.0L V6. You're continually comparing the hybrid systems to larger gas engines, while I am comparing the hybrid systems mostly to their direct non-hybrid gas engine counterparts. It's a matter of perspective.
Let me spell it out for you. The XW10 Prius used a 1.5L hybrid system. The XW20 used an improved 1.5L hybrid system. Starting with the XW30, the Prius used a new 1.8L hybrid system. This has carried onto the current XW50 Prius. Each Prius generation has also received improved batteries, improved electric motors, and more electric power. Also since the current TNGA XW50 Prius is using a non-Dynamic Force 4 cylinder in its hybrid system, then the next-gen Prius is very likely to use a new 2.0L M20A-based hybrid system. This is only logical as the M20A replaces the 2ZR as the main world 4 cylinder engine. There is a CLEAR progression over the Prius generations of gradually increasing displacement, as well as increasing electric power/capacity. By the very definition of the word, this shows upsizing has occurred during the history of the Prius. This is irrefutable, so I don't know your issue here.
This has nothing to do with nationality, relax. This has everything to do with the concept of regional differences in general. Do specific regional European markets, African markets, South American markets dictate the overall global Toyota strategy? Of course not. The overall global Toyota strategy is formulated taking into account the needs of all the regions. Some differences are allowed and allotted to specific regions. Toyota globally strives to build cars that drive well in any region, in any market, under any conditions. Even here in North America, the regional engineers do not get final say. Final say obviously happens at Toyota global headquarters in Japan. Under Akio Toyoda though, individual regions have received more say and more autonomy in terms of how they fit into the global Toyota strategy. By the way, Toyota opened a new large global powertrain building right near their global headquarters in Japan a few years ago. Main global powertrain development happens in that new building.
I have no interest in taking this discussion further at this point. I have said what I felt was needed to be said. If you have any direct proof or indication of Toyota moving to downsized engines, post it. Otherwise nothing more of note can be discussed here. Subjective interpretations of what downsizing means is not a meaningful discussion.
Last edited:
