No more Prius Prime.

So, despite the added weight of the battery, Prius Prime gets a higher HV mpg than the non-plug-in Prius then. This agrees with the EPA mpg values.

 

Then the Ioniq had greater thermal efficiency than the Prius of the time.

Mmm, Hyundai uses dual fuel injection for the port/direct injection system. Then they go and have a dual port system that has two injectors through the ports.
Smartstream – Hyundai Motor Group TECH
Dual fuel injection seems to be the accepted generic term.
https://engineerine.com/port-vs-direct-vs-dual-injection/

Was Toyota the first to develop duel fuel injection? I know they had an earlier generation in some Lexus models, but no luck finding who invented it.

TIL direct injection predates port. First use was in 1925. Mitsubishi made the first electronic system in 1996.

When I have asked people that have hypermiled both a gen2 Prius and a later model which was easier to glide, the response is nearly always the gen2. My results with the Prius were because I could glide for much of my commute. An engine that burns no fuel over a mile is doing best.

New, the newer Prii are more fuel efficiency overall, and the typical driver has an easier time getting that better rating. I just don't think I'd be beating the current Prius EPA by the same rate as I did in the 2005. Based of the gen2 results, I should get 68 mpg in a gen4. I should be getting closer to 38 mpg with the Outback.

Now, does anyone (@Salamander_King ?) know if the larger battery in Prius Prime allows more regenerative braking than in non-plug-in Prius? You would think it would. That would increase the HV mpg quite a bit.[/QUOTE]It does.

https://www.cleanmpg.com//community/index.php?threads/49683/page-13#post-423256

It isn't just more regen that improves the fuel efficiency. The about are from steady speeds with cruise control. The larger battery also lets the engine run near peak efficiency for longer periods when that output is more than needed, and longer engine off periods.

 

You are confusing dual injection with dual port injection. Dual injection combines direct injection with port injection. There is no direct injection in dual port injection.

Ioniq does not have direct injection, dual injection, or dual port injection.

Thermal efficiency has a lot of factors. Direct injection only helps.

Yes, you could easily get 68 mpg (73 mpg on the multifunction display) on Gen-4 Prius Prime without hypermiling. With hypermiling, you could get 90 mpg and more.

 

Yes, I caught the mistake.

The Ioniq has a GDI engine; I think all their current hybrids are. My remarks about dual port and dual injection where in reference to the new 2023 Niro. It is using an engine from the Smart Stream family. Depending on application, they have multi(dual) port, direct, or dual injection. Though, the Niro will likely end up with direct.

I only remarked on the dual injection, because I thought Toyota was the only one using it. Turns out Hyundai has been doing so for nearly as long. Most of the reports when the engine was new were focused on the continously variable valve duration(CVVD).

 

Yes, they both have a 13:1 compression ratio and 40% thermal efficiency.

The new Toyota inline 4-cylinder 1.8-L ESTEC 2ZR-FXE gasoline engine for hybrid car

Development of new high-efficiency Kappa 1.6-L GDI engine

Reportedly, the Gen 5 Prius/Prius Prime will use the five-year-old dual-injection (GDI and port; "D4-S") Corolla M20A-FXS engine with a 14:1 compression ration and 41% thermal efficiency. If that is really the case, I am surprised that they haven't developed a new engine for the Gen 5 Prius/Prius Prime.

2.0-liter dynamic force engine, a new 2.0-liter direct-injection, inline 4-cylinder gasoline engine | Toyota's new powertrain | TNGA | Mobility | Toyota Motor Corporation Official Global Website

Mazda Skyactive-X with a 16.3:1 compression ratio is claimed to have 43% thermal efficiency.

https://min.news/en/auto/bcd60a469bb229313406c71f6f6d8653.html

 

That's Toyota. Why spend money for new while the older can still be sold.

With hybrids being available for nearly every model, the Prius is no longer a halo car for efficiency or technology.

It almost runs like a diesel. Toyota's latest diesel is 44%, IIRC. The SkyActiv-X was deemed too expensive for the US market when it came out in the Mazda3. Perhaps the calculation balance has changed.

 

The SkyActiv G required premium fuel, but Mazda lower its compression ration for the North American market.

The goal of this technology development is to get a gas engine running on compression ignition like a diesel. High octane works against that.

"Mazda would’ve wished to run 80-octane gasoline in the SkyActiv-X rather than 87 to 90 because higher octane makes combustion more difficult. In order to prevent knocking, the spark plugs control exactly when to ignite the air-fuel mixture in the combustion chambers at a compression ratio of 16:1." - https://www.autoevolution.com/news/mazda-selling-skyactiv-x-engines-like-hotcakes-in-europe-139399.html

"“We found that 91RON fuel gives better low end torque, and higher RON means it’s harder for compression ignition to occur,” says Mr Hiroshi Tokushige, Mazda’s deputy general manager of powertrain development." - 5 Things You Should Know About Skyactiv X - Online Car Marketplace for Used & New Cars

The X uses compression ignition at lower loads, and spark at high. Valve timing lets it lower the effective compression ratio when using spark.

 

Our 2nd gen Honda Civic Hybrid employed a couple of items I've not heard much of since:

Dual spark plugs (2 per cylinder, with staggered ignition)

Low and high height cam lobes (lower lobes for everyday, higher for hard acceleration. Hydraulics could switch between the two)

 

May not be common, but isn't rare. Planes have it for redundancy. Cars for emissions and efficiency. There is a lot of things that need to go at the top of a cylinder though.

That's variable valve timing. Lots of systems around now. The new Prius uses electronic controls instead of hydraulics on the intake side.

 

Variable valve timing and having two lobes with different lift amounts are different? Our Civic had the latter; you could feel it kick in, say accelerating on an up-incline.

 

What??

Prius has always been the pinnacle of hybrid and plug-in hybrid electric vehicles, and it will remain that way until the phaseout of the internal combustion engine. Ioniq (dual-clutch transmission ) and others are far behind in quality and performance. You can drive one of those cars instead if you are not into quality and performance but value. If you also factor in reliability, you shouldn't even consider Ioniq etc.

Gen 5 Prius/Prius Prime is a substantial improvement over Gen 4. It will make most other cars look outdated and primitive.

It will already have an engine with a 14:1 compression ratio, which is only second to that of Skyactive-X. I don't want an engine with a 16:1 compression ratio if it won't have Toyota's unsurpassed reliability.

 

Why are you still trying to save more money? Life is too short. With a single car, you will be imprisoned to home when your wife is working. Trade in the Pathfinder for a 2023 Prius Prime SE and call it a day.

 

Oh, timing and lift are different. Both involving the manipulation of the valves' operation means it is rare to not have variable lift with the timing; your Civic had both. The variable timing was in use decades before the first variable lift patents; Porsche, Fiat, and GM through 1959 to 1975. Honda may have been the first to have lift in a non-exotic car, but Toyota and Nissan soon followed.
https://en.wikipedia.org/wiki/Variable_valve_timing
https://en.wikipedia.org/wiki/Variable_valve_lift

I think articles written today assume variable timing systems include lift. Maybe economy versions of engines exclude the lift. Which would be why you don't hear much about lift beyond it just being old technology. I remember talk of Fiat having throttleless engines when they came back to the US. Lift wasn't mentioned, and it is continous variable valve lift that would make that possible. The new things with valve control are camless systems to open and close them, and variable valve duration.

I was only talking about Toyota, since the question was about their decision to use already released engines in the new Prius. The Prius was their halo car, to their company, for emissions and efficiency. That role has been shifted to the Mirai, and now the bZ's. Toyota is acknowledging the Prius' importance in the progress in lowering emissions with the Beyond Zero badge, but it is no longer their flagship for that.

From the info that has been released about the new Prius, there is no new technology in it for improving emissions or efficiency. The engines and drive train components are all already available in different car models. The only advantage it seems to have over a Corolla hybrid for efficiency is in aerodynamics and maybe the larger wheels. Having a PHEV option isn't new, and Toyota has already expanded that to the Rav4.

If Toyota's goal for the Prius was still leading emissions and efficiency, they wouldn't install the 2L and talk about the power gains. I think the efficiency gains are impressive in that light, but Toyota might have gotten 60mpg if that was still the main focus.

The Prius is still popular in Japan, like the Aqua. Which is why it hasn't been cancelled. The Prius is on the larger size for that market, and is against the Corolla, which is why Toyota is focusing more on performance and making in more upscale. An article or post called it getting the Crown treatment. Where it makes financial sense, they'll sell it elsewhere. That consideration is why Europe is only getting the PHV.

When SkyActiv first came out, it had 14:1 compression. It was also an Otto compression ratio, not 14:1 in only the power and exhaust stroke like an Atkinson. For North America, it was detuned to 13:1 because of our lower octane regular gas.

Is the mpg estimate there for the Prius Prime and Pathfinder near what you actually get. Much of what people think of as city miles these days are closer to the highway test conditions than city. While the official combined mpg is 55% city to 45% highway, the EPA uses a ratio closer to 40:60 for their GREET model, as that is more in line with most Americans routes.

I've heard of people using their car's reported average speed to determine their city:highway ratio. The city test average is 21.2mph, and highway 48.3mph.