Why no direct injection?

The generation of Prius was introduced the Spring of 2009.

That means the next is expected just 2 years from now.

Toyota has already stated increasing engine efficiency is a big priority for it.

 

From the GS450H spec page, "

direct and port fuel injection" S​

o, it might be like Subaru's newer FA boxer engines, found on the BRZ/FR-s. At certain RPMs is uses multiport fuel injection and at other RPMS it uses Direct Injection. At low RPMs and high RPMS it uses both injectors simulataneously, but at mid RPMS it just uses Direct Injection.

Who knows if the GS450H does it the same way. If it were pure DI I wonder if there would be more MPG. I'm thinking it will be a minor bump in MPG when Toyota renews the Prius with DI. HCCI engines will be what can bring it up significantly, IMO.

 

Yes the Subaru engine uses the lexus port plus DI system. There are a whole raft of changes including DI that toyota is using in the lab to raise efficiency of their normally asparated engines from 38% today to 42% in the future. The only reason a more efficient DI engine would not make the next prius is to keep cost down.

HCCI is one of those technology that just is not ready yet for production vehicles. It does not work well at high loads, and there are issues switching from HCCI to stoich combustion.

The issue toyota mentioned with atkinson and DI, is related to timing. With late intake valve closing the injector need to not put a cooling charge out until the valves are closed. This means they need to mix the fuel in a shorter period of time. Mazda seems to be able to handle this fine with their multi mode skyactiv engine with expansion of 14:1. I can't believe Toyota is having technical issues, but they may be having trouble getting around patents I would bet that any challenges will be gone before the next generation of prius comes out.

 

Maybe not the average Prius driver, but a lot of them do. Don't need 200 HP, 150 will help if they don't add weight.

 

I'd like to see a 300 hp 400 foot pounds of torque Prius model

I'd be first in line trading mine in for that baby

Mike

 

Skip hybrid, just get Model S P85.

 

I doubt you'll see turbo/super charging on a Prius anytime soon, but I think DI is a real possibility on the next gen. Make the ICE a little stronger, make the battery/motor more powerful, about 150-160 total hp would be sweet, and oh yeah 70 mpg!

 

Interesting to note the 2013 Accord 4 cylinder sedan and coupe engines are direct injected, but the 1.8L Civic gas is not, still multi-port. Honda does not list FI spec on site for the Plug-in Accord, but I'll bet it's DI.

 

What's the advantage of 3 cylinders over 4? Is the advantage from the displacement difference or is there something else that makes 3 cylinders more efficient than 4?

 

A 3 cylinder motor can still be built for Mad Powa. Need boost to get the torque or use lots of electric motor assist.

Mike

 

The higher the volume each cylinder has, the lower the losses (not only friction but heat also)...

 

Toyota's cheap...what else is new? have you actually looked around your car in and out?

 

//quote//I would think the Prius would benefit mpg wise by having higher electric torque and allowing that torque at higher rpm's than it is allowed now. Something like a Prius HO with a posi that has 300 foot pounds of torque from zero mph to the limiter. That car would fly yet could get high mpg numbers because of the increased use of the electric motor. It would require a higher capacity battery bank to supply the increased current to the electric motor. Imagine a 13 something second quarter mile time in a Prius yet still gets 50+ mpg when driven normal That car would sell. Make that an option for those that like a quick car yet being a Prius and saving gas.

Mike//quote//

I thought the prius would lose efficiency by running the electric motors more? The reason is from the conversion of fuel to mechanical motion to electricity then back to mechanical motion. I believe this is why Toyota connects the drivetrain directly to the engine, unlike the volt which acts more like a locomotive.

Mike, I do like your thoughts on making the prius faster. It sure would make all those haters envious, and maybe even understanding of such a fine automobile. The prius will burn rubber from a stop. My car will not. I think it has plenty of power already, but for some odd reason a lot of people imagine it as slow. Too bad A123 batteries are now china owned, they would make a fine replacement for the NIMH pack.

​

 

Those A123 cells would be nice to have. I wish I had the funds to try fitting a Camry Hybrid motor/HSD in my car just to see the performance gain of having 200hp and whatever torque that larger system provides. That'd be fun

Mike

 

Panasonic now makes fine lithium batteries, they are in the toyota alpha (japanese and european version of the prius v) as well as the ford fusion and c-max hybrids. Toyota could, but rumors are they won't, drop a lithium battery in the prius. If it was the ford size (35kw) it would likely fit exactly where the nimh one does but provide 11 more hp, but the hsd would need to be reworked to use the power. Make the engine bay a little larger, and maybe you could drop the di version of the camry hybrid, as used in the not sold in america Lexus ISh. That would raise horsepower to 223 on premium gas (you should be able to use regular with slightly decreased hp and efficiency). The ice's peak efficiency is the same as the one in the prius. this configuration would add weight, and you would want to upgrade the suspension for the greater hp and weight. Still highway mpg might even be better with this car than the prius if you are going the same speed. City mileage will be reduced, unless you pulse and glide. 0-60 when pushed would be around 6.5 seconds and still be efficient.

 

Also Tesla uses Panasonic cells, AG.

 

Yes they do, but they are like the consumer cells so they need more expensive electronics to have them behave well. This is great for big packs of a plug-in, but not so great for small packs in a hybrid.

 

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