New Hybrid Technologies Boost Efficiency

I think the next area of advancement is addressing the warm-up cycle. The exhaust heating loop helps but the recent report of -40C driving suggests more can be done.

Perhaps conformal, engine block insulation and rely upon coolant loops and radiators to handle high heat days.

Bob Wilson

 

There's an easy one - active grilles which open/close based on the amount of cooling needed.

I'm guessing that we haven't seen this yet because it would significantly increase the cost to repair a lot of front-end collisions.

 

Bob, I think you just turned on the golden light bulb! Coolant loops! Perhaps an electrically-controlled valve and hose that bypasses the radiator and sends the coolant right back to the engine is the golden solution! Depending on temp, throughout the entire drive, the computer can turn the valve and direct coolant either into the radiator or right back to the engine!

(Drees, on the other thread I had originally suggested the same thing - louvers like they had in the 1910s to 1940s - but I think Bob Wilson's idea is the clear winner)

Aside from warm-up (hey, I live in Southern California), significantly increasing the capacity of regenerative breaking seems to be the obvious next-step. Which leads me to wonder why Toyota didn't already factor that into the GenIII Prius. Any ideas why?

 

Not sure if you're being sarcastic or not, but engines have had mechanical thermostats to control coolant flow for ages. And the Prius now has an electrical coolant pump which should give ultimate control over engine cooling.

Ideally, mechanical brakes would only be used to keep the vehicle stopped (or nearly stopped).

The biggest limitation in current hybrids regarding regenerative braking capacity is battery limitations. You can only charge the battery so fast before it starts having a detrimental affect on battery life.

Either a larger battery or a battery chemistry which can handle those types of loads better would be required. Obviously, a larger battery would also then have the ability to store more energy for those long downhill runs, too, but the opportunity for most to use extra capacity is limited most of the time.

A factory built PHEV should be able to capture significantly more energy during braking since it's electrical bits should be beefed up a decent amount over a normal hybrid.

 

What purpose could blocking the radiator have when the thermostat won't open until the engine block coolant has reach operating temperature?

 

The surface of the engine and transaxle lose a great deal of heat. This evident when watching the coolant temperature after the car is turned off. What I'm suggesting and has already been tried is a thermal blanket around the engine and transaxle. Alternatively, make the engine compartment an insulated, thermal chamber with effective air vents. This is what we attempt with our radiator blocks.

There have been several design efforts in the Prius:

• NHW20 - thermos, to hold hot coolant to warm up the engine and more relaxed engine warm-up control laws.
• ZVW30 - exhaust heat recovery to warm up the engine and further relaxing of engine warm-up control laws.

IMHO, a thermal blanket makes a lot of sense as well as making the engine compartment air-tight in cold weather.

Bob Wilson

 

Actually, and I'm somewhat embarrassed to say this, I didn't know about mechanical thermostats. I remember always hearing my dad at car shows and when I was at the mechanic (back when I had my first car) talking about "the mechanical thermostat opens when the engine is up to temp," but I guess I never really understood exactly what that meant. Thank you.
Your explanation about maximum charging rate of a battery makes sense. Good explanation. I wonder if there is a mediating technology (like a capacitor, for example) that could buffer the recharging by accepting a huge amount of energy and then slowly releasing it to the battery. A flywheel could work, but I'm sure there are better ways.

(Edit: Maybe a transformer could help. current-->Voltage )

Thanks! Bob, I'm learning a lot from this thread. thanks!

 

No worries. The cooling system is sized for worst possible conditions - if it ran coolant through it at full flow all the time, the engine would never warm up most of the time.

Yes, ultra-caps are one way people have proposed to buffer the power in/out of a battery, but the technology just isn't there yet. I suspect that by the time it is, batteries will be good/cheap enough that it won't make too much of a difference except for specialized applications.

 

Are you looking for following kind of thermal blanket?
http://priuschat.com/forums/gen-iii...estion-leaving-car-overnight.html#post1017169

Ken@Japan

 

Any chance someone makes a fireproof insulation that you can stuff in there for those really cold days?