viable way to make AC more friendly...

[Matt Timion]

Just thinking out loud.

Assume we hook up a small electric motor to the AC pump that only turns the compressor when the AC button is pressed.

Another option is to do the same with the power steering, but it will be activated using a TPS sensor somewhere inthe steering column/hubs/etc. A small computer will activate the electric motor to turn the PS pump as soon as you actually need it. The rest of the time it will be turned off.

How powerful of an electric motor would you need to turn the AC compressor and PS pump?

[diamondlarry]

I've heard A/C takes 10-15 hp. I wonder if there is a way to see what Toyota uses with the Prius?

[Matt Timion]

Originally Posted by diamondlarry

I've heard A/C takes 10-15 hp. I wonder if there is a way to see what Toyota uses with the Prius?

I'm unsure if it takes that much honestly. My exact car without AC wouldn't be expected to have a 10HP boost over my car.

Sigh, if only there were a junk prius or insight in the junkyard.

[Silveredwings]

My understanding of the Prius AC compressor is that it has an electric motor in it (hence a hybrid in itself) that can run the compressor when the ICE is shutdown (clutch disengaged of course). The reason they still drive the compressor with the ICE at all is probably that it's more efficient to use surplus ICE horsepower than exclusively electric.

So redesigning your car to use an electric motor for AC would elliminate the belt friction? Is that the idea?

As for the PS, I've been thinking the electric power steering (EPS) setup from an Ion, or S2000 would be the way to go. Simpler, lighter, and draws power only when needed unlike the hydraulic which would need an electric motor running constantly if not run off the belt.

[JanGeo]

http://www.ecycle.com/Solutions/Compressor%20Drives.htm

Here you go!

Oh and the Mini Cooper apparently uses an electric motor powered power steering.

[Matt Timion]

Originally Posted by Silveredwings

So redesigning your car to use an electric motor for AC would elliminate the belt friction? Is that the idea?

Belt friction and pumping losses. Removing these accessories is IMHO going to help a lot with FE.

Of course there is still the issue of the alternator powering these accessories, which is powered by the ICE. Removing these items will require the existance of an alternate means of power, such as a waste exhaust alternator setup.

[JanGeo]

Originally Posted by Matt Timion

Removing these items will require the existance of an alternate means of power, such as a waste exhaust alternator setup.

NO NO NO a bigger battery and Solar Cells on the roof! You want to add energy to the "system" as cheeply as possible all the time.

[Silveredwings]

Originally Posted by JanGeo

Oh and the Mini Cooper apparently uses an electric motor powered power steering.

Cool. I didn't know that.

[Silveredwings]

Originally Posted by Matt Timion

Belt friction and pumping losses. Removing these accessories is IMHO going to help a lot with FE.

Of course there is still the issue of the alternator powering these accessories, which is powered by the ICE. Removing these items will require the existance of an alternate means of power, such as a waste exhaust alternator setup.

Won't you still have to pay for the pumping losses in some form or another? Maybe with an electric water pump (different thread http://www.gassavers.org/showthread.php?t=1265), you can save energy by cycling the pump when it's not needed instead of the 100 year-old technology of short-circuiting the pump with the wax thermostat. Although the circulating coolant does serve a function of reducing hot spots in the head.

Doesn't the waste exhaust cost the ICE something in losses from a change in back pressure? Just curious.

[JanGeo]

Yeah messing with the exhost is not a good idea - using the heat is ok as that can cool the gasses and reduce volume and pressure but water pump and steering pump pumping losses at higher RPM will be where the big savings will be. I remember when I took the fan blade off the water pump in my Rambler how the mpg went up and the engine ran a lot quieter PLUS no missing fingers from the Metal Fan Blade. Go with a variable speed pump motor for the water pump as you will want to cool the engine more when it overheats.

The Mini Cooper makes some weird whining noises when the power steering pump is running as you turn the wheel.