How to build a muscle car for better fuel economy?

[freebeard]

TESLA, eat your heart out!

Tesla won't notice, they're going for orbit around Mars.

I am just saying, I refuse to reconfigure my motor set-up if the hub motors are going to be this much of a royal pain to figure out...

Well, if I can't use the electric assist all the time then I suppose I can't use it period as there is no benefit to having it if the system can't be designed for self-sufficiency.

Well, if two hub generators on the rear of the car are not enough for this set-up, how about also including the altermotor?

If the system won't be AWD and self-sufficient then I see no point in having it.

I'm starting to admire the persistence of the other posters. I think you're trolling. I shall lurk more until I see some indication you have read and understand:

https://en.wikipedia.org/wiki/Kineti...ecovery_system

We haven't talked about any of the other ways you could get what you want:

• Parking in a solar carport with an automatic tentacle to recharge.
• Having the V-8 run 24/7 to recharge a massive battery.
• Having two switchable battery banks so one can charge while t'other discharges.

[Ecky]

Originally Posted by Phoenix'97

I hope I am making myself clear...

In a nutshell, can I produce enough energy to offset what the two front steering wheel hub motors only are consuming? This is why I suggested using another pair on the rear drive axle as purely generators for the front hub motors that will be pulling the car while the gasoline engine is pushing the car with it's combined torque. IF this set-up were not producing enough power, I would have to resort to using an altermotor attached to my LT1 V8.

Am I still missing the point behind your comments?

I suppose I would have to settle with the electric hub motors kicking in for stop-and-go driving, my spirited "launches", and even for conditions on the highway when I don't have enough torque up a mild grade when cruising at 1500 RPM, but I don't see why I can't have the electric assist on all the time...

With an alternator an solar panels, you cannot produce enough energy to power the front hubs. Your alternator would cause a tremendous fuel economy hit even if you could, so this would be a Very Bad Idea in terms of economy.

You can if you add an altermotor and basically only use it to suck power from the engine, but doing this will result in worse gas mileage too. You'd basically be taking energy from the rear wheels and sending it to the front at a 20% loss. Since it takes a fixed amount of power to cruise down the road, that loss comes straight from your gas tank.

Which is not to say you can't still have hub motors in both front and rear, you just don't want to use them all the time! The most efficient way to use them, the one that gives both power and economy, is to use them to accelerate, use them to capture energy when you slow down, and let the gas engine do the work when you're traveling at constant speed.

[Ecky]

This video is very simplistic, but might be informative to you:

https://www.youtube.com/watch?v=Rn1VQJkZSvE

I'll see if I can dig up anything better. But basically, in summary you don't ever want to be electric braking the rear wheels to give power to the front (or vice versa).

[Phoenix'97]

Originally Posted by freebeard

I think you're trolling.

Why do I keep getting called a troll? For being stubborn? For trying to learn what options I have pertaining to the subject being discussed? Or is it that I have such a strong conviction to find a way to use electric assist full time for driving?

Originally Posted by freebeard

We haven't talked about any of the other ways you could get what you want:

• Parking in a solar carport with an automatic tentacle to recharge.
• Having the V-8 run 24/7 to recharge a massive battery.
• Having two switchable battery banks so one can charge while t'other discharges.

For something that wasn't meant to be a massive and expensive project, I am ever fearful of the additional mods being proposed.

[Ecky]

It really is a lot to wrap your head around, I understand. Even after owning a hybrid for years, I still occasionally have a moment where the reason they've done something one way dawns on me.

[Phoenix'97]

Originally Posted by Ecky

It really is a lot to wrap your head around, I understand. Even after owning a hybrid for years, I still occasionally have a moment where the reason they've done something one way dawns on me.

I guess what keeps on nagging me is:

1. How much power is being drawn under light load by the both front hub motors.
   
2. How much power is being created under light load by both rear hub generators.
   
3. How much less work is the gasoline engine making the front hub motors work?

I have power generation every time the car slows down or stops. I have the front hub motors performing some work but not all the work and hence they shouldn't be drawing much power for the their torque output at that time.

The gasoline engine is pushing, the hub motors are pulling, total work load is divided, and rear hub generators are recharging the system batteries.

If I am annoying you with my ignorance you don't need to comment further...

[Ecky]

I'm not annoyed in the least.

I'll try my best to explain:

Unless you plug your car in, the source of all energy in your car is ultimately from gasoline. Sometimes you can scavenge some of it back by capturing it when you slow down, and this is one way hybrids save fuel.

Let's say you want to run the front hub motors all the time to produce power, and you want to create that power from motors attached to the rear wheels (either hubs or altermotor). If you want to send 5HP to the front motors, you'll have to take away ~6HP from the rear. Since all power ultimately comes from gasoline, your gas engine actually has to work harder, burning more fuel.

Or in other words, let's say you need 20HP to overcome air resistance and move down the highway. With the gas engine alone, you would burn enough fuel to make 20HP and cruise along. If you want instead to send 5HP to the front wheels for full-time AWD, you would have to burn 21HP worth of fuel, because although the front is now subtracting 5HP from what the gas motor has to make, the rear is adding 6HP, and that extra has to come from gasoline.

Normally hybrids try to only use the energy they can capture for free. For instance, when you go down a hill, it saves all of that energy up to be used to go up the next one. Without the hybrid system, you'd lose that energy to your brakes, and would have to burn more gasoline to get up the other side. The same applies to stopping at a traffic light; when you slow down, it saves up your momentum in the battery, and then uses it to get you going again, so the gas engine doesn't have to. You also get the added benefit of a ton of extra torque when accelerating, making your car faster off the line with no downside.

Running the motors all the time requires a constant source of electricity, and when you try to make that with a generator, you lose. You really want to use as much "free" energy as possible.

[Phoenix'97]

And the power output of the gasoline engine plays no role in this equation? Lets say that this engine has no issue producing lots of low end torque, so even with the taxation from the rear mounted hub generators, it would still be able to produce the same power on the same gallon or spritz of gasoline per cycle per cylinder.

This is why it is nagging me!

[Ecky]

If your motor can produce more torque, it's simply capable of burning more fuel at that RPM. More fuel per mile = less miles per gallon. Torque ultimately comes from gasoline.

EDIT: That's not to say there aren't some things you can do which will improve how much usable energy you can get out of gasoline... but for the most part, it's true.

[Ecky]

So, because of this, most of the ways to save fuel that we work on here are those that try to reduce loss. Anti-friction coatings for instance DO work but putting a sheet of plastic under your car will probably have a larger impact on the highway, and slowing down 5mph will have an even larger impact. Taking weight out of your car can save you a few percent in city driving, but turning off your engine at stoplights will save you more and becoming more conscious about the flow of traffic and conserving momentum (essentially preventing having to slow and accelerate the entire mass of your car) saves the most.

That's not to say economy engine builds aren't done, but it doesn't make a lot of sense from an economic perspective to spend $xxxx on exotic coatings when $xx in corrugated plastic will actually help your gas mileage more, and driving modifications are free and will have the biggest impact.