Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - Why do a grill block when you could put excess air to good use?

ChazInMT · 09-20-2011, 04:30 PM

ConnClark putting something in an airstream will be a less efficient way to do something. Period. You even admit it when you say "No" to "will you get something for nothing."

And, where do you get the idea that a turbine in the grill is a block? It is a huge flow restriction. The air comes in, gets massively slowed down due to having given up its energy to the turbine blades, and exits the back. A turbine is like a Cd 1.5 element on the car. The air does not see the turbine and decide, "Hey, maybe I'll just go over the hood instead", it eats all the air that hits it. A grill block makes the air go over the .32 Cd part of the car instead of through the 1.1 Cd part in the engine bay. Does this basic concept make sense to you? The Turbine is NOT a block. It would be a huge drag for its size no matter where you put it. Something that forces air up and over the roof of a car (solid grill block) is not a drag, it helps eliminate drag.

Lets review, Turbine in slipstream: Adds Drag. Something that diverts air from a high drag area to a low drag area: Reduces Drag.

Now, I'm sorry that the "Rant" portion of my dialog contained too much technical information for you to understand, power generation efficiencies and all, but the facts included in my “Rant” say why your idea, while creative, is doomed by science to never work. Same reason why you can't just grab your own feet and pick yourself up of the ground, it's all there in the "Rant".

If you want to come up with efficiency numbers and show how I'm somehow mistaken in my reasoning, feel free to do so. But please for the sake of not looking like you really have no concept of the basics, include some numbers and diagrams with your idea, not just a bunch of “I swear I think it works” statements, cause heretofore, that’s really all you’ve given.

Now the NASA Link
Capturing energy from a vortex forming element on an airplane, such as the NASA thing, is entirely different than what you are proposing. NASA doesn’t want to put a generator in the inlet of an engine, or anywhere else for that matter in the slipstream. They want it in a very specific place to try and capture the energy used in vortex formation and put that to use.

Now, if you want to propose putting some sort of generation device behind the C-pillar on a car to capture the same energy that goes to waste generating vortices there, that is a different story, by eliminating a vortex, you will gain a potential amount of improvement in the Cd of the car which could be used to make electricity. I'd say that‘s a good idea. But, good luck engineering it. That’s a completely different proposal then putting a high drag element on a car in front of a medium drag element and hoping to save gas.

You do want to save gas right??? I mean, again, I’m not saying you won’t generate electricity and use it somehow with your proposed device. I’m just saying you’d get like 33 mpg with it, and 35 mpg without it YMMVBISAHWI. (Your mileage may vary but it sure as heck won't improve)

09-20-2011, 04:30 PM	#31 (permalink)
ChazInMT Aero Deshi Join Date: Jan 2010 Location: Vero Beach, FL Posts: 1,065 MagMetalCivic - '04 Honda Civic Sedan EX Last 3: 34.25 mpg (US) Thanks: 430 Thanked 669 Times in 358 Posts	ConnClark putting something in an airstream will be a less efficient way to do something. Period. You even admit it when you say "No" to "will you get something for nothing." And, where do you get the idea that a turbine in the grill is a block? It is a huge flow restriction. The air comes in, gets massively slowed down due to having given up its energy to the turbine blades, and exits the back. A turbine is like a Cd 1.5 element on the car. The air does not see the turbine and decide, "Hey, maybe I'll just go over the hood instead", it eats all the air that hits it. A grill block makes the air go over the .32 Cd part of the car instead of through the 1.1 Cd part in the engine bay. Does this basic concept make sense to you? The Turbine is NOT a block. It would be a huge drag for its size no matter where you put it. Something that forces air up and over the roof of a car (solid grill block) is not a drag, it helps eliminate drag. Lets review, Turbine in slipstream: Adds Drag. Something that diverts air from a high drag area to a low drag area: Reduces Drag. Now, I'm sorry that the "Rant" portion of my dialog contained too much technical information for you to understand, power generation efficiencies and all, but the facts included in my “Rant” say why your idea, while creative, is doomed by science to never work. Same reason why you can't just grab your own feet and pick yourself up of the ground, it's all there in the "Rant". If you want to come up with efficiency numbers and show how I'm somehow mistaken in my reasoning, feel free to do so. But please for the sake of not looking like you really have no concept of the basics, include some numbers and diagrams with your idea, not just a bunch of “I swear I think it works” statements, cause heretofore, that’s really all you’ve given. Now the NASA Link Capturing energy from a vortex forming element on an airplane, such as the NASA thing, is entirely different than what you are proposing. NASA doesn’t want to put a generator in the inlet of an engine, or anywhere else for that matter in the slipstream. They want it in a very specific place to try and capture the energy used in vortex formation and put that to use. Now, if you want to propose putting some sort of generation device behind the C-pillar on a car to capture the same energy that goes to waste generating vortices there, that is a different story, by eliminating a vortex, you will gain a potential amount of improvement in the Cd of the car which could be used to make electricity. I'd say that‘s a good idea. But, good luck engineering it. That’s a completely different proposal then putting a high drag element on a car in front of a medium drag element and hoping to save gas. You do want to save gas right??? I mean, again, I’m not saying you won’t generate electricity and use it somehow with your proposed device. I’m just saying you’d get like 33 mpg with it, and 35 mpg without it YMMVBISAHWI. (Your mileage may vary but it sure as heck won't improve)