Go Back   EcoModder Forum > EcoModding > Hybrids
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 06-22-2010, 05:03 PM   #1 (permalink)
Basjoos Wannabe
 
ShadeTreeMech's Avatar
 
Join Date: Apr 2009
Location: Arkansas
Posts: 870

The Van - '97 Mercury Villager gs
90 day: 19.8 mpg (US)

Lyle the Kindly Viking - '99 Volvo V70
90 day: 25.82 mpg (US)
Thanks: 174
Thanked 49 Times in 32 Posts
Are we thinking about the hybrid the wrong way?

Best I understand it a hybrid has 2 power sources. Sadly though battery technology is way behind what our needs are.

While driving my max, I noticed the scan guage tells me only 50 hp (or less) is required to keep the vehicle moving. I've also learned that pumping losses are one of the biggest fuel economy disadvantages of the throttle body equipped gas engine.

If a sedan were equipped with a rear axle from a truck with a motorcycle engine attached to the rear axle, and the front wheel drive car remained intact otherwise, wouldn't better economy be acheived by using the underpowered motorcycle engine for cruising? This is also assuming a fuel injected motorcycle engine, which would be slightly more efficient, and a water cooled one would be more ideal. Have the fuel from the car's OEM tank routed to the motorcycle engine as well as the OEM engine. The MC engine would likely have to be run at WOT or nearly so to produce the necessay power, but that is more efficient anyway. The advantage vs a battery powered setup would be less weight, and likely less room required (I had initially thought of a similar arrangement, substituting the MC engine with an electric motor and battery pack)

Is there any merit to this idea, or will it simply be buried into the pages of my many unfounded ideas based on incomplete data?

__________________
RIP Maxima 1997-2012


Quote:
Originally Posted by jamesqf View Post
I think you missed the point I was trying to make, which is that it's not rational to do either speed or fuel economy mods for economic reasons. You do it as a form of recreation, for the fun and for the challenge.
  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 06-22-2010, 05:13 PM   #2 (permalink)
Master EcoModder
 
Patrick's Avatar
 
Join Date: Apr 2008
Location: Northern Florida, USA
Posts: 510

Hot Tamale - '10 Toyota Prius III
Thanks: 27
Thanked 96 Times in 70 Posts
The 2010 Prius weighs about 165 pounds more than the 2010 Corolla. Can you build your hybrid with less than 165 pounds added?

Also, the space taken up by the battery is not noticeable (it's behind the back seat and under the rear cargo floor), and the electric motor is integrated with the "gearbox" under the hood. I don't know if a motorcycle engine driving the rear axle could be made to take up less room.

The Prius computer tries to run the engine in an area where its BSFC is lowest, and by driving it a certain way you can help to keep it there. So I'm not sure that throttle body pumping losses are as big of an issue as with normal ICE cars.
  Reply With Quote
Old 06-22-2010, 05:30 PM   #3 (permalink)
Master EcoModder
 
Join Date: Sep 2009
Posts: 5,927
Thanks: 877
Thanked 2,018 Times in 1,302 Posts
Been working on this for years. Study the BSFC charts of many engines and you will notice a pattern and a fairly consistent BSFC amount for many different engines, with the largest difference between gas and diesel.

On those engines that are configured for economy, you will find that most of the performance improvements applied recently are relatively insignificant, beyond fuel delivery systems.

By this I mean at peak BSFC even a 2 valve 3.8 liter push rod Buick V6 dating back to the 60s can still compete if it has the latest fuel injection technology.

Gearing, aero, and other improvements when used in a combined strategy can have significant improvements.

With modern power plant technology the idea of a smaller engine working directly through a differential for cruising speed efficiency would probably provide some improvement to a limited degree at somewhat of a weight penalty.

My preference is capacitive storage and engine pulse and glide to the storage reservoir, with infinitely variable drives to the individual wheels and high efficiency regenerative braking for those situations where stop and go is the only option.

Engine size is not really a great factor if you consider that greater engine power would reduce the fuel consuming recharging of the capacitive storage system. In other words the current propensity in US cars to have much more engine than you really need, does not automatically mean a mileage penalty, if the fuel consuming percentage of run time is a smaller percentage of total vehicle operational time in proportion to the difference in available maximum engine power.

regards
Mech
  Reply With Quote
Old 06-24-2010, 06:24 PM   #4 (permalink)
Basjoos Wannabe
 
ShadeTreeMech's Avatar
 
Join Date: Apr 2009
Location: Arkansas
Posts: 870

The Van - '97 Mercury Villager gs
90 day: 19.8 mpg (US)

Lyle the Kindly Viking - '99 Volvo V70
90 day: 25.82 mpg (US)
Thanks: 174
Thanked 49 Times in 32 Posts
The pruis may weigh only 165 pounds more, but how much do those packs cost? Lead acid is the only affordable source I can think of and they're not cheap either!

Funny thing about my Max is how mpgs seem to go up around 80 mph.....wonder if ~2500 rpms is the magic area of the BSFC?
__________________
RIP Maxima 1997-2012


Quote:
Originally Posted by jamesqf View Post
I think you missed the point I was trying to make, which is that it's not rational to do either speed or fuel economy mods for economic reasons. You do it as a form of recreation, for the fun and for the challenge.
  Reply With Quote
Old 06-24-2010, 07:09 PM   #5 (permalink)
Administrator
 
Daox's Avatar
 
Join Date: Dec 2007
Location: Germantown, WI
Posts: 11,104

CM400E - '81 Honda CM400E
90 day: 51.49 mpg (US)

Daox's Grey Prius - '04 Toyota Prius
Team Toyota
90 day: 49.53 mpg (US)

Daox's Insight - '00 Honda Insight
90 day: 64.33 mpg (US)

Swarthy - '14 Mitsubishi Mirage DE
Mitsubishi
90 day: 56.69 mpg (US)
Thanks: 2,427
Thanked 2,477 Times in 1,495 Posts
Program in an x-gauge to show you average mpgs. That will show you the truth. You will see higher mpgs at higher speeds when you go down a hill or anytime you let off the gas because you are traveling faster. Travel faster over time and I can pretty much guarantee worse mileage.
__________________
Current project: A better alternator delete
  Reply With Quote
Old 06-24-2010, 07:38 PM   #6 (permalink)
Master EcoModder
 
Patrick's Avatar
 
Join Date: Apr 2008
Location: Northern Florida, USA
Posts: 510

Hot Tamale - '10 Toyota Prius III
Thanks: 27
Thanked 96 Times in 70 Posts
Quote:
Originally Posted by ShadeTreeMech View Post
The pruis may weigh only 165 pounds more, but how much do those packs cost? Lead acid is the only affordable source I can think of and they're not cheap either!

Funny thing about my Max is how mpgs seem to go up around 80 mph.....wonder if ~2500 rpms is the magic area of the BSFC?
The Prius packs aren't cheap, but they're NiMh, not Li-Ion, so they're more reasonable. And with the number of Prius' that have been sold, economies of scale should come into play to lower the price. I guess the real question is, can you build the extra-engine hybrid cheaper than Toyota can build a Prius?
  Reply With Quote
Old 06-25-2010, 01:50 AM   #7 (permalink)
Wannabe greenie
 
Join Date: Aug 2008
Location: Yorba Linda, CA
Posts: 1,098

The Clunker (retired) - '90 Honda Accord EX sedan
Team Honda
90 day: 29.49 mpg (US)

Mountain Goat - '96 Ford Ranger XLT 4x4 SuperCab
90 day: 18 mpg (US)

Zippy - '10 Kymco Agility 125
90 day: 65.03 mpg (US)
Thanks: 5
Thanked 53 Times in 40 Posts
Quote:
Originally Posted by Patrick View Post
The Prius packs aren't cheap, but they're NiMh, not Li-Ion, so they're more reasonable. And with the number of Prius' that have been sold, economies of scale should come into play to lower the price. I guess the real question is, can you build the extra-engine hybrid cheaper than Toyota can build a Prius?
And can that second engine go 100,000+ miles without any maintenance at all, to include oil, and meet current emissions standards?
__________________

  Reply With Quote
Old 06-25-2010, 06:36 AM   #8 (permalink)
Master EcoModder
 
NeilBlanchard's Avatar
 
Join Date: May 2008
Location: Maynard, MA Eaarth
Posts: 7,854

Mica Blue - '05 Scion xA RS 2.0
Team Toyota
90 day: 42.48 mpg (US)

Forest - '15 Nissan Leaf S
Team Nissan
90 day: 156.46 mpg (US)

Number 7 - '15 VW e-Golf SEL
TEAM VW AUDI Group
90 day: 155.81 mpg (US)
Thanks: 3,351
Thanked 2,860 Times in 1,798 Posts
The electric motor in most cars will go far longer than the ICE. And they require virtually no maintenance.
__________________
Sincerely, Neil

http://neilblanchard.blogspot.com/
  Reply With Quote
Old 06-26-2010, 02:55 AM   #9 (permalink)
Engineering first
 
bwilson4web's Avatar
 
Join Date: Mar 2009
Location: Huntsville, AL
Posts: 780

14 i3-REx - '14 BMW i3-REx
Last 3: 45.67 mpg (US)

17 Prime Plus - '17 Toyota Prius Prime Plus
90 day: 58.25 mpg (US)
Thanks: 73
Thanked 192 Times in 123 Posts
Hi,

You may be ready to understand the drag formula:
Quote:
Originally Posted by ShadeTreeMech View Post
. . .
While driving my max, I noticed the scan guage tells me only 50 hp (or less) is required to keep the vehicle moving. I've also learned that pumping losses are one of the biggest fuel economy disadvantages of the throttle body equipped gas engine.
. . .
One of the earlier, vehicle drag formulas had just two terms:
D = 190 + 0.42*(V*V) :: NHW11 drag formula from Toyota sales material
D = C + B*V + A*(V*V) :: the formula the EPA now uses

V = velocity
A = constant 1 (aerodynamic drag)
B = constant 2 (typically transaxle drag)
C = constant 3 (usually rolling drag)
190 = NHW11 rolling drag, typical
0.42 = NHW11 coefficient of drag times area, typical
Regardless of the drag formula used, you can calculate the power needed to sustain a vehicle speed. So let's see how it works in the real world:
  • Drag power line (red) - the power needed to keep the car rolling on a flat, no wind condition in HP on the right axis.
  • Motive fuel needed, blue - the amount of fuel needed per mile to keep the car rolling at that given speed assuming 31% conversion of gasoline to motive energy on the left axis.
  • Motive and vehicle overhead fuel needed, gray - the amount of fuel needed per mile to keep car rolling and powered assuming 31% conversion efficiency. This includes the idle overhead of a car which is independent of speed.
The point is drag, both rolling and aerodynamic are the primary forces the engine(s) have to overcome. But at low speeds, vehicle overhead becomes the limit. What you are proposing, carried to its logical extreme, is a very large number of small but very efficient engines. These engines come on as needed to provide motive power or are off. The two-engine solution, one being half the power of the other, is a similar solution. But the hybrid uses another trick.

Our hybrid-electric cars have a broad power range, efficient engine but there are times when the engine power provided exceeds the vehicle demand while remaining efficient. In these cases, the engine banks this extra power in the battery so later, the engine can be off instead of running in lower power, inefficient bands.

The battery can do one more trick that no fuel engine can accomplish, bank kinetic energy from either braking or while descending a hill. But this could also be done using a hydraulic system, which has some desirable, peak power capabilities over current battery storage systems. My understanding is some formula one cars are looking at a flywheel-electric system but no consumer production versions, yet.

Universally, reduce drag both rolling and aerodynamic, and everyone wins. But in power systems, we're all fighting the 2nd Law. The hybrid has the ability to bank power and extend their efficient power bands while minimizing inertial losses.

Bob Wilson
__________________
2019 Std. Range Plus Model 3 - 134 MPG3 || 2014 BMW i3-REx - 117 MPGe, 39 MPG
JuiceBox 40 Pro (240 VAC, 40 A), KHONS portable (120-240 VAC, 12-32 A)
Retired engineer, Huntsville, AL (five times AutoPilot saved.)
  Reply With Quote
Old 06-26-2010, 05:36 AM   #10 (permalink)
The PRC.
 
Join Date: Oct 2009
Location: Elsewhere.
Posts: 5,304
Thanks: 285
Thanked 535 Times in 384 Posts
F1 cars used a system called KERS (Kinetic Energy Recovery System) which could store regenerative energy in a flywheel or battery system (depending on team) and release it as extra power when the driver hit a button. Its advantages were a burst of speed to help overtaking which is a criticism of F1 at the moment - the cars are so closely matched that overtaking is rare.

The system wasn't universally liked and a lot of teams would run a car with and one without and often find the advantage on long straights was nullified by the extra weight on corners. Some teams didn't bother at all.

It was abandoned after the end of the 2009 season.

Other systems have also been used including hydraulics, air compression etc.

__________________
[I]So long and thanks for all the fish.[/I]
  Reply With Quote
Reply  Post New Thread


Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Are hybrid SUVs a good or bad thing? SVOboy Hybrids 71 05-05-2017 03:24 PM
Malibu Hybrid bennelson Hybrids 17 12-21-2011 10:57 PM
Milwaukee Hybrid Group Meet 3-28-09 Daox Events & Meet-ups 1 03-28-2009 09:04 PM
Honda Begins Use of Class 8 Hybrid Truck Q1000 Hybrids 0 03-11-2009 07:55 PM
Click and Clack puzzler: SUV or Hybrid? A Familial, MPG Conundrum! MetroMPG General Efficiency Discussion 0 12-20-2007 01:09 PM



Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com