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stillsearching · 05-12-2013, 12:04 PM

I think I posted something similar before but as time goes i'm refining various ideas in my head on various things...

What is your wishlist for what a mileage-centric computer would show you?

I'm hoping at some point, whether it's by myself, or working with others, or whatever it is, to figure out some kind of a project for coming up with such a thing. Knowing what it should display is kind of the first step. Because I expect to use such a thing both under conditions of towing as well as going uphill (long runs into the mountains) my needs are more demanding than most.

What I most would want would be a color 2d LCD monitor showing me the specific fuel consumption map of the car - as well as where on that map I currently am. I want it to replace the tachometer, for left to right, and to show me my actual throttle position, for up to down, so I can actually see where I am and alter my driving accordingly. I also want it animated in response to forced induction boost levels - because the SFC map is different under 50% throttle position and 2000rpm at 2psi than it is at 8psi - and the load can change without me touching the throttle with things like turbochargers. I'm hoping with enough exposure, i'll have memorized and be able to reliably predict, so that I can stay in the "well" of lowest SFC - applying P&G driving technique under any relevant conditions including towing things uphill.

That would be a 2nd part of this too actually - a pulse and glide computer. I'm still not sure what it should show or exactly how to calculate this, but i'd want something that could, for instance, help me figure out the perfect speed range to P&G for under any condition - including which conditions under which to abandon it. Basically I want a display showing me what i'd term red, yellow and green zones. Green means that for having done the math in the past, the total cost-per-mile (this is more than mileage, a 5% fuel efficiency increase and a 20% higher maintenance figure is a loss) is an Absolute Win under these conditions. Yellow would mean that i'm trading maintenance costs for fuel efficiency - yes it's better fuel efficiency and maybe i'm low on gas and everything is closed at 3am and i'm trying to just get to the next open gas station. : P Red would mean no, you are better off under steady state cruising rpm.

The thing is that i'm not sure how to best calculate this under conditions of towing. The aerodynamic load changes based on what you are pulling, and the weight could vary all over the map. The environmental conditions of uphill or downhill, of stiff front winds or side winds or tail winds changes it. Of slogging through snow vs running on clean roads. And everything changes if i'm sharing the road with others so that I cannot go as fast, or coast down to as slow, as I would like to. My goal would be to figure out a ruleset that can pretty accurately predict all the above, showing me the red/yellow/green conditions so that all I have to focus on is just the driving when i'm actually driving. I don't want to be running numbers in my head in heavy traffic.

It is possible that a third purpose for such an MPG computer could be research and recording - things like coast down tests. I want to try an aeromod so it keeps track of two separate runs so I can see whether it reduced drag and how much, and an estimated fuel savings if I keep that mod on. This could be more useful for say if i'm hauling something aerodynamically awkward I just picked up, and therefore cant CAD model it in on the computer to figure out an ideal shape. I'm trying to bring it home at 25mpg instead of 18mpg and all I have with are my sheets of cardboard and duct tape. I could do a few simple "street tests" and come down with an approximation.

To that i'd probably add some maintenance tracking to boot if i'm going to computerize that far... since this is about cost-per-mile, not exclusively fuel efficiency, with netbooks being as cheap as they are, I would just have a dedicated netbook, normal PC software, something anyone can download and add to and similar, along with some kind of interface to OBD 1/2/3 or other sensors for those who don't have computerized diagnostics but still want to use it to calculate the mileage. I'd want to be able to use real measured SFC maps along with best guess or extrapolated ones - so if you dyno your eco-car you can use the exact results of a test, or you can look up factory figures and even if you may not be in perfect tune or that exactly you can get pretty close based off the engineering team's results for whatever you drive.

You might as well add record tracking - type in how many gallons you filled up to track what you actually are getting. Maybe have it track certain conditions of load, average speed and similar to give you a longer term view. At some point you might even be able to turn that data logging into predictive ability - ie a data analysis that shows that you are normally towing in X rpm range most of the time, and going from a 3.73 to a 3.48 rear axle ratio would put the engine more in the sweet spot, or that you spend so much time in P&G mode vs steady state mode so it would help figure out what changes are worth making to your total setup.

So thats my wishlist, what would you want to add to that if you could?

05-12-2013, 12:04 PM	#1 (permalink)
stillsearching EcoModding Apprentice Join Date: Dec 2011 Location: Minnesota Posts: 201 Thanks: 45 Thanked 8 Times in 7 Posts	what would your ideal MPG computer be? I think I posted something similar before but as time goes i'm refining various ideas in my head on various things... What is your wishlist for what a mileage-centric computer would show you? I'm hoping at some point, whether it's by myself, or working with others, or whatever it is, to figure out some kind of a project for coming up with such a thing. Knowing what it should display is kind of the first step. Because I expect to use such a thing both under conditions of towing as well as going uphill (long runs into the mountains) my needs are more demanding than most. What I most would want would be a color 2d LCD monitor showing me the specific fuel consumption map of the car - as well as where on that map I currently am. I want it to replace the tachometer, for left to right, and to show me my actual throttle position, for up to down, so I can actually see where I am and alter my driving accordingly. I also want it animated in response to forced induction boost levels - because the SFC map is different under 50% throttle position and 2000rpm at 2psi than it is at 8psi - and the load can change without me touching the throttle with things like turbochargers. I'm hoping with enough exposure, i'll have memorized and be able to reliably predict, so that I can stay in the "well" of lowest SFC - applying P&G driving technique under any relevant conditions including towing things uphill. That would be a 2nd part of this too actually - a pulse and glide computer. I'm still not sure what it should show or exactly how to calculate this, but i'd want something that could, for instance, help me figure out the perfect speed range to P&G for under any condition - including which conditions under which to abandon it. Basically I want a display showing me what i'd term red, yellow and green zones. Green means that for having done the math in the past, the total cost-per-mile (this is more than mileage, a 5% fuel efficiency increase and a 20% higher maintenance figure is a loss) is an Absolute Win under these conditions. Yellow would mean that i'm trading maintenance costs for fuel efficiency - yes it's better fuel efficiency and maybe i'm low on gas and everything is closed at 3am and i'm trying to just get to the next open gas station. : P Red would mean no, you are better off under steady state cruising rpm. The thing is that i'm not sure how to best calculate this under conditions of towing. The aerodynamic load changes based on what you are pulling, and the weight could vary all over the map. The environmental conditions of uphill or downhill, of stiff front winds or side winds or tail winds changes it. Of slogging through snow vs running on clean roads. And everything changes if i'm sharing the road with others so that I cannot go as fast, or coast down to as slow, as I would like to. My goal would be to figure out a ruleset that can pretty accurately predict all the above, showing me the red/yellow/green conditions so that all I have to focus on is just the driving when i'm actually driving. I don't want to be running numbers in my head in heavy traffic. It is possible that a third purpose for such an MPG computer could be research and recording - things like coast down tests. I want to try an aeromod so it keeps track of two separate runs so I can see whether it reduced drag and how much, and an estimated fuel savings if I keep that mod on. This could be more useful for say if i'm hauling something aerodynamically awkward I just picked up, and therefore cant CAD model it in on the computer to figure out an ideal shape. I'm trying to bring it home at 25mpg instead of 18mpg and all I have with are my sheets of cardboard and duct tape. I could do a few simple "street tests" and come down with an approximation. To that i'd probably add some maintenance tracking to boot if i'm going to computerize that far... since this is about cost-per-mile, not exclusively fuel efficiency, with netbooks being as cheap as they are, I would just have a dedicated netbook, normal PC software, something anyone can download and add to and similar, along with some kind of interface to OBD 1/2/3 or other sensors for those who don't have computerized diagnostics but still want to use it to calculate the mileage. I'd want to be able to use real measured SFC maps along with best guess or extrapolated ones - so if you dyno your eco-car you can use the exact results of a test, or you can look up factory figures and even if you may not be in perfect tune or that exactly you can get pretty close based off the engineering team's results for whatever you drive. You might as well add record tracking - type in how many gallons you filled up to track what you actually are getting. Maybe have it track certain conditions of load, average speed and similar to give you a longer term view. At some point you might even be able to turn that data logging into predictive ability - ie a data analysis that shows that you are normally towing in X rpm range most of the time, and going from a 3.73 to a 3.48 rear axle ratio would put the engine more in the sweet spot, or that you spend so much time in P&G mode vs steady state mode so it would help figure out what changes are worth making to your total setup. So thats my wishlist, what would you want to add to that if you could?