Top five things your OBDII port can tell you about ecodriving
 

I am working on a project to produce a low cost OBDII port reader that will give drivers the information they need to know to change their driving behaviour.

To that end there has been a discussion of which outputs we should be reading off the OBDII.

I a looking at Speeding, hard acceleration and hard breaking. The last two that have been suggested is fuel economy and time spent idiling.

I am interested in hearing what others think should be our final two points.

comments?

Andrew

Not sure I understand what exactly you're looking at but......

Speeding might not be an FE killer. If you are talking about driving faster than 60 MPH then yes. Driving 40 in a 30 might return better FE if the shift point is right.

Hard acceleration is not necessarily a FE killer and can return as good if not better returns on FE depending stage lenght.

For the general masses

Instantaneous FE readout
Throttle position
Digital MPH readout
Ignition timing
RPM

Welcome to the site.

Distantman -

Welcome to EM!

Lazarus -

The instant-FE would be a calculated value, yes? It wouldn't come from the OBD-II protocol itself. I think the engine LOAD parameter would be a better 5th value if you don't count instant-FE.

CarloSW2

Carlos,
You might be right about the LOAD but I was thinking for the general masses that RPM would be much easier to understand. Most cars now a days don't even have a tach :( and are automatics. With RPM it would be very easy to see where shift point occur so that you could travel at the best speed with the lowest rpm for that speed zone.

Lazarus -

I would keep RPM too. This would be my list of 5 OBD-II parameters, with Scangauge acronyms in parenthesis :

But now I see the confusion with the original post :

In the above, there is the statement "reading off the OBDII". There is no direct parameter for "hard acceleration" or "hard breaking". You have to interpret the rate of change in MPH, possibly in conjunction with the TPS and/or LOD, for both of those. The same with fuel economy (complicated algorithm) and time spent idling (RPM at 0 MPH and 0 TPS).

CarloSW2

...how about a calculated BSFC "mapping" using Load, MAP/MAF and RPM?

...something to "show" you when you're "in" the best BSFC area of the engine loading?

Old Tele man -

That's actually my theory on how the ScanGauge works. I think it has a generic BSFC chart that "adapts" to the car over time. I thought that it would only need LOAD and RPM for BSFC. Why would it need MAP/MAF? Does the MAP/MAF tell you where the "hills and valleys" are in the BSFC?

CarloSW2

...as I understand it, Manifold Air Pressure (MAP) and Mass Air Flow (MAF) basically tell you how "deeply" the engine is breathing in air, MAP by differential pressure (intake vs. outside air) and MAF by "how much" air is being sucked (breathed) in.

...hence, in my mind, they're fancy vacuum gauges, with MAP being most like a vacuum gauge. MAF is "mass" based rather than "pressure" based.

Perhaps non-obvious, but the ScanGauge readout I find most useful is coolant temperature. With the Insight, at least, the built-in temperature gauge is worthless. (Shows 5 bars at about 140F, and maybe 6 driving up a long mountain on a hot day.) In colder weather, the engine hardly ever gets to normal operating temperature without a radiator block, so is operating at less than best efficiency. So looking at an accurate coolant temp tells me it's time to put in a larger or smaller block.

jamesqf -

That's a good point. I was focusing only on values that are directly related to FE, but coolant temp is an indirect indicator of FE. It's one of my "always-there" instant gauges on the scangauge.

CarloSW2