Using DFCO to increase your MPG

[Pavel Olavich]

Honda uses the term "Grade Logic"....what does Toyota call their's? Anyone know?

[ECHOKnight2000]

Originally Posted by Pavel Olavich

Honda uses the term "Grade Logic"....what does Toyota call their's? Anyone know?

I think Toyota referrs to it as uphill/down hill shift logic. For automatics at least. The engine won't gear hunt as much going down hill or up hill (granted if you're gradually going up a hill. I don't know if that has to do with what we're talking about but I bet it has some relation as far as DFCO.

I don't have a Yaris but the ECHO (auto) has a similar set up obviously not the up to date version like the Yaris. I have one question though. I have a scanguage II and I have one of the read outs on closed or open loop. The fuel loop or whatever...anyway I read that when the loop is open it actually means the ECU cuts off fuel to the engine to save gas...so like when I cruise from about 55 and up and just let the car go even in drive the loop opens for a bit until I get to a certain speed. It really opens up either when I floor it or downshift to a lower gear like coming off the highway. I was wonder if this is DFCO cause it cuts off fuel or at least I think it does. Can anyone help me on this who knows about cars? Thanks!

[Pavel Olavich]

Originally Posted by ECHOKnight2000

I think Toyota referrs to it as uphill/down hill shift logic. For automatics at least. The engine won't gear hunt as much going down hill or up hill (granted if you're gradually going up a hill. I don't know if that has to do with what we're talking about but I bet it has some relation as far as DFCO.

I don't have a Yaris but the ECHO (auto) has a similar set up obviously not the up to date version like the Yaris. I have one question though. I have a scanguage II and I have one of the read outs on closed or open loop. The fuel loop or whatever...anyway I read that when the loop is open it actually means the ECU cuts off fuel to the engine to save gas...so like when I cruise from about 55 and up and just let the car go even in drive the loop opens for a bit until I get to a certain speed. It really opens up either when I floor it or downshift to a lower gear like coming off the highway. I was wonder if this is DFCO cause it cuts off fuel or at least I think it does. Can anyone help me on this who knows about cars? Thanks!

I think DFCO and Grade-Logic are two completely different processes, and are not related, although this is not to say that they don't cooperate together.

As for open/closed loop, when open, the ECU uses "maps" for determining ignition, and other stuff. When the loop is closed, the ECU uses realtime calculations to control everything.....I could be wrong, so maybe someone has a much better explanation, as my sources are a bit flakey on this. I write this because I don't want to spread info if I'm not 100% sure about.