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I was using the FAS relay system to kill the engine last night, and as always the DC/DC converter shuts off, and the 12V battery had to run the lights, the forced cooling for the Ewheel, and the main climate control fan to force cool the IMA batteries. It was a long light, so The head lights began to dim, and I had to restart the engine to get the DC/DC to start up and help with the 12V loads.
We need to determine how to keep the DC/DC running when in FAS. It stays on during regular AS, but not when in FAS.
Anyone want to check out the DC/DC control lines to determine which line we need to fool.

Does the DC-DC stop during normal fuel cut? Like when driving along and you take your foot off the gass pedal completely but leave the transmission engaged ... the engine begins to brake the car ... but it also enters fuel cut mode.... if the DC-DC works during this fuel cut mode... than there might be an alternative way to FAS that will allow the DC-DC to continue...

Speaking of FAS... does FAS connect to the stock fuel cut relay shown on page 22-7 of the service manual?

Hi Mike:

___What about a FAS switch going after the Injector’s alone as most install them?

___Good Luck

___Wayne

This is in an Insight? Why does the DC/DC quit at all when you're
in a FAS, that doesn't make any sense? It certainly keeps
making zoobs in the Prius. That sounds like a *bug*.
.
_H*

This is in an Insight? Why does the DC/DC quit at all when you're
in a FAS, that doesn't make any sense? It certainly keeps
making zoobs in the Prius. That sounds like a *bug*.
.
_H*


??? I was not aware anyone had ever made a FAS for the prius ???

Both stop fuel to the ICE when the car's computer wants them to , But I thought that the FAS ability to manually stop / cut the fuel to the ICE when the driver wanted no matter what the on-board computer wants was something people had only put on Insights.... hmmmm .... Interesting??? well ... I learn something knew everyday.... I will have to do some reseach for fun to see how the Prius FAS connects.

As I see it, the DC/DC is always on, when running, in fuel cut, and autostop. When the car stalls as in FAS (forced Auto Stall), the DC/DC is turned off.
Wayne,
The FAS relay system we use only cuts the 3 fuel injector return wies, and holds the clutch signal lo as though the clutch was in, so you do not have to hold it in. pretty much the same as the 3 pole switch that Calpod is using but with Highwaters latching clutch relay
The fuel injector lines are only momentarily opened until the car stalls for lack of gas, then the lines are re-connected so the auto start for lack of brake vacuume, depression of gas pedal, or shifting into gear will start it automatically.
It seems that in the car stalled logic they cut the DC/DC. I believe there is a single DC/DC enable signal that controlls this. We may be able to tie this enable signal to the clutch override switch and keep the DC/DC on.
I have not had time to dig into the electrical service manual to see if it could be that simple.
A stalled engine could be for many reasons, so they likely cut the DC/DC for safety reasons, or to prevent depletion of the HV Battery?
:confused:

Well, I guess what I mean by FAS in a Prius, is simply removing
one's foot from the go-pedal. Poof, FAS, if you're under 42
mph. But the whole system knows what's going on. For 42 and up,
fuel-cut mode with the ICE still spinning, whereupon warp stealth
is the zero-consumption option.
.
One can use the "EV button" Prius mod to get around some of
the excess ICE-running in warmup mode, too, until the thing finally
gets up to 70 deg C and you can get into "stage 4" full hybrid
operation where it doesn't keep trying to idle.
.
And the DC/DC converter is unaffected by any of this...
.
_H*

Thats the difference between engineering in a full EV mode like the Prius, and needing to hack the system to get that function on the Insight which was not designed to operate that way.
:rolleyes:

hey mike!

in my insight, after a FAS, if the conditions are right the car goes into AS, with the green light at the bottom of the tach, and the dc-dc comes back on.

btw, i love my MIMA!!!

Hi Andy
Mine does that once in a while,but not always.
With the Ewheel, I can drive for miles, and at night with the DC/DC off, I have had to start the motor just to enable the real AS, drive to a stop, and once I am in AS with the DC/DC on, then I can cruise with just the electric.
I guess I will need to pull out the manual and do some more playing.
;)

you know mike... instead of restarting the ICE and useing gas... you could just put it in gear if the RPMs are 2,000 or over the car usually enters Fuel cut mode.... the ICE will produce some drag.... but in higher gears like 4th and 5th it isnt' much drag and that might enable you to use less gas then restarting the ICE ....

I wonder if there is a way to do a Forced Stall ( FAS ) type of system instead of through the injectors ... use the fuel cut system the car does when you take your foot off the gas at speed and in gear??? MIMA can push the car around some like this and I bet your 5th wheel would be able to as well...


another option you woudl have is before you pull out be in Auto stop which keeps the DC-DC running and then just accelerate up from there.... I have been in Auto Stop up to like 30 and 40 MPH some times.... kicks in bellow 20 MPH when the Car is warmed up and thinks I am coming to a stop but if going down a hill I can then accelerate in Auto Stop instead of useing FAS or the in gear fuel cut mode.

The waiting till I am real autostop is how I have been using the Ewheel, but once the ICE restarts, the FAS usually is to only way to kill the ICE while moving, so if I need the brakes a few times, the engine restarts, and then I am stuck with only bad options. Stop to do another AS, let the ICE idle, or drive with no DC/DC after doing the FAS.
The best solution would be to enable the DC/DC, but I don't want to cook the 12V battery, by overcharging, and it is not clear where the voltage regulation takes place. Just need to get set up, and do a few test and it should become much clearer as to the best solution.

If the ICE could produce more charge while idling, I could just leave the ICE idle while driving with the Ewheel, and be charging the IMA batteries at the same time with the "wasted" energy. Another reason to crack this nut.;)

since the stock DC-DC system is just a module... could it be controlled from something other than the stock control system ??? That way when you are in FAS for long periods of time you can just manually turn the stock DC-DC system on to recharge the 12V every now and then... I admit I dont' know enough about how the stock system controls the DC-DC system to know if the stock DC-DC module can be activated on its own or not... But I thought it was setup so that the stock honda control system just cuts power to it when it wanted it to shut down the stock DC-DC system... and if that is the case then a high voltage diconnect type of switch like the one you use the connect and disconnect the booster system the the stock batteries could be used to feed current to the stock DC-DC system directly from the stock battery pack when you want to... like in long FAS type operation.

Ian
You are correct about the DC/DC, I see that I posted my last message in the wrong thread, it should have been the one about using the IMA for emergency generation.
Sorry.

here's another question.... allot of DC-DC modules can go both ways.... I know the stock Honda DC-DC system is only designed to go one way from the high 144+V pack to the lower 12V battery.... is this a limit of the stock DC-DC module itself ... or is it a limit of how the stock DC-DC module is wired / used ???

Ian
Any DC/DC converters that work both ways, are really two converters one for each direction.

I Think the stock DC-DC module just does its thing when you give it power.... and the stock system cuts the DC-DC module by sutting power to it... so if you give it power from the high voltage output of the booster DC-DC modules it shoudl down convert for you.... a high voltage disconect like the ones used for the DC-DC booster modules to the stock battery would be needed to disconnect this when you don't need it....

Another option would be to just use one of the Victor DC-DC modules to run a charging current from the 48V booster pack to the 12V accessory battery.

The voltage regulation for 12V charging is my only concern, and it makes sense that it would be part of the DC/DC function.
I have a 48V to 12V bat mod just for that purpose.

There is now ~3000 miles on the FAS DC/DC enabled feature on my Insight. No problems that I can see. Regualtion seems to be fine. Holds ~14.1v when in FAS, and with ICE on holds ~13.85. The DC/DC will cut out when doing a 1/2/3 shift, or when lugging it in factory IMA mode causes assist to come on. Must be a manifold pressure thing.

Also the battery and brake lights do not illuminate anymore when doing a FAS. Only the oil pressure indicator is on. The oil pressure looks to be a one wire fix should one desire to eliminate that. Page 81 in the ETM shows one wire from the pressure switch to the gauge assembly, and looks to be grounded when there is oil pressure. Might be as easy as grounding it when in FAS. This wire goes thru 2 connectors that are in the shift console near the MIMA board, easy to get to.

Mike and I had talked about the need for sustaining vaccume in a long FAS or an EV only mode. Provided one has a 12v signal coming out of the clutch hold relay that should be easily done with the addition of a small pump.

Randall

Randall
Thats great news. I guess I will have to fix my DC/DC like you did yours as soon as possible.

Still hacking at my heating system, as the frosty mormings are becoming more frequent. I am almost ready for the final piping pressure testing before refilling with fluid, but I want to go carefully, as it is major surgery once it is filled and running.
http://pages.cthome.net/genesisone/solar_page.htm

like you did yours

Because I asked for your help.

And Thanks Mike.

Randall

Always ready to help when it involves saving gas, happy that it worked out so well.