MPS: Why couldn't we do this..., a theorectical question |
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MPS: Why couldn't we do this..., a theorectical question |
drewvw |
Jun 29 2006, 08:55 AM
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#1
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new england car guy Group: Members Posts: 1,631 Joined: 24-February 06 From: Boston, MA Member No.: 5,630 Region Association: North East States |
Was just talking to evil about a potential replacement for the MPS and came up with the following question:
Is it possible to replace the MPS with some sort of chip / solid state component that emulates the readings that the MPS gives off throughout the range, but is instead driven by engine RPM, throttle position, etc? If that wouldn't work, why? I don't pretend to know much about djet, but it dawned on me that I could program a chip that maps various readings to the rpm range. Might take a bit to get the curve right for part throttle response but...is it doable? |
Demick |
Jun 29 2006, 08:58 AM
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#2
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Ernie made me do it! Group: Benefactors Posts: 2,312 Joined: 6-February 03 From: Pleasanton, CA Member No.: 257 |
Not a new concept. Just nobody knows how to do it - yet. Hopefully someone will figure it out. But it isn't simple by any means. Read the last few posts of this thread:
mps thread |
Allan |
Jun 29 2006, 08:58 AM
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#3
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Teenerless Weenie Group: Members Posts: 8,373 Joined: 5-July 04 From: Western Mesopotamia Member No.: 2,304 Region Association: Southern California |
Megasquirt?
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drewvw |
Jun 29 2006, 09:00 AM
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#4
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new england car guy Group: Members Posts: 1,631 Joined: 24-February 06 From: Boston, MA Member No.: 5,630 Region Association: North East States |
I'm sure its been discussed many times over the years, the conversation evil and I were having just got me thinking. Being a programmer, I think I could build something that could do this. |
Thack |
Jun 29 2006, 09:02 AM
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#5
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Member Group: Members Posts: 283 Joined: 1-June 05 From: Houston, Tx Member No.: 4,182 |
For one the fuel required is measured by need/load. When you have your foot to the floor, the chip would not know how much fuel is required because the rpms do not immediately rise with the throttle opening. You could design it that way if you changed a few other things.
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drewvw |
Jun 29 2006, 09:10 AM
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#6
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new england car guy Group: Members Posts: 1,631 Joined: 24-February 06 From: Boston, MA Member No.: 5,630 Region Association: North East States |
I see what your saying Thack. I revised my original post to include throttle position as an input as well.... stamping a basic chip to do something like this is not tough to do at all...finding the correct algorithim for the output however... |
Thack |
Jun 29 2006, 09:20 AM
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#7
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Member Group: Members Posts: 283 Joined: 1-June 05 From: Houston, Tx Member No.: 4,182 |
It sounds like you are on the right track. Maybe you can develop what you can and then someone else can come up with the engine vaccuum interpolation. Because when you go uphill and need more fuel to maintain speed that has to be addressed also.
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drewvw |
Jun 29 2006, 09:22 AM
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#8
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new england car guy Group: Members Posts: 1,631 Joined: 24-February 06 From: Boston, MA Member No.: 5,630 Region Association: North East States |
yeah exactly, that was the piece I was missing. You need to measure load somehow... |
KenH |
Jun 29 2006, 09:55 AM
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#9
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Senior Member Group: Members Posts: 680 Joined: 16-January 03 From: Gilroy, CA Member No.: 156 |
MAP sensor to measure vacuum as the MPS does.
Software to convert MAP data to match MPS info. This is not a linear curve. Need a different curve for each of the 3 MPS. Interface to "Brain" that looks like the MPS output inductor. Ken |
lapuwali |
Jun 29 2006, 09:56 AM
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#10
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Not another one! Group: Benefactors Posts: 4,526 Joined: 1-March 04 From: San Mateo, CA Member No.: 1,743 |
Read my blog. One of the earlier posts discusses this. The short version is that by the time to put together the electronics to emulate the MPS, you're 90% of the way to a full fuel ECU, so you might as well just spend the much smaller amount of money on a Megasquirt, which uses a solid-state pressure sensor, and thus doesn't need the MPS.
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