Fuel Injector Shut-Off
Active Enthusiast
Joined: Jan 2007
Posts: 102
From: Kansas City, MO
Re: Fuel Injector Shut-Off
Rick, what was your speed?
Are you talking instant Econ, or average Econ?
If you had more than zero, but less than 0.1L it would still read an average of 0.0L.
0.0L in neutral works, if you are in EV.
If you are seeing 0.0L in N with engine spinning, how is that possible?
Try a few more times if you can, and see if you can get consistant results.
Are you talking instant Econ, or average Econ?
If you had more than zero, but less than 0.1L it would still read an average of 0.0L.
0.0L in neutral works, if you are in EV.
If you are seeing 0.0L in N with engine spinning, how is that possible?
Try a few more times if you can, and see if you can get consistant results.
It' not easy to force the run-up (I tried a few times yesterday with no luck), but I'll try again and let you know.
-- Rick
Ridiculously Active Enthusiast
Joined: Aug 2006
Posts: 859
From: Waterloo, ON
Re: Fuel Injector Shut-Off
GaryG — Assuming that the FEH behaves similarly to the TCH in this respect (and all the evidence points to this), I'd like to correct some possible misconceptions.
(a) The reason for spinning the ICE when coasting at speed is to protect MG1 from over-revving. If the ICE is still powered (burning fuel) then it spins itself, and nothing needs to be done, since MG1 will not over-rev. But, if fuel-cut is in effect (the ICE is open-loop), it has to be spun by MG1 (a retarding torque is being generated by MG1, and this causes the car's deceleration power to be partially transferred from MG2 to the ICE (the rest goes to charging the NiMH battery if it's not "full"). In 'D' the engine braking is mild, and the ICE spins at its idle speed (~1000 rpm) so that it can be restarted at any time without this being noticed. In 'B' the engine braking is considerable, and much more power is fed to MG1 to spin the ICE much faster (~3000 rpm). Some power still gets sent to the battery if it's not "full." In neither case is power flowing from the battery to MG1 to achieve this.
(b) If you put the vehicle into 'N' at speed, the need to protect MG1 from over-revving still applies, but now no power can flow to MG1 to spin the ICE [as in (a) above], at least in the TCH. So, in 'N,' fuel-cut is aborted, and the ICE must be fired up again to protect MG1. The TCH's display shows that fuel usage has restarted, and ScanGauge shows that the ICE has gone closed-loop again.
(c) The run-up is true engine braking! Power is directed from the wheels to the ICE (via MG2 and MG1) — this is engine braking. It wouldn't make sense to use battery power to spin MG1.
(d) When you see the ICE start up as your FEH's speed goes above ~40 mph during downhill coasting in 'N,' I'd bet that this is not fuel-cut run-up, but rather powered operation (burning fuel) to protect MG1. You should be able to confirm this — look for closed-loop operation and fuel usage.
Stan
(a) The reason for spinning the ICE when coasting at speed is to protect MG1 from over-revving. If the ICE is still powered (burning fuel) then it spins itself, and nothing needs to be done, since MG1 will not over-rev. But, if fuel-cut is in effect (the ICE is open-loop), it has to be spun by MG1 (a retarding torque is being generated by MG1, and this causes the car's deceleration power to be partially transferred from MG2 to the ICE (the rest goes to charging the NiMH battery if it's not "full"). In 'D' the engine braking is mild, and the ICE spins at its idle speed (~1000 rpm) so that it can be restarted at any time without this being noticed. In 'B' the engine braking is considerable, and much more power is fed to MG1 to spin the ICE much faster (~3000 rpm). Some power still gets sent to the battery if it's not "full." In neither case is power flowing from the battery to MG1 to achieve this.
(b) If you put the vehicle into 'N' at speed, the need to protect MG1 from over-revving still applies, but now no power can flow to MG1 to spin the ICE [as in (a) above], at least in the TCH. So, in 'N,' fuel-cut is aborted, and the ICE must be fired up again to protect MG1. The TCH's display shows that fuel usage has restarted, and ScanGauge shows that the ICE has gone closed-loop again.
(c) The run-up is true engine braking! Power is directed from the wheels to the ICE (via MG2 and MG1) — this is engine braking. It wouldn't make sense to use battery power to spin MG1.
(d) When you see the ICE start up as your FEH's speed goes above ~40 mph during downhill coasting in 'N,' I'd bet that this is not fuel-cut run-up, but rather powered operation (burning fuel) to protect MG1. You should be able to confirm this — look for closed-loop operation and fuel usage.
Stan
Last edited by SPL; Apr 17, 2007 at 09:52 AM.
Ridiculously Active Enthusiast
Joined: Mar 2006
Posts: 942
From: Ventura, CA
Re: Fuel Injector Shut-Off
On the dash econ gauge, I see 99.9L/Km anytime the engine is running at idle or stopped engine off at a light. I interpret this to mean fuel cutoff is not in effect. When accelerating or cruising then I see realistic numbers for the instantaneous econ. I see 0.0L/Km (closed loop) under various coasting or decelerating scenarios, but more about that later.
I just wondering now if the 99.9L/Km makes sense for idle and stopped (engine off)?
I just wondering now if the 99.9L/Km makes sense for idle and stopped (engine off)?
Ridiculously Active Enthusiast
Joined: Aug 2006
Posts: 859
From: Waterloo, ON
Re: Fuel Injector Shut-Off
econoline — If it says 0 L/100 km (i.e., no fuel usage by the ICE) then surely the ICE must be either not running or else being spun open-loop by MG1 while coasting in fuel-cut mode? If the car is stationary with the ICE running, then yes 99.9 (i.e., infinity) L/100 km is correct. If the ICE is "off" then it ought to read 0 L/100 km (ScanGauge makes the same error).
Stan
Stan
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Joined: Mar 2005
Posts: 3,616
From: All over the Central U.S.
Re: Fuel Injector Shut-Off
No. That does not make sense.
Standing still, engine running, 99.9 L/km makes sense.
Anytime the engine is not running, moving or standing still, it should read 0.0 L/km.
If you came to a stop with engine running, and it shut down after you were already standing still, then maybe a frame of data got frozen, and kept showing 99.9. This is an error. But I have not seen it ( yet ) in mine.
-John
Standing still, engine running, 99.9 L/km makes sense.
Anytime the engine is not running, moving or standing still, it should read 0.0 L/km.
If you came to a stop with engine running, and it shut down after you were already standing still, then maybe a frame of data got frozen, and kept showing 99.9. This is an error. But I have not seen it ( yet ) in mine.
-John
On the dash econ gauge, I see 99.9L/Km anytime the engine is running at idle or stopped engine off at a light. I interpret this to mean fuel cutoff is not in effect. When accelerating or cruising then I see realistic numbers for the instantaneous econ. I see 0.0L/Km (closed loop) under various coasting or decelerating scenarios, but more about that later.
I just wondering now if the 99.9L/Km makes sense for idle and stopped (engine off)?
I just wondering now if the 99.9L/Km makes sense for idle and stopped (engine off)?
Ridiculously Active Enthusiast
Joined: Mar 2006
Posts: 942
From: Ventura, CA
Re: Fuel Injector Shut-Off
I just tested this again today while running errands. Anytime the vehicle is stopped the dash econ gauge goes to 99.9 L/Km following any number of resets that I tried. I can only get 0.0 L/Km in the various coasting scenarios, never while stopped under any conditions.
Anyway, just a curiosity, and not really relevant to this thread.
Anyway, just a curiosity, and not really relevant to this thread.
No. That does not make sense.
Standing still, engine running, 99.9 L/km makes sense.
Anytime the engine is not running, moving or standing still, it should read 0.0 L/km.
If you came to a stop with engine running, and it shut down after you were already standing still, then maybe a frame of data got frozen, and kept showing 99.9. This is an error. But I have not seen it ( yet ) in mine.
-John
Standing still, engine running, 99.9 L/km makes sense.
Anytime the engine is not running, moving or standing still, it should read 0.0 L/km.
If you came to a stop with engine running, and it shut down after you were already standing still, then maybe a frame of data got frozen, and kept showing 99.9. This is an error. But I have not seen it ( yet ) in mine.
-John
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Joined: Mar 2005
Posts: 3,616
From: All over the Central U.S.
Re: Fuel Injector Shut-Off
I'm sorry. I mis-understood. I get what you are saying now.
Yes. Actually, it is a division by zero error. And yes, mine does it, but I have the Navi, so mine says "Max." not 99.9 L/km.
You have "something" divided by zero km traveled, which is impossible or as they say in math, "undefined".
Yes. Actually, it is a division by zero error. And yes, mine does it, but I have the Navi, so mine says "Max." not 99.9 L/km.
You have "something" divided by zero km traveled, which is impossible or as they say in math, "undefined".
Hybrid and Ethanol Expert
Joined: Mar 2005
Posts: 3,616
From: All over the Central U.S.
Re: Fuel Injector Shut-Off
We know energy from regen is cut in "N" right away.
This is actually not always true. At high speeds, and on downgrades, you can get Regen in N. The computer can over-ride your request, if you make a hazardous, or unusual request. Shfiting to N is a computer request, not a mechanical disconnect. If you lived in the Rocky Mountains, you would know this.
The output shaft disengagement in the FEH may have something to do with all this also.
This has never been proven. I'm in fact close to proving to you it is false.
In "N" there is no way we could have wheel engine braking or regen because of the disengagement of the wheels.
Well, yes you can, and yes it does. It may not be often, but the very fact that it CAN happen, is strong, indirect evidence that there is no physical disconnect.
There are only two bridges in Riviera Beach I can test this myself, and I have not been over them in a while.
Right. And there's your problem right there. Your flat driving conditions have lead you to some false assumptions. Come to Colorado, and you'll get a whole different picture.
I have never seen engine run-up that has anything to do with the wheels and real engine braking in my FEH except for regen energy being burned off with MG1 spinning the ICE.
Well I have. And it fact, it is very common. On steep downgrades at highway speeds, the RPM will ramp up when wheel speed increases. This happens in D and in N.
In fact, I read that the FEH ICE RPM has no connection with wheel speed, only positive torque.
You did not understand what they meant, if you are quoting the owner's manual. This refers to the fact the the engine speed can be much HIGHER than vehicle speed, and engine speed can change without a vehicle speed change, but the engine speed can NEVER be LOWER than wheel speed, when MG1 is maxed out. When I'm on the highway, going over 60 MPH, then MG1 is maxed out. Even if I coast in D or shift to N, RPM's will rise as my vehicle coasts faster and faster downhill. Yours would too. You just don't have big enough hills. More evidence there is NO physical disconnect. ( Never mind the lack of ANY sound, vibration, or lurch when shifting in or out of N even at high speeds.
-John
This is actually not always true. At high speeds, and on downgrades, you can get Regen in N. The computer can over-ride your request, if you make a hazardous, or unusual request. Shfiting to N is a computer request, not a mechanical disconnect. If you lived in the Rocky Mountains, you would know this.
The output shaft disengagement in the FEH may have something to do with all this also.
This has never been proven. I'm in fact close to proving to you it is false.
In "N" there is no way we could have wheel engine braking or regen because of the disengagement of the wheels.
Well, yes you can, and yes it does. It may not be often, but the very fact that it CAN happen, is strong, indirect evidence that there is no physical disconnect.
There are only two bridges in Riviera Beach I can test this myself, and I have not been over them in a while.
Right. And there's your problem right there. Your flat driving conditions have lead you to some false assumptions. Come to Colorado, and you'll get a whole different picture.
I have never seen engine run-up that has anything to do with the wheels and real engine braking in my FEH except for regen energy being burned off with MG1 spinning the ICE.
Well I have. And it fact, it is very common. On steep downgrades at highway speeds, the RPM will ramp up when wheel speed increases. This happens in D and in N.
In fact, I read that the FEH ICE RPM has no connection with wheel speed, only positive torque.
You did not understand what they meant, if you are quoting the owner's manual. This refers to the fact the the engine speed can be much HIGHER than vehicle speed, and engine speed can change without a vehicle speed change, but the engine speed can NEVER be LOWER than wheel speed, when MG1 is maxed out. When I'm on the highway, going over 60 MPH, then MG1 is maxed out. Even if I coast in D or shift to N, RPM's will rise as my vehicle coasts faster and faster downhill. Yours would too. You just don't have big enough hills. More evidence there is NO physical disconnect. ( Never mind the lack of ANY sound, vibration, or lurch when shifting in or out of N even at high speeds.
-John
There are things than happen all the time, and there are things that happen rarely.
It's the things that only happen rarely that teach you the most.
Last edited by gpsman1; Apr 17, 2007 at 05:13 PM. Reason: added PS
Active Enthusiast
Joined: Jan 2007
Posts: 102
From: Kansas City, MO
Re: Fuel Injector Shut-Off
the only time this happens is when the battery will not accept energy to be stored at a given rate because of its condition. My battery could be cold, warm or hot and the battery could be very low to full when this happens. As Rick stated, sometimes it's very hard to get a run-up.
Rick has claimed he maintained 0.0L/100km after he shifted to "N" at 50mph, and I think we all agree that either the gauge didn't pick up on fuel change, or we have feature where the battery is holding the idle.
Rick has claimed he maintained 0.0L/100km after he shifted to "N" at 50mph, and I think we all agree that either the gauge didn't pick up on fuel change, or we have feature where the battery is holding the idle.
I'm not sure we can conclude anything from the one time in N. It should be repeatable. If I can get consistent results, or if I go to N and it does NOT maintain 0.0L/100km a few times, I'll let everyone know.
-- Rick
Last edited by rmcmast; Apr 17, 2007 at 09:58 PM.
