(dumb) idea: "Kinda-Conserve" Mode?

[mikehmb]

Unfortunately, I don't know specifics either - all I know is that in my experience with gen 1 quad, the disconnect is fairly abrupt and rough (thus the need for a separate drive mode to choose whether it's connected or not). On dual and gen 2 tri/quad, the disconnect is much faster and smoother to make it nearly imperceptible. (Except for the most recent update on dual motor, but that's a software issue covered on another thread). That's why the newer system has an automatic disconnect, rather than the manual disconnect selected via drive mode

Early-ish on for the quads, they put in a SW fix that derated the motor temporarily while the disconnect/reconnect was happening. Not sure if you had your truck prior to that, but the disconnect/reconnect used to be very abrupt and clunky.

It's still noticeable, but thankfully doesn't make a horrible noise. It was spooky enough that I'd deliberately lift off accel a bit to reduce coupling stress while it was taking place, or just do it from a full stop. Didn't like that noise.

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[mpshizzle]

Early-ish on for the quads, they put in a SW fix that derated the motor temporarily while the disconnect/reconnect was happening. Not sure if you had your truck prior to that, but the disconnect/reconnect used to be very abrupt and clunky.

It's still noticeable, but thankfully doesn't make a horrible noise. It was spooky enough that I'd deliberately lift off accel a bit to reduce coupling stress while it was taking place, or just do it from a full stop. Didn't like that noise.

I only say this from more recent experience with gen 1 loaners (and my friend's truck). It scared me a few times. I can only imagine what it was like before the software update

 

[CANCERDOC]

The front tire wear in the G1 Quad conserve is due to it being FWD all the time, and wears most when you initially accelerate from a stop. In the Dual AP or Tri conserve, its always AWD when you first start off, which prevents all the tire wear on the front. I think its a reasonable compromise to keep the front tires from wearing down too quickly.

 

[Donald Stanfield]

Oh I was referring to Gen 1, which is magnetic disconnect as well but may not be the same mechanism exactly.

The Munroe teardown went into some good detail on it, but it's been a while since I've watched it.

Unsure how the Tri or Gen2 Quad rear clutches work, nor do I understand how the dual rear disconnect operates.

EDIT - thanks @MountainBikeDude for the link and bookmark:

The Gen 1 uses a a dog clutch with those little metal toggle tabs which is externalized from the drive units (and there are by definition two of them), while the DUAL rear unit uses an integrated clutch which is still magnetically actuated, but not a dog clutch (it's a simpler and probably more reliable gear mating system).

This still doesn't answer the Tri-Motor clutch question. If they are using in-house units in the rear (x2) and have done the integration with the new clutch assembly, it should be able to auto-disengage.

BUT - if they are using units similar to gen1 with the dog clutch, then they are still stuck with semi-manual disconnect.

Anyway - this has been an area of interest for me for some time, and I hope to see a Tri-motor rear (or G2 quad) teardown at some point.

The tri-motor has the ability to auto engage the rear motors so I assume it has the same system as the dual motors. On my old quad when I went into conserve the power bar had hashes through it on the top end indicating that motor power is limited because the rear motors are physically disconnected. On my new trimax the hashes are not there on the power bar and I have maxed out the power bar while passing which seems as fast as it does in AP mode while passing.

My understanding is the tri has all three motors engaged all the time unless in conserve, and in conserve it can engage the two motors in back if the demand for acceleration is there.

 

[mikehmb]

The tri-motor has the ability to auto engage the rear motors so I assume it has the same system as the dual motors. On my old quad when I went into conserve the power bar had hashes through it on the top end indicating that motor power is limited because the rear motors are physically disconnected. On my new trimax the hashes are not there on the power bar and I have maxed out the power bar while passing which seems as fast as it does in AP mode while passing.

My understanding is the tri has all three motors engaged all the time unless in conserve, and in conserve it can engage the two motors in back if the demand for acceleration is there.

Very interesting.

Using the butt-dyno, does that hold up? Meaning, accel test in Auto mode, followed by accel test in Conserve, and you get similar results as measured by the seat of one's proverbial pants? (not to suggest that there's some f*ckery going on in the UI by masking the lack of available power, but wouldn't be surprised)

 

[ElGuano]

My understanding is the tri has all three motors engaged all the time unless in conserve, and in conserve it can engage the two motors in back if the demand for acceleration is there.

Agreed, and in my informal observations, the back motors only come on line if there is a fairly aggressive demand for power (like, if you need to pass someone on the freeway). However, it's optimized to prefer front-wheel-drive in any other situation, including when you accelerate gently at a green light.

Question for the dual-motor folks - if you drive conservatively in AP mode, is it the case that you can ALWAYS be in front wheel/one-motor mode? Or are there cases where it's AWD all the time no matter how light you are on the pedal?

 

[Donald Stanfield]

Very interesting.

Using the butt-dyno, does that hold up? Meaning, accel test in Auto mode, followed by accel test in Conserve, and you get similar results as measured by the seat of one's proverbial pants? (not to suggest that there's some f*ckery going on in the UI by masking the lack of available power, but wouldn't be surprised)

I'd say it holds up. I remember in my gen 1 quad in conserve on the freeway I would bump up against it's more limited passing power on occasion. In conserve on the trimax I haven't ran into that issue at all and it feels to me to be the same amount of power as AP. Not the same as sport mode, but I don't need that feel to pass on the freeway, AP is more than enough to dust the sort of idiots you find yourself needing to pass quickly.

If it does engage the rear motors there's no reason to believe the power delivery would be any different, and we know for certain this is how AP mode operates in the dual vehicles so to me it matches up. With that said this is only observational I cannot be certain.

 

[Donald Stanfield]

Agreed, and in my informal observations, the back motors only come on line if there is a fairly aggressive demand for power (like, if you need to pass someone on the freeway). However, it's optimized to prefer front-wheel-drive in any other situation, including when you accelerate gently at a green light.

This coincides with my experience perfectly. You need to go from zero to half or more throttle, as in an immediate passing sort of scenario, to feel the truck kick on the rear motors.

 

[mpshizzle]

Agreed, and in my informal observations, the back motors only come on line if there is a fairly aggressive demand for power (like, if you need to pass someone on the freeway). However, it's optimized to prefer front-wheel-drive in any other situation, including when you accelerate gently at a green light.

Question for the dual-motor folks - if you drive conservatively in AP mode, is it the case that you can ALWAYS be in front wheel/one-motor mode? Or are there cases where it's AWD all the time no matter how light you are on the pedal?

For the dual motor there is no mode that is EXCLUSIVELY FWD. You could maybe do it if you're just cruising and never apply too much throttle. But taking off from a stop will always be AWD until you hit about 20.

Afaik the only exclusively FWD mode that exists in Rivian land is G1 quad conserve

 

[CANCERDOC]

For the dual motor there is no mode that is EXCLUSIVELY FWD. You could maybe do it if you're just cruising and never apply too much throttle. But taking off from a stop will always be AWD until you hit about 20.

Afaik the only exclusively FWD mode that exists in Rivian land is G1 quad conserve

This, yes its AWD always when setting off from a stop until around 20mph. Dual motor can never accelerate FWD only from a stop.

 

[pickupman2022]

Agreed, and in my informal observations, the back motors only come on line if there is a fairly aggressive demand for power (like, if you need to pass someone on the freeway). However, it's optimized to prefer front-wheel-drive in any other situation, including when you accelerate gently at a green light.

Question for the dual-motor folks - if you drive conservatively in AP mode, is it the case that you can ALWAYS be in front wheel/one-motor mode? Or are there cases where it's AWD all the time no matter how light you are on the pedal?

Will always be AWD until around 17-20 mph, then it disconnects if you're gentle. Step on it hard/fast AWD comes back on. Slip a wheel, AWD comes back on. AWD reengages when you stop or slow way down, maybe 10 mph.

 

[portdirect]

Very interesting.

Using the butt-dyno, does that hold up? Meaning, accel test in Auto mode, followed by accel test in Conserve, and you get similar results as measured by the seat of one's proverbial pants? (not to suggest that there's some f*ckery going on in the UI by masking the lack of available power, but wouldn't be surprised)

It lags a bit on conserve until the rears have connected - ie if you stamp on the pedal it takes a moment (0.5s?) longer to 'spool up' - then its feels the same.

 

[Dark-Fx]

It is my (likely flawed) understanding that Conserve in the Tri trucks uses the same mechanical clutch as on the quads for the rear motors. I suspect it is the same motors, as the quads but have no data. Someone here should know more and hopefully can point to a video somewhere.

I don't know how Conserve works in the dual motor trucks, but it's automatic, because there isn't (AFAIK) a "Conserve" mode per se. It just ... conserves ... by disconnecting.

Anyone have detail how the rear motor disconnect works (electro-mechanically speaking) in the Duals?

Tri is using a gen3 motor in the rear, the geartrain looks a lot like the enduro, just doubled. It doesn't have the gen1 style actuators attached to the outside of the case.

 

[jaredm]

OP - you don't want a auto-disengaging AP like the Duals. Probably my biggest annoyance with my DMP. I understand you want it to auto-disengage only at high speeds but I know I wouldn't. I would much rather engage Conserve mode myself. And have a fun AP mode for most of my non-road trip drives.

Though, as a DM owner, I would rather have your proposed AP solution instead of what we got. I hate how often it disconnects. Feels like a yo-yo, or the early days of CVTs that people complained feels rubberband-y. I have my foot down to accelerate, though not flooring it, and my rear motor disconnects. Meh

AP in Dual is the same as Conserve in Tri.

I don't think that's 100% true. Mechanically, yes, but I'd wager Conserve mode also tames the throttle response similar to Snow mode (but I don't know for certain).

 

[Zoidz]

I’m not a fan of automatic drive mode changes. I don’t want it deciding to change modes in rain, snow, corners, etc. potentially affecting the handling dynamics. We have enough dumbing down in America, I don’t want dumbing down in my Rivian performance.

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