2007 Camry Hybrid Cruise Control Operation?

[paulfweeks]

Curious how the cruise control works in the hybrid version:

When going downhill (and cruise is set to a speed [ie like 60]);
Does it just exceed the set speed (as it would in a regular gas engine) or does it engage "dynamic braking" to charge the hybrid battery?

When in hilly country and going uphill (and cruise is set to a speed[ie like 60]);
Does it downshift the transmission (as it would in a regular gas engine) or does it engage the hybrid (electric) motor?

Thanks for the info.

[schmidtj]

I can't speak the the Camry but since it uses the Hybrid Synergy Drive as does the Prius (which I own one) here is what I've seen:

In cruise you don't accelerate downhill when in cruise and the power management screen shows the battery being charged.
On an aside if I am NOT in crusise and coasting down a moderate hill the car still deccellerates exactly the same way as when coasting on level terrain. It's as if it's programmed to decellerate (probably through regenerative braking) when not maintaining speed or accelerating.

My understanding is there is a maximum RPM the electric traction motors can not exceed. The more Internal Combustion Engine (ICE) RPMs the fewer traction motor RPMs. So when on electric assist or braking at higher speeds the ICE can actually be rotating even though it's not consuming fuel. The HSD does this to keep the electric motor from overspeeding.

Yes when going up a hill on cruise the engine RPM increases. Since the thansmission is a Continiously Variable one there are no real shiftpoints but the ICE does vary in RPM depending on the speed and load.

Hope this helps.

J

[paulfweeks]

Appreciate your info re: how the "cruise control" operates in a Prius.

Suspect that the Camry operates similarly except: Since the 5 speed auto trans. has specific gear ratios {ie. when going uphill in cruise (~~ 2000RPM = 60 mph in 5th gear) }that the traction drive (electric motor) kicks in to add horsepower [if required to maintain set cruise speed]. If the speed still drops off with the traction drive engaged it then downshifts the trans to maintain set cruise speed.

Have looked at the info (including the flow diagrams) on this website showing how the trans operates but it didn't describe how this function operated.


Maybe somebody who has a 2007 Camry Hybrid can check in with more detail info.

Thanks again

[spiff72]

Originally Posted by paulfweeks

Suspect that the Camry operates similarly except: Since the 5 speed auto trans. has specific gear ratios ...

Are you referring to the Prius having the 5-speed auto tranny? Or the Camry? I ask, since the Camry Hybrid uses a continuously variable transmission, not a 5-speed.

[mustang67408]

Does this help? Or do you have this already.

[paulfweeks]

Thanks for the info. The point I was missing is that the Camry Hybrid has the "continuously variable" transmission. I assumed (mistakenly) that it had the 5 speed auto as in the regular Camry! I had looked at the "cruise control" pdf but somehow missed the point about the CV transmission.

Thanks,