Cruise Control Issue

TundraSoul · #1 (**permalink**) 11-19-2006, 01:43 PM

While driving up and down a mountain at 70 mph, the cruise control failed when traveling down the mountain. The decline had a 5% grade, and I found myself going 80 instead of the set speed of 70. I'm wondering if the Camry Hybrid doesn't control the speed properly on declines?

Tundrav8yamaha · #2 (**permalink**) 11-19-2006, 01:49 PM

Quote:

Originally Posted by TundraSoul

While driving up and down a mountain at 70 mph, the cruise control failed when traveling down the mountain. The decline had a 5% grade, and I found myself going 80 instead of the set speed of 70. I'm wondering if the Camry Hybrid doesn't control the speed properly on declines?

when you set the Cruise Control prior to going downhill what speed were you at if i may ask

I've never been too fond on the programming on the Cruise Control unit's on the Toyota because they often Lack refinement on programming take for example my old 00 Tundra when going up a hill The truck wouldn't maintain the speed and often at times It would jump the Gun on speeding up vs keeping a stable consistent speed. Im not sure what the problem is on your Camry But I would take that in your dealership and start asking questions about that because that doesnt seem right..

schmidtj · #3 (**permalink**) 11-19-2006, 04:41 PM

Quote:

Originally Posted by TundraSoul

While driving up and down a mountain at 70 mph, the cruise control failed when traveling down the mountain. The decline had a 5% grade, and I found myself going 80 instead of the set speed of 70. I'm wondering if the Camry Hybrid doesn't control the speed properly on declines?

If you disengaged the cruise control and just coasted down the hill the TCH will accelerate due to little to no engine braking and insufficient regenerative braking. My Prius would decellerate at 1 mph per second like clockwork but the TCH just accelerates an even modest declines. Since the crusie control does NOT control the braking I think what you are experiencing is typical for the TCH.

ToyzOnly · #4 (**permalink**) 11-20-2006, 12:15 AM

I've always heard that "cruise control" is designed for flat, level roads.
But, it's all hear-say at this point.
I've asked about this before, and was told by SEVERAL people, cruise control is NOT designed for inclines or declines.
Makes sense to me.
NO OFFENSE INTENDED!!!!!
But what the heck do I know????

TundraSoul · #5 (**permalink**) 11-20-2006, 12:32 PM

It's really strange since the cruise control does a wonderful job on heavy inclines by applying engine power as needed. You never feel the transmission down shift or anything normally felt from regular cars. I find it odd that the cruise control doesn't control heavy declines.

ToyzOnly · #6 (**permalink**) 11-20-2006, 09:18 PM

Quote:

Originally Posted by TundraSoul

It's really strange since the cruise control does a wonderful job on heavy inclines by applying engine power as needed. You never feel the transmission down shift or anything normally felt from regular cars. I find it odd that the cruise control doesn't control heavy declines.

VERY interesting...
When I tested my CC, I was on a 9% incline, and the tranny downshifted
3/4 of the way up, and I felt it.
The next time, up the same incline, with NO CC , the tranny downshifted, as expected.
A 9% incline is NO joke.
I've never paid attention to the CC when on a decline BUT, I will now.
Wanna trade tranny's???

pacific85 · #7 (**permalink**) 11-21-2006, 01:19 PM

The Camry Hybrid has the eCVT transmission, so there's not going to be a "downshift". There is a B position on the shift lever which is supposed to apply more engine braking than D provides. However, the car coasts so well, that even with B, you're going to need to use your brake pedal to control your downhill speed.

The cruise control will only control the throttle position to maintain speed. On vehicles with geared transmissions, pulling hard enough on the throttle will downshift the transmission. But on the Hybrid Camry, there's no gearing to downshift. The computer will allow the motor-generator to capture torque to regenerate electricity, but that's the extent of engine braking under cruise control. The cruise control will not engage your brake pads to slow down the car.

A light foot on the brake will engage regenerative braking. However, once the batteries are full, you'll only be wasting the regenerated energy. I don't know what the charging circuit does at that point, but I'll bet that the energy is wasted as heat somewhere under the hood, or the brake pads make contact and scrub away your speed (and generate friction which is dissipated as heat). Press harder on the brake pedal, and you eventually apply the (friction) brakes.

I learned last weekend that the B position will also disengage your cruise control. So, you can't cruise in the transmission's B position.