Steep Hills and Stop Lights

[revelated]

So,

 

Someone had the brilliant idea of having these extremely steep hills with a stop light right at the peak, all over downtown Seattle. They're annoying. They remind me why I refuse to buy a stick despite being able to drive one.

 

The other day, I was navigating around some bad traffic and ended up on one. I noticed the Fusion likes to roll back; it doesn't seem to have any hill assist. Annoying, but fine. But then when the light changed and the car ahead of me went, I pressed the accelerator...and nothing. It was like the car had stalled, despite the console and dashboard showing in a full run state. I pressed the accelerator at least two or three times, down to the floor even, and it wouldn't go. Light cycled.

 

Now, at this point I was low on the battery and the gas engine didn't kick in. So I cranked the heat thinking I could "force" the car to turn the gas engine on. Nothing.

 

Second green light, it finally went after holding the accelerator down for 2-3 seconds. Has been fine ever since. But I haven't been on that type of a hill situation.

 

Has anyone else been in that kind of situation?

[darrelld]

According to page 172 of the pdf owners manual.

 

HILL START ASSIST
WARNINGS
The system does not replace the
parking brake. When you leave your
vehicle, always apply the parking
brake and put the transmission in park (P).
WARNINGS
You must remain in your vehicle once
you have activated the system.
During all times, you are responsible
for controlling your vehicle,
supervising the system and
intervening, if required.
If the engine is revved excessively, or
if a malfunction is detected, the
system will be deactivated.
The system makes it easier to pull away
when your vehicle is on a slope without the
need to use the parking brake.
When the system is active, your vehicle will
remain stationary on the slope for two to
three seconds after you release the brake
pedal. This allows you time to move your
foot from the brake to the accelerator
pedal. The brakes are released
automatically once the engine has
developed sufficient drive to prevent your
vehicle from rolling down the slope. This
is an advantage when pulling away on a
slope, (for example from a car park ramp,
traffic lights or when reversing uphill into
a parking space).
The system will activate automatically on
any slope that will cause significant vehicle
rollback.

 

Using Hill Start Assist
1. Press the brake pedal to bring your
vehicle to a complete standstill. Keep
the brake pedal pressed.
2. If the sensors detect that your vehicle
is on a slope, the system will activate
automatically.
3. When you remove your foot from the
brake pedal, your vehicle will remain
on the slope without rolling away for
about two or three seconds. This hold
time will automatically be extended if
you are in the process of driving off.

 

 

You will want to report this to your dealer if its not working.

Edited September 13, 2014 by darrelld

[mwr]

Does that mean that if you're stopped on a steep hill (lots of those here), the car won't immediately start moving forward when you press the accelerator and remove your foot from the brake? That instead, the car will just sit there for a few seconds before it starts moving?

[darrelld]

Does that mean that if you're stopped on a steep hill (lots of those here), the car won't immediately start moving forward when you press the accelerator and remove your foot from the brake? That instead, the car will just sit there for a few seconds before it starts moving?

 

Correct, the same would happen to any gas car with hill assist if you did not apply enough energy to overcome the vehicular masses tendency to equalize the energy you expended to reach the top of hill.

[mwr]

I don't know about hill assist, but I do know that when stopped on a steep San Francisco hill, foot on the brake, it I press on the accelerator and release the brake my car (or any other "normal" car) will move forward immediately. I find it very troubling to think that the FFH couldn't do that, but instead would just sit there for a few seconds before starting forward.

[Easy Rider]

Does that mean that if you're stopped on a steep hill (lots of those here), the car won't immediately start moving forward when you press the accelerator and remove your foot from the brake? That instead, the car will just sit there for a few seconds before it starts moving?

NO that's is not correct.

If it is working properly....ALL it does is hold the brakes on after you remove your foot from the pedal for a few seconds and should release seamlessly as you apply throttle.

Now I suppose it's possible that a hill could be too extreme for it to work at all but the situation described by the OP sounds like an outright failure of something.

[hybridbear]

NO that's is not correct.

If it is working properly....ALL it does is hold the brakes on after you remove your foot from the pedal for a few seconds and should release seamlessly as you apply throttle.

Now I suppose it's possible that a hill could be too extreme for it to work at all but the situation described by the OP sounds like an outright failure of something.

Actually it doesn't apply the brakes. Your Prius applies the brakes and then releases them when you step on the accelerator. The Fusion uses the electric motor to hold the car from rolling backward. This would cause the HVB to be depleted if you aren't holding your foot on the brake.

 

The Fusion should never roll back on a hill.

[Easy Rider]

The Fusion uses the electric motor to hold the car from rolling backward.

This would cause the HVB to be depleted if you aren't holding your foot on the brake.

 

The Fusion should never roll back on a hill.

I was just reading my book today.

It clearly states that the "brake hold" only lasts a few seconds and implies that it is the actual brakes at work.

The electric motor only holds the car on a hill if you accomplish that with the accelerator pedal instead of the brake pedal.

 

So.....unless you know something that the rest of us don't and your car works differently than mine, the car will roll backwards on a steep hill IF your foot is not on either pedal AND it is not in park.

[Griswald]

Wait...if this is an automatic feature, then what is the switch on the gear selector for? Since I live in the flatlands of NC, I have not used or activated that feature.

[corncobs]

Wait...if this is an automatic feature, then what is the switch on the gear selector for? Since I live in the flatlands of NC, I have not used or activated that feature.

This is the downhill feature.

 

It allows for higher "resistance" on the regen system and helps slow down the car when driving downhill. It works very well when cruise control is active and will not pick up speed as long you don't have 100% SOC on the HVB.

[djminfll]

Living in South Florida, I have never needed to use either the Hill Assist or the downhill feature. The highest elevation I drive on is an overpass!

[revelated]

Thanks to all for the replies.

 

Re: the owner's manual snippet: Looking at the following PDF I find what you reference. But it says "IF EQUIPPED".

 

http://www.fordservicecontent.com/Ford_Content/catalog/owner_guides/13fhyom1e.pdf

 

That seems to indicate that it may or may not be on the vehicle; that it's not a standard feature. Unfortunately I find no setting in the menu nor do I find anything that tells me it does have it equipped. So the question is, if my car behaves like it's not equipped with this feature (and it's a Titanium, so I'll be rather annoyed if it isn't), how do I know for certain?

[airbusguy]

A lot of "typos" in the manuals as they have been modified from gas powered versions only. Electric motors do not like to be stalled ( brakes on) with full power apllied. The system is designed for one foot driving to avoid pressing accelerator while service brakes are still applied. If hill hold doesn't appear to work when used as per the manual - one foot brake and then transfer to accelerator- then it's a dealer visit.

[SteveB_TX]

Thanks to all for the replies.

 

Re: the owner's manual snippet: Looking at the following PDF I find what you reference. But it says "IF EQUIPPED".

 

http://www.fordservicecontent.com/Ford_Content/catalog/owner_guides/13fhyom1e.pdf

 

That seems to indicate that it may or may not be on the vehicle; that it's not a standard feature. Unfortunately I find no setting in the menu nor do I find anything that tells me it does have it equipped. So the question is, if my car behaves like it's not equipped with this feature (and it's a Titanium, so I'll be rather annoyed if it isn't), how do I know for certain?

 

Go to the Ford ETIS Website and enter your VIN under the Vehicle Tab. The left side of the results screen will show you any outstanding field service actions (recalls, etc.), while the right side of the screen shows a complete breakdown of all equipment and options installed on your car.

[Easy Rider]

This is the downhill feature.

 

It allows for higher "resistance" on the regen system and helps slow down the car when driving downhill. It works very well when cruise control is active and will not pick up speed as long you don't have 100% SOC on the HVB.

I had an opportunity to test the "downhill" feature again last week in the mountains.

It works well even after the HVB batter is fully charged......BUT the engine gets REALLY noisy.

The book says that is normal; same as manually shifting down a gear or two with a "real" transmission.

 

It won't do much after the HVB is charged if you are NOT in cruise though.

[hybridbear]

I was just reading my book today.

It clearly states that the "brake hold" only lasts a few seconds and implies that it is the actual brakes at work.

The electric motor only holds the car on a hill if you accomplish that with the accelerator pedal instead of the brake pedal.

 

So.....unless you know something that the rest of us don't and your car works differently than mine, the car will roll backwards on a steep hill IF your foot is not on either pedal AND it is not in park.

The information in the hybrid owner's manual is copied and pasted from the gas owner's manual. It is incorrect. I have verified by observing what happens using my tablet & Torque Pro that when you stop on a hill and take your foot off the brake the car discharges the HVB and sends power to the traction motor equal to the gravitational force you need to overcome to stay stationary on the hill.

[darrelld]

The information in the hybrid owner's manual is copied and pasted from the gas owner's manual. It is incorrect. I have verified by observing what happens using my tablet & Torque Pro that when you stop on a hill and take your foot off the brake the car discharges the HVB and sends power to the traction motor equal to the gravitational force you need to overcome to stay stationary on the hill.

 

This makes sense so the counter rotational forces of the incline are overcome quicker by prestaging a proportional amount of inverter current to the traction motor.

Edited September 14, 2014 by darrelld

[Easy Rider]

The information in the hybrid owner's manual is copied and pasted from the gas owner's manual. It is incorrect. I have verified by observing what happens using my tablet & Torque Pro that when you stop on a hill and take your foot off the brake the car discharges the HVB and sends power to the traction motor equal to the gravitational force you need to overcome to stay stationary on the hill.

OK so is the part about it only lasting a few seconds also wrong ??

I would do a test but don't have any hills big enough close by.

Will be going over the Smokies again next week; will test if I remember.

[aschulz261]

I just tired this with mine. Stopped on a step hill. Let off the brake and the car held for about 2 seconds, then slowly started rolling backward. It would appear that the amount of torque applied to the motor at "idle" can be overcome by a steep enough hill.

 

While stopped on the hill, releasing the brake and accelerating before the 2 seconds are up, the car just drives off like a normal car would do.

[gkinla]

I just tired this with mine. Stopped on a step hill. Let off the brake and the car held for about 2 seconds, then slowly started rolling backward. It would appear that the amount of torque applied to the motor at "idle" can be overcome by a steep enough hill.

 

While stopped on the hill, releasing the brake and accelerating before the 2 seconds are up, the car just drives off like a normal car would do.

 

 

I just tried the hill assist in the dark, on a pretty steep hill watching the reflection of my stop lights in the rear view mirror. When the hill assist is engaged the stop lights are on for two seconds, then when the hill assist is released the stop lights turn off. This is with my foot off the brake pedal. If the brake light switch is hydraulically activated then it's on with the brakes applied. I don't think it's mechanical because my foot is off the brake pedal and the brake lights stay on. With the car dead quiet , no air, no radio, no ICE, you can hear something release. IMHO I think the brakes stay applied, held, then released in two seconds.

 

For 50 years, I've always applied the brakes with my left foot. I've never had a car roll back on me because my left foot is the hill assist. And no, I don't ride the brakes because I use my left foot for braking, my foot is off the pedal until I need the brakes. The hill assist is a great convenience for those of you that brake and accelerate with the right foot only. I drive a stick occasionally and never get confused with the clutch pedal and using my right foot for braking. When driving a stick shift, most often it has a center console parking brake, then this becomes the hill assist. I set the brake and release it when the clutch starts to grab. With an automatic transmission, I always thought it was more efficient using left foot for braking and right foot for gas.

[GrySql]

 

With an automatic transmission, I always thought it was more efficient using left foot for braking and right foot for gas.

My wife does the same, makes me nervous to watch but she's a good driver. There were not many automatic transmissions when we learned to drive.

Edited September 15, 2014 by GrySql

[hybridbear]

I could be wrong. I will need to find a hill and test it out. There aren't many hills around here.

[Waldo]

From the shop manual:

 

Hill Start Assist

When the vehicle is stopped on an incline the ABS module holds the brake pressure for approximately 1.5 seconds while the driver transitions from the brake pedal to the accelerator pedal. This is accomplished by monitoring several HS-CAN messages and several sensors to determine if the vehicle is stopped and not parked, and if the vehicle is on an appropriate incline. The brake pedal message sent by the PCM and the wheel speed sensor inputs allow the ABS module to determine the vehicle has come to a complete stop. The transmission selector lever message sent by the PCM informs the ABS module the vehicle is not parked. The stability sensor messages sent by the RCM enable the ABS module to determine if the vehicle is on an incline greater than 1.5 degrees (approximately a 3% grade). Once the above conditions have been met, the hill start assist function automatically engages. As the driver releases the brake pedal, the ABS module commands the HCU to close the isolation valves which maintain the current brake system pressure, preventing the vehicle from rolling down the incline. Once the driver presses the accelerator pedal and the torque produced by the engine reaches a specific level, the ABS module gradually releases the brake pressure to make sure the vehicle is neither rolling back nor driving off until there is sufficient driving torque to move the vehicle forward (or backward if reversing up the incline). For vehicles with an automatic transmission the incline must be greater than 3.5 degrees (approximately a 6% grade), for vehicles with a manual transmission the incline must be greater than 1.5 degrees (approximately a 3% grade) and for vehicles equipped with the stop/start feature (regardless of transmission) the incline must be greater than 0.5 degrees (approximately a 1% grade).

[gkinla]

From the shop manual:

 

Hill Start Assist

 

 

 

Thanks Waldo, you've confirmed my, seat of the pants analysis.

[revelated]

Thanks again for the replies.

 

My home has hills but nowhere near as steep as downtown Seattle. I was trying to find one of those streets so I could Street View and show you guys but the street system is so illogical. The only way I even found it was nav taking me there randomly.

 

I can assure you that the grade was extreme. I'm going to guess 60-70 degree, if you can picture that.

 

I wonder if there is some "timeout". So for example you're sitting there with the brakes applied but because there's a red light at the peak you're there 2-3 minutes before you can go. If the Hill Assist assumes you'd be applying brakes no longer than a few seconds to a minute, that would explain what I experienced. But that'd be a huge issue. And in any event it doesn't explain why the car wouldn't accelerate immediately.

 

I have no way to replicate it for the shop because there are no super-steep Hills around. Sigh