2014 Ford Fusion Hybrid Electronic Emergency Break Manual Release?

[hybridbear]

Mine stays ON until I press the "gas pedal" slightly.....then releases.

This is handy since the "hill hold" feature of the brakes only lasts a few seconds.

The hill start assist in the FFH should hold for a long time. I have stopped on steep uphills at a red light and sat for over a minute with the car holding itself in place. You might be getting confused with the system in your Prius. The stupid Prius system doesn't activate automatically and only holds for a few seconds.

[Easy Rider]

You might be getting confused with the system in your Prius. The stupid Prius system doesn't activate automatically and only holds for a few seconds.

 

No.....really.......you think ?? :)

 

Yes, that's entirely possible.

Now that you mention it, I really don't remember for sure.

 

I do know that it "self releases" when you GO.....because the Prius certainly won't do that !!

[Waldo]

The hill start assist in the FFH should hold for a long time. I have stopped on steep uphills at a red light and sat for over a minute with the car holding itself in place. You might be getting confused with the system in your Prius. The stupid Prius system doesn't activate automatically and only holds for a few seconds.

 

I don't know how the system in the FFH works, but the system in every other Ford will only last for a few seconds. Does the Fusion system use electric motor torque to overcome gravity? If so, wouldn't this drain the HVB while you sat?

 

Edit, the shop manual would seem to contain the same text that's used on the non-hybrid vehicles, so I'm not sure if it's actually correct for the hybrid or not:

 

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 High Speed Controller Area Network (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).

Edited May 12, 2014 by Waldo

[acdii]

The EV portion applies enough torque to hold the car, or keep it from rolling back. It's interesting that when you remove your foot off the brake the car starts to roll forward as if an ICE is spinning a torque converter in a conventional transmission. It is probably just how it is programmed to mimic a regular car. Since it looks to move the car forward when the brake is released, it would feel like Hill Holder is applied.

[hybridbear]

The EV portion applies enough torque to hold the car, or keep it from rolling back. It's interesting that when you remove your foot off the brake the car starts to roll forward as if an ICE is spinning a torque converter in a conventional transmission. It is probably just how it is programmed to mimic a regular car. Since it looks to move the car forward when the brake is released, it would feel like Hill Holder is applied.

The hybrid does have "idle creep". On some electric cars you can turn this on & off in the settings. I like it because it allows you to crawl forward in traffic very smoothly.

 

 

I don't know how the system in the FFH works, but the system in every other Ford will only last for a few seconds. Does the Fusion system use electric motor torque to overcome gravity? If so, wouldn't this drain the HVB while you sat?

 

Edit, the shop manual would seem to contain the same text that's used on the non-hybrid vehicles, so I'm not sure if it's actually correct for the hybrid or not:

 

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 High Speed Controller Area Network (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).

The hybrid works by using the traction motor to apply the exact amount of force needed to overcome gravity. I prefer to avoid sitting at stops on hills this way because you might be pulling 5+ kW from the battery to hold the car in place rather than only the .5 kW or so that's used by the DC to DC converter to charge the 12V battery. If you keep your foot on brake then the electric motor doesn't get involved. However, it is very easy to accelerate away from a stop on a hill in the FFH because there's a perfectly smooth transition from stopped to moving, unlike in the Prius.

 

 

No.....really.......you think ?? :)

 

Yes, that's entirely possible.

Now that you mention it, I really don't remember for sure.

 

I do know that it "self releases" when you GO.....because the Prius certainly won't do that !!

I referred to the Prius system as "stupid" above because it isn't a "smart" system like in the FFH. The Prius system works by engaging the brake pads to hold you in place on the hill. Once you step on the gas the Prius will release the brake pads but it is very jerky. It will not use the electric motor to hold you in place. If you don't engage the hill start assist you will roll backward slightly when you release the brake on a hill before stepping on the gas. It is very annoying.

[acdii]

And now you know why I was so glad to get rid of the one I had! The most fun I ever had in it was trying to go up a hill in a light snow, NOT.

[OneSpeed]

I think this is a strange Park Brake system and would rather have a standard mechanical system.

What advantage is there in an all electronic Park Brake that has no way to release if you have an electronic failure?

Just seems like a bad idea to me. I can't see a thief being discurraged by this system. Seems like all they need to do is unplug the calipers then jump the wires at the calipers to release the brakes?

[Waldo]

The biggest advantage is that you don't need to use the space inside the car for a big handle or pedal. I've had plenty of experience with jammed cables and calipers, I certainly wouldn't call the mechanical systems reliable and fool-proof.