Jerking

[bill77ocean]

Hi, i have the 2010 fusion hybrid, lately been noticing, when at a light and slightly letting off the brake pedal, theres like a jerking or a small surging feel, also noticed that with slight gas pedal acceleration on a hill was same kinda jerking feeling, is this normal? it does not do it during normal driving though....been wondering if its the transmission clutch slipping a bit..was thinking about taking it in to have it serviced anyway soon, but this does seem a bit odd.

[lolder]

Hi, i have the 2010 fusion hybrid, lately been noticing, when at a light and slightly letting off the brake pedal, theres like a jerking or a small surging feel, also noticed that with slight gas pedal acceleration on a hill was same kinda jerking feeling, is this normal? it does not do it during normal driving though....been wondering if its the transmission clutch slipping a bit..was thinking about taking it in to have it serviced anyway soon, but this does seem a bit odd.

This is probably normal. There is no clutch; there is no torque converter. When you have the brake on at very low speeds or at a stop, there is no electrical power being applied to MG2, the traction motor. When you release the brake, the system applies a small amount of power to MG2 to simulate the "creep" of an automatic transmission with a torque converter . Under certain circumstances, you may notice this transition, especially if you slowly release the brake. They system does not apply any voltage to the motor when the brake is on as it would be wasteful. There is also a transition during braking at about 5 mph from regen to friction braking that can sometimes be felt.

Edited May 4, 2010 by lolder

[bill77ocean]

This is probably normal. There is no clutch; there is no torque converter. When you have the brake on at very low speeds or at a stop, there is no electrical power being applied to MG2, the traction motor. When you release the brake, the system applies a small amount of power to MG2 to simulate the "creep" of an automatic transmission with a torque converter . Under certain circumstances, you may notice this transition, especially if you slowly release the brake. They system does not apply any voltage to the motor when the brake is on as it would be wasteful. There is also a transition during braking at about 5 mph from regen to friction braking that can sometimes be felt.

Thanks for your comment on this, but like i said i also noticed this on a hill at a red light, i was giving very slight pedal acceleration, and felt the same thing with the brake pedal released..but hmmm, no clutches huh, i realize its a CVT, but thought there would be some sort of clutch on it.. but okay

Edited May 4, 2010 by bill77ocean

[lolder]

Thanks for your comment on this, but like i said i also noticed this on a hill at a red light, i was giving very slight pedal acceleration, and felt the same thing with the brake pedal released..but hmmm, no clutches huh, i realize its a CVT, but thought there would be some sort of clutch on it.. but okay

There is lots of information available about the hybrid Power Split Device (PSD) that many hybrids use. The Toyota and Ford systems are very similar differing mostly in geometry and size. They were developed separately but closely resemble each other in function for the same reason many jet passenger aircraft look alike; the best designs yield similar results. If you pursue learning about these systems, you will realize how revolutionary they are. If you are holding the brake, you can make the ICE start by pushing on the accelerator. This can cause some observable shudder. No hills around here.

[funny]

I have had my car for about 5 weeks now and have experienced a similar jerking phenomenon about 2-3 times. It is a bit unpleasant and different than the minimal sensation of the ICE transition. My initial thought was "transmission slippage" but was not too worried as the car is new.

[ralteredstates]

Ambulance chaser in a different type of suit. Just increases my respect for the profession.