Slight hum or whine at steady speed in ICE

[DonE37]

FFH owner here for the last two months and a glorious 4,000 miles so far! Huge car nut and enthusiast. I am loving this car, but I have one issue with it that I haven't found much about online or on forum posts. The following is one forum post I did find that describes the problem and my following comment:

 

Posted by: Akeel Zaheer | Aug 3, 2009 2:41:09 PM

 

Bought a Ford Fusion Hybrid about three weeks ago. Have about 600 miles on it. Love it so far. Getting great mileage - avg 40mpg. Some trips I get 46 mpg if it is highway and city blend.

 

One issue that I want other owners to comment on is a faint but distinct hum/whine when accelerating through or holding steady at speeds between 40-45 mph, Anyone experience this? Any thoughts on why this could be happening.

 

appreciate any thoughts/comments.

 

Posted by: Don | Sep 25, 2009 4:59:57 PM

 

Akeel, it is amazing you mention that about the slight whine. I have the very same noise. It is not loud and happens at same time you explained. I was seaching on the internet with keywords "whine and "Fusion hybrid" and came up with this forum post. I can't find anything else however. It is good that at least I know somebody else hears the whine because my wife thinks I am being anal.

 

Other than that, my Fusion Hybrid is awesome. And that is coming from a car enthusiast that owns way to many cars!

 

Let me elaborate a little more. Sound is prevalent at steady speed with ICE, and when you step off the throttle to go into EV the sound dissipates, almost sounds as if its getting choked off, like suction thru a tube slowly being closed off. wondering if it is air intake reverberation , and it also dissipates when you are in ICE and push more on the throttle. The sound to me seems to be getting louder as I put on the miles. Starting to here it at speed around 60 with slight throttle application. Usually the stereo is fairly low or off in the car.

 

Any comments would be much appreciated!

 

Don

[Oman]

Most of the whine in a full hybrid comes from MG1 which is the electric motor than acts as an rpm/torque converter and is essentially the transmission and ICE starter. MG2 is the traction motor and can be heard mainly in EV mode when it is being used for recovery braking. It makes more of a low pitched noise that can be slightly felt through the chassis of the car.

 

The whine of MG1 is not directly tied to speed, rather it will make noise as a combination of current ICE RPM and wheel speed. The RPMs of MG1 are highest around 45-55MPG when there is no or little ICE demand. It makes the most noise when it is spinning the fastest and/or working the hardest.

 

Electric motors whine when they work and there are two of them in the car always working - even when not in EV mode. They actually work the hardest when you stomp on the throttle but you can't hear them over the ICE.

 

When there is high power demand the ICE RPMs will be high but the vehicle speed won't be as high. MG1 drops the RPMs out of the ICE and converts them to torque by generating electric power. MG2 then uses this power (along with any spare battery) to assist the ICE.

 

When some of the FFHs are new the whining is loud enough for people in the car to think there is a far-off police car somewhere. As the car goes through the first 10K miles the sounds settle down a bit but they will always be there.

 

Pretty much everyone who isn't always cranking the stereo notices the difference in sounds between the hybrid and an ICE only car. I'm more surprised that people don't ask about the lack of shifting/gear changes in the car.

 

Jon

 

 

FFH owner here for the last two months and a glorious 4,000 miles so far! Huge car nut and enthusiast. I am loving this car, but I have one issue with it that I haven't found much about online or on forum posts. The following is one forum post I did find that describes the problem and my following comment:

 

Posted by: Akeel Zaheer | Aug 3, 2009 2:41:09 PM

 

Bought a Ford Fusion Hybrid about three weeks ago. Have about 600 miles on it. Love it so far. Getting great mileage - avg 40mpg. Some trips I get 46 mpg if it is highway and city blend.

 

One issue that I want other owners to comment on is a faint but distinct hum/whine when accelerating through or holding steady at speeds between 40-45 mph, Anyone experience this? Any thoughts on why this could be happening.

 

appreciate any thoughts/comments.

 

Posted by: Don | Sep 25, 2009 4:59:57 PM

 

Akeel, it is amazing you mention that about the slight whine. I have the very same noise. It is not loud and happens at same time you explained. I was seaching on the internet with keywords "whine and "Fusion hybrid" and came up with this forum post. I can't find anything else however. It is good that at least I know somebody else hears the whine because my wife thinks I am being anal.

 

Other than that, my Fusion Hybrid is awesome. And that is coming from a car enthusiast that owns way to many cars!

 

Let me elaborate a little more. Sound is prevalent at steady speed with ICE, and when you step off the throttle to go into EV the sound dissipates, almost sounds as if its getting choked off, like suction thru a tube slowly being closed off. wondering if it is air intake reverberation , and it also dissipates when you are in ICE and push more on the throttle. The sound to me seems to be getting louder as I put on the miles. Starting to here it at speed around 60 with slight throttle application. Usually the stereo is fairly low or off in the car.

 

Any comments would be much appreciated!

 

Don

[DonE37]

Thank you Jon for a very comprehensive answer to my question. The electric motor whine does seem like the probable cause for the noise. However, I may have mislead you with it just being an electric motor whine noise. I do actually here the wonderful electric motors and delight in the sound idiosynchrosis of a hybrid vehicle. This sound is more related to the ICE part of motivation. One example of the sound it makes could be confused as wind screen noise, or whistling thru a tube. And is directly related to ICE intervention. You could say, it is less of an EV whine and more of a whistle. Another example: Turn on your vacumm cleaner and slowly put your hand over the suction part of the tube. It will make a whistling noise, pitch rising as your hand gets closer to closing off the tube and then a faint pop and an abrupt silence as your hand gets suctioned on to the tube. This is the sound that is heard when the ICE shuts off. That is why I had mentioned maybe air intake noise of some kind.

 

It could also be like you said, MG1 shutting down just as the ICE shuts down and I am confusing it for ICE. Maybe I will take an FFH for a test drive at the local ford dealer and see if I can replicate it. Or if anybody else has an example of this noise it would be much appreciated.

 

Thanks again Jon for your response.

 

Don

[Oman]

A good test would be to put the display into the mode that shows the ICE RPM. Then accelerate through several speeds using different amounts of throttle. This was an interesting exorcise for me as it is amazing how large of an RPM range the ICE will go depending on demand for the same vehicle speed. On my car I can make a distinct whine right around 60MPH at about 25% throttle. If you get it at certain combinations of ICE RPM and vehicle speed then it is MG1. If you only get it at certain ICE RPMs then it is likely some aspect of the ICE itself. On my vehicle I have noticed several different sorts of motor whine but only a single "engine" sound from the ICE that is directly related to ICE RPM and amount of throttle.

 

Jon

 

 

Thank you Jon for a very comprehensive answer to my question. The electric motor whine does seem like the probable cause for the noise. However, I may have mislead you with it just being an electric motor whine noise. I do actually here the wonderful electric motors and delight in the sound idiosynchrosis of a hybrid vehicle. This sound is more related to the ICE part of motivation. One example of the sound it makes could be confused as wind screen noise, or whistling thru a tube. And is directly related to ICE intervention. You could say, it is less of an EV whine and more of a whistle. Another example: Turn on your vacumm cleaner and slowly put your hand over the suction part of the tube. It will make a whistling noise, pitch rising as your hand gets closer to closing off the tube and then a faint pop and an abrupt silence as your hand gets suctioned on to the tube. This is the sound that is heard when the ICE shuts off. That is why I had mentioned maybe air intake noise of some kind.

 

It could also be like you said, MG1 shutting down just as the ICE shuts down and I am confusing it for ICE. Maybe I will take an FFH for a test drive at the local ford dealer and see if I can replicate it. Or if anybody else has an example of this noise it would be much appreciated.

 

Thanks again Jon for your response.

 

Don