Cyclical Engine Noise

I have no clue, but I'm leaning to the idea your hearing the car do it's normal thing, and you should be fine.

 

I drive in that speed range everyday on my daily commute. If you will watch the Energy Monitor screen that shows the red arrows indicating ICE power flow to the wheels and then the white electrical flows between the HV battery, the MG's and the wheels, you will notice at around 60 mph it appears at times where the only power flow is from the ICE to the wheels with no electrical flow. Then depending on the terrain and any slow rolling hills that the electrical flow will seem to switch back and forth from the wheels and then to the battery. I have always thought of this as the speed where the ICE can maintain its "sweet spot" with little or no help from the electric motors. Maybe the experts can chime in and give a more technical explanation for this.

I think what you are hearing is the balancing act between the ICE and the electrical power flow between batteries and MG's. This is completely normal and what the computers do to maintain peak efficiencies.

 

Well, I think it is going to take an awful lot more diagnostics if you really want to figure out what is going on. However, it is not likely there is a real problem. Does it happen only when you are trying to maintain constant speed? Does it happen when you are accelerating through this region? How hard are you accelerating? If it is on a flat road at constant speed, you are going to be pretty close to the center line on the HSI to maintain 55 at which point you may be hearing the ICE kick on and off. The minimum ICE output at the center line of the HSI is about 10 kW, slightly above that and the car will accelerate at 55. The ICE always be running at 65 if you are very careful at keeping power (HSI about 20% above the center line) as this requires about 15 kW and you won't hear it powering on and off. Above ~47 MPH the ICE spins at 1000 RPMs and is unfueled even if you are gliding. However, when the ECU decides you want ICE torque it begins to add fuel. You can hear a slight rumble over the road noise and feel a slight jolt when this happens. It is possible this is what you are experiencing.

Of course it could be something else entirely. The car makes lots of quiet, funny little noises as it is running one or another subsystem. Those 26 "computers" the technician was telling you about report something like 1000 parameters on the car's networks. It is probably possible to figure out your noise by looking at these, but it is probably also not worth the effort. The technician is also correct in that the car is pretty good at monitoring itself for signals that are out of limits and that indicate a real problem. I would either spend a lot more effort to try to figure it out, try to ignore it, or always drive over 65 (or under 55).

 

My 2010 Prius ll upon accelerating moderately sounds like...remember having an older V8 with a 4 barrel carb, and how it would react when all four barrels would open upon mashing down on the gas pedal you would get that loud suction sound. I would hope that that is normal. Is it?
Thanks,
Joe B