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So volt is a single speed engine. What is the volt doing when I accelerate, engine noise gets higher and higher, and once I get to a steady speed, the engine noise reduces, as if I changed into a higher "gear"? What's going on there?
 

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I'm assuming you're using the colloquial use of 'speed' as in a "10 speed bike" = bike with 10 gears.

In which case, yes, the engine only has one fixed output "speed"/"gear", but it will rev at different levels as mentioned above.

In addition to running the engine harder when required, the actual manipulation of engine output vs wheel output is maintained by the electric motors, adding or removing energy as required.
This effectively makes it "infinite gears".
 

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I'm assuming you're using the colloquial use of 'speed' as in a "10 speed bike" = bike with 10 gears.

In which case, yes, the engine only has one fixed output "speed"/"gear", but it will rev at different levels as mentioned above.

In addition to running the engine harder when required, the actual manipulation of engine output vs wheel output is maintained by the electric motors, adding or removing energy as required.
This effectively makes it "infinite gears".
When you are running on the ICE at highway speeds the engine directly drives the wheels in the Gen2 Volt so obviously it's not turning at a single speed, like any ICE it's speed is directly related to the speed of the car. At lower speeds the ICE is just driving the generator and the electric motors are driving the wheels so under those circumstances the engine will turn at a constant velocity.
 

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When you are running on the ICE at highway speeds the engine directly drives the wheels in the Gen2 Volt so obviously it's not turning at a single speed, like any ICE it's speed is directly related to the speed of the car. ....
Right. The Gen1 would do this too in certain conditions.

The Volt is simply a Hybrid when the engine in running, series or parallel.
The engine RPM tracks the road speed when operating as a series hybrid.

The OP is confused.
 

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Accelerating uses more energy than cruising. That's why the engine is louder in every single car while accelerating. It has nothing to do with "speeds" or "gears".
 

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It seems like our Gen 2 Volt when on the gas engine run somewhat different since the GM software update. It seems to run harder for less time than levels off, where in the past it seems to run for a longer period of time, in any event the mpg did improve by at least 3 mpg's. Whatever the software update did, it is a much improvement, as the engine runs smoother and little or less notice when the gas engine is running and more mpg's as well..
 

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Depending on the specifics (at a stoplight, cruising a city street, on the highway) one (and maybe the only) thing it's doing is generating electricity. Depending on how depleted the battery is, it may rev more to fill the battery. At other times it may be helping drive the wheels as noted above.
 

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First wrong assumption is the engine runs at a single speed. The speed is not directly related to acceleration, but to requirements to maintain minimum battery charge.
 

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So volt is a single speed engine. What is the volt doing when I accelerate, engine noise gets higher and higher, and once I get to a steady speed, the engine noise reduces, as if I changed into a higher "gear"? What's going on there?
I honest to god think he meant to use the word transmission instead of engine. He even mentions "as if I changed into a higher gear?"
 

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When you are running on the ICE at highway speeds the engine directly drives the wheels in the Gen2 Volt so obviously it's not turning at a single speed, like any ICE it's speed is directly related to the speed of the car. At lower speeds the ICE is just driving the generator and the electric motors are driving the wheels so under those circumstances the engine will turn at a constant velocity.
You completely ignored the first line of my post where I say I'm pretty sure OP is using the term "speed" as in gear or transmission ratio position. This has nothing to do with what I wrote or the actual speed of the engine or vehicle.

All model year volts to date do not have multiple gearing for engine output. The transmission (containing electric motors) is either connected to engine, or not. There's no gear multiplication/shifting/changing ratios in between the engine and the wheels as there is in a traditional ICE transmission. Any adjustment of the energy (engine) output to the wheels is either 1) increasing or decreasing engine RPM or 2) adding or removing energy from the transmission using the electric motors. In a traditional ICE transmission, the engine RPM could remain constant and power to the wheels altered with gear ratio changes. Volt cannot do this. Which is a good thing. It's far simpler.
 

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@ Alfon

What year (or month/year built) is your G2 Volt? When did you have the software update done? I don't think there have been any updates or notices in the past 6 months or so, wonder if GM has the G2 Volt pretty well dialed in by now.
 

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You completely ignored the first line of my post where I say I'm pretty sure OP is using the term "speed" as in gear or transmission ratio position. This has nothing to do with what I wrote or the actual speed of the engine or vehicle.

All model year volts to date do not have multiple gearing for engine output. The transmission (containing electric motors) is either connected to engine, or not. There's no gear multiplication/shifting/changing ratios in between the engine and the wheels as there is in a traditional ICE transmission. Any adjustment of the energy (engine) output to the wheels is either 1) increasing or decreasing engine RPM or 2) adding or removing energy from the transmission using the electric motors. In a traditional ICE transmission, the engine RPM could remain constant and power to the wheels altered with gear ratio changes. Volt cannot do this. Which is a good thing. It's far simpler.
Yes and no. You're correct that the engine gearing is physically the same at all speeds. However, you're ignoring the impact of adding and subtracting at the same time by the two motors. Just like in the Prius, the Volt effectively has a wide range of rpm ratios and torque multipliers when running in power split - the extra torque technically comes fro one of the electric motors, delivered by siphoning off power by the other motor, but in the overall picture it effectively a variable gear ratio.

Here's a nice flash simulator for the Prius, which with minor changes in how the elements are connected to the central planetary set describes both Volts as well (at least when the first generation is in power split mode):

http://eahart.com/prius/psd/
 

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Yes and no. You're correct that the engine gearing is physically the same at all speeds. However, you're ignoring the impact of adding and subtracting at the same time by the two motors. Just like in the Prius, the Volt effectively has a wide range of rpm ratios and torque multipliers when running in power split - the extra torque technically comes fro one of the electric motors, delivered by siphoning off power by the other motor, but in the overall picture it effectively a variable gear ratio.
uhhh... I am?
In addition to running the engine harder when required, the actual manipulation of engine output vs wheel output is maintained by the electric motors, adding or removing energy as required.
This effectively makes it "infinite gears"
.
Any adjustment of the energy (engine) output to the wheels is either 1) increasing or decreasing engine RPM or 2) adding or removing energy from the transmission using the electric motors.
 

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The Volt uses an electronic CVT transmission. It typically runs the engine at the most efficient RPM. Don't worry what it is doing, just drive.

Shifting transmissions are terrible for efficiency because they force the engine to run at inefficient RPMs. They are there because they were relatively straight forward to make. I suppose transmissions like Volt and Prius will take over in the future.

CVT transmissions are better as they vary the gear ratio so the engine can run at efficient RPM. When looking at traditional gas cars this is much better with turbocharged engines as the turbo never loses pressure while shifting like in a classical transmission.

However, people often don't like CVTs as they are weird and don't match what they are used to, so some cars implement fake shift feel modes that actually hurt performance, but make the car feel more normal.

My suggestion is get used to the CVT feel and you won't want to drive anything else.
 

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Shifting transmissions are terrible for efficiency because they force the engine to run at inefficient RPMs. They are there because they were relatively straight forward to make. I suppose transmissions like Volt and Prius will take over in the future.

CVT transmissions are better as they vary the gear ratio so the engine can run at efficient RPM. When looking at traditional gas cars this is much better with turbocharged engines as the turbo never loses pressure while shifting like in a classical transmission.
Technology advances. " Gears change from second- to ninth-gear ratios with precise clutch-to-clutch shifting, where the clutch is engaged in one gear at exactly the same time it is released from another."
Full description: http://media.chevrolet.com/media/us/en/chevrolet/home.detail.html/content/Pages/news/us/en/2016/dec/1206-9speed.html

I've driven a car with this transmission. Works as advertised - shifts are FAST and SMOOTH.
 

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Gen 2 transmission/motor operation is explained here

http://gm-volt.com/2015/02/20/gen-2-volt-transmission-operating-modes-explained/

The 3 motors are connected to a planetary gear set and then to the wheels and use a combination of clutches to tie them together. Depending on the speed, the clutches lock and/or release the inner and outer gears of the planetary gear set to determine which direction and speed range is available.

Planetary gears are very interesting and we're actually developed many years ago.

Google it for some interesting reading.
 

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The Volt uses an electronic CVT transmission. It typically runs the engine at the most efficient RPM...
Not sure what Volt you have but there is no CVT in the G2.

Just the planetary gear set which can be operated in 5 modes. With the engine running and it's clutch engaged there may be 2 different gear ratios depending on if the outer ring is stopped or not.
 
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