Does the ICE power the vehicle?

Yes, most of the time.

 

Your Prius is a parallel hybrid. This means that the ICE and the electric motors work either simultaneously or each alone to drive the front wheels. A serial hybrid (like the Chevy Volt, if it ever exists) is an electric vehicle that has a separate generator to supply electrical energy supplementing the battery.

JeffD

 

That description of "parallel" is correct, but not for a Prius. That is how the ASSIST hybrids, like Civic and Malibu, operate. The electric motor is an integral part of the system, which means it cannot operate independently.

FULL hybrids, like Prius, have a PSD (Power-Split-Device). This allows the electric motor to propel the vehicle all by itself at times... which is a trait of the "series" design. That's why Prius is technically a "series-parallel" type of hybrid.

.

 

This is more than you asked for, but to expand a bit on the other answers: This might seem counterintuitive, but the value of the Prius' electric motors is not to provide sustained propulsion. Instead, the value is in allowing a smaller and more efficient ICE to be used. If a conventional car of the Prius' weight had the same ICE, it would be woefully underpowered. The electric motors provide immediate and substantial power when needed for short bursts of acceleration.

 

Prius is a series hybrid when reversing. The ICE can come on but it does not provide motive power backward (only forward). The only reverse power comes from the MG2 electric motor. Therefore, ICE is only used as a generator in reverse "gear".

To answer tigerpilot's question, about one third of the ICE torque power the Prius whenever the ICE is running while Prius is moving forward.

 

Most of the time part of the power goes directly from the ICE to the wheels, and part of it goes from the ICE through MG1 to MG2. If extra power is needed, the ICE runs faster, energy is drawn from the battery, or both. If extra power is available, it is used to charge the battery. In limited cases the Prius runs as an electric vehicle with MG2 powered only by the battery. The special case of backing has already been explained.

Tom

 

A Prius will not budge without the larger electric motor running, as it is the one actually connected to the differential. So, even though the car can be propelled with the ICE, nothing moves without the electric.

To get a really good ... with pictures ... idea of how it works, go here Toyota Prius - Power Split Device

Best place to answer your question. Then go here John's Stuff - Toyota Prius and more

Best place for the rest of your questions.

 

I like the term "split-path hybrid" to describe the Prius as it can act like a parallel or series hybrid. It has a mechanical path direct to the wheels and an electrical path like a series hybrid through the motor generators.

A series hybrid has some attractive features in that the car can move without the engine running and the engine speed and road speed are independent but the size of the motor/generators have to be larger as they handle the full power of the car and 20% or so of the energy will be lost in the electrical to mechanical conversions.

A parallel hybrid avoids those problems but has its own in that you cannot have an electric only mode without additional clutches and complexity and optimizing engine operation is difficult.

The Prius has the best of bit worlds - it is designed so that at freeway speeds it acts more like a parallel hybrid with the majority of the engine power going straight to the wheels through the highly efficient mechanical path only losing 5% or so of the power but if needed the electrical path can be used as a transmission to change gearing for climbing hills or as an overdrive to optimize engine efficiency - and at any time additional power can be obtained from the battery or excess power can be saved for later.

kevin

 

Put even more simply, the ICE can power the wheels mechanically, and /or power the wheels electrically though a motor-generator or recharge the battery through that same motor-generator.

And, of course, the battery can power the wheels electrically too. Which is the best part of all. And the wheels can recharge the battery.

 

This is not true. The larger motor-generator, MG2, is directly connected to the differential, but the car can move without it. The ICE is connected through the PSD by way of the planet gears. If MG1 is locked, and MG2 is allowed to free wheel, all of the power from the ICE is mechanically connected to the differential.

Of course all of this discussion is counting the number of angels that can dance on the head of a pin. MG1 can't be locked without the electrical system, the control system is all electronic, and the ICE cannot start without MG1, so nothing will work without the electrical side of the vehicle. I just wanted to make the point that yes, the Prius can be propelled with only the ICE, but the control system would do this only under a very limited set of circumstances.

Tom