Electric Motor - HCH-II vs. Prius
#1
Electric Motor - HCH-II vs. Prius
I just heard, from a Honda "Salesman" If the Prius electric motor fails, the car is inoperative till repaired. The advantage to Honda's Hybrid is if the electric motor fails, you can still operate the car on the gas engine alone.
Is it true the Prius will not run on the engine if the electric motor stops working?
Is it true the Prius will not run on the engine if the electric motor stops working?
#2
Re: Electric Motor - HCH-II vs. Prius
Originally Posted by NovaScotian
I just heard, from a Honda "Salesman" If the Prius electric motor fails, the car is inoperative till repaired. The advantage to Honda's Hybrid is if the electric motor fails, you can still operate the car on the gas engine alone.
Is it true the Prius will not run on the engine if the electric motor stops working?
Is it true the Prius will not run on the engine if the electric motor stops working?
That's not to say the Toyota Hybrid System isn't without its advantages, it has plenty, including reliability advantages and huge efficiency advantages in city driving conditions.
#3
Re: Electric Motor - HCH-II vs. Prius
It would seem to me that of all the things that could go wrong with a hybrid, the electric motor failing should be fairly rare; not something I'd loose much sleep over.
#4
Re: Electric Motor - HCH-II vs. Prius
Originally Posted by NovaScotian
I just heard, from a Honda "Salesman" If the Prius electric motor fails, the car is inoperative till repaired. The advantage to Honda's Hybrid is if the electric motor fails, you can still operate the car on the gas engine alone.
Is it true the Prius will not run on the engine if the electric motor stops working?
Is it true the Prius will not run on the engine if the electric motor stops working?
#5
Re: Electric Motor - HCH-II vs. Prius
[QUOTE=Double-Trinity]This is true as the electric motor (actually, two electric motors) in the Prius are required for the transmission to function. The Prius tranmission is essentially a single gear system. In high gear, it simply tranmsits the engine power mechanically. However, In order to get torque for "low gearing", it must convert some of the engine's mechanical power into electrical, with one motor acting as a generator powering the other. This must happen even if there is no flow of power into or out of the battery. This is also the reasno why the Toyota Hybrid System won't work for off-road driving, where slippy conditons can damage the motors, a true mechanical tranmission would be needed.QUOTE]
My understanding is that the Prius uses a CVT transmission.
You can't get added torque from an engine turning at a low speed by placing more load on it to turn a generator to turn an electric motor. If you disconnect the engine from the trans and use it to supply electricity to turn an emotor, your acceleration is then limited to the emotor's modest horsepower.
My understanding is that the Prius uses a CVT transmission.
You can't get added torque from an engine turning at a low speed by placing more load on it to turn a generator to turn an electric motor. If you disconnect the engine from the trans and use it to supply electricity to turn an emotor, your acceleration is then limited to the emotor's modest horsepower.
#6
Re: Electric Motor - HCH-II vs. Prius
Originally Posted by lifespeed
My understanding is that the Prius uses a CVT transmission.
You can't get added torque from an engine turning at a low speed by placing more load on it to turn a generator to turn an electric motor. If you disconnect the engine from the trans and use it to supply electricity to turn an emotor, your acceleration is then limited to the emotor's modest horsepower.
the prius does employ a continuously variable transmission. the difference is that it uses a planetary gear system versus the civic's belt and pulley system. two very different systems but both are continously variable.
#7
Re: Electric Motor - HCH-II vs. Prius
My understanding is that the Prius uses a CVT transmission.
You can't get added torque from an engine turning at a low speed by placing more load on it to turn a generator to turn an electric motor. If you disconnect the engine from the trans and use it to supply electricity to turn an emotor, your acceleration is then limited to the emotor's modest horsepower.
You can't get added torque from an engine turning at a low speed by placing more load on it to turn a generator to turn an electric motor. If you disconnect the engine from the trans and use it to supply electricity to turn an emotor, your acceleration is then limited to the emotor's modest horsepower.
This site explains how it works, here's an excerpt:
Always in Top Gear
We have discovered above how the Prius transmission uses an epicyclic gear, a generator and control electronics to adjust the spin rate of the engine without the use of either a step transmission or a conventional CVT. We also discovered that a fixed proportion (about 72%) of the ICE torque is sent mechanically to the wheels. Without the ability to change the gear ratio between the ICE and the wheels, we cannot multiply up the ICE torque to get high acceleration at low speed. Although we've solved the problem of letting the ICE spin at a suitable rate when the car is moving slowly, the torque coupling is equivalent to always being in top gear!
This problem is partly solved already by passing generated electricity from MG1 to MG2 which adds its torque to that of the ICE. Electric motors do not share with an ICE the problem of not generating torque at low speed. In fact, this is where they generate the most torque. If we run the ICE at, say, 2000 r.p.m., with the car barely moving, a lot of power passes from the ICE to MG1. In fact, until the car starts moving, all the power goes to MG1. Even though MG1 gets only 28% of the torque, it gets all of the movement! Since MG2, connected to the wheels, is not rotating very fast, it doesn't take much power to generate its maximum torque. The Prius can launch from a standstill at respectable acceleration up to about 15 k.p.h. using ICE power passing primarily through MG1 and MG2. Only about a fifth of the torque comes directly through the mechanical path during this initial acceleration.
We have discovered above how the Prius transmission uses an epicyclic gear, a generator and control electronics to adjust the spin rate of the engine without the use of either a step transmission or a conventional CVT. We also discovered that a fixed proportion (about 72%) of the ICE torque is sent mechanically to the wheels. Without the ability to change the gear ratio between the ICE and the wheels, we cannot multiply up the ICE torque to get high acceleration at low speed. Although we've solved the problem of letting the ICE spin at a suitable rate when the car is moving slowly, the torque coupling is equivalent to always being in top gear!
This problem is partly solved already by passing generated electricity from MG1 to MG2 which adds its torque to that of the ICE. Electric motors do not share with an ICE the problem of not generating torque at low speed. In fact, this is where they generate the most torque. If we run the ICE at, say, 2000 r.p.m., with the car barely moving, a lot of power passes from the ICE to MG1. In fact, until the car starts moving, all the power goes to MG1. Even though MG1 gets only 28% of the torque, it gets all of the movement! Since MG2, connected to the wheels, is not rotating very fast, it doesn't take much power to generate its maximum torque. The Prius can launch from a standstill at respectable acceleration up to about 15 k.p.h. using ICE power passing primarily through MG1 and MG2. Only about a fifth of the torque comes directly through the mechanical path during this initial acceleration.
Also, the fact that this system cannot run wihtout electric motors is relevent, even though electric motors are likely the last thing that will fail in normal driving -- the electric motors run the risk of overheating in offroad situations where they have a chance of being stuck in the mud for example. While this would not be a problem for a normal car, it could fry an electric motor trying to produce all that torque. That's why you won't be seeing any offroad-capable hybrid trucks using Toyota's system. However, Honda's system would potneitally work in a truck for going offroad as even without electric motors running, it can gear down the engine.
Last edited by Double-Trinity; 04-21-2006 at 08:17 PM.
#8
Re: Electric Motor - HCH-II vs. Prius
I think i bought the wrong car,
someone help me out, i live a very dense and populated city with excellent roads but i work up on top of a really high and muddy mountain.
do i run a risk of destroying my electric motor?
would it help if i had bought a tank instead?
someone help me out, i live a very dense and populated city with excellent roads but i work up on top of a really high and muddy mountain.
do i run a risk of destroying my electric motor?
would it help if i had bought a tank instead?
#9
Re: Electric Motor - HCH-II vs. Prius
Originally Posted by CamelFilters
I think i bought the wrong car,
someone help me out, i live a very dense and populated city with excellent roads but i work up on top of a really high and muddy mountain.
do i run a risk of destroying my electric motor?
would it help if i had bought a tank instead?
someone help me out, i live a very dense and populated city with excellent roads but i work up on top of a really high and muddy mountain.
do i run a risk of destroying my electric motor?
would it help if i had bought a tank instead?
#10
Re: Electric Motor - HCH-II vs. Prius
Cool
I was going to go out and trade my Prius for a Hummer
Or better yet, i'll just go capture one of those mountain goats and ride on their backs all the way up the mountain.
I was going to go out and trade my Prius for a Hummer
Or better yet, i'll just go capture one of those mountain goats and ride on their backs all the way up the mountain.
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