Question about the Prius transmission

there has never been a manual transmission for the Prius, perhaps he was confused with the Honda Insight.

 

Sure it's a transmission. It just isn't an automatic or a manual.

 

A transmission is whatever delivers power from your prime mover to the driving elements, while adapting the speed and torque of one to the speed and torque at the other, always preserving (speed x torque out) = (speed x torque in) - inefficiency.

The Prius transmission does all of that, no less than any other transmission. It just happens to have essential parts that are found in a shiny box above the gear housing, and a smaller box under the passenger front carpet. The notion that it's somehow not-quite-a-transmission comes up when ignoring those parts and trying to think only of the gearbox. It's a more interesting transmission than that, but certainly a transmission.

(What's the prime mover then? Ultimately only the combustion engine; the battery both sources and sinks some power at times, with a long term average of zero -- minus some inefficiency. On shorter time scales, any net output from the battery just goes on the same side of the = as the combustion engine output. And there, in a nutshell, is your Prius.)

-Chap

 

The Prius has always been available only with the HSD. None of the Prius models featured a manual transmission, conventional automatic transmission, or a belt CVT.

Tom

 

Wow, way to make friends and influence people!

 

Not impossible, just unnecessary.

 

Ok, I'm a guilty party, and while Evan didn't actually ask me why I had responded as I did, his diagnosis is spot on. The forum serves kind of a dual purpose: 1. get a poster's question answered, and 2. preserve information for the benefit of later readers. Your post contained one straightforward yes/no question, which I could see had already been given a complete and correct answer by morpheusx not 25 minutes after it was posted. But if the thread had ended there with no one addressing the first sentence, later readers may have been misled. So far, 377 people have viewed this thread; some may be new, unfamiliar with the Prius, or even trying to shed misconceptions they have picked up elsewhere. While the first sentence may have been a casual side point for you, too incidental to "fixate" on, that doesn't make it any less likely to mislead another reader who might not know better. So there was a reason for addressing it. If I had seen brick's shorter response I probably wouldn't have spent the time writing another, but I think they crossed in the aether. I'm sorry if it seemed like a lecture at you. It was more about keeping the record straight.

Regards,
-Chap

 

I found your post useful. I especially liked the last paragraph, for all the wizardry that makes up a Prius, it still ultimately runs on gasoline.

 

Exactly: +1 on the good post.

For PaulHS: Please don't think we are a bunch of grumpy old men. The comments about the dual nature of the forum are true. I battle with this all of the time. As an engineer, I am very technical by nature, so I tend to give people more details than they want or need. On the other hand, if I don't, I may mislead someone and have one of the other technical PC members jump on me for being inaccurate of incomplete.

Poorly worded questions are a big problem, and fairly common. We spend a lot of time and forum space wading through BS trying to understand the real issues. Sometimes we get a little snappy if we have to do it too often.

Don't take any of this personally. We are happy to have you here on PC and look forward to your future posts.

Tom

 

I agree.

I read the question much as ChapmanF did which, I thought, raised a question as to whether the Prius has a transmission. I was interested in, and educated by, Chapman's helpful explanation.

That's the beauty of the internet - these threads take on a life of their own. While the original poster may deserve an answer, that doesn't mean he "owns" the thread and can take on the role of the "thread police."

 

Who said anything about design changes or efficiency? I was just making the point that a Prius with a manual transmission is not impossible.

 

How would it be even possible? In traditional transmission, the car shifts gears from a single power source.

In HSD, the car shifts between the two power sources. Computer balances power transmission between electric and gas power to produce the right amount of torque at certain hp level.

If the driver were to manually control these, he'll need to control:
- Gas engine RPM [control gas engine power]
- MG1 RPM [control power split from the gas engine]
- MG2 RPM [control power draw from the HV battery pack]

The driver only has two foot, not to mention the brake. I would say it is impossible.