Plugin Article - Natonal Post

Oh, and Rogart1, just because Toyota can't make lithium ion work doesn't mean nobody can. You may not have noticed the headlines lately, but Toyota, despite your religiousity, is not infallible.

 

piffle?!? piffle!?! i din't learn that one in 'engineering' school.

 

It comes from the gasoline otherwise would have been wasted. Atkinson cycle gas engine can do more work with the same amount of gas as the Otto cycle engine.

Even the gas engine in the Prius only use 40% of the energy in gas. The other 60% is still available to harness.

 

Before I respond to your article, could you please provide us with some sort of equivalent energy consumption or adjusted L/km figure for your test drives including the wallplug energy? And hopefully, based not just on an assumed 5kWh from the battery capacity rating, but on actual energy use from the wall plug, before AC to battery conversion losses.

Absent the electric energy input, PHEV gas-only mpg and L/km figures are essentially meaningless and a lot of malarkey. As a fellow engineer, I'm sure you will understand why I view them as piffle.

 

Hello, David. It's refreshing to see an author of such a piece post on an enthusiast forum...quite different than the usual hacks. Congratulations. My opinion of you has actually improved, due to your actual presence, here. Thank you for showing us that respect.

Well, that's cute. A bit over-simplified, but almost correct for some of the true believers.

For those of us who are more interested in the bottom line, it's simple. The Prius gets higher mpgs than any other car on the road, and does so with only a minimally-higher MSRP. For me, it makes good *economic* sense to drive a Prius.

Certainly. And, it's nice to know that you have a background in engineering...but be aware that the Prius' engineering gets a bit more complicated than that of a traditional car.

Toyota's hybrid system takes advantage of a number of different power sources, including gasoline, and even gravity (when going downhill, regeneration can kick in) to recharge the batteries.

The true benefit of a hybrid system comes from the overcoming of other inefficiencies. Take for example, the Atkinson cycle engine...it is more efficient than the traditional ICE found in many cars, so it uses less gasoline. Due to the CVT it is possible to run the engine in its optimum range, further increasing efficiency. The partially electric drivetrain also allows further efficiencies, explained below.

On the other side of the equation are the losses...and these have been carefully minimized by the designers. The cD is the lowest among all production cars, and you know that drag is a cubed function. Low rolling resistance tires, etc further improve efficiency. And, yes, regeneration allows the capture/recapture of energy that would otherwise be dumped into the environment.

Finally, the gasoline engine is pathetically small. Inadequate, really. So, why is it designed this way? The hybrid drivetrain allows a tiny engine to operate in its optimum range, keeping the car at speed. When needed, the *supplemental* electric motor kicks in and gives you a burst of HP that would require a larger (and much less efficient) engine.

All these little things add up to one big result...a 5-door family sedan that gets better gas mileage than many motorcycles. Analyze it any way you want...the Prius has the highest mpg rating of any car on the market...using *standard* testing procedures.

The EPA estimates (I am American) are done using a standardized set of parameters...pulsing, gliding, and hypermiling are not among them. By using these techniques we can take the mileage of any car to a point well above its EPA estimates.

By driving it normally, my 2nd generation Prius gets around 45-50mpg in mixed driving. This is in line with the EPA estimates, so they seem to be believable. By hypermiling, some can push this (with relative ease) to near 60. The 3rd generation Prius actually gets *better* gas mileage, and makes it almost impossible to get less than 50. Driving normally.

The point of your article, as it was written, was to slam the Prius and other hybrid technologies. You then included a flawed analysis of how much better a plug in would have to be.

The plug-in *must* do better in your flawed analysis...much of the energy used does not come from the car. You've made the classic mistake. A plug in, or even an all electric car does not have zero-emissions...it has displaced emissions. You simply blew the smoke out of a remotely-located smokestack, rather than your own tailpipe.

And, remember that the Prius drives just like a normal car.

By focusing on enthusiasts who try to pry every bit of extra energy from the fuel, you've focused on too narrow a subculture. The tone of your article implied that these things *must* be done to realize any savings. And, that's simply not true.

It's like saying that all Hondas must be like those modified by Ricers. Untrue.

And, you chose to close your letter with a threat. Is it any wonder that the public no longer reads the newspaper, when it's written by biased opinion-writers like you?

You showed us the respect of coming to the forums and confronting us in person. Let me reciprocate.

If it is your intention to call yourself a journalist, then reporting facts will be of paramount importance. Instead, your piece was biased, plain and simple. Your analyses were flawed, and your assumptions were baseless.

Please go back and reread it with a fresh outlook...your personal opinions come through, loud and clear.

-- Chuck

 

When just reading the first two paragraphs, it was clear that the writer has not fully understood the Prius.

It has been mentioned in prior posts:

One of the main reasons for efficiency is the Atkinson process. Its downside is that the engine has no power at low rpms.
An electric motor is great at low rpms (lots of torque).

Combine those two (well Toyota uses 2 electric motors) and you can have the best from two worlds.

Btw: one downside of a plugin is the weight of the battery. You always have to move the battery - even when driving on gas.

 

Well, this article only proves that we have hillbillies in Canada too.

Maybe I should invest in a 2010 Golf tdi with that snazzy DSG transmission. Then when I get stuck in neutral at highway speeds, or the multi-plate clutch fries in city stop-n-inch traffic, I can cough up thousands for a new DSG

VW DSG Transmission Problem Leads to Recall - Wheels Blog - NYTimes.com

Volkswagen recalls 13,500 DSG-equipped 2009-2010 models over sensor problem — Autoblog

I personally don't mind driving a stick-shift, but why not just use a conventional automatic transmission? With reasonable care they will last a long time. Most conventional auto transmission cars, you don't have to shift into N after 5 secs at a red light, to avoid frying the clutches

 

Thankyou Chuckknight for your intelligent and defferential response.


Motocanada, I am a recent hybrid owner, having purchase a 2010 gen3 Prius less than a month ago. This is my first hybrid and my first Toyota so I am definitely not a fanatic. When I began looking for a replacement for our minivan, improved fuel economy was a major consideration. I looked at "conventional" powertrain vehicles, the myriad of hybrid offerings as well as the Jetta TDI. While I very much liked many of these vehicles (and especially the TDI) I chose the Prius for a number of reasons:
1) The Prius has the best fuel economy, bar-none, of any mass produced sedan aimed at a family of 5, particularly for the 80% urban driving that I do.
2) The Prius (and Toyota in general) while not infallible, has one of the highest overall reliability track records in the business. Certainly the reliability of the Prius is far beyond that of the TDI; it doesn't take very much research to see this.
3) The Prius has been in production for more than 10 years, with numbers exceeding a million so it has been very well acid-tested. Other hybrid offerings are much fresher and have yet to be proven.
4) The Prius represented a practical trade-off between (extra) purchase cost, and returns on fuel savings. For the sake of my children and future grand-children I hope better solutions, whether they be a PHEV or pure EV, do arrive and at a reasonable cost, but they are not here yet for many people.
5) The Prius (and other hybrids) fit perfectly with existing refuelling infrastructure which translates into no compromises when I drive where and when I want.

In the end current hybrid technology, and especially the Prius, is for very many people, the best solution available to "have our cake and eat it too!".

 

careful, we're giving him fodder for more columns. enablers!

 

I have to agree with some of what he's saying, for instance the Transport Canada ratings are 3.7L/100km in the city and 3.8L/100km on the highway. Hyermiling or not NO one gets this...i'm averaging 4.5 (not counting the mileage error that Toyota has put in) which is a huge difference. In my previous non-hybrid car I had no problem meeting the milage ratings of the car....

 

can you translate to mpg?

 

To convert back and forth between l/100 km and mi/US gal divide 235 by the number.

235/3.7 = 63 mi/US gal

I have been able to exceed this for shorter trips. My best leg was 3.0 l/100 km (78 mi/US gal) over 30 km (19 mi) but that is starting with a warm engine and a full battery; and driving like something between a Granny and a Nanny.

Most of my "normal" driving including cold starts has averaged 4.5 to 5.0 l/100 km (52 - 47 mi/US gal) which I believe is consistent with the US EPA ratings...So I think these numbers at least are achievable without excessive hyper-miling techniques...

 

yes, but what other car can you get 4.5L/100km?

 

Well, I've often wondered if our government was full of Granny's and Nanny's. I guess this is evidence that it is!! (lol)

 

that would certainly make for a lot of disappointment!

 

He chose to call it fodder. I choose to call it material. Hopefully his next article will reflect both sides, unlike this one.

 

"I am not a fan of hybrids. Conceptually, I find them flawed, the idea of first having a battery supply power to an electric motor and then later using the gasoline engine to recharge the battery seems like a classic case of robbing Peter to pay Paul.

Were it not for the energy recuperated during regenerative braking and coasting, hybrids would have ........."

The Prius' Peter is quite a bit better endowed than you realize. Missing from your analysis is the simple fact that the Prius ICE *on average* is about 50% more efficient IN ITS PETROL USE than any other regular petrol car used in a 50/50 mixed urban/highway driving. You might honestly question whether the increased efficiency is squandered in energy conversion losses, but I will have to ask why you haven't availed yourself of the answers that have been widely available for 10 years. You could start with knowing that 72% of ICE torque is sent directly to the wheels without any energy conversion at all, or that the power split device (PSD) puts regular transmissions to shame at speeds below 70 mph.

You seem to be guessing that the improved ICE efficiency can only be obtained by unusual driving habits. Others have posted reminders to look at US EPA, which are set up to mirror aggressive driving. I'll also share anecdotaly that I drive exactly in the funny ways you do not want to, but I enjoy 70+ mpg (US) consistently, not the piddly EPA numbers.

The answer to your question is, of course all motive power in the Prius originates from petrol. Now, you answer a question for me: why do you ignore how efficiently the petrol is consumed ?
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I sent my earlier post to Mr. Booth. I hope he responds. I have to say that although I find his reasoning shallow and ignorance troubling given his background and occupation, his prose is a pleasure to read, and he clearly is not stupid. We *should* be able to find rational common ground with this guy.

He is quick to admit that he is a lead-foot, and when all is said and done, he may just say that he does not find hybrids subjectively satisfying to drive. In the meantime though, he finds the tech wanting based on his personal fuel economy results: 6 l/100 km in city driving, which he calls about the same as other regular cars. I wonder about the comparison though. Is he comparing *his* driving in a regular petrol car, to his driving in a Prius, assuming he drives both cars in a similar fashion ?

If so, then his message can honestly be: "if you drive like me, Prius city MPG is not going to improve dramatically over your current economical petrol compact." To that I think it fair to add, "if you drive like the EPA tests, expect around 50 mpg overall; and if you drive for fuel economy using driving techniques described in internet forums like PriusChat, results north of 70 mpg can be obtained consistently in temperate weather once the engine has warmed up."

 

Unlikely.... He writes for the National Post.