Last post on Sep 26, 2008 at 7:53 AM
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#409 of 418 Re: "HSD not to be capable for heavy vehicles" [toyolla2]
Jul 24, 2008 (1:41 pm)
I think there is a need to change our attitude, in what actually constitutes performance, from power towards fuel economy.
Why do people insist on believing that power and fuel efficiency are contrary to one another? If you increase the efficiency of an engine it will almost certainly end up being more powerful. A good example of this is computer controlled fuel injection. This was driven by a desire to improve fuel efficiency but the inevitable outcome was engines that now produced more power.
As an experiment I'd like to see someone pull the 1.5L engine out of a Toyota Yaris and use it to replace a Toyota Camry's 2.4L engine. Certainly a significant difference in displacement and power. I'd be willing to bet that the the mpg improvement would be negligible, maybe non-existent.
#410 of 418 Re: "HSD not to be capable for heavy vehicles" [tpe]
Jul 24, 2008 (1:55 pm)
TPE trying to accomplish too much from a small engine almost always results in a reduction in fuel efficiency.
If your experience is with vehicles from the D2.8 I might have to agree with you. I am told their small engines are a lot less sophisticated than their larger ones since they equate small with cheap and build accordingly. At Ford they are fixing that, and at Chrysler they've already gone to double VVT on many of their smaller models I notice.
The principle of the full hybrid is to sit the engine at the lowest rpm it can - that will just barely support the load. The engine cannot help but be efficient. You are trying to make the case that a larger engine running even slower will be even more efficient here ?
The Prius and Hybrid Camry don't bear that theory out.
The popular dinosaur transmission, on the other hand, has to leave at least 50 to 60 % capacity available to improve driveability ; thus avoiding the need to change down quickly should sudden acceleration be called for. The engine particularly on the hiway is therefore kept running much faster than it needs for the power being generated. A larger engine must incur larger losses it stands to reason.
#411 of 418 Re: "HSD not to be capable for heavy vehicles" [toyolla2]
Jul 24, 2008 (2:03 pm)
One way to examine the size vs. mpg question is to look at the carmakers' European web sites - there they have a good range of engine sizes, often using the same technology, and for a given car there's a pretty consistent relationship of bigger engine = higher fuel consumption (lower mpgs). Sometimes not by much, but the relationship typically holds.
#412 of 418 Re: "HSD not to be capable for heavy vehicles" [texases]
Jul 24, 2008 (2:47 pm)
there's a pretty consistent relationship of bigger engine = higher fuel consumption (lower mpgs). Sometimes not by much, but the relationship typically holds.
The key is "not by much". Look at some popular vehicles that offer 6 and 4 cylinder engines like the Camry and Accord. Yes the 4 cylinders do better in terms of mpg but not by much when you consider the significant difference in displacement and power. Do we need to be able to go from 0-60 in under 7 seconds? Absolutely not. My point is that we aren't giving up all that much for this power. A lot of times a new model will come out that has 10% more power than the preceding model. I hear comments that the auto manufacturer should have instead offered 10% better fuel efficiency as if this a one for one trade-off. It isn't even close.
As long as our most popular vehicles weigh 3,300 lbs or more there won't be much, if anything, gained in going to smaller engines. Now if we get vehicle mass down to around 2,500 lbs then I'll change my position. I suspect that if you tracked engine displacement relative to vehicle weight over the years our current vehicles are near an historic low. The fact that they are more powerful is just a testament to improved engine efficiency.
#413 of 418 Re: "HSD not to be capable for heavy vehicles" [tpe]
Jul 24, 2008 (2:53 pm)
No arguement here - the Toyotal 3.5l V6, for example, is amazingly efficient for the power it puts out, I'd pick it in a second over the (slightly) more economical I4.
#414 of 418 Re: "HSD not to be capable for heavy vehicles" [toyolla2]
Jul 24, 2008 (3:22 pm)
"It's more than likely this new engine was of a more advanced design as well."
Oh yes, they added VVT to the new 2.5L engine. But my point is still valid - smaller is not always better. I don't know what would have happened if they could have put VVT on the current 2.4L, but engines tend to move on once they get past a certain design point, and the 2.5L is the new engine for the Escape.
#415 of 418 Good point that was missed.
Jul 25, 2008 (9:30 am)
Someone mentioned that the average new car is weighing about 3,000 pounds and I think this is completely out of line. A 2 door sports car like the Ford Mustang should weigh well under 2,000 pounds, not almost 35000!
One of the biggest hurdles to getting better fuel economy is how much weight has been added to vehicles over the last 10 to 15 years. Most of this weight is added structure for better crash test performance as well as the weight of more options and equipment.
I think the auto industry needs to spend some time using more modern materials like ultra high strength steel and even some exotic materials.
Ford is only just starting to do this, the 2008 Focus drops 100 pounds vs the 2007 through strategically placed pieces of ultra high strength steel. This isn't so much new technology as a willingness to spend the engineering resources to make the effort work.
#417 of 418 Weird story
Sep 26, 2008 (7:53 am)
Nothing like an argument with a COMPLETE STRANGER to start your day !!
I was leaving the QT this morning with my newspapers, and a 60-something lady two cars over who was walking toward the store paused and said,
She: "Is that your hybrid?"
She: "What kind of mileage are you getting?"
Me: "About 35"
She: "I'm getting 35 in my little Chevy (she points at her Cobalt LT hatchback) and I paid $8,000 for it. You got screwed."
And she started walking toward the store again.
Now, having owned hybrids for more than 4 years, I am pretty much accustomed to people asking me about hybrids and being "positive" about it and complimenting it, or whatever. But I have to admit: This is the FIRST time someone has come at me with a negative. I was a little taken aback.
She kept walking and saying something else with her finger in the air, something about "General Motors" or something.
Me: "No, you got screwed. I've got a big, nice car and all you have is a crappy little Chevy."
In afterthought, I came up with some GOOD comebacks, but at the time, she was practically in the store and I was needing to leave.
I could have said:
"My car is Bigger. Nicer. Faster. Quieter. Holds it's resale value better. Pollutes less. Is far far nicer looking. Has a better stereo. Has a better climate system. Has a bigger trunk. Will spend far less time in the shop than a Cobalt. You get what you pay for and my car IS three times better than your car in almost every way."
I could have said:
"So if I buy a Vespa for $4,000 and get 70 miles per gallon does that mean every owner of a Cobalt got screwed?"
Very odd to start the day with an argument with a stranger.