They would have a good argument until it came time to discuss the definition of “best”.

Ya, I know they can make some really great numbers, but reliability is REALLY big for me, along with long term cost of operation.

My experience says that GM’s eights are as reliable as anyone elses modern eights, but they are a lot cheaper in the long run. Too bad I can’t trust the rest of the car to be better than those mentioned by you. Well, okay, GM electrics are better as well.

I would rather buy a BMW than any of the cars you added, and rather than a GM, but I avoid their 8 cylinders and go with the straight sixes. They make great sixes.

Until Honda makes an eight, I will still consider GM top dog in that arena.

“A gas ICE engine runs most efficiently (least wasted energy) at fairly high power levels. That’s why small engines working relatively harder are more efficient than a lazy big engine.”

Don’t think so. The most “efficient” running of a gas ICE engine occurs at low rpm and wide throttle opening, assuming some attention has been paid to valve timing and lift, so that one is not too far from the peak torque.

Why?

1. Low pumping loss because the throttle plate is nearly out of the way of prevailing airflow into the cylinders at wide throttle opening, making it more diesel-like, because they have no throttle at all.

2. Low rpm minimizes friction losses with respect to piston rings sliding along cylinder walls, and low rpm is easier on bearings and oil films due to the lower dynamic loads.

In addition, a large cylinder has a smaller surface area compared to its volume than does a small one, so less heat is rejected proportionally to the cooling system, and more goes into mechanical work. So, fewer bigger cylinders are more efficient for a given displacement.

All this I learned 40 years ago on an engine dynamometer. Austin engine of 948 cc, versus a Volvo of 1780 cc and a 272 cu in Ford V8 The Ford had the least specific fuel consumption, that is pounds of fuel consumed per horsepower per hour, which cheesed me off, because I was a Volvo enthusiast.

If you think about it, it makes sense. The trick is really to optimize engine size versus rpm required, and the weight of the resulting engine block, which dictates the size of the vehicle it is installed in.

I think we’ve all heard about GMs aluminum V8s. They’re pretty damn efficient being physically small and able to produce enough power to cruise a car at 70 mph at about 12 or 1300 rpm, with a relatively wide throttle opening.

On the aeronautical side of things, during the second world war, both the RAF and the USAAF had to try to persuade pilots to minimize rpm and maximize propeller pitch with WOT to maximize cruising range. Apparently, most guys just wanted to wind the engines up and didn’t like “lugging” them. Nice thought, but wrong if you want to get back home again.

In my new car, one can watch the fuel consumption in real time. At 40 mph, from 2nd through 5th, the mileage increases (consumption lowers) as one goes up each gear, and the rpm lowers. And this happens even though only second gear is anywhere near the published maximum torque peak rpm for the engine, (although it does have variable intake valve timing). That’s the actual real world for you.

As a further point, people have complained about the mileage of a Smart Car versus the Honda Fit or Toyota Yaris. You have to flog the Smart to keep up, while the “big” lazy engines of the Japanese cars are just easing along by comparison.

So what does HCCI actually do again? Ah yes, work at low rpm like a diesel, but over a very limited rpm range. Makes sense to me.

Seriously, can’t stand anything about the whole company but they do make the best V8 engines on the planet.

I don’t think it’s fair to say it’s limited to non-hybrids, only that it’s not as necessary to a hybrid vehicle. One of the more useful aspects of a good hybrid design is that it can choose the most efficient method of power generation given different scenarious. If one such scenario is “the battery has no useful charge” then you have the option to use HCCI at low load until the battery is ready.

Assuming (and I don’t know enough to say) HCCI doesn’t have serious issues in such temperatures, this might be one way to improve hybrid mileage in winter.

Side question: Any idea what the ratio of fuel to energy output would be for HCCI at low revs versus spark ignition at high load? Or will spark ignition at high load always be the most efficient choice?

HCCI offers a substantial improvement only at lower power levels, but intrisically offers no real improvement potential at high levels. That’s why in hybrids, the goal is to keep the engine in a higher power level when possible. So its benefit is intrinsically limited to non-hybrid vehicles.

GM has been runnig the Hydrogen vehicles for months now. If there ever is an infrasturcture, they’re there. Same with E85. Silently GM has had them in trucks and cars for years; successfully. But didn’t get the cheerleaders.

First with an all electric vehicle; before it was popular.

Give em a break guys.

Or they could be keeping their corporate mouths shut until they really have something to say, unlike GM.

It’d probably do well in a pseudo-parallel car like the Prius; the powertrain manager would choose the appropriate combination of power source and behaviour depending on the circumstances. It’s not quite as straightforward as a series hybrid, but it would still work.

Plus it’d have the benefits of the gas engine directly driving the wheels when appropriate, and without losses inherent in a series drivetrain.

It might help put GM back at the front (or somewhere near it) of the technological advances.

There is one thing bothering me. Ford, Nissan, Honda, Volkswagen and Toyota have been TOO quiet about HCCI. Have they made NO advances?

Therein lies the rub. It only works at idle and very low engine output levels. Which is where stop-start and hybrid technology work, and probably more effectively (overall).

It’s a good addition to the mix of technologies available, but don’t expect too much.