Toyota's approach to improving ICE efficiency

[easythereturbo]

Originally Posted by redpoint5

I don't get the appeal of powerful sedans. It's pointless in that a sedan is a practical vehicle, made uselessly fast and expensive.

I would argue that modern base-engine sedans *are* powerful as well as affordable. 0-60 in under 8 seconds used be considered quick. Fact, its just as quick as it ever was, its just that people are power drunk these days.

[cRiPpLe_rOoStEr]

Originally Posted by easythereturbo

people are power drunk these days

Absolutely. Personally, I prefer a lower-power, lower-revving engine with some greater low-end torque than a high-power, high-revving one with such a low torque. I see it comparing some 1.0L engines fitted to small cars in my country due to fiscal benefits, while a 1.2L or 1.4L with a similar power rating and more torque could do better.

[ECONORAM]

I saw this article the other day about Mazda's new engine... Mazda

[Frank Lee]

Originally Posted by cRiPpLe_rOoStEr

Absolutely. Personally, I prefer a lower-power, lower-revving engine with some greater low-end torque than a high-power, high-revving one with such a low torque. I see it comparing some 1.0L engines fitted to small cars in my country due to fiscal benefits, while a 1.2L or 1.4L with a similar power rating and more torque could do better.

Example: Ford Tempo. Intended to be mated to old-school 3-speed no lock-up no OD a/ts, it's 2.4 was tuned for low and mid-range torque vs high rpm horsepower. The result? It was a sales leader for many years in spite of nearly universal disparaging publicity in the motoring press about it's "tractor engine".

[elhigh]

Originally Posted by serialk11r

What is really interesting is that Toyota is sticking with relatively large displacement NA when Honda is committing to small turbo engines.

It's been my impression that greater volume in the cylinder = less cylinder wall per unit of volume through which to lose heat. When Deere was still using two cylinder engines, one of their biggest tractors at the time set a record for fuel efficiency that wasn't broken for over 25 years. Each cylinder displaced about three quarts - seriously, each cylinder displaced more than my truck's entire engine.

Turn up the compression, keep the cylinders big, employ Atkinson cycle because that works, laugh all the way past the gas station on your way to the bank.

[cRiPpLe_rOoStEr]

Originally Posted by elhigh

It's been my impression that greater volume in the cylinder = less cylinder wall per unit of volume through which to lose heat.

Makes sense.

When Deere was still using two cylinder engines, one of their biggest tractors at the time set a record for fuel efficiency that wasn't broken for over 25 years. Each cylinder displaced about three quarts - seriously, each cylinder displaced more than my truck's entire engine.

Match the bigger cylinder displacement with a fewer amount of cylinders, and it ends up decreasing the overall amount of internal friction spots.

[elhigh]

Originally Posted by Frank Lee

...The result? It was a sales leader for many years in spite of nearly universal disparaging publicity in the motoring press about it's "tractor engine".

"Americans buy horsepower but drive torque."

Torque output of the HSC engine available in the old Tempo/Topaz twins was modest but decent at about 125-130 ft-lbs.

[Grant-53]

Decades ago SAAB or Volvo figured that 36 lbs per horsepower was ideal. I rarely get my engine (Dodge 3.3L) above 3600 rpm and cruise at 2500 rpm.

[cRiPpLe_rOoStEr]

Originally Posted by elhigh

"Americans buy horsepower but drive torque."

The late Carroll Shelby would say "horsepower sells cars, torque wins races". Soichiro Honda would strongly disagree with that

[Ecky]

Probably best to look at torque after the transmission. Two 200HP motors, one with twice the torque at the crank and the other with twice the RPM, both have the same output after gearing.