Is an Inline 4 better than a V6

[sprintcyclist]

My thinking is a normal 4 cyl is a better design than a V6

[Baronvonrort]

It depends on what job the engine is required to do.

Optimal cylinder capacity for efficiency from a friend who was a F1 engineer is 338 CC per cylinder. When F1 was limited to 3500 CC engines they were V10. When they dropped the capacity to 2400CC they all went V8.

For a motorbike i would go inline 4 the flat 4 used in BMW are too wide limiting cornering lean angles, in a car a flat 4 would be better for smoothness and vibration with lower centre of gravity.

I prefer a V6 to straight six they're shorter better packaging.

If you were to compare current inline 4 to V6 or inline/flat 6 with both engines having capacity around 2400 cc then the V6 would be more efficient more power and torque due to 2 extra cylinders going bang every cycle helping crankshaft turn.

I have a V8 Torana which is really 2 inline 4 cylinder separated by a bank angle sharing common crank, a neat way of packaging engines with large capacity.

[sprintcyclist]

It depends on what job the engine is required to do.

Optimal cylinder capacity for efficiency from a friend who was a F1 engineer is 338 CC per cylinder. When F1 was limited to 3500 CC engines they were V10. When they dropped the capacity to 2400CC they all went V8.

For a motorbike i would go inline 4 the flat 4 used in BMW are too wide limiting cornering lean angles, in a car a flat 4 would be better for smoothness and vibration with lower centre of gravity.

I prefer a V6 to straight six they're shorter better packaging.

If you were to compare current inline 4 to V6 or inline/flat 6 with both engines having capacity around 2400 cc then the V6 would be more efficient more power and torque due to 2 extra cylinders going bang every cycle helping crankshaft turn.

I have a V8 Torana which is really 2 inline 4 cylinder separated by a bank angle sharing common crank, a neat way of packaging engines with large capacity.

Thanks,very interesting.
' ......... Optimal cylinder capacity for efficiency from a friend who was a F1 engineer is 338 CC per cylinder. ..........'

Sometime ago I heard the best size for a 4 cyl was less than 2 litre,about 1800 cc.
I had one like that, it was a great motor.
A mate of mine had a 3.6 litre v8, he loved it.

[sprintcyclist]

Found some other info

A decade or so ago, a team of German university scientists settled on 500 cubic centimeters as the ideal per-cylinder displacement for internal-combustion engines. A 500-cc cylinder with a stroke length larger than its bore diameter, these forgotten pioneers concluded, benefits the combustion process by minimizing the engine’s internal surface-to-volume ratio as the piston nears top dead center. Seeking to optimize power and fuel efficiency while reducing emissions, the three local powerhouses—BMW Group, Mercedes-Benz, and Volks­wagen Group—promptly joined the 500 club with boosted, direct-injected, long-stroke engines. Fiat Chrysler, Jaguar Land Rover, and Volvo are also applying for membership. Additional brands will surely follow, in part because 500-cc-displacement intervals align nicely with existing global taxation statutes. While hybrids and electrics will assist the move to better mileage with lower emissions, updated versions of Nikolaus Otto’s 139-year-old engine—many with 500-cc cylinders—will continue to do the heavy lifting.
Thus far, BMW is the most enthusiastic proponent of the 500-cc cylinder, with half-liter-based three-, four-, and six-pot gas and diesel engines either in production or about to be introduced. BMW’s newest family of TwinPower Turbo gas engines, which launched in the 2015 Mini Cooper Hardtop, shares its 82-mm (3.23-inch) bore and 94.6-mm (3.72-inch) stroke dimensions, plus direct fuel injection, variable intake- and exhaust-valve timing, and variable intake-valve lift systems. This modular approach enables 60-percent commonality of the component parts across three gas engines and 30 to 40 percent with the corresponding two diesel engines.

It’s not just the 500-cc displacement that matters, but also the dimensions that yield such volume. While a cylinder with a smaller bore than stroke (a so-called under-square design) contradicts the classic approach to maximum power at stratospheric rpm [see “Different Strokes”], there are compelling reasons for this move. A small bore shortens the flame travel needed to consume the fuel-air mix and diminishes quenching of the flame at the bore’s periphery. With smaller piston crowns and a more compact combustion chamber, there’s less heat lost to the cooling system. Smaller bores trade shorter overall block length for a modest increase in height, handy for jamming potent engines into tight confines.

One hardship enthusiasts must bear is slightly lower redlines. In exchange, we get better mileage (when we can resist the urge to pin the throttle) and enhanced flexibility attributable to the broader spread between torque and power peaks. Considering the global statutes in place mandating higher efficiency, we’re happy that Otto’s engine has more life left in it.

https://www.caranddriver.com/news/a1535 ... ne-design/

[sprintcyclist]

perhaps 338 cc is most efficient in terms of power per cylinder? Given a small piston can be revved higher?

For fuel efficiency, a differnet size maybe better.?

[sprintcyclist]

Ah,well, i might have to reconsider the idea of 'most efficient'

The current most efficient ICE is a Wärtsilä 31

[sprintcyclist]

Shouldas guessed

Toyota creates world's most thermally efficient 2.0-liter gas engine

40 % !!!!!!!!!!

[sprintcyclist]

All V6 engines— regardless of the V-angle between the cylinder banks— are subject to a primary imbalance caused by each bank consisting of an inline-three engine, due to the odd number of cylinders in each bank.
Straight-six engines and flat-six engines do not experience this imbalance.
To reduce the vibrations caused by this imbalance, some V6 engines use counterweights on the crankshaft and/or a counter-rotating balance shaft.


https://en.wikipedia.org/wiki/V6_engine

[Juliar]

Whereas a mighty V8 is inherently balanced.

Are there any hybrid V8's ?

[sprintcyclist]

Whereas a mighty V8 is inherently balanced.

Are there any hybrid V8's ?

yup



I think V8s get a ...... relaxation for imbalance or not.
Due to them being a V8. The V8 rumble gives them a pass.