Bore & Stroke Values

See each mfr's respective fuel consumption data.

See how often each fuel delivery system needs to be examined and adjusted.

Contact the manufacturers and ask them.

Or use the internet for something other than asking others to look it up for you.

I have done the initial search for you, now it's up to you.

Diesel Engines | Cummins

Cat | Power Systems | Caterpillar

i have these documents with me, if you check i have mention bore and stroke sizes taken from these websites, what i am asking is basic theory behind this.

irrespective of manufacturing i requested for basic theory.

cummins consume 300 ltr per megawatt

catterpillar consume 260 liter per megawatt

thanks

Go with the Cat one, less fuel, same power output, probably less rpm to wear out more slowly. Neither one is reliable if no maintenance program in place.

The more powerful will have the highest torque rating....the most reliable one will be the one best maintained....Generally speaking, for similar displacement engines, the one with the larger bore and shortest stroke will produce the most torque and have lower RPM and more narrow torque range, the more narrow bore with longer stroke will have higher speed with broader torque band over higher RPM range...These 2 engines having similar total displacement and power will probably be close in fuel usage...

It has been 2-1/2 decades since I built my own engines for drag racing using pre-assembled component kits for stroke - you only had to have the bore changed to match the pistons. I probably forget more than I learned, but I think I remember an adage that a "square" engine was never to be built, (same bore as stroke) which the OP has. Of course, that was for developing top end speed more so than low end torque, which is the opposite of what is needed here.

"The Ford 5.4L Modular Engine features a cylinder bore of 90.2mm (3.552 in) and a stroke of 105.8mm (4.165 in), (undersquare) which makes a bore/stroke ratio of 0.852:1. Since the stroke is significantly longer than the bore, the SOHC 16V (2-valve per cylinder) version of this engine is able to generate a peak torque of 350 lb·ft as low as 2500rpm."

"Nissan's SR16VE engine found in Nissan Pulsar VZ-R and VZ-R N1 is an oversquare engine with 86 mm bore and 68.7 mm stroke, giving it an impressive 175-200 hp but relatively small torque of 119 lb.ft-134 lb.ft

Extreme oversquare engines are found in Formula One racing cars, where strict rules limit displacement, thereby necessitating that power be achieved through high engine speeds. Stroke ratios approaching 2.5:1 are allowed, enabling engine speeds of 18,000 RPM while remaining reliable for multiple races.^[4]"

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

Haha...

http://johnmaherracing.com/tech-talk/the-square-engine-myth/

Another Urban legend dies.

...or vice versa...

A seemingly simple enough question, but the answer is not... Here's a few things to consider;

Displacement is a start, does it have a turbo? Efficiency, such as number of valves, engine back pressure;

- Increased pumping work

- Reduced intake manifold boost pressure

- Cylinder scavenging and combustion effects

- Turbocharger problems

ratio (beyond the engine and through out the drive train.

Your question is like " Which do you think is heavier 1 kg cotton or 1 kg nails?"--you already stated the answer.
The shorter the stroke the higher rpm to maintain power. Wear and tear is a function and directly proportional to engine speed.
The numerous the cylinder, the more expensive it is talking about the initial cost of investment, also maintenance cost, consequently.
As to what extent the difference is, I don't know. It's wise to see further documentation of test from the maker.

Assuming the same cylinder pressure, the torque should be proportional to stroke x bore squared x number of cylinders. Power is proportional to torque x rpm.

A longer stroke means the cyclic motion of the piston is greater and the stress on the rod bearings is proportional to stroke x rpm, so shorter stroke engines can run faster with the same amount of stress.

Of course, more cylinders means more initial cost and more maintenance cost, as others have pointed out. There are a lot of trade offs.

I'd rather be stroked than bored, but that's just me.

In general large bore and short stroke would be used for high revving engines and small bore with long stroke for lower revving engines. One factor is piston speed.

For engines designed for fixed RPM such as generators there is a considerable range bore/stroke combinations that will be satisfactory.

This is the sort of question that can only be arrived at by practical experience.

As the two installations would appear to be at the same facility, why not let the forum know the answer in 10 to 15 years' time?

they are not in same facility,

we provide rental power with cummins,

caterpillar is our competator....

I am also not a mechanical engineer, but it's obvious to me which engine is better.

Advantage number 1: Go with Cummins over Caterpillar. Caterpillars are slow moving bugs. Why would you choose that over a Cummins?

Advantage number 2: A V-12 engine has 12 pistons, while a V-16 has 16. Here in the US, we're taught that "more is better", so Cummins wins on this one also.

Advantage number 3: Bore 170 is a lot of bore - a very boring engine. 158.8 is a smaller bore, thus a less boring engine. This subject is boring enough, so why not choose a less boring engine? Cummins wins a third time.

Advantage number 4: Here in the US, the term "Stroke Me" is used by kids and adults all the time - I won't go into details of what it means, but if you don't know, just think about why this works for men and not women. So having a bigger Stroke means more energy is needed to Stroke someone. More energy required = more fuel used = less fuel efficient. So for the 4th time, Cummins wins again.

I think this is enough information for you to choose a Cummins over a Caterpillar.

<Beam me up Scotty>

Live long and prosper \_/.