Bore Stroke Ratio | Performance Engine life Effects | Applications

In this video, the bore & stroke of an engine and their effect on engine performance, characteristics, engine life, engine application, and cost aspects, etc are explained in detail with simple animation.

Follow us on

[yash_kambli]

2:35 u were slightly wrong here. Piston didn't take more or less time to travel BDC to TDC, they did in a exact same time in either cases only the piston speed is vary. At similar rpm long stroke engine would have much higher piston speed than short stroke, which limits the rpm to go higher.
2. Short stroke engines does suffer from more heat losses due to More surface area is exposed in very beginning of combustion, when piston is at TDC. This is where piston experience highest peak force due to peak pressure.
3. Long stroke engine produces more torque at lower rpm bcoz high piston speed n small valves results in high velocity incoming charge, forming a strong swirl (a turbulent motion) which leads to faster burning. It's very important to minimise heat losses as it reduce the ignition timing. Less heat loss= high peak pressure= high peak torque.

[HoweDoYouDo]

This man should be a professor he just taught me all this shit in a tongue I can actually understand 😂

[sodazman]

Diesel engines produce more torque mainly due to the fuel and compression ratio being typically over 20:1. Also, when you increase the stroke of the engine while keeping the bore the same, the capacity goes up and that increases torque. Hence why companies sell stroker kits for engines. Naturally aspirated F1 cars (V8/V10) produce significantly less torque (around 350nm) than many high performance cars. It makes power (over 700hp) but low torque relatively speaking. However, it doesn't need much torque to move the car due to the low kerb weight and that it exclusively runs at high RPM being a race engine.

[waniiiii]

If I m not wrong, I would like to say that a long connecting rod would result in great efficiency than short because of little angle produced at piston pin. As the push from piston gets split into two components sin and cos . Rest u understand

[Nirojgansi]

4:40 sports car accelerates 0-60 "that fast" because they have more 'Torque'?? The most stupidest answer I have ever heard.. It is the power of the engine that matters, Not torque!. It is the "Torque seen at the Wheel" that determines the acceleration of vehicle, Not torque seen at the Crank shaft!!! Wheel torque highly depends upon "Gear Ratio" of transmission and very little on engine torque. Do more research before fooling innocent people. And yes, longer piston stroke allows greater expansion of burnt gas, producing more "Torque". 4:05 Your imprudent assumption of constant pressure exerted on piston head throughout the stroke length is completely BS!.

[gerritgovaerts]

You forgot to mention piston speed (and its limits) as a factor : over squared engines can run higher rpm's with equal or even lower piston speeds

[JamesKirk]

Very thorough explanation on pros and cons of various ways to size an engine!

[mrvector]

This is one of the best/simplest explanations for stoke and bore. Great video!

[metallica]

Really great video, I am designing 70 HP diesel engine for my project and wanted to read some stuff about bore/stroke on wiki to get introduced to the topic. This gave me much more info in such a less time. Thank you man.

[noelmartin]

Iam happy to be a subscriber to this channel since it started 3 years ago with very few and grew to be one of the great channels explaining automobiles 😀

[Kytes]

In long stroke engines you either put 3 spark plugs, or change piston geometry. Like Mazda did in their engines

[johnbarron]

In engines that have a cast iron block, wouldn't the undersquare design result in less heat loss, since a smaller proportion of the surface area of the combustion chamber is in contact with the more thermally conductive aluminium surfaces of the piston and cylinder head?

[MrAndrius]

This video actually caused me to go and calculate everything for myself, as I have been told before the exact opposite, that longer stroke has less surface area. Funny enough, this video was correct, the one with the bigger stroke has slightly less surface area in the cylinder. Then I looked into big cylinder vs more cylinders (i.e. trucks vs sports cars) and found that with a truck's long stroke (but decent size bore too) giving around 1 liter per cylinder vs a slightly over-square engine with 0.5 liters per cylinder, the truck had around ~90% of the surface area as the sports car. Kind of fascinating and weird at the same time.

[adamarlei]

thank you so much. currently learning on engines and this definitely helps me a lot. thanks once again! subbed!

[KjV]

You explained this much better than Engineering Explained. Plus, your voice isn't annoying!

[zmike]

this video explained a lot of stuff that other people missed, but i also feel that you gave over-squared engines a little to much dirt, i believe both are equal when i comes to reliability, its just usually oversquareds are used in applications were they destroy themself's to do there intended purpose while undersquared engines are used in applications were reliability is targeted or the engine is safe zoned so it cant do such thing.i believe in the end its just preference.

[pareshprajapati]

Thank you 👍🙏 so much
Highly informative educative video
Thank you again

[wickiezulu]

How does cylinder centre distance / bore spacing impact the ability of an engine's ability to grow in terms of further increases in bore and stroke? For example could a 4-cylinder 895cc engine with a 72mm bore x 55m stroke and a 93mm cylinder centre distance have a greater potential of growing larger compared to say the Suzuki G with its 84mm bore spacing at 1.6-litres or a 4-cylinder version of the BMW M20 6-cylinder with a bore spacing of 91mm?

[zvonimirskvorc]

Yeah but 9.0l stroker out of 8.4l viper does produce more tq since piston stroke is longer idk I learn about this stuff in school and come here where you say that engines with longer stroke produce the same tq as the ones with shorter stroke

[aliqadri]

Does petrol engine comes in under squar engine..??