EngineDesign #V8VsV12 #EngineDisplacement #CarEnthusiasts
What is Engine Displacement? 🛠️
Engine displacement is a term used to describe the total volume of all the cylinders in an engine. It’s usually measured in liters or cubic centimeters. Displacement is crucial because it directly impacts engine performance, fuel efficiency, and emissions.
Why More Cylinders? 🤔
Adding more cylinders is generally about achieving smoother engine operation and higher performance. Here’s why:
- Smoother Power Delivery 🌟
- Reduced Vibration 🔧
- Greater Power Potential 🏁
However, there’s a twist when it comes to displacement.
Smaller Displacement, More Cylinders? 🚗
Why don’t manufacturers produce V8 or V12 engines with smaller displacement, like 2 liters? Here are some factors to consider:
- Complexity 🛠️: More cylinders mean more moving parts, which complicates the engineering and increases the likelihood of something going wrong.
- Cost 💸: Producing an engine with more parts is typically more expensive. Factories have to consider manufacturing costs.
- Fuel Efficiency ⛽: Generally, more cylinders mean more fuel consumption, which contradicts goals for fuel efficiency and eco-friendliness.
Efficiency Dilemma & Balance 📊
Car manufacturers aim for a balance between power, efficiency, and cost. Smaller, powerful engines use technologies like turbocharging to boost performance without increasing displacement or cylinder count.
Performance vs. Efficiency 🔄
High-performance cars, like sports cars, can afford the luxury of multiple cylinders because the focus is on power and performance. But everyday vehicles prioritize fuel economy:
- Turbocharging 🌬️
- Direct Fuel Injection ⛽
- Lightweight Materials 🚗
Practical Examples 🏎️
Here are some examples where these principles apply:
- Turbocharged 4-Cylinder Engines: Common in modern cars, offering great fuel efficiency and adequate performance.
- Hybrid Engines 🌐: Combine smaller engines with electric motors for a balanced approach to power and efficiency.
Final Thoughts 💡
Creating an engine with many cylinders and a small displacement is technically feasible, but not practical for everyday cars. High complexity, higher costs, and lower efficiency make it an unattractive option.
In the end, whether your ride is about speed or sustainability, there’s an engine out there that fits the bill. Manufacturers continue to innovate to find that sweet spot between performance and practicality.
Got Questions? 🍀
Feel free to drop any questions or comments below! 🚗💨
Various forms of efficiency, mostly. More cylinders will almost certainly increase the costs and complexity of building and maintaining the engine. Such an engine would almost certainly be larger and heavier than one with the same displacement, but fewer cylinders. The engine would also be less fuel efficient and probably suffer faster wear. Most consumers (and regulators) value these considerations more than power.
Honda made a 6 cylinder 125cc race bike back in the 60’s .. I think it used to stall at under 10,000 RPM.. had almost zero flywheel inertia.
more moving parts means more expensive, big cylinders are cheaper and more torque which is more important to a daily driver than being able to reach peak HP at 150mph. Bugatti makes a 16 cylinder engine but that has more to do with a 1800hp engine shaking violently and making your teeth chatter.
Basically because a simpler engine with fewer cylinders (4-6) can be designed with the desired power output. So the more complex one is unnecessary
People have said cost and complexity. In addition, the square v cube law is going t work against you. Small things have more surface (the metal in this case) relative to volume (amount of air & fuel which largely determines the *hosspower’ses(tm)* ).
Why would they? Simpler is cheaper and easier, both to manufacture and to fix.
What problem does adding cylinders solve?
I believe some early Ferraris and Lamborghinis had smaller V8s.
The jag e type V12 was about the displacement of a small block Chevy, but with 4 more cylinders.
But there is a point where the easiest power gains are by increasing displacement.
Why would they? Its expensive to make, to maintain and on top of that its a small displacement, so it makes nearly the same power as a 4 cylinder would.
The more cylinders you have, the heavier, more complex and more expensive the engine will be. Cost is a huge driving factor, especially with vehicles used like an appliance. For enthusiasts, most will want as much HP as possible, and it doesn’t cost much to increase the displacement of an engine and gain a lot of HP potential. A small bore long stroke would also be boring to drive. Like a tractor.
Short stroke engines though have very low torque figures and have to rev really high to make power. Revving high is hard on an engine and the tolerances have to be very well maintained. It’s also not the most friendly to daily driving. A typical V8 is praised for having torque down low. Remove that and it wouldn’t be that great of an engine.
You’d want something better balanced like an inline 6 so it shakes less and needs less counter balancers to be smooth, letting it rev higher more easily.
Cost, size, market, and complexity all play a role in the number of cylinders and the size of the engine. I love V10’s but they are a lot more complicated and less developed than a V8. And as someone who lives in the US the V8 is always going to sell more than any other engine.
The most efficient design seems to have settled around 500cc per piston (for a car). Smaller displacement means more surface area per volume, more heat loss relative to fuel burned.
Automotive engineer here. A few crazy answers, lots of people making the right conclusion from the wrong criteria.
Let’s start with the fundamental of setting shit on fire. When it comes to making power and torque the bottom line is everything comes down to how much oxygen you can get to burn in an engine. Burning x volume of oxygen nets you y energy. If you burn more oxygen you make more power. That’s our goal with a combustion engine. In a 1 cylinder engine or a 30 cylinder engine of the exact same displacement and the same design parameters the same energy is released by burning the same volume of oxygen.
Every moving part in an engine has friction, and every part in an engine has both a materials cost and a labor cost to make and to install in the engine. When it comes to the friction aspect you end up taking some of that energy being released by the burning oxygen and using it to overcome the friction instead of turn the engine, so you end up with less efficiency – less of the energy you’ve released is being turned into torque because some is being used up. From a pure efficiency standpoint a 1 cylinder engine will be more efficient. From a cost standpoint a 1 cylinder engine is also cheaper, of course.
So why do multi cylinder engines exist at all? The biggest reason is vibration and balance. If you need to burn say 2 liters of oxygen to get the desired power and you do that with 1 cylinder you’ve got one huge explosion happening for every two rotations of the crankshaft. If you split it up into a 2 cylinder engine of 1 liter per cylinder you’ve now split the size of each bang in half, but doubled the frequency of them to 1 per rotation of the crank. The smaller explosions result in less harsh of a bang and the force of that makes the engine vibrate less, makes the power delivery smoother, and makes it easier to design an engine that won’t destroy itself with its own forces. If you double it again and make 4 cylinders of 0.5 liter each you’ve now got 25% of the force per bang, and it’s hugely smoother, more comfortable to drive, requires less fancy engine mounts to keep the passengers happy, etc.
Now if you are trying to make more power what do you need? More burninating. We can always use a turbo or supercharger to force extra oxygen into the engine, or we can simply make the engine displacement bigger. If we want say an 8 liter engine and stick with our 4 cylinders you now have 2 liters per cylinder like we did on our previous 1 cylinder engine. Forces are huge, vibration goes up again, and the engine must be very well designed to be balanced and withstand the forces. To make things more smoother again we can stick with our 0.5 liter per cylinder format and we make a 16 cylinder engine, ala Bugatti.
You’ll find that engines tend to hover around this formula. Most 2 liter engines are a 4 cylinder. Most 3 liter engines are a 6 cylinder. 4 liters tend to be an 8 cylinder. Obviously there’s some outliers, very notable ones being American V8s that are 750cc or even more per cylinder, but most engines around the world have found 500cc per cylinder to be the magic number.
Slapping on more cylinders only serves to increase friction, reduce efficiency, and add cost. This is why you see modern engines all going to fewer cylinders and using other methods to make the required power.
The sweet spot right now is a 2.0 liter 4 cylinder, 4 valve, with variable valve timing and a turbo. Lighter, cheaper and easy to tune.
Because with turbo and superchargers you can still obtain the power of larger displacement engines with a way smaller engine while also giving you better mpg