Engine design

vic008, Jul 20, 6:12pm
When headoffice say they would like a new engine of say 500 hp, and you are the designer, can you do all that on your computer, or do you design the best and say sorry, only good for 480hp. Can you design it all on your computer and say if you do what I say, engine will give x amount?Or do you design/build and then measure output?
intrade, Jul 20, 6:20pm
well its a lot more difficult .
The question is why do you ask the question= you have to give more information as to whats behind your qestion. a engine to blow up a engine for a generator a engine for a boat a engine for a car who needs to meet euro 6+ emission. it all matters.
for example vw had a prototype TDi direct injected diesel in 1977 it only went in to production in 1990 with the audi 100 tdi thats 14 years or so on R&D for that engine.
loud_37, Jul 20, 6:25pm
Its pretty easy these days to get the HP target your aiming for, budget is the biggest factor.
tamarillo, Jul 20, 6:35pm
Yes you can do it all on your computer assuming you’re a major company with facilities. My understanding is they design, run on computer simulator, then build and test.
electromic, Jul 20, 6:41pm
+1. That's what I was told too. I had very detailed specifications on engines that I had built in case someone wanted one the same. That was early 1990's on my first windows PC. I would love to be able to design it first and run it on a simulator before spending $$$ buliding it.
marte, Jul 21, 6:32am
Plus sort out the Torque and then build the transmission to suit.
budgel, Jul 21, 10:52am
I know that F1 engine designers would build a one cylinder model first to verify that it came up with the designed performance before committing to a complete engine build.
I wouldnt be surprised if manufacturers did a similar thing to ensure the computer modelling was correct.
gibbon, Jul 28, 9:08am
computer modelling is sophisticated enough these days that you can pretty much get what you design. A lot of the "dark art" of design and tuning was real-world factors that weren't able to be fully taken into account during the design phase. Oddball harmonics, heat soak, packaging concerns for different engine bays etc
richardmayes, Jul 28, 7:52pm
Fluid dynamics is very complex even when you are talking about a static object like an aircraft moving at a steady speed in a uniform 2-dimensional flow, they still do wind tunnel testing to verify the computational models.

So I doubt they can analytically model the flow of gases in and out of an all-new head design. at least not accurately enough to predict power output and efficiency performance to within a few %?

I know in the 1990s when Jaguars went from straight sixes to V8s, they built a single cylinder test unit of the new V8 as part of the design process, to make sure the design was on track and performing as it needed to.
rbd, Jul 28, 8:35pm
Engine are not designed by a "designer" that sits down at a computer and starts tapping.

They are a complex machine with decades of R&D behind them. A team of engineers and scientists will collaborate on the design, including experts in thermodynamics, combustion, production, materials, assembly, fluid dynamics, packaging, servicing, reliability, safety, legal, durability, testing, finance, electronics, control, just to name a few. And that's all before the assembled prototypes even hit a test bed.

I do know that 20 odd years ago it took Toyota around 10 years for a new engine technology to reach production from first concept.
serf407, Jul 28, 10:47pm
Mountune 600hp 2 litre turbo 4 cylinder rallycross engine., needed a custom block. Ford factory engine blocks designed for 150hp disintegrate at 600hp turbo boost pressure levels.
Constrained by the FIA rules on engine specs, so designers try to do the best with what they are squeezed into.
Designer - 3D design and stress analysis, then design to cast maker etc.
mountune interview.
https://youtu.be/hh0fKrTXuN0?t=235 Look at koenigsegg's longer doco to see the team's design processes. Koenigsegg 3 cylinder camless engine etc https://youtu.be/MsXRIEZ1qGE
budgel, Dec 15, 6:02pm
I think computer modelling has come a long way since then, but it makes sense that they would still take time to make a one-off before committing to production.