wankels, diesels, two strokes? i know you will put 'em as DLC’s
i suggest inline-single, inline twins, and V-twins, that might be interesting, because “the first gasoline car ever made/Benz-Patent Motorwagen” was powered with single-cylinder engine
Game starting date will be around 1930-1940 off the top of my head so essentially there is no chance at all those will make it into the release or any expansions. There are so many more things that will be lined up ahead that it would be a long time until those are considered, however once the game is released and if the Developers allow modding( which they will i believe) feel free to have a crack at it i guess 
Remember, guys, this game is a tycoon game. They must cater to the things which almost all cars used. Thus, these engines, with such a small market shares, hold little import to the game. Also, I believe it was said it takes several months per new engine added; time which could be better put into more important things. We do not want to add things into the game which will only be useful for a couple of years. Single cylinder engines are not used today in cars; they are obsolete for that purpose. V twins are almost never used in cars, only bikes (which this is not simulating). I2’s experience the same issue. I believe the furthest they will go along this line is I3’s.
Look at the recent q&a video. Diesels are far more popular in cars than these, and killrob effectively explains why they are a low priority.
This Q&A answers all diesel and wankel related questions. Inline-2 engines would be an easy thing to add to an engine DLC pack though, single cylinders too, but then again they are not very common in proper cars 
They would not take the same implementation time as the diesels? Sorry, I was under the impression that each engine type required its own calculations. Even so, the percentile would be even lower than those diesels, I believe
Nooooo hehe all “normal” petrol 4-stroke engines can be put into the game in ~1h, what takes time is the art. Inline-2 engines have relatively small art requirements because there are not that many fuel system combinations to model. All engine types (inline, V, and boxer) are in the game, but only the ones you see so far have any art done.
Well, I guess it’s up to the artists whether or not they get implemented 
That does show the fact that the calculations you guys are using are very good though!
1: Can you write a list of the engine types coded in?
2: What percentage of time goes into the coding of an engine, and what percentage to the art?
Well, you know the list! All engines that will be in Automation 1.0 are in, but there’s no art for the ones that you don’t already have.
The engine code we’re running on doesn’t care about engine type as long as it is an I, V or B config… we could put in V32s within less than an hour for calculation only on that basis, but modeling it would take about a month, in that case probably more
To get to that point of compatibility and scalability we spent 2 years building and fine-tuning the code, so there is no clear answer to your question.
[quote=“Killrob”]Well, you know the list! All engines that will be in Automation 1.0 are in, but there’s no art for the ones that you don’t already have.
The engine code we’re running on doesn’t care about engine type as long as it is an I, V or B config… we could put in V32s within less than an hour for calculation only on that basis, but modeling it would take about a month, in that case probably more
To get to that point of compatibility and scalability we spent 2 years building and fine-tuning the code, so there is no clear answer to your question.[/quote]
If you need help, can i help you in this: I’ve made a fieldwork with 9,5/10 mark about history, technical and evolution of car, and the engine sizes (the relation bore/stroke or the configuration of pistons in the space).