I read that
Ford Taunus (not to be confused with Taurus, it was a small model for German market) used to be made with a V4 engine but that's about it. How come V4 never became more used in modern automotive engineering?
I read that
One of the most influential reason as to why the V4 didnt take off is the ROI(return on investment) . The reason as to why we have the V configuration is to save space , High performance cars have V configuration since they have upwards of 6 to 8 cylinders and putting them in a straight configuration will eat up a lot of space thus the V.
- In the V4 that advantage is not there since the size difference is very minute.
- The V4 configuration is more expensive to produce you need 2 cylinder blocks,so on and so forth.
- Inline cylinders are much much much more refined than V engines and since most 4 cylinder cars are family everyday cars refinements sits on top of requirement.
- V4 engines are harder to maintain since they have complex builds and harder to reach for components.
In summary, there is no need of a much complex V4 engine when an inline 4 can do the job much better at lower cost and higher refinement.
That said , Hondas have used the V4s on their VFR range to great success.
Edit: Lancia used V4s on the Fulvia on which the stratos is based, to great success in rallying.
tl;dr: They did. They're called Subarus.
For completion, you should remember that Subaru has had great success with the 180 degree V4 (normally called a flat-4). By using a flat engine, they avoid many of the balancing issues faced by more narrow V configurations: the pistons are opposing and the crankshaft can be slightly shorter than on an inline-4. They also allow a much lower center of gravity.
There is a space trade off: the engines are longitudinally shorter but much wider than inline engines.
There is also a trade off in terms of plumbing convenience: the flat low engine allows for much easier routing of the intake piping (as there's more space to work with above the engine) but the exhaust side requires two lengthy manifolds. This exhaust routing can make turbocharging plumbing complicated as well. For example, my engine requires an up pipe to route the exhaust energy up from the joined exhaust manifolds to the turbine side of the turbo. This is a lot of piping that is generally not required in an inline-4.
As a result of all this, the exhaust note emitted by the turbocharged flat-4 is distinctive (it sounds like you're saying "badda badda badda" rather than a steady tone). Any Subaru driver will recognize you as one of the family without even glancing up.
Besides the reasons Anarach mentions, one of the biggest reasons the V4 didn't take off is inherently, the V4 @ 60° is a rough running engine, especially at low RPM (idle & off-idle). It is very hard to balance. The V6 and V8 engines are much easier to balance, especially considering most of these are 90° V engines. Engines which are V4 @ 90° are much easier to balance, but lack in space considerations. When an engine runs rough, it is hard not only on itself, but on every other component of a vehicle as well. It does not lend to driver/passenger comfort either.
Also, in transverse engine arrangements (most front wheel drive cars), having a V4 would actually have fitment issues which you don't have with an I4 engine. With a V4 configuration, it would easily fit from side to side, but have issues front to back, which would require more space to accomplish. This would be defeating the purpose. An I4 configuration does the job just fine.
V4 engines are more complex and therefore they're more expensive to produce. Keep in mind that 4 cylinder engines are usually (but not exclusively) installed in lower-spec vehicles where price is a factor. A 16-valve V4 would require four camshafts, more engine bay room and will produce less torque than an equivalent inline 4.
The only reason 6 cylinder engines and up are in a V configuration is due to size constraints. a V6 is much shorter than an I-6. This also means that you can easily fit the V6 in a front wheel drive vehicle without having to make it wider.
Though there are still cars with inline-6 engines. Most notably the BMW 135i, 135iM, 335i and M3 (I think they're still I-6).
I4's need balance shafts to make them acceptable NVH wise in the modern market so they all have them now. The added complexity and power robbing thought to be worth the tradeoffs by every car maker in the world. I4's in cars are inevitably under square to keep the length down, large bores=more length, which tends to limit red line and ultimately performance but the fact is high rpm motors are not compatible with mass market cars. While in the past, the past 2 decades say, a maker could have adopted a short stroke V4 and sold it as a performance design none did. Now with the ubiquity of turbos, for mpg efficiency and performance. high RPM is not needed for high performance so the window on V4's in cars which has been closed has now been locked.
Note: most don't know it but Honda MotoGP bikes use a V4, as does Ducati of course. This speaks to ultra high performance aspects of V4's over I4's.
Just one correction, a 90 degree V4 is more refined than an inline 4. It has perfect primary balance. And while I agree that a transverse V4 doesn't make much sense, a longitudinal one certainly does as it puts less weight over the front axle.
While the cost is certainly more than an I4, I'm surprised that luxury manufacturers with RWD platforms, that make V8s don't use them. They would be smoother (luxurious), they mostly just have to chop the V8 in half so costs aren't as bad, and the weight balance is better.
The 90 degree V4, with proper counter weights, has primary balance. It is effectively two 90 degree vtwin engines connected to a common crank. The 60 degree V4 is not a smooth running engine and requires a balance shaft.