While we are at this, I would like to double down on another thing DI is seemingly missing VS it’s real life counterpart.
A substantial bump to maintenance costs. DI engines have a very real problem with valve coking, BMW and VAG have been dealing with it since the 2000’s by having customers pay for an expensive (600USD-1000USD) walnut blasting process which cleans the fresh air side of the intake valves.
Toyota, and some manufactures are now running dual injection, and have both DI, and MPFI on the same engine. (See GT-86/BRZ) and this design policy is gaining traction and will be commonplace on ICE engines in a few years, as Port injections main advantage is that fuel is an excellent solvent and is keeping the fresh air side of the intake valves clean.
I propose that while we are re-calibrating DI, perhaps we should increase it’s service costs as well, and perhaps even consider adding DI/PI combo to late game (Not needed if we aren’t going to run the simulation past 2020 of course)
IN short: DI should see a service cost increase to reflect how it actually works IRL, as it requires a considerabal re-design of the PCV system to slow the process, but so long as an EGR, or VVT system is used, it will be impossible to negate the problem with out a dedicated port injection system
Example of problem below: I can attest as a Direct Injection engine owner, this IS a problem, I have already cleaned my valves with only a paltry 20,000 miles on the vehicle. I have been considering running water injection to help prevent this in the future.
(Picture is not mine, just a good example found online of the problem DI is having in normal useage)
