GearHead ,In your Professional View are these Number of fire extreme, or Normal #s
Haven't seen these high of number of vehicle fires since the Pinto.
Engine compartment fires normally follow several factors, engine hygiene, fuel system design, ignition/electrical systems, dirty engines, oil leaks/combustible material/presence of organic matter, which follows hygiene closely.
Engine and engine compartment hygiene can be parts of the same issue. Oil leaks left untended and un-repaired, as the oil collects gathers dirt or cakes on from heat, creates a source of fuel as it cokes and lowers it ignition temp until combustion.
Fuel system design. The old carburetor days, we were only one backfire away from a car or car in structure fire. Leaking fuel injector to outside atmosphere rather than down intake manifold. Of course the ignition source is usually the catalytic converter. There is a great video of a liquid fuel fire ignited by an exhaust system from Argentina tanker leak on u-tube.
Ignition system. The old distributor and plug wire days. The arching that accompanied a poorly maintained ignition system would spark fires in convenient poor hygiene conditions. Leaves, grass or collected mouse nests on engine. This organic matter by constant heating and reheating cycle would lower ignition temp due to pyrolysis only needing a sufficient ignition source, jumped spark. My personal favorite a red rag and part full bottle of motor oil wedged by the battery or any convenient space.
In this engine, as you have pointed out, we have a multiple of conditions combining to create an unacceptable situation. A plastic intake manifold, polycarbonate, an EGR system that dumps a combination of exhaust soot, carbon, and raw fuel rich carbon into the intake, failure of the EGR which depending on the failure may allow raw exhaust, un-cooled, into the intake. A turbo location directly adjacent to the intake manifold to provide excess heat. Any of which if left unattended can lead to a fire situation. As you have pointed out and I firmly agree there are a couple of engine design issues present.
Some are addressed with the new engine and some are not. The DPF regeneration would be more effective and internally cleaner if FCA utilized a 7th injector vs. the late injection of fuel into the cylinder. Not addressed. The EGR change to high/low pressure system post SCR/DPF will address part of the soot equation. PCV introducing excess oil vapor into intake manifold. Not addressed. To name just a few.
jkjk I’m just hoping they come up wirh a legit fix not just watching them burn to the ground and leaving insurance companies to pay out for their negligence.