2023 Prius Tail pipe carbon

Dusty carbon? Can you explain further? If you mean carbon buildup on the tailpipe, it could mean the engine is not reaching operating temp when running. That can happen if you only take short trips. Have you taken it to the dealer and asked them about it.

 

Odds are very good it's normal.

 

No it's not an issue. Like Mendal Leisk said, it's normal.

 

Hydrocarbon emission is normal during cold-engine running. Try to reduce short trips. With my Prius Prime PHEV, I never turn the engine on for short trips but use the BEV mode instead.

 

If you don't want to see carbon residue in the tailpipe, buy something with an exhaust particle filter.

 

They are only for direct-injection engines, which produce soot even with a warm engine. They are costly to maintain and require a special expensive low-ash (low-SAPS) Euro (ACEA) oil to reduce clogging. They are uncommon in the US.

https://360.lubrizol.com/2015/GDI-Soot-A-New-Challenge

 

The Gen 5 Prii, both regular hybrid and Prime, now have the M20A-FXS engine which has dual injection (both port and direct) and so shouldn't suffer from most of the direct injection maladies, including tailpipe soot. Some soot is normal so I doubt what you're seeing on yours is abnormal.

 

Ah, @Ansari, I knew about the Camry dual direct/port-injection engine but didn't realize that the new Prius used that engine.

In that case, yes, the soot is a result of direct injection and not a cold-engine thing.

As far as know, the main reason for the added port injection is to prevent intake-valve deposits (IVD), which are a common headache in GDI engines, as the carbon deposits left on the intake valves by the PCV oil mist are not cleaned by gasoline otherwise. These deposits further increase with lower-quality (inferior base oil, less solvency ingredients, inferior formulation, etc.) and higher-ash (higher metal content) oils. So, there is still gasoline coming through port injection to clean the intake valves thanks to dual injection, and therefore, IVD should not be a problem in this engine.

 

All engines produce particles. Even port injected. Some of which even exceeded the particle limits that put exhaust filters on diesels. Otherwise there would be no carbon build up on tailpipes.

The finer particles coming out of gasoline engines are worse for health, as they can get deeper into the lungs.

 

Perhaps, but the main concern is diesel and GDI engines as the article explains.

 

When the US and Europe implemented particle emission limits on passenger cars, there were port injected gasoline models that exceeded those limits. The industry had convinced regulators that it wasn't a concern, so gas cars were exempt while diesels needed a filter. Direct injection leads to increased particle emissions for gas. The EU does now have a particle emission requirement for gas cars, but were had been pushing back the implementation for years. Gas cars are still exempt in the US.

 

Of course all ICEs pollute. Nevertheless, it is well-known and documented that soot is especially a concern in GDI and diesel engines. That is why some GDI engines get a particulate filter.

Attacking GDI-engine particulate emissions—SAE

 

The fact all engines emit particles is why the OP has soot in the tailpipe. Build up outside it would be a concern.

Want see a clean tailpipe, find the car with the working exhaust filter.

 

I had a bike with twin exhausts; one was always sootier than the other, drove me nuts.

 

Except, if you read the SAE article I linked, it says that GDI engines produce up to ten times more soot than PFI engines—night and day.

There are no cars sold with GDI particulate filters in the US. Those cars also require a special low-SAPS ACEA (Euro) oil.