Turbo OM617
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- Joined
- Nov 19, 2006
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I think you need to do a little more research...
My bus fleet has both active (MY2008) and passive (MY2006) systems.
The passive systems plug with high idle time (winter) but take 45 minutes to remove the DPF, power wash the filter and get back on the road. Haven't had one crack from normal use (only a few failed when a turbo or engine fails).
The active systems frequently clog the catalyst every 500 hours of operation and burn out the DPF every summer due to the programmed mandatory active regen every 24 ECM hours (no matter the DPF soot load).
45 minutes of shop labor every few months to clean the DPF.
Vs.
45 minutes of shop labor every few months to clean the cat and $3500 to replace a melted DPF once per year.
So its actually YOU that needs to do some research. The passive systems are far less stressful on the engine and a fleet/owner's budget.
The reason they are not used anymore is difficult integration with engine management to minimize emissions.
For passive systems its relatively trivial to hollow out the cat/DPF segments and put a muffler inside so there isn't excessive noise to give up the ruse.