Announcement

Collapse
No announcement yet.

Coalescent filter housings

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Coalescent filter housings

    Part 2 Technical Information (click here for part 1)

    Oil as a liquid and or aerosol travel from the vehicles CNG tank through the NGV fuel lines system to the coalescent filter housing. There are two types of filter housings. One for Bi-fuel vehicles and one for dedicated vehicles. Pictures of both types of housing are included in this post.

    Bi-Fuel Coalescent Filter Housing (see picture): CNG flows from the outside of the filter element to the inside. Particles collect in the element, while the clean CNG exits through the outlet port. Liquid oil streams into the filter housing and settles to the bottom of the lower housing (filter bowl) where it collects in the sump. By design, some of the vaporized or aerosol oil passes through the filter. This pass-through oil helps to lubricate the valves and seals in the engine. Interestingly, the BQ series coalescent filter elements used in the Ford Bi-Fuel vehicles from Parker Hannifin are considered a particulate filter and not a true “coalescing” filter. They still catch the oil, just not as well as the CLS-112-6 filters used in the dedicated vehicles. The second and most significant problem relating to carryover oil originates inside the filter housing. When oil fills the sump and comes into contact with the coalescing element, excessive carry over oil is drawn through the filter and begins traveling through the system towards the compuvalve and engine. This excessive carryover oil collects in the compuvalve and injectors where it will damage the compuvalve and clog the injectors. The heat from the engine turns the oil into a type of varnish. Using Fords PM-5 injector cleaner to flush the CNG lines for dedicated vehicles and Isopropyl alcohol for bi-fuel vehicles helps break down this varnish. This is the type of housing on the Bi-fuel 1996 through 2003 Ford F-Series Trucks, Bi-fuel 1996 through 2003 Ford E-Series Vans, and some of the Contours.

    Dedicated Coalescent Filter Housing (see picture): CNG flows from the inside of the filter element to the outside. Coalesced liquid (water and oil) collects in the bowl where it is drained, while clean CNG exits the housing through the outlet port. Particulate contaminants are captured and held in the media. Liquid oil streams through the filter and into the lower filter housing. This housing does not include a false bottom or sump. The molded plastic cross top at the bottom of the filter serves the same purpose as a sump. Oil can collect around the molded bottom without being drawn through the filter. By design, some of the vaporized or aerosol oil passes through the filter. This pass-through oil helps to lubricate the valves and seals in the engine. The second and most significant problem relating to carryover oil originates inside the filter housing. When oil fills above the molded plastic bottom and comes into contact with the coalescing element, excessive carry over oil is drawn through the filter and begins traveling through the system towards the engine. The heat from the engine turns the oil into a type of varnish. This excessive carryover oil collects in the injectors. Using Fords PM-5 injector cleaner to flush the CNG lines for dedicated vehicles and Isopropyl alcohol for bi-fuel vehicles helps break down this varnish. If the problem is not corrected the oil will clog the fuel injectors and plug up the catalytic converter.

    Both the CLS112-6 Grade 6 coalescing element and the CLS112-10 Grad 10 coalescing element fit inside this housing. They are identical in appearance; the only designation being that the number "6" or "grade 6" or number "10" or "grade 10" is printed on the filter. The CLS112-6 has a coalescing efficiency of 99.97% for particles 0.3 to 0.6 Microns in size. The CLS112-6 has a maximum oil carryover of 0.008 PPM w/w The CLS112-10 has a coalescing efficiency of 95% for particles 0.3 to 0.6 Microns in size. The CLS112-10 has a maximum Oil Carryover of 0.85 PPM w/w.

    What this means in the real world: Ford specifies the CLS112-6 as the only compatible filter for the Dedicated Crown Victoria. I believe the reason for this is that the crown Victoria performs best with the lower 0.008 PPM carryover oil rate and the higher 99.97% particulate filtration. Ford specifies both the CLS112-6 and the CLS112-10 as compatible filter elements for the 1996 to 2003 Dedicated F-Series Trucks and E-Series vans. Apparently the trucks and vans are more robust and can handle the higher 0.85 PPM w/w carryover oil rate and lower 95% particulate filtration. Personally I would only use the CLS112-6 Grade 6 in the Crown Victoria. I suspect that a portion of the excessive carry over oil problems described in the Ford TSB Bulletin 03206 “Drivability – Dedicated Compressed Natural Gas (CNG) Vehicles - 4.6L and 5.4L Engine” occur because many Crown Victoria owners are unknowingly running the CLS112-10. Most people dealer & individual alike do not know the difference. This is why I only sell the CLS112-6 filters in Part 1 of this article.

    The Crown Victoria Rough Idle Drivability TSB Bulletin "TSB_03206_CrownVicCNG.pdf" under the "Attached files" listed below.
    Attached Files
    Last edited by NGXV; 07-15-2009, 01:53 AM.
Working...
X