Technical Papers

Effective CNG station maintenance can determine the success or failure of both a CNG station and the overall NGV program. However, maintenance is perhaps the most overlooked issue affecting CNG fueling stations. In many areas, there is a severe lack of experienced and qualified maintenance and repair technicians.

In this technical paper, AFVi outlines the why, what, who, when and how of utilizing a proactive CNG fueling station maintenance plan and some of the often overlooked maintenance issues.

Fleet managers and their staff are experts at writing vehicle specifications for gasoline and diesel vehicles. Natural gas vehicles (NGVs), on the other hand, are not exactly like their gasoline and diesel counterparts. NGVs have unique characteristics that fleet managers should be aware of that will help ensure successful incorporation of NGVs into the fleet.

In this technical paper, AFVi outlines four considerations unique to compressed natural gas (CNG) that will assist writing bid specifications for NGVs.

Vehicle maintenance facilities where natural gas vehicles are serviced must be modified or constructed to conform to safety requirements related to the unique properties of natural gas. These modifications must meet the basic safety requirements, but do not need to be expensive. This technical paper describes the basic modifications that need to be made in order to be in compliance with the National Fire Protection Association (NFPA), the overarching organization responsible for the codes that govern NGV maintenance facilities.

Leo Thomason is the Executive Director of Natural Gas Vehicle Institute, where he applies his more than 25 years of natural gas vehicle experience to developing and serving as the lead instructor for a variety of natural gas related training courses for fleets around the world. Leo developed and is the lead instructor for AFVi’s natural gas vehicle fuel system and fuel storage cylinder inspection training course. In this Technical Paper, Leo answers the most commonly asked questions about compressed natural gas (CNG) fuel system inspections.

Choosing a third-party operator to provide natural gas fueling can be an excellent option for fleets who don’t want the responsibility of owning or maintaining fueling equipment. However, fleets who choose this option need to understand how natural gas fueling works and must articulate your needs clearly to avoid the need for costly remediation. This, of course, requires an impartial expert who understands the subtleties of what is involved in the contractual relationship between a fuel provider and a fleet operator. Omissions or vague and uncertain provisions are usually settled in favor of the party drafting an agreement. Usually that party is the one that controls the money. AFVi highlights these contract suggestions, learned from our experience in working directly with fleets, which will save you money and headaches down the road.

A large transit agency was experiencing engine performance problems with their natural gas buses. Their contracted service technician, responsible for maintenance of the fueling station, diagnosed the problem as an engine issue. AFVi was brought in after explaining to agency management that the sealed fuel system onboard the vehicle allows gas to flow only one way, making it improbable that the oil could leak from the engine into the onboard fuel system.

The technician in question, like many working on natural gas vehicles, assumed a vehicle problem even though the majority of engine performance issues are attributable to oil carryover, which is a problem that begins at the fueling station. If the vehicle is hard to start, hesitates under acceleration, runs rough or stalls frequently, chances are the problem is with oil from the natural gas fueling station compressor carrying over into the vehicle fuel system.