What you should know about using natural gas vehicles
Will I get the same fuel economy and vehicle performance?
Contrary to popular opinion, methane carries more British Thermal Units (BTUs) than gasoline. The energy content of gasoline depends on the season and oxygenated fuel additives such as methyl tert-butyl ether (MBTE) [used to increase the oxygen levels] that reduce emissions.
BTU Levels for Gasoline
- 114,500 for a summer gallon of gasoline without additives
- 112,500 for a winter gallon of gasoline without additives
- 112,000 for summer blends with MTBE
- 110.210 for summer blends with ethanol
- 112.210 for winter blends with ethanol
BTU Levels for Natural Gas
- 114,000 all year
BTU Levels for Diesel
- 129,500
The clear winner and most expensive is diesel with 129,500 BTUs. Because gas stations don’t have to advertise that they’re using a 10% ethanol blend in their gasoline, most don’t; however, most stations dispense this mix.
What is the difference between dedicated and converted vehicles?
dedicated vehicles
- It works with 100% natural gas
- Depends on CNG service stations
- Can’t shut off fuel if it’s overheating
- Expensive engine reconfigurations to deal with zero lubricants and high heat levels
- High maintenance costs
- Reduced torque and hp
- reduced mileage
- High conversion costs
converted vehicles
- Runs on gasoline or natural gas
- Works with a mixture of diesel + natural gas
- Double the driving range
- Change fuel while driving with the flick of a switch
- Start with gasoline or diesel to lubricate the engine and then switch to natural gas
- Low maintenance costs
- Higher torque and HP
- higher mileage
- Low conversion costs
What is the difference between aspirated and direct injection CNG kits?
- Aspirate: These systems are first generation simple technology. Vacuum kits typically cost less as they are relatively simple and easy to install. They have a closed-loop controller that receives feedback from an oxygen sensor to keep the vehicle running optimally. The performance of these systems is limited because the air intake must be reduced for them to work properly. Also, aspirated CNG kits tend to trigger the “Check Engine” light, which is a common thing. This application is intended for older vehicles with a carburetor.
- Direct injection. These systems are the leaders in CNG Conversion Kit technology. They use a powerful microprocessor that supports the built-in automatic correction and calibration system. Because these systems are designed with advanced electronics and provide vastly superior performance, they will cost more than aspirated kits. They have evolved significantly in recent years. The latest technology in these systems uses extensive electronic sensors, injectors, and a 32-bit computer that integrates with the vehicle’s computer. This provides the best fuel economy and performance. A “Check Engine” light is not acceptable with these installations.
Are there special maintenance needs for vehicles converted to CNG?
Natural gas engines work essentially the same way as gasoline engines. An air-fuel mixture is injected into the intake manifold, drawn into the combustion chamber, and then ignited by a spark plug. Most engine service requirements are very similar and can be handled by a dealer, auto shop, or trained mechanic. If an upgrade repair is needed, such as a faulty injector or loose compression fittings, these will be taken care of by the installer.
Do conversions increase my maintenance costs?
Converted vehicles require less maintenance and HALF the normal oil and filter changes. The use of CNG maintains the viscosity of the oil, which causes less wear on various parts of the engine, such as the pistons, valves and the walls of the head. The gases burn more efficiently and do not emit harmful or dirty carbon deposits which keep your oil cleaner. The use of CNG also extends the life of the engine to a great extent due to the containment of the oil film that accumulates on the cylinder walls. This containment prevents the oil from being transported to other parts of the engine, unlike engines that run on gasoline or diesel.
conversion kits
- Gasoline to CNG conversion kits run on 100% gasoline or 100% natural gas (bi-fuel to CNG conversions). A CNG tank is added to contain the natural gas. The addition of another fuel tank doubles the range. Dual-fuel conversions greatly reduce fuel and maintenance costs. Because the fuel is completely burned, your engine stays much cleaner. These conversions also reduce oil and filter changes. Cleaner burning fuel extends the life of your cars and trucks.
- Diesel CNG conversion kits combine a mixture of diesel and natural gas, dual fuel. This greatly reduces the consumption of expensive diesel fuel. Expect an increase in your mileage and a reduction in maintenance for costly oil and filter changes. The air/natural gas mixture is denser. This denser, higher octane blend creates more power and higher torque. Cleaner burning fuel extends the life of your trucks and buses.
Vehicle Benefits
Trucks and cars that run on CNG
- Natural gas carries higher BTU levels than gasoline (125 vs. 90) due to the ethanol and oxygenated fuel additives in gasoline.
- Reduces fuel and maintenance costs approx. 40%.
- Combustion without self-ignition and protects your engine from knocking, even in engines with higher levels of compression and efficiency.
- It burns 100% due to a proper mixture of air and natural gas at room temperature.
- The oil that lubricates the engine is less contaminated and reduces oil and filter changes by half.
- There is no sediment and the spark plugs stay clean. The oil on the walls of the engine cylinders is not washed off.
- Combustion gases are not corrosive. By not damaging metals, the useful life of the exhaust pipe and silencers is greater.
- The gaseous nature of the fuel eliminates cylinder scanning actions during periods of rapid acceleration, with the advantage of reducing corrosion of metal surfaces.
- The engine exhibits great performance flexibility during acceleration without jerkiness or backfiring, even at low direct speed.
- Converted vehicles can switch from using CNG to gasoline by simply pressing a button while driving.
- The CNG gasoline bi-fuel system doubles the driving range of the car.
- CNG conversions run smoother and quieter.
- The vehicles operate on all terrains, even through mountains. For example, a truck with a load of 37 tons exceeded 4,800 meters in the Peruvian Andes in May 2008.
- CNG works well under any weather conditions. As the fuel does not freeze or at low temperatures, the vehicle will always be ready to be used.
- System is fully reversible and can be transferred to other vehicles after inspection
Three main components for a vehicle conversion
- CNG conversion kits
- CNG tanks
- NFPA-52 Certified High Pressure Parts
The CNG tank can be mounted in various places. The most popular locations are in the trunk or bed of the truck. A high-pressure fuel line routes the methane through a filter and then to the engine department. The newly installed 2-stage regulator will reduce high pressure to ambient levels closer to 36 PSI. Added noise reduction injectors will dispense the gas. This process is controlled by the system’s ECU which is programmed to distribute the natural gas to match the original fuel map of the car or truck. Sensors and computers adjust the fuel and air mixture for maximum performance. CNG conversion kits do not reduce the performance of your car or truck.
Refueling at CNG stations is like refueling with gasoline or diesel and takes the same amount of time. The two tanks will double your driving range. You still need to use gasoline, as this is necessary to start, lubricate and warm up the vehicle. CNG conversion kits are programmed to protect against excessive heat and sudden changes in driving conditions. If you need to brake hard, accelerate suddenly, or drive up a steep hill, your fuel system will automatically switch to gasoline for the extra power needed.
Converted vehicles work just like the original. Adding the new fuel system is completely non-invasive and easy to reverse. Sequential port injection systems from trusted manufacturers do not alter or interfere with any of the original engine manufacturer (OEM) factory settings or fuel system, nor do they tamper with any engine controls or devices. Because there is no tampering, there is no violation of anti-tampering laws.