Natural Gas as a Transportation Fuel – A Cautionary Note

Natural Gas as a Transportation Fuel – A Cautionary Note

Natural Gas is currently being promoted as a domestic clean, safe, and cheaper alternative to petroleum fuels.


Some thoughts for your consideration.


Natural Gas as domestic source of energy. The US currently imports approximately 16% of its natural gas. Some comes to us by pipeline and some in the form of LNG via ship. Increasing the use of natural gas to replace petroleum fuels simply shifts our imports from one product to another.


Currently the US uses approximately 22% of our natural gas to create electricity. This is a poor use of a valuable resource for a need that has many other fuel sources available. If this was replaced by wind, solar, nuclear, and a future renewable bio-source (see previous article: The Richards Cycle) you could eliminate our imports.


Natural Gas as a clean motor fuel. Compressed Natural Gas (CNG) and Liquefied Natural Gas (LNG) both reduce certain emissions however they are not as clean as some would have us believe. If you look the whole basket of emissions that come out of the exhaust on an internal combustion engine, a 2010 Selective Catalytic Reduction (SCR) Diesel engine actually is less polluting than an equivalent CNG or LNG engine.


While I believe you can safely use CNG and LNG, it requires more training and much greater diligence on the part of drivers and operators vehicles and fueling stations. It is important to remember that it can take far longer to fuel LNG and particularly CNG fueled equipment. This long fueling cycle can lead to lack of attention and added expense in fueling equipment.


Natural Gas as cheaper alternative. Many people incorrectly try to compare a gallon of diesel to a gallon of LNG or a gallon of CNG. While the price per gallon of the LNG and CNG may appear to be cheaper, you need to consider the energy in the gallon. For example a gallon of diesel contains approximately 139,000 Btu’s of energy, while a gallon of LNG contains about 73,500 Btu’s, and CNG works to about 34,750. In short it takes about 4 times the space to store an equivalent amount of CNG as compared to diesel.


The other concerns with vehicles powered by CNG or LNG are that they are far more expensive to purchase, for example a school bus built to run on CNG can be $30,000.00 to $40,000.00 more than its diesel counterpart.



Also when you purchase a vehicle powered by CNG or LNG you locked into one supplier for all fuel system and some engine components for ever. There is virtually no secondary supplier compatibility. You limit the range and usefulness of the vehicle due to limited ability to refuel that vehicle away from its domicile. Lastly, you have to be concerned about the value of those vehicles when it comes time to trade or sell them. In many cases this limited resale market can make a used vehicle worthless.


There is an important and growing place for alternative fuel vehicles and equipment. It takes visionary leaders with long term commitment and very deep pockets to make a change to this type of equipment successful.

You can get more information on this and other fuel related subjects at: http://www.lcbamarketing.com and click on Fuel School Articles.

Please comment here and share your thoughts, ideas, and suggestions.


Diesel Doctor



Copyright 2009© - William Richards

Cetane Number – What it is and Why it’s so Important

Cetane Number – What it is and Why it’s so Important

Cooperative Fuel Research Engine (CFR)

Cetane is a measurement of a diesel fuel ignition and or combustion quality. This Cetane Number or CN is one of several components that determine the quality of diesel and biodiesel fuels. This number is used for light and middle distillate fuels. For heavy (residual) fuels Calculated Ignition Index (CII) and Calculated Carbon Aromaticity Index (CCAI) are used.

In some ways this measurement is similar to the Octane Ratings given to gasoline. In its simplest terms Cetane Number measures the delay between the start of fuel injection into the combustion chamber and the beginning of compression ignition (Auto-ignition).

In medium and high speed diesel engines (this all automotive and truck engines) fuel needs to have a CN between 38 and 55 to operate. In general the higher the CN number, the better for the engine and for emissions. However raising CN above 55 currently offers little if any benefit.

In the US the group setting the standards for CN is the American Society for Testing of Materials (ASTM) and currently the minimum is 40. While diesel engines will start and run with 40 CN fuel, they do not run as efficiently as they will at a higher number.

In Europe the European Union (EU) has systematically over several years raised the minimum from 38 to the current 51. This has allowed engine manufacturers to produce more efficient engines with lower emissions and better economy. Most fuel in the EU has a CN of 55 or even better.

Cetane Number is measured using a very expensive and arcane Cooperative Fuel Research (CFR) engine and a process that very complex.

You can also measure CN using an Ignition Quality Tester (IQT) which is somewhat less complex, but still quite costly.

There is a third measurement called Cetane Index (CI) that measures density and distillation range of the fuel and through a calculation provides a measurement. This method will calculate a reasonably accurate number for the refined diesel.

The problem is that today most diesel fuel uses additives to reach the desired Cetane Number and additives do not affect the density, thus the CI of a fuel containing additives is not accurate.

Some of you may have seen a device that looks like a battery fluid tester (a hydrometer). These devices are not capable of determining CN or CI with any accuracy.

You can raise CN by altering the refining process or through the use of Alkyl nitrates or di-tert-butyl peroxide additives. NOTE: Remember that additives do not raise CI.

Also, biodiesel, depending on the base oil from which it is derived has a natural Cetane Rating of 46 to as high as 60.

With the advent of Pilot or Multiple Pulse fuel injection, Cetane Number becomes more important than ever. The delay in auto-ignition (CN) affects the combustion timing, which has a significant effect on power output, fuel economy, and emissions.

Raising Cetane Number together with Improving Fuel Atomization is the fastest way to improve fuel economy and reduce emissions through the use of correctly formulated additives.

Please post your comments, ideas, and suggestions

More information at: http://www.lcbamarketing.com/ - Click on Fuel School Articles.

Diesel Doctor

Copyright 2009© - William Richards

Coolant Problems in 2007 and Newer Diesel Engines

Coolant Problems in 2007 and Newer Diesel Engines

The 2007 and newer medium and heavy duty engines with the new emissions devices are creating new and potentially serious problems for cooling systems in general and coolants in particular.

With cooling loads increased by as much as 30% over the previous engines we are seeing issues that must be understood and addressed by users.

As trucks have become more aerodynamic the underhood area has been reduced and airflows restricted. At the same time we have larger displacement engines often with higher horsepower density, plus EGR systems recirculating greater volumes of very hot air together with other heat producing, exhaust restricting Emissions devices.

We have seen trucks with fiberglass hoods that have warped or melted from this tremendous heat load.

All of this places more heat into the coolant, and not only more heat, but higher average temperatures.

Many of today’s coolants are excellent products, however they need more monitoring and more maintenance than ever before.

In the past many fleet experts and OEM’s would recommend an annual check of the coolant. Today these high loads can use up the additive package found in coolants in weeks rather than months. We have seen instances where coolant is properly checked and found to be in good condition, yet in less than a month it can be worthless.

We have seen coolant actually turn black, not from contamination, but simply from continuous high heat loads. Silicate drop out and gelling is more prevalent than ever before.

When this coolant begins to deteriorate the cooling system can be damaged very quickly. We are seeing radiators and heater cores that the solder has been eaten away by the coolant. We are seeing far more liner and even block cavitation problems than ever before.

As a result we have some suggestion and recommendations to try and protect your engines and cooling systems.

Check coolant with fresh Test Strips or Refractometer at every oil change or quarterly, whichever comes first. (Note: Old test strips can give inaccurate readings)

Use only fully formulated coolants from reputable sources for top-offs, and replacement. There is now a huge problem where some suppliers are purchasing used ethylene glycol from manufacturers that had used it in the manufacture of made-made fabrics. They then try to filter out the contaminants and then they use substandard additive packages to make what they claim is new antifreeze from virgin product. This is usually a poor to very poor quality product. It will look OK and a level 1 or 2 test might not show a problem. However a level 3 or 4 test done by a reputable lab will show real and potentially damaging problems.

Never top-off with just water. Coolant works best at a 50%-50% to 50%-70% mix. If it gets out of spec, it will not work properly, and can actually cause expensive damage.

In our opinion all diesel engines in medium and heavy duty applications should have coolant filters.

If you decide that have buy concentrate and mix it yourself, get a mixing system and install either a de-ionizing system for the water or use distilled water. Contaminants in some tap water can render the coolant useless. (See item 2)

You should use only the coolant recommended by the OEM. Do not mix colors especially OA (orange) and OAC (red) with anything.

If you have a failure where oil gets in the cooling system or where you have silicate drop-out or silicate gelling, you need to flush the system with an acid type cleaner and neutralizing agent. If you don’t spend the time to do this procedure, you will have continuing cooling system problems.

Use SCA additive as required to bring the coolant back to the OEM specification.

If you have a problem where you need to make the same repair over and over, get some help. Many of the old rules don’t apply anymore.

The 2010 engines are likely to be even hotter, get ready.

Ethanol/Gasohol Problems with 2 Cycle Engines

Ethanol/Gasohol Problems with 2 Cycle Engines

2 Cycle gasoline engines have new challenges when used with gas containing Ethanol.

A 2 cycle engine gets all of its internal lubrication from a special oil mixed with the gasoline. This premix of oil and gasoline can have serious problems when Ethanol is added to the gasoline. Lubricating oil normally creates a bond with the metal components of the engines. The oil molecules create a boundary layer that protects the metal and reduces friction.

When Ethanol is present it will actually get between the oil and the metal, preventing the boundary layer from forming. This results in little or no protection for the moving components, and little or no reduction in friction forcing the engine to work harder, run hotter, and often to destroy itself.

Also many small engines have plastic carburetors, fuel tanks, and other components that Ethanol can soften or dry out which will cause them to fail. Many rubber fuel lines, o-rings, gaskets, and other parts can be delaminated or turned to a gelatin like material often failing very quickly.

Storing this type of equipment with Gasohol (Ethanol blended fuel) can lead to catastrophic failure in a relatively short time.

There are a very small number of additives that can reduce the negative characteristics of Ethanol in the gas.

We recommend that everyone operating 2 cycle engines switch to a pure synthetic two cycle oil.
The synthetic oil will provide the boundary layer lubrication in spite of the Ethanol.

Please add your comments to this post.

Oxygen (O2) Sensor and Catalytic Converter Failure Problems

Oxygen (O2) Sensor and Catalytic Converter Failure Problems

Oxygen sensors (O2) used in most of today's automotive gasoline engines are failing at an ever increasing rate.

There can be one to five sensors per vehicles and having them replaced can cost a consumer $100.00 to over $300.00 each.

Also, they rarely fail together, which means a customer can have one replaced and be back next month or even next week to have another done. This can go on and on until the customer takes their business elsewhere.

This can happen in brand new vehicles with low mileage or older high mileage ones.

Vehicles such as ambulances, police cars, and service equipment that have long idle periods and or a high percentage of idle time; and vehicles used for short trips are most susceptible to these problems.

Interestingly, most of these "failed" sensors are not actually defective or even worn out. What has happened, is that a small amount Ethanol in the gasoline (gasohol) will get past the piston rings and into the motor oil.

The Ethanol with agitation and heat liberates some of the phosphorus from the motor oil. This phosphorus is vaporized and sucked into the Positive Crankcase Ventilation (PCV) system and burned in the combustion chamber. This burned phosphorus on its way out the exhaust coats the O2 sensor(s) building up in layers.

This phosphorus coating acts as a insulation causing the sensor to react slower than normal. The engine computer reads this slow reaction time as a failure of the sensor forcing its replacement.

Note: This is the same material that coats catalytic converters causing them to go "cold" or cease to function.

Replacement of the sensor(s) is not the only option. It is possible to with a properly formulated chemical additive to clean up and remove this coating (both from O2 Sensors and Catalytic Converters) with a service procedure or with a tank additive.

The danger is that 98% of the additives on the market today are not properly formulated, and these poor quality products can actually make the problem worse, by permanently damaging the sensors or converters.

Remember; a well recognized brand name is no guarantee that it is a good product. Some of the biggest names are actually the poorest products.

It is also possible that with regular treatment, you can actually prevent these problems from ever happening in the first place.

Please comment on this and any of our other posts.