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Dual Fuel System Displaces 87% of Diesel with Natural Gas

A fuel consumption test demonstrated the ability of US Energy’s Hybrid Fuel System to replace more than 87% of diesel with natural gas.

The vehicle used for the consumption test was a GM C190 Colorado Pickup using an Isuzu 2.5-liter engine. The vehicle route was a 162-mile trip. In a diesel mode, the 162 miles used a total of 16.029 gallons of diesel fuel. In a dual fuel mode, the vehicle consumed 1.97 gallons of diesel fuel.

US Energy is engaged in a program with GM-Thailand to provide dual fuel system for their C190 Colorado Pickup for model years 2007, 2008 and 2009.

The Company received its first international letter of credit relating to the sale of its Hybrid Fuel System in Asia. This letter of credit is put in place to cover the delivery of the first 15 systems earmarked for a taxi company with over 3,800 vehicles.



This is pretty interesting if realistic.
a: What would it cost
b: Where / how do you store the gas without taking too much space
c: How many types of vehicles can it do ?

You could run a gas rich mixture in town and (if required) a diesel rich mixture in rural areas.
You could use a smaller gas tank to avoid using too much space in the vehicle and have diesel if you need the range unexpectedly.

Max Reid

Current CNG vehicles store gas at only 200 bar and the technology may raise it to 700 bar which means CNG vehicles will have the same range as Diesel with similar size tank.

LNG is also fast growing fuel. Soon, Gas may grab some share from Oil.


10mpg from a diesel colorado? a colorado is a small truck so that mpg sounds low, even for a truck. I would think a gasoline colorado would do better than 10mpg.


Most heavy duty compression-ignited NG engines are already dual-fuel engines. They use NG as the main fuel with diesel as a pilot fuel (<10%) for ignition. NG won't compression ignite readily on its own, thus the use of diesel pilot injection.

Also, NG is liquid at pressures necessary for diesel direct injection, so the injection equipment is ferociously expensive and complex. With a dual fuel system, NG can be premixed in the intake air, so low pressure injection equipment can be used.

Take a look at Detroit Diesel's dual fuel engines. They're widely used in California for buses.

Reality Czech
NG is liquid at pressures necessary for diesel direct injection
Methane is not a liquid at any temperature above its critical point (-82.7°C).
With a dual fuel system, NG can be premixed in the intake air, so low pressure injection equipment can be used.
Methane also dilutes the intake air charge and reduces volumetric efficiency.  Direct-cylinder injection allows the cylinder to fill completely with air before fuel is added, increasing the air charge and maximum power.
Arnold Garnsey

reality czech,
Interesting area, I can see what you are saying about methane however the subject here is NG rather than LNG read: CNG
So the size and pressure ratings are something of a worry, but nowhere near the problem of LNG.
I expect that as the cng leaves the generic lpg style mixer, there will be cooling of the air and expansion of the gas . But the net effect will be an increase in the charge desity by virtue the aspirated air is the major component and its density is increased as the heat is removed to further expand the gas.
Epecially as it is aspirated rather than injected. My reference states : Octane rating 130.
In the recent past(I Hope) lpg, ng, etc have been flamed off as ther has been no market. Lets hope the market can respond quickly to put these wastes to work.


Something is up with those numbers. That truck should be getting 2-3 times better fuel economy. A diesel colorado isn't available in the states but for comparison I drove a 3/4 ton chevy silverado with the 6.6 liter duramax diesel on a 180 mile trip. I got well over 20 mpg on the highway. So this smaller truck should get 30 plus on the highway.


It looks to me like this test was probably done with kilometers and for distance and liters of fuel and someone forgot to convert the liters to gallons.
This would put the mileage up to nearly 40 mpg.


very interesting topic

we have done diesel dual fuel system, but using LPG.
based on out test, diesel engine with turbo charger, LPG can replace around 70% of diesel fuel. increasing more LPG can result detonation..
and diesel engine without turbo charger, LPG can only replace about 30%. too many LPG injected to air intake result too rich fuel ratio
anyway, SFC for both engine with and without turbo charger decrease about 20%


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