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Navistar Partners With Clean Air Power on Natural Gas Dual-Fuel Option for MaxxForce 13 Engines

Navistar, Inc. has signed a concept development agreement with UK-based Clean Air Power Ltd. to develop Navistar’s MaxxForce 13 big bore engine to run on natural gas and diesel fuel for the North American market.

The program will utilize Clean Air Power’s Dual-Fuel combustion technology (earlier post) to deliver a MaxxForce 13 Advanced EGR engine that is fully compliant with the US Environmental Protection Agency’s (EPA) 2010 on-highway diesel emissions, without the use of liquid-urea SCR (selective catalytic reduction). Upon successful concept development, the two companies will move forward to product development and validation.

Negotiations were underway for two years, according to Clean Air Power, during which time Navistar evaluated a number of different environmental technologies. Clean Air Power will spend approximately $1.5m on developing the concept over the next 10 months. During this time, in preparation for production and the next stage of development, Navistar and Clean Air Power will together seek US grant funding for full production.

As we assess changing market conditions, the ability to offer customers choice is important not only in our US markets, but in our global markets as well. As we develop this product for our International brand truck customers, we will also be able to leverage the technology in other markets and products as appropriate.

—Eric Tech, president, Navistar Engine Group

MaxxForce 13 natural gas engines utilizing Clean Air Power’s Dual-Fuel combustion technology will initially target the regional haul tractor market with a goal of a achieving a 400-mile range.

Clean Air Power’s Dual-Fuel application enables diesel engines to operate primarily on up to 85-90% natural gas with diesel pilot ignition. The Dual-Fuel technology is fitted onto a standard diesel engine, enabling a measured quantity of natural gas to be mixed with the air just before it enters the cylinder and compressed to the same levels as the diesel engine to maintain efficiency. The Dual-Fuel engine uses a small injection of diesel fuel, around 10% of the total energy of the fuel, to ignite the main charge of gas and air.

Clean Air Power is developing a next-generation version of Dual-Fuel technology it calls MicroPilot. MicroPilot is based on the use of smaller diesel pilot injections representing 1-2% of the total fuel to reduce NOx emissions by more than 80%, while also reducing CO2 emissions.

The MicroPilot engine produces the low emissions characteristic of a spark-ignited lean-burn natural gas engine, but retaining the high efficiency and power density of a diesel engine. With recent advances in diesel fuel injection technology, the Directors of Clean Air Power believe that MicroPilot could be applied to heavy-duty engines within the 2010 deadline. Clean Air Power intends MicroPilot engines to be compliant with Euro V and beyond, taking the Dual-Fuel solution into the next decade.

In January, Volvo Powertrain signed a Letter of Intent with Clean Air Power Ltd. to incorporate Clean Air Power’s Dual-Fuel technology into Volvo Truck engines. (Earlier post.)



Nat gas + diesel sounds like a very good thing.

It could be an easy way to reduce diesel pollution in cities without throwing the bus fleet out - as long as you have somewhere to put the gas tanks (like on the roof of a single decker bus).

+ for longer run trucks and buses, just use gas and keep down the diesel imports.

Henry Gibson

There is a company that makes large amounts of natural gas(methane) and several other products including fertilizers from coal in North Dakota. It pipes and sells much of its CO2 production to Canadian oilfields for production of oil improvements about 200 miles away. Low grade coal is used from a local mine. It should have also included the facilities for the production of gasoline. Long haul trucks and railroad locomotives should all have the option of adding butane, propane, ethane or methane to its fuel mix where available. There is enough weight capacity on railroads to operate most locomotives for most of their trips on methane with one to ten percent pilot fuel. The methane is used with just as high an efficiency as the diesel is. All automobiles should be built with diesel engines and the ability to run a few tens of miles at least on some form of natural gas. It is very easy and quick to make natural gas at home. We will continue to invent methods that make engine exhaust gases very clean. Humans and their pets breath out CO2 and H20 and other gases. Plug in hybrid cars are the main answer to fuel consumption in private automobiles but natural gas is a partial answer too. ..HG..


A local company has been doing this for years;


The single cylinder diesel ~30hp being developed for the Nano would be a good conversion to natural gas dual fuel as would VW's 2 cylinder TDI.

A small diesel and electric motor would make a very interesting hybrid vehicle

Roger Pham

This is a very good development. Run heavy-duty vehicles on NG or biomethane, and save on petroleum import. More solar panels and wind turbines to reduce usage of NG for electrical generation.


90% NG and 10% diesel would be cleaner. They would fill up with NG every day and the large diesel tanks would last quite a while. At 4 mpg big rigs take almost 40% of our liquid road fuel. This would reduce imported oil a bit for sure.

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