Fuel modifiers for natural gas reciprocating engines

Abstract

Described herein are fuel modifiers for natural gas reciprocating engines, while recognizing the application of the inventions herein may be applied more broadly, to other natural gas-based engine systems. The fuel modifiers are primarily free-radical initiators, and the presence of this fuel modifier allows the engine operator to operate the engine under leaner conditions because, while employing the same ignition energy, more free-radicals are formed, thus overcoming the problems associated with dilution of the pool of free-radicals in the flame.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a divisional of U.S. Ser. No. 14 / 705,152, filed May 6, 2015, entitled “FUEL MODIFIERS FOR NATURAL GAS RECIPROCATING ENGINES”, published as US 2017 / 0009166 A1, herein incorporated by reference in their entirety.TECHNICAL FIELD OF THE INVENTION[0002]Described herein are fuel modifiers for natural gas powered reciprocating engines. The fuel modifiers described herein are free-radical initiators and are particularly suited for optical ignition (i.e. laser-spark ignition) natural gas engines. The application of suitable combustion enhancers can allow for the use of lower-powered lasers. Other advantages of fuel modifiers for enhanced combustion include the ability for lean engine operation for reduced emissions, and improved fuel efficiencies.[0003]Fuel modifiers can also reduce the engine's knock tendencies, which can increase the power density and / or improve engine efficiency. The fuel modifiers described below are also a...

AI Technical Summary

Benefits of technology

[0016]The fuel modifiers are primarily free-radical initiators, and the presence of this fuel modifier allows the engine operator to operate the engine under leaner conditions because, while employing the same ignition energy, more free-radicals are formed, thus overcoming the problems associated with dilution of the pool of free-radicals in the flame. The same principle can allow the engine operator to operate at a lower ignition energy. Altering the source of free-radical initiators can also reduce the engine's knock tendency, which can increase engine performance and efficiency.

Problems solved by technology

However, as a fuel mixture becomes leaner, the spark energy needed for combustion increases as well, and it becomes difficult to initiate a flame front.

NOx emissions from stationary natural gas engines are regulated emissions, meaning producers are either limited in the amount of NOx emissions that their engines can emit, or must pay regulatory fines if their emissions sources exceed mandated thresholds.

Further, existing spark natural gas engines are becoming increasingly expensive to maintain, as leaner operating conditions are applied.

This cost escalation is caused by the producer's need to run increasingly leaner mixtures, which reduces the cycle life of the spark plugs.

The power output of natural gas engines is limited by the amount of fuel that can be admitted before pressure waves form in the cylinder (referred to as engine knock).

This would then lead to higher engine efficiencies.

A higher peak pressure for existing spark ignition engines further reduces the cycle life of the spark plugs.

This factor increases the operating costs, for spark ignition engines.

However, laser ignition systems suffer from issues not exhibited by traditional spark systems.

Second, the high-power laser systems currently contemplated are not commercially viable as they are costly and the beams they produce are too powerful for fiber optic cable transmission.

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