A Technical Review of Compressed Natural Gas as an Alternative Fuel for Internal Combustion Engines

Abstract

Natural gas is promising alternative fuel to meet strict engine emission regulations in many countries. Compressed natural gas (CNG) has long been used in stationary engines, but the application of CNG as a transport engines fuel has been considerably advanced over the last decade by the development of lightweight high-pressure storage cylinders. Engine conversion technology is well established and suitable conversion equipment is readily available. For spark ignition engines there are two options, a bi-fuel conversion and use a dedicated to CNG engine. For compression ignition engines converted to run on natural gas, there are two main options discussed, there are dual-fuel engines and normal ignition can be initiated. Natural gas engines can operate at lean burn and stoichiometric conditions with different combustion and emission characteristics. In this paper, the CNG engines research and development fueled using CNG are highlighted to keep the output power, torque and emissions of natural gas engines comparable to their gasoline or diesel counterparts. The high activities for future CNG engines research and development to meet future CNG engines is recorded in the paper.

Bi-fuel System - Gasoline/LPG in A Used 4-Stroke Motorcycle - Fuel Injection Type

“…Such arrangement provides a back-up fuel where gaseous refuelling facilities are not well developed. Gaseous fuels have low energy density resulting in low engine performance, low engine volumetric efficiency, and need of pressurized storage vessel [14,16]. However large pressure fuel tank could be utilized but weight, space, performance and cost must be compromised.…”

“…The average power output from burning LPG over the speed range of 65-100 km/h was 5.16 hp which was about 3.9% lower than that from using gasoline91 of 5.37 hp. According to Semin et al [14][15][16][17], the performance of the converted bi-fuel engine will generally drop 15-20% in maximum power from the petrol. In general, bi-fuel modified vehicles suffer power loss and encounter drive ability problems as from the design and/or the installation of the retrofit conversion packages.…”

“…This was a fuel back-up arrangement. Typically, a gas-fuelled vehicle needs refuelling twice or three-times as often as similar petrol [14]. …”

“…To utilize the original engine arrangement system, the bi-fuel converted vehicle was fitted with fuel-injected engine modified to control the gas flow and revised ignition timing or alternatively, fitted with a standard gaseous control system [14][15][16][17]. Similarly, the motorcycle tested which was a fuel-injection type with water cooling system was fitted with the standard LPG equipment set for vehicle which was modified to control LPG firing properly.…”

Learning Equipment for the Flammability Limits of Liquefied Petroleum Gas

“…A lot of researchers contributed to the liquefied petroleum gas such as, Adzimah and Anthony (2009);Bakar (2008); Lu and Li (2011);Meshkatoddini (2008); Ning and Chan (2007).…”