The potentials of retrofitting existing motorcycles with an aftermarket EFI system to suppress exhaust emissions at higher road speeds

Abstract

There are over 150 million motorcycles being used worldwide, with more than 65 million in ASEAN region alone. With the continuous increase in living costs, carburetted motorcycles are becoming more popular. However, these carburetted engines are well known for its low-operating efficiency, high fuel consumption and high level of hazardous emissions, namely carbon monoxide (CO) and unburned hydrocarbons (HC). Therefore, stringent emissions regulation, such as EURO 4, is in place, which requires 4-stroke engines to operate using efficient electronic fuel injection (EFI) system with an on-board diagnostic (OBD) tool, supported by appropriate exhaust after-treatment system. Nevertheless, the enforcement of this regulation is only applicable for newer motorcycles models. Normally, the lifespan of carburetted 110 – 250cc engines can go beyond seven years. Hence, retrofitting them with aftermarket technologies will be one of the options to reduce the overall pollutants release to the environment. In this paper, the presented work was aimed to determine the feasibility of a commercially available EFI kit (branded FGKTM) to reduce the CO and HC emissions coming from a carburetted 150cc petrol-fuelled engines. The FGK kit was installed on the test engine by replacing the existing carburettor through a plug and play approach with a tuneable ECU. This ECU was tuned using dedicated tuning software to produce combustions that would emit the lowest CO and HC emissions. Testing using a chassis dynamometer and comparing with carburetted engines, at road speeds of 70 km/hr, 80km/hr to 90 km/hr, showed significant reduction of CO (between 82% - 87%) and HC (between 36% to 47%); based on brake specific emissions values. These findings showed the potentials of retrofitting existing carburetted engines in reducing the mass of emissions and could also benefit existing motorcycles and small petrol-fuelled manufacturers that are still relying on carburettor system.