Electronics intervention in fuel systems of two-wheelers will become the norm to achieve emission norms such as BS 6 as well as for future regulations
The upcoming BS 6 emission norm, which is closer than ever, requires vehicles to emit lower levels of CO2 gases while making them more efficient, in terms of fuel economy. This is especially integral to the Indian automotive segment, where two-wheelers form a majority. Not only is India considered the largest two-wheeler market in the world, it is also a market that is almost completely filled with petrol engine models that are focussed towards the mass segment. The penetration of electric two-wheelers is almost insignificant at present.
Two-wheelers in the mass segment are always known to offer good fuel mileage, and this requirement will continue to drive the market, despite the requirement for lower emissions with BS 6 standards. This brings in a requirement for technologies that aid in increasing efficiency of internal combustion engines, while keeping a check on emissions. The adoption of optimal fuel supply systems that deliver an ideal level of air and fuel mixture into the engine is a key factor in balancing the performance and tailpipe emissions.
The traditional method of providing fuel to the engine has been through the mechanical system of carburettors. A carburettor contains jets that push the fuel into the combustion chambers of the engine, with the amount of fuel flow depending completely on the amount of air capable of being sucked into the system. However, the requirements of BS 6 as well as future norms limit the capability of carburettor systems to achieve the required parameters.
This has led the two-wheeler industry to move towards next-generation fuel supply systems that are infused with electronics to feed engines with the optimal fuel-to-air ratio. Electronic Fuel Injection (EFI) systems that use sensors and actuators are able to supply precisely the required amount of fuel into the engine. There are two main types of EFI systems– Throttle Body Injection (TBI) and Multi-Point Injection (MPI), with the primary system witnessing adoption in the two-wheeler segment in India due to the prominence of single-cylinder engines.
The TBI system is similar to a carburettor, where single or dual injectors located in the central throttle body supply fuel to the engine through the intake manifold. The difference is that instead of using the engine vacuum to pump fuel through metering circuits as in the case of carburettors, the fuel is sprayed into the manifold through the injectors in this system.
The fuel regulation in EFI systems is controlled by a combination of fuel pressure and injector timing, with the volume of fuel delivered depending on the amount of time the injectors are on. Similarly, fuel delivery is also increased when there is a higher pressure differential between intake vacuum and fuel line pressure, which is controlled by a fuel pressure regulator. Some of the components that make up an EFI system include idle air control valve, throttle position sensor, airflow sensor, cold start valve, warm-up regulator, fuel pressure regulator and fuel injector.
EFI systems also bring in the need for engine control units that monitor the engine constantly and relay information to ensure that the engine receives the optimal fuel supply at different conditions. Therefore, vehicle health monitoring is also another benefit that can be enabled by the adoption of EFI systems.
While the Indian market has been heavily-dependent on carburettor systems, this technology can only be deployed in low-power engines if they want to comply with stringent BS 6 regulations and those that will follow. All top OEMs are already offering BS 6-compliant vehicle models with EFI technology that are compatible with the new emission standards, and this will certainly grow further. The increased demand for these electronic fuel systems will also create economies of scale and drive down the cost of EFI technology in future, eventually making it the industry norm.