Development of 1.2L MPI Bi-fuel LPG Engine for Indian market application 2009-24-0119
In developing countries, the recent rise in the operating cost of gasoline passenger cars has forced vehicle / fleet owners to opt for alternative gaseous fuels like CNG and LPG. Due to non-availability of the efficient gaseous systems from OEMs, many ‘retro’ or after market kits are being used by the vehicle owners to take the advantage of the low kit cost. These after market systems pose major issues related to engine warranty, safety, emission compliance, performance, driveability and adverse effect on the main stream gasoline engine.
This paper describes the development of 1.2L, Bi-fuel (Gasoline – LPG) MPI engine for the Indian market. The objective of the project is to develop a bi-fuel LPG variant of the already existing gasoline engine without compromising on performance, driveability, safety and emissions with minimum cost impact. Precise control of LPG operation necessary to meet the engineering targets is achieved by use of EMS in master-slave architecture. The architecture uses two ECUs wherein the Gasoline (master) ECU and LPG (Slave) ECU works in tandem thereby eliminating sensor duplication and providing cost advantage. The system is completely diagnosable with automatic transition to gasoline in case of LPG system failure or empty tank.
The vehicle meets the Bharath Stage 3 norms (equivalent to Euro 3) with sufficient margin in both gasoline and LPG mode. The max power drop in LPG is 4% which is close to the theoretical value. There is no deterioration in low end and max torque with LPG.
Driveability and acceleration performance with LPG are at par with gasoline. Durability aspects specific to bi-fuel operation have been addressed by modification to the engine hardware. Compared to gasoline, the CO2, CO and HC emissions are lower by 11%, 15% and 39% respectively. In short, this MPI LPG system, offers the best of both fuels without major cost escalation and complies with the required legal safety norms.