Lambda Characterization of Diesel-CNG Dual Fuel Engine

India today is facing challenge of energy depletion and environmental pollution. The transport sector in India is major energy consuming sector. The dependence on liquid fuels in road transport sector is deep routed and is increasing exponentially as the number of vehicles on road is shooting up. Besides dependence on liquid oil environmental pollution is another problem which modern society is facing today. The exhaust from liquid fuel is diminishing air quality day by day which is increasing human health problems like respiratory diseases, increasing hospitalization, decreasing visibility during peak hours in Indian metros. It is therefore necessary to switch over to alternate fuels like CNG which is clean alternative fuel. CNG has clean burning properties and CNG vehicles generate fewer exhaust and greenhouse gas emissions than their gasoline or diesel powered counterparts. CNG costs about 15 to 40 % less than gasoline or diesel. CNG can be used on dedicated engine which exclusively operates on natural gas or dual fuel engine, with diesel. Dual fuel engines offer number of potential advantages like fuel flexibility, lower emissions, higher compression ratio, better efficiency and easy conversion of existing engines. In order to understand operation of diesel-CNG dual fuel engine it is necessary to study effect of CNG substitution on lambda of engine. Lambda is excess air ratio which is ratio of actual air fuel ratio to stoichiometric air fuel ratio. This paper presents lambda characterization analysis using diesel-CNG dual fuel engine. Value of lambda has been calculated for each percentage substitution of diesel by using Brettschneider equation. Lambda has been calculated from percentages of pollutants like Carbon dioxide, Carbon monoxide, Nitrogen oxides and oxygen. Computed lambda was plotted with % of substitution, speed, power and torque. Results and graphs have been discussed in paper.