Analysis of Exhaust Emissions with Low Heat Loss Diesel Engine with Alternate Fuels

Abstract

Gaseous fuel is an efficient and environmentally-friendly energy source over traditional fuels and are highly combustible and produce a lot of energy per unit volume.  It provides  a high energy density per unit volume and  little toxic by-products when combusted which reduces air pollution problems. Gaseous fuel help to reduce air pollution and greenhouse gas emissions. For these reasons, gaseous fuel is becoming increasingly popular and is likely to continue to be used more and more in the future. Biodiesel is a form of diesel fuel derived from plants, consisting of long-chain fatty acid esters. It is a renewable and clean-burning fuel that is made from waste vegetable oils, animal fats, or recycled restaurant grease for use in diesel vehicles. Biodiesel produces less toxic pollutants and greenhouse gases than petroleum diesel and it improves engine lubrication and increases engine life since it is virtually sulfur-free.The drawbacks associated with use of vegetable oils in diesel engines such as high viscosity and low volatility can be reduced to some extent by converting them into biodiesel. However, they cause combustion problems in diesel engine, due to their moderate viscosity, and hence call for low heat rejection (LHR) engine, which can burn low calorific value fuel, give high heat release rate and faster rate of combustion. The concept of ceramic coated engine is to minimize heat loss to the coolant, thereby increasing thermal efficiency. LHR engine in this investigation consisted of ceramic coated diesel engine.They are many methods to induct gaseous fuels such as port injection, carburetion technique, injection of gaseous fuel at the near end of compression stroke etc,.Investigations were carried out with biogas gas as primary fuel inducted by port injection and cottonseed biodiesel was injected into the engine in conventional manner. Particulate matter (PM), oxides of nitrogen (NOx), carbon mono oxide (CO) levels and un-burnt hydro carbons (UBHC) are the exhaust emissions from a diesel engine. They also cause environmental effects like green-house effect and global warming. Hence control of these emissions is an immediate effect and an urgent step. The pollutants of PM, NOx,CO and UBHC were determined at full load operation of the engine with varied injection timing such as recommended injection timing and optimum injection timing. NOx levels were reduced with provision of exhaust gas recirculation (EGR) at optimum flow rate of 10%. The maximum induction of biogas with conventional engine (CE) was 35% of total mass of biodiesel as full load operation, while it was 45% with ceramic coated diesel engine (LHR). Particulate emissions were determined by AVL Smoke meter, while other emissions were measured by Netel Chromatograph multi-gas analyzer at full load operation. These pollutants were drastically reduced with induction of biogas and further reduced with advanced injection timing.