EXPERIMENTAL INVESTIGATIONS ON EXHAUST EMISSIONS WITH AN AIR GAP INSULATED ENGINEN. Janardhan and M.V.S. Murali Krishna
Experiments were carried out to study exhaust emissions of diesel engine withair gap insulated low heat rejection (LHRâ2) combustion chamber consisting of air gap insulated piston with 3mm air gap, with Superni (an alloy of nickel) crown and air gap insulated liner with superni insert with neat diesel with varied injection timing. Exhaust emissions of particulate emissions, nitrogen oxide (NOx) levels, carbon monoxide (CO) and un-burnt hydrocarbons (UBHC) were determined at various values of brake mean effective pressure (BMEP) of the LHR-2 combustion chamberand compared with neat diesel operation on conventional engine (CE) at similar operating conditions. The optimum injection timing was found to be 31obTDC (before top dead centre) with conventional engine, while it was 29obTDC for engine with LHRâ2 combustion chamber with diesel operation. Engine with LHRâ2 combustion chamber with neat diesel operation showed increased pollution levels at manufacturerâs recommended injection timing of 27obTDC, and they improved marginally with advanced injection timing of 29obTDC in comparison with CE at 27obTDC. The exhaust emissions from diesel engine cause health hazards and also environmental disorders. Hence, controlling of these emissions in an important and urgent step.