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Development works with metallic open channel PM Filter Catalyst in conjunction with diesel oxidation catalysts and Pre Turbo Catalyst (PTC) on Diesel Cars and Commercial Vehicles with CRDi engines have been reported earlier. These results show that PM conversion efficiency of the order of 40 % can be achieved with PM Filter Catalyst on passenger car diesel engines with continuous regeneration capability. Recently experiments were carried out on a DI engine having distributor type rotary fuel injection equipment with electronic control, turbocharged and inter-cooled, calibrated for BS-III (EURO-III) emissions, with an aim to explore the potential of oxidation catalyst and the PM Filter Catalyst to meet BS-IV (Euro-IV) emission norms. These experiments were carried out with 500ppm sulphur diesel. The results of the tests are presented in this paper. It is seen that with only an oxicat of low level catalyst loading, PM (soluble organic fraction) can be brought down by 20%.

Metallic Catalytic Converters employ alternate layers of flat and corrugated metal foils. To impart higher efficiencies to metallic catalytic converters, there have been progressive developments in the area of foil structures. The constructional details as well as performance behaviour of some of these structures have been reported earlier for automobile applications. In this paper the details of these new structures and the catalyst performance improvement applied to smaller size 2/3 wheeled vehicles are discussed. Transversal Foil Structures (TS) earlier studied and experimented for automobiles have shown improved catalytic performance. Analysis was made for two representative sizes of TS Structure applicable for 2/3 wheelers. It is seen that TS structure improves catalytic converter performance for smaller sizes also. This improvement can be utilized to reduce the Catalytic Converter volume and catalyst loading for same performance as compared to regular substrate.

Catalyst in the exhaust system of Light -duty diesel vehicles operating at low temperatures typical of urban driving does not reach light-off temperature. There are options in metallic substrates for close-couple operations for optimum heat utilization to effect higher temperature for oxicat performance and for efficient operation and regeneration of metallic particulate filter, which by itself is an attractive option for EU IV Norm. The present paper gives an account of developments in this field. Also the paper gives an insight into the developments of new innovative metal foil structures for use in petrol and diesel vehicles, which provides enhanced catalytic efficiencies without increasing cell densities.

Exhaust emission and fuel consumption of a vehicle is influenced by its usage, operating conditions, traffic conditions as well as the individual behaviour of the driver. A study on the actual operating conditions for city buses has been carried out for Delhi city under a Government sponsored Project by The Automotive Research Association of India (ARAI). A bus operating on the normal city route was selected and equipped with sensors and data acquisition systems to record the vehicle parameters such as vehicle speed, distance, time, gear shifting pattern, engine speed, temperatures and other variables every second. The data collection exercise was carried out on six selected routes covering lean, average and peak periods of traffic and vehicle density. Earlier experience shows that data thus collected can be synthesised to fall into statistical repetitive driving sequences. This averaged data is converted into a most logical driving pattern or cycle for buses operating in Delhi city.

To improve the performance and durability of two stroke engines, pressure, volume and temperature of crankcase are the important parameters which need optimisation. The paper investigates these scavenge parameters of a small two stroke engine with a view to alleviate its thermal conditions. Investigation of the pressure histories have been done with reference to pressure fluctuations, backflow, Kadenacy effect, list approximation, ring sticking, engine seizure, crankcase volume, crankcase temperature, cylinder barrel temperature, engine speed and physical parameters of the engine. By reducing the crankcase volume by 11 %, the maximum torque has increased by 11 % and shifted from 3000 RPM to 4000 RPM. The maximum power at 6000 RPM has increased by 12 %. Crankcase volume of 2 to 2.5 times the cylinder displacement is considered to be suitable.

Two carburetted passenger cars of different makes, converted for CNG (Compressed Natural Gas) operation (in dual mode) and optimised by ARAI (The Automotive Research Association of India, Pune, India), were tested for vehicular performance. The respective engines were also mapped for performance, energy consumption and emission. The power loss in CNG mode was 7% & 15% and torque reduction was 21% & 15% in respective engines. There is considerable improvement in thermal efficiency and reduction of emission in the entire operating range. The vehicle performance on Chassis Dynamometer shows similar results. The second engine was also tested with a ceramic catalytic converter which gave 93% reduction in CO and 50% reduction in HC in major portion of operating range. 1100 CC car was also tested on the test track. Optimisation work included installation of ARAI mixer design.

The paper describe investigations on the vibration characteristics of a gasoline engine due to piston slap and a diesel engine due to combustion. Engine parameters and vibration data were recorded and time series signals were obtained. The effect of speed, load and other engine parameters on vibration is investigated. Vibration due to piston slap is analysed with reference to major-minor thrust relationship, cylinder to cylinder variation, piston-slap force diagram and vibration-frequency curves. The experimental results suggest that all reciprocating engines would exhibit a complex vibration pattern due to piston slap at harmonic series of discrete frequencies, and the reason for this is analysed. The vibration transmitted by engine structure in response to the in-cylinder pressure development is termed here as ‘Vibration due to Combustion’ and is assessed from the spectrum of the Combustion Pressure curves and their derivatives in terms of time.