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Particulates from diesel engine consisting of particles of carbon, sulphates, oil, fuel and water are measured by filtering a sample diluted in a partial or full flow tunnel according to strict standards and weighing them. However, these methods suffer from high initial and running costs. On the other hand, filter-smoke-meters measure the light reflected from a filter paper through which a known volume of exhaust gas is passed and opacity meters measure light absorbed by a standard column of exhaust. They measure visible black smoke easily at reasonable expenditure. Today, these simple instruments are highly developed to control measurement noise, resolution and repeatability, and can be used to estimate carbon soot precisely.

Particulates from diesel engine consisting of particles of carbon, sulphates, oil, fuel and water are measured by filtering a sample diluted in a partial or full flow tunnel according to strict standards and weighing them. However, these methods suffer from high initial and running costs. On the other hand, filter smoke meters measure the light reflected from a filter paper through which a known volume of exhaust gas is passed and opacity meters measure light absorbed by a standard column of exhaust. They measure visible black smoke easily at reasonable expenditure. Today, these simple instruments are highly developed to control measurement noise, resolution and repeatability, and can be used to estimate carbon soot precisely.

The design and development of a new four-stroke two-cylinder diesel engine family of 1.29 litre capacity for off road are discussed. The engine is in naturally aspirated and turbocharged and intercooled versions and rated from 11.9 kW/1500 rpm to 25.7 kW/2500 rpm. The engines were tuned for air and fuel flows, air utilisation, fuel air mixing, performance and emissions at steady state at a development lab and later certified in national labs. The high altitude capability of the TCIC was checked using a model. The engines rated at less than 19 kW satisfy India Generator set and off road norms of India and Europe equivalent to USTier4 standard, and at higher ratings, standard equivalent to US Tier4-interim. In the second part of the paper, the design of coolant and oil pumps, oil cooler for TCIC engine and the piston with steel oil control ring are discussed. The higher loaded TCIC engines use fillet hardened crankshafts of chromium molybdenum steel.

The passby noise is the net effect of the noise from the engine, tires, vehicle panels, the fan and the exhaust silencer. Exhaust noise is probably the loudest component of the passby noise in diesel trucks. The passby noise is measured when the vehicle is in transient condition according to the standards. A technique is developed to simulate the transient noise from the exhaust using 1-d simulation software AVL-Boost. It considers thermodynamics of combustion in the engine including the turbocharger, inertia of the engine and the vehicle. The technique helps in optimizing exhaust silencer, acceleration and in-cylinder parameters in transient conditions and the turbocharger fatigue. A 165 kW 6-cylinder turbocharged and intercooled engine is simulated. The transient performance of the engine in the vehicle is validated by comparing the predicted results with the observed fuel consumption on road, time to accelerate to 60 km h−1 and the fluctuations in the turbocharger speed.

Field trials are carried out on diesel engines operating in tropical conditions at higher dust levels, temperature, humidity and load factor than the European and North American conditions. Passenger buses and trucks with engines of sump capacity 0.061-0.110 litre/hp and SAE15W40 viscosity oil meeting API CG-4+, API CH-4, API CI-4 from Group-I and Group-II base stocks are considered. Results show that the CH-4 oil is best suited for the subject engines. Oil drain interval is found proportional to the sump volume for the same stress on oil. Group-II base oil performed better than Group-I in limiting TAN and controlling oil consumption. Cost effective oil with a TBN of eight is sufficient with low-sulphur fuels without affecting oil drain interval. Iron concentration and kinematic viscosity decide useful oil life with respect to the limits fixed by the engine manufacturer. Oil life is found to be higher for passenger buses than trucks.

Parameters like brake mean effective pressure, mean velocity of the piston, hardness of the wear surface, oil film thickness, and surface areas of critical wear parts are similar for all the diesel engines. The mean piston velocity at the rated speed is nearly the same for all the diesel engines. The mechanical efficiency normalized to an arbitrary brake mean effective pressure (bmep) is dependent on the size of the engine. The engine life seems to be proportional directly to the square of a characteristic dimension namely, cylinder bore of the engine and inversely to speed and load factor for engines varying widely in sizes and ratings.

A robust and cost-effective off-road engine that is economical for backhoe application is developed to meet the Indian BS-III CEV (construction equipment vehicle) standards equivalent to the US Tier-3 emissions regulation for markets where (a) advanced maintenance facilities are not available in remote areas of operation, (b) availability of the right fuel is not fully assured, (c) the initial cost of the engine is under tight control and (d) the legendary fuel economy of direct-injection diesel engines is not traded off when migrating to higher emissions standards. The highlights of the layout of the 4-cylinder 3.8-liter 56 kW diesel engine are the use of a high-pressure exhaust gas recirculation (EGR) and a proven inline mechanical fuel injection equipment that is easy to maintain and tolerant to inferior quality of fuels used inadvertently in remote areas of operation. Use of 25% EGR reduces oxides of nitrogen (NOx) formation inside the combustion chamber by 30%.

To uprate a 6-Cylinder In-line engine from 123 kW to 165 kW in power and upgrade the emission from Euro-2 to Euro-3 it was required to go for higher peak-firing pressures (PFP). The capability of Engine's Crankshaft to withstand the PFP was increased from 125 bar to 150 bar, maintaining the same cylinder centre distance. A crank-train model was used to achieve the required crankshaft strength for infinite fatigue life. The three aspects of crankshaft design, namely, crank strength, bearing selection, journal-pin lubrication and torsional vibration were considered during the design stage. The strength to withstand 150 bar PFP was achieved by increasing the crank web-thickness. To maintain the same cylinder centre distance, crankpin and main-journal lengths were reduced. Increased throw stiffness was achieved by increasing the crankpin diameter to improve crankshaft torsional behaviour.

Emission norms are introduced to limit exhaust pollutants from vehicular engines to improve and control ambient air quality. Thermodynamic simulation results showed the possibility of upgradation from Euro-2 to Euro-3 emission norms using a low pressure inline fuel injection pump. Geometric parameters of piston bowl, injection nozzle were adjusted and the combustion parameters like swirl start of injection, controlled injection and jet penetration were fine tuned to achieve the emission norms using the cost effective inline fuel injection pump. This fuel injection system is tolerant to indifferent fuel quality as it is lubricated by engine oil and the clearances within the pump do not demand exceptional lubricity or cleanliness of the fuel. The exhaust is polished off soluble organic fractions, carbon monoxide and hydrocarbons using a lightly loaded diesel oxidation catalyst that is tolerant to 500 ppm sulphur in fuel. Data from 20 engines showed emission is consistent.

To uprate from 90 kW to 135 kW in power and upgrade the emission from Euro-II to Euro-V a base 6-cylinder naturally aspirated engine was turbocharged and after-cooled, and the fuelling method was changed from Carburetion to Multi-Point Fuel Injection (MPFI). EGR is allowed to flow from the exhaust manifold to the inlet of the compressor. The EGR flow controlled by fixed orifice was used to limit thermal loading of turbocharger. The thermodynamic model was used to optimize the ignition timing and predict the engine performance over the operating range of speed and load while allowing stoichiometric combustion. Optimum turbocharger, diameter of the EGR-pipe and the throttle body size were selected based on thermodynamic simulation. The 3-way catalytic converter and the silencer at the turbine outlet were also simulated. The real engine was developed based on the simulation and the engine performance.