Search Results

In this study, experiments were performed on a 4-stroke, 6-cylinder turbocharged, direct injection (DI) diesel engine using two oxygenated fuels blended with European auto diesel fuel (DF) to investigate the engine performance and exhaust emissions with special interest in fine particles. In the investigation, 20 vol% jatropha biodiesel was added to the DF; while 6.31 vol% diethylene glycol dimethyl ether (DGM) was added to the DF to maintain same oxygen percentage (2.26 wt%) in the blended fuels. The fuel is designated as DDGM for the DF-DGM blend and DB20 for the DF-biodiesel blend. The fine particle number was determined with a scanning mobility particle sizer (SMPS). Carbon monoxide (CO), total unburnt hydrocarbon (THC), smoke, total particulate matter (TPM) and oxides of nitrogen (NOx) were also measured.

This paper reports on experimental investigation of diesel combustion and exhaust emissions with Fischer-Tropsch (F-T) - biodiesel (BD) blended fuels. F-T fuel was used as a reference fuel for its superior properties to diesel fuel (DF). BD from non-edible jatropha oil was blended with F-T fuel. Using non-edible jatropha oil as a feed-stock, jatropha BD eliminates the food versus fuel conflict. The experimental results showed that exhaust emissions including carbon monoxide (CO), total unburnt hydrocarbon (THC), smoke, total particulate matter (TPM) and oxides of nitrogen (NOx) were reduced with F-T fuel compared to DF. CO, THC, smoke and TPM emissions were reduced significantly, while NOx emissions were somewhat higher with BD blended fuels compared to F-T fuel.

The world is looking for an alternate fuel to replace the existing petroleum based products due to the depletion of natural resources and it has been projected for future unavailability and fluctuation of oil price in an international market. The EU directive targets 20% of all fuel should be from bio-fuels by 2020. There is a need to improve performance and emission levels in Compression Ignition (CI) or Spark Ignition (SI) engines to comply with stricter automotive norms and regulations due to the global warming issues. This research work is influenced by these factors and is expected to motivate the governing bodies to implement directives with higher bio fuel blends. In this context, a four stroke, single cylinder naturally aspirated (NA) direct injection (DI) diesel engine with 8 BHP @ 1500 rpm coupled with water cooled eddy current dynamometer was used for the experiments.

A simple, low cost, cyclonic separator has been designed, fabricated and tested to separate the particulate matter from diesel engine exhaust. It has been found that within the range of design/rated rpm, efficiency of the cyclone increases with increase in torque. However the efficiency of the separator was found to decrease as the engine was run at a speed higher than the design speed. The maximum efficiency of the cyclonic separator was obtained as 85% at 1500 rpm with 28.2 N-m torque. As evident from the result, it was possible to reduce most mass of the particulate matter from the diesel exhaust under the above condition without any change in engine performance and back pressure.

In this report diesel combustion and exhaust emission with neat diesel fuel and diesel-biodiesel blends is investigated. In the investigation, first, the making of biodiesel is done by esterification and second, experiment is conducted with neat diesel fuel and diesel-biodiesel blends in a four stroke naturally aspirated (NA) direct injection (DI) diesel engine. The volumetric blending ratios of biodiesel with conventional diesel fuel are set at 0, 5, 10, 15, and 20. Compared with neat diesel fuel, diesel-biodiesel blends show lower carbon monoxide (CO), and smoke emissions due to the improved properties after esterification and the presence of oxygen in the biodiesel. With diesel-biodiesel blends nitrogen oxide (NOx) is reduced at retarded injection timing but increased at advanced injection timing. Engine noise is reduced significantly with all diesel-biodiesel blends.

The fundamental parameters related to engine combustion and performances, such as, heating value, theoretical air-fuel ratio, adiabatic flame temperature, carbon dioxide (CO2), and nitric oxide (NO) emissions, specific heat and engine thermal efficiency were investigated with computations for a wide range of oxygenated fuels. The computed results showed that almost all of the above combustion-related parameters are closely related to oxygen content in the fuels regardless of the kinds or chemical structures of oxygenated fuels. An interesting finding was that with the increase in oxygen content in the fuels NO emission decreased linearly, and the engine thermal efficiency was almost unchanged below oxygen content of 30 wt-% but gradually decreased above 30 wt-%.

Significant improvements in exhaust emissions and engine performance in an ordinary DI diesel engine were realized with highly oxygenated fuels. The smoke emissions decreased sharply and linearly with increases in oxygen content and entirely disappeared at an oxygen content of 38 wt-% even at stoichiometric conditions. The NOx, THC, and CO were almost all removed with a three-way catalyst under stoichiometric diesel combustion at both the higher and lower BMEP with the combination of EGR and a three-way catalyst. The engine output for the highly oxygenated fuels was significantly higher than that with the conventional diesel fuel due to the higher air utilization.