Influence of Combustion Chamber Design Parameters and Intake Environments on Spark Ignition Engine Performance and Exhaust Gas Emission

In the present paper, the effect of the combustion chamber design parameters on the improvement of combustion efficiency (the heat generated inside the combustion chamber) and the enhancement in the pollution rates (heat emissions) from a four-stroke, spark-ignition engine has been studied experimentally and theoretically. Two different programs, Gaseq and Ansys, were used to simulate the effect of the combustion chamber shape, turbulent kinetic energy, intake temperature, intake pressure, parity ratio, compression ratio, and engine speed on reducing specific fuel consumption in the engine, reducing carbon dioxide emissions, and increasing overall engine efficiency. The results showed increasing the intake temperature increased the amount of heat produced in the combustion chamber. This leads to increases in the overall efficiency of the engine, but leads to increasing the carbon dioxide and nitrogen oxide emissions. Increasing the intake pressure has a positive effect on the combustion temperature and pressure, but it has a negative effect on carbon dioxide and nitrogen oxides. Raising the pressure ratio improved the overall efficiency of the engine by increasing the combustion heat, but increasing specific fuel consumption and emissions. Also, increasing the engine speed above the permissible limit has an adverse effect on the spraying speed due to the piston speed being higher than the flame speed, which leads to a reduction in the engine brake torque. An increase in the compression ratio leads to higher fluid pressure and output capacity, but combustion methods occur. An increase in the kinetic energy of the turbulence leads to good combustion. A bowl in a piston has the highest rate of rotation and rotation compared to flat and hemispherical pistons. That is, the design of the cylinder head of this type leads to an improvement in the combustion efficiency and thus the efficiency of the engine.

Arm motion control model based on central pattern generator

According to the theory of Matsuoka neural oscillators and with the con- sideration of the fact that the human upper arm mainly consists of six muscles, a new kind of central pattern generator （CPG） neural network consisting of six neurons is pro- posed to regulate the contraction of the upper arm muscles. To verify effectiveness of the proposed CPG network, an arm motion control model based on the CPG is established. By adjusting the CPG parameters, we obtain the neural responses of the network, the angles of joint and hand of the model with MATLAB. The simulation results agree with the results of crank rotation experiments designed by Ohta et al., showing that the arm motion control model based on a CPG network is reasonable and effective.

Comparative Assessment of Low-Concentration Ethanol and Waste Fish Oil Biodiesel Blends on Emission Reduction and Performance Improvement in Variable Compression Ratio Engine

The costs of conventional fuels are rising on a daily basis as a result of technical limits,a misallocation of resources between demand and supply,and a shortage of conventional fuel.The use of crude oil contributes to increased environmental contamination,and as a result,there is a pressing need to investigate alternate fuel sources for car applications.Biodiesel is a renewable fuel that is derived chemically by reacting with the sources of biodiesel.The present research is based on analyzing the effect of fish oil biodiesel-ethanol blend in variable compression engine for variable compression ratio(VCR).The processed fish oil was procured and subjected to a transesterification process to convert fatty acids into methyl esters.The obtained methyl esters(biodiesel)were blended with ethanol and diesel to obtain a ternary blend.The ternary blend was tested for its stability,and a stable blend was obtained and tested in VCR engines for its performance,combustion,and emission characteristics.In the second phase,experiments are conducted in the diesel engine by fueling the fish oil methyl ester and ethanol blended with diesel fuel in the concentration of 92.5 vol%of Diesel+7.5 vol%of Fish oil+1.25vol%ethanol,92.5 vol%of Diesel+7.5 vol%of Fish oil+5 vol%ethanol,87.5 vol%of Diesel+12.5 vol%of Fish oil+1.25 vol%ethanol,87.5 vol%of Diesel+12.5 vol%of Fish oil+5 vol%ethanol,82.5 vol%of Diesel+17.5vol%of Fish oil+1.25 vol%ethanol,82.5 vol%of Diesel+17.5 vol%of Fish oil+5 vol%ethanol to find out the performance parameters and emissions.Because the alternative fuel performs better in terms of engine performance and pollution management,the percentage chosen is considered the best mix.The results showed that the use of a lower concentration of ethanol in the fish oil biodiesel blend improved the engine thermal efficiency by 5.23%at a higher compression ratio.Similarly,the engine operated with a higher compression ratio reduced the formation of HC and CO emissions,whereas the NOxand CO_(2)emissions increased with an increased proportion of biodiesel in diesel and ethanol blends.