Since Homogeneous Charge Compression Ignition (HCCI) has significantly low temperature combustion, NOx will be dramatically reduced while the mixture will be largely homogenous, thus soot formation will naturally be reduced too. The system can be operated under an ultra lean fuel condition thus able to achieve high efficiency and low emission. In addition to, two-stroke engines advantages i.e. light, simple construction, less components and cheap to manufacture, two-stroke engines have the potential to pack almost twice the power density than that of four-stroke engine with similar capacity. The problem of poor combustion efficiency and high white smoke emission, which is caused by burnt engine oil, can be addressed by the incorporation some features that will ultimately convert a typical two-stroke engine into an efficient HCCI engine demonstrating bulk combustion. This paper briefly described an attempt to modify two-stroke engine design to prove the claim. Such an engine with its conversion will be suitable for use as a prime mover for series Hybrid Electrical Vehicle (HEV) giving high power-to-weight ratio and improved efficiency of the overall vehicle powertrain system.
This project present an experimental test results on energy consumption of a refrigerator compressor triggered by using thermostat and programmable logic control (PLC). The PLC modulates the speeds of the compressor according to refrigeration load using inverter based on control law written in the PLC memory. The temperature setting for both thermostat and PLC were varied at-8 °C and-10 °C respectively. At-8°C the results indicate PLC consumed 4.45 to 6.79% less energy compared to thermostat setting. While at-10°C, the saving made through PLC is in the range of 6.43 to 12.88%. The fluctuation of freezer compartment is better when PLC controlled. As the energy input to compressor is lower due to the slower speed, this enhanced the coefficient of performance (COP).
The usage of electric compressor inside conventional non-electric vehicle is a new shifts in current vehicle air conditioning system which currently using belt-driven compressor to operate. The usage of belt-driven compressor causes the compressor speed to vary with engine speed rotation, which we cannot control. The usage of electric compressor to replace the belt-driven compressor makes the speed to be according to the cooling load and thus reducing engine load. The current research activity focuses on the development of electric compressor using direct current (DC) from vehicles battery to replace current belt-driven in vehicle air conditioning system. Performance study is focusing on temperature inside cabin, cooling capacity, compressor power consumption and coefficient of performance (COP). The DC compressor speed is varying at 1800, 2000, 2200, 2400, 2500 and 3000 rpm at internal heat load of 1000W with temperature set-point of 20°C. The system uses On/Off controller and compared to belt-driven compressor. The overall experimental results in better energy efficiency at the expense of lower cooling capacity.
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