Physics assignment2
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The document describes the four cycles of a gasoline engine: 1. Intake stroke - The piston draws in a fuel/air mixture through the open inlet valve. 2. Compression stroke - The inlet valve closes and the piston compresses the mixture. 3. Combustion stroke - Near the top of the compression stroke, a spark plug ignites the mixture, forcing the piston down. 4. Exhaust stroke - The exhaust valve opens and the piston expels the exhaust gases. It also lists the specific heat capacities of various substances at 25 degrees Celsius.
Physics assignment2
- 1. Edwina De Guzman III-SSC 1. Specific Heat of Elements 2. Cycles in Gasoline Engine 1. Intake Stroke - The inlet valve is opened and the fuel/air mixture is drawn in as the piston travels down. 2. Compression Stroke - The inlet valve is closed and the piston travels back up the cylinder compressing the fuel/air mixture. Just before piston reaches the top of its compression stroke a spark plug emits a spark to combust the fuel/air mixture. The number of degrees before the top its stroke is the ignition advance. When the piston is at the top of its travel it is at top dead centre (TDC). 3. Combustion Stroke - The piston is now forced down by the pressure wave of the combustion of the fuel air mixture. The engines power is derived from this stroke. 4. Exhaust Stroke - The exhaust valve is opened and the piston travels back up expelling the exhaust gases through the exhaust valve. At the top of this stroke the exhaust valve is closed. This process is then repeated. Substance Specific Heat Capacity at 25oC in J/goC H2 gas 14.267 He gas 5.300 sodium 1.23 magnesium 1.020 aluminum 0.900 potassium 0.75 sulphur 0.73 calcium 0.650 iron 0.444 nickel 0.440 zinc 0.39 copper 0.385 sand 0.290 silver 0.240 tin 0.21 lead 0.160 mercury 0.14 gold 0.129
- 2. Kesha Mae Sagaoinit III-SSC 1. Specific Heat of Different Elements 2. Cycles in Gasoline Engine 1. INTAKE: this stroke of the piston begins at top dead center. The piston descends from the top of the cylinder to the bottom of the cylinder, increasing the volume of the cylinder. A mixture of fuel and air is forced by atmospheric (or greater) pressure into the cylinder through the intake port. 2. COMPRESSION: with both intake and exhaust valves closed, the piston returns to the top of the cylinder compressing the air or fuel-air mixture into the cylinder head. 3. POWER: this is the start of the second revolution of the cycle. While the piston is close to Top Dead Centre, the compressed air–fuel mixture in a gasoline engine is ignited, by a spark plug in gasoline engines, or which ignites due to the heat generated by compression in a diesel engine. The resulting pressure from the combustion of the compressed fuel-air mixture forces the piston back down toward bottom dead centre. 4. EXHAUST: during the exhaust stroke, the piston once again returns to top dead centre while the exhaust valve is open. This action expels the spent fuel-air mixture through the exhaust valve(s). Substance Specific Heat Capacity at 25o C in J/go C H2 gas 14.267 He gas 5.300 sodium 1.23 magnesium 1.020 aluminum 0.900 potassium 0.75 sulphur 0.73 calcium 0.650 iron 0.444 nickel 0.440 zinc 0.39 copper 0.385 sand 0.290 silver 0.240 tin 0.21 lead 0.160 mercury 0.14 gold 0.129