Lab 2 - Gas Engine -Internal Combustion Engine Lab Handout

Lab 2 - Gas Engine -Internal Combustion Engine Lab Handout...

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Internal Combustion Engine Full Load Peformance ME 114 Lab Handout Spring 2008 Introduction The power plant in today’s hybrid cars, such as the Toyota Prius, have an internal combustion gasoline engine, an electric generator, storage batteries, an electric drive motor, and power electronics to control the electrical power to the drive motor. The gas engine is coupled to the generator, not the mechanical drive train as in conventional cars. When the engine is charging the storage batteries, it is beneficial to adjust the engine speed and load to maximize the fuel efficiency and therefore increase the overall miles/gallon capability of the car. The fuel efficiency can be maximized when the engine output (brake horsepower or watts) is high and fuel consumption rate (kg/sec) is low. Gasoline fuel has an energy content of approximately 44,000 kJ/kg. With a 100% conversion efficiency, 1 kg fuel is equivalent to 12 kWh of electrical energy to drive the motor (equivalent to running your hair dryer for 12 hours). Mechanical engineers are familiar with the Carnot cycle efficiency as the maximum for an ideal thermodynamic cycle. For a typical internal combustion engine, the thermal efficiency is a function of engine compression ratio, air specific heat ratio, k. The maximum thermal efficiency of the 3.5 HP engine in the ME 115 lab is approximately 20% and varies with speed, load, and fuel mixture. The carburetor design establishes the fuel consumption rate; however the Cussons engine test apparatus has the ability to adjust the fuel mixture from rich (too much fuel) to lean (too little fuel). In this lab, we will keep the fuel mixture on “rich”. The fuel and air flow rates can be measured and Air Fuel Ratio (AFR) and specific fuel consumption (SFC) calculated for the mixture range. Purpose
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This note was uploaded on 09/08/2010 for the course ME 115 at San Jose State University .

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Lab 2 - Gas Engine -Internal Combustion Engine Lab Handout...

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