A student is setting up an experiment to investigate the mechanical and thermal performance of a single-cylinder, four-stroke diesel engine. The experimental setup consists of: (1) A fuel tank mounted on a digital balance to measure fuel mass, along with a stopwatch. (2) Pressure and volume sensors inside the engine cylinder connected to a computerised data-logging system. (3) A brake dynamometer attached to the output shaft of the engine to apply a load and measure torque. (4) A digital tachometer to measure the rotational speed of the output shaft. During a steady-state test run at a constant load and throttle setting, the student records several measurements. Describe how the student should determine the following five quantities for the engine: 1. Input power (rate of fuel energy supply), 2. Indicated power, 3. Brake power, 4. Indicated thermal efficiency, 5. Mechanical efficiency. In your answer, you should: describe the direct measurements that must be taken from the apparatus, and explain how these measurements, along with any necessary constants or reference data, are used to perform the calculations.
29 exam-style questions on AQA A Level Physics Thermodynamics and engines (A-level only), covering First law of thermodynamics (A-level only), Non-flow processes (A-level only), The $p$ - $V$ diagram (A-level only), Engine cycles (A-level only), Second Law and engines (A-level only), and Reversed heat engines (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.