Kindly help me in knowing the answer for this simple question. I wanted to know the reason for conducting experiments on engines as well as on turbines at constant load and at constant speed. we know that both are performance tests what is that we get from both the tests
Conducting experiments on engines by giving certain load is mostly to see the torque. It does not always in constant load and speed. Many cases it is done by giving different load to see the performance of the engine itself. We can see also the fuel consumption with different scenarios.
Steady state measurement of engine performance is surely not representative of what any engine experiences during its operating life. But it is the easiest way to make a picture of engine performance. The typical approach on engine mapping has been based on steady state maps and some map corrections for transient.
The engine tuning require the transient performance to be analysed and specific maps have to be determined to be sure the performance of the engine is correct once it is running in a vehicle.
A typical approach on top of the steady state measurement is to control engine performance in ramps of different speed (rpm versus time). These ramps should be representative of typical gradients the engine experiences in different gears.
This is a preliminary tuning of the transient behaviour and typically local enrichment is added for a good transient response. If a more sophisticated dyno is available it is the possible to fully simulate specific manouvres for a better mapping on the engine.
It is possible to measure emissions in conventional driving cycles and simulate lap time for motorsport applications.
But at the very end the steady state map of the engine is already a very good base for preliminary development, to perform comparison of experimental variants, to measure in a more precise and repetitive way engine parameters that can give an important feedback to designer and development engineers.
Not just to say 'the simplest the better' but to remark the the best starting point should be simple, especially when you need to evaluate a complete new design.
Actually the function of a engine as a mobile driver (automotive) and as a stationary driver. As a mobile driver, the engine is operated on variable speed, while as a stationary driver, engine is operated on constant speed. Testing the performance of the engine is done to determine the amount of performance in accordance with the designation, which is variable speed for mobile driver and constant speed for stationary driver. General engine performance tests include power, torque, bmep, thermal efficiency and specific fuel consumption and gaseous emissions. In stationary engines are usually equipped by the governor's mechanism to adjust the fuel consumption on the load changes so that the rotation is constant.
So performance testing is done to get the performance parameters according to the designation.
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