Latvian Maritime academy

4. Experimental equipment and software used to obtain performance indicators of theexperimental dieselThe following performance indicators were obtained in the course of the study: average indicatorpressure p i ; indicated efficiency i; and in-cylinder pressure p z . To evaluate the performance indicators, apiezoquartz sensor AVL was mounted on the engine cylinder head. An optical sensor of the crankshaftrotary angle and induction sensor for top dead center definition were also mounted. The sensor data wastransmitted through an amplifier system to the PCI bus of an analog-to-digital converter (ADC) where itwas registered in the Power Graph 3.2 software package [13]. Data post-processing was conducted in themathematical modules of Power Graph and MATLAB ® software. As a result, the indicated indices, theintegral and differential heat generation characteristics, were obtained.Processing of the data saved in binary files in Power Graph ® was carried out using theDieselAnalyse software package [14]. The data processing algorithm is shown in Figure 4.The DieselAnalyse software package finds the top dead center after processing input data andpressure ordinates are split into 720 values during one engine operating cycle. The average values for aset number of operating cycles (number of cycles measured for each test was optimal and equal 125according to recommendations [14]) is found, and the mean value of crankshaft rotation speed is foundfor a set number of operating cycles. Interpolation and smoothing are performed. The absolute pressure isfound, and pressure reference line correction is performed.The software obtains the array of in-cylinder pressure values in a cycle, performance indicators, thelaw of effective heat release, and rate of pressure rise. DieselAnalyse can also save the calculated data asa MATLAB ® data file for further analysis and comparison of various engine modes. Data obtained in thisway can be processed in a variety of ways through powerful mathematical and graphical abilities ofMATLAB ® .Figure 4. Algorithm of data processing5. Results and Discussion5.1. The influence of turbocharger adjustment with vaneless turbine volute on the dieselcombustion efficiency indices and ecological characteristics on the high load modeOperation mode with P e = 67.8 kW and n = 1250 rpm is characterized by the high load and lowengine speed for investigated diesel engine. It is known that the amount of air delivered into the cylinderaffects the quality of the diesel combustion efficiency. It will be also best seen in the peak torque andpower curves modes (farther described) with high load and low engine speed. The quality of thecombustion efficiency in these modes significantly deteriorates due to the insufficient air supply deliveredby the compressor stage of the commercial (non – adjustable) turbocharger to the cylinder.55