Thermodynamic analysis of working process effective indicators of a diesel engine with an open and closed crankcase ventilation system

Introduction (problem statement and relevance). This article provides up-to-date information analysis of the crankcase gases bypass effect from the crankcase ventilation system to the compression ignition engine intake. The paper considers the information on the variants of the crankcase ventilation systems of modern engines. The article reveals the necessity to analyze the engine working process at the design and development stage of a closed crankcase ventilation system. The legislative requirements for the implementation of the ventilation system to ensure safe environmental performance have been indicated. The purpose of the study was to assess both open and closed ventilation system effect on the crankcase space indicators, in particular, on the average specific fuel consumption, with reference to a high-performance automobile engine with compression ignition.Methodology and research methods. Theoretical and computational studies were carried out with the help of mathematical statistics and thermodynamics methods in a one-dimensional setting. The verification of the calculations reliability was carried out by comparing the simulation data and the results the internal combustion engine experimental studies.Scientific novelty and results. A thermodynamic model of a high-performance automobile engine compression ignition V8 CHN 12/13 with an open and closed ventilation system of the crankcase space has been developed. The model made it possible to evaluate the effect of crankcase gases bypass back to the engine cylinder intake.Practical significance. The developed thermodynamic models confirmed the insignificant effect on the working process of the V8 CHN 12/13 engine by bypassing crankcase gases back to the cylinder inlet.

Design and Research of Carbon Deposition Device Based on Detecting and Cleaning Gasoline Engine Cylinder

When checking and cleaning whether there is carbon deposit in the cylinder of gasoline engine, it is often time-consuming and laborious, and the process is complicated. Once the disassembly and assembly is not in place, its service life will be affected. When cleaning with carburizing agent and cleaning agent, it is difficult to fully contact with the cylinder wall, so the cleaning effect is poor and it is easy to leave its chemical composition in the engine. In this paper, some common ways of engine cylinder cleaning are studied, and a device for detecting and cleaning carbon deposition in gasoline engine cylinder is designed. The purpose is to provide a new convenient, simple and practical method for detecting and cleaning carbon deposition in automobile engine cylinder in the current market.

Evaluation on the Performance of Automobile Engine Using Air Injection Nozzle in the Intake Manifold

In the present study, a nozzle was used to improve the flow performance of an intake manifold, and its effects on the automobile engine output and the exhaust gas were experimentally studied. It was found that the engine output of a vehicle with a mileage of 30,000 km increased by 4.7% and 6.5% when nozzles with diameters of 5 and 2.5 mm were used. In addition, the engine output of a vehicle with a mileage of 180,000 km increased by 3.3% and 13.3% when nozzles with diameters of 5 and 2.5 mm were used compared to those of the same vehicle when no nozzle was used. Thus, using a nozzle for the inflow of outside air created a uniform combustion environment to improve the engine output and reduce harmful exhaust gases, such as hydrocarbon, carbon monoxide, and nitrogen oxides, by generating vortexes inside the intake manifold and increasing the degree of mixing. Furthermore, the smaller nozzle with a diameter of 2.5 mm had greater effects.

Effect of Heat Treatment on Microstructure and Dimensional Stability of Y-Modified AlSi7Cu3Mg Alloy

The application of rare earth modified AlSi7Cu3Mg alloy in automobile engine and motor casing has increased. The dimensional stability of this alloy is an important feature. In this paper, the effects of yttrium addition and different heat treatment on the microstructure and dimensional thermal stability of AlSi7Cu3Mg alloy were studied by OM, SEM and dimensional measurement. Research shows that: The dimensional stability of AiSi7Cu3Mg alloy after T6 heat treatment is better than that after T4 heat treatment, and the dimensional stability after T7 heat treatment is the best. The addition of rare earth Y can improve the dimensional stability of AiSi7Cu3Mg alloy.

An Adaptive Noise Reduction Method Based on Improved Dislocation Superposition Method for Abnormal Noise Fault Component of Automotive Engine

The acoustic signal generated by mechanical motion contains the information of its motion state, but when the signal-to-noise ratio (SNR) is low, the accuracy of real-time monitoring mechanical motion state by the acoustic signal is low. This study proposes an adaptive noise reduction method based on the dislocation superposition method (DSM), which can realize the adaptive noise reduction and the extraction of fault a component from the automobile engine abnormal noise signal of low SNR. Firstly, the wavelet coefficients of engine abnormal noise signal are obtained by continuous wavelet transform (CWT), and the fault feature points of the abnormal noise signal in each period are extracted by setting hard threshold function, window function, and feature points extraction algorithm. Then, the signal segments containing fault components are obtained by using the position of feature points to extend the length of the fault component forward and backward, respectively, and Pearson’s correlation is calculated by traversal to determine the starting superposition point of each signal segment containing fault components. Finally, the signal segments of the odd group and even group are selected for superposition calculation. When the superposition stop condition is not satisfied, the number of superpositions increased until the stop condition is satisfied, and the superposition signal can be used as a fault component. The experimental results show that, compared with the improved DSM, this method has a good effect on the noise reduction and extraction of fault components of automobile engine cylinder knocking fault, and the effectiveness of this method is verified. This method is used to reduce the noise and extract the fault components of automobile engine cylinder missing fault and knock fault, and good results are obtained.

Surface Roughness Evaluation of the Inner Surface of Automobile Engine Bores by RANSAC and the Least Squares Method

Analysis methods for plateau surfaces have been described in the ISO standards, JIS, and previous studies. The authors of a previous study proposed a method based on the concept of random sample consensus (RANSAC). This method achieved high analysis accuracy for plateau surfaces by setting detailed conditions. However, the process of setting optimal conditions is performed manually, which reduces productivity due to the manpower and man-hours required. In this study, we propose a new method for automating the setting of conditions. This method, which does not require human intervention, is expected to contribute to the improvement of productivity at production sites.