Gasoline Engine Performance, Emissions, Vibration And Noise With Methanol-Gasoline Fuel Blends

The consumption of fossil fuels raises major issues, such as energy availability and environmental preservation. In order to minimize these issues, it is important to propose alternative fuel. Alternative fuel to be proposed should be easy to apply current type of enginethat do not require engine modification and environmentally friendly. This study aims to determine the effect of addition of methanol as a non-fossil fuel mixture into RON 88 gasoline. The ratio of mixture is 80% of RON 88 gasoline and 20% of methanol. We conducted the experiment to determine the mixture effect on fuel properties, engine performance, engine vibration, engine noise, and exhaust emissions. The engine simulation utilized the TV-1 engine (Kirloskar Oil Engines Ltd.). The results show that the engine performance of fuel mixed with methanol tends to be better even though the fuel consumption is higher, the highest specific fuel consumption in the methanol mixture is 2.9 kg/kwh while the specific fuel consumption for gasoline without a methanol mixture is 2.64 kg/kwh. The largest engine vibration occurred in the measurement of the vertical radial direction of 36 m/s2 and 34 m/s2 for with methanol and without the addition of methanol, at 1200 rpm to 1600 rpm respectively. Engine noise is higher for fuel mixed with methanol with the largest value of 86.4 dB compared to 85.7 dB for pure gasoline. Lower emission levels for fuel blended with methanol, where the highest HC emission for pure gasoline is 32 ppm while fuel mixed with methanol is 17 ppm.

Multibody analysis of the opposed-piston aircraft engine vibrations

One of the characteristic features of piston engines are vibrations caused by the pistons moving in the cylinders. During the engine design process, it is necessary to determine the level of vibration that can occur in the engine. This is especially important for aircraft engines. Due to the minimization of the weight of the aircraft, it is necessary to limit the factors that may cause damage to the structure. One of these factors is engine vibration, which can cause resonance and, consequently, a dangerous stress concentration. Long-term action of variable loads may also lead to the formation of fatigue cracks. The article presents the results of a multibody analysis of an opposed-piston diesel engine. It is a two-stroke three-cylinder aircraft engine. The engine has two crankshafts and six pistons that run opposite each other, but the rotation of the shafts is shifted in phase 14°. Engine vibration will also be caused by crankshafts which, to reduce weight, are not equipped with counterweights. The calculation results are presented in the form of time courses of forces and displacements on the engine supports and FFT analysis of the vibration velocity. The results show that the maximum vibration velocity is 7 mm/s and occurs at a frequency of 140 Hz, which corresponds to twice the rotational speed of the crankshafts. The results obtained from the tests allow for the selection of the flexible elements used in the real prototype engine supports.

Comparative assessment of engine vibration, combustion, performance and emission characteristics between single and twin-cylinder diesel engines in unifuel and dual-fuel mode

The persistent efforts among the researchers are being done to reduce emissions by the exploration of different alternative fuels. The application of alternative fuel is also found to influence engine vibration. The present study explores the potential connection between the change of the engine operating parameters and the engine vibration pattern. The objective is to analyse the effect of alternative fuel on engine vibration and performance. The experiments are performed on two different engines of single cylinder and twin-cylinder variants at the load range of 0 to 34Nm, with steps of 6.8Nm and at the constant speed of 1500rpm. The single cylinder engine, fuelled with only diesel mode, is tested at two compression ratios of 16.5 and 17.5. While, the twin-cylinder engine with a constant compression ratio of 16.5, is tested at both diesel unifuel and diesel-compressed natural gas dual-fuel modes. Further, in dual-fuel mode, tests are conducted with compressed natural gas substitutions of 40%, 60% and 80% for given loads and speed. The engine vibration signatures are measured in terms of root mean square acceleration, representing the amplitude of vibration. The combustion parameters considered are cylinder pressure, rate of pressure rise, heat release rate and ignition delay. At higher loads, the vibration amplitude increases along with the cylinder pressure. The maximum peak cylinder pressure of 95bar is found in the case of the single cylinder engine at the highest load condition that also produced a peak vibration of 3219m/s2.

Resonance Analysis and Vibration Reduction Optimization of Agricultural Machinery Frame—Taking Vegetable Precision Seeder as an Example

In order to solve the problem of vigorous vibration of agricultural machinery frames, taking a vegetable precision seeder as an example, the concept of vibration reduction was proposed. The modal analysis of the frame was carried out, and the accuracy of the finite element model was verified by comparing the modal test of multipoint input and multipoint output (MIMO) and simulation results. Additionally, the main frequency of engine vibration was the main excitation source of frame resonance. According to the modal shapes, it was proposed to increase the fixed beam structure and to carry out simulation tests. The time-domain signal of the maximum deformation position in the first-order vibration mode was measured, and the vibration spectrum analysis maps before and after optimization were obtained by Fourier transform. A field experiment showed that the seeding quality of the whole machine was significantly improved after optimization. This study provides a reference for the analysis of vibration characteristics and the vibration reduction design of the agricultural machinery equipment.

Vibration fault identification of a turbojet engine based on cepstrum analysis

A vibration fault identification method based on vibration state characteristics of a turbojet engine and cepstrum analysis technology was proposed in this paper, and the application of cepstrum in vibration analysis of an aero-engine was also discussed. The vibration data of the turbojet engine in three different test cases of 0.8 rated state, max power state, and afterburning state were analyzed using the cepstrum analysis method. The periodic components and the characteristics of multi-component side-frequency complex signals in the dense overtone vibration signals were separated and extracted, which reflected the sensitivity of the positions of the compressor casing and the turbine casing to the harmonic vibration components of high- and low-pressure rotors and the characteristic difference of different vibration parts. Thus, effective identification of vibration faults was achieved. The results shows that the cepstrum analysis technique applied to the vibration analysis of the turbojet engine can better identify the sideband components of the frequency domain modulated signal and enhance the recognition capability of the fault frequency component, which is helpful to identify the engine vibration fault quickly and accurately.

Engine Fault Detection Approach Based on Angle Domain Signal Model

Engine vibration signals include strong noise and non-stationary signals. By the time domain signal processing approach, it is hard to extract the failure features of engine vibration signals, so it is hard to identify engine failures. For improving the success rate of engine failure detection, an engine angle domain vibration signal model is established and an engine fault detection approach based on the signal model is proposed. The angle domain signal model reveals the modulation feature of the engine angular signal. The engine fault diagnosis approach based on the angle domain signal model involves equal angle sampling and envelope analysis of engine vibration signals. The engine bench test verifies the effectiveness of the engine fault diagnosis approach based on the angle domain signal model. In addition, this approach indicates a new path of engine fault diagnosis and detection.

Method for synthesis of an intelligent automatic system for diagnosing combustion engine vibration of the power supply system of an unmanned vessel

The paper considers the implementation prospects and features of the synthesis of an intelligent automatic system for diagnosing the internal combustion engine vibration of a power supply system in terms of developing technologies for automatic or remote control of unmanned vessels. The paper addresses the issue of predicting the technical condition of a combustion engine using available diagnostic methods. The study focuses on the equipment required for monitoring and analyzing the technical condition of the engine of an unmanned vessel when operating in automatic or remotely controlled mode. An algorithm has been developed for collecting, storing and accumulating data on the condition of the engine components and units in the on-board information system of the vessel to exchange data on the condition of the engine and its components during remote monitoring and to determine fault codes. The approaches to the synthesis of an intelligent automatic system for diagnosing the combustion engine vibration are considered from a methodological point of view. Vibration diagnostics equipment used for the analysis of the technical condition of the engine is proposed. Some results of the classification of the technical condition of the engine are presented. The expediency of introducing and using hybrid intelligent systems based on artificial neural networks is exemplified by diagnostics of the MITSUBISHI S16R engine.