State Key Laboratory of Engines

Tianjin, China

State Key Laboratory of Engines

Tianjin, China
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Ge M.,State Key Laboratory of Engines | Liang X.,State Key Laboratory of Engines | Yu H.,State Key Laboratory of Engines | Wang Y.,State Key Laboratory of Engines | Zhang H.,State Key Laboratory of Engines
SAE Technical Papers | Year: 2017

Spray impacting on a lube oil film with a finite thickness is a common phenomenon in IC engines and plays a critical role in the fuel-air mixture process and combustion. With the use of early injection strategy to achieve HCCI combustion mode in diesel engines, this phenomenon becomes more and more prominent. In addition, oxygenated fuels such as methanol and ethanol are regarded as alternative fuel and additives to improve the overall performance of HCCI engine. Therefore, a better understanding about the role of lube oil film thickness in methanol-diesel and ethanol-diesel blended fuels spray/wall impingement is helpful for accumulating experimental data to establish a more accurate spray/wall impingement model and optimize the combustion in HCCI engines. In this paper, the effect of lube oil film thickness on the characteristics of spray/wall impingement of different fuels are investigated in a constant volume bomb test system. Fuels include diesel, methanol (20v%)-diesel (80v%) blended fuels(M20),ethanol(20v%)-diesel(80v%) blended fuels(E20). With the novel measurement methods, the information about film thickness and adhered fuel ratio was obtained. In general, the results demonstrate that the initial lube oil film influence the wall film distribution after impingement. With the increase of initial lube oil film thickness, the diffusion and merge interaction between spray droplets and oil film become obvious which intensify the phenomenon of the dilution of oil film. But due to the low-density and high-volatile property of M20 and E20 fuels compared to diesel, the level of diffusion and merge interaction between alcohol-diesel blended fuels spray and lube oil film is lower than that of diesel which means using alcohol-diesel blended fuels can mitigate the problem of lube oil dilution and local rich mixture during spray/wall impingement process. Copyright © 2017 SAE International.

Wang Y.,Tianjin University | Liang X.,State Key Laboratory of Engines | Sun X.,Tianjin University | Yu H.,Tianjin University | Liu X.,Tianjin University
SAE Technical Papers | Year: 2017

In this paper, the influences of metallic content of lubricating oils on diesel particles were investigated. Three lubricating oils with different levels of metallic content were used in a 2.22 Liter, two cylinders, four stroke, and direct injection diesel engine. 4.0 wt. % and 8 wt. % antioxidant and corrosion inhibitor (T202) were added into baseline lubricating oil to improve the performance respectively. Primary particle diameter distributions and particle nanostructure were compared and analyzed by Transmission Electron Microscope. The graphitization degrees of diesel particles from different lubricating oils were analyzed by Raman spectroscopy. Conclusions drawn from the experiments indicate that the metallic content increases the primary particles diameter at 1600 rpm and 2200 rpm. The primary particles diameter ranges from 5 nm to 65 nm and the distribution conformed to Gaussian distribution. Besides, particles from high metallic content lubricating oils show same chain-like and branch-like cluster and core-shell nanostructure with particles from the baseline lubricating oil. The layer fringe length and tortuosity were used to quantify the particle nanostructure. The analysis results of particle nanostructure show that metallic content leads to shorter fringes with higher tortuosity. As to the graphitization degree, four curves (D1, D3, D4, G) were used to fit the Raman spectrum curves. And the area ratio of D1 band to G band increased when the high metallic content lubricating oil was used at 1600 rpm and 2200 rpm, which means that metallic content leads to the disordered particle structure. Copyright © 2017 SAE International.

Liang X.,State Key Laboratory of Engines | Wang Y.,State Key Laboratory of Engines | Huang S.,China North Engine Research Institute | Yang G.,China North Engine Research Institute | And 2 more authors.
SAE Technical Papers | Year: 2017

Due to the mechanical forces under static conditions, the engine cylinders cross section will not be a round circle any more once they are installed. The deformation of an engine cylinder causes increasing lubricating oil consumption and abnormal wear, resulting in worse fuel economy and emissions. However, prediction of deformation on a liner has not been made because of the complication of conditions and structure. In this study, a V6-type engine body model was built and meshed with Hypermesh suit software. Then, cylinder deformation under static condition has been simulated and analyzed. First of all, experimental work was done to verify the engine model. Basically, few parameters like pre-tightened force, structure and distribution of bolts have been investigated to figure out how the cylinder bore deformation behaves via finite element analysis. Also, a simple Matlab program was developed to process the data. Specifically, Fourier decomposition has been used to find out the typical style of cylinder deformation. The results show that under static condition, the level of pre-tightened force is one of the most important factors. Furthermore, longer length of the bolt reduces the cylinder distortion due to changing the depth distribution of forces, and symmetrically distributed bolts lead to the lowest bore deformation. The Fourier program results indicate that the most typical cylinder deformation styles are the 2nd-order and the 4th-order. Among all of those deformation styles, the 2nd-order dominates and orders higher than 8 do not contribute too much to the total deformation. Based on this study, optimizing the static conditions will be helpful to protect the cylinder from distorting and wearing. Copyright © 2017 SAE International.

Jiang J.,Xi'an Jiaotong University | Wu Z.,Tianjin University | Wu Z.,State Key Laboratory of Engines
International Journal of Bifurcation and Chaos | Year: 2010

In this paper, the linear and nonlinear modes of the unforced coupled rotor/stator system from a general rotor/stator model, which accounts for both the dynamics of the rotor and the stator as well as the friction and the deformation at the contact surfaces, are derived. The bifurcations of the nonlinear normal modes are analyzed based on the constrained bifurcation theory with the linear normal modes as the constraints. Then, the existence boundaries and the backward whirl frequencies of dry friction backward whirl a hazardous self-excited oscillation in rotor/stator systems of this model are derived. It is found by analysis that many inherent characteristics of the dry friction backward whirl can be derived from the information of the interaction of the linear and the nonlinear normal modes of the coupled rotor/stator system, such as the number of existence regions and their position relationship, the minimal friction on the contact surfaces that may induce the self-excited oscillation, the upper limits of the backward whirl frequencies of the response, and more. This study has well demonstrated the dominant role of the interaction of the linear and the nonlinear normal modes in deciding the characteristics of some nonlinear dynamical behaviors. © 2010 World Scientific Publishing Company.

He W.,Tianjin University | He W.,State Key Laboratory of Engines | Wang S.,Tianjin University | Wang S.,State Key Laboratory of Engines | And 3 more authors.
Energy | Year: 2015

This paper presents an advanced mathematical model of a thermoelectric generator that includes the effect of the temperature gradient in the flow direction. The parameters of the exhaust gas from an engine may fluctuate during engine operation; thus, the influence of this fluctuation in the exhaust gas parameters on the optimal thermoelectric performance was considered with the objective of maximizing the total power output through the aid of Fortran. The optimum module areas corresponding to the maximum power output were found to be greatly affected by the flow rate of the exhaust gas but not by the gas temperature. The effect of the fluctuation in exhaust gas parameters on the performance of the corresponding thermoelectric generator at the maximum power output was also studied. A power deviation analysis method was introduced in order to design the optimal TEG module area for a high power output. Based on the results, the optimal design areas were 0.22 m2 for the co-flow and 0.3 m2 for the counterflow. The counterflow arrangement is recommended because it maintains a smaller deviation from the peak power output than a co-flow arrangement at their respective optimal design areas if there is sufficient system space. © 2015 Elsevier Ltd.

Shu G.-Q.,State Key Laboratory of Engines | Yu G.,State Key Laboratory of Engines | Tian H.,State Key Laboratory of Engines | Wei H.,State Key Laboratory of Engines | Liang X.,Tianjin University
SAE Technical Papers | Year: 2013

A bottoming waste-heat-recovery (WHR) model based on the Organic Rankine Cycle (ORC) is proposed to recover waste heat from exhaust gas and jacket water of a typical diesel engine (DE). The ORC model is detailed built based upon real structural and functional parameters of each component, and is able to precisely reflect the working process of the experimental ORC system constructed in lab. The DE is firstly tested to reveal its energy balance and the features of waste heat. The bottoming ORC is then simulated based on experimental data from the DE bench test using R245fa and R601a as working fluid. Thermodynamic evaluations are done on key parameters like waste heat recovered, expansion power, pump power loss and system efficiency. Results indicate that maximum expansion power and efficiency of the ORC are up to 18.8kW and 9.6%. Influences of engine condition, fluid mass flow and evaporating pressure on system performance are analyzed and meaningful regularities are revealed. The combined system of DE and bottoming ORC (DE-ORC) is also investigated. The results showed that the integration of the bottoming ORC greatly changed energy distribution of the DE, and the DE thermal efficiency is up to 47.2%, increasing by 9.0%. Copyright © 2013 SAE International.

Tian H.,State Key Laboratory of Engines | Wang W.,State Key Laboratory of Engines | Shu G.-Q.,State Key Laboratory of Engines | Liang X.,State Key Laboratory of Engines | Wei H.,State Key Laboratory of Engines
SAE Technical Papers | Year: 2016

Power lithium-ion battery is the core component of electric vehicles and hybrid electric vehicles (EVs and HEVs). Thermal management at different operating conditions affects the life, security and stability of lithium-ion battery pack. In this paper, a one-dimensional, multiscale, electrochemical-thermal coupled model was applied and perfected for a flat-plate-battery pack. The model is capable of predicting thermal and electrochemical behaviors of battery. To provide more guidance for the selection of thermal management, temperature evolutions and distributions in the battery pack at various ambient temperatures, discharge rates and thermal radiation coefficients were simulated based on six types of thermal management (adiabatic, natural convection, air cooling, liquid cooling, phase change material cooling, isothermal). It can be concluded that thermal radiation has little effect on temperature rise, but it cannot be ignored with increasing depth of discharge (DOD) and discharge rate. How to make the battery operate in optimum working temperature (OWT) region under various working conditions was analyzed in details. Furthermore, the differences of temperature distributions in spatial and temporal scales under various operating conditions were discussed and presented, and some constructive suggestions also were proposed for further studies. Temporal temperature distribution changes more intensely especially in the center of the battery pack, and it is more susceptible to the ambient temperature. These changes are repeated in different locations under the situation that lower discharge rates but better cooling effects. However, changes of spatial temperature distribution are monotonic, and its magnitude mainly depends on the cooling effects. Copyright © 2016 SAE International.

Liang X.,State Key Laboratory of Engines | Yang K.,State Key Laboratory of Engines | Shu G.-Q.,State Key Laboratory of Engines | Dong L.,State Key Laboratory of Engines | And 2 more authors.
SAE Technical Papers | Year: 2012

Cepstrum analysis method is an important part in the area of modern signal processing subject, which has a good application in noise source identification. The paper uses cepstrum method to analyze noise and vibration signals of diesel engine, separates and extracts periodic source signals with characteristic of non-harmonic order from complex spectrum waveform, and then identifies the contribution of each component to the spectrum with characteristic of non-harmonic order by analyzing noise and vibration signals of each component. The result shows that cepstrum analysis method can extract source signal from the complex spectrum waveform effectively, thus facilitate the identification of noise and vibration sources. Copyright © 2012 SAE International.

Qin J.,State Key Laboratory of Engines | Li X.,State Key Laboratory of Engines | Pei Y.,State Key Laboratory of Engines
SAE Technical Papers | Year: 2014

The aim of this research is to experimentally investigate the effects of combustion parameters [ignition timings, injection timings, excess air ratio ()] and lubricating oil on particulate matter (PM) emissions from a 2.0 L turbo-charged gasoline direct injection (T-GDI) engine fueled with gasoline (octane number = 97), methanol/gasoline blends and pure methanol. The results of this paper show that the PM number concentration mostly presents a typical bimodal distribution in figures. The particle number concentration mainly concentrates in the nucleation mode. With the increase of methanol volume fraction in the blended fuel, the PM emissions decrease significantly. Furthermore, there are few particles when the engine fueled with pure methanol. As advancing ignition timing, the total PM number rises by over about 200%. Under the pre-ignition condition, the higher in-cylinder temperature may also accelerate the formation of the nucleation mode particles. As advancing injection timing, PM emissions decrease first, and then increase. As decreasing , the total PM number would be more than doubled due to the rich air-fuel mixture. The lower may significantly decelerate the oxidation trend of the PM in the combustion process, so that the PM number increases rapidly. The existence of lubricating oil shows a very great impact on PM emissions of T-GDI engine. As increasing a small volume fraction of lubricating oil in the fuel, the PM number significantly increases by several times, especially for accumulation mode particles. Copyright © 2014 SAE International.

Wang X.,State Key Laboratory of Engines | Shu G.-Q.,State Key Laboratory of Engines | Tian H.,State Key Laboratory of Engines | Liang Y.,State Key Laboratory of Engines
SAE Technical Papers | Year: 2014

Currently, the thermal efficiency of vessel diesels only reaches 48∼51%, and the rest energy is rejected to the environment in forms of exhaust, cooling water, engine oil and so on. Meanwhile, energy is required when generating electricity and fresh water that are necessary for vessels. A system that combines the ORC thermal electric generation system with the single-effect evaporating desalination system simultaneously driven by waste heat of charge air is proposed. The research object was 12S90ME-C9.2 diesel engine produced by MAN corp., and a calculation model of the system is built by MATLAB. The variation of the output power, the thermal efficiency and the freshwater production with some operational parameters of the combined system are calculated and analyzed. On the other hand, under the condition of an assumed freshwater production 110.3t/d, the variation of the charge air temperature at the outlet of the desalination evaporator with some operational parameters of the system is studied in the paper. Copyright © 2014 SAE International.

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