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Liu Jingping

Bio: Liu Jingping is an academic researcher from Hunan University. The author has contributed to research in topics: Exhaust gas recirculation & Petrol engine. The author has an hindex of 2, co-authored 8 publications receiving 11 citations.

Papers
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Proceedings ArticleDOI
Deng Banglin1, Liu Jingping1, Yang Jing1, Feng Renhua1, Fu Jianqin1, Chen Shanping1 
06 Jan 2011
TL;DR: In this article, the fatigue and friction of big end bearing on an engine connecting rod by combining the multi-body dynamics and hydrodynamic lubrication model was studied. And the simulation results showed a good agreement when contrast the simulation result to the bearing wear in the experiment.
Abstract: This paper has studied the fatigue and friction of big end bearing on an engine connecting rod by combining the multi-body dynamics and hydrodynamic lubrication model. First, the basic equations and the application on AVL-Excite software platform of multi-body dynamics have been described in detail. Then, introduce the hydrodynamic lubrication model, which is the extended Reynolds equation derived from the Navier-Stokes equation and the equation of continuity. After that, carry out the static calculation of connecting rod assembly. At the same time, multi-body dynamics analysis has been performed and stress history can be obtained by finite element data recovery. Next, execute the fatigue analysis combining the Static stress and dynamic stress, safety factor distribution of connecting rod will be obtained as result. At last, detailed friction analysis of the big-end bearing has been performed. And got a good agreement when contrast the simulation results to the Bearing wear in the experiment.

3 citations

Proceedings ArticleDOI
06 Jan 2011
TL;DR: In this article, a virtual air flow measurement technology combining fast response sensors with 1-dimensional pressure wave action simulation is proposed to estimate the fresh charge mass trapped in-cylinder at the end of the gas exchange process.
Abstract: Accurate control of the in-cylinder air/fuel ratio level is critical for both fuel saving and harmful emission reduction of an internal combustion engine. The fuel injection quantity is easy to control with today’s electronically controlled fuel injection system, the difficulty is how to accurately determine the fresh charge mass trapped in-cylinder at the end of the gas exchange process, especially for transient operation mode of a vehicle when the throttle position, intake air pressure and engine speed are instantaneously changing. No physical airflow meter exists which has satisfactory response time and measurement accuracy. Described in this paper is a renovated air flow measurement technology combining fast response sensors with 1-dimensional pressure wave action simulation. Utilizing two dynamic pressure transducers(2P) to measure pressure fluctuation near the intake and exhaust ports and coupling the measured pressure signals into the numerical solver of a 1-dimensional gas exchange simulation software, together with the instant flow area at valve locations, the instantaneous gas mass flow rate through the engine intake and exhaust ports can be calculated. The fresh mass and un-swept burnt mass fraction trapped in the cylinder could also be traced along the entire gas exchange process. The response time and model accuracy of this synthetic virtual airflow meter technology is validated against GT-Power model and experiment tests, for both steady-state and transient operating modes.

3 citations

Proceedings ArticleDOI
Fu Jianqin1, Liu Jingping1, Deng Banglin1, Feng Kang1, Feng Renhua1 
06 Jan 2011
TL;DR: In this article, a new method for designing and studying engine intake system based on the technology of CAD/CAE/CFD integration is proposed, and the feasibility and effectiveness of the idea is validated through practical example.
Abstract: This article has proposed a new method for designing and studying engine intake system based on the technology of CAD/CAE/CFD integration. Firstly, according to the similarity principle and pressure wave theory, the structure parameters of target engine intake system were defined referencing the similar engine. Then, the intake system parameters were input into GT-power, and the intake system performance was simulated and optimized. Next, the 3-D structure model was designed based on CAD software and optimized values. After that, the key parts of intake system were analyzed and optimized by using CAE and CFD. As a result, a new intake system has been designed. The whole processes of designing and studying intake system included parameters define, performance optimization, structure design, flow calculation, noise and vibration analysis, were coupled together. And the feasibility and effectiveness of the idea was validated through practical example. The study results have provided guidance for designing intake system of engine.

2 citations

Proceedings ArticleDOI
11 Nov 2010
TL;DR: In this paper, a PID controller for robust control of EGR (Exhaust Gas Recirculation) system in a gasoline engine was developed for a GT-power model of the gasoline engine with EGR system.
Abstract: A PID control is developed for robust control of EGR (Exhaust Gas Recirculation) system in a gasoline engine. First a GT-power model of the gasoline engine with EGR system was built and verified. Then a PID controller was built using Simulink/Matlab and coupled with the GT-power engine model. A suitable tuning strategy for the PID controllers is also developed. Its response characteristics and performance are investigated in details. The results show that this PID control system is robust, fast and have good anti-interference performance, which make it very suitable for the variable complicated work condition of gasoline engine.

2 citations

Proceedings ArticleDOI
16 Jan 2013
TL;DR: In this paper, the energy flow characteristics of turbo charging system were studied on a gasoline direct injection engine, and various kinds of intake and exhaust parameters were measured under mapping characteristics, and then the maps of turbocharging system energy flows were acquired by combining energy balance equations.
Abstract: In this paper, the energy flow characteristics of turbo charging system were studied on a gasoline direct injection engine. Based on engine dyno tests, various kinds of intake and exhaust parameters were measured under mapping characteristics, and then the maps of turbo charging system energy flows were acquired by combining energy balance equations. On this basis, the exhaust energy recovery efficiency and energy flow characteristics of turbo charging system were analyzed. Exhaust energy recovery efficiency of turbo charging system mainly depends on the pressure ratio of intake gas, in the whole gasoline engine operating conditions area, exhaust energy recovery efficiency of turbocharger is between 2.5% and 7.5%, and the larger value appears in gasoline engine high load operating conditions.

1 citations


Cited by
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Journal ArticleDOI
TL;DR: A new reliability model for multi-state systems/components with state transition dependency is put forth and the dependency among state transitions is implicitly characterized by copula functions which offer a great flexibility of linking arbitrary marginal distributions together to construct a multivariate distribution.

56 citations

Proceedings ArticleDOI
TL;DR: In this article, a model of the inverted Brayton cycle using finite-time thermodynamics (FTT) is presented to study heat recovery applied to a highly downsizing automotive internal combustion engine.
Abstract: The exhaust gas from an internal combustion engine contains approximately 30% of the thermal energy of combustion. The exhaust-gas heat-recovery systems aim to reclaim a proportion of this energy in a bottoming thermodynamic cycle to raise the overall system thermal efficiency. The inverted Brayton cycle considered as a potential exhaust-gas heat-recovery system is a little-studied approach, especially when applied to small automotive power-plants. Hence, a model of the inverted Brayton cycle using finite-time thermodynamics (FTT) is presented to study heat recovery applied to a highly downsizing automotive internal combustion engine. IBC system consists of a turbine, a heat exchanger and compressors in sequence. The use of IBC turbine is to fully expand the exhaust gas available from the upper cycle. The remaining heat in the exhaust after expansion is rejected by the downstream heat exchanger. Then, the cooled exhaust gases are compressed back up to the ambient pressure by one or more compressors. In this paper, the exhaust conditions available from the engine test bench data were introduced as the inlet conditions of the IBC thermodynamic model to quantify the power recovered by IBC, thereby revealing the benefits of IBC to this particular engine. It should be noted that the test bench data of the baseline engine were collected by the worldwide harmonized light vehicles test procedures (WLTP). WLTP define a global harmonized standard for determining the levels of pollutants and CO2 emissions, fuel consumption. The IBC thermodynamic model was simulated with the following variables: IBC inlet pressure, turbine pressure ratio, heat exchanger effectiveness, turbomachinery efficiencies, and the IBC compression stage. The aim of this paper is to analysis the performance of IBC system when it is applied to a light-duty automotive engine operating in a real world driving cycle.

9 citations

01 Jul 1993
TL;DR: In this paper, the authors present a design process for intake and exhaust system design to control the transfer of acoustic energy from the sources and its emission by the system with minimal loss of engine performance.
Abstract: The aim of intake and exhaust system design is to control the transfer of acoustic energy from the sources and its emission by the system with minimal loss of engine performance. A rational design process depends on the adoption of a design methodology based on predictive modelling of acoustic behaviour. Virtually any system geometry can be modelled by breaking it down to a sequence of simple elements or chambers. An initial design layout is then produced with simple parametric models of individual element behaviour. This design is then refined to prototype level by systematic modification of detail using realistic assessments of system performance in its operational environment. Following prototype validation by practical testing any further necessary development is again assisted by predictive modelling. The application of appropriate procedures is illustrated by a series of practical examples. These concern improvements in interior noise by control of intake noise, of vehicle performance by reducing flow losses, of the environment by control of exhaust emissions and lastly with the control of flow noise. This account concludes with a brief outline of current and new developments involving integrated hybrid design procedures. A further paper is being prepared describing silencer designs with their experimental validation.

8 citations

Dissertation
05 Nov 2019
TL;DR: By evaluating the eligibility of integrating existing system identification and control theories in real automotive applications, this thesis highlights the merits and demerits of these theories and opens up new prospects in the domain of model-based powertrain systems optimization.
Abstract: Powertrain systems optimization in modern automobiles relies on model-based systems engineering to cope with the complex automotive systems and challenging control design requirements. Two prerequisites for model-based powertrain optimization are the powertrain simulator and the control design, which ensures a desirable powertrain operation during driving cycles. This thesis revolves around these prerequisites and belongs to the model-in-the-loop phase of the control development lifecycle. It first aims at identifying control-oriented powertrain systems models, particularly linear black-box models because of the merits they present in terms of accessibility to linear control design and facility of integrating changes in the powertrain system technical definition. It also aims at identifying and controlling powertrain systems featuring transport time delay because integrating the delay in the model and control design is crucial on the former’s system representability and on the latter’s optimality. Based on these premises, we address the powertrain from the engine air-path perspective. We first identify a linear black-box state-space (SS) model of a gasoline engine air-path, using an identification algorithm based on subspace methods. Different model orders and algorithm parameters are tested and those yielding the best identification and validation results are made clear, which leads to an 85% time gain in future similar identifications. While this part considers the air-path as a whole, the rest of the work focuses on specific air-path components, notably the electric throttle (ET), the heat-exchanger, and the exhaust gas recirculation (EGR). Regarding the ET, we inspire from the physical laws governing the throttle functioning to construct a linear-parameter-varying (LPV) mathematical SS model, which serves to set the regression vector structure of the LPV black-box ARX model, which is representative of an ET test bench and reflects its nonlinearities and discontinuities as it varies from one functioning zone to another. To address the questions of heat and mass transport time delays in the engine air-path, we refer to the heat exchanger and the EGR respectively. Recasting the infinite-dimensional hyperbolic partial differential equations (PDEs) describing these transport phenomena as a time-delay system facilitates the adjoint system identification and control design. To that end, a space-averaging technique and the method of characteristics are used to decouple the hyperbolic PDEs describing the advective flows in a heat exchanger, and to reformulate them as a time-delay system. Reducing the error between the output temperature of the model and that of a heat exchanger test-bench is what seeks the gradient-descent method used to identify the parameters of the time-delay system, which surpasses the PDEs in terms of identification accuracy and computational efficiency. On the other hand, the EGR is addressed from a control-oriented perspective, and the PDEs describing the mass transport phenomenon in its tubular structure are recast as a SS system subject to output delay. To regulate the burned gas ratio in the intake gas, the amount of recirculated gas is controlled using two indirect optimal control approaches, taking into account the model’s infinite-dimensional nature and accompanied with the Augmented Lagrangian Uzawa method to guarantee the respect of the input and state constraints, thus resulting in a controller of superior performance than the initially existing PID. In general, this thesis is located half-way between the academic and the industrial sectors. By evaluating the eligibility of integrating existing system identification and control theories in real automotive applications, it highlights the merits and demerits of these theories and opens up new prospects in the domain of model-based powertrain systems optimization.

6 citations

Proceedings ArticleDOI
05 Apr 2016

4 citations