Ouyang Guang-yao

Development of an Electromechanical Model for Piezo Actuated Common Rail Injectors

The challenge for the high speed direct injection (HSDI) diesel engines today is to reduce harmful emissions of diesel engines, such as particulate matter (PM) and Nitrogen oxides (NOx), and enhance the fuel efficiency and power. To meet this challenge, more accurate control of injection parameters such as the injection timing, injection rate, and injection quantity is required. Compared with solenoid actuated injectors, the piezo actuated injectors can reduce the transition time for the start and end of the fuel injection event, resulting in more accurate and faster injections, and are gradually replacing the solenoid injectors. In this study, an electromechanical model of a piezo injector is developed with MATLAB/Simulink. The piezo injector model consists of three subsystems: the piezoelectric stack actuator subsystem, the mechanical subsystem and the hydraulic subsystem. A lumped parameter electromechanical model is used for describing the nonlinear behavior of the piezoelectric stack actuator. Different operating conditions of the injection system are modeled and tested. The model has been used to provide insight into the operating conditions of the piezo injector and highlight the application to injection system design.

Research upon Fault Diagnosis Expert System Based on Fuzzy Neural Network

The traditional Expert System has many shortcomings, for instance, its weak knowledge acquisition capability and empirical knowledge’s expression uncertainty. To solve these bottleneck problems, A strategy on fault diagnosis expert system which is based upon fuzzy theory and ANN(ANN:artificial neural network) technique is put forward in this paper, as also its principle, construction, algorithm are all presented. Its performance has been proved to be very excellent when used upon the diesel fuel system classified fault diagnosis.

Thermocouple sensor technology applied in detecting thermal flaw inner cylinder head

Under Analyzing temperature field distribution of cylinder head, the flaw inner cylinder head was machined on electric discharge machine. According to engine practical working condition, a special experimental platform was set up to detect flaw inner cylinder head by using thermocouple sensor. The results showed thermocouple sensors fixed in cylinder head can directly detect flaw, especially on point 2 and point 8, which were near the flaw position, and can provide effective method for further monitoring thermal condition of cylinder head.

Computer Aided Numerical Analysis upon the Connecting Rod Bearing Cave Corroding Fault

An exceptional breakage on the connecting rod bearing is discovered during the repair of one type of marine diesel engine, and it is found that the fault appears very popular through general investigation, so it is very necessary that the reason for the fault be found to avoid the occurrence of the fault again. In this paper, the axis orbit shape is solved with the Holland algorithm firstly, and then the precise oil film pressure distributionof the bearing wall is obtained by taking advantage of the FEM(FEM: Finite Element Method), finally the cause for the fault is got, Besides this, further research on several improved measures are put in force, which provides powerful theory evidence for both the subsequent rational usage and the configuration betterment of the connecting rod bearing.

Study on Flowlimiter of High Pressure Common-rail System

A flowlimiter is one of the important safety links in the high pressure common-rail system. According to the typical structure of the flowlimiter in foreign CR system, its working principle was analyzed and its simulation model and mathematics model were set up, then the Matlab/Simulink calculation were done and the key parameters were selected. Finally, the samples were manufactured and tested.

Structural design and theoretical research on the pressure-intensified high-pressure common-rail system

As the development of combustion theory, the higher requirement was putted forward to the fuel injection rate and the injection pressure, namely adjustable fuel injection rate and multiple injection and super-high pressure injection. Pressure-intensified High-pressure Common-Rail System(PHCRS) is a well system which could meet these higher requirements. In this article, structural style of the solenoid valve and the determination of pressure ratio and the design and installation of offsetting spring were researched profoundly. At last, the structure and the key parameters of the Electrical Control Pressure Amplifier(ECPA) which is suited to the system was defined.

Computational Fluid Dynamics Technology Applied in Flow Analysis in Diesel Engine's Cooling Water Jacket

Using computational fluid dynamics software, the fluid flow in cooling water jacket of HPD diesel engine is studied. Results show that all parts in A Row cylinders cooling water jacket have a better cooling effect, such as in cylinder block and in fire deck. And cooling effect for each cylinder is uniform. Total pressure loss through cooling water jacket is 32.6kPa. The size of water up-holes is better for cooling cylinder head, which can also provide boundary conditions for further calculating temperature field of cylinder head.

Study on Solid-Fluid Coupled Heat Transfer Simulation of Cylinder Head of High Power Density Diesel Engine

On the base of three-dimensional model of HPD diesel engine cooling system water jacket and cylinder head, using Fire mesh module of the AVL software, the grid models were built up, the interface of the head and inner water jacket was coupled. Dependent on boundary conditions simulated on the grid model of cooling system water jacket, using the method of dispersing and resolving, the coupled grid model was calculated and the temperature of the cylinder head was obtained under the condition of rated speed and power. The simulating results are well matched with the experimental results, which can provide gist for further calculating thermal stress and thermal crack.

Simulation on thermal performance parameters of gas-fired in cylinder based on Boost software

Using Boost module of AVL software, a simulating system for modeling working procedure of engine was established. On the base of zero-dimensional combustion model, dependent on structural and thermodynamic parameters of engine, applied Vibe heat release model and WOSCHNI 1978 heat transfer model, the working procedure of engine was modeled. By optimizing specified performance parameters of engine, a satisfying simulating system was set up, and then thermal performance parameters of gas-fired in cylinder were obtained, which can provide heat transfer boundaries for further calculating cylinder head temperature field.

Demodulation of instantaneous rotational speed of diesel engine based on Hilbert transform

To measure diesel engine rotational speed, special 84-teethed wheel is fixed across the engine output shaft, and magnetoelectric transducer mounted above the wheel. The induced electromotive force between the tooth and the sensor is measured, whose frequency characteristics contains the engine speed information. Engine instantaneous speed is extracted by counting process method and Hilbert demodulation method respectively, and their differences are analyzed. Taking no tooth wheel indexing mismachining tolerance into consideration, the time resolution from the counting process mainly lies on the teeth number. While the number is limited, the result cannot be satisfactory. And its amplitude error can be guaranteed within need only by greater sampling frequency. Comparatively, time resolution of the engine instantaneous speed from the Hilbert methods depends on the sampling frequency, so it is relatively fine. And its error mainly results from the signal processing, avoiding high sampling frequency demand.