Engine Cycle-by-Cycle Cylinder Wall Temperature Observer-Based Estimation Using Cylinder Pressure Signals

2011 ◽  
Author(s):  
Fengjun Yan ◽  
Junmin Wang
Keyword(s):  
Heat Transfer ◽  
Wall Temperature ◽  
Disturbance Observer ◽  
Fuel Injection ◽  
Cold Start ◽  
Estimation Methods ◽  
Frequency Noise ◽  
Cylinder Wall ◽  
Cylinder Pressure ◽  
Temperature Estimation

Estimating cylinder wall temperature before start of fuel injection in a dynamic and cycle-by-cycle way is important for advanced combustion mode engine control, particularly during cold-start and transient operations. In this paper, two methods for cylinder wall temperature estimation, based on disturbance observer designs, are proposed. The heat transfer through cylinder wall is viewed as a disturbance in total heat release. With disturbance observers, this heat transfer can be estimated in finite time and thus to calculate the cylinder wall temperature. To handle the high frequency noise issues in cylinder pressure signals, a robust disturbance observer is proposed and compared with a typical design method. The effectiveness of such cylinder wall temperature estimation methods are demonstrated and compared with engine experimental data obtained during a cold-start process.

A Fundamental Thermodynamic Study on the Effects of Engine Scale in Diesel Engines

2019 ◽  
Author(s):  
Kevin J. Burnett ◽  
Ashwani K. Gupta ◽  
Jim S. Cowart
Keyword(s):  
Heat Transfer ◽  
Surface Area ◽  
Wall Temperature ◽  
Diesel Engines ◽  
Cold Start ◽  
Cylinder Wall ◽  
Piston Speed ◽  
Heat Effects ◽  
Wide Range ◽  
Significant Difference

Abstract The Navy has a wide range of diesel engines with bore sizes varying by a factor of four. In general, diesel engines can have bore scaling over a full order of magnitude. As an engine cylinder gets larger its surface area to volume ratio reduces significantly, which in turn affects in-cylinder heat transfer. In this study, a fundamental generalized thermodynamic model of diesel engines was developed. The various key model effects were systematically analyzed along with engine bore size. Further, cylinder wall temperature was varied across a range of cold start to stabilized operating temperatures. The results of this study show that smaller bore diesel engines are always more sensitive to cold start conditions. The effect is reduced with increasing wall temperature yet smaller diesel engines have cooler end-of-compression temperatures as comparted to larger engines. The effects of engine speed, in which mean piston speed is held constant, tend to modestly reduce the differences between various size diesel engines due to non-linear heat transfer effects. When variable specific heat effects are correctly considered, end-of-compression air charge temperatures are only modestly different as a function of engine bore size. The most significant difference is the overall reduced heat transfer in larger engines due to the surface area to volume effect. A difference of a factor of three for in cylinder heat transfer relative to in-cylinder inducted air mass is predicted being much greater for the smaller engines. Higher exhaust temperatures are also characteristic of the larger bore engines. This allows more combustion work to be delivered to the piston with a correspondingly higher thermal efficiency for larger diesel engines. Future work will evaluate fuel effects on varying bore size.

Engine Cycle-by-Cycle Cylinder Wall Temperature Observer-Based Estimation Through Cylinder Pressure Signals

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Fengjun Yan ◽  
Junmin Wang
Keyword(s):  
Wall Temperature ◽  
Disturbance Observer ◽  
Design Method ◽  
Operating Conditions ◽  
Cylinder Wall ◽  
Cylinder Pressure ◽  
Combustion Mode ◽  
Estimation Errors ◽  
Engine Model ◽  
Cycle Basis

The effects caused by the cylinder wall temperature variations are nontrivial in advanced combustion mode engine control, particularly in cold-start processes and transients when the combustion mode switches from one to another. Being affected by the engine coolant and operating conditions on a cycle-by-cycle basis, cylinder wall temperature is difficult to be directly measured, and it is typically viewed as an unknown disturbance or estimated as a quasi-static parameter. However, such treatments of the cylinder wall temperature may not be sufficient in sophisticated control of combustion processes. This paper aims to estimate the cylinder wall temperature, on a cycle-by-cycle basis, through cylinder pressure signals in diesel engines. In the proposed methods, the cylinder wall temperature is modeled as a disturbance in the in-cylinder pressure dynamics. Thus, the wall temperature in each cylinder can be estimated, on a cycle-by-cycle basis, by the disturbance observer methods in finite crankshaft angles. Furthermore, to reduce the cylinder wall temperature estimation errors caused by the high-frequency noises in the cylinder pressure signals, a robust disturbance observer is proposed and compared with a typical design method. Through GT-Power engine model simulations and engine experimental results, the observer effectiveness, noise attenuation properties, and applications on a multicylinder diesel engine are evaluated.

Development of Temperature Estimation Method for a Gas Turbine Transition Piece

2016 ◽  
Author(s):  
Mitsutoshi Okada ◽  
Toshihiko Takahashi ◽  
Susumu Yamada ◽  
Takayuki Ozeki ◽  
Tomoharu Fujii
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Gas Turbine ◽  
Estimation Method ◽  
Life Assessment ◽  
Estimation Methods ◽  
Test Time ◽  
Internal Cooling ◽  
Temperature Estimation ◽  
Transition Piece

Temperature estimation methods for a transition piece of a gas turbine are developed in terms of microstructural changes and computational fluid dynamics (CFD) for life assessment. Temperature is estimated to be low around the center of the component where thermal barrier coating (TBC) is deposited on the Ni-base superalloy and a combination of internal cooling and film cooling is also applied. Test specimens are prepared from the above area for a high-temperature heating test in air. The microstructure in the superalloy and TBC is investigated after the test. The thermally grown oxide (TGO) formed on the bondcoat surface increases with the square root of the test time, and on the basis of this relation, a temperature-estimation equation is obtained. The estimated temperature distribution is compared with a numerical heat transfer simulation by means of CFD. The geometry of the transition piece with internal cooling structure is acquired using an X-ray computerized radiography and a laser digitizer, and it is modeled for the numerical simulation. The heat conduction analysis is applied to the transition piece, and the convection and radiation heat transfer analyses are applied to the gas path and internal cooling flow. These analyses are conjugated to estimate the temperature distribution. The simulation result agrees well with the estimation using TGO thickness.

Similarity Solution of Unaxisymmetric Heat Transfer in Stagnation-Point Flow on a Cylinder With Simultaneous Axial and Rotational Movements

2008 ◽  
Vol 130 (5) ◽  
Author(s):  
Asghar B. Rahimi ◽  
Reza Saleh
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Stagnation Point ◽  
Wall Temperature ◽  
Similarity Solution ◽  
Free Stream ◽  
Wall Heat Flux ◽  
Cylinder Wall ◽  
Local Coefficient ◽  
Unsteady Viscous Flow

Similarity solution of unaxisymmetric heat transfer of an unsteady viscous flow in the vicinity of an axisymmetric stagnation point of an infinite circular cylinder with simultaneous axial and rotational movement along with transpiration Uo is investigated when the angular velocity, axial velocity, and wall temperature or wall heat flux vary arbitrarily with time. The impinging free stream is steady and with a strain rate of k¯. The results presented are found by numerical integration. The local coefficient of heat transfer (Nusselt number) is found to be independent of time and place, though the cylinder wall temperature or wall heat flux are functions of both time and place.

scholarly journals Experimental Thermal Analysis of Diesel Engine Piston and Cylinder Wall

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Subodh Kumar Sharma ◽  
P. K. Saini ◽  
N. K. Samria
Keyword(s):  
Heat Transfer ◽  
Diesel Engine ◽  
Wall Temperature ◽  
Thermal Loading ◽  
Thermal Stresses ◽  
Transfer Model ◽  
Cylinder Wall ◽  
Fe Model ◽  
Transfer Coefficients ◽  
Thermocouple Wire

Knowledge of piston and cylinder wall temperature is necessary to estimate the thermal stresses at different points; this gives an idea to the designer to take care of weaker cross section area. Along with that, this temperature also allows the calculation of heat losses through piston and cylinder wall. The proposed methodology has been successfully applied to a water-cooled four-stroke direct-injection diesel engine and it allows the estimation of the piston and cylinder wall temperature. The methodology described here combines numerical simulations based on FEM models and experimental procedures based on the use of thermocouples. Purposes of this investigation are to measure the distortion in the piston, temperature, and radial thermal stresses after thermal loading. To check the validity of the heat transfer model, measure the temperature through direct measurement using thermocouple wire at several points on the piston and cylinder wall. In order to prevent thermocouple wire entanglement, a suitable pathway was designed. Appropriate averaged thermal boundary conditions such as heat transfer coefficients were set on different surfaces for FE model. The study includes the effects of the thermal conductivity of the material of piston, piston rings, and combustion chamber wall. Results show variation of temperature, stresses, and deformation at various points on the piston.

scholarly journals Large-Eddy Simulation Study of Flow and Heat Transfer in Swirling and Non-Swirling Impinging Jets on a Semi-Cylinder Concave Target

2021 ◽  
Vol 11 (15) ◽  
pp. 7167
Author(s):  
Liang Xu ◽  
Xu Zhao ◽  
Lei Xi ◽  
Yonghao Ma ◽  
Jianmin Gao ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Large Eddy Simulation ◽  
Wall Temperature ◽  
Target Surface ◽  
Impinging Jets ◽  
Small Scale ◽  
Complex Flow ◽  
Eddy Simulation ◽  
Flow And Heat Transfer ◽  
Large Eddy

Swirling impinging jet (SIJ) is considered as an effective means to achieve uniform cooling at high heat transfer rates, and the complex flow structure and its mechanism of enhancing heat transfer have attracted much attention in recent years. The large eddy simulation (LES) technique is employed to analyze the flow fields of swirling and non-swirling impinging jet emanating from a hole with four spiral and straight grooves, respectively, at a relatively high Reynolds number (Re) of 16,000 and a small jet spacing of H/D = 2 on a concave surface with uniform heat flux. Firstly, this work analyzes two different sub-grid stress models, and LES with the wall-adapting local eddy-viscosity model (WALEM) is established for accurately predicting flow and heat transfer performance of SIJ on a flat surface. The complex flow field structures, spectral characteristics, time-averaged flow characteristics and heat transfer on the target surface for the swirling and non-swirling impinging jets are compared in detail using the established method. The results show that small-scale recirculation vortices near the wall change the nearby flow into an unstable microwave state, resulting in small-scale fluctuation of the local Nusselt number (Nu) of the wall. There is a stable recirculation vortex at the stagnation point of the target surface, and the axial and radial fluctuating speeds are consistent with the fluctuating wall temperature. With the increase in the radial radius away from the stagnation point, the main frequency of the fluctuation of wall temperature coincides with the main frequency of the fluctuation of radial fluctuating velocity at x/D = 0.5. Compared with 0° straight hole, 45° spiral hole has a larger fluctuating speed because of speed deflection, resulting in a larger turbulence intensity and a stronger air transport capacity. The heat transfer intensity of the 45° spiral hole on the target surface is slightly improved within 5–10%.

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