Thermal Characteristics Investigation of the Internal Combustion Engine Cooling-Combustion System Using Thermal Boundary Dynamic Coupling Method and Experimental Verification

Abstract

The engine cooling system must be able to match up with the stable operating conditions so as to guarantee the engine performance. On the working cycle level, however, the dynamic thermo-state of engines has not been considered in the cooling strategy. Besides, the frequent over-cooling boiling inside the gallery changes the cooling capacity constantly. It is necessary to study the coupling effect caused by the interaction of cooling flow and in-cylinder combustion so as to provide details of the dynamic control of cooling systems. To this end, this study develops a coupled modeling scheme of the cooling process considering the interaction of combustion and coolant flow. The global reaction mechanism is used for the combustion process and the multiphase flow method is employed to simulate the coolant flow considering the wall boiling and the interphase forces. The two sub-models exchange information of in-cylinder temperature, heat transfer coefficient, and wall temperature to achieve the coupled computation. The proposed modeling process is verified through the measured diesel engine power, in-cylinder pressure, and fire surface temperature of cylinder head. Then the effects of different cooling conditions on the cyclic engine performances are analyzed and discussed.

Analysis and Optimization of Coupled Thermal Management Systems Used in Vehicles

“…Considering that each system is suitable for different working conditions, this paper analyzes the performance according to the actual working conditions of vehicles. Figure 19 shows that the time percentage of engine speed and torque in different ranges when the vehicle is running in cities and highways [27]. Combined with the net power of three systems under different working conditions, the comprehensive net power of each system under different environmental temperatures under urban and high-speed working conditions can be obtained, as shown in Figure 20.…”

Numerical Calculation Method of Model Predictive Control for Integrated Vehicle Thermal Management Based on Underhood Coupling Thermal Transmission

“…The coolant temperature gradient in the jacket was assumed constant, and was represented by the arithmetic mean value of the engine inlet and outlet temperatures. To establish the convection heat transfer equations, the Hohenberg convection heat transfer model was applied to determine the heat transfer coefficients, specifically and [34]. The convection heat transfer equations of the coolant are defined as…”

Improving the Thermal Efficiency of the Homogeneous Charge Compression Ignition Engine by Using Various Combustion Patterns

“…Many technologies have been developed for improving the efficiency of engines, such as engine downsizing [2][3][4], the Atkinson or Miller cycle [4][5][6], gasoline direct injection (GDI) [7][8][9], the homogeneous charge compression ignition (HCCI) [10][11][12][13][14], reduction of exhaust energy loss [15,16] or heat loss [17][18][19][20], electrical or precisely controlled cooling systems [20][21][22], and combustion phase control [23]. Cesare et al [1] reported that engine downsizing concepts, such as turbocharging combined with GDI, have contributed to the recent improvements of ICEs.…”

“…Legros et al [16] compared various waste heat treatment technologies, such as Rankine cycles, thermoelectric generators, and turbo compounding, and achieved a fuel reduction of up to 6%. Zhang et al [20] proposed a dynamic control of cooling systems and achieved low heat loss. Gao et al [23] used the in-cylinder pressure sensor to calculate the combustion phase and indicated mean effective pressure (IMEP) for maximum fuel efficiency.…”

“…To investigate the thermal efficiency of the ICE, the fuel energy can be considered to be constituted of roughly three equal parts: useful work, heat transfer loss, and exhaust energy loss. Several methods have been proposed for the reduction of heat losses and the recovery of the exhaust energy [15][16][17][18][19][20]. However, most of the proposed methods have drawbacks.…”