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

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 2127 ◽  
Author(s):  
Junhong Zhang ◽  
Zhexuan Xu ◽  
Jiewei Lin ◽  
Zefeng Lin ◽  
Jingchao Wang ◽  
...  

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.

2021 ◽  
pp. 146808742110464
Author(s):  
Yang Hua

Ether and ester fuels can work in the existing internal combustion (IC) engine with some important advantages. This work comprehensively reviews and summarizes the literatures on ether fuels represented by DME, DEE, DBE, DGM, and DMM, and ester fuels represented by DMC and biodiesel from three aspects of properties, production and engine application, so as to prove their feasibility and prospects as alternative fuels for compression ignition (CI) and spark ignition (SI) engines. These studies cover the effects of ether and ester fuels applied in the form of single fuel, mixed fuel, dual-fuel, and multi-fuel on engine performance, combustion and emission characteristics. The evaluation indexes mainly include torque, power, BTE, BSFC, ignition delay, heat release rate, pressure rise rate, combustion duration, exhaust gas temperature, CO, HC, NOx, PM, and smoke. The results show that ethers and esters have varying degrees of impact on engine performance, combustion and emissions. They can basically improve the thermal efficiency of the engine and reduce particulate emissions, but their effects on power, fuel consumption, combustion process, and CO, HC, and NOx emissions are uncertain, which is due to the coupling of operating conditions, fuel molecular structure, in-cylinder environment and application methods. By changing the injection strategy, adjusting the EGR rate, adopting a new combustion mode, adding improvers or synergizing multiple fuels, adverse effects can be avoided and the benefits of oxygenated fuel can be maximized. Finally, some challenges faced by alternative fuels and future research directions are analyzed.


Author(s):  
T. Mitchell ◽  
M. Salah ◽  
J. Wagner ◽  
D. Dawson

The automotive cooling system has unrealized potential to improve internal combustion engine performance through enhanced coolant temperature control and reduced parasitic losses. Advanced automotive thermal management systems use controllable actuators (e.g., smart thermostat valve, variable speed water pump, and electric radiator fan) that must work in harmony to control engine temperature. One important area of cooling system operation is warm-up, during which fluid flow is regulated between the bypass and radiator loops. A fundamental question arises regarding the usefulness of the common thermostat valve. In this paper, four different thermostat configurations were analyzed, with accompanying linear and nonlinear control algorithms, to investigate warm-up behaviors and thermostat valve operations. The configurations considered include factory, two-way valve, three-way valve, and no valve. Representative experimental testing was conducted on a steam-based thermal bench to examine the effectiveness of each valve configuration in the engine cooling system. The results clearly demonstrate that the three-way valve has the best performance as noted by the excellent warm-up time, temperature tracking, and cooling system power consumption.


2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Tatjana Stanivuk ◽  
Branko Lalić ◽  
Jelena Žanić Mikuličić ◽  
Marko Šundov

Every internal combustion engine operates on the principle of converting thermal energy into mechanical work. During fuel combustion in the engine cylinders, the heat is released. It also has its negative effects; one is overheating of the engine cylinders and the engine in general. Since the engine parts are made of metal with its own thermal characteristics, the optimal temperature must be achieved in order to protect the components from overheating and, thus, from undesirable consequences of overheating. For this purpose, cooling medium is used as a means of maintaining the optimum temperature. Keeping the system functional as long as possible and minimizing possible deviations are very complex and difficult tasks. The complexity of the marine cooling system requires finding the optimal modes of operation, which results in an increased use of simulation models. This paper indicates advantages of using system dynamics as a tool for simulating certain events in a very realistic and economically acceptable way to prevent negative consequences for the entire marine system. System dynamics became an indispensable segment of designing various systems as well as the diesel engine cooling system.


Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1148 ◽  
Author(s):  
Teresa Castiglione ◽  
Pietropaolo Morrone ◽  
Luigi Falbo ◽  
Diego Perrone ◽  
Sergio Bova

Improvements in internal combustion engine efficiency can be achieved with proper thermal management. In this work, a simulation tool for the preliminary analysis of the engine cooling control is developed and a model-based controller, which enforces the coolant flow rate by means of an electrically driven pump is presented. The controller optimizes the coolant flow rate under each engine operating condition to guarantee that the engine temperatures and the coolant boiling levels are kept inside prescribed constraints, which guarantees efficient and safe engine operation. The methodology is validated at the experimental test rig. Several control strategies are analyzed during a standard homologation cycle and a comparison of the proposed methodology and the adoption of the standard belt-driven pump is provided. The results show that, according to the control strategy requirements, a fuel consumption reduction of up to about 8% with respect to the traditional cooling system can be achieved over a whole driving cycle. This proves that the proposed methodology is a useful tool for appropriately cooling the engine under the whole range of possible operating conditions.


Energies ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1420 ◽  
Author(s):  
Michele Becciani ◽  
Luca Romani ◽  
Giovanni Vichi ◽  
Alessandro Bianchini ◽  
Go Asai ◽  
...  

In order to ensure a high level of performance and to comply with the increasingly severe limitations in terms of fuel consumption and pollution emissions, modern diesel engines need continuous monitoring of their operating conditions by their control units. With particular focus on turbocharged engines, which are presently the standard in a large number of applications, the use of the average and the instantaneous turbocharger speeds is thought to represent a valuable feedback of the engine behavior, especially for the identification of the cylinder-to-cylinder injection variations. The correct operation of the injectors and control of the injected fuel quantity allow the controller to ensure the right combustion process and maintain engine performance. In the present study, two different techniques are presented to fit this scope. The techniques are discussed and experimentally validated, leading to the definition of an integrated control strategy, which features the main benefits of the two, and is able to correctly detect the cylinder-to-cylinder injection variation and, consequently, properly correct the injection in each cylinder in order to balance the engine behavior. In addition, the possibility of detecting misfiring events was assessed.


2019 ◽  
Vol 178 (3) ◽  
pp. 27-37 ◽  
Author(s):  
Denys STEPANENKO ◽  
Zbigniew KNEBA

The mathematical description of combustion process in the internal combustion engines is a very difficult task, due to the variety of phenomena that occurring in the engine from the moment when the fuel-air mixture ignites up to the moment when intake and exhaust valves beginning open. Modeling of the combustion process plays an important role in the engine simulation, which allows to predict in-cylinder pressure during the combustion, engine performance and environmental impact with high accuracy. The toxic emissions, which appears as a result of fuels combustion, are one of the main environmental problem and as a result the air pollutant regulations are increasingly stringent, what makes the investigation of the combustion process to be a relevant task.


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