scholarly journals Recovery of Exhaust Waste Heat for ICE Using the Beta Type Stirling Engine

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Wail Aladayleh ◽  
Ali Alahmer

This paper investigates the potential of utilizing the exhaust waste heat using an integrated mechanical device with internal combustion engine for the automobiles to increase the fuel economy, the useful power, and the environment safety. One of the ways of utilizing waste heat is to use a Stirling engine. A Stirling engine requires only an external heat source as wasted heat for its operation. Because the exhaust gas temperature may reach 200 to 700°C, Stirling engine will work effectively. The indication work, real shaft power and specific fuel consumption for Stirling engine, and the exhaust power losses for IC engine are calculated. The study shows the availability and possibility of recovery of the waste heat from internal combustion engine using Stirling engine.

2020 ◽  
Vol 39 (1) ◽  
pp. 161-172 ◽  
Author(s):  
A.E. Ikpe ◽  
I.B. Owunna

In this study, a two stroke internal combustion engine was successfully modeled as a closed cycle with the intake, compression, expansion and exhaust processes considered in two strokes of the reciprocating piston. The in-cylinder combusted gases with respect to air-fuel mixture of 14.4:1 in the two stroke engine model were analyzed, showing the dynamics of the combusted gases, the flame pressure and temperature trajectories. It was observed that provided compression and expansion takes place at air-fuel mixture near ideal condition (14.7:1), the combusted gas temperature which occurred in the range of 293.92-3000.60 K is directly proportional to the cylinder gas pressure which occurred in the range of 60.76-80.20 bar. With a heat transfer coefficient of 581.236 W/m2K, the maximum temperature of the IC engine material was found to be 2367.56K at equilibrium and the maximum shear stress was found to be 176 x 102 MPa (1.76 x 105 bar). The 14.4:1 air-fuel mixture implies that 26% O2, 73% N2 and 1% trace gases are the in-cylinder air constituent that will react with 1 mole of hydrocarbon to form the combusted products of 96.2% CO2, 3.2% H2O and 0.6% N2. This will vary in conditions where the air-fuel mixture changes. Keywords: Modelling, Gas dynamics, Two stroke, IC engine, Air-fuel mixture.


Author(s):  
Maohai Wang ◽  
Thomas Josef Daun ◽  
Yangjun Zhang ◽  
Weilin Zhuge

In this paper, the development of a thermoelectric generator (TEG) simulation model and its implementation into an internal combustion engine (ICE) system model are demonstrated. The TEG model is calibrated with respect to an experimental basis presented in a previously published paper. A TEG parameter study, an analysis of the overall system and the interaction between the TEG and the ICE are carried out. The simulation results indicate that the exhaust gas temperature has a much more significant influence on the TEG performance than the exhaust gas mass flow rate. Without considering the influence of additional backpressure, the application of a TEG shows potential to increase the effective engine power; thereby improving the overall efficiency by approximately 0.6 to 1.7% (depending on engine speed and load). However, when taking additional backpressure into account, this gain in effective engine power is reduced slightly, resulting in a change of the efficiency range to between 0.2 and 1.7%. This illustrates the importance of taking the backpressure into account when designing a real world TEG.


2021 ◽  
Vol 313 ◽  
pp. 13001
Author(s):  
Francesco Catapano ◽  
Carmela Perozziello ◽  
Bianca Maria Vaglieco

This work aims to study a Stirling engine (SE) used to recover the heat content of the exhaust gas from an internal combustion engine. The attention has been focused on the heat transfer between the exhaust gas and the working gas inside the heater. Experimental tests have been performed on a two-cylinder gamma-type Stirling engine coupled to a compression ignition engine using a thermally insulated pipe and a cap. A mechanical power of 0.275 kW at 900 rpm SE rotational speed was obtained with a SE efficiency of 11.7%. To investigate how the exhaust gas-heater interaction affects SE efficiency, a 3D model was developed by the authors. The cap-heater system was studied as a shell-and-tubes heat exchanger. Experimental values of temperature and velocity have been set as boundary conditions for the cap, while for the heater, pressure and velocity have been predicted using a 1D adiabatic model adjusted for SE geometry. The results showed that temperature distribution is not uniform in both cylinders, involving that the working pistons do not work in the same way. Therefore, to improve SE efficiency, a proper configuration of SE-CI engine coupling should be designed.


Author(s):  
Manuel Jiménez-Arreola ◽  
Fabio Dal Magro ◽  
Alessandro Romagnoli ◽  
Meng Soon Chiong ◽  
Srithar Rajoo ◽  
...  

Waste heat recovery is seen as one of the key enablers in achieving powertrain of high efficiency. The exhaust waste heat from an internal combustion engine (ICE) is known to be nearly equivalent to its brake power. Any energy recovered from the waste heat, which otherwise would be discarded, may directly enhance the overall thermal efficiency of a powertrain. Rankine cycle (indirect-recovery method) has been a favorable mean of waste heat recovery due to its rather high power density yet imposing significantly lesser back pressure to the engine compared to a direct-recovery method. This paper presents the analytical investigation of a thermal-supercharged ICE compounded with Rankine cycle. This system removes the turbocharger turbine to further mitigate the exhaust back pressure to the engine, and the turbocharger compressor is powered by the waste heat recovered from the exhaust stream. Extra caution has been taken when exchanging the in/output parameters between the engine and Rankine cycle model to have a more realistic predictions. Such configuration improves the engine BSFC performance by 2.4–3.9%. Water, Benzene and R245fa are found to be equally good choice of working fluid for the Rankine cycle, and can further advance the BSFC performance by 4.0–4.8% despite running at minimum pressure setting. The off-design analyses suggested the operating pressure of Rankine cycle and its expander efficiency have the largest influence to the gross system performance.


2008 ◽  
Vol 12 (1) ◽  
pp. 85-102 ◽  
Author(s):  
Miroljub Tomic ◽  
Slobodan Popovic ◽  
Nenad Miljic ◽  
Stojan Petrovic ◽  
Milos Cvetic ◽  
...  

In this paper a simplified procedure of an internal combustion engine in-cylinder pressure record analysis has been presented. The method is very easy for programming and provides quick evaluation of the gas temperature and the rate of combustion. It is based on the consideration proposed by Hohenberg and Killman, but enhances the approach by involving the rate of heat transferred to the walls that was omitted in the original approach. It enables the evaluation of the complete rate of heat released by combustion (often designated as ?gross heat release rate? or ?fuel chemical energy release rate?), not only the rate of heat transferred to the gas (which is often designated as ?net heat release rate?). The accuracy of the method has been also analyzed and it is shown that the errors caused by the simplifications in the model are very small, particularly if the crank angle step is also small. A several practical applications on recorded pressure diagrams taken from both spark ignition and compression ignition engine are presented as well.


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