Characterization of the Effect of Exhaust Back Pressure on Crank Angle-Resolved Exhaust Exergy in a Diesel Engine

Author(s):  
H. Mahabadipour ◽  
K. R. Partridge ◽  
P. R. Jha ◽  
K. K. Srinivasan ◽  
S. R. Krishnan

To enable efficient exhaust waste energy recovery (WER), it is important to characterize the exergy available in engine exhaust flows. In a recent article (Mahabadipour et al., 2018, Appl. Energy, 216, pp. 31–44), the authors introduced a new methodology for quantifying crank angle-resolved exhaust exergy (including its thermal and mechanical components) for the two exhaust phases, viz., the “blowdown” phase and the “displacement” phase. The present work combines experimental measurements with GT-SUITE simulations to investigate the effect of exhaust back-pressure (Pb) on crank angle-resolved exhaust exergy in a single-cylinder research engine (SCRE). To this end, Pb values of 1, 1.4, and 1.8 bar are considered for conventional diesel combustion on the SCRE. Furthermore, the effect of boost pressure (Pin) between 1.2 and 2.4 bar on the thermal and mechanical components of exhaust exergy is reported at different Pb. The exergy available in the blowdown and the displacement phases of the exhaust process is also quantified. Regardless of Pin, with increasing Pb, the cumulative exergy percentage in the blowdown phase reduced uniformly. For example, at Pin = 1.5 bar and 1500 rpm engine speed, the cumulative exergy percentage in the blowdown phase decreased from 34% to 17% when Pb increased from 1 bar to 1.8 bar. The percentage of fuel exergy available as exhaust exergy was quantified. For instance, this normalized cumulative exergy in the exhaust increased from 10% to 21% when Pb increased from 1 bar to 1.8 bar at 1200 rpm. Finally, although the present work focused on exhaust exergy results for diesel combustion in the SCRE, the overall methodology can be easily adopted to study exhaust exergy flows in different engines and different combustion modes to enable efficient exhaust WER.

Author(s):  
H. Mahabadipour ◽  
K. R. Partridge ◽  
P. R. Jha ◽  
K. K. Srinivasan ◽  
S. R. Krishnan

To enable efficient exhaust waste energy recovery (WER), it is important to characterize the exergy available in engine exhaust flows. In a recent article (Mahabadipour et al. (2018), Applied Energy, Vol. 216, pp. 31–44), the authors introduced a new methodology for quantifying crank angle-resolved exhaust exergy (including its thermal and mechanical components) for the two exhaust phases, viz., the “blowdown” phase and the “displacement” phase. The present work combines experimental measurements with GT-SUITE simulations to investigate the effect of exhaust back-pressure (Pb) on crank angle-resolved exhaust exergy in a single-cylinder research engine (SCRE). To this end, Pb values of 1, 1.4, and 1.8 bar are considered for conventional diesel combustion on the SCRE. Furthermore, the effect of boost pressure (Pin) between 1.2 to 2.4 bar on the thermal and mechanical components of exhaust exergy are reported at different Pb. The exergy available in the blowdown and the displacement phases of the exhaust process are also quantified. Regardless of Pin, with increasing Pb, the cumulative exergy percentage in the blowdown phase reduced uniformly. For example, at Pin = 1.5 bar and 1500 rpm engine speed, the cumulative exergy percentage in the blowdown phase decreased from 34% to 17% when Pb increased from 1 bar to 1.8 bar. The percentage of fuel exergy available as exhaust exergy was quantified. For instance, this normalized cumulative exergy in the exhaust increased from 10% to 21% when Pb increased from 1 bar to 1.8 bar at 1200 rpm. Finally, although the present work focused on exhaust exergy results for diesel combustion in the SCRE, the overall methodology can be easily adopted to study exhaust exergy flows in different engines and different combustion modes to enable efficient exhaust WER.


2001 ◽  
Vol 244 (1) ◽  
pp. 79-106 ◽  
Author(s):  
M. AYADI ◽  
S. FRIKHA ◽  
P.-Y. HENNION ◽  
R. WILLATS

2000 ◽  
Author(s):  
David R. Snelling ◽  
Gregory J. Smallwood ◽  
Robert A. Sawchuk ◽  
W. Stuart Neill ◽  
Daniel Gareau ◽  
...  

2017 ◽  
Vol 19 (2) ◽  
pp. 214-229 ◽  
Author(s):  
Daniel Neumann ◽  
Christian Jörg ◽  
Nils Peschke ◽  
Joschka Schaub ◽  
Thorsten Schnorbus

The complexity of the development processes for advanced diesel engines has significantly increased during the last decades. A further increase is to be expected, due to more restrictive emission legislations and new certification cycles. This trend leads to a higher time exposure at engine test benches, thus resulting in higher costs. To counter this problem, virtual engine development strategies are being increasingly used. To calibrate the complete powertrain and various driving situations, model in the loop and hardware in the loop concepts have become more important. The main effort in this context is the development of very accurate but also real-time capable engine models. Besides the correct modeling of ambient condition and driver behavior, the simulation of the combustion process is a major objective. The main challenge of modeling a diesel combustion process is the description of mixture formation, self-ignition and combustion as precisely as possible. For this purpose, this article introduces a novel combustion simulation approach that is capable of predicting various combustion properties of a diesel process. This includes the calculation of crank angle resolved combustion traces, such as heat release and other thermodynamic in-cylinder states. Furthermore, various combustion characteristics, such as combustion phasing, maximum gradients and engine-out temperature, are available as simulation output. All calculations are based on a physical zero-dimensional heat release model. The resulting reduction of the calibration effort and the improved model robustness are the major benefits in comparison to conventional data-driven combustion models. The calibration parameters directly refer to geometric and thermodynamic properties of a given engine configuration. Main input variables to the model are the fuel injection profile and air path–related states such as exhaust gas recirculation rate and boost pressure. Thus, multiple injection event strategies or novel air path control structures for future engine control concepts can be analyzed.


Entropy ◽  
2020 ◽  
Vol 22 (2) ◽  
pp. 254
Author(s):  
Miao Cai ◽  
Peng Cui ◽  
Yikang Qin ◽  
Daoshuang Geng ◽  
Qiqin Wei ◽  
...  

Understanding the defect characterization of electronic and mechanical components is a crucial step in diagnosing component lifetime. Technologies for determining reliability, such as thermal modeling, cohesion modeling, statistical distribution, and entropy generation analysis, have been developed widely. Defect analysis based on the irreversibility entropy generation methodology is favorable for electronic and mechanical components because the second law of thermodynamics plays a unique role in the analysis of various damage assessment problems encountered in the engineering field. In recent years, numerical and theoretical studies involving entropy generation methodologies have been carried out to predict and diagnose the lifetime of electronic and mechanical components. This work aimed to review previous defect analysis studies that used entropy generation methodologies for electronic and mechanical components. The methodologies are classified into two categories, namely, damage analysis for electronic devices and defect diagnosis for mechanical components. Entropy generation formulations are also divided into two detailed derivations and are summarized and discussed by combining their applications. This work is expected to clarify the relationship among entropy generation methodologies, and benefit the research and development of reliable engineering components.


Author(s):  
Jinli Wang ◽  
Fuyuan Yang ◽  
Minggao Ouyang ◽  
Ying Huang

Cylinder pressure based combustion state control is a direction that has drawn much attention in the field of internal combustion engine control, especially in the field of diesel HCCI (Homogeneous Charge Compression Ignition) research. In-cylinder pressure sensors have the potential to diagnose or even replace many traditional sensors, including camshaft and crankshaft sensors. This paper did research on engine synchronization method based on in-cylinder pressure signal. The research was based on a 4-cylinder high pressure common rail diesel engine equipped with 4 PSG (Pressure Sensor Glow Plug) type piezo-resistance cylinder pressure sensors, intended for HCCI research. Through theoretical analysis and experimental proof, methods and models for cylinder identification, engine phase estimation and engine speed estimation are given and further verified by experiments. Results show that cylinder pressure sensor could be used to identify cylinder instead of cam shaft sensor. The models for engine phase and speed estimation have been proved to have precision of 3° crank angle and 4.6rpm, respectively. The precision of engine phase and speed estimation provides a possibility for the engine to run if the crankshaft sensor fails, but more researches have to be carried out with respect to crankshaft sensor replacement.


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