An Assessment of the Relative Benefits of Miller Cycle and Turbocompounding on a Medium Speed Diesel Engine Using Second Law Analysis

2010 ◽  
Author(s):  
Thomas M. Lavertu ◽  
Roy J. Primus ◽  
Omowoleola C. Akinyemi
Keyword(s):  
Diesel Engine ◽  
Energy Recovery ◽  
Second Law ◽  
Miller Cycle ◽  
Medium Speed ◽  
Power Turbine ◽  
Second Law Analysis ◽  
Exhaust Energy ◽  
The Impact ◽  
Turbine Exhaust

The relative benefit of a power turbine as a means of exhaust energy recovery (i.e., turbocompounding) being used in conjunction with altered intake valve closure timing (Miller cycle) on a medium speed diesel engine has been investigated. An assessment of the impact of these different engine architectures on the various loss mechanisms has been performed using second law analysis. The Miller and turbocompounding cycle modification as well as the combination of the two features were studied and their relative benefits are compared and discussed. Results show the corresponding decrease in effective compression ratio achieved with Miller cycle leads to lower pre-turbine exhaust availability, which decreases the potential benefit of turbocompounding.

Analysis of Throttle Opening Variation Impact on a Diesel Engine Performance Using Second Law of Thermodynamics

2009 ◽  
Author(s):  
B. B. Sahoo ◽  
U. K. Saha ◽  
N. Sahoo ◽  
P. Prusty
Keyword(s):  
Diesel Engine ◽  
Direct Injection ◽  
Fuel Efficiency ◽  
Engine Performance ◽  
Second Law Of Thermodynamics ◽  
Operating Conditions ◽  
Second Law ◽  
Engine Fuel ◽  
Availability Analysis ◽  
Second Law Analysis

The fuel efficiency of a modern diesel engine has decreased due to the recent revisions to emission standards. For an engine fuel economy, the engine speed is to be optimum for an exact throttle opening (TO) position. This work presents an analysis of throttle opening variation impact on a multi-cylinder, direct injection diesel engine with the aid of Second Law of thermodynamics. For this purpose, the engine is run for different throttle openings with several load and speed variations. At a steady engine loading condition, variation in the throttle openings has resulted in different engine speeds. The Second Law analysis, also called ‘Exergy’ analysis, is performed for these different engine speeds at their throttle positions. The Second Law analysis includes brake work, coolant heat transfer, exhaust losses, exergy efficiency, and airfuel ratio. The availability analysis is performed for 70%, 80%, and 90% loads of engine maximum power condition with 50%, 75%, and 100% TO variations. The data are recorded using a computerized engine test unit. Results indicate that the optimum engine operating conditions for 70%, 80% and 90% engine loads are 2000 rpm at 50% TO, 2300 rpm at 75% TO and 3250 rpm at 100% TO respectively.

Introducing a Novel Air Handling Unit Based on Focusing on Turbulent Exhaust Air Energy-Exergy Recovery Potential

2020 ◽  
Vol 142 (11) ◽  
Author(s):  
Yuanzhou Zheng ◽  
Rasool Kalbasi ◽  
Arash Karimipour ◽  
Peng Liu ◽  
Quang-Vu Bach
Keyword(s):  
Energy Consumption ◽  
Energy Demand ◽  
Energy Recovery ◽  
Primary Energy ◽  
Second Law ◽  
The Novel ◽  
Heating Coil ◽  
Recovery Potential ◽  
Air Handling Unit ◽  
Second Law Analysis

Abstract A novel air handling unit (AHU) aimed at reducing energy consumption was introduced in this study. In the proposed novel AHU, the heating coil is completely removed, and therefore, no heating coil energy demand is needed. The novel AHU used primary energy recovery as well as secondary one to utilize the return air energy and exergy. Through the first energy recovery unit, the return air exergy was recovered, while in the secondary heat exchanger, return air energy was recycled. Results showed that using the novel AHU leads to a reduction in energy consumption as well as the exergy losses. Three climate zones of A, B, and C were selected to assess the novel AHU performance. From the first law viewpoint, at zone B, using novel AHU has priority over other zones, while in the second law analysis, utilizing the novel AHU at zones B and C is more beneficial. Based on the first law analysis, owing to using novel AHU, energy consumption reduced up to 55.2% at Penang climate zone. Second law analysis revealed that utilizing the novel AHU decreased the irreversibility up to 51.4% in the Vancouver climate region.

An Investigation in Improving the Exhaust Management Process on Miller Cycle and Turbocompounding

2012 ◽  
Author(s):  
Thomas M. Lavertu ◽  
Roy J. Primus ◽  
Omowoleola C. Akinyemi
Keyword(s):  
Waste Heat ◽  
Process Variations ◽  
Exhaust Valve ◽  
Engine Fuel ◽  
Miller Cycle ◽  
Expansion Process ◽  
Combustion Gases ◽  
Power Turbine ◽  
Valve Opening ◽  
The Impact

A reduction in diesel engine fuel consumption at a constant emissions level can be achieved by various means. A power turbine as a means of waste heat recovery (i.e., turbocompounding) and altered intake valve closure timing (Miller cycle) are two such mechanisms. Each of these technologies act as a means of improving the expansion process of the combustion gases, requiring reduced fueling for the same work extraction. When these embodiments are typically implemented, the timing of the exhaust valve opening is maintained. However, optimization of the timing of the exhaust valve opening presents the potential for further improvement in the expansion process. Variations in the exhaust valve opening timing will be investigated for Miller and turbocompounding cycles as well as the combination of the two features. Results will be shown to quantify the impact these variations have in system efficiency. Second law analysis will be used to show how these variations in engine configurations impact individual loss mechanisms. Finally, comparisons will be made to show the relative differences between Miller cycle and turbocompounding with and without optimization of the exhaust valve timing.

Differences Between Second Law Analysis and Pinch Technology

1995 ◽  
Vol 117 (3) ◽  
pp. 186-191 ◽  
Author(s):  
D. A. Sama
Keyword(s):  
Heat Exchanger ◽  
Energy Recovery ◽  
Maximum Energy ◽  
Global Optimum ◽  
Second Law ◽  
Heat Exchanger Network ◽  
Second Law Analysis ◽  
Heat Exchanger Networks ◽  
Pinch Technology ◽  
Correct Design

The use of second law analysis to design a heat exchanger network is compared with the pinch technology approach. Differences between the two methods are identified and discussed in the light of claims made by practitioners of pinch technology. Second law insights are used to easily identify and correct design errors in a heat exchanger network, and to design maximum energy recovery networks. More importantly, it is found that use of the second law provides an understanding of the process which is totally absent in the pinch technology approach. The claims that pinch technology can find global optimum solutions, that only pinch technology can find maximum energy recovery heat exchanger networks, and that pinch technology is a form of second law analysis, are considered, discussed, and shown to be invalid.

Sign in / Sign up

Export Citation Format

Share Document