Effect of Exhaust System Design on Engine Performance

1980 ◽  
Author(s):  
Tim G. Adams
Keyword(s):  
System Design ◽  
Engine Performance ◽  
Exhaust System

Using gas dynamic models to improve exhaust system design for large-bore, two-stroke engines

2020 ◽  
pp. 146808742094402
Author(s):  
Abdullah U Bajwa ◽  
Mark Patterson ◽  
Timothy J Jacobs
Keyword(s):  
Gas Exchange ◽  
System Design ◽  
Dynamic Models ◽  
Cross Flow ◽  
Engine Performance ◽  
Exhaust System ◽  
Thermodynamic Efficiency ◽  
Trade Off ◽  
Exhaust Port ◽  
Scavenging Efficiency

It is vital to have accurate predictions of the gas exchange behavior of an engine in order to reliably study engine performance and emissions using engine simulation models. There are a multitude of factors, both upstream and downstream of the engine cylinder, which influence its gas exchange characteristics. Quite often these influences are interconnected in a non-linear manner that results in complicated feedback loops, which can introduce significant errors in the computed thermodynamic state of the post-breathing cylinder mixture. The effects of such bi-directional movement of pressure pulses are particularly pronounced in two-stroke engines. This study investigates the importance of exhaust system design on the scavenging characteristics of a piston-scavenged, cross-flow, two-stroke engine. A validated one-dimensional predictive model is used to study the effects of changing the exhaust port timing, exhaust system length, and exhaust port efficiency on the breathing performance of the engine, along with the consequent effects on the thermal efficiency and NOx emissions. Exhaust pressure waves and mass flows across ports are used to understand and explain the observed changes. The results show that while making design changes, thermodynamic efficiency considerations can act as a barrier to improving the scavenging efficiency of the engine; in addition, a trade-off between the two has to be considered in the design process to meet engine performance targets. The effects of such a trade-off on the NOx production are analyzed and two exhaust system modifications are discussed.

scholarly journals Preliminary Design Framework for the Power Gearbox in a Contra-Rotating Open Rotor

2020 ◽  
Author(s):  
Diana G. San Benito Pastor ◽  
Devaiah Nalianda ◽  
Vishal Sethi ◽  
Ron Midgley ◽  
Andrew Rolt ◽  
...  
Keyword(s):  
System Design ◽  
Load Capacity ◽  
Engine Performance ◽  
Maximum Load ◽  
Transmission System ◽  
Published Data ◽  
Planetary Gearbox ◽  
Open Rotor ◽  
Parametric Analyses ◽  
The Impact

Abstract This study introduces an innovative approach to sizing a differential planetary gearbox for a counter-rotating open rotor application. An updated methodology is proposed for the design of maximum load capacity gears based on the power transmitted, durability and space-envelope requirements of the application. The reported methodology has been validated by comparing the results to published data, demonstrating a maximum difference of 0.6% in geometry. Parametric analyses have also been performed to assess the impact of the design assumptions on gearbox dimensional trends. The proposed methodology enables the assessment of the impact of the preliminary transmission system design on engine performance and general arrangement. The characteristics of the gearset lead to an unequal torque split between output shafts (i.e. the propeller shafts). Given the design assumptions made, the study indicates that valid torque ratios would lie between 1.1 and 1.33. The impact of the torque ratio on the size of the gearbox has been analysed for equal rotational speeds and for different speeds between the output shafts. The study established that the transmission system design needs to be considered prior to selection of the torque ratio at engine design level.

Model Based Design and Optimization for Large Bore Engines: Some Industrial Case Studies

2017 ◽  
Author(s):  
Prashant Srinivasan ◽  
Sanketh Bhat ◽  
Manthram Sivasubramaniam ◽  
Ravi Methekar ◽  
Maruthi Devarakonda ◽  
...  
Keyword(s):  
System Design ◽  
Case Studies ◽  
Control Strategy ◽  
Internal Combustion Engines ◽  
Cost Optimization ◽  
Engine Performance ◽  
Design And Optimization ◽  
Model Based ◽  
Performance Requirements ◽  
Engine Design

Large bore reciprocating internal combustion engines are used in a wide variety of applications such as power generation, transportation, gas compression, mechanical drives, and mining. Each application has its own unique requirements that influence the engine design & control strategy. The system architecture & control strategy play a key role in meeting the requirements. Traditionally, control design has come in at a later stage of the development process, when the system design is almost frozen. Furthermore, transient performance requirements have not always been considered adequately at early design stages for large engines, thus limiting achievable controller performance. With rapid advances in engine modeling capability, it has now become possible to accurately simulate engine behavior in steady-states and transients. In this paper, we propose an integrated model-based approach to system design & control of reciprocating engines and outline ideas, processes and real-world case studies for the same. Key benefits of this approach include optimized engine performance in terms of efficiency, transient response, emissions, system and cost optimization, tools to evaluate various concepts before engine build thus leading to significant reduction in development time & cost.

scholarly journals Development of a New-Concept Supercharged Single-Cylinder Engine for Race Car

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3694
Author(s):  
Chuanxue Song ◽  
Gangpu Yu ◽  
Shuai Yang ◽  
Ruoli Yang ◽  
Yi Sun ◽  
...  
Keyword(s):  
Integrated Circuit ◽  
Performance Test ◽  
Test Bench ◽  
Dynamic Performance ◽  
Engine Performance ◽  
Exhaust System ◽  
Bench Test ◽  
Single Cylinder ◽  
Race Car ◽  
Single Cylinder Engine

This article summarises the development and experience of the Formula Student race car engine from 2018. According to the technical rules of Formula Student after the change in 2017, this engine adopts a new design concept, employs a 690-mL single-cylinder engine as the base, and applies ‘response enhancement technology’ with supercharging as the core to achieve a high-power output, a wide high-torque range and an excellent response capability. During the development, various studies on the dynamic performance of the vehicle and the engine were conducted, including vehicle dynamics analysis and track simulation, parameter matching of the supercharger and the engine, control strategy design, and the intake and exhaust system design. This research builds a supercharger air flow and efficiency test bench and an engine performance test bench. Test results show that the developed engine can output 122% of the original power and 120% of the original torque with a 20-mm diameter intake restrictor. Compared with previous generation race cars with a turbocharged four-cylinder engine, the new race car‘s 0–100 km/h acceleration time is shortened by 0.2 s, the torque response time under typical condition is shortened by 80%, and the lap time of the integrated circuit is reduced by 7%.

Paper 4: The Effect of Combustion Chamber Shape and Other Engine Design Factors on Exhaust Emissions

1968 ◽  
Vol 183 (5) ◽  
pp. 133-144 ◽  
Author(s):  
P. L. Dartnell ◽  
C. L. Goodacre ◽  
P. V. Lamarque
Keyword(s):  
Combustion Chamber ◽  
Engine Performance ◽  
Exhaust System ◽  
Exhaust Emissions ◽  
Intake Manifold ◽  
Valve Timing ◽  
Mixture Formation ◽  
Engine Design ◽  
Basic Engine ◽  
Design Factors

A Heron combustion chamber engine of 2 litre capacity has been utilized to investigate the effect of combustion chamber shape, increased mixture movement, valve timing, mixture formation, and reaction in the exhaust system on engine performance and level of exhaust emissions using the seven-mode U.S. Federal cycle. Such factors as carburettor weakening and limitation of intake manifold vacuum during overrun have been included in this investigation, and it has been shown that it is possible to reduce exhaust emissions and also satisfy the current U.S. requirements with an engine giving acceptable performance, improved economy, and unaffected reliability. Much of the information reported may be negative in terms of improvement to exhaust emissions by detailed engine design. Nevertheless, some positive conclusions have been reached as a result of this work, and it is hoped that this will draw forth more informed discussion than the authors have been able to assemble from the work attempted with one basic engine.

scholarly journals Artificial Intelligence for the Prediction of Exhaust Back Pressure Effect on the Performance of Diesel Engines

2020 ◽  
Vol 10 (20) ◽  
pp. 7370
Author(s):  
Vlad Fernoaga ◽  
Venetia Sandu ◽  
Titus Balan
Keyword(s):  
Artificial Intelligence ◽  
Engine Performance ◽  
Exhaust System ◽  
Hardware Acceleration ◽  
Back Pressure ◽  
Smart Devices ◽  
Effective Power ◽  
Steady State Operation ◽  
Complete Dataset ◽  
And Performance

The actual trade-off among engine emissions and performance requires detailed investigations into exhaust system configurations. Correlations among engine data acquired by sensors are susceptible to artificial intelligence (AI)-driven performance assessment. The influence of exhaust back pressure (EBP) on engine performance, mainly on effective power, was investigated on a turbocharged diesel engine tested on an instrumented dynamometric test-bench. The EBP was externally applied at steady state operation modes defined by speed and load. A complete dataset was collected to supply the statistical analysis and machine learning phases—the training and testing of all the AI solutions developed in order to predict the effective power. By extending the cloud-/edge-computing model with the cloud AI/edge AI paradigm, comprehensive research was conducted on the algorithms and software frameworks most suited to vehicular smart devices. A selection of artificial neural networks (ANNs) and regressors was implemented and evaluated. Two proof-of concept smart devices were built using state-of-the-art technology—one with hardware acceleration for “complete cycle” AI and the other with a compact code and size (“AI in a nut-shell”) with ANN coefficients embedded in the code and occasionally offline “statistical re-calibration”.

Exhaust System Gas-Dynamics in Internal Combustion Engines

2006 ◽  
Author(s):  
R. Pearson ◽  
M. Bassett ◽  
P. Virr ◽  
S. Lever ◽  
A. Early
Keyword(s):  
Gas Dynamics ◽  
Internal Combustion Engines ◽  
Engine Performance ◽  
Exhaust System ◽  
Combustion Engines ◽  
Cycle Simulation ◽  
Model Following ◽  
Analytical Tools ◽  
Empirical Approaches ◽  
Engine Cycle

The sensitivity of engine performance to gas-dynamic phenomena in the exhaust system has been known for around 100 years but is still relatively poorly understood. The nonlinearity of the wave-propagation behaviour renders simple empirical approaches ineffective, even in a single-cylinder engine. The adoption of analytical tools such as engine-cycle-simulation codes has enabled greater understanding of the tuning mechanisms but for multi-cylinder engines has required the development of accurate models for pipe junctions. The present work examines the propagation of pressure waves through pipe junctions using shock-tube rigs in order to validate a computational model. Following this the effects of exhaust-system gas dynamics on engine performance are discussed using the results from an engine-cycle-simulation program based on the equations of one-dimensional compressible fluid flow.

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