Impact of Using Low Thermal Mass Turbine Housing on Exhaust Temperature with Implication on Aftertreatment Warm-Up Benefit for Emissions Reduction

2020 ◽  
Author(s):  
Shakti Saurabh ◽  
Chunyi Xia ◽  
Akram Khatib ◽  
Neal Wallace ◽  
Michael Ruth ◽  
...  
Keyword(s):  
Emissions Reduction ◽  
Thermal Mass ◽  
Warm Up ◽  
Exhaust Temperature ◽  
Turbine Housing

Exhaust valve phasing controllers for cold start NOx emissions reduction in heavy duty diesel engines

2021 ◽  
pp. 146808742199651
Author(s):  
Rasoul Salehi ◽  
Robert J Middleton
Keyword(s):  
Operating Conditions ◽  
Exhaust Valve ◽  
Emissions Reduction ◽  
Drive Cycle ◽  
Test Drive ◽  
Rule Based ◽  
Warm Up ◽  
Model Based ◽  
Predictive Controller ◽  
Scr System

In this paper, early exhaust valve opening (EVO) is applied to a diesel engine for fast warm up of the selective catalytic reduction (SCR) system with the ultimate goal of tailpipe NOx emissions reduction. By advancing EVO from top dead center, the exhaust gas temperature increases and the exhaust flow reduces, influencing the enthalpy available to warm up the SCR, and the engine-out NOx emissions increase or decrease depending on the engine’s operating conditions. Therefore, proper management of EVO is required to ensure that (1) engine-out NOx emissions do not increase when the SCR catalyst is cold; (2) heat transfer to the SCR increases and it warms up faster than the baseline operation (without EVO phasing); and (3) fuel consumption increase is minimal. A novel model predictive controller (MPC) is proposed for this application, assuming a limited preview of the drive cycle is available. For the MPC, an optimization objective function is applied such that a sequential warm up strategy can be implemented for the aftertreatment system catalysts. Using this technique, the prediction horizon for effective thermal management of the slow SCR system is reduced. In addition, a rule-based logic is offered as an alternative to the predictive controller to calculate the EVO trajectory with less computational power. Observations based on optimization problems solved by dynamic programing (DP) were used to develop the rule-based controller. Both the rule-based logic and model-based MPC are tested with a detailed high fidelity one-dimensional model in a model-in-the-loop simulator. Results indicate the potential of an EVO phasing system with the proposed controllers to reduce tailpipe NOx by 10% and 25% for the world harmonized transient cycle (WHTC) and federal test procedure (FTP), respectively. The rule-based controller has been found to be sensitive to the test drive cycle while the model based MPC shows a consistent performance, that is, independent of the test trajectory.

The Experimental Study of the Inner Insulated Turbocharger Turbine

2020 ◽  
Author(s):  
Yang Liu ◽  
Misan Madamedon ◽  
Richard Burke ◽  
Jürgen Werner
Keyword(s):  
Heat Transfer ◽  
Emission Reduction ◽  
Exhaust Aftertreatment ◽  
Outlet Temperature ◽  
Turbocharged Diesel Engine ◽  
Warm Up ◽  
Turbine Housing ◽  
Aftertreatment Systems ◽  
Engine Systems ◽  
Test Result

Abstract For turbocharged diesel engine systems, emission reduction is the most significant challenge that manufacturers should overcome. In response to the emission reduction challenge most turbocharged diesel engine systems have adopted complex exhaust aftertreatment systems. Due to the current stringent emission regulation, exhaust aftertreatment system nowadays needs to discover new methods to increase its efficiency of pollution conversion. Increasing the inlet temperature of aftertreatment systems can help reduce the light-off time. Whilst most methods to do this involve increases in fuel consumption (retarded injection, engine throttling), insulating the turbocharger turbine to reduce heat loss does not have this drawback. This paper presents a simulation and experimental study the performance of a turbocharger with inner insulated turbine housing, compared with the standard turbocharger (same turbine wheel without inner insulation). Both turbochargers were tested on an engine gas stand test rig with a 2.2L prototype engine acting as an exhaust gas generator. In a steady state condition, the insulated turbocharger can achieve 5 to 14K higher turbine outlet temperature depending on the engine speed and load conditions. Three types of transient tests were implemented to investigate turbocharger turbine heat transfer performance. The test plan was designed to the engine warm up, step load transient, WLTC cycle and simplified RDE cycle. In the engine warm up test result, the temperature drops between the turbine inlet and outlet was reduced by 4K with the insulated turbine housing. In the results of step load transient test, the turbine with insulated turbine housing was observed to get only 4K temperature benefit but with 2kRPM higher turbocharger speed under the same turbocharger inlet and outlet boundary conditions. In the WLTC cycle test result, turbocharger average speed was increased by 0.8kRPM due to the increased enthalpy of the turbine with insulation, the turbine outlet temperature has an average 1.7K improvement. The experimental results were used to parameterise a simple, 1D, lumped capacitance model which could predict similar aerodynamic behaviour of the two turbines (turbine housing insulated and non-insulated). However, current model has less accuracy in highly transient process as the heat transfer coefficients are unchangeable in each process. The turbine outlet temperature got at most 10K error for the turbine with non-insulated housing and 13K error for the insulated one. The model was shown to over-estimate the benefits of the inner insulation for 1K in turbine outlet temperature.

The effects of psyching-up and a passive warm-up on muscular strength and fatigue

2007 ◽  
Author(s):  
David Tod ◽  
Jonathan Baker ◽  
Michael McGuigan
Keyword(s):  
Muscular Strength ◽  
Warm Up
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