Control-Oriented Physics-Based NOX Emission Model for a Diesel Engine With Exhaust Gas Recirculation

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Saravanan Duraiarasan ◽  
Rasoul Salehi ◽  
Anna Stefanopoulou ◽  
Siddharth Mahesh ◽  
Marc Allain

Abstract Stringent NOX emission norm for heavy duty vehicles motivates the use of predictive models to reduce emissions of diesel engines by coordinating engine parameters and aftertreatment. In this paper, a physics-based control-oriented NOX model is presented to estimate the feedgas NOX for a diesel engine. This cycle-averaged NOX model is able to capture the impact of all major diesel engine control variables including the fuel injection timing, injection pressure, and injection rate, as well as the effect of cylinder charge dilution and intake pressure on the emissions. The impact of the cylinder charge dilution controlled by the engine exhaust gas recirculation (EGR) in the highly diluted diesel engine of this work is modeled using an adiabatic flame temperature predictor. The model structure is developed such that it can be embedded in an engine control unit without any need for an in-cylinder pressure sensor. In addition, details of this physics-based NOX model are presented along with a step-by-step model parameter identification procedure and experimental validation at both steady-state and transient conditions. Over a complete federal test procedure (FTP) cycle, on a cumulative basis the model prediction was more than 93% accurate.

Author(s):  
Khawar Mohiuddin ◽  
Minhoo Choi ◽  
Junkyu Park ◽  
Sungwook Park

Nozzle hydraulic flow rate is a critical parameter that affects the combustion process and plays a vital role in the production of emissions from a diesel engine. In this study, injection characteristics, such as normalized injection rate and spray tip penetration, were analyzed for different hydraulic flow rate injectors with the help of spray experiments. To further investigate the effects of hydraulic flow rate on engine-out particulate and gaseous emissions, engine experiments were performed for different values of hydraulic flow rate in multiple injectors. Various operating conditions and loading configurations were examined, and the effects of varying start of injection and exhaust gas recirculation rates for different hydraulic flow rates were analyzed. A separate Pegasor Particle Sensor (PPS-M) sensor was used to measure and collect data on the particle number, and an analysis was conducted to investigate the relation of particle number with hydraulic flow rate, injection timing, and exhaust gas recirculation rate. Results of the spray experiment exhibited a decreasing injection duration and increasing spray tip penetration with increasing hydraulic flow rate. Effect of hydraulic flow rate on combustion and emission characteristics were analyzed from engine experiment results. Least ignition delay was achieved using a smaller hole diameter, retarded injection timing, and lowest EGR%. Higher hydraulic flow rate with retarded injection timing and higher EGR% helped in reduction of NOx emissions and brake-specific fuel consumption, but particulate emissions were increased. Best particulate matter–NOx trade-off was achieved with lowest hydraulic flow rate.


2015 ◽  
Vol 813-814 ◽  
pp. 819-823 ◽  
Author(s):  
Pavan Bharadwaja Bhaskar ◽  
S. Srihari

In this study the effect on exhaust gases of a diesel engine fuelled by biodiesel and coupling Exhaust Gas Recirculation (EGR) has been done. EGR is a pre-treatment technique to trim down NOx from diesel engines as it is expected to reduce the flame temperature and the oxygen concentration in the combustion chamber. Fossil fuels so-called biodiesel is picked as the blending fuel. Existence of oxygen in Biodiesel aids complete combustion and anticipated to reduce CO and HC emissions. Exhaust Gas Recirculation technique can capably reduce the amount of NOx. EGR may tend to increase the CO and HC emissions, biodiesel which has higher oxygen content is blended to diesel so that it may compensate CO and HC emissions. The performance and emission characteristics of EGR along with biodiesel in a diesel engine are discussed.


2017 ◽  
Vol 19 (7) ◽  
pp. 758-773 ◽  
Author(s):  
Dheeraj B Gosala ◽  
Aswin K Ramesh ◽  
Cody M Allen ◽  
Mrunal C Joshi ◽  
Alexander H Taylor ◽  
...  

A large fraction of diesel engine tailpipe NOx emissions are emitted before the aftertreatment components reach effective operating temperatures. As a result, it is essential to develop technologies to accelerate initial aftertreatment system warm-up. This study investigates the use of early exhaust valve opening (EEVO) and its combination with negative valve overlap to achieve internal exhaust gas recirculation (iEGR), for aftertreatment thermal management, both at steady state loaded idle operation and over a heavy-duty federal test procedure (HD-FTP) drive cycle. The results demonstrate that implementing EEVO with iEGR during steady state loaded idle conditions enables engine outlet temperatures above 400 °C, and when implemented over the HD-FTP, is expected to result in a 7.9% reduction in tailpipe-out NOx.


2018 ◽  
Vol 29 (3) ◽  
pp. 372-391 ◽  
Author(s):  
M Krishnamoorthi ◽  
R Malayalamurthi

The threat of fossil fuel depletion and augmented environmental pollution caused by diesel fleets can be curbed by adopting suitable fuel and engine modifications. In the present work, effects of engine speed (r/min), injection timing, injection pressure and compression ratio on performance and emission characteristics of a compression ignition engine were investigated. The ternary test fuel of 65% diesel + 25% bael oil + 10% diethyl ether has been used, where the tests have been conducted at different charge inlet temperature and exhaust gas recirculation. All the experiments were conducted at the trade-off engine load that is 75% engine load. When the diesel engine operating with 320 K charge inlet temperature, brake thermal efficiency has been improved to 28.6%. Meanwhile reduced emission levels of carbon monoxide (0.025%) and hydrocarbon (12.3 ppm) were observed during the engine operation with 320 K charge inlet temperature and compression ratio of 18:1. The oxides of nitrogen have been reduced to 226 ppm at 16:1 compression ratio with 30% exhaust gas recirculation mode.


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