PCCI Control Authority of a Modern Diesel Engine Outfitted With Flexible Intake Valve Actuation

Author(s):  
Anup M. Kulkarni ◽  
Karla C. Stricker ◽  
Angeline Blum ◽  
Gregory M. Shaver

Premixed charge compression ignition (PCCI), an advanced mode combustion strategy, promises to simultaneously deliver the fuel efficiency of diesel combustion and the ultralow NOx emissions that usually require advanced exhaust aftertreatment. A flexible, computationally efficient, and whole engine simulation model for a 2007 6.7 l diesel engine with exhaust gas recirculation (EGR), variable geometry turbocharging (VGT), and common rail fuel injection was validated after extensive experimentation. This model was used to develop strategies for highly fuel-efficient and ultralow NOx emission PCCI. The primary aim of this modeling investigation is to determine the PCCI control authority present on a modern diesel engine outfitted with both conventional actuators (multipulse fuel injectors, EGR valve, and VGT) and flexible intake valve closure modulation, which dictates the effective compression ratio. The results indicate that early fuel injection coupled with ECR reduction and modest amounts of EGR yield a well-timed PCCI exhibiting 70%+ reductions in NOx with no fuel consumption penalty over a significant portion of the engine operating range.

Author(s):  
Fengjun Yan ◽  
Junmin Wang

Fueling control in Diesel engines is not only of significance to the combustion process in one particular cycle, but also influences the subsequent dynamics of air-path loop and combustion events, particularly when exhaust gas recirculation (EGR) is employed. To better reveal such inherently interactive relations, this paper presents a physics-based, control-oriented model describing the dynamics of the intake conditions with fuel injection profile being its input for Diesel engines equipped with EGR and turbocharging systems. The effectiveness of this model is validated by comparing the predictive results with those produced by a high-fidelity 1-D computational GT-Power engine model.


2009 ◽  
Vol 138 (3) ◽  
pp. 28-36
Author(s):  
Sathaporn CHUEPENG ◽  
Hongming XU ◽  
Athanasios TSOLAKIS ◽  
Mirosław WYSZYŃSKI ◽  
Jonathan HARLAND

The paper presents characterisations of nanoparticle number in exhaust gases from biodiesel blends (B30, 30% of RME by volume with ultra low sulphur diesel fuel, ULSD) combustion in a V6 diesel engine equipped with a common rail fuel injection system. The engine was operated on three steady-state test points extracted from the New European Driving Cycle without engine hardware or the engine management system (EMS) modification. A fast differential mobility spectrometer was used to determine particle number size distribution based on electrical mobility equivalent diameter. The distribution was dependent on the engine operating condition and the rate of exhaust gas recirculation (EGR). The particle size in the nucleation mode from B30 combustion with and without EGR is smaller than that of ULSD while giving higher number concentration for all engine operating conditions tested. However, in the accumulation mode with and without EGR, the smaller sizes and the lower total numbers from B30 combustion were observed. For both fuels, EGR shows insignificant changes to the primary particle size but noticeable increase in particle size and number in the accumulation mode. In overall, compared to the ULSD case, the B30 combustion reduced particle size and lowered total particle number in exhaust gas emitted from the engine with EGR.


2018 ◽  
Vol 172 (1) ◽  
pp. 59-63
Author(s):  
Jerzy KOWALSKI

The paper presents experimental research on a 4-stroke, 3-cylinder, turbocharged AL25/30 Diesel engine. Research consisted in investigating the effect of the geometry of the fuel injectors on the exhaust gas composition from the engine. During measurements, the engine was operated with a regulator characteristic of a load range from 40 kW to 280 kW, made by electric water resistance. The engine was mechanically coupled to the electric power generator. Three observations were made for each engine load, operating with fuel injectors of varying geometry. All considered types of injectors were installed on all engine cylinders. Mentioned injectors differed in the size of the nozzle holes diameters, holes numbers and angles measured between the holes axis. Engine performance data were recorded with a sampling time of 1 s. Cylinder pressure and fuel injection pressure on the front of each injector were collected also. The composition of the exhaust gas was measured using an electrochemical analyzer. According to the results, the change of fuel nozzle geometry results in a change in fuel spraying and evaporation and consequently changes in the course of the combustion process. The effect of this is the change of the composition of the exhaust gas.


Author(s):  
K. Subramanian ◽  
A. Kandaswamy ◽  
S. Mhahadevan

The two cylinder diesel engines are most demanding product in Indian market for power genset and tractor applications. But major task faced by engine manufacturers all over the world is to upgrade running engine designs with minimum and cost-effective modifications to meet the next level of emission norms. This saves the precious lead time and investments. In addition uncomplicated design has to be sustained as far as possible while improving emissions. Further the basic desires of the end user in off-road market are good response, transient performance, better low end torque, best fuel efficiency and smooth operation of the engine besides best in class reliability. Additional requirements needed to sustain the market with higher power to weight ratio and increased life of the engine. Henceforth turbocharging applications for off-road diesel engines are promising solution for enhancing rated power, low speed torque, transient performance, optimized fuel efficiency and engine downsizing. A trade-off is required to match some incompatible design issues like overall dimensions, cost, emissions control and performance in order to sustain the existing design. Future diesel engine emission standards will restrict vehicle emissions, particularly nitrogen oxides. In the present work, performance improvement for 1.7L, 2 cylinder in-line naturally aspirated diesel engine with mechanical fuel injection pump for off-road application is developed to contain all needs of the market. Design up-gradation of this engine for Tier IV is made with minimal design changes by optimal combinations of fuel injection equipment. This includes proper optimization of performance with improvements in nozzle geometry, change in injector end pressure. But due to the increased fuel flow rates for improving the engine performance as well as emission reduction, there is also a requirement for increased air flow. Henceforth in this study air flow rate is simulated and discussed for selection of turbocharger and intercooler. Further elaborate design and analysis study is also done on cooled exhaust gas recirculation system for exhaust gas cooling efficiency, Diesel Oxidation catalyst, Selective Catalytic Reduction /Lean NOx Trap substrate selection for reduced pressure drop and maximum retention time for exhaust gas to achieve Tier IV norms in turbocharged intercooled two cylinder engine.


2021 ◽  
Vol 3 (8) ◽  
Author(s):  
Prabhakara Rao Ganji ◽  
Rajesh Khana Raju Vysyaraju ◽  
Srinivasa Rao Surapaneni ◽  
B. Karuna Kumar

AbstractIn recent years, engine emissions have been one of the important problems which are of great concern. Hence, there is a growing need to develop engines with reduced emission. In the present study, Variable Compression Ratio diesel engine model has been validated by comparing the simulation results with the experimental. The study is aimed at analyzing the effect of compression ratio, exhaust gas recirculation, fuel injection pressure and start of injection on engine performance and emission characteristics. Using composite desirability technique, the engine parameters have been optimized to achieve lower NOx, soot and ISFC. The optimum combination has been observed at Compression ratio 17.52, Start of injection −30.1 °aTDC, Fuel injection pressure 736.06 bar and Exhaust gas recirculation 28.29%. ISFC, NOx and soot are reduced by 2.37%, 29.11% and 83.81% respectively. Higher Target Fuel Distribution Index indicates the improved mixture homogeneity for the optimized parameters.


Author(s):  
Varun Kumar Singh ◽  
Naushad Ahmad Ansari ◽  
Abhishek Sharma ◽  
Samsher Gautam ◽  
Manish Kumar ◽  
...  

Biodiesel such as linseed oil can be derived from the feedstock of vegetables without disturbing supplies of food and the ecosystem. An experimental and comparative analysis was carried out to explore the effect of exhaust gas recirculation (EGR) and fuel injection pressure (FIP) on the emissions and efficiency of a CRDI diesel engine fuelled with linseed biodiesel/diesel blend. The engine characteristics were calculated using variable EGR (up to 14%) and adjustment of the injection pressure (up to 600 bar) under various load conditions. Multiple regression models were generated to evaluate responses such as Carbon monoxide (CO), Oxides of Nitrogen (NOx), hydrocarbon (HC), Brake power (BP), and Brake thermal efficiency (BTE) using response surface methodology (RSM). For all blends, a combination of FIP and EGR was employed and their impact was evaluated by plotting response surface contour. In RSM, the desirability approach is used to maximize the performance and minimize the emissions parameters of the engine. Linseed/diesel blend ratio 18.3%, FIP 576.76 bar, EGR 7.07%, and load 5.76 kg were estimated to be optimum for the tested engine. From this methodology, it was found that the optimal value of BTE, BP, HC, NOx, and CO is 19.55%, 1.758 kW, 16.7534 ppm, 505.56 ppm, and 0.0676% respectively.


Author(s):  
Benjamin Haber ◽  
Junmin Wang

This paper presents a robust control approach to achieve an independent control authority over the intake manifold conditions of a medium-duty, V8, Diesel engine with the use of a complex air-path system. The intake manifold conditions in question include gas temperature, pressure, and oxygen mass fraction. The purpose of achieving such a high control authority over these intake manifold conditions is to explore the possibilities of extending the operating ranges of advanced combustion modes like low temperature diffusion combustion (LTDC), homogenous charge compression ignition (HCCI), and pre-mixed charge compression ignition (PCCI). Independent control of these air-path variables is made possible by using a dual-loop exhaust gas recirculation (EGR) system with a two-stage, variable geometry turbocharging (VGT) system. A multi-input-multi-output robust air-path controller was designed based on a control-oriented model identified using a high-fidelity GT-Power model of a medium-duty Diesel engine. Simulation results illustrate the effectiveness of the controller over a limited engine operating range.


2017 ◽  
Vol 20 (2) ◽  
pp. 194-202 ◽  
Author(s):  
Kalen R Vos ◽  
Gregory M Shaver ◽  
Xueting Lu ◽  
Cody M Allen ◽  
James McCarthy ◽  
...  

Valve train flexibility enables optimization of the cylinder-manifold gas exchange process across an engine’s torque/speed operating space. This study focuses on the diesel engine fuel economy improvements possible through delayed intake valve closure timing as a means to improve volumetric efficiency at elevated engine speeds via dynamic charging. It is experimentally and analytically demonstrated that intake valve modulation can be employed at high-speed (2200 r/min) and medium-to-high load conditions (12.7 and 7.6 bar brake mean effective pressure) to increase volumetric efficiency. The resulting increase in inducted charge enables higher exhaust gas recirculation fractions without penalizing the air-to-fuel ratio. Higher exhaust gas recirculation fractions allow efficiency improving injection advances without sacrificing NOx. Fuel savings of 1.2% and 1.9% are experimentally demonstrated at 2200 r/min for 12.7 and 7.6 bar brake mean effective pressure operating conditions via this combined strategy of delayed intake valve closure, higher exhaust gas recirculation fractions, and earlier injections.


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