Impact of Bore-to-Stroke Ratio Over Light-Duty DI Diesel Engine Performance, Emissions and Fuel Consumption: An Analytical Study Using 1D-CFD Coupled with DOE Methodology

Author(s):  
Alberto Vassallo ◽  
Venkatesh Gopalakrishnan ◽  
Stefano Arrigoni ◽  
Roberto Cavallo ◽  
Riccardo Turcato ◽  
...  
Author(s):  
Keshav S. Varde ◽  
Shubha K. Veeramachineni

There has been considerable interest in recent years in using blends of petroleum diesel and biodiesels in diesel engines. Some of the interests arise in making use of renewable fuels, or in reducing dependency on imported fossil fuels and, in some cases, to provide economic boost to agricultural industry. It is believed that substitution of a small amount of biodiesel for petroleum diesel can reduce the import of fuel and help in trade balance. Biodiesels, whether derived from vegetable oils or animal fat, have many properties that align with those of petroleum diesel. This makes biodiesel a good candidate for blending it in small quantities with petroleum diesel. Studies have shown biodiesel blends to work well in diesel engines. However, experimental investigations of biodiesel blends have shown some discrepancies in engine thermal efficiency and emissions of NOx. A combustion simulation model for diesel engine may help to understand some of the differences in engine performance when different fuels are used. This paper deals with an existing simulation model that was applied to a diesel engine operating on biodiesel blends. The model was a modified version of GT-Power that was specifically modified to fit the test engine. The model was calibrated using a single cylinder, naturally aspirated, DI diesel engine operating on ultra-low sulfur (ULSD) diesel. It was used to predict engine performance when operating on different blends of soy biodiesel and ULSD. The simulation utilized detailed physical and chemical properties of the blends to predict cylinder pressures, fuel consumption, and emissions of oxides of nitrogen (NOx). Comparison between predicted and experimental values showed good correlations. The predicted trends in fuel consumption, emissions of NOx and smoke showed comparable trends. The model allows the user to change fuel properties to assess the impact of variations in blend composition on exhaust emissions. This paper discusses comparisons between the predicted and experimental results and how fuel composition can possibly impact NOx emissions.


Author(s):  
Dimitrios T. Hountalas ◽  
Spiridon Raptotasios ◽  
Antonis Antonopoulos ◽  
Stavros Daniolos ◽  
Iosif Dolaptzis ◽  
...  

Currently the most promising solution for marine propulsion is the two-stroke low-speed diesel engine. Start of Injection (SOI) is of significant importance for these engines due to its effect on firing pressure and specific fuel consumption. Therefore these engines are usually equipped with Variable Injection Timing (VIT) systems for variation of SOI with load. Proper operation of these systems is essential for both safe engine operation and performance since they are also used to control peak firing pressure. However, it is rather difficult to evaluate the operation of VIT system and determine the required rack settings for a specific SOI angle without using experimental techniques, which are extremely expensive and time consuming. For this reason in the present work it is examined the use of on-board monitoring and diagnosis techniques to overcome this difficulty. The application is conducted on a commercial vessel equipped with a two-stroke engine from which cylinder pressure measurements were acquired. From the processing of measurements acquired at various operating conditions it is determined the relation between VIT rack position and start of injection angle. This is used to evaluate the VIT system condition and determine the required settings to achieve the desired SOI angle. After VIT system tuning, new measurements were acquired from the processing of which results were derived for various operating parameters, i.e. brake power, specific fuel consumption, heat release rate, start of combustion etc. From the comparative evaluation of results before and after VIT adjustment it is revealed an improvement of specific fuel consumption while firing pressure remains within limits. It is thus revealed that the proposed method has the potential to overcome the disadvantages of purely experimental trial and error methods and that its use can result to fuel saving with minimum effort and time. To evaluate the corresponding effect on NOx emissions, as required by Marpol Annex-VI regulation a theoretical investigation is conducted using a multi-zone combustion model. Shop-test and NOx-file data are used to evaluate its ability to predict engine performance and NOx emissions before conducting the investigation. Moreover, the results derived from the on-board cylinder pressure measurements, after VIT system tuning, are used to evaluate the model’s ability to predict the effect of SOI variation on engine performance. Then the simulation model is applied to estimate the impact of SOI advance on NOx emissions. As revealed NOx emissions remain within limits despite the SOI variation (increase).


Author(s):  
Jakub Lasocki

The World-wide harmonised Light-duty Test Cycle (WLTC) was developed internationally for the determination of pollutant emission and fuel consumption from combustion engines of light-duty vehicles. It replaced the New European Driving Cycle (NEDC) used in the European Union (EU) for type-approval testing purposes. This paper presents an extensive comparison of the WLTC and NEDC. The main specifications of both driving cycles are provided, and their advantages and limitations are analysed. The WLTC, compared to the NEDC, is more dynamic, covers a broader spectrum of engine working states and is more realistic in simulating typical real-world driving conditions. The expected impact of the WLTC on vehicle engine performance characteristics is discussed. It is further illustrated by a case study on two light-duty vehicles tested in the WLTC and NEDC. Findings from the investigation demonstrated that the driving cycle has a strong impact on the performance characteristics of the vehicle combustion engine. For the vehicles tested, the average engine speed, engine torque and fuel flow rate measured over the WLTC are higher than those measured over the NEDC. The opposite trend is observed in terms of fuel economy (expressed in l/100 km); the first vehicle achieved a 9% reduction, while the second – a 3% increase when switching from NEDC to WLTC. Several factors potentially contributing to this discrepancy have been pointed out. The implementation of the WLTC in the EU will force vehicle manufacturers to optimise engine control strategy according to the operating range of the new driving cycle.


2020 ◽  
pp. 146808742091880
Author(s):  
José Manuel Luján ◽  
Benjamín Pla ◽  
Pau Bares ◽  
Varun Pandey

This article proposes a method for fuel minimisation of a Diesel engine with constrained [Formula: see text] emission in actual driving mission. Specifically, the methodology involves three developments: The first is a driving cycle prediction tool which is based on the space-variant transition probability matrix obtained from an actual vehicle speed dataset. Then, a vehicle and an engine model is developed to predict the engine performance depending on the calibration for the estimated driving cycle. Finally, a controller is proposed which adapts the start-of-injection calibration map to fulfil the [Formula: see text] emission constraint while minimising the fuel consumption. The calibration is adapted during a predefined time window based on the predicted engine performance on the estimated cycle and the difference between the actual and the constraint on engine [Formula: see text] emissions. The method assessment was done experimentally in the engine test set-up. The engine performace using the method is compared with the state-of-the-art static calibration method for different [Formula: see text] emission limits on real driving cycles. The online implementation of the method shows that the fuel consumption can be reduced by 3%–4% while staying within the emission limits, indicating that the estimation method is able to capture the main driving cycle characterstics.


2019 ◽  
Vol 8 (4) ◽  
pp. 4048-4052

Biodiesel, a derivative of vegetable oils and animal fats, is used nowadays as an alternative renewable and sustainable fossil fuel. In this work, the investigation of manufacture, characterization, and results of biodiesel blends are carried out using two important feedstock’s, sunflower oil and ricebran oil on engines. For the collective advantageous of sunflower oil and ricebran oil, the two biodiesels are combined together and the mixture is analysed to assess the engine performance and emission characteristics. NaOH catalyzed transesterification process is used for producing the Biodiesels A 4.4 kW, four-stroke, single-cylinder and direct fuel injection diesel engine is used for measuring physic-chemical with full load and varying speed conditions and using the specifications of ASTM D6751 standard, the properties are compared. It is observed that the Biodiesel mixtures produce a low brake torque and high brake-specific fuel consumption (BSFC) in addition to the reduction of CO and HC emissions. NOx, however, is reduced considerably with the improvement of brake thermal efficiency. The Performance analysis indicates that the mixture of sunflower oil and ricebran oil improves performance and emission characterizes over sunflower oil and ricebran oil biodiesel when they are unmixed..


Fuel ◽  
2019 ◽  
Vol 235 ◽  
pp. 832-837 ◽  
Author(s):  
R. Dhanasekaran ◽  
S. Ganesan ◽  
B. Rajesh Kumar ◽  
S. Saravanan

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