Effects of Late Intake Valve Closing on Four Stroke Gasoline Engines

Volume 1 ◽  
2004 ◽  
Author(s):  
G. B. Parvate-Patil ◽  
H. Hong ◽  
B. W. Gordon
Keyword(s):  
Fluid Flow ◽  
Fuel Consumption ◽  
Specific Fuel Consumption ◽  
Simulation Program ◽  
Intake Valve ◽  
Power Study ◽  
Gasoline Engines ◽  
Cycle Simulation ◽  
Engine Cycle

The objective of this paper is to the study effects of Late Intake Valve Closing (LIVC), and how it affects the in-cylinder fluid flow for four stroke gasoline engines. Further investigation of LIVC has been performed with the help of an engine cycle simulation program (GT-Power). Study shows that LIVC is beneficial for reduction of pumping losses, which may reduce the break specific fuel consumption (BSFC) of the engine. In this paper, a simulation of LIVC was achieved by retarding the timing of the solenoid actuated intake valve.

A numerical procedure for the calibration of a turbocharged spark-ignition variable valve actuation engine at part load

2016 ◽  
Vol 18 (8) ◽  
pp. 810-823 ◽  
Author(s):  
Fabio Bozza ◽  
Vincenzo De Bellis ◽  
Luigi Teodosio
Keyword(s):  
Fuel Consumption ◽  
Spark Ignition ◽  
Specific Fuel Consumption ◽  
Brake Specific Fuel Consumption ◽  
Valve Closure ◽  
Intake Valve ◽  
Part Load ◽  
Variable Valve Actuation ◽  
Variable Valve ◽  
Valve Actuation

Referring to spark-ignition engines, the downsizing, coupled to turbocharging and variable valve actuation systems are very common solutions to reduce the brake-specific fuel consumption at low-medium brake mean effective pressure. However, the adoption of such solutions increases the complexity of engine control and management because of the additional degrees of freedom, and hence results in a longer calibration time and higher experimental efforts. In this work, a twin-cylinder turbocharged variable valve actuation spark-ignition engine is numerically investigated by a one-dimensional model (GT-Power™). The considered engine is equipped with a fully flexible variable valve actuation system, realizing both a common full-lift strategy and a more advanced early intake valve closure strategy. Refined sub-models are used to describe turbulence and combustion processes. In the first stage, one-dimensional engine model is validated against the experimental data at full and part load. The validated model is then integrated in a multipurpose commercial optimizer (modeFRONTIER™) with the aim to identify the engine calibration that minimizes brake-specific fuel consumption at part load. In particular, the decision parameters of the optimization process are the early intake valve closure angle, the throttle valve opening, the turbocharger setting and the spark timing. Proper constraints are posed for intake pressure in order to limit the gas-dynamic noise radiated at the intake mouth. The adopted optimization approach shows the capability to reproduce with good accuracy the experimentally identified calibration. The latter corresponds to the numerically derived Pareto frontier in brake mean effective pressure–brake specific fuel consumption plane. The optimization also underlines the advantages of an engine calibration based on a combination of early intake valve closure strategy and intake throttling rather than a purely throttle-based calibration. The developed automatic procedure allows for a ‘virtual’ calibration of the considered engine on completely theoretical basis and proves to be very helpful in reducing the experimental costs and the engine time-to-market.

Engine Performance Characteristics Under Controlled Engine Temperature With Variable Operating Parameters

2011 ◽  
Author(s):  
R. K. Mandloi ◽  
A. Rehman
Keyword(s):  
Fuel Consumption ◽  
Engine Speed ◽  
Engine Performance ◽  
Specific Fuel Consumption ◽  
Exhaust Emission ◽  
Full Potential ◽  
Emission Standard ◽  
Engine Load ◽  
Gasoline Engines ◽  
Brake Power

In the present scenario, the designs of S I engine being used in automotives by various manufacturers are not properly suitable to Indian climate condition. India is among those tropical countries where the variation in the temperature is having very vast range i.e. from 0°C to 50°C in various regions of the country. Looking in to this vast varying temperature range, it is very difficult to say that which temperature is most suited for operating condition of engines and will give the best performance levels as far as SFC & BP is concerned. In this work, it has been tried to investigate the best option to run the SI engine and simultaneously to maintain the emission norms. Today research and development in the field of gasoline engines have to face double challenge; on one hand, fuel consumption has to be reduced, while on the other hand, even more stringent emission standard have to be fulfilled. The development of engines with its complexity of in-cylinder process requires modern developed tools to exploit the full potential in order to reduce fuel consumption. There are many strategies for improving fuel economy and reducing exhaust emission HC & CO. The experimental study is carried out on a three cylinders, four stroke, petrol, carbureted, water cooled engine test rig connected to eddy current type dynamometer. The objective of this work was to examine engine performance parameter i.e. specific fuel consumption (SFC), brake power (BP) and also exhaust emission on Varying Engine Temperature at 50, 60, 70, 80° C and at an engine speed of 1500, 2000, 2500 rpm with respect to engine load 6, 9, 12 kg. The results are shown by various graphs with effect of engine temperature on specific fuel consumption, brake power, engine speed, engine load and emission levels of Nox, HC, CO for gasoline and LPG to improve fuel consumption.

Intercooler Parametric Analysis for the IRA Engine Cycle Performance Augmentation

2021 ◽  
Author(s):  
Emmanouil Alexiou ◽  
Zinon Vlahostergios ◽  
Christina Salpingidou ◽  
Fabian Donus ◽  
Dimitrios Misirlis ◽  
...  
Keyword(s):  
Combustion Chamber ◽  
Fuel Consumption ◽  
Heat Exchangers ◽  
High Efficiency ◽  
Specific Fuel Consumption ◽  
Cycle Performance ◽  
Tubular Heat Exchanger ◽  
Aero Engine ◽  
Pressure Compressor ◽  
Engine Cycle

Abstract Aiming in the direction of designing high efficiency aircraft engines, various concepts have been developed in recent years, among which is the concept of the intercooled and recuperative aero engine (IRA engine). This concept is based on the use of a system of heat exchangers (recuperator) mounted inside the hot-gas exhaust nozzle, as well as a system of heat exchangers (intercooler) mounted between the intermittent-pressure compressor (IPC) and the high-pressure compressor (HPC) compressor modules. Through the operation of the system of recuperator module, the heat from the exhaust gas, downstream the LP turbine of the aero engine is driven back to the combustion chamber. Thus, the preheated air enters the engine combustion chamber with increased enthalpy, providing higher combustion efficiency and consequently reduced thrust specific fuel consumption (TSFC) and low-level emissions. Additionally, by integrating the intercooler module between the compressor stages of the aero engine, the compressed air is cooled, leading to less required compression work to reach the compressor target pressure and significant improvements can be achieved in the overall engine efficiency and the specific fuel consumption hence, contributing to the reduction of CO2 and NOx emissions. The present work is focused on the optimization of the performance characteristics of an intercooler specifically designed for aero engine applications, working cooperatively with a novel design recuperator module targeting the reduction of specific fuel consumption and taking into consideration aero engine geometrical constraints and limitations for two separate operating scenarios. The intercooler design was based on the elliptically profiled tubular heat exchanger which was developed and invented by MTU Aero Engines AG. For the specific fuel consumption investigations, the Intercooled Recuperated Aero engine cycle that combines both intercooling and recuperation was considered. The optimization was performed with the development of an intercooler surrogate model, capable to incorporate major geometrical features. A large number of intercooler design scenarios was assessed, in which additional design criteria and constraints were applied. Thus, a significantly large intercooler design space was covered resulting to the identification of feasible designs providing beneficial effect on the Intercooled Recuperated Aero engine performance leading to reduced specific fuel consumption, reduced weight and extended aircraft range.

Exergy analysis of a turboprop engine at different flight altitude and speeds using novel consideration

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Ali Dinc ◽  
Yousef Gharbia
Keyword(s):  
Fuel Consumption ◽  
Thermal Efficiency ◽  
Exergy Efficiency ◽  
Specific Fuel Consumption ◽  
Flight Altitude ◽  
Fuel Flow ◽  
Turboprop Engine ◽  
Shaft Power ◽  
Two Parameters ◽  
The Relationship

Abstract In this study, exergy efficiency calculations of a turboprop engine were performed together with main performance parameters such as shaft power, specific fuel consumption, fuel flow, thermal efficiency etc., for a range of flight altitude (0–14 km) and flight speeds (0–0.6 Mach). A novel exergy efficiency formula was derived in terms of specific fuel consumption and it is shown that these two parameters are inversely proportional to each other. Moreover, a novel exergy efficiency and thermal efficiency relation was also derived. The relationship showed that these two parameters are linearly proportional to each other. Exergy efficiency of the turboprop engine was found to be in the range of 23–33%. Thermal efficiency of the turboprop engine was found to be around 25–35%. Exergy efficiency is higher at higher speeds and altitude where the specific fuel consumption is lower. Conversely, exergy efficiency of the engine is lower for lower speeds and altitude where the specific fuel consumption is higher.

Two-Stroke Marine Diesel Engine Variable Injection Timing System Performance Evaluation and Optimum Setting for Minimum Fuel Consumption at Acceptable NOx Levels

2014 ◽  
Author(s):  
Dimitrios T. Hountalas ◽  
Spiridon Raptotasios ◽  
Antonis Antonopoulos ◽  
Stavros Daniolos ◽  
Iosif Dolaptzis ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Fuel Consumption ◽  
Engine Performance ◽  
Operating Conditions ◽  
Specific Fuel Consumption ◽  
Injection Timing ◽  
Nox Emissions ◽  
Pressure Measurements ◽  
Cylinder Pressure ◽  
Start Of Injection

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).

Characteristics of Water-in-Diesel Emulsions in a Single Cylinder Compression Ignition Engine

2014 ◽  
Author(s):  
Teja Gonguntla ◽  
Robert Raine ◽  
Leigh Ramsey ◽  
Thomas Houlihan
Keyword(s):  
Fuel Consumption ◽  
Direct Injection ◽  
Engine Performance ◽  
Operating Conditions ◽  
Specific Fuel Consumption ◽  
Brake Specific Fuel Consumption ◽  
Compression Ignition Engine ◽  
Oil Emulsion ◽  
Single Cylinder ◽  
Performance And Emission

The objective of this project was to develop both engine performance and emission profiles for two test fuels — a 6% water-in-diesel oil emulsion (DOE-6) fuel and a neat diesel (D100) fuel. The testing was performed on a single cylinder, direct-injection, water-cooled diesel engine coupled to an eddy current dynamometer. Output parameters of the engine were used to calculate Brake Specific Fuel Consumption (BSFC) and Engine Efficiency (η) for each test fuel. DOE-6 fuels generated a 24% reduction in NOX and a 42% reduction in Carbon Monoxide emissions over the tested operating conditions. DOE-6 fuels presented higher ignition delays — between 1°-4°, yielded 1%–12% lower peak cylinder pressures and produced up to 5.5% lower exhaust temperatures. Brake Specific Fuel consumption increased by 6.6% for the DOE-6 fuels as compared to the D100 fuels. This project is the first research done by a New Zealand academic institution on water-in-diesel emulsion fuels.

An Improvement of Part Load Performance of Diesel Engines Operating at Constant Speed Conditions

1994 ◽  
Vol 208 (1) ◽  
pp. 21-25 ◽  
Author(s):  
A A Abdel-Rahman ◽  
M K Ibrahim ◽  
A A Said
Keyword(s):  
Fuel Consumption ◽  
Diesel Engines ◽  
Petroleum Refining ◽  
Specific Fuel Consumption ◽  
Constant Speed ◽  
Maximum Pressure ◽  
Brake Specific Fuel Consumption ◽  
Part Load ◽  
Generating Sets ◽  
In Series

This paper discusses the possibility of improving the part load performance of diesel electric turbocharged engines operating at constant speed conditions. A sequential turbocharged system is proposed, where the compressors are connected In series. The study focused on two turbocharged diesel–electric generating sets existing at Ameria Petroleum Refining Company in Alexandria, Egypt. The results of the prediction showed that, at part load, both the maximum pressure and temperature were increased, and the brake specific fuel consumption was reduced considerably (by about 10 per cent).

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