Machine Learning–Based Prediction and Analysis of Engine Performance for a Direct‐Port Injection Compressed Natural Gas Fueled Engine

The paper put forwards and designs high-pressure common-rail fuel injection system based on technology characteristics of in-cylinder and direct-injection compressed natural gas (CNG) engine, and a model of high-pressure common-rail for CNG engine is built with AMEsim software. For researching the dynamic characteristics of high-pressure common-rail system of a CNG engine, the influences of speed, common rail volume, aspect ratio and rail pressure on pressure fluctuation amplitude were synthetically analyzed. At the controlling aim of pressure fluctuation amplitude, a compound controller based on cerebellar model articulation controller(CMAC) neural network and PD is presented and finally the model of control system was built with MATLAB/Simulink. The co-simulation results show that the simulation system can simulate the actual working process of the high-pressure common-rail system for CNG engine and that the used control strategy can meet the demands of flexible control of fuel injection quantity and pressure. Accordingly, the system lays the foundation for researching high-pressure direct injection CNG engine.

<div class="section abstract"><div class="htmlview paragraph">Today, passenger car makers around the world are striving to meet the increasing demand for fuel economy, high performance, and silent engines. Corporate Average Fuel Economy (CAFE) regulations implemented in India to improve the fuel efficiency of a manufacturer's fleet of vehicles. CAFE goal is to reduce fuel consumption and, by extension, the emissions that contribute to climate change. CNG (Compressed Natural Gas) engines offer several advantages that help manufacturers meet and exceed these standards.</div><div class="htmlview paragraph">The demand for CNG vehicles has surged exponentially in recent years, CNG engine better Fuel efficiency and advantage in CAFÉ norms make good case for OEM & Customer to use more CNG vehicle. CNG is dry fuel compared to gasoline. These dry fuels lack lubricating properties, unlike conventional fuels like petrol, diesel and biofuels, which are wet and liquid. Consequently, the operations and failures associated with these fuels differ. The materials and designs of engine parts, such as fuel lines, ECU, exhaust valves, and cylinder heads, vary depending on the fuel used.</div><div class="htmlview paragraph">In CNG engine most challenging issue is leakage at Valve seat and Valve face interface causing unstable combustion and power drop. This study discusses the countermeasures adopted to address the high valve face, Valve guide and valve seat wear in cylinder heads and engine valves. The investigation focuses on material, design, and manufacturing process improvements specially for Exhaust valve, supported by part-level and vehicle-level validation and testing for CNG exhaust valves and cylinder heads.</div></div>

Numerical analysis of performance, combustion, and emission characteristics of PFI gasoline, PFI CNG, and DI CNG engine

Effect of compression ratio on engine knock, performance, combustion and emission characteristics of a bi-fuel CNG engine

Natural gas is well-suited as a fuel in the transport sector. Due to its excellent combustion characteristics, engines operating with compressed natural gas (CNG) reach high efficiency, especially if operated at lean conditions. However, CNG engine research mainly focusses on stoichiometric conditions in order to use a three-way catalytic converter for the exhaust gas after treatment system. With the objective to explore the potential of CNG engines operated at lean conditions, a turbo-charged CNG engine with high com-pression ratio is developed and optimized for lean operation. In order to increase the ignition energy, the CNG engine is equipped with scavenged pre-chambers. A specific control structure is developed, which allows to operate the engine at a pre-defined (lean) air-to-fuel ratio. Further functionalities such as the combustion placement control and algorithms to estimate the conditions inside of the pre-chamber are implemented. The first part of this paper describes this engine control structure, which is specifically developed for the lean-burn CNG engine. In the second part, the effects of pre-chamber scavenging on engine performance criteria such as the combustion stability, engine efficiency or engine emissions are analyzed. With the objective to use pre-chamber scavenging to improve engine performance, a scavenging feed-back control strategy is proposed. In order to control the ignition delay, this strategy adapts the amount of CNG injected into the pre-chamber with a linear controller or an extremum seeking algorithm depending on the air-to-fuel ratio of the main chamber.

The diesel engine converted to compressed natural gas (CNG) engine effect is lower in performance. Problem statement: The hypothesis is that the lower performance of CNG engine is caused by the effect of lower in engine cylinder pressure. Are the CNG engine is lower cylinder pressure than diesel engine? This research is conducted to investigate the cylinder pressure of CNG engine as a new engine compared to diesel engine as a baseline engine. Approach: The research approach in this study is by convert the diesel engine to multi point injection dedicated CNG engine. The engine conversion is by changed the diesel fuel to CNG fuel, changed the injection fuel system, changed the ignition system, modified piston to reduce the compression ratio and added throttle to in intake port. If the development is completed, the engine cylinder pressure is investigated. In this study, the cylinder pressure is investigated in 7 cases engine speed from 1000 to 4000 rpm with range in 500. Results: The research results are cylinder pressure and maximum pressure of CNG engine compared to diesel engine in 1000 to 4000 rpm engine speed. Conclusion/Recommendations: Effect of diesel engine converted to CNG engine is decrease the cylinder pressure. The further research is needed to find the higher performance of CNG engine.

Experimental study of hydrogen enriched compressed natural gas (HCNG) engine and application of support vector machine (SVM) on prediction of engine performance at specific condition

Natural gas is promising alternative fuel to meet strict engine emission regulations in many countries. Compressed natural gas (CNG) has long been used in stationary engines, but the application of CNG as a transport engines fuel has been conside rably advanced over the last decade by the development of lightweight high-pressure storage cy linders. Engine conversion technology is well established and suitable conversion equipment is re adily available. For spark ignition engines there a re two options, a bi-fuel conversion and use a dedicat ed to CNG engine. For compression ignition engines converted to run on natural gas, there are two main options discussed, there are dual-fuel engines and normal ignition can be initiated. Natur al gas engines can operate at lean burn and stoichiometric conditions with different combustion and emission characteristics. In this paper, the CNG engines research and development fueled using CNG are highlighted to keep the output power, torque and emissions of natural gas engines compara ble to their gasoline or diesel counterparts. The high activities for future CNG engines research and development to meet future CNG engines is recorded in the paper.

The natural gas as an alternative fuel has economical and environmental benefits. Bi-fuel engines powered by gasoline and compressed natural gas (CNG) are an intermediate and alternative step to dedicated CNG engines. The conversion to bi-fuel CNG engine could be a short-term solution to air pollution problem in many developing countries. In this paper a mathematical model of a bi-fuel four-stroke spark ignition (SI) engine is presented for comparative studies and analysis. It is based on the two-zone combustion model, and it has the ability to simulate turbulent combustion. The model is capable of predicting the cylinder temperature and pressure, heat transfer, brake work , brake thermal and volumetric efficiency, brake torque, brake specific fuel consumption (BSFC), brake mean effective pressure (BMEP), concentration of CO2, brake specific CO (BSCO) and brake specific NOx (BSNOx). The effect of engine speed, equivalence ratio and performance parameters using gasoline and CNG fuels are analysed. The model has been validated by experimental data using the results obtained from a bi-fuel engine. The results show the capability of the model in terms of engine performance optimization and minimization of the emissions. The engine used in this study is a typical example of a modified bi-fuel engine conversion, which could benefit the researchers in the field. gas as an automotive fuel may bring a reduction of environmental pollutants and reduce the economic costs of the transportation sector. As an intermediate step, and an alternative to dedicated CNG engines bi-fuel engines, powered by gasoline and compressed natural gas (CNG) provide many opportunities. With regard to the climatic situation of some countries, and considering the existence of broad networks of gas distribution natural gas can be a suitable alternative to conventional fuels. The growth of bi-fuel vehicle usage in some countries is dependent on local strategies for the gasification of vehicles, which can be categorized in different levels, for example: workshop conversion of vehicles (short-term approach), factory production of bi-fuel engines (mid-term approach) designing and producing base CNG engine (long-term approach) (2).Developing bi-fuel engines (gasoline and CNG) in the short and mid-term is a strategy for achieving the emission targets in some countries. Therefore, it is necessary to understand the engine performance in these cases. In support of the development of such engines and to aid analysis and improvement in this study, a four-stroke bi-fuel spark ignition (SI) engine model is developed specifically for simulation of turbulent combustion. Furthermore, a thermodynamics model of a bi-fuel SI engine in Matlab environment has been developed based on mathematical model that it described in section 2, and validated by experimental data. This model modified for CNG and gasoline and it has ability for evaluating of the engine performance and the emissions characteristic.

Hydrogen is an attractive fuel source not only because it is abundant and renewable but also because it produces almost zero regulated emissions. Internal combustion engines fueled by compressed natural gas (CNG) are operated throughout a variety of industries in a number of mobile and stationary applications. While CNG engines offer many advantages over conventional gasoline and diesel combustion engines, CNG engine performance can be substantially improved in the lean operating region. Lean operation has a number of benefits, the most notable of which is reduced emissions. However, the extremely low flame propagation velocities of CNG greatly restrict the lean operating limits of CNG engines. Hydrogen, however, has a high flame speed and a wide operating limit that extends into the lean region. The addition of hydrogen to a CNG engine makes it a viable and economical method to significantly extend the lean operating limit and thereby improve performance and reduce emissions. Drawbacks of hydrogen as a fuel source, however, include lower power density due to a lower heating value per unit volume as compared to CNG, and susceptibility to pre-ignition and engine knock due to wide flammability limits and low minimum ignition energy. Combining hydrogen with CNG, however, overcomes the drawbacks inherent in each fuel type. Objectives of the current study were to evaluate the feasibility of using blends of hydrogen and natural gas as a fuel for conventional natural gas engines. The experiment and data analysis included evaluation of engine performance, efficiency, and emissions along with detailed in-cylinder measurements of key physical parameters. This provided a detailed knowledge base of the impact of using hydrogen/natural gas blends. A four-stroke, 4.2 L, V-6 naturally aspirated natural gas engine coupled to an eddy current dynamometer was used to measure the impact of hydrogen/natural gas blends on performance, thermodynamic efficiency and exhaust gas emissions in a reciprocating four stroke cycle engine. The test matrix varied engine load and air-to-fuel ratio at throttle openings of 50% and 100% at equivalence ratios of 1.00 and 0.90 for hydrogen percentages of 10%, 20% and 30% by volume. In addition, tests were performed at 100% throttle opening, with an equivalence ratio of 0.98 and a hydrogen blend of 20% to further investigate CO emission variations. Data analysis indicated that the use of hydrogen/natural gas fuel blend penalizes the engine operation with a 1.5 to 2.0% decrease in torque, but provided up to a 36% reduction in CO, a 30% reduction in NOX, and a 5% increase in brake thermal efficiency. These results concur with previous results published in the open literature. Further reduction in emissions can be obtained by retarding the ignition timing.

Natural gas is considered to be a promising alternative fuel for passenger cars, truck transportation and stationary engines providing positive effects both on the environment and energy security. However, since the composition of natural gas fuel varies with location, climate and other factors, it is anticipated that such changes in fuel properties will affect emission characteristics and performance of CNG (Compressed Natural Gas) engines. The purpose of the present study is to investigate the effects of the difference in gas composition on the engine performance and emission characteristics, The results show that THC (Total Hydrocarbon) decreases with increasing WI (Wobbe Index) and MCP (Maximum Combustion Potential). On the other hand, it is observed that NOx slightly increases as WI and MCP increase. The TLHV (Total Lower Heating Value of Intake) is proposed in this study as a potential index for compatibility of gas fuels in a CNG engine. There is a variation in power up to 20% depending on the composition of gas when the A/F ratio and spark timing are fixed for a specific gas fuel.

Compressed natural gas (CNG) has been used as a fuel for internal combustion engines for decades. Developing single fuel CNG engine which has better economy and can meet more strict emission regulations becomes more and more important. The objective of the paper is to present the development of a new CNG engine electronic control system and some calibration tests results to the engine, including the engine description, the description of the engine control system, the design of the Electronic Control Unit (ECU) hardware, the electronic control strategy of the engine based on the structure of the fuel system for the EQD180N-30 engine and the program for the ECU with C language corresponding to the ECU's hardware. The test results show that the engine can operate reliably with the new designed fuel system, engine performance like power, torque and fuel consumption can meet the design requirements; so the electronic system has been successfully developed.

Compressed natural gas is one of the alternative fuels for internal combustion engines as they produce less smoke and greenhouse gas emission. Understanding the combustion characteristics of compressed natural gas engines help experts to come up with better combustion chamber designs for high performance and low emission engines. In this study, three different designs of piston bowl geometry in a retrofitted compressed natural gas engine were investigated in relation to engine performance and its combustion characteristics. Three types of piston-tops including two concentric bowls and one eccentric bowl operated with two different values of compression ratio (11.5:1 and 12.5:1) were the subject of the current research. Based on the results from the experiment and simulation performed in this investigation, while differences in bowl-in-piston design did not have any significant effect on engine performance and combustion characteristics of port injection compressed natural gas engines, the authors observed a significant impact of advance ignition angle and spark plug location relative to bowl’s centerline having on the combustion process and engine performance characteristics. As a result, the application of concentric bowl-in-piston and compression ratio of 11.5:1 was found to yield the lowest brake specific fuel consumption and the highest brake power. The particular outcome presents a potential strategy for the combination of piston-top shape and compression ratio in compressed natural gas engine application to attain high combustion efficiency.

Experimental Study on CNG Engine with Different Ventury Configuration

The world is having catastrophe of environmental pollution and fossil fuel depletion. Adaptation of alternative fuels is a healthy solution in reducing exhaust emissions in the automobile sector. Compressed Natural Gas (CNG) as a fleet fuel has played a vital role in the HCV sector. Many developmental and optimization work has been taken place for the CNG engines in the recent times. Due to the recent upsurge in diesel prices, the HCV sector is moving towards the CNG fuel vehicle. The HCV sector requires a heavy performance engine for its day-to-day application. In this research paper a baseline six-cylinder, naturally aspirated CNG engine used for bus application is selected to upgrade its power and torque performance. Based on the baseline CNG engine data, an appropriate turbocharger for the engine is selected with the help of M/s Garrett turbocharger manual. A 2-D simulation of the turbine is also carried out to understand the pressure and temperature distribution profile inside the turbine. The experimental results showing the increase in power, torque, volumetric efficiency, BMEP and thermal efficiency is illustrated in the research work below.