Browse Topic: Fuel lines
When the flow of fluid within a high-pressure line is abruptly halted, pressure pulsations are generated. This phenomenon is known as the water hammer effect. This may lead to significant stress and, in the worst-case scenario, results in various types of failures within the highly pressurized system. Similar issues are observed in diesel high pressure fuel line where pressure is well above 1600 bar. Due to multiple injections on-off events, pressure pulsation gets created inside high pressure fuel lines (HPFL) which leads to problems such as high strain on high pressure fuel lines, mechanical damage, uneven fuel injected quantity, vibration beyond specification limits for rail pressure sensors or in worst case extreme noise. This is due to high pressure pulsation which occurs when fluid/fuel natural frequency resonates with structural HPFL natural frequency. In this work, A comparative FEA analysis is conducted to evaluate strain in two distinct high-pressure fuel lines, with pressure pulsation serving as the forcing function. Pressure pulsation inside HPFL is obtained from hoop strain gauges. As high-pressure fuel lines are the thick-walled cylinders, pressure inside HPFL can be calculated using Lame’s equation of hoop stress in thick-walled cylinder. This obtained pressure pulsation signal is calibrated to account for variation due to autofrettage, temperature compensation, etc. The Fast Fourier Transform (FFT) of obtained pressure pulsation signal is used as a forcing function for harmonic analysis and comparative assessment is done between two distinct lines. Also, the intensity and frequency of pressure pulsations can vary depending on engine speed, load conditions, and design of the fuel system. A sensitivity study is performed to check the impact of speed and load on pressure pulsation in HPFL.
Most of current jet aircraft circulate fuel on the airframe to match heat loads with available heat sink. The demands for thermal management in wide range of air vehicle systems are growing rapidly along with the increased mission power, vehicle survivability, flight speeds, and so on. With improved aircraft performance and growth of heat load created by Aircraft Mounted Accessory Drive (AMAD) system and hydraulic system, effectively removing the large amount of heat load on the aircraft is gaining crucial importance. Fuel is becoming heat transfer fluid of choice for aircraft thermal management since it offers improved heat transfer characteristics and offers fewer system penalties than air. In the scope of this paper, an AMESim model is built which includes airframe fuel and hydraulic systems with AMAD gearbox of a jet trainer aircraft. The integrated model will be evaluated for thermal performance. JP-8 fuel is recirculated on the airframe to maintain cooling the oil for AMAD gearbox and the hydraulic fluid for the hydraulic systems. A Fuel/Oil Heat Exchanger (FOHE) is integrated on the airframe main fuel line with a thermally actuated valve located at the fuel outlet port, which prevents fuel temperature from exceeding limitations at the airframe/engine fuel interface. The valve opens at a specified fuel temperature allowing excessive fuel to return to main fuel tank that increase fuel flow through the heat exchanger. AMAD and hydraulic systems also have their own thermal by-pass valves to adjust fluid quantity to be sent to the heat exchanger for cooling.
For better fuel economy and reduced emissions; fuel system plays a very important role. There are some major challenges related to development of suitable fuel system due to high static (~2000 bar) and fluctuating pressures in high pressure (HP) fuel lines. This enforces to design leak proof joints as they directly affect engine operation and can cause customer inconvenience. It is also critical from safety standpoint. Sealing capability of a joint is generally evaluated by sealing pressure, length of the sealing width and retaining capability of joint preload over time. Theoretically, it is known that preload loss at a joint is a combination of several factors such as; thread pitch, nut stiffness and friction at threads. In our current work the cause of leakage in HP fuel line joints is explored. Using fish bone diagram for RCA (Root Cause Analysis), probable causes are narrowed down and design parameters responsible for preload loss are identified. A parametric study has been performed for different designs to evaluate their preload retaining capability. Additionally; end form of fuel joints, collar and frictional coefficient are studied to understand their impact on sealing capability as the part of this work. Sealing capability of two different engine platforms are evaluated through Finite Element Analysis (FEA) simulation and analytical methods. The results are validated through testing. The key findings of the current work can be useful in FEA and analytical modelling of HP fuel lines to evaluate joint sealing capability and will be helpful in designing better fuel line system in future.
During operation, it is advisable to periodically monitor the actual fuel consumption of the vehicle. Fuel consumption can be used to assess the driving conditions and technical condition of the vehicle, which affects the intensity of environmental pollution. The engine control system calculates fuel delivery based on driving conditions and vehicle load based on information from sensors. When diagnosing on fuel economy, it is convenient to directly measure the consumption in the fuel line of the delivery system. The advantages and disadvantages of the main types of different flow sensors were analyzed. It is proposed to measure the amount of fuel per unit of time with a piston volumetric flow meter. The design of a software and hardware system for measuring fuel consumption has been developed, which consists of control systems for the actuators of the flow meter and a system for recording and processing information in a microcontroller. Organized data transfer from the flow meter to an external diagnostic module via the CAN-bus. A protocol was developed for transmitting diagnostic information to a computer and an interface for interacting with the user. The possibility of using a flow meter for measuring differential flow connected in forward and reverse directions is considered. An algorithm has been developed for a program that is embedded in a microprocessor. A procedure was developed for calibrating the flow meter, which allowed an estimate of the total uncertainty. The values of the absolute and relative errors were obtained over the entire range of the measured indicator. The coefficients of linear correction of the working volume of the fuel flow meter are obtained, which are used in the control program for the flow meter. Computer software has been developed that can receive data from the flow meter via USB, displays general information on fuel consumption on the computer screen in graphic and text form. Experimental studies have been carried out to determine the fuel consumption of a passenger car on the road using this flow meter. The use of a fuel flow meter allows you to control the efficiency of fuel supply, timely detect hidden vehicle malfunctions, and assess the quality of operating conditions. Conclusions and recommendations are developed, the main ways of further research are indicated.
To overcome the limitations such as lower combustion efficiency (CE) and higher cyclic variability in methanol/diesel (M/D) reactivity controlled compression ignition (RCCI) combustion, a fuel having higher reactivity than diesel (i.e., polyoxymethylene dimethyl ethers, PODE) was used in our previous study. Methanol/PODE RCCI combustion resulted in improved CE and reduction in soot and unburned emissions compared to M/D RCCI combustion. However, it was noticed that the use of neat PODE as high-reactivity fuel had damaged the fuel line materials frequently due to its higher oxygen content and lower viscosity. In addition, Methanol/PODE RCCI has also resulted in higher NO emissions compared to M/D RCCI combustion. Hence to sort this out, an attempt is made in this study to investigate the effect of PODE-diesel blend on dual-fuel RCCI combustion in order to propose a suitable blend proportion which can tackle the fuel line material damage, increased NO emissions, CE, and cyclic variability. In the present investigation three PODE-diesel blends, namely, PODE10, PODE30, and PODE50, have been prepared and tested at 21 kW and 28 kW fuel energy input (FEI) conditions. Since the fuel composition has changed from PODE to PODE-diesel blends, to gain similar benefits, experiments have been performed at both early and late injection strategies at a constant combustion phasing (CA50) of about 10°CA aTDC and 20% EGR. The experimental results indicated that a higher PODE blend ratio reduced the cyclic variability and increased CE. Methanol/PODE50 RCCI operation indicated 2% improvement in CE, 2.9% increase in brake thermal efficiency (BTE), and 3.1% reduction in COVIMEP compared to M/D RCCI combustion. However, still the NO emission is marginally higher compared to M/D RCCI combustion and significantly lower than methanol/PODE RCCI combustion.
Regulations regarding evaporative emissions have set more and more stringent limits over the last years. To fulfill these specifications, original equipment manufacturers (OEMs) now tend to break down the sum value of evaporative emissions for the whole car onto single parts or components. Especially small, fuel-containing components (fuel lines, pressure sensors, injection systems, etc.) are challenging. Very low emission rates (<1 mg/24 h) must be measured precisely, and also the stability of these values must be verified due to fuel equilibration effects. Standard SHED (sealed housing evaporative determination) systems or test chambers for measuring volatile organic compound (VOC) emissions are often too big and have too high background levels to achieve reliable results. In addition they are quite expensive which affects the costs per measurement. Our aim was to develop a low-cost Micro-SHED system which fulfills the abovementioned requirements. Commercial gas-tight aluminum boxes with a volume of about 73 L were modified using a Tedlar bag and a fan. Four of those boxes can be put in a standard 1 m3 VOC emission test chamber for temperature control. Measurements are performed by one flame ionization detector (FID), which samples the boxes successively. Parameters such as repeatability, recovery, and retention were determined. Results show that the performance regarding these parameters is within the requirement range given by the California Air Resources Board (CARB) Standards and Test Procedures with few exceptions. Background emission rates are less than 0.1 mg/24 h over the CARB Diurnal Soak temperature profile. The parallel measurement of four parts using only one 1 m3 SHED reduces the costs per part considerably. The new Micro-SHED system allows testing more parts in the same time or measuring up to four identical samples in parallel to get more reliable results. This setup was used for the determination of emission rates of fuel hoses, pressure sensors, and injector seals.
Specific federal aviation regulations (Titled 14 of the United States Code of Federal Regulations, or 14 CFR) define oxygen system requirements for an in-flight decompression incident. This AIR addresses the operational oxygen system requirements for a decompression incident that may occur at any point during a long-range flight, with an emphasis for a decompression at the equal time point (ETP). This AIR identifies fuel and oxygen management contingencies, and presents possible solutions for the efficient, safe, and optimum fuel/oxygen flight continuation. Oxygen management is a concern to all aircraft, such as single engine types that fly above 10 000 feet and use supplemental oxygen. This document provides a method which can help guide users in developing an oxygen solution for their aircraft.
This SAE Recommended Practice provides guidance for the construction, operation, and maintenance of CNG powered medium and heavy-duty trucks. The intent of this document is to cover TRUCKS (6350 kg (14 001 gvw pounds) and above) and specifically excludes passenger vehicles such as: buses, recreational vehicles, motor homes and/or passenger vehicles which may incorporate a truck chassis in their construction.
In respect to the present large refrigerator trucks, sub-engine type is the main product, but the basic structure does not change greatly since the introduction for around 50 years. A sub-engine type uses an industrial engine to drive the compressor, and the environmental correspondence such as the fuel consumption, the emission is late remarkably. In addition, most of trucks carry the truck equipment including the refrigerator which consumes fuel about 20% of whole vehicle. Focusing on this point, the following are the reports about the system development plan for fuel consumption reduction of the large size refrigerator truck. New concept is to utilize electrical power from HV system to power the electric-driven refrigerator. We have developed a fully electric-driven refrigerator system, which uses regenerated energy that is dedicated for our refrigerator system. It is the world’s first new concept to use the all electricity that regenerated by HV system for the drive of our electric refrigerator, not only for a run assist. Not limited to the high quality and stability refrigerator performance, it also realizes the reduction of the fuel and noise during the freezing operation. Fuel consumption reduced due to light weight drive system by replacing the heavy sub-engine to an electric compressor and also elimination of additional fuel line for sub-engine. Also, the maintenance expense can decrease because of the simple drive system and piping layout. By the all-in-one unit structure which is integrated an electric compressor close to the evaporator and condenser, the refrigerant piping is largely shortened and the efficiency and the reliability of the refrigerator are improved. We have proven that the system is able to save fuel consumption up to 64% by applying new control system which considers cooperation with the vehicle hybrid control system.
Electric and alternative fueled vehicles present different hazards for first and second responders than conventional gasoline internal combustion engines. Hydrogen vehicles (H2V) including Fuel Cell Vehicles (FCVs) involved in incidents may present unique hazards associated with the fuel storage and high voltage systems. The electrical hazards associated with the high voltage systems of hybrid-electric vehicles and FCVs are already addressed in the parent document, SAE J2990. This Recommended Practice therefore addresses electric issues by reference to SAE J2990 and supplements SAE J2990 to address the potential consequences associated with hydrogen vehicle incidents and suggest common procedures to help protect emergency responders, tow and/or recovery, storage, repair, and salvage personnel after an incident has occurred. Industry design standards and tools were studied and where appropriate, suggested for responsible organizations to implement.
Hoffer Flow Controls Elizabeth City, NC 252-331-1997
The Fuel Supply Module, FSM, is responsible to deliver fuel to engine in all application range in correct system pressure. It is usually installed inside the fuel tank. The pressure regulator is a component used in vehicles to regulate the engine fuel line pressure. This component is usually placed inside the tank, in the FSM. In some cases it is assembled at the fuel supply module flange due to layout restrictions. One application was released for 380kPa, without any problems. Once the system pressure was increased to 420kPa, it was observed noise problems in vehicle at high temperatures. It was investigated the root cause for the abnormal noise and observed the pressure regulator natural frequency matching with the flange housing natural frequency at specific conditions. The objective of this paper is to describe a methodology to identify and solve a noise problem using the design elements influence based on its behavior.
Global automobile market is very sensitive to vehicle fuel economy. Gross vehicle weight has substantial effects on FE. Hence, for designers it becomes utmost important to work on the weight reduction ideas up to single component level. Fuel delivery pipe (Fuel Rail) is one such component where there is a big potential. Fuel rail is an integral part of the vehicle fuel system and is mounted on the engine. Primarily it serves as a channel of fuel supply from fuel tank through fuel lines to the multiple fuel injectors, which further sprays the fuel into intake ports at high pressure. Due to opening and closing of injectors, pulsations are generated in fuel lines, so fuel rail also acts as a surge tank as well as a pulsation damper. All these factors make the design of a fuel rail very critical and unique for a particular engine. Materials like aluminum, plastic and sheet metal are generally used for fuel rail manufacturing. In this technical paper, design considerations for plastic fuel rail are explained. This paper includes: 1 Design considerations during raw material selection 2 Factors of a fuel rail design 3 Brief explanation of other important design parameters/considerations 4 Benefits of new design
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