High-Compression-Ratio; Atkinson-Cycle Engine Using Low-Pressure Direct Injection and Pneumatic-Electronic Valve Actuation Enabled by Ionization Current and Foward-Backward Mass Air Flow Sensor Feedback

This report describes the work completed over a two and one half year effort sponsored by the US Department of Energy. The goal was to demonstrate the technology needed to produce a highly efficient engine enabled by several technologies which were to be developed in the course of the work. The technologies included: (1) A low-pressure direct injection system; (2) A mass air flow sensor which would measure the net airflow into the engine on a per cycle basis; (3) A feedback control system enabled by measuring ionization current signals from the spark plug gap; and (4) An infinitely variable cam actuation system based on a pneumatic-hydraulic valve actuation These developments were supplemented by the use of advanced large eddy simulations as well as evaluations of fuel air mixing using the KIVA and WAVE models. The simulations were accompanied by experimental verification when possible. In this effort a solid base has been established for continued development of the advanced engine concepts originally proposed. Due to problems with the valve actuation system a complete demonstration of the engine concept originally proposed was not possible. Some of the highlights that were accomplished during this effort are: (1) A forward-backward mass air flow sensor has been developed and a patent application for the device has been submitted. We are optimistic that this technology will have a particular application in variable valve timing direct injection systems for IC engines. (2) The biggest effort on this project has involved the development of the pneumatic-hydraulic valve actuation system. This system was originally purchased from Cargine, a Swedish supplier and is in the development stage. To date we have not been able to use the actuators to control the exhaust valves, although the actuators have been successfully employed to control the intake valves. The reason for this is the additional complication associated with variable back pressure on the exhaust valves when they are opened. As a result of this effort, we have devised a new design and have filed for a patent on a method of control which is believed to overcome this problem. The engine we have been working with originally had a single camshaft which controlled both the intake and exhaust valves. Single cycle lift and timing control was demonstrated with this system. (3) Large eddy simulations and KIVA based simulations were used in conjunction with flow visualizations in an optical engine to study fuel air mixing. During this effort we have devised a metric for quantifying fuel distribution and it is described in several of our papers. (4) A control system has been developed to enable us to test the benefits of the various technologies. This system used is based on Opal-RT hardware and is being used in a current DOE sponsored program

A Hydraulic Actuated Thermal Management System For Large Displacement Engine Cooling Systems

The performance of automotive cooling systems can be improved by replacing the traditional mechanically driven radiator fan and water pump assemblies with computer controlled components. The introduction of electric servo-motors to drive the cooling components can improve temperature tracking, which should increase fuel efficiency and decrease tailpipe emissions. However, the power requirement for these electric motors increases with greater cooling demands if the radiator surface area remains constrained. For heavy-duty applications, where engines are subjected to significant cooling loads, electric motors may become impractical due to their increased size and power requirements; in these situations, hydraulic-based components are advantageous due to their high power density. The off-road equipment industry currently uses hydraulic radiator fan drives for cooling applications, while the coolant pump remains mechanically driven. Therefore, an opportunity exists to integrate the radiator fan and coolant pump into hydraulic circuits to actively meet cooling demands. In this research project, an automotive thermal management system, which features a computer controlled hydraulically actuated fan and coolant pump, was investigated. A series of analytical mathematical models were derived for the hydraulic and thermal system components. An experimental test bench was constructed, which implements a hydraulic based radiator fan and water pump, as well as electric immersion heaters to simulate the heat of engine combustion. The test bench was used to validate the mathematical models and study the proposed cooling system\u27s ability to regulate engine temperature. Classical control methods have been applied to control the coolant temperatures by integrating the temperature, shaft speed, and hydraulic pressure feedback information. Further, the performance of two types of hydraulic flow control valves has been studied to offer design engineers insight into actuator behavior. The dynamic hydraulic and thermal system models displayed good correlation with data obtained from the experimental test bench (steady-state errors below 1.6%). Additionally, the experimental system demonstrated excellent temperature tracking results (maximum 0.20¡K steady-state set point deviation) when using servo-solenoid valves to control the speed of the hydraulic motor driven radiator fan and water pump. However, when using the more cost effective solenoid poppet valves, the system exhibited limited temperature tracking abilities (maximum 2.48¡K steady-state set point deviation). Still, each valve displayed minimal power usage (by the pump and fan motors) with the servo valves consuming on average 58-160 Watts and the poppet valves consuming on average 66-128 Watts. The hydraulic actuated thermal management system has the ability to effectively regulate engine temperatures while offering the potential for power minimization to increase fuel efficiency and reduce emissions. Despite their higher cost, servo-solenoid hydraulic control valves may be a good choice for controlling actuator speeds and regulating engine temperatures. Solenoid poppet valves offer a lower cost alternative to the servo-solenoid valves, but temperature tracking performance may be sacrificed. To study the power saving potential of hydraulic based thermal management systems, future experiments should include on-vehicle comparisons of the traditional and hydraulic based thermal management approaches

Fully variable valve actuation in large bore diesel engines

Diesel engine combustion process optimization has become increasingly important as environmental and economic issues are setting more strict conditions on engines. Best efficiency and lowest emission are not reached at the same time, and compromise between these is required. The more flexible the control of the combustion is, the more effective operation of the diesel engine is gained with required emission levels. Variable gas exchange valve actuation is one effective method of adjusting the combustion process, and it has already been successfully used for years in passenger cars. Variable actuation can be implemented either by a mechanical, electric or electro-hydraulic device. All constructions have pros and cons, and it depends on the application which is best suited for the case in question. The large bore diesel is a very challenging application where masses and forces are high, and required movement distances long. An electro-hydraulic actuation gives a benefit where almost full flexibility of the valve events is reached and full potential of the variable valve actuation can be used. Electro-hydraulic valve actuation is investigated in this study via simulations and measurements. The used hydraulic circuit and actuator construction has a strong effect on the performance of the valve actuation system. A 3-way controlled actuator gives the lowest energy consumption, and the control valve characteristic has a major role in overall performance. Right dimensioning of the gas exchange valve return spring is important. An energy consumption decrease of up to 20% could be achieved if the actuator was optimized. Because the actuation system is not mechanically linked on the engine piston position and the dynamics of the valve actuation system are challenging, a reliable and accurate control system is needed. Pure P-control is not good enough, and a state controller is too complex to use when environment variables change. An iterative learning feature can adapt automatically in different working points and it can also execute good tracking error through the whole gas exchange valve lift

Nonlinear System Modeling, Optimal Cam Design, and Advanced System Control for an Electromechanical Engine Valve Drive

A cam-based shear force-actuated electromechanical valve drive system offering variable valve timing in internal combustion engines was previously proposed and demonstrated. To transform this concept into a competitive commercial product, several major challenges need to addressed, including the reduction of power consumption, transition time, and size. As shown in this paper, by using nonlinear system modeling, optimizing cam design, and exploring different control strategies, the power consumption has been reduced from 140 to 49 W (65%), the transition time has been decreased from 3.3 to 2.7 ms (18%), and the actuator torque requirement has been cut from 1.33 to 0.30 N·m (77%).Sheila and Emanuel Landsman Foundatio

Hydraulic Actuated Automotive Cooling Systems - Nonlinear Control and Test

The replacement of traditional automotive mechanical cooling system components with computer controlled servo-motor driven actuators can improve temperature tracking and reduce parasitic losses. The integration of hydraulic actuators in the engine cooling circuit offers greater power density in a smaller package space when compared with electric actuators. In this paper, a comprehensive nonlinear backstepping robust control technique is developed to regulate the engine coolant temperature by controlling a hydraulic coolant pump and radiator fan. An experimental test bench has been assembled to investigate the hydraulic automotive thermal system performance. Representative numerical and experimental results are presented and discussed. Overall, the proposed controller was successful in tracking prescribed engine temperature profiles while harmoniously regulating the power consumption of the coolant pump and radiator fan

A review of electro-hydraulic servovalve research and development

This paper provides a review of the state of the art of electro-hydraulic servovalves, which are widely used valves in industrial applications and aerospace, being key components for closed loop electrohydraulic motion control systems. The paper discusses their operating principles and the analytical models used to study these valves. Commercially available units are also analysed in detail, reporting the performance levels achieved by current servovalves in addition to discussing their advantages and drawbacks. Adetailed analysis of research that investigates these valves via computational fluid dynamic analysis is also provided. Research studies on novel control systems and novel configurations based on the use of smart materials, which aim to improve performance or reduce cost, are also analysed in detail.</p

A review of electro-hydraulic servovalve research and development

This paper provides a review of the state of the art of electro-hydraulic servovalves, which are widely used valves in industrial applications and aerospace, being key components for closed loop electrohydraulic motion control systems. The paper discusses their operating principles and the analytical models used to study these valves. Commercially available units are also analysed in detail, reporting the performance levels achieved by current servovalves in addition to discussing their advantages and drawbacks. Adetailed analysis of research that investigates these valves via computational fluid dynamic analysis is also provided. Research studies on novel control systems and novel configurations based on the use of smart materials, which aim to improve performance or reduce cost, are also analysed in detail.</p

A dual lane piezoelectric ring bender actuated nozzle-flapper servo valve for aero engine fuel metering

Amongst many other high performance flow control applications, servo valves are used to control aero engines by metering the fuel delivered from the fuel pump. Conventionally, a fuel metering servo valve has a pilot stage with an electromagnetic torque motor moving a flapper which differentially restricts a pair of nozzles to create a hydraulic signal (i.e. a pressure difference). These valve pilot stages use mature, optimised technology such that to achieve improvements requires a novel approach. Torque motors in particular present reliability and manufacturing difficulties, and news solutions should ultimately allow a reduction in manual assembly and set-up, improve repeatability, and eliminate failures associated with fine wire devices. In this paper, a pilot stage actuated by piezoelectric ring benders is proposed, designed, built and tested, and test results are compared with a model used to predict pressure-flow characteristics. A particular challenge is the need to include redundancy, and thus a pair of ring benders is used, allowing isolation between duplicated electrical control channels. Another challenge is the mounting of the ring bender, which has to flex to allow the outer edge of the ring bender to deform, yet be stiff enough to adequately react against generated forces. O-ring mounts made from three different elastomer materials are compared in this study. In aerospace, an added complication is the large range of fuel temperature; F70 fluorosilicone O-rings have been chosen with this in mind, and successfully demonstrated in the range -50 C to +180 C. With one active and one inactive ring bender to simulate a failure condition, the new dual lane pilot stage achieves +/-50 μm displacement under test, giving control port flows up to +/-0.6 l min -1, and a control port pressure variation of 40 bar using a 100 bar supply pressure difference (supply minus return pressure). This research establishes that a piezoelectric aero engine fuel valve is feasible, and in particular, that piezoelectric ring bender actuators with elastomeric mountings are highly suited to this application. </p

Volume 3 – Conference

We are pleased to present the conference proceedings for the 12th edition of the International Fluid Power Conference (IFK). The IFK is one of the world’s most significant scientific conferences on fluid power control technology and systems. It offers a common platform for the presentation and discussion of trends and innovations to manufacturers, users and scientists. The Chair of Fluid-Mechatronic Systems at the TU Dresden is organizing and hosting the IFK for the sixth time. Supporting hosts are the Fluid Power Association of the German Engineering Federation (VDMA), Dresdner Verein zur Förderung der Fluidtechnik e. V. (DVF) and GWT-TUD GmbH. The organization and the conference location alternates every two years between the Chair of Fluid-Mechatronic Systems in Dresden and the Institute for Fluid Power Drives and Systems in Aachen. The symposium on the first day is dedicated to presentations focused on methodology and fundamental research. The two following conference days offer a wide variety of application and technology orientated papers about the latest state of the art in fluid power. It is this combination that makes the IFK a unique and excellent forum for the exchange of academic research and industrial application experience. A simultaneously ongoing exhibition offers the possibility to get product information and to have individual talks with manufacturers. The theme of the 12th IFK is “Fluid Power – Future Technology”, covering topics that enable the development of 5G-ready, cost-efficient and demand-driven structures, as well as individual decentralized drives. Another topic is the real-time data exchange that allows the application of numerous predictive maintenance strategies, which will significantly increase the availability of fluid power systems and their elements and ensure their improved lifetime performance. We create an atmosphere for casual exchange by offering a vast frame and cultural program. This includes a get-together, a conference banquet, laboratory festivities and some physical activities such as jogging in Dresden’s old town.:Group 8: Pneumatics Group 9 | 11: Mobile applications Group 10: Special domains Group 12: Novel system architectures Group 13 | 15: Actuators & sensors Group 14: Safety & reliabilit