Engine Control Applications Research Articles

Materials Challenges in Automotive Embedded Non-Volatile Memories

AbstractSilicon-based nonvolatile memory modules are widely used in microcontrollers, where they are embedded into a monolithic system on a chip (SoC) which also includes high speed logic transistors, cache SRAM, and peripheral circuits for communicating with the external world. The physical principle most widely exploited for nonvolatile code and data storage is charge storage in floating gates. Recently, charge storage in nitride traps and nanocrystals also has been explored.The most demanding use profiles with respect to temperatures, data retention times, and low failure rates are encountered in automotive engine control applications, where junction temperatures up to 150°C are common, for 1000's of hours. Starting with the 130nm technology node, embedded Flash technology has been integrated with copper interconnects, and at the 90nm node, low dielectric constant interlevel dielectrics are also employed to increase circuit performance. To achieve automotive reliability, the materials surrounding the silicon floating gate, nanocrystal, or nitride charge storage area must be evaluated for parasitic charge storage, write/erase stress-induced leakage current, and other parameters important for reliability. Any movement of parasitic charge, potentially over a long period of time, can reduce the sensing window of the Flash EEPROM bitcell.

Sinusoidal Behavior of a Dipole Magnetization for Position Sensing Applications

Magnetic position sensing is used in many applications, especially in environments where the sensor is subjected to vibrations, temperature variations, or high humidity. The Hall effect position sensors, due to their simplicity and versatility, are elegant solutions to many application requirements, although the disadvantage are a maximum operating temperature of about 175°C, airgap operation limited to no greater than about 2.5mm and sensitivity to external pressure acting on the sensor package [1]. The need for sensors is growing, for example, in automotive applications, where, in engine control applications, the number of sensors used will increase from about ten in 1995, to more than thirty in 2010 [2]. Magnetic position sensing is based on the measurement of the magnetization pattern of a di-pole, or multi-pole, magnetic ring using a Hall sensor, which shows the variation of the magnetic field density along the circumference of the ring. The ideal magnetic behavior of the permanent magnet ring has a sinusoidal hall-sensor output, which makes it suitable for sensing applications. However, practical measurements show that the sinusoidal behavior sometimes occurs with errors. This paper describes the investigation of these errors by means of mismatch in the magnetization pattern of the di-pole permanent magnet (PM)-ring. The PM-ring yields that the developed magnetic flux is purely sinusoidal, where the geometrical dimensions of the PM-ring influence the magnitude Hall-sensor output voltage level. A deviation in the sinusoidal behavior is influenced by a non-ideal PM-ring by means of varying magnetic flux density magnitude and orientation.

Special issue on control applications in automotive engineering

Special issue on control applications in automotive engineering

Special issue on control applications in automotive engineering

Special issue on control applications in automotive engineering

Special issue on control applications in automotive engineering

Special issue on control applications in automotive engineering

Designing Robust Repetitive Controllers

A method for designing repetitive feedback controllers using nonparametric frequency response plant models is developed. In comparison to the zero-phase-error (ZPE) controller (ASME J. Dyn. Syst. Meas. Control, 111, pp. 353–358), this method has the added benefit of providing improved transient performance when the plant inverse is unstable. In this controller design process, a connection is made between model uncertainty and the desired frequency response of the so-called q filter. Also, it will be shown that an optimal equiripple filter is useful when designing high-order q filters. The entire process was experimentally verified on an engine control application. A repetitive controller was used to determine the dynamic fueling requirements of a fuel injected, spark-ignition engine subjected to periodic changes in the throttle position. This fueling information is necessary when designing feedforward fueling algorithms.

Nonlinear Predictive Control of Transients in Automotive Variable Cam Timing Engine Using Nonlinear Parametric Approximation

The paper considers design of a predictive Linear Time Varying model-based controller with nonlinear feedforward for regulation of transient processes caused by setpoint step changes in a nonlinear plant. An optimal feedforward control sequence is computed based on an empirical Finite Impulse Response model of the process. Though the control techniques developed in this paper are meant to have more general industrial applicability, a specific automotive engine control application—control of Variable Cam Timing automotive engine—is pursued. An advantage of the proposed controller design in this problem is that no first principle models are required. Instead, nonlinear parametric approximations of a neural network type are being used to describe and identify static nonlinear mappings encountered in the problem. A number of simplifying assumptions and approximations are made to make practical implementation of the proposed scheme possible. Validity of the designed controller is verified by simulation. The proposed “model-free” design can potentially increase flexibility and save labor in development and deployment of such controllers for industrial systems.

Recursive spline interpolation method for real time engine control applications

In this paper, new computationally efficient algorithms for spline interpolation method are explained. Theoretical comparative analysis of the spline interpolation method with combined high-gain observer and spline interpolation method is presented. New spline interpolation algorithms are implemented for estimation of the engine angular acceleration from the crankshaft angle measurements.

Kinetics of Oxygen Exchange in Sr(Ti0.65Fe0.35)O3

ABSTRACTCurrent limiting electrochemical pumping cells (amperometric sensors) based on zirconia are commonly used for engine control applications. Fast resistive-type sensors adapted from semiconducting metal oxides are a promising alternative for future exhaust gas monitoring systems. Therefore among the interesting characteristics of the materials system Sr(Ti0.65Fe0.35)O3, including high sensitivity and temperature independence at high oxygen partial pressures (pO2 > 10-4 bar), a short response time (t90 = 30 ms) is obviously the most salient.The latter is determined by the kinetics of the oxygen surface transfer and subsequent diffusion of oxygen vacancies V‥O. For thin samples and low temperatures the surface transfer is dominant, since bulk diffusion usually occurs very fast. The presented model is based on the frequency-domain analysis of amplitude and phase shift of the response signal obtained from a pO2 modulation in a fast kinetic measurement setup. This method allows both the measurement of response times in the sub-millisecond range as well as the distinction of the behaviour either controlled by volume diffusion or by surface transfer reaction in Sr(Ti0.65Fe0.35)O3 ceramics.

Principles of solid state oxygen sensors for lean combustion gas control

This paper gives an overview about oxygen sensors for automotive applications to control the air–fuel ratio in order to reduce emissions and fuel consumption. The three-way catalyst system (TWC) using the potentiometric sensors based on zirconia represents the most effective system for the emission control at this time. New control strategies with linear lambda control at λ=1, for direct injection engines and other lean burn engines operating with excess air ( λ>1) need alternative sensor concepts. Hence, current limiting electrochemical pumping cells (amperometric sensors) based on zirconia have been developed for engine control applications. As a future option we present also new research works in resistive type oxygen sensors based on semiconducting metal oxides.

Musical instruments as tools for teaching acoustics to engineering students

Kettering University offers an undergraduate minor in acoustics anchored by two lecture courses and a laboratory project course taught by physics faculty. While many of the students who take these courses are more interested in the engineering and noise control applications of acoustics, most are familiar with musical instruments and quite a few play an instrument. We have found that in several instances a discussion of the acoustics of a musical instrument can be very effective at facilitating an understanding of the fundamental concepts behind the engineering applications of acoustics our students encounter at their co-op work experiences. Examples include: the physics of guitar pickups, hose trumpets, ocarinas, low-frequency models of acoustic guitars, sound radiation from drum membrane modes, radiation from a tuning fork, musical scales and intervals, and audio demonstrations of pitch and timbre. This talk will discuss and demonstrate how several such examples are used as classroom demonstrations, homework projects, and laboratory experiments.

Evaluation of Capture Efficiencies of Large Push-Pull Ventilation Systems with Both Visual and Tracer Techniques

Twenty large open-surface metal finishing process tanks equipped with push-pull ventilation systems were tested to determine contaminant capture efficiencies. Adequate control of tank gas and vapor emissions is necessary for both employee exposure and fugitive air pollution considerations. In addition to videotaped smoke testing, novel tracer gas methods were employed to ascertain capture efficiencies before and after the application of engineering controls. Real-time infrared (IR) detection of sulfur hexafluoride (SF6) tracer gas permitted convenient adjustment of push- and pull-air flow for optimum capture efficiency. Capture efficiencies of about 93% or better were attainable for the 2.4by 4.9 m (8 by 16 ft) processing tanks. The careful control of cross-drafts was shown to be the most significant factor in achieving successful contaminant capture at tank liquid surfaces. Consequently, additional engineering controls were implemented to improve the effectiveness of the ventilation system, such as reduc...

Evaluation of Capture Efficiencies of Large Push-Pull Ventilation Systems with Both Visual and Tracer Techniques

Twenty large open-surface metal finishing process tanks equipped with push-pull ventilation systems were tested to determine contaminant capture efficiencies. Adequate control of tank gas and vapor emissions is necessary for both employee exposure and fugitive air pollution considerations. In addition to videotaped smoke testing, novel tracer gas methods were employed to ascertain capture efficiencies before and after the application of engineering controls. Real-time infrared (IR) detection of sulfur hexafluoride (SF6) tracer gas permitted convenient adjustment of push- and pull-air flow for optimum capture efficiency. Capture efficiencies of about 93% or better were attainable for the 2.4by 4.9 m (8 by 16 ft) processing tanks. The careful control of cross-drafts was shown to be the most significant factor in achieving successful contaminant capture at tank liquid surfaces. Consequently, additional engineering controls were implemented to improve the effectiveness of the ventilation system, such as reducing the air flow rates and redirecting air flows in push-pull ventilation systems. In addition to reducing the disruptive cross-draft air turbulence, the ventilation modifications also significantly reduced noise levels and system energy requirements. The resulting appreciable improvements in push-pull capture efficiencies were quantified from the tracer testing. Since contaminant capture at the process tanks was improved, worker exposures were expected to be minimized correspondingly.

Exposure to Particulates and Fluorides and Respiratory Health of Workers in an Aluminum Production Potroom with Limited Control Measures

Occupational exposure to air pollutants and health status of potroom workers of an aluminum reduction plant in a developing country were studied and compared with those in developed countries. In this plant, the pots were constructed and installed without recommended gas collecting hoods or segmented side doors, and the workers did not use any respiratory protection. These conditions, combined with manual material handling and poor housekeeping, gave rise to fugitive air pollution generation. All 213 male potroom workers and 148 male control subjects were studied using air sampling, urinary fluoride measurement, ventilatory function testing, and a questionnaire on respiratory symptoms. On average, breathing zone respirable and total particulates in the potroom were 0.98 and 1.82 mg/m3, respectively. Stationary air sampling showed 0.93 mg/m3 of total fluoride, 2.09 mg/m3 of respirable particulates, and 7.59mg/m3 of total particulates. During an 8-hr shift, the average increase of urinary fluoride in the potroom workers (2.73mg/L) was significantly higher than that in the control group (0.39 mg/L). Workers in the potroom reported significantly higher frequency of respiratory symptoms than the control group. Potroom workers, especially nonsmokers, showed significantly greater decrease in their ventilatory function parameters during the shift than those of the control group; however, there was no difference between the basic ventilatory function of the two groups. The exposure to airborne particulates and the consequent respiratory symptoms as well as the daily increase of urinary fluoride values were generally higher in this plant than in similar operations in developed countries. This may be attributable to the fact that both process flow and machinery are often imported and assembled without the application of adequate engineering controls or complete understanding of proper safe work practices.

A new micromachined silicon high-accuracy pressure sensor

Abstract Sextant Avionique is currently developing a new family of micromachined silicon pressure sensors. The target accuracy is 10−4 full scale. Therefore, the basic principle uses a vibrating concept. A membrane is stressed by the pressure and this activates a vibrating beam, the frequency of which is related to the measured pressure. The sensing element is defined by three suitably micromachined silicon layers. The design is presented. This solution enables a vacuum to be sealed inside the silicon cell, thus diminishing the cost and the complexity of the packaging. Some realizations are presented. The metrological performance is then presented throughout the measurement range. This performance is compatible with the 10−4 full scale objective for the accuracy. These characteristics allow the utilization of the sensor for airborne air-data applications, as well as airborne engine-control applications, or groundbased applications where accuracy is needed, such as metrology.

Multi-criteria decision making in German automotive industry using fuzzy logic

In recent years, fuzzy logic technologies have been widely applied to control applications in engineering, where they are now considered an enabling technology for intelligent control systems. Fuzzy logic expedites the design of complex systems by allowing heuristic control strategies to be formulated by natural-language rules rather than mathematical models. Hence, the essence of fuzzy logic is its ability to put engineering expertise right into an algorithm. The domain of such a technology is not limited to control engineering, it can also be applied to incorporate complex decision making and the analysis of numerical data into non-control systems. This paper covers such an application, realized at Mercedes-Benz in Germany. For the optimization of the design process of truck components, such as gear boxes, the ‘maturity’ of a current component development needs to be evaluated. The objective is to reduce the amount of existing data of the development project to a single parameter, describing the overall maturity of the design.

Optically powered and interrogated rotary position sensor for aircraft engine control applications

A throttle level angle (TLA) sensing system is described that utilizes a capacitance based rotary position transducer that is powered and interrogated via light from a single multimode optical fiber. The system incorporates a unique GaAs device that serves as both a power converter and optical data transmitter. Design considerations are discussed, and the fabrication and performance of the sensor system are detailed.

Estimate of indicated torque from crankshaft speed fluctuations: a model for the dynamics of the IC engine

A contribution is made to the task of constructing a global model for the IC (internal combustion) engine. A robust submodel is formulated for the dynamics of the IC engine, where-in the engine is viewed as a system with input given by cylinder pressure and output corresponding to crankshaft angular acceleration and crankshaft torque. The formulation is well suited to closed-loop engine control and transmission control applications. In the model, cylinder pressure is deterministically related to net engine torque through the geometry and dynamics of the reciprocating assembly. The relationship between net engine torque and crankshaft angular acceleration is explain in terms of a passive second-order electrical circuit model with constant parameters. Experimental results confirm the validity of the model over a wide range of engine operating conditions, including transient conditions. It is concluded that the model provides a powerful tool for estimating average and instantaneous net engine torque based on an inexpensive noncontacting measurement of crankshaft acceleration, thus providing access to one of the primary engine performance variables. >

Transducer for Highly Critical Air Pressure Measurement

WITH even the most advanced technology there is usually room for some further improvement. Solartron Transducers' Series 3087 absolute air pressure transducer has, it is stated, been thoroughly flight proven in numerous avionics applications, for both military and civil aircraft, and is said to be generally accepted as offering a high accuracy and longterm stability. The minor influence of air density on the sensitivity of the 3087 vibrating cylinder sensor is claimed to be readily acceptable for most aviation purposes, and this model will continue to be the standard for the foreseeable future. For engine control applications, however, where density effect is marginally more significant, Solartron has now introduced the complementary Series 3088 transducer.

Optimal control applications in biomedical engineering—a survey

AbstractThe concept of a biological system operating in an optimal manner is intriguing. When this system (e.g. a human) is in a disease state, how can one administer appropriate optimal therapeutic treatment so that it can resume functioning with, hopefully, its original undiseased attributes? Biomedical engineering has a significant role to play in this area. This article illustrates some of the current attempts at improving therapy and the biomedical understanding of a normal or a disease state by using methods of optimal control theory such as the Pontryagin minimum principle, dynamic programming, and the calculus of variations.