Overview
Chapter 2 focuses on semiconductor-based electronic components, starting with the fundamentals of current flow in these materials It covers key active components such as diodes, bipolar transistors, and field-effect transistors (FETs), providing a qualitative overview of their operations along with analytical models for each device The chapter presents circuit application examples, including circuit diagrams and operational analyses, alongside a qualitative discussion of active element functionality in these circuits Additionally, it explores the integration of multiple active components, like transistors, which work together to achieve specific circuit functions, highlighting their availability as integrated circuits and their role in larger systems, such as microprocessors and essential components in modern automotive electronics.
Engineering readers are expected to have a basic understanding of three essential circuit components commonly found in larger circuits with electronic devices: resistors, capacitors, and inductors Those already knowledgeable about these components may choose to bypass the upcoming section, which focuses on developing simple models for each.
A resistor is a two-terminal component in electrical circuits that establishes a linear relationship between the voltage (v) across its terminals and the current (i) flowing through it The circuit symbol for an ideal resistor is illustrated in Fig 1.1.
For an ordinary resistor, the voltage/current model is given by v ẳ Ri whereRẳresistance of the resistor
The two parameters that are key in selecting a resistor for a circuit application are its resistanceR and its maximum power rating.
A capacitor is a two-terminal circuit component made up of two conducting electrodes separated by an insulating material When integrated into a circuit, a capacitor accumulates electric charge, resulting in a positive charge on one electrode and a negative charge on the other.
The voltage between the two terminals v is related to the chargeQ for a linear capacitor by the following
Q ẳ Cv whereCẳcapacitance of the capacitor.
To establish a relevant circuit model for voltage and current, one can differentiate the voltage charge equation with respect to time, resulting in the equation \( i = C \frac{dv}{dt} \) This model will consistently apply to any linear capacitor within electronic circuits throughout the book.
FIG 1.1 Resister circuit symbol and model.
FIG 1.2 Simplified capacitor configuration and circuit symbol.
Electronic Fundamentals
Microcomputer Instrumentation and Control
Chapter 3 focuses on microprocessors, detailing the fundamental architecture that also applies to microcontrollers The complexity of integrated circuits in microprocessors and microcontrollers has significantly advanced since the first edition of this book Alongside hardware discussions, the chapter also covers the software instructions that govern the operation of these digital devices.
The earliest automotive microprocessors were programmed using assembly language, a specific language for each microprocessor, despite the availability of various high-level languages At the time of this eighth edition, assembly language programming has become obsolete Initially, high-level compiler-type languages produced less computationally efficient programs for automotive control systems compared to those written in assembly language.
Modern programming utilizes efficient high-level languages and development systems like Autosar To illustrate the functionality of individual microprocessor components and their interaction with software, Chapter 3 presents exemplary assembly language programming Each assembly command directly controls fundamental microprocessor components and can often be expressed through Boolean algebra Additionally, Chapter 3 discusses the high-level programming languages employed in today's automotive electronic systems, with a focus on Autosar.
The creation of a new vehicular electronics system requires careful planning of its hardware architecture It is essential that the Microprocessor Controller (MPC) possesses adequate computational power and speed to meet the system's performance demands Additionally, all input and output components must be either sourced from existing devices or specifically designed to achieve the required performance standards.
The Basics of Electronic Engine Control
Chapter 3 focuses on microprocessors, detailing the fundamental architecture that also applies to microcontrollers The complexity of integrated circuits in microprocessors and microcontrollers has dramatically increased since the first edition of this book This chapter not only covers the hardware aspects of these digital devices but also explains the software that governs their operation.
The earliest automotive microprocessors were programmed using assembly language, which was specific to each microprocessor, despite the availability of various high-level programming languages At the time of writing this eighth edition, assembly language is no longer in use, as high-level compiler-type languages often produced less computationally efficient programs for automotive control systems compared to their assembly language counterparts.
Programming in today's automotive industry utilizes advanced high-level languages and development systems like Autosar To illustrate how individual microprocessor components interact with software, Chapter 3 presents exemplary assembly language programming, as each command directly influences fundamental microprocessor operations Additionally, many assembly language commands can be expressed in Boolean algebra Chapter 3 also covers the high-level programming languages employed in modern automotive electronic systems, with a focus on Autosar.
The creation of a new vehicular electronics system entails multiple stages, with a focus on system hardware architecture It is crucial for the incorporated MPC to possess adequate computational power and speed to meet the system's peak performance demands Additionally, all input and output components must be either chosen from available devices or specifically designed to achieve the necessary performance standards.
In Chapter 3, it is essential to select appropriate interface electronics that connect the system controller to the input/output components These electronics must either be sourced from existing circuits or specifically designed to fulfill the performance requirements of the system.
After developing the system architecture and hardware configuration, the next step is to create the software for its control Chapter 3 outlines fundamental Model Predictive Control (MPC) operations and provides assembly-level commands to facilitate understanding of advanced software development Before writing the software, algorithms for system operation must be crafted, with examples discussed in Chapter 3 and other sections that cover design theory and performance evaluation Appendices A and B detail the essential analytic procedures for algorithm development, which often include modeling the vehicular system controlled by MPC-based electronics System performance can then be assessed through computer simulations using advanced tools like MATLAB/SIMULINK Typically, the algorithms are tested in a prototype system, often utilizing a portable computer to emulate the intended MPC Software revisions are evaluated through experimental testing on automotive test tracks, and once finalized, the software can be stored in read-only memory (ROM) within the MPC-based electronics.
The packaging of electronic systems in production vehicles can vary, with one common method being the assembly of individual integrated circuits and electronic components, such as resistors, on a printed circuit board In advanced applications, the entire electronic system can be integrated into a single high-density integrated circuit, showcasing the capabilities of modern fabrication technologies.
Chapters four through the conclusion of the book explore the integration of electronics into key physical and mechanical components of vehicles Every vehicle is built around fundamental elements such as the body, suspension, steering, powertrain, braking, and lighting systems In modern vehicles, electronics are embedded within all these critical components, with the engine segment of the powertrain being the first to adopt electronic controls The powertrain encompasses the engine, transmission, and wheel drive mechanism, including the differential.
Chapter 3 provides a detailed overview of a specialized vehicular computer designed for various control and measurement applications, distinguishing it from general-purpose computers like laptops This digital system utilizes inputs from electronic sensors and switches activated by the vehicle, generating output signals that operate electromechanical devices (actuators) or display measurement data for the driver.
An MPC-based vehicular electronic control system operates through a stored program, with all control programs housed in ROM Chapter 2 discusses traditional circuits and their functionality for implementing digital memory, such as ROM In Chapter 3, simplified block diagrams of MPC-based electronic systems are presented, illustrating earlier configurations to clarify the fundamental processes involved in vehicular computer applications compared to modern systems.
This article discusses algorithms for operations performed by vehicular computers, focusing on digital filters and digital control algorithms for closed-loop feedback control, including proportional (P), proportional-integral (PI), and proportional-integral-derivative (PID) control laws Chapter 3 elaborates on the theory of these control systems, referencing Appendices A and B Additionally, it introduces limit-cycle control, a switched (on-off) control mechanism that activates the actuator based on the relationship between an input variable and defined switching levels The chapter also covers essential functions in vehicular systems, such as table-lookup interpolation for data derived from vehicular measurements.
Modern software development, particularly with frameworks like Autosar, is essential for programming the complete set of algorithms and logic operations necessary for electronic systems in vehicles Chapter 3 provides an overview of Autosar tailored for automotive applications, while in-depth details about this computer language are explored in other publications aimed at programmers seeking to master its capabilities.
Digital Powertrain Control Systems
Chapter 4 introduces the first electronic-controlled vehicular system, focusing on engine control, which serves as the prime mover in the vehicle powertrain This topic is discussed separately to maintain consistency with previous editions of the book The shift to electronic control marked the beginning of integrating electronic systems into various vehicular functions The primary motivation for this transition was the need to comply with government regulations on exhaust emissions and the long-term goal of meeting stringent emission standards outlined in this chapter.
This chapter provides qualitative insights into the basics of electronic engine control, along with analytic models and performance evaluation However, it does not cover the practical elements of contemporary powertrain control, which will be discussed in Chapter 6.
This chapter explores the impact of engine control variables, environmental factors, and vehicle parameters on regulated gas emissions, highlighting the role of catalytic converters and electronic controls in meeting regulatory standards Chapter 4 focuses on the fundamental concepts of emission control across various operating conditions, offering a simplified overview of electronic engine control systems with practical examples It includes dynamic models of engine performance and exhaust emissions to develop exemplary control laws, such as a hypothetical idle speed control (ISC) system based on system theory principles Additionally, a qualitative description of the topics is provided for readers without a mathematical background.
Chapter 6 provides a comprehensive overview of analytic modeling and analysis for a complete powertrain control system, highlighting the essential roles of sensors and actuators in the electronic control of vehicular systems, with specific references to electronic engine control mechanisms.
Chapter 4 focuses on sensors and actuators, clearly distinguishing the fundamentals of electronic engine control from the modeling and analysis of modern powertrain control, thereby facilitating a more straightforward understanding of the latter.
Vehicle Motion Controls
Chapter 5 focuses on sensors and actuators, offering a comprehensive overview of their modeling and performance analysis, which are essential components in electronic control systems for vehicles Every electronic control system, including those related to powertrain, braking, steering, and suspension, relies on specific sensors and actuators discussed in this chapter The content is organized into two main sections to facilitate understanding.
The section on sensors focuses on those related to engine control, highlighting specific sensors like exhaust gas oxygen and knock sensors that are exclusive to this function Additionally, it discusses sensors that, while primarily used for engine control, also serve other vehicular systems, such as angular position and pressure sensors These sensors can be easily explained and modeled for a single application, which in this context is engine control, as detailed in Chapter 5.
Measuring relevant variables in systems outside the exemplary models from Chapter 5 typically requires modifications in materials, component parameters, physical geometry, and fabrication methods However, the operation and modeling of sensors in non-engine systems are adequately addressed by the descriptions in Chapter 5 Detailed theories regarding the functionality of these sensors in non-engine control applications are elaborated in the associated chapter, which also presents the analytic model of the sensor based on discussions from Chapter 5.
When developing an analytic model for a sensor, it's essential to discuss the underlying physics of its operation, often requiring a review of relevant theories For instance, sensors utilizing magnetic fields can be modeled through fundamental concepts from electromagnetic field theory Many sensor applications involve measuring time-varying variables, necessitating dynamic models In some cases, the output model is represented by an equivalent circuit that includes inductance or capacitance components While readers with an engineering background may find this analysis straightforward, non-engineering readers can gain a qualitative understanding of sensor operation through accessible explanations.
The article discusses various sensors that extend beyond engine control, highlighting the solid-state angular-rate sensor and acceleration sensor, which play crucial roles in vehicle motion control and enhancing vehicle stability Additionally, it mentions the vehicle-heading sensor, which determines the vehicle's direction relative to true or magnetic north.
Chapter 5 explores electronic subsystems such as radar, lidar, and optical image sensors, which play a crucial role in enhancing vehicle safety through features like blind spot detection and automatic braking systems Radar sensors measure the distance and relative speed between an antenna and an object, while electronic cameras utilize a lens system and light sensor array to capture and process images of objects within their field of view This chapter provides an in-depth explanation and model for electronic cameras, highlighting their significance in advanced vehicle safety systems.
Chapter 5 explores the actuator section, focusing on devices used in engine control applications, such as solenoids and ignition coils Solenoids serve as electromagnetic devices that can precisely control fuel delivery in fuel injectors and operate valves for regulating fluid flow and pressure, playing a crucial role in vehicle motion control systems like brakes Additionally, ignition coils generate the high voltage necessary for creating sparks at spark plug electrodes in gasoline engines, igniting the fuel/air mixture at the optimal moment in the combustion cycle The models and explanations of these solenoids are relevant to all applications discussed throughout the book.
Electric motors are crucial electromagnetic actuators with diverse applications, ranging from side view mirror adjustments to driving hybrid and electric vehicles Chapter 5 delves into the qualitative operation of electric motors, focusing primarily on their theoretical underpinnings It develops analytic models for various motor types, facilitating performance analysis through calculations of motor torque and power based on electric sources Additionally, circuit models are introduced to connect performance with the excitation generated in the drive circuit, managed by the motor controller, which is further explored in the powertrain control chapter.
Chapter 5 covers single and polyphase induction motors, detailing the torque versus speed models for specific excitation currents It explains the methods for controlling these motors and develops a model illustrating the relationship between motor rotational speed, applied current, and torque load.
The brushless DC motor features a rotor that rotates in sync with the excitation frequency This motor's speed is controlled by generating excitation at a frequency that matches the desired rotation speed, achieved through a digital motor control system and power electronic components.
DC motors and analytic models and performance analysis are presented.
Stepper motors are specialized motors that move in precise angular increments, advancing one step for each pulse of excitation current received This article explores the operational principles of stepper motors and their various applications across different industries.
Vehicle Communications
Chapter 6 focuses on the complete vehicular powertrain, encompassing the traditional engine, transmission, and drive axle coupling of conventional vehicles, while also addressing hybrid and electric vehicles It begins by detailing digital control electronics both qualitatively and quantitatively, building on the electronic engine control concepts introduced in Chapter 4 This section emphasizes practical applications of digital engine control electronics, supported by the development of analytic models for the control system, referencing the basic discrete-time system theory outlined in Appendix B.
Engine control strategies aim to regulate exhaust emissions and enhance fuel economy while ensuring compliance with government regulations on pollutant gases The focus is on optimizing engine performance to not only meet but exceed the standards outlined in Chapter 4.
Digital engine control offers significant advantages by adapting to various operating modes such as start-up, warm-up, acceleration, deceleration, and cruising, while also considering environmental factors like ambient air pressure and temperature This technology can adjust to changes in vehicle parameters over time, ensuring compliance with emission standards for a designated mileage As an adaptive control system, digital engine control guarantees optimal engine emission performance throughout its lifespan.
Contemporary engines feature variable valve timing (VVT), also known as variable valve phasing (VVP), which enhances volumetric efficiency and improves engine performance while adhering to emission standards The implementation mechanism for VVP, along with its actuator, is detailed in Chapter 5 This chapter also discusses the control subsystem for VVP and develops relevant analytic models Additionally, the dynamic response characteristics of a VVP system are crucial for managing rapid RPM changes, with the dynamic models utilized to analyze the system's performance.
The idle speed control (ISC) subsystem is a crucial component of electronic engine control, designed to optimize engine operation at minimal fuel consumption during idle conditions It maintains a predetermined idle speed when the vehicle is stationary, whether due to driver choice or traffic signals, eliminating the need for engine restarts Additionally, when a vehicle is descending a slope, the ISC ensures that the engine operates efficiently without requiring power to sustain the desired speed The operational theory of the ISC subsystem is detailed, accompanied by the development of analytic models for its configuration Performance analysis reveals that the ISC functions as an adaptive control system.
As of now, several vehicles incorporate advanced engine starting systems that work alongside Idle Stop Control (ISC) to reduce fuel consumption when the vehicle is stationary These systems allow the engine to shut off during prolonged stops, enabling quick restarts with a simple application of the throttle, which facilitates rapid acceleration ISC helps maintain idle RPM until the engine is automatically turned off, leading to significant fuel savings, especially in urban traffic conditions This automatic start/stop technology is often found in hybrid vehicles, contributing to their efficiency.
This chapter discusses electronic ignition control, focusing on ignition timing, which is the crankshaft's angular position in relation to top dead center (TDC) during the compression stroke Additionally, it provides a qualitative overview and a partial analytical model of a closed-loop automatic ignition control system.
This chapter provides an overview of the electronic control mechanisms in automatic transmissions and the mechanical connection to the drive wheel axles, such as the differential It includes a concise review of the mechanical components, accompanied by illustrations, and offers qualitative explanations along with analytical models for these components, including the torque converter Additionally, it details the gear ratio selection methods and the actuators involved in electronic control, as well as the mechanisms and actuators related to torque converter lockup in electronically controlled automatic transmissions.
Chapter 6 focuses extensively on hybrid electric vehicles (HEVs), detailing the physical configurations of the two primary types: series and parallel HEVs The section includes block diagrams illustrating each HEV type and provides insights into their operational mechanisms Additionally, it develops analytic models for the electric components of the HEV powertrain, building on the electric motor concepts discussed in Chapter 5.
Performance analysis utilizes analytic models to explain the control mechanisms of Hybrid Electric Vehicles (HEVs) This control encompasses various functions, including the selection between the internal combustion (IC) engine and the electric motor as the primary power source During deceleration or braking, energy conservation is achieved by converting the electric motor into a generator, which stores the generated electric power in the vehicle's battery Chapter 6 details the mechanisms that enable HEVs to achieve superior fuel economy compared to similarly sized and weighted vehicles powered solely by IC engines.
The performance analytic models relate the electric motor torque and power to this excitation.
Chapter 6 delves into the operation of a hybrid electric vehicle (HEV) powered by an induction motor, detailing the analytic models and the electric excitation voltage necessary for propulsion when the internal combustion engine is off During this electric motor operation, power is sourced from the vehicle's storage batteries, which maintain a relatively constant voltage that is incompatible with the alternating current (AC) voltages needed by the drive motor The chapter elucidates the mechanisms for generating the required motor excitation voltages to meet the power and speed demands under various driving conditions, supported by exemplary circuit and block diagrams illustrating voltage conversion in HEVs Additionally, the chapter concludes with an overview of purely electric vehicles (EVs), highlighting their components, which share similarities with those in HEVs, but notably lack an internal combustion engine.
Diagnostics
Chapter 7 explores vehicle dynamic motion and its electronic control through various subsystems, starting with an overview of vehicle dynamics in relation to a fixed earth coordinate system Key subsystems involved in motion control are advanced cruise control, antilock braking systems, electronic suspension, electronic steering control, and traction control.
Certain components from the subsystems outlined in Chapter 7 are also utilized in other chapters For instance, the automatic braking control for individual wheels, integral to the antilock brake system, contributes to the enhanced stability system discussed in Chapter 10, which focuses on vehicle and occupant safety While antilock braking is related to vehicle safety and could have been included in Chapter 10, it is featured in Chapter 7 due to its primary function of ensuring optimal braking performance.
The traditional cruise control system is designed to help drivers maintain a consistent speed by automatically regulating the engine throttle, rather than relying on the accelerator pedal This system allows for a more relaxed driving experience, as it takes over speed control for gasoline-fueled vehicles.
This article explores an analytical model that examines the vehicle forces necessary for matching drive wheel torque and road force to sustain vehicle speed Key forces considered include tire rolling resistance, aerodynamic drag, and gravitational effects when traversing inclines A simplified linear model is utilized to illustrate the performance of a cruise control system, initially presented through continuous-time analog models The study evaluates how this basic cruise control system responds to changes in road slope, analyzing performance across various control laws.
Chapter 7 delves into the workings of a modern digital control system for vehicles, focusing on the development of discrete-time analytic models derived from continuous-time models, as outlined in Appendix B It also covers the creation of discrete-time models for closed-loop control systems commonly utilized in vehicle digital control The section includes a performance analysis of a digital cruise control system in response to changes in set point speed However, a notable limitation of cruise control arises when vehicles navigate downward slopes, where the throttle's closed position results in minimal engine power, and the friction forces may fall short of countering the gravitational pull, leading to potential speed regulation issues.
This limitation is overcome in an advanced cruise control system that is explained in this chapter.
This chapter explores an advanced cruise control system that features automatic braking to manage situations where the vehicle might accelerate with the throttle closed It details the system's configuration, operation, and analytical models, while also examining the essential sensors and actuators that comprise the cruise control system Furthermore, the chapter addresses potential performance limitations associated with these components and proposes methods to mitigate them Block diagrams of representative cruise control systems are also included to support the relevant system models.
Modern vehicle speed control systems have seen significant advancements, particularly in automatic braking for collision avoidance, as discussed in Chapter 10, which focuses on vehicle safety This chapter highlights how safety-driven automatic braking can be integrated into a vehicle's motion control system, enhancing its cruise control capabilities The decision to cover this advanced level of speed control in Chapter 10 is rooted in the overarching goal of improving safety in contemporary vehicles.
This chapter focuses on antilock braking systems (ABS), highlighting their significant enhancement of vehicle braking performance on low-friction surfaces, such as ice It begins with an overview of brake systems and their functions, addressing the challenges of reduced braking effectiveness due to low road/tire friction The text explains how ABS improves braking while allowing for normal driver input and maintaining steering control Additionally, it details the operation of ABS, emphasizing the automatic control of brake pressure in hydraulic brake systems.
This chapter discusses analytic models that explore the relationship between tire/road friction and vehicle motion variables, highlighting the impact of road surface conditions, such as dry, wet, or icy surfaces, on friction forces during vehicle deceleration Additionally, it covers the friction model related to lateral forces that affect steering and the vehicle's lateral stability Furthermore, the chapter explains the role of Anti-lock Braking Systems (ABS) in enhancing braking efficiency and maintaining directional control under low-friction conditions.
The Anti-lock Braking System (ABS) has diverse applications in vehicles, including traction control and Electronic Vehicle Stability (EVS) While traction control is explored qualitatively in this chapter, the discussion on EVS is more appropriately placed in Chapter 10, where the analytical models align closely with safety-related vehicular electronics.
Autonomous Vehicles
The vehicle's movement across the Earth's surface is analyzed using a continuous-time second-order differential equation model, which is linearized for easier evaluation of suspension performance These equations are then transformed into transfer functions, as detailed in Appendix A.
The road surface generates random motions that affect vehicle dynamics, which can be analyzed through the suspension system's response to these variables By utilizing statistical models, the performance of the suspension system can be evaluated, revealing the relationship between key properties and the quantitative aspects of ride and handling This analysis results in a table of optimal suspension parameter values, although enhancing ride quality may compromise handling performance, and vice versa This section also discusses electronically controlled suspension systems, which can adjust parameters through actuators and control strategies to optimize ride and handling based on driving conditions, prioritizing safety during challenging maneuvers like cornering on rough roads Control laws for these adaptive systems allow for optimization of ride quality on smooth, straight roads, demonstrating the versatility of electronically controlled vehicular subsystems.
This chapter discusses power steering, highlighting the evolution from traditional systems that utilized a control valve linked to the steering shaft to modern vehicles that employ electronic control Notably, one of the first production vehicles to feature electronic steering control marked a significant advancement in automotive technology.
Chapter 7 discusses four-wheel steering (4WS), a vehicle system where the driver controls the front steering wheels, enhanced by power steering assistance Additionally, the rear wheels are steerable and are controlled electronically, improving maneuverability and handling.
This article discusses simple linear analytic models for four-wheel steering (4WS) vehicles, represented through state variable equations It outlines two levels of vehicle dynamic motion: the first, a simplified model with minimal lateral dynamics and a two-dimensional state vector, and the second, a more complex model that incorporates lateral dynamics with a four-dimensional state vector The analysis examines the vehicle's motion in response to 4WS input at both complexity levels An illustrative example demonstrates the dynamic response of a typical passenger car during a lane change maneuver, comparing 4WS with conventional two-wheel steering.
The components of the 4WS example vehicle play a crucial role in electronically controlled automatic steering systems While this topic is explored in depth in Chapter 12, which focuses on autonomous vehicles, the concept of automatic steering is also relevant in the context of automatic parallel parking and lane tracking technologies, both of which are currently available on the market.
Chapter 8 focuses on vehicular instrumentation, highlighting the evolution from traditional mechanical and hydraulic systems to modern electronic instrumentation Historically, instrumentation provided essential measurements such as vehicle speed, fuel quantity, engine oil pressure, and electric system status, displayed directly on the instrument panel The appendices detail the fundamental components of electronic instrumentation systems, including sensors that generate electrical signals related to the measured variables and display devices that present this information to drivers In contemporary vehicles, these displays often issue visual and audio warnings when variables exceed safe limits, indicating the need for repairs or fluid additions Additionally, the chapter addresses signal processing methods, emphasizing the digital implementation of these processes in modern vehicles.
Chapter 8 focuses on signal processing techniques specific to vehicle instrumentation measurements, starting with single-variable systems and progressing to multi-variable measurements using a single digital system, such as a specialized computer In modern vehicles, data for instrumentation and other systems are transmitted through a dedicated in-vehicle network (IVN), which is crucial for various electronic systems While Chapter 8 addresses the instrumentation aspect of the IVN, a more in-depth discussion of the IVN is found in Chapter 9, highlighting its significance in vehicular communications.
This article discusses the application of a common instrumentation computer for processing signals from various sensors to multiple displays, illustrated through a block diagram It highlights a list of automotive sensors and switches used for vehicle monitoring, noting that many of these sensors are analog The necessity of A/D conversion for digital signal processing is addressed, with further details provided in Chapter 3 Additionally, the chapter explains the electronic mechanism for selecting one of several signals for processing, such as multiplexing, and presents quantitative examples of typical signal processing algorithms.
Chapter 8 extensively covers vehicular display technology, starting with an analytical model of traditional electromechanical displays, specifically galvano meters, which are still utilized in some modern vehicle instrument panels.
Chapter 8 explores different electro-optic display devices utilizing various materials and configurations, detailing the fabrication of arrays of electro-optic elements These advancements enable the creation of displays that present information in alphanumeric formats Additionally, modern vehicles now incorporate arrays that can display pictorial formats, similar to those found on laptops and smartphones.
This article explores modern display technologies, focusing on the fundamental electro-optic principles that govern their operation It provides a detailed explanation of the physical principles and theoretical models for various display types, including light-emitting diodes (LED), liquid-crystal displays (LCD), and vacuum fluorescent displays (VFD) The discussion includes an analytical model that relates optical output to electrical input, as well as the mechanisms for adjusting display brightness based on ambient light conditions Additionally, the article evaluates the relative advantages and disadvantages of each electro-optic technology.
Electro-optic display technology, commonly known as flat panel display (FPD), utilizes a two-dimensional array of small pixels to produce high-resolution images Each pixel's light excitation is controlled to create images combined with alphanumeric data, as detailed in Chapter 8 This chapter also presents analytic models that quantitatively explain FPD technology A significant application of FPDs is in electronic maps, which are dynamically updated by an instrumentation computer as a vehicle travels Modern vehicles often incorporate GPS navigation systems that display the vehicle's position on the map using FPD technology.
Modern technology allows for multiple types of flat panel displays (FPDs) in vehicles, with a focus on minimizing driver distraction In aviation, these multiple FPDs are referred to as "glass cockpits." Additionally, touch screen (TS) capabilities have been introduced in FPDs, enabling user interaction with devices like smartphones.
Touch sensing (TS) technology plays a crucial role in modern vehicular applications by enabling intuitive user interaction with flat panel displays (FPDs) This technology operates through analytic models that illustrate how a user's touch on a TS-enabled FPD serves as input to the vehicle's instrumentation system Essentially, a TS-capable FPD functions similarly to a large array of switches integrated into the instrument panel, allowing drivers to effortlessly control various vehicle systems.
The touch screen (TS) detects user input based on the specific location touched on the screen, utilizing multiple fingers if necessary Chapter 8 delves into the sensing mechanisms that identify the contact point, providing analytic models and circuit diagrams for clarity The TS operates alongside the flat panel display (FPD), where symbols are presented that correspond to specific inputs when touched This section outlines the operational details of the TS as an instrumentation input device.
Chapter 9 focuses on vehicle communication systems, highlighting their critical roles in vehicle operation, navigation, and information sharing, alongside traditional entertainment functions It introduces the concept of the in-vehicle network (IVN), which consists of various systems characterized by differing data rates, protocols, and costs The chapter details four commonly used IVNs currently integrated or nearing completion in modern vehicles, utilizing communication media such as wires, coaxial cables, and optical fibers A comprehensive overview of the physical layers and communication protocols is provided, explaining how data is transmitted between electronic subsystems within the vehicle Additionally, the chapter addresses in-vehicle communication through wireless methods, covering both theoretical aspects and practical applications of these systems.
“controller area network” (CAN), “flex ray,” “local interconnect,” (LIN) and “media-oriented systems transport” (MOST).
In any In-Vehicle Network (IVN), key challenges include data exchange rates, message capacity, and overall system costs Additionally, network control is crucial to ensure that all connected modules can access the system, especially when multiple modules attempt simultaneous access, a process known as "arbitration." This chapter addresses these challenges for each IVN and its corresponding protocol, detailing the specific message formats associated with each protocol.
IVNs enhance vehicular system performance by integrating data from various subsystems, which broadens the analytical model and expands the system's operational capabilities This interconnectedness improves the precision and accuracy of the controlled variables, ultimately leading to more efficient vehicle functionality.
In Chapter 9, the article explores the essential role of transceivers in In-Vehicle Networks (IVNs), which facilitate data transmission and reception across the network It provides detailed representations and explanations of the circuitry for each IVN, along with the development of analytic models that describe their operation Additionally, the article includes waveforms that illustrate the individual signal models associated with these circuits.
Modern technology enables a wireless connection between cell phones and vehicle electronic systems, allowing for hands-free usage This setup routes incoming vocal signals to the vehicle's loudspeaker, enabling drivers to receive calls without physically handling their phones Depending on the system's configuration, outgoing audio can be captured by either the cell phone's microphone or a dedicated microphone in the vehicle Additionally, the system enhances driving safety by allowing drivers to make phone calls using voice commands.
Advanced voice recognition software enables drivers to verbally dial phone numbers and even compose and send text messages Depending on the system configuration, this technology may be integrated into either the cell phone or the vehicle's digital electronics This chapter discusses the hardware necessary for establishing an in-vehicle wireless connection between cell phones and other digital devices, while the specifics of the voice recognition software are not covered in this book.
Chapter 9 delves into the theory behind cell phone communication, focusing on coding schemes such as CDMA and TDMA It provides a detailed exploration of Code Division Multiple Access (CDMA), supported by relevant analytic models and specific examples to clarify this complex process Additionally, the chapter discusses modulation techniques essential for the cell phone radio link, including example circuitry for modulation and demodulation, along with accompanying analytic models These modulation techniques are designed to reduce the impact of variations in carrier signal strength caused by multipath propagation and the movement of cell phones.
The "time domain multiple access" (TDMA) technique is a multiple user scheme for cell phones that allocates distinct time slots within each operational cycle to specific user pairs This chapter provides an explanation and modeling of the TDMA method.
The cell phone infrastructure consists of interconnected fixed transceiver and antenna stations, known as cell towers, which facilitate communication between users It includes controlling systems that ensure a stable connection, especially for users in vehicles transitioning between different cell towers.
A somewhat complex control is required to maintain a given connection and is described here.
Chapter 9 explores the use of Bluetooth technology as a short-range wireless link for connecting subsystems or devices to vehicle electronic systems This connection utilizes a unique method known as frequency hopping (FH), which involves 79 potential carrier frequencies within the microwave section of the electromagnetic spectrum The Bluetooth devices change their carrier frequency in a pseudorandom manner, ensuring a stable wireless connection by synchronously switching frequencies once paired.
This article discusses various short-range wireless vehicle communication applications utilizing Bluetooth or similar technologies One notable application includes the ability to transmit vehicle maintenance data to adjacent diagnostic systems Additionally, the chapter highlights several other promising uses for this wireless communication system.
Digital Audio Broadcasting (DAB) is a V2I communication system that begins its broadcast from a satellite, primarily serving entertainment purposes It caters to both fixed and mobile receivers, enhancing the listening experience across various platforms.
DAB utilizes a sophisticated multiple carrier link system known as orthogonal frequency-division multiplexing (OFDM) A comprehensive overview of OFDM, including analytic models, block diagrams, and representative circuit diagrams, is provided in Chapter 9 This system employs discrete Fourier transforms and inverse discrete Fourier transforms, as detailed in Appendix B, to effectively multiplex various broadcast channels Additionally, Chapter 9 includes practical examples of OFDM to enhance the understanding of this complex process.
Chapter 10 focuses on vehicular electronic safety systems designed to prevent or reduce injuries to occupants during accidents It also explores recent advancements in technology aimed at accident prevention.
Occupant protection systems, particularly airbags, play a crucial role in enhancing safety alongside seatbelts This chapter provides an updated overview of airbag technology, detailing the operational principles of airbag systems It also differentiates between accident scenarios that necessitate airbag deployment and other sudden vehicle movements, such as hitting a large pothole.
The article qualitatively describes representative physical configurations through illustrative figures and presents block diagrams of associated electronic systems, along with analytic models for various components These models are integrated to conduct a performance analysis of exemplary airbag systems It emphasizes the critical role of sensors and signal processing in accurately detailing crash scenarios that necessitate airbag deployment Additionally, it highlights that improper airbag deployment, triggered by non-injury incidents, can obstruct the driver’s forward view and potentially lead to accidents.
Chapter 10 reviews the evolution of airbag technology, highlighting early configurations and their circuit diagrams to illustrate advancements in occupant safety It discusses significant improvements in crash detection through enhanced sensing and signal processing technologies, featuring various exemplary algorithms that demonstrate these advancements.
Chapter 10 delves into "blind spot detection" (BSD), highlighting the challenges drivers face in observing their surroundings under various driving conditions It explores advanced technologies such as radar, lidar, and electronic cameras that aid in identifying vehicles or objects outside the driver's field of view The section also covers signal processing techniques for detecting potential hazards and presents analytic models related to BSD systems, including image recognition Additionally, it discusses key BSD algorithms that enhance safety on the road.
Chapter 10 discusses "automatic collision avoidance systems" (ACAS), which enhance the sensing capabilities of blind spot detection (BSD) systems ACAS utilizes electronic monitoring to assess the surrounding traffic and obstacles, employing advanced signal processing to predict potential collisions When a collision is deemed imminent and the driver does not take evasive action, ACAS intervenes by automatically braking the vehicle This system integrates components of anti-lock braking systems (ABS) to effectively manage the brakes, and in some vehicles, it also activates seatbelt pretensioning to enhance passenger safety.
Chapter 10 presents analytical models that elucidate how the ACAS identifies imminent collisions, incorporating representative calculations based on sensor data It also introduces additional models that illustrate vehicle dynamics when automatic braking is engaged.
In addition to automatic braking, collision avoidance systems utilizing automatic steering are available in certain levels of autonomous vehicles A more detailed discussion on this mechanism can be found in Chapter 12, while this chapter offers only a brief reference to the topic.
Chapter 11 focuses on diagnosing vehicle issues through electronic systems that aid technicians in repairs Vehicles are equipped with electronic diagnostic capabilities, and service-bay systems, such as those used in auto dealerships, also play a crucial role Since the inception of digital control systems, these systems have included self-diagnostic features that store fault codes in memory when a malfunction occurs These fault codes can be transferred to service-bay systems for effective vehicle problem diagnosis The chapter includes examples of representative fault codes, highlighting the types of component malfunctions that can be identified, and emphasizes the importance of standardizing these codes as recommended by SAE practices.
Chapter 11 highlights key diagnostic procedures utilized by service technicians with a service-bay diagnostic tool This tool features a computer-like display that guides technicians through a series of steps presented in flow charts The chapter includes various examples to demonstrate the procedures for diagnosing specific component malfunctions effectively.
Vehicles must comply with governmental regulations that mandate specific self-diagnostic capabilities known as on-board diagnostics (OBD), which monitor malfunctions affecting exhaust emissions A critical aspect of OBD is misfire detection, which identifies improper combustion caused by issues like incorrect air/fuel mixtures or faulty spark plugs The Environmental Protection Agency (EPA) requires that any detected misfires trigger a warning message to alert drivers, prompting necessary powertrain repairs when misfires surpass a designated threshold.
Chapter 11 introduces a misfire detection method that utilizes the sensing and analysis of crankshaft instantaneous angular speed fluctuations caused by misfires This approach is grounded in an analytical model of crankshaft rotational dynamics, which facilitates the signal processing of data from a sensor that measures these fluctuations.
Chapter 11 discusses how crankshaft angular speed can indicate misfire, detailing a model-based misfire detection system that includes a comprehensive block diagram, signal processing algorithms, and criteria for establishing the misfire diagnostic code Furthermore, the chapter presents experimental results showcasing the system's effectiveness in meeting regulatory requirements for misfire detection.
Chapter 11 explores the application of artificial intelligence, particularly expert systems, in diagnosing vehicle system issues It details how service technicians rely on established knowledge from automotive experts to conduct diagnostic procedures Additionally, the chapter outlines the development process of an expert system for vehicle diagnostics, where technicians input symptoms and fault codes to identify problems Examples are provided to illustrate the practical use of these vehicular expert systems by technicians.
Chapter 12 focuses on the ongoing research and development of autonomous vehicles, aiming to create driverless cars These vehicles will rely on advanced computer systems and automated subsystems to operate independently The chapter outlines the essential actions performed by human drivers that the computer must replicate to ensure safe and efficient vehicle operation.
Autonomous vehicles are categorized into various levels based on the degree of driver involvement needed At the lowest level, drivers must actively monitor their surroundings and make standard driving decisions Conversely, at the highest level, the vehicle operates completely independently, requiring no driver intervention.
All essential automatic systems for autonomous vehicles have been developed, with most discussed in earlier chapters However, one crucial automatic subsystem that has not been addressed is automatic steering, which is vital for the functionality of autonomous vehicles.
Automatic steering technology is currently implemented in a limited capacity in certain production vehicles, primarily featuring automatic parallel parking and lane tracking capabilities This article explores analytic models for automatic steering, focusing on parallel parking as a case study, and provides an in-depth description of the necessary hardware components, including their physical configurations and models Additionally, it presents a detailed example of steering deflection and includes a computer simulation of an automatic parallel parking scenario, with performance results illustrated graphically.
Chapter 12 outlines the block diagram of an autonomous vehicle, illustrating its automatic systems and essential sensors It emphasizes the need for a comprehensive sensor suite that enables the vehicle to assess its environment with a full 360-degree view, including vehicular radar, lidar, and camera systems equipped with image identification software, as previously discussed in Chapter 10 regarding blind spot detection For a fully autonomous vehicle, accurate information on lane tracking, vehicle, and obstacle detection is crucial The chapter also details the performance requirements of this sensor system to ensure the safe operation of autonomous vehicles.
Autonomous vehicles must not only sense their environment but also possess advanced software that evaluates this data and makes decisions akin to those of human drivers This software is crucial for making short-term predictions about environmental changes that necessitate immediate action from the control system, marking it as a key focus of research and development in high-level autonomous vehicles While the necessary hardware is already in place, developing the software demands extensive testing for various scenarios that could require decision-making Additionally, successful and safe operation of autonomous vehicles is widely recognized to depend on a robust communication infrastructure for Vehicle-to-Infrastructure (V2I) and Vehicle-to-Vehicle (V2V) communications, as detailed in Chapter 12.
Hardware redundancy is crucial for the safe operation of autonomous vehicles, as it ensures that any failure or significant performance degradation of a driving component does not compromise safety To mitigate hazards, backup components are essential for replacing failed parts Chapter 12 emphasizes the importance of reliably detecting and isolating these failures, highlighting a specific case of an automatic steering actuator failure that utilizes hardware redundancy.
Once the essential software and hardware redundancy, along with the communication infrastructure, are in place, autonomous vehicles can effectively operate This chapter illustrates an example of an autonomous vehicle's journey, assuming the completion of these critical system components It covers the navigation process for such trips, highlighting the role of digital maps as discussed in Chapter 9 One navigation method allows users to input their desired destination, while the vehicle utilizes GPS to determine its starting location The optimal route from the starting point to the destination is a standard feature of GPS and electronic mapping technologies.
Chapter 12 concludes that, despite the established automatic navigation capabilities and the presence of necessary vehicular systems, routine autonomous vehicle operation currently lacks software and hardware redundancy, a robust communication infrastructure, and adequate governmental regulation.
Semiconductor devices play a crucial role in modern electronics, encompassing components such as diodes, transistors, and integrated circuits Diodes, including Zener diodes and light-generating diodes, are essential for rectification and communication applications Transistors, particularly field-effect transistors (FETs), are fundamental in amplification and switching Integrated circuits, which house operational amplifiers and various logic circuits, utilize feedback mechanisms for enhanced performance Key components like summing mode amplifiers, comparators, and phase-locked loops are vital in signal processing Additionally, digital circuits rely on the binary number system and combinatorial logic circuits, such as AND gates, to perform complex computations efficiently.
OR Gate 70 NOT Gate 70 Boolean Algebra 71
Understanding Automotive Electronics http://dx.doi.org/10.1016/B978-0-12-810434-7.00002-8
Copyright # 2017 Elsevier Inc All rights reserved 23
Exemplary Circuits for Logic Gates 71 Combination Logic Circuits 75 Logic Circuits with Memory (Sequential) 77 R-S Flip-Flop 77
D Flip-Flop 79 Timer Circuit 80 Synchronous Counter 83 Register Circuits 83 Shift Register 84 Digital Integrated Circuits 86 The MPU 87
This chapter serves as an introductory guide for readers with minimal electronics knowledge, aiming to simplify future discussions on automotive electronics control systems It covers essential electronic devices and circuits relevant to automotive instrumentation and control, including semiconductor devices, analog circuits, digital circuits, and the basics of integrated circuits.
Electronic circuits are constructed using active circuit devices like diodes and transistors, which are made from semiconductor materials These materials, in their pure form, possess conductivity that lies between that of good conductors, such as copper, and insulators, like mica While good conductors allow current to flow easily with low voltage, insulators restrict current flow, resulting in minimal or no current Semiconductors, therefore, exhibit a unique conductivity that enables them to function effectively in electronic devices, commonly referred to as semiconductor or solid-state devices.
Transistors and diodes are crucial semiconductor devices in automotive electronics and serve as the foundational components for nearly all modern integrated circuits These devices are primarily constructed from silicon or germanium, with other materials like gallium arsenide also being utilized The conductivity of these semiconductors is altered through intentional infusion with impurities.
The conductivity of pure semiconductors can be predictably adjusted by introducing controlled amounts of specific impurities This process, known as doping, involves adding impurities to silicon to modify its electrical properties.
Boron and phosphorus serve as impurity source materials to modify the conductivity of silicon in semiconductor manufacturing The introduction of boron creates a p-type semiconductor, while the addition of phosphorus results in an n-type semiconductor.
To grasp the functioning of transistors and diodes, it's essential to understand electric conductivity in n-type and p-type semiconductors Electric current flows due to the movement of electrons in response to an applied electric field, generated by voltage at the external terminals This electric field, a key component of electromagnetic field theory, is represented by a vector known as electric field intensity (E) While advanced details of this theory are not covered, simplified models are discussed in later chapters For semiconductor properties, we present a basic model where electric field intensity varies with applied voltage and inversely with the distance between electrodes, with electrons originating from the material's atomic structure.
For a basic understanding of conductivity, it is helpful to refer toFig 2.1that depicts a relatively long, thin slab of semiconductor material across which a voltage is applied.
The electric field intensity, represented as the vector E, is directed along the x-axis In this context, vectors are denoted with a bar over their symbols, such as in the case of electric field intensity E When a voltage v is applied across a pair of conducting electrodes, typically made of copper (Cu), the electric field intensity E remains approximately constant throughout the length of the thin semiconductor material.
E ẳ E^ x where^xẳunit vector in thexdirection.
FIG 2.1 Illustration of current conduction in semiconductor.
Also shown inFig 2.1is the current density vectorJ, which is also an x-directed vector The current density vector is proportional to the electric field intensity:
The current density \( J \) is defined as the current per unit cross-sectional area and is influenced by the material's conductivity \( \sigma \) Under the assumption of a nearly constant electric field \( E \), the magnitude of \( J \) remains constant.
A c (2.2) whereAcis the cross-sectional area of the slab in they,zplane The reciprocal of conductivity is known as the resistivityρof the material: ρ ẳ 1 σ (2.3)
The "band theory of electrons" is fundamental to understanding electron flow in materials, as it explains that electrons are confined to specific energy ranges known as bands Each electron occupies a discrete energy level within these bands, with a limit on the number of electrons per level For current flow to occur, electrons must move to unoccupied energy levels in response to an electric field; however, electrons in lower energy bands are fully occupied and cannot contribute to conductivity In contrast, electrons in the conduction band, which are less tightly bound, can move freely when an electric field is applied In materials like silicon (Si), doping with phosphorus introduces excess free electrons, transforming the material into an "n-type" semiconductor with enhanced conductivity compared to pure Si.
The valence band, the second lowest energy band in semiconductors like silicon (Si), is nearly filled with energy levels Doping Si with a p-type impurity, such as boron, creates additional energy levels within this band, resulting in a p-type semiconductor In this material, electrons can transition to these new energy levels under an electric field, facilitating current flow This p-type semiconductor effectively behaves as if it has an excess of positively charged particles known as “holes.” Current flow in semiconductors is modeled using these fictitious holes, which respond to applied fields In n-type materials, electrons are the “majority carriers” while holes are the “minority carriers,” and this relationship is reversed in p-type materials.
Doping a semiconductor alters the balance between holes and electrons, yet a fundamental relationship between these densities remains constant irrespective of doping levels For instance, in an intrinsic semiconductor like silicon (Si), the concentrations of holes and electrons are initially equal.
“free” electrons and holes (since each free electron leaves a “hole” in the valence band for an intrinsic semiconductor), we denote this concentrationniẳ1.510 10 /cm 3
Doping silicon with p-type or n-type impurities alters the concentrations of charge carriers In thermal equilibrium, the relationship between electron density (n) and hole density (p) is expressed by the equation np = n²i.
A fundamental aspect of semiconductor physics influencing the electrical characteristics of semiconductor components is the application of voltage When a voltage (V) is applied to a semiconductor slab, it generates an electric field, denoted by the electric field intensity vector (E).
In semiconductor materials, an external electric field induces movement of electrons and holes, characterized by their mean velocity vectors, \( v_e \) and \( v_h \) The velocities are determined by the equations \( v_e = \mu_e E \) and \( v_h = \mu_h E \), where \( \mu_e \) represents the electron drift mobility and \( \mu_h \) denotes the hole drift mobility.
These mean velocities yield electron and hole current densitiesJeandJh, respectively:
J h ẳ pq v h whereqis the charge on an electron (1.610 19 coulomb) These relationships will appear in models for various components in this text.