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About this book

As the complexity of automotive vehicles increases this book presents operational and practical issues of automotive mechatronics. It is a comprehensive introduction to controlled automotive systems and provides detailed information of sensors for travel, angle, engine speed, vehicle speed, acceleration, pressure, temperature, flow, gas concentration etc. The measurement principles of the different sensor groups are explained and examples to show the measurement principles applied in different types.

Table of Contents

Frontmatter

Basics of mechatronics

The term “mechatronics” came about as a made-up word from mechanics and electronics, where electronics means “hardware” and “software”, and mechanics is the generic term for the disciplines of “mechanical engineering” and “hydraulics”. It is not a question of replacing mechanical engineering by “electronification”, but of a synergistic approach and design methodology. The aim is to achieve a synergistic optimization of mechanical engineering, electronic hardware and software in order to project more functions at lower cost, less weight and installation space, and better quality. The successful use of mechatronics in a problem solution is dependent upon an overall examination of disciplines that were previously kept separate.
Hans-Martin Heinkel, Klaus-Georg Bürger

Architecture

Over the last three decades, tremendous progress has been made in automotive engineering. Modern injection and exhaust- gas treatment systems drastically reduced pollutants in the exhaust gas, while occupant-protection and vehicle stabilization systems improved safety on the road. Much of this success is due to the introduction of electronically-controlled systems. The proportion of these systems used in cars increased continuously. The requirements of safety and environmental compatibility, but also the demand for comfort and convenience functions, will increase yet further and this will in no small part be achieved through the use of electronics. Up to around 90 % of innovations in the motor vehicle will be realized by electronics and microprocessor-controlled systems. The networking of these electronics creates the prerequisite for having this wide variety of electronic systems integrated within the complete vehicle system to form a whole. However, this results in a complexity that can only be overcome at considerable expense.
Dieter Kraft, Stefan Mischo

Electronic control unit

Digital technology furnishes an extensive array of options for open and closed-loop control of automotive electronic systems. A large number of parameters can be included in the process to support optimal operation of various systems. The control unit receives the electrical signals from the sensors, evaluates them, and then calculates the triggering signals for the actuators. The control program, the “software”, is stored in a special memory and implemented by a microcontroller. The control unit and its components are referred to as hardware. The Motronic control unit contains all of the algorithms for open and closed-loop control needed to govern the engine-management processes (ignition, induction and mixture formation, etc.).
Martin Kaiser, Ulrich Schaefer, Gerhard Haaf

Basic principles of networking

With the tremendous speed at which computer technology is advancing, the number of electronic systems in use is increasing more and more. This growth is also continuing in automotive engineering. However, this also means that the complexity of an overall system (the vehicle in this case) is on the increase. Individual systems such as engine management have been improved over the last few years. However, innovations are mainly achieved by means of interaction between several individual systems. The individual components need to be networked so that the multitude of information that is managed by the individual systems can also be used elsewhere throughout the system. Different communication systems are used depending on requirements (e.g. transmission reliability, fault tolerances, costs).
Stefan Mischo, Heiko Holtkamp, Alexander Leonhardt, Peter Häussermann, Rainer Constapel, Jörn Stuphorn, Norbert Löchel, Stefan Powolny, Hanna Zündel

Aotomotive networking

Electrical and electronic systems in motor vehicles are often not independent of each other but influence and complement each other. For this reason, signal lines were used in previous injection and ignition systems in order to simplify communication between these two systems. However, the increasing number of electronic systems rapidly increased the demand for and the scope of the information that was being exchanged. The number of signal lines and plug connections that is required increased accordingly, meaning that the technology that has so far been used was approaching the limit of its capability.
Stefan Mischo, Jörn Stuphorn, Rainer Constapel, Heiko Holtkamp, Alexander Leonhardi, Peter Häussermann, Norbert Löchel, Stefan Powolny, Hanna Zündel

Bus systems

In 1991 the CAN bus (Controller Area Network) was the first bus system to be introduced to a motor vehicle in mass production. It has since established itself as the standard system in the automotive sector, but the CAN bus is also commonly used as a field bus in automation engineering in general. In imitation of other network types, such as the local area network (LAN), wide area network (WAN) or personal area network (PAN), this bus system was given the name, CAN.
Stefan Mischo, Jörn Stuphorn, Rainer Constapel, Peter Häussermann, Alexander Leonhardi, Heiko Holtkamp, Norbert Löchel, Stefan Powolny, Hanna Zündel

Automotive sensors

The term sensor has become common, as in the past 20 to 40 years measuring gages have also come into use in consumer applications (e.g. motor vehicle and domestic appliance technology). Sensors – another term for measuring detectors or measuring sensors – convert a physical or chemical (generally nonelectrical) variable ϕ into an electrical variable E; this process often also takes place over further, non-electrical intermediate stages.
Erich Zabler, Wolfgang-Michael Müller, Claus Bischoff, Christian Pfahler, Peter Weiberle, Ulrich Papert, Christian Gerhardt, Klaus Miekley, Roger Frehoff, Martin Mast, Bernhard Bauer, Michael Harder, Klaus Kasten, Peter Brenner, Frank Wolf, Johann Riegel, Reinhard Neul, Thomas Wahl, Uwe Konzelmann, Harald Emmerich, Gerald Hopf, Günter Noetzel, Hartmut Kittel, Christian Bauer, Wolfgang Welsch, Stefan Finkbeiner

Sensor measuring principles

There is a great number of sensors at work in motor vehicles. They act as the sensory organs of the vehicle and convert input variables into electrical signals. These signals are used in control and regulation functions by the control units in the engine-management, safety and comfort and convenience systems. Various measuring concepts are applied, depending on the task.
Erich Zabler, Christian Gerhardt, Klaus Miekley, Roger Frehoff, Martin Mast, Bernhard Bauer, Michael Harder, Klaus Kasten, Peter Brenner, Frank Wolf, Johann Riegel, Wolfgang-Michael Müller, Claus Bischoff, Christian Pfahler, Peter Weiberle, Ulrich Papert, Reinhard Neul, Thomas Wahl, Uwe Konzelmann, Harald Emmerich, Gerald Hopf, Günter Noetzel, Hartmut Kittel, Christian Bauer, Wolfgang Welsch, Stefan Finkbeiner

Sensor types

Application
Engine-speed sensors are used in enginemanagement systems for Measuring the engine speed and Determining the crankshaft position (position of the pistons.
The engine speed is calculated from the interval between the speed sensor’s signals.
Erich Zabler, Wolfgang-Michael Müller, Claus Bischoff, Christian Pfahler, Peter Weiberle, Ulrich Papert, Christian Gerhardt, Klaus Miekley, Roger Frehoff, Martin Mast, Bernhard Bauer, Michael Harder, Klaus Kasten, Peter Brenner, Frank Wolf, Johann Riegel, Reinhard Neul, Thomas Wahl, Uwe Konzelmann, Harald Emmerich, Gerald Hopf, Günter Noetzel, Hartmut Kittel, Christian Bauer, Wolfgang Welsch, Stefan Finkbeiner

Electric Actuators

Actuators (final-control elements) form the interface between the electronic signal processor (data processing) and the actual process (mechanical motion). They convert the low-power signals conveying the positioning information into operating signals of an energy level adequate for process control. Signal transducers are combined with amplifier elements to exploit the physical transformation principles governing the inter relation ships between various forms of energy (electrical – mechanical – fluid – thermal).
Rudolf Heinz, Robert Schenk

Electrohydraulic Actuators

Electrohydraulic actuators form the interface between electrical signal processing (data processing) and the system process (mechanics). They convert the low-power command signals into an actuating force with the increased power required for the process.
D. Fornoff, T. Müller, D. Grauman, E. Hendriks, T. Laux, A. Schreiber, S. Schumacher, W. Stroh

Electronic Transmission Control

In complicated traffic situations, unfamiliar surroundings, or poor weather conditions (e.g., heavy rain, snow, or fog), manual gear changing can distract car drivers to such an extent as to create situations that are difficult to control. This also applies to the annoying, incessant process of engaging and disengaging the clutch when driving in stop-and-go traffic. Automatic transmissions with electronic control assist drivers in these and other traffic situations so that they can concentrate fully on the road conditions and what is happening around them.
D. Fornoff, T. Müller, D. Grauman, E. Hendriks, T. Laux, A. Schreiber, S. Schumacher, W. Stroh

Modules for Transmission Control

Modules are compact function and constructional units that enable different standardized components to be integrated with the minimum component and space requirements and simplified interfaces. Hydraulic, electronic, and electrohydraulic modules are available to suit the level of integration required.
D. Fornoff, T. Müller, D. Grauman, E. Hendriks, T. Laux, A. Schreiber, S. Schumacher, W. Stroh

Antilock Braking System (ABS)

In hazardous driving conditions, it is possible for the wheels of a vehicle to lock up under braking. The possible causes include wet or slippery road surfaces, and abrupt reaction on the part of the driver (unexpected hazard). The vehicle can become uncontrollable as a result, and may go into a slip and/or leave the road. The antilock braking system (ABS) detects if one or more wheels are about to lock up under braking and if so makes sure that the brake pressure remains constant or is reduced. By so doing, it prevents the wheels from locking up and the vehicle remains steerable. As a consequence the vehicle can be braked or stopped quickly and safely.
Friedrich Kost, Thomas Ehret, Jochen Wagner, Ulrich Papert, Frank Heinen, Peter Eberspächer, Jürgen Schuh, Heinz-Jürgen Koch-Dücker, Frank Niewels

Traction Control System (TCS)

Critical driving situations can occur not only while braking, but also whenever strong longitudinal forces should be transferred at the contact area between the tire and the ground. This is because the transferable lateral forces are reduced by this process. Critical situations can also occur when starting off and accelerating, particularly on a slippery road surface, on hills, and when cornering. These kinds of situations can overtax the driver not only causing him/her to react incorrectly but also causing the vehicle to become unstable. The traction control system (TCS) solves these problems, providing the vehicle remains within the physical limits.
Friedrich Kost, Jürgen Schuh, Heinz-Jürgen Koch-Dücker, Frank Niewels, Thomas Ehret, Jochen Wagner, Ulrich Papert, Frank Heinen, Peter Eberspächer

Electronic Stability Program (ESP)

Human error is the cause for a large portion of road accidents. Due to external circumstances, such as an obstacle suddenly appearing on the road or driving at inappropriately high speeds, the vehicle can reach its critical limits and it becomes uncontrollable. The lateral acceleration forces acting on the vehicle reach values that overtax the driver. Electronic systems can make a major contribution towards increasing driving safety.
Friedrich Kost, Jürgen Schuh, Heinz-Jürgen Koch-Dücker, Frank Niewels, Thomas Ehret, Jochen Wagner, Ulrich Papert, Peter Eberspächer, Frank Heinen

Automatic brake functions

The possibilities of today’s electronic brake systems go far beyond the tasks for which they were originally designed. Originally the antilock braking system (ABS) was only used to prevent the wheels of a vehicle from locking up and therefore to ensure the steerability of the vehicle even during emergency braking. Today, the brake system also controls the distribution of the brakingforce. The electronic stability program (ESP), with its ability to build up brake pressure independently of the position of the brake pedal, offers a whole series of possibilities for active brake intervention. The ESP is intended to assist the driver by applying the brakes automatically and to therefore provide the driver with a higher level of comfort and convenience. Some functions, however, enhance the vehicle safety since automatic brake application during an emergency results in shorter braking distances.
Friedrich Kost, Jürgen Schuh, Heinz-Jürgen Koch-Dücker, Frank Niewels, Thomas Ehret, Jochen Wagner, Ulrich Papert, Frank Heinen, Peter Eberspächer

Hydaulic modulator

The hydraulic modulator forms the hydraulic connection between the master cylinder and the wheel-brake cylinders and is therefore the central component of electronic brake systems. It converts the control commands of the electronic control unit and uses solenoid valves to control the pressures in the wheel brakes.
Friedrich Kost, Jürgen Schuh, Heinz-Jürgen Koch-Dücker, Frank Niewels, Thomas Ehret, Jochen Wagner, Ulrich Papert, Frank Heinen, Peter Eberspächer

Sensotronic brake control (SBC)

Sensotronic brake control (SBC) is an electrohydraulic brake system that combines the functions of a brake servo unit and the ABS (antilock braking system) equipment, including ESP (electronic stability program). The mechanical operation of the brake pedal is redundantly measured by the actuator unit and transmitted to the control unit. There, control commands are calculated according to specific algorithms and passed to the hydraulic modulator where they are converted into pressure modulating operations for the brakes. If the electronics fail, a hydraulic fallback system is automatically available.
Bernhard Kant

Overview of common-rail systems

The demands placed on diesel-engine fuel-injection systems are continuously increasing. Higher pressures, faster switching times, and a variable rate-of-discharge curve modified to the engine operating state have made the diesel engine economical, clean, and powerful. As a result, diesel engines have even entered the realm of luxuryperformance sedans.
Felix Landhäußer, Rainer Heinzmann, Mikel Lorente Susaeta, Andreas Rettich, Klaus Ortner, Werner Brühmann, Ulrich Projahn, Michael Heinzelmann, Ralf Wirth, Peter Schelhas, Meike Keller, Sandro Soccol, Herbert Strahberger, Helmut Sattmann, Thilo Klam, David Holzer, Andreas Koch, Patrick Mattes, Thomas Kügler, Martin Grosser, Andreas Michalske, Günter Driedger, Walter Lehle, Wolfgang Schauer

High-pressure components of common-rail systems

The high-pressure stage of the common-rail system is divided into three sections: pressure generation, pressure storage, and fuel metering. The high-pressure pump assumes the function of pressure generation. Pressure storage takes place in the fuel rail to which the rail-pressure sensor and the pressure- control and pressure-relief valves are fitted. The function of the injectors is correct timing and metering the quantity of fuel injected. High-pressure fuel lines interconnect the three sections.
Felix Landhäußer, Helmut Sattmann, Rainer Heinzmann, Mikel Lorente Suseata, Andreas Rettich, Werner Brühmann, Klaus Ortner, Ulrich Projahn, Michael Heinzelmann, Ralf Wirth, Peter Schelhas, Meike Keller, Sandro Soccol, Herbert Strahberger, Thilo Klam, David Holzer, Andreas Koch, Patrick Mattes, Thomas Kügler, Martin Grosser, Andreas Michalske, Günter Driedger, Walter Lehle, Wolfgang Schauer

Electronic Diesel Control (EDC)

Electronic control of a diesel engine allows fuel-injection parameters to be varied precisely for different conditions. This is the only means by which a modern diesel engine is able to satisfy the many demands placed upon it. The EDC (Electronic Diesel Control) system is subdivided into three areas, “Sensors and desired-value generators”, “Control unit”, and “Actuators”.
Felix Landhäußer, Mikel Lorente Suseata, Werner Brühmann, Rainer Heinzmann, Andreas Rettich, Klaus Ortner, Ulrich Projahn, Michael Heinzelmann, Ralf Wirth, Peter Schelhas, Meike Keller, Sandro Soccol, Herbert Strahberger, Helmut Sattmann, Thilo Klam, David Holzer, Andreas Koch, Patrick Mattes, Thomas Kügler, Martin Grosser, Andreas Michalske, Günter Driedger, Walter Lehle, Wolfgang Schauer

Active steering

The development of vehicle steering systems is characterized by the consistent introduction of hydraulic servo assist and the replacement of ball-and-nut-type steering in the car by the easier and more inexpensive rack-and-pinion steering. Recently, electromechanical power steering has been displacing hydraulic power steering in small and lightweight cars. By law, however, pure “steer-by-wire” technology is not yet permitted in motor vehicles. European Union safety regulations still require a mechanical connection between the steering wheel and the wheels of the vehicle.
Wolfgang Rieger

Drive and adjustment systems

Application
Power windows have mechanisms that are driven by electric motors. There are two types of systems in use (Fig. 1). The available installation space assumes a prominent place among the criteria applied in determining which system to install.
Rod linkage regulator mechanism: The drive motor pinion engages with a quadrant gear, which is connected to a rod linkage. The use of this type of window regulator mechanism is decreasing.
Flexible cable mechanism: The drive motor turns a cable reel, which operates a flexible cable mechanism.
Rainer Kurzmann, Günter Hartz

Heating, ventilation and air conditioning

The vehicle’s heating, ventilation and air conditioning systems have the following tasks:
- Providing a pleasant climate for all occupants of the car at different outside temperatures (Fig. 1).
- Ensuring good visibility through all windows and the windshield.
- Creating an environment calculated to minimize driver stress and fatigue.
- More recent units use filters to remove particulate matter (pollen, dust) and even odors from the air.
Gebhard Schweizer

Vehicle security systems

Application
The internationally applicable ECE Regulation No. 28 specifies that acoustic signals produced by motor vehicles must maintain a uniform sound quality with no perceptible frequency fluctuations during operation. Operation is permitted only as a hazard warning function. In countries where this regulation does not apply, the acoustic signaling device is a wearing part subject to heavy use. The use of sirens, signal bells and the like is not permitted, nor is playing melodies by triggering sound generators in a given sequence. Signaling devices must be installed facing forward in the vehicle and must produce the signal at a sufficient loudness level at a distance of 2m. They are subjected to temperatures ranging from –40°C to +90°C and must be designed to be resistant to moisture, salt spray as well as mechanical shock and vibration. Elastic couplings must be used to decouple electric horns and fanfare horns from the vehicle body, as the horn would otherwise induce sympathetic oscillations in the adjacent bodywork. The resulting feedback would diminish both loudness level and tone quality. Both electric and electropneumatic horns and fanfare horns are sensitive to series resistors in their control circuits. When horns are installed in pairs, they should be triggered by relays. The warning produced by the impact horn is more conspicuous; therefore, it is the better choice for vehicles that are frequently used for long-distance overland truck traffic instead of fanfare horns. Alternatively, the fanfare horn is superior for city driving, as pedestrians often find the standard horn excessively loud and unpleasant. Both sets of requirements can be fulfilled by installing the two horn types together in a single system with a selector switch for city or overland traffic. Standard and fanfare horns both operate at standardized frequencies. High and low tones can be combined to produce a harmonious dualtone sound.
Jürgen Bowe, B. Kordowski, Andreas Walther, Jan Lichtermann

Electromagnetic compatibility (EMC) and interference suppression

Electromagnetic compatibility (EMC) consists of two elements. One is understood as the ability of a device to continue providing reliable service when exposed to electromagnetism from external sources. The second aspect focuses on electromagnetic fields generated by the same device; these should remain minimal in order to avoid creating interference that would impinge upon the quality of radio reception, etc. in the vicinity.
Wolfgang Pfaff

Fault diagnostics

The rise in the sheer amount of electronics in the automobile, the use of software to control the vehicle, and the increased complexity of modern fuel-injection systems place high demands on the diagnostic concept, monitoring during vehicle operation (on-board diagnosis), and workshop diagnostics (Fig. 1). The workshop diagnostics is based on a guided troubleshooting procedure that links the many possibilities of onboard and offboard test procedures and test equipment. As emission-control legislation becomes more and more stringent and continuous monitoring is now called for, lawmakers have now acknowledged on-board diagnosis as an aid to monitoring exhaustgas emissions, and have produced manufacturer- independent standardization. This additional system is termed the on-board diagnostic system.
Matthias Knirsch, Matthias Tappe, Bernd Kesch, Günter Driedger, Walter Lehle

Backmatter

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