Classification of Automotive Electronics

Powertrain electronics, safety, chassis electronics, and infotainment systems are the four major categories of automotive electronic systems. All vital electronic components and systems crucial for a vehicle's operation, safety, comfort, and entertainment fall within these categories.

Powertrain Electronics

The primary function of powertrain electronics is to oversee the engine, transmission, and assorted power-generating components, facilitating the vehicle's movement. Systems like the Engine Control Unit (ECU), ignition system, exhaust after-treatment system, engine cooling system and fuel injection system are encompassed within this category. Particularly, the ECU serves as the powertrain system's central component, overseeing and coordinating diverse subsystems to ensure fuel efficiency, peak performance and emission regulation.

Within hybrid and electric vehicles, the scope of powertrain electronics extends to encompass components like the Battery Management System (BMS) and the Traction Inverter or Starter Generator. These elements are responsible for managing battery usage, operating e-Machines, and overseeing energy recuperation processes.

Chassis Electronics

Systems within chassis electronics play a significant role in shaping the vehicle's driving dynamics. Such systems encompass Traction Control System (TCS), anti-lock braking systems (ABS), power steering mechanisms and Electronic Stability Control (ESC). Under diverse driving conditions, these systems improve the vehicle's stability, maneuverability, and overall performance.

Chassis electronics encompass tire pressure monitoring systems, suspension control systems, and various sensors that monitor chassis behavior. They play a pivotal role in preserving ideal vehicle behavior and offering valuable feedback to the driver.

Safety and Security Systems

Electronic systems dedicated to safety and security ensure the protection of both vehicle occupants and the vehicle itself. Systems within this category comprise seatbelt pre-tensioners, airbag controllers, alarm systems, advanced driver assistance systems (ADAS), and access control systems such as immobilizers and remote keyless entry.

Advanced vehicles integrate sophisticated safety systems including adaptive cruise control, lane departure warning, and collision detection systems. Utilizing an array of sensors, cameras, and radars, these advanced systems continuously monitor the vehicle's surroundings and proactively initiate measures to avert accidents.

Infotainment Systems

Vehicle infotainment systems aim to furnish both the driver and passengers with entertainment options and informative content. Incorporating traditional car stereo functionalities alongside rear-seat entertainment, navigation systems, voice recognition, smartphone connectivity, and internet access, these systems offer a comprehensive array of features.

The principal interface between the driver and the vehicle, contemporary infotainment systems deliver an extensive spectrum of information, encompassing vehicle status updates, navigation guidance, and management of audio and climate systems. With growing complexity and an abundance of features, these systems now seamlessly integrate functionalities such as mobile and Wi-Fi connectivity, real-time traffic updates, and even remote-control capabilities for specific vehicle features.

Grasping the categorization of automotive electronics lays the groundwork for understanding the interplay and collective functioning of various systems within a vehicle. This factor holds immense significance during the design and development phases, ensuring the creation of vehicles that are both efficient and enjoyable, while also prioritizing safety.

The Electrical Architecture of a Vehicle

At the core of all functionalities and operations within a vehicle lies its electrical architecture, governing everything from fundamental lighting to intricate drive systems. Incorporated within this architecture are essential components like the battery, and wiring harness, as well as an array of electronic control units (ECUs) and modules.

Role of the Battery

In the electrical architecture of a vehicle, the battery serves a crucial role. When the engine is inactive, it serves as the primary source of electrical energy within the vehicle, supplying the essential power required to initiate the combustion engine. Upon engine activation, the alternator typically furnishes the required electrical power, while the battery might absorb and retain surplus energy.

The 12V lead-acid battery is common in old vehicles, whereas there is an added small 48V battery in mild-hybrid electric vehicles (MHEVs). These vehicles intentionally select a battery voltage below hazardous thresholds, eliminating the need for intricate electrical insulation designs, and thereby significantly reducing costs. Hybrid electric and electric vehicles (HEVs and EVs) incorporate high-voltage battery packs, typically at 400V and above, in addition to the conventional 12V system. Along with starting the vehicles, the high-voltage batteries also power the electric motor(s). Hybrid electric vehicles (HEVs) commonly utilize NiMH cells for their high-voltage battery, whereas electric vehicles (EVs) opt for Lithium cells due to their superior energy and power density. The oversight of these high-voltage batteries is frequently handled by a Battery Management System (BMS), ensuring their safe and efficient operation.

Wiring Harness

The circulatory system of a vehicle’s electrical architecture is formed by the wiring harness. This intricate network comprises connectors, wires, and terminals, facilitating the transmission of both power and signals across the vehicle. Linking the battery's positive terminal and alternator to an array of loads such as motors, lights, heaters and controllers like ECUs, is the primary function of the wiring harness. To avoid additional cabling, return currents from the battery transmit through the vehicle chassis, which connects to the battery's negative terminal. However, in the electrical system, not everyone is directly grounded to the chassis. Several sensors and ECUs obtain their grounding individually, often through wiring connected to a distinct ECU.

From straightforward networks found in standard vehicles to exceedingly intricate systems present in luxury or extensively automated cars, the complexity of wiring harnesses can range widely. The wiring harness’s design must consider components like voltage drop, cost, current-carrying capacity, weight and dependability. Every vehicle is equipped with a fuse box containing fuses to safeguard the wiring harness from overcurrent due to damage. Protecting the wiring not the loads attached to it is the primary objective of the fuse.

ECUs and Modules

The Electronic Control Units (ECUs, different from the Engine Control Units sharing the same abbreviation) serve as the "brains" embedded within the vehicle's electrical framework. Within a vehicle, an ECU stands as an embedded system responsible for managing one or multiple electrical systems or subsystems.

Through communication buses, ECUs are communicating with each other. CAN (Controller Area Network) is the most widely used bus. Traditional architectures typically designate specific ECUs as masters, like the Body Control Module (BCM) or the Engine Control Unit, with other units functioning as slaves, awaiting directives from the master units. Examples of these slave units include the Door Zone Module, the Seat Zone Module, and the Battery Management Slaves. Within contemporary automobiles, the count of ECUs may exceed one hundred, contingent upon the vehicle's level of complexity.

Comprehending a vehicle's electrical architecture establishes a fundamental framework for delving deeper into the functionality and interplay of automotive electronic systems. With the progression of vehicle technology, the increasing complexity and significance of this architecture demands a more profound and holistic grasp of its essential elements and how they intertwine.

Importance of Power Electronics in Vehicles

A critical component of modern vehicles is power electronics. In the functioning of different electronic systems and the overall vehicle performance, power electronics plays a critical role. Utilizing sophisticated semiconductor technology like SIC MOSFETs or IGBTs, power electronic devices proficiently manage and transform electric power. In energy efficiency, voltage regulation and handling electric loads, they play an important role.

Voltage Regulation

In vehicles, voltage regulation is crucial as it manages a stable voltage supple to diverse electronic elements. In this aspect, the role of power electronic equipment is crucial. Within traditional vehicles, the alternator, overseen by an electronic voltage regulator, sustains the voltage necessary for charging the battery and powering the onboard electronics. The voltage supply from a vehicle's battery can exhibit significant fluctuations, notably when the starter generator initiates the combustion engine startup, drawing a substantial current that might cause the voltage to plummet to as low as 3V. Internal voltage regulators within ECUs manage the regulation from the battery voltage to either 5V or 3.3V. Their design must ensure survival through various battery voltage disturbances while maintaining the functionality of the electronics.

Within hybrid and electric vehicles, power electronics assume heightened significance. Components like DC/DC converters deliver hundreds of amperes, while onboard chargers manage power flow between high voltage (HV) and low voltage (LV) systems. Additionally, they convert AC power from the grid into DC power to charge the battery pack.

Energy Efficiency

The efficiency of vehicles, especially in hybrid and electric models, is notably enhanced by the substantial contribution of power electronics to energy utilization. Enabling precise management of electric motor functions, they optimize both torque output and overall efficiency.

Moreover, they facilitate regenerative braking, a process that transforms the energy typically dissipated as heat during braking into electrical energy, subsequently storing it in the vehicle's battery. Under the guidance of power electronics, this energy-recapturing system has the potential to enhance the vehicle's overall efficiency and extend the range of electric vehicles.

Electric Loads (Heaters, Fans, E-Machines)

Power electronic devices control and operate larger electrical loads such as heaters, fans, and e-machines (electric propulsion motors). Through precise load control, power electronics guarantee optimal performance, energy efficiency, and reliability.

For example, to manage high power levels efficiently, heaters in electric vehicles may utilize high-voltage power electronics. Likewise, power electronics regulate fans responsible for cooling the engine, battery, or other components. This control mechanism adjusts the fan speed according to the cooling requirements, effectively conserving energy.

In electric vehicles (EVs), e-machines stand as the most significant consumers, boasting power ratings that can extend up to 600kW. This equates to a potential draw of up to 750A current from an 800V battery. Designing power electronics capable of driving it with minimal power losses is of utmost importance. Controlling e-machines involves the utilization of 3-phase bridge modules constructed using SiC MOSFETs or IGBT transistors. These modules are mounted on a ceramic structure known for its exceptional thermal properties.

With the rising electrification of vehicles, the role of power electronics in vehicles is growing. A critical aspect for automotive engineers lies in comprehending their function and operational mechanisms, pivotal for the development of enhanced and dependable vehicle systems. Their role in automotive equipment is set to be even more critical in the future, with the development of more contemporary power electronic equipment and control tactics.

Sensors and Actuators

In automotive systems, actuators and sensors play crucial roles, forming the sequence between the electronic and physical realms within a vehicle. Enabling interaction between the vehicle's control systems and the physical environment, they oversee monitoring conditions and executing control actions.

Role and Basic Functions

To measure physical properties and transform them into signals, read by an electronic control unit (ECU), sensors are used. Within automotive systems, sensors oversee a multitude of parameters such as temperature, pressure, speed, position, and chemical composition, among other crucial factors. Offering instantaneous feedback to the ECU, this data is processed and utilized to govern various vehicle systems.

On the other hand, to perform physical actions based on input signals from the ECU, the devices used are actuators. Importantly, they transform electronic signals back into physical action. Utilized extensively across various applications including door mechanisms, engine control, seat adjustments, brake control, wiper and light beam control, sensors play a crucial role in adjusting physical parameters based on sensor inputs and control algorithms within different vehicle systems.

Sensor Examples: Speed Sensors, O2 Sensors

In automotive applications, speed sensors and oxygen (O2) sensors stand out as two prevalent examples of sensors frequently employed.

Typically, speed sensors are employed for measuring the rotation speed of diverse components like wheels, the engine crankshaft, and the transmission output shaft. Systems such as the Anti-lock Braking System (ABS) and Electronic Stability Control (ESC) heavily rely on wheel speed sensors. These sensors furnish essential data required to regulate individual wheel speeds during cornering and braking.

Figure 4: Wheel speed sensor in application

In engine management, oxygen sensors play an important role. They are positioned in the exhaust system of a vehicle and measure the oxygen amount in the exhaust gases. Utilizing this data, the ECU adjusts the air-fuel mixture for combustion within the engine, aiming to optimize efficiency and minimize harmful emissions. In contemporary vehicles, there's a common occurrence of having multiple O2 sensors to offer feedback, positioned both before and after the catalytic converter. This setup serves to enhance emission control significantly.

Figure 5: Oxygen sensors in application

Actuator Examples

There are two types of actuators in the Transmission Control Module. The motors function as pumps, ensuring the maintenance of appropriate transmission fluid pressure required for operation. Controlling the direction of transmission fluid pressure within the gearbox, valve solenoids play a crucial role in shifting gears into the correct position.

On the module, the actuators are managed by the Transmission Control Unit (TCU). However, TCU is not capable enough to decide when to shift gears. It gets the commands from the Engine Control Unit via CAN network.

In essence, sensors and actuators serve as the fundamental pillars of a responsive, efficient and safe automotive control system. With the integration of more advanced features in vehicles, like autonomous driving capabilities and advanced driver assistance systems (ADAS), there is a probable rise anticipated in both the significance and complexity of these components. Grasping their function and operational mechanisms constitutes a pivotal element within the realm of automotive electronics education.