Unlocking the Power of MEMS Sensors for Automotive Applications, for Smarter, Safer Vehicles
Sensors play a critical role in modern automobiles, ensuring safety, efficiency, and enhanced driving experiences. In fact, most of the critical systems in a vehicle rely on sensors to measure and monitor key parameters, which has become central factor in making our roads safer, lowering pollution and improving our driving experience.
Among the various sensor technologies, MEMS (Micro-Electro-Mechanical Systems) sensors stand out due to their precision, miniaturization, and versatility. MEMS sensors for automotive applications will be critical as the human driver increasingly relinquishes control to electronic systems, in tomorrow’s world of autonomous vehicles.
What are MEMS Sensors?
Microelectromechanical systems (MEMS) combine tiny mechanical parts, electrical devices, and electronic circuitry using integrated-circuit (IC) fabrication technologies. The structural features in these systems are quite small (ranging from 1 to 100 microns), allowing for greater integration within the limited spaces of modern vehicles.
MEMS sensors can detect changes in the environment, such as movement, pressure, and magnetic fields, and convert them into electrical signals.
Types of MEMS Sensors For Automotive Applications
1. Accelerometers
Accelerometers gauge both static (gravity) and dynamic (motion or vibration) acceleration. MEMS accelerometers typically operate based on one of two principles: either the movement of a mass or the piezoelectric effect.
Under the first principle, a weight is affixed to a spring. When accelerated, inertia endeavors to maintain the mass’s position, thereby exerting force on the spring, which produces an electrical signal proportional to the object’s motion.
In the piezoelectric-based principle, acceleration forces impact a microscopic crystalline structure, generating a corresponding voltage.
2. Gyroscopes
Gyroscopes detect angular changes. MEMS gyros typically use paired vibrating objects, such as a tuning fork. These vibrating objects tend to maintain their motion within the same plane. If the paired objects experience linear acceleration, they move together in the same direction without any noticeable difference in their motion.
However, when the tuning fork is rotated, each object experiences a force in opposite directions due to the Coriolis effect, causing them to move out of plane. These forces can be converted into output voltages that correspond to the speed of the angular change.
By detecting rotational movements, gyroscopes help maintain vehicle stability during sharp turns and ensure accurate navigation by complementing GPS data.
3. Pressure Sensors
MEMS pressure sensors evaluate the pressure difference across a silicon diaphragm. One side of the diaphragm holds a fixed reference pressure, while the other side is exposed to the environment being measured.
The pressure difference causes mechanical strain on the diaphragm, which can be detected by changes in the electrical resistance of the diaphragm materials due to the piezoresistive effect.
Pressure Sensors Critical in Tire Pressure Monitoring Systems (TPMS) and Engine Management. In TPMS, they ensure tires are properly inflated, enhancing safety and fuel efficiency.
In engine management, pressure sensors optimize fuel injection and turbocharger performance, improving engine efficiency and reducing emissions.
4. Magnetometers
A magnetometer measures the strength and direction of a magnetic field, used in navigation systems and electronic compasses.
A MEMS sensor typically utilizes the Lorentz force, which occurs when a charged particle (such as in an electrical current loop) moves through a magnetic field. The resulting mechanical deflection of the electrical structure, proportional to the strength of the field, can be detected either electronically or optically.
Magnetometer provide directional information, aiding in accurate vehicle positioning and navigation, especially in areas where GPS signals might be weak or unavailable.
5. Inertial Measurement Units (IMUs)
Inertial Measurement Units combine accelerometers, gyroscopes, and sometimes magnetometers to offer comprehensive motion data. They play a crucial role in advanced driver-assistance systems (ADAS) and autonomous driving technologies, facilitating precise tracking of vehicle movement and enhancing safety features such as lane departure warnings and adaptive cruise control.
6. Thermal sensors
Thermal sensors are designed to measure temperatures, and within MEMS, this sensing is commonly achieved using a resistance temperature detector. These detectors analyze variations in the electrical resistance of a thin layer of test material (such as platinum, germanium, or polysilicon) in reaction to temperature fluctuations.
7. Gas sensors
Gas sensors are utilized to evaluate the concentrations of gases like carbon dioxide and other volatile compounds. A range of detection technologies is employed, including electrochemical, pellistor, and photoionization methods.
8. Optical MEMS
Optical MEMS components are designed to both direct and detect light across a spectrum ranging from visible light to infrared wavelengths. These components utilize lens arrays and microscopic mirrors to collect and steer light, while the detection of light intensity is accomplished through photodiodes, which produce an electrical current upon exposure to light, or photoresistors, which undergo a change in electrical resistance in response to light.
Deployment of MEMS Sensors in Automobiles
MEMS sensors are extensively utilized in modern vehicles, with their range of applications continuously expanding. While separate sensor, control, and actuator modules were prevalent a few years ago, there’s now a trend toward integrating these functions into micro integrated packages.
CFSensor is a pioneer and the leading supplier of MEMS sensors in the automotive and consumer electronics industry. Due to this extensive system know-how, we can design MEMS technology for our customers to fit optimally to the respective application.
CFSensor provides MEMS sensors for a wide range of automotive applications.
Safety systems
- Used for microchip gas pressure detection, to do continuous monitoring of the pressure when the microchip is working, with the microchipl thermal runaway management.
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XGZC6201 Current Sensor
- ±0.5% linearity over full temperature range
- Fast output step response time: 1.8μs
- 240kHz signal bandwidth
- 5.0V DC power supply
- -40°C to 105°C operating temperature
- Rated current detection range: (bidirectional) --- ±10A~±120A
- Detects AC and DC current signals
- Power-independent fixed output mode
- Extremely stable quiescent output voltage
- Built-in reference voltage output
- Installed in the liquid cooling system water inlet and outlet pipes, detecting coolant pressure, for battery thermal management system.
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- As an accessory of corrosion-resistant pressure digital display, it is used for detecting corrosive liquid or gas media in semiconductor, battery and other production equipment.
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Engine/emissions management systems
- For use in gasoline evaporative control systems (EVAP), can be mounted on fuel pumps, activated carbon canisters or fuel tanks to detect fuel vapor pressure.
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XGZP6182 Boost Pressure Sensor
This product is made with advanced MEMS principles, and the core technology is piezoresistive based MEMS pressure sensor chip and high performance signal conditioning AISC chip is of high quality and precise packaging. Using experienced and reliable technology on calibration, compensation and protection , Fast response speed, high reliability, good stability, it’s a cost-effective sensor product. The evaporative fuel pressure sensor is a real-time pressure measurement in the fuel tube, which ensures that the carbon canister system works properly and reduces emissions.
- Mounted on engine flywheel housing to detect crankshaft signal disk speed.
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Camshaft Position Sensor XGZR6191
Using small-volume, low-cost samarium cobalt magnets as the magnetic field source of the product; Using electromagnetic pure iron with low coercivity and high permeability to improves the utilization rate of permanent magnet magnetic field and response time; The glazed wire resistant to high pulse voltage is used as the source of the product signal.
Finally, the coils, permanent magnets and magnetically conductive pure iron are assembled and injection-molded. The process is simple, the product injection molding consistency is good, the size is small, and the cost is low.
- Camshaft phasing detection on engine gear housing.
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Crankshaft Position Sensor XGZR6192
Adopting well-known brand Hall components can ensure product output accuracy and quality reliability. Using samarium cobalt magnets as the constant magnetic field of the product can guaranteed performance and high stability. Adopt one-piece injection molding structure scheme, reduce the number of parts and shorten the process flow, reduce material and production costs.
- Engine intake pressure or atmospheric pressure detection.
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- Engine oil pressure detection, brake pressure detection.
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- Differential exhaust gas pressure detection for GPF or DPF pressure differentials.
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Vehicle comfort systems
- Automotive seat airbag pressure detection, used in automotive seat lumbar support system.
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Benefits of MEMS Sensors in Automobiles
MEMS sensors offer several advantages, including high precision and accuracy, essential for critical safety and performance applications. Their miniaturization allows for integration into compact spaces within vehicles. They consume low power, contributing to overall vehicle efficiency.
Additionally, MEMS sensors are cost-effective and exhibit durability and reliability in harsh automotive environments, ensuring long-term performance.
Future Trends and Developments
The future of MEMS sensors for automotive applications in automobiles looks promising, especially with the advent of autonomous vehicles. While some MEMS devices such as micromirrors provide support to autonomous vehicles (AVs), new ground must be broken.
Advances in MEMS technology and manufacturing will lead to even more precise and reliable sensors. Integration with the Internet of Things (IoT) will enhance connected vehicle capabilities, while emerging applications in electric and hybrid vehicles will further boost their importance.
MEMS sensors are indispensable in modern automobiles, providing critical data for safety, performance, and driver assistance systems. Their precision, miniaturization, and versatility make them ideal for a wide range of applications. As automotive technology continues to evolve, MEMS sensors will play an increasingly vital role in shaping the future of transportation.
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