Refrigerant leak detection in vehicles

CO₂ and propane sensors for automotive safety

100%
of currently used refrigerants potentially harm the environment
Only natural refrigerants provide long-term sustainability, if we can harness them safely
30k
ppm CO₂ can be exceeded in parked cars
Slow R744 leaks can raise CO₂ levels to potentially hazardous concentrations
Grams
of propane can create an explosive environment
A usual R290 charge can release enough gas to form a flammable layer on the floor of a small garage

Refrigerant safety concerns in automotive HVAC

The adoption of alternative refrigerants like R744 (CO₂) and R290 (propane) in vehicle air conditioning systems is increasing due to environmental regulations and the phase-out of PFAS-based refrigerants. While these substances offer environmental benefits, they introduce new safety challenges related to potential leaks of CO₂ or propane into vehicle cabins or confined parking spaces, which demand real-time detection by advanced gas sensors.

CO₂ (R744) leakage risks

CO₂ is a non-flammable gas; however, its accumulation in enclosed spaces can pose serious health risks. In the event of a system leak, CO₂ concentrations can rise rapidly, leading to symptoms ranging from headaches and dizziness to unconsciousness at high levels. Standard vehicle HVAC systems may not detect such leaks promptly, especially if the leak is gradual and the system compensates for the loss without triggering alarms.

Propane (R290) leakage risks

Propane is a highly flammable hydrocarbon used in some refrigeration systems. Leaks can result in the accumulation of explosive gas mixtures within the vehicle cabin or on a garage floor, posing significant fire and explosion hazards. Even small leaks can reach dangerous concentrations, especially in poorly ventilated areas.

Safety through real-time leak detection

To address these risks, advanced sensors have been developed to provide real-time detection and alert systems. The integration of such sensors into vehicle HVAC systems enables continuous monitoring of cabin air quality, ensuring that any leaks are promptly identified and addressed. This proactive approach not only enhances passenger safety by preventing exposure to harmful gas concentrations but also ensures compliance with environmental and safety regulations.

Choosing the right gas sensor for your application

A variety of sensor technologies are available to meet the specific demands of automotive applications. Each comes with its own advantages and trade-offs in terms of accuracy, response time, and energy efficiency, making it essential to select the appropriate solution based on the requirements of the application.

Non-Dispersive Infrared (NDIR)
NDIR sensors operate by measuring the absorption of infrared light at specific wavelengths corresponding to the target gas. They are known for their high sensitivity, selectivity, and long-term stability. However, they can be sensitive to mechanical stress, which may affect their performance in automotive applications.
Photoacoustic Spectroscopy (PA)
PA sensors detect gases by measuring pressure waves generated when gas molecules absorb modulated infrared light. They offer high accuracy, selectivity, and low drift, making them suitable for continuous monitoring applications. They have been successfully implemented in various industries, including automotive, for detecting gases such as CO₂, methane, and propane.
Thermal Conductivity (TC)
TC sensors operate by measuring changes in thermal conductivity caused by the presence of a target gas. They are simple, scalable, and offer fast response times, making them suitable for leak detection applications. However, they cannot provide the same level of accuracy and selectivity.

Our solution

The SACD sensor module combines innovation, precision, and efficiency in one compact solution. Using advanced photoacoustic technology, it ensures reliable detection of CO₂ or propane leaks. Its compact design allows seamless integration, while support for LIN and always-on 12V systems, including bus wakeup capability, simplify implementation. With low-power operation and customizable alert thresholds, the SACD enables continuous, energy-efficient safety monitoring tailored to automotive needs.

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