AirSupply Smart has shown what it can do when it really counts – in daily operation on Tokyo Metro’s passenger service. The high-frequency service is exceptionally demanding, with short dwell times, frequently changing loads, and hugely fluctuating compressed-air requirements.
The results of the field trial speak for themselves: Operator Tokyo Metro Co., Ltd gave AirSupply Smart’s performance a very positive rating and formally approved the system for operational use – an important milestone for future projects in Japan. Philipp Verheyen, Product Manager for AirSupply Smart, summarizes the outcome: “Tokyo Metro’s operations are extremely demanding, and AirSupply Smart provided impressive proof that it is capable of delivering the highest levels of performance and reliability even in very challenging conditions.”
The Knorr-Bremse Sakado Service Center, located close to the capital, played a key role in the project’s success. Its engineers supported the project on-site from the very beginning, training Tokyo Metro staff in data retrieval procedures, carrying out incoming inspections of AirSupply Smart units, and performing regular disassembly inspections throughout the trial period at the operator’s site.
Seamless integration with vehicle design
Vehicle integration was another area where AirSupply Smart excelled. Seamlessly integrated into the existing system, the unit’s efficient communication with the vehicle ensured that exchanges of signals, feedback and diagnostic data did not disrupt higher-level control logic. At the same time, the unit’s pneumatic and electrical interfaces were optimized to ensure that the solution perfectly matched the vehicle design. For operators and vehicle manufacturers, AirSupply Smart guarantees high-level system compatibility, problem-free integration, and efficient operation in existing fleet environments.
Soft Start reduces peak loads in the onboard power supply
One of the key factors behind the success of this project was the Soft Start function built into AirSupply Smart. Soft Start ensures that the compressor starts up very smoothly, significantly reducing peak currents in the onboard power supply. “We use the inverter with voltage-frequency characteristic curve control for a smooth compressor start-up,” explains Verheyen. “This helps to substantially reduce power-on currents.”
The practical relevance of this benefit is illustrated by the design of Tokyo Metro’s 13000 Series vehicles. Here, compressed air is usually generated by four smaller compressors, which the vehicle control system powers up in a staggered sequence to avoid peak loads. AirSupply Smart uses the more powerful PistonSupply Eco VV180-T compressor, but the Soft Start function limits the amplitude of the power-on current to match the nominal current, so it is even lower than it would be if the system still used smaller compressors starting at staggered intervals. This has major advantages for the vehicle’s power supply – and creates additional technical headroom for vehicle designers.
A strong reference for the Japanese marketplace
Throughout the field trial, the integrated data logger continuously recorded important operating data such as load profiles, switching cycles, and thermal conditions. Thanks to this comprehensive information, tracking of the system’s real-world operating behavior was completely transparent, demonstrating the potential of Knorr-Bremse’s integrated Condition Monitoring approach in everyday operation.
Tokyo Metro’s approval of the system provides Knorr-Bremse with vital proof of AirSupply Smart’s suitability for the Japanese market. Not only will this allow Knorr-Bremse to take part in future Tokyo Metro tenders – it also provides a strong reference for future projects, whether in Japan or in other international applications.