Novel Flywheel Torque Sensor for the Optimization of Truck Drive Trains based on Sensor Telemetry

MANNER: Emission standard Euro 4 has now reached trucks. Providing an optimal match between engine and transmission is of particular importance for CO2 emissions and fuel consumption data. For this purpose, appropriate measuring instruments are required. An essential factor is the dynamic torque curve between engine and transmission. CAN data alone neither provides a sufficiently accurate calculated torque value, nor permitting dynamics-related corrections. The integration of a standard transducer requires an extension of the drive train which can affect its dynamic properties. A standard transducer will have difficulties dealing with the environmental conditions during real driving (temperatures up to 140°C, vibrations and oil). A desirable solution is to install a high-precision mechanical torque measuring device into the drive train without changing its stiffness and without additional space requirements. Due to the limited changes possible, the only way is to convert the production flywheel to act as a torque sensor.

MANNER has developed a process which converts the actual flywheel into a high-precision dynamic torque transducer. It is characterized by its consistent high accuracy of 0.1% over a temperature range of -40 to +140°C. This is achieved through compensation of the temperature-dependent change of the modulus of elasticity and zero point drift compensation. For this purpose, part of the flywheel is replaced by a purpose-built component. Its design is specifically developed to avoid torque distortion due to parasitic forces such as axial thrust, centrifugal forces, and bending moments. The measuring device can be used for both in vehicle and test bench operation.

These measuring devices have been used for many years in the automotive sector with great success and are now also available for trucks. The measured dynamic torque data of a strain-gauge based transducer are transmitted in a non-contact mode through the tried and tested 16 bit resolution digital sensor telemetry technology from MANNER. Special features include the high temperature resistance of up to 160°C and the high operational stability during driving. The measured data can be passed to the data acquisition system as a classic analogue signal with 0 to ±10 V or as a digital signal via the CAN interface.

Bearingless Torque Measuring Shaft for Test Applications has many Advantages over Classic Torque Measuring Shafts

The classic torque measuring shaft for test bench measurements has many drawbacks compared to bearingless measuring shafts. A traditional measuring shaft is typically mounted on bearing trunnions and may even comprise of slip rings. The required bearing brings with it wear and tear as well as a force shunt. It also requires a bearing bracket and elastic couplings. These are some of the reasons why the mounted measuring shaft has completely disappeared from car test laboratories.

MANNER Sensortelemetrie offers bearingless torque measuring shafts. This solution is an overall cheaper alternative, since couplings and bracket are not required, and more compact options are feasible. When it comes to accuracy, in particular, the bearingless shaft shows clear advantages. The basic accuracy of MANNER measuring shafts is better than 0.05%, which would not be achievable with a measuring shaft mounted in a bearing housing.

Couplings and bearings are problematic at high speeds. The selection of a suitable coupling while taking into account the shaft dynamics requires special knowledge. Shaft vibrations due to incorrect couplings have caused heartache to many a test rig engineer. The MANNER bearingless measuring shaft can be used at up to 150,000 rpm.

MANNER Sensortelemetrie has developed special compact bearingless torque sensors of 1Nm to 1kNm range for test rig applications. Characteristics include an extremely low moment of inertia, high-speed performance and easy integration into the shaft train. Affordable Lenze clamping elements are used for the connection with the shaft train. All torque detection systems by MANNER Sensortelemetrie feature non-contact transmission of the torque signal using the MANNER patented process of sensor telemetry.
The torque signal is obtained through strain gauges. A high-precision, remotely programmable instrumentation amplifier in the shaft amplifies, conditions and digitizes the measured value with 16 bit resolution. The contact-free transmission features an air gap of up to 10 mm for easy assembly both in radial and axial directions. The torque data can be outputted as analogue or digital signals via CAN, EtherCAT, Ethernet or USB. MANNER Sensortelemetrie's engineering department is happy to advise you and manufacture customized torque sensors to meet individual customer's needs.

Advanced Sensor Telemetry with Auto tuning Performs High quality Dynamic Torque Measurements on the Powertrain

In order to optimize a vehicle's powertrain, it is imperative to measure the dynamic torque on the drive train during every type of maneuver. Such measurement is today indispensable for tuning the vehicle and optimising powertrain efficiency, as it increases both driving comfort and operational stability. When developing new vehicles an optimised drive train is a significant competitive advantage.

The dynamic torque in the half shafts is now commonly determined using strain gauges and by transmitting measured signals using near-field telemetry systems.
Given increasingly confined spaces and the large transverse half shaft movements, in particular at the front, the requirements on transmission technology are enormous.
MANNER has met these demands with an advancement in sensor telemetry. The innovation is an auto-synchronising stator antenna in the form of a flexible loop that can be formed to the vehicle body shape. The distinctive feature of the newly patented method is the self-synchronising loop antenna which automatically optimises the power transmission. This guarantees a plug and play solution for virtually any installation situation. It is simply placed around the rotating shaft and fastened to the vehicle body. Integrated shielding makes any contact with body parts inconsequential. This solution tolerates variable distances of 0 to 100 mm between the stator antenna and half shaft. It is characterized by absolutely reliable transmission even on extremely rough terrain or in harsh environment based on the digital transmission technology.
Combined with MANNER Flex technology, solutions can be found for the smallest clearances between drive shaft and vehicle body. The measuring range settings and auto-zero function can be remotely controlled over the telemetry link (RMC technology).

Dependable digital sensor telemetry technology from MANNER with 16 bit resolution ensures highest resolution and accuracy at temperatures down to -50 °Celsius. The industry standard CANBus interface allows straightforward integration into data capture networks.