Measuring Vehicle Efficiency and Power Mapping

Powertrain efficiency is determined by how power is transmitted, transformed, and lost as it moves from the power source to the road. Quantifying those losses requires torque and speed measurements at multiple locations, captured under real operating conditions and correlated across the system.

Michigan Scientific supports powertrain efficiency testing by engineering integrated measurement systems spanning engines or motors, transmissions, driveline components, and wheel ends.

Engine Output Transducers

Measuring engine or motor output establishes the baseline for all downstream efficiency analysis.

Commonly instrumented components include:

• Crankshafts
• Flexplates (automatic transmissions)
• Flywheels (manual transmissions)

Transducers can be made from, or applied to, internal production components, including direct strain‑gauge application that transforms the component itself into a precision torque transducer while preserving its mechanical behavior. Measurements can be transmitted using instrument-quality slip rings or wireless telemetry, depending on packaging and test constraints.

Engine output measurements allow engineers to:

• Quantify mechanical output under real operating conditions
• Separate internal losses from downstream drivetrain losses

Transmission Driveshaft Instrumentation

Transmission efficiency is determined by correlating input and output torque across operating conditions.

Transmission output torque is commonly measured using:

• An instrumented transmission output shaft
• An instrumented driveshaft

Instrumentation and data transmission:

• Transmission output shafts or driveshafts are instrumented using strain gauges
• Internal wiring for protection and signal integrity
• Data transmitted via slip rings or wireless telemetry (inductive or battery powered)
  • The choice between slip rings and telemetry is typically driven by packaging constrains, operating speed, environment, and test duration.

Common sources of transmission losses include:

• Torque converter efficiency
• Oil pumping and heat losses
• Viscous spin losses
• Gear, bearing, and seal losses

Driveshaft and Axle Measurements

Downstream of the transmission, torque measurements on driveshafts and axles allow engineers to:

• Quantify losses between the transmission and wheel ends
• Validate drivetrain models and simulations

Michigan Scientific frequently applies strain gauges directly to production driveshafts and axles, integrating mechanical adapters, protective housings, and rotating signal transmission to create durable, test‑ready measurement systems.

 

Closing the loop at the Wheel End

Wheel torque and wheel force measurements provide the final output of the powertrain, capturing how much usable power is delivered to the ground. When combined with upstream torque measurements, wheel‑end data allows engineers to quantify total drivetrain losses and correlate efficiency across the entire powertrain.

While many factors influence vehicle efficiency, understanding power losses within the driveline remains a critical part of vehicle design and development.

To learn more about how Michigan Scientific can help with vehicle development, contact an MSC engineer.