AVL FuelExact™ Mass Flow & PLU

The FuelExact is a high precision fuel consumption measurement system. It ensures higher testbed efficiency by determining fuel consumption with the highest precision and minimum measurement time.

AVL Approach

The application covers the range from single-cylinder up to 2500kW. Highest fuel temperature stability and cooling power fulfill all current requirements linked to transient and dynamic testing.

Benefits at a Glance

  • High flexibility for adaptation to different injection systems as well as a wide range of engine power up to 2500kW
  • Highly efficient on the test bed due to unique repeatability and reproducibility of measurements values with minimum measurement time
  • Easy service due to a large number of diagnostic functions as well as easily accessible hardware components
  • Minimized commissioning effort via standardized interfaces and diagnosis functions
  • System calibration according to ISO, UN ECE R49 & US EPA Part 1065 via AVL Fuel Reference
  • Not influenced by pressure surges caused by the injection system

Technical Data

AVL FuelExact™ PLU Fuel Consumption Measurement System

Technical Details AVL FuelExactTM
Type: AVL 740
Measurement principle: PLU or mass flow

Measurement ranges:

Mass Flow

0.03 … 500 l/h*)

0 ... 500 kg/h *)

Systematic Measurement




<=0.1 % (acc. to DIN 1319)

1 g / dm3

Interfaces / output signal: Ethernet, RS232
Analog I/O 0 ... 10 V
Digital I/O
Fuels: standard **) and 100% bio fuels
Fuel feed pressure: 0.1 ... 10 bar (Vacuum optional)
Fuel return pressure: 0.1 ... 2 bar (Vacuum optional)
Fuel circulation rate: up to 840 l/h (up to 2400 l/h using a external heat exchanger
Fuel conditioning:  
Control range: 10 … 80° C (-10° C Optional)
Stability: better than 0.02° C
Heating / cooling: 3 kW / 6 kW
Power supply: 3 x 400 V AC, 50 - 60 Hz
Ambient temperature: +5 ... +50 °C
Dimensions (W x H x D): 960 x 1,710 x 430 mm
Weight: ~ 300 kg

*) With different sensors
**) With max. 20% alcohol and up to 10% bio diesel
***) 0,1 … 0,5 bar for FuelExcat Mass Flow

Measuring Principle

PLU Measurement Principle
The PLU positive displacement meter combines a servo-controlled gear counter with a dynamic piston sensor. A gear meter (2) driven by a servo motor (7) with encoder (8) defines a geometric volume to pulse frequency ratio when gear rotation is adjusted to media flow. A bypass (5) ensures zero pressure difference (∆p=0) between inlet and outlet, preventing leakage flow. Flow changes immediately displace a zero-friction piston (4) in either direction. A piston position sensor (3) and a servo controller (9) provide a fast gear speed control loop keeping the piston centered.


Mass Flow Measurement Principle
Fuel passes through a U-shaped tube, which vibrates at its natural frequency. This frequency is proportional to the fuel density, which in addition to the mass flow is a separate measurement variable and thus allows for the output of volumetric measurement values. The time lag of the vibration frequency C1 to C2 is proportional to the mass flow.