Indicating Amplifiers - Indicating Amplifiers - Combustion Measurement

Measure & Control

Indicating Amplifiers

Modular amplifiers for high-end conditioning of cylinder pressure, manifold pressure, rail pressure, or timing signals for the purpose of combustion analysis.

AVL Approach

Our indicating amplifiers portfolio is suitable for most application fields and test environments. The different form factors of the FI/FlexIFEM and MicroIFEM amplifier families cover stand-alone usage as well as full integration into the test facility.

Benefits at a Glance

Quick sensor swap and best traceability due to AVL Sensor Data Management SDM^TM
Easy integration in various environments due to robustness and signal filtering
Compatibility with a large range of sensor types
High transient accuracy due to intelligent drift compensation for piezoelectric sensors
User-friendly parameterization due to full integration in IndiCom

Technical Data

Indicating amplifiers and signal conditioning

Product Family	MicroIFEM	FI	FlexIFEM
Number of channels	2 or 4	1 or 2	1 or 2
Power supply	9.5…36 VDC	9.5…36 VDC	9.5…36 VDC
Dimensions WxHxD	4.75'' or 9.5'' x 1HU x 230 mm	86x112x270 mm	86x112x270 mm
Weight	0.75 or 1.5 kg	1.6 kg	1.6 kg
Signal output	-11…+11 V	-11…+11 V	-11…+11 V
Parameterization	Remote via RS232 interface	Via front-keypad, or remote via RS232 or USB interface	Via front-keypad, or remote via RS232 or USB interface
Integrated LCD	no	yes	yes
Sensor Data Management	SID & SDC	SID(*) & SDC	SID(*) & SDC
Peak firing pressure measurement	yes (optional, only for MicroIFEM 2P5)	yes (optional)	yes (optional)
Additional time-based measurements	Engine speed for MicroIFEM 2P5	Engine speed	Engine speed Combustion noise Knock peaks

AVL Products

Indicating amplifiers

The AVL indicating amplifiers close the gap perfectly between our sensor solutions and our data acquisition units. Our amplifiers indeed offer full compatibility with our sensors, especially via our Sensor Data Management SDM^TM concept. The integration of our amplifiers in the indicating chain – especially in terms of parameterization and user-friendliness - is guaranteed by the software solution IndiCom.

Our amplifiers also offer complete stand-alone solutions in terms of basic combustion analysis, and their flexibility furthermore allows integration into a broad variety of testing environments.

Product Family	Description	Applications	Products
MICROIFEM	Well-proven, modular and advanced amplifier concept, best suited for applications directly at the test bed and in vehicle	R&D and application of light/heavy-duty, racing, large engines	MicroIFEM Piezo MicroIFEM Combi MicroIFEM Multipurpose
FI	Stand-alone and intelligent amplifier concept, furthermore delivering basic combustion characteristics such as peak firing pressure	R&D and application for light/heavy-duty, racing, large engines Endurance testing On-board measurement In-vehicle performance testing	FI Piezo
FLEXIFEM	High-end scalable amplifier family with increased processor performance for complex cylinder pressure-based computations such as combustion noise or knock peaks, upwards compatible to FlexIFEM Indi via simple software upgrade	R&D and application for light/heavy-duty, racing, large engines Endurance testing On-board measurement In-vehicle performance testing Acoustics development	FlexIFEM Noise, FlexIFEM Knock

Key Features

Key features	Description
Drift compensation	State-of-the-art drift compensation for highest accuracy Standard piezoelectric amplifiers are subject to drift, meaning that at constant cylinder pressure the output voltage signal does not remain constant as one would expect, but drifts towards either end of the output range. Such electric drift can have different root causes (e.g. low input isolation) and is inherent to the piezoelectric measurement chain, but can be compensated for so that the amplifier delivers a constant voltage at constant cylinder pressure. All our indicating amplifiers are therefore equipped with a state-of-the-art drift compensation technology, implemented by feeding back to the input of the operation amplifier a compensation current which is as large as the lost current. The feedback current is updated at the beginning of every cycle, thus ensuring highest accuracy throughout the entire measurement.
Peak firing pressure measurement	More than just an amplifier. Via built-in digitalization of the cylinder pressure signal and LCD display the AVL FI Piezo and FlexIFEM amplifiers optionally offer the possibility to detect engine cycles, display cycle-based pressure curves, and calculate peak firing pressure or engine speed. DAC and digital outputs transform those devices into real stand-alone p_max measurement or monitoring devices. Further time-based algorithms such as combustion noise are also available in the FlexIFEM family.
SDM Sensor Data Management	Increasing efficiency due to organized workflow SDM guarantees end-to-end automated data transfer and thus ensures error free measurements. This solution covers the complete measurement chain running from the sensor to the post-processing software. AVL Sensor Data Management™ SDM consists of several hardware and software components: SID Sensor Identification SIC Sensor Identification Cable SDC Sensor Data Connector SDB Sensor Data Base