Manufacturers in automotive and aerospace engineering use internal combustion engines to drive an aircraft or vehicle. These engines are tested and verified for optimal performance and quality before they are integrated into an automobile. This process includes verifying the numerous pressure sensors inside these engines that measure fluid pressure at critical points in the engine.
Engine Calibration
The operation of a modern internal combustion engine is typically governed by an Engine Control Unit (ECU). This computer receives numerous inputs from various sensors so that it may provide outputs to control the operation of the engine. An engine calibration is performed by using numerous different sensor outputs that provide the variables required to efficiently operate the engine.
In order to produce the engine calibration, it must be run in an engine test cell. This is a controlled environment where a load can be applied to an engine and its vitals can be monitored by various different types of instrumentation.
Engine Test Cell
An engine test cell typically includes, but is not limited to, a dynamometer, ventilation system, cooling system for the engine and dynamometer, fuel system, exhaust system and various types of instrumentation and data acquisition systems to monitor the operational characteristics of the engine. It is beneficial to have very precise and accurate temperature and pressure measurements so that adjustments to the engine will result in the desired outcome.
Of all the data gathered during engine testing, Mensor transducers can be used to obtain pressure data for:
- Barometric Pressure (pressure inside the test cell)
- Compressor Inlet Pressure (pressure drop across the air cleaner, pressure going into the turbocharger)
- Compressor Discharge Pressure (pressure output from turbocharger)
- Manifold Absolute Pressure (pressure between the throttle and the intake valve)
- Turbine Inlet Pressure (pressure between exhaust valve and turbine inlet)
- Turbine Discharge Pressure (pressure between turbine and exhaust catalyst)
- Exhaust Back Pressure (pressure between exhaust catalyst and muffler)
Typical Installation
Engine test cells come in many shapes and sizes. This is because of how the test cell is normally setup for the engine and the type of work that is being performed. However, it is common to see many of the temperature and pressure measurements brought back to a central area where the data acquisition system receives the signals. Many of these data acquisition systems are composed of enclosures that contain pressure sensors and thermocouple input modules.
The pressure sensors manufactured by Mensor are ideally suited for this type of application because of the small form factor, RS-232/485 communication and accuracy.
Modular Installation
One technique is to install a set of pressure transducers into an enclosure that is capable of powering the instruments and integrating them into the existing data acquisition system. This modular design is advantageous because it allows the instrumentation to be swapped out and calibrated as needed. It also allows for the pressure sensor arrangement to be setup and run on a bench without taking down a data acquisition system in a test cell.
Conclusion
Engine test cells utilize a variety of sensors to ensure quality and to document adherence to specifications. The Mensor CPT6030 with 4-20 mA output and the CPT6020 or CPT9000 with digital outputs provide high accuracy, reliable, compact solutions for pressure measurement in these critical testing environments.
Related Reading:
- Pressure Transducer Applications in Oil and Gas Exploration
- Pressure Transducer Applications in International Arctic Buoy Program
- Pressure Transducer Application for Rocket Engine Testing
- Flow Meters that Use Pressure Sensors to Derive Measurement
- How to Choose a Pressure Transducer: Ten Things to Consider
- Comparing Different Types of Analog Pressure Transducers
