Endurance TestingThe aim of endurance (or durability) testing on the engine test bed is to ensure reliability of the engine throughout the lifetime of the vehicle by testing for certain failure modes. These include mechanical and thermal fatigue, wear, chemical corrosion and ambient-related failures, or combinations of these, such as liner cavitation or exhaust valve seat wear.
Durability tests are divided into failure-oriented tests and usage-oriented tests. Some examples of tests are:
- Rated power test
- Load cycle test
- Overload test
- Piston bowl crack test
- Thermal shock test
- Exhaust manifold crack test
- Water and gas side thermal shock test
- Cold start / part load test
- Resonance test
In addition there are certain endurance tests that have to be specially tailored, such as tests on the exhaust gas after-treatment system, the fuel injection system or on valve train components.
Demands on the Test BedFailure-oriented endurance testing such as load cycle or thermo-shock tests are usually carried out on a steady-state test bed, where a passive dynamometer can be used.
Usage-oriented tests, on the other hand, aim to simulate real usage conditions, such as city traffic or highway driving. On the engine test bed this calls for transient or dynamic testing, for which an asynchronous dynamometer is necessary, as well as the corresponding control system and simulation software. Conditions have to be achieved that are near the reality of the vehicle as possible. This may entail, for example, gearbox simulation or the usage of a gearbox dummy, or simulation of vibrational conditions. Both the dyno controller and the test bed mechanics must take these factors into consideration.
For test preparation the automation system must be programmed and optimised for the particular test. Alarm and shut-off limits have to be defined.
During testing, a whole range of pressures, temperatures and other parameters need to be taken.
Temperatures, e.g.:- Air-intake temperature
- Oil temperature in the main gallery and oil pan
- Coolant in and out temperature
- Exhaust gas temperature in the downpipe
- Individual exhaust temperatures for each cylinder
- Fuel temperature at injection pump inlet
Pressures, e.g.:- Ambient pressure
- Intake manifold pressure
- Oil pressure before oil filter and in main gallery
- Coolant in and out pressure
- Crankcase pressure
Other parameters, e.g.:- Engine speed
- Engine torque
- Ambient air humidity
- Exhaust gas air excess ration or air mass flow
- Blow by
- Fuel Flow
Increasingly, gaseous emissions also have to be measured to detect emissions deterioration – whether or not ageing of the engine affects the emissions levels.
The AVL SolutionAVL offers complete endurance test beds for all engine sizes, with particular emphasis on system stability for unmanned operation. AVL products are designed for fast and seamless integration, supported by the automation system PUMA Open, which acts as an integration platform.
Mechanical ComponentsAVL offers a wide range of mechanical equipment for test bed operation. Proven standard solutions cover many automotive applications. In addition AVL provides tailor-made systems.
Standard mechanical components for an endurance test bed are:
- AVL Cable Boom and Boom Box FEM or AVL Wallbox FEM
- AVL Drive Shaft System
- AVL Engine Mounting System
- AVL Intermediate Bearing (optional for long shafts)
- AVL Intermediate Frame
- AVL Isolated Base Plate
- AVL Pallet System
- AVL Shaft Guard
DynamometerFor failure-oriented, steady-state endurance testing AVL offers the DynoPerform range of eddy-current dynamometers, up to 500 kW.
For transient endurance testing the AVL DynoRoad AFA Series and the AVL DynoExact APA Series of dynamometers with foot-mounted design and dynamic vehicle simulation is suitable. This allows driver profiles to be run, as required for some endurance tests.
Product Description
Data Acquisition, Automation and ControlAVL's PUMA Open Automation System is offered in a configuration suitable for endurance testing. PUMA Open acts as an integration platform, integrating the various sub-systems into a functioning whole.
For dyno control AVL offers the BME 400. If the test requires the control of the engine – in the case of dynamic applications – AVL offers the EMCON 400 system, integrated within the automation system PUMA Open.
The proven AVL Front End Modules (FEMs) have been developed for data acquisition because they can be positioned in the cell, close to the unit under test, maximising signal quality.
Product Description
Actuators and SensorsThe following sensors can be provided as required:
- Ignition timing systems
- Temperature Sensors
- Air Mass Flow Meters
- Humidity measurement systems
Actuators are not usually required for endurance testing but can be provided if needed.
Product Description
Media Conditioning EquipmentAVL provides media conditioning equipment for the units under test and the media – coolant, oil, combustion air, fuel.
- AVL 553 Coolant Conditioning System
- AVL 554 Oil Conditioning System
- AVL Combustion Air Conditioning System
- AVL Dynamic Combustion Air Conditioning System
- AVL Fuel Temperature Control
- AVL Boost Air Conditioner
- AVL Exhaust Back Pressure Adjustment Kit
Operating Panels and CabinetsDepending on the available space and the test equipment required, AVL offers a range of easily adaptable modular system cabinets and operating consoles. Where only limited space is available, special compact solutions are available.
- AVL Test Commander Operating and Control Desk
- AVL Test System Operating and Control Cabinet
- AVL Test System Operating and Control Desk
- AVL Compact Cabinet – wall mounted 19" cabinet
- AVL Console for the operating panel AVL P400
Other InstrumentsServiceTo round off the AVL solution we offer a range of services to ensure reliability and availability of your AVL test cell.
- AVL eSpares online spare part procurement ensures rapid ordering and delivery of standard spare parts
- Hotline for fast and personal response to your queries
- Training, to ensure that you make the most of your AVL system
- Software Care Packages
- Full repair service
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