Powertrain with IC Engine ApplicationThe development goals are as follows:
 | Assuring durability and wear-resistance of the entire powertrain | | Fatigue limit and durability testing for prototype release | | Basic optimization of control units |
The following development tasks are carried out on the test bed:
| Fatigue limit tests | | Testing of all powertrain systems | | Function tests on gearbox | | Loading of prime mover elements as in the vehicle to reach series release stage |
The AVL SolutionThe AVL Powertrain Test Bed with IC engine is a special test bed solution that focuses on the durability of the various components in the overall powertrain. The fatigue limit testing and basic optimization of the control units carried out on it can significantly shorten the series release phase.
The unique electric ground simulation makes the mechanical configuration simple and open for future extensions.
Five Reasons for Choosing AVL | 1.) AVL is the only supplier that can deliver a full chain of products for gearbox development with inhouse standardization. | | 2.) AVL provides a rounded, optimized total system from control to data acquisition and evaluation. | | 3.) AVL is the only supplier of powertrain test beds with decades of experience in state-of-the-art, proven electric ground simulation which it has always continued to develop. | | 4.) AVL has opted for a highly compact test bed design thus producing space-saving systems that are in demand today. | | 5.) AVL integrates feedback control in the automation so that the test beds are less prone to failure and can produce reproducible and repeatable results. |
Technical Highlights
Mechanical ComponentsThe test bed's mechanical configuration has to be tuned to the highly specific requirements of a powertrain test bed, such as different track width settings, for example. That means that dynamometers have to be adjustable. The AVL solution allows simple track adjustment by manual (or as an option automatic) shifting of the DynoTrain machines.
All the other modular mechanical standard components are specified to the requirements of powertrain testing and comprehensively tried and tested.
The special mechanical configuration of the Powertrain Test Bed is modular and open for future extensions.
The flexible mechanical configuration of the AVL solution gives users a test bed with multi-configuration capability. The Powertrain Test Bed can easily be reconfigured for testing vehicles with front and rear-wheel drive. Different tests can therefore be carried out on the same test bed which makes for enormous cost savings.
The versatility of the test bed with its multi-configuration capability guarantees operators higher productivity, saving time and money.
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AVL Dynolution – AVL DynoTrainA Powertrain Test Bed has to be suitable for dynamic simulation of driver, vehicle and track.
AVL has focused on electric ground simulation which gives the mechanical configuration of the test bed significant benefits.
Road resistance, vehicle mass and road gradient are easily simulated using the proven AVL DynoTrain and fast converter control with superimposed feedback control system with digital interface.
AVL DynoTrain consists of three-phase AC motors and appropriate converters specially developed for use on transmission and powertrain test beds. All the components of the modular system are combinable which guarantees maximum flexibility for adapting the system to special requirements and therefore the best possible safeguard for your investment The AVL DynoTrain is ideally suited to the development and testing of powertrains and the development and testing of transmission and drivetrain systems for front-wheel, rear-wheel and four-wheel drive vehicles.
The vehicle, road and driver simulation uses selected AVL dynamometers and digital control integrated in the automation system.
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Online Simulation: AVL ISACWhen working on the test bed, all the missing hardware has to be replaced by simulation models. AVL ISAC can simulate the vehicle, road and driver with its unique realtime models.
| Vehicle: apart from the dynamic properties, e.g. acceleration in the longitudinal direction, quasi-steady-state vehicle resistances are also simulated, such as wind resistance and road resistance. The electric ground simulation makes it possible to predefine the setpoints independently of the unit under test so there is no need for test unit-dependent calculation of the collective load (speed/torque). | | Track: in tests with vehicle simulation, predefinition of the track topology is mandatory. Input parameters for the driver and vehicle simulation model are the target values, e.g. track gradient, bend radiuses, maximum speed and desired speed. The Track and Drive Editor is used for the track description which saves time when creating the test run. | | Driver: the Driver simulation model assumes the tasks of acceleration, braking, speed control, as in a real vehicle. |
The development goals cited above can easily be achieved with these unique simulation models because the AVL solution makes the following actions possible:
| Realistic simulation of driveaway characteristics | | Both requirements are met by the Vehicle and Tire simulation models. | | Realistic simulation of the natural resonance characteristics | | The mechanical design and the right simulation make it possible to map the natural resonance characteristics. | | Realistic simulation of gear shifts |
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The EMCON 400 Series controller is very robust and guarantees reproducible and repeatable results. As a digital controller it is insensitive to interference and freely configurable making it easily adjustable to any test unit.
The control function is fully integrated in the automation system, i.e. various measurement quantities only have to be measured once. That minimizes cabling and reduces error sources.
Mechanics, dynamometer, simulation software and closed-loop control together produce a unique simulation environment for transmission/powertrain testing
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Automation90% of powertrain test beds are used for endurance testing to uncover any potential for optimization. The automation system plays an important role there. Fast setpoint definition (at 500 Hz) is required for replication tests to be able to handle high-frequency processes (e.g. gear shifts) easily.
Also more measurement points have to be taken into account than on the engine test bed (approx. 20-30 pressures for automatic transmissions). A sampling rate of at least 1 kHz is required. The special Automation for Powertrain Testing allows a sum sampling rate of at least 50 kHz and meets those tough requirements.
One basic difference from an engine test bed is that there are no mandatory statutory cycles. All users define their own setpoint profiles which when it comes to the automation means that the cycles have to be easy to parametrize. The AVL library concept also ensures that they are easy to manage and can be extended as required.
The realtime recorder with a band width of 25,000 values/sec can record all the relevant quantities during a test run and runs absolutely in sync with the automation and control systems.
The acquired data is evaluated for powertrain testing on the basis of integral criteria. For example, the classification (rev count or rainflow classification) plays a significant role in fatigue limit evaluation. This methodology requires incredible amounts of data that have to be reduced to a sensible minimum volume. AVL Magic is just the tool for the job as it provides impressive methods for data reduction and post-processing.
The gearshift evaluation method developed by AVL is also based on a sensible data reduction method. Characteristic data is determined for gearshift processes to allow early detection and optimization of changes in the gearbox.
The very large amounts of data are acquired and evaluated sensibly with the development goal in mind.
Fast limit value monitoring with minimum response times is necessary for the safe operation of the test bed and the safety of the operator. That is handled by the AVL ARTE realtime operating system which (dynamically) monitors a reference cycle and is able to check an instantaneous measurement quantity against a setpoint.
Immediate, parametrizable response when a limit value is exceeded.
Numerous interfaces, such as COM via VB Scripting, CAN, Profibus, FireWire, CDH make it easy to integrate separate software functions, a wide range of measuring equipment and the ECU/TCU.
AVL thus supports customers' enthusiasm for experimentation as well as supplier independence.
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Measurement TechnologyFor injection systems with vapor bubbles in the return line, AVL recommends the tried and much tested AVL 734 Double Fuel Balance and associated conditioning unit for powertrain test beds. The Balance offers exceptionally high accuracy (0.12% measurement accuracy) and the special conditioning system is designed for consumptions of up to 360 kg/hr and can condition the fuel to temperatures from 0 to 60 deg. C to within 0.5 deg. C. Stable temperatures are a must in order to achieve reproducible results.
Alternatively, AVL can also recommend the AVL Fuel Mass Flow Meter in conjunction with the AVL Temperature Control. The improved Mass Flow Meter is extremely reliable in test bed operations and easy to use with new mixture preparation systems, such as direct injection systems in gasoline and diesel engines. Quick and easy to integrate in the test bed environment, it minimizes downtimes while the graphic user interface makes it highly user-friendly.
AVL can also quote for special oil and water conditioning units to customer specifications on request.
The special instrumentation recommended by AVL for the specific test bed application of Advanced Powertrain Testing means that the test bed can easily be extended to handle future changes.
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