Froude Hofmann benefits from many generations of knowledge and experience, and provides a comprehensive product portfolio in all application of engine and vehicle testing. Covering the R&D and full production environments, Froude Hofmann is able to understand the customer’s needs, and use this cross-functional knowledge to provide innovative test solutions. These solutions enable testing to be performed accurately and reliably, from an early stage of an engine’s development cycle, through to full vehicle testing and production validation and quality assessment. This involvement ensures a detailed view of market demands and trends that drive forward thinking and product development initiatives.
Focused research activities, along with a structured development process control, include prototype build and extensive testing, which ensure required innovations are brought quickly to the customer.
The latest generation of 48in chassis dynamometers builds on company successes in exhaust emission, endurance, climatic and NVH test applications. The latest design techniques have been used to create a modular system that incorporates a high degree of pre-engineering to produce a flexible configuration. This realizes various customer benefits, such as a configurable design for 4x2, 4x4 and 4x4 independent designs, shorter delivery times and reduced installation and commissioning times.
The chassis dynamometer control system uses advanced algorithm designs and control techniques to provide a responsive, dynamic and accurate control of the forces and speeds under all operating conditions. This setup ensures the road load and inertia simulation is precise and accurate, helping the vehicle experience the correct forces under dynamic test conditions. This precision of control is applied to various chassis dynamometer configurations to ensure confidence in testing for either regulatory or vehicle and powertrain development activities.
A single-axle chassis dynamometer works with two rolls and a center-mounted AC machine. This accurate road load and inertia simulation exceeds the demands of the US EPA and worldwide regulatory requirements for vehicle exhaust emission testing. With the benefit of accurate road simulation, the vehicle can be tested in lab conditions under a variety of applications, including 4x2 vehicle regulatory exhaust emission testing, emission development testing, automated/endurance testing, durability and NVH.
The 4x4 chassis dynamometer is as above with the added flexibility of two center-mounted motor/rolls assemblies, four-wheel drive vehicles that can therefore also be tested under full road simulation.
To accurately simulate the on-road conditions, the 4x4 chassis dynamometer control system maintains the rolls at the same speed. This is achieved by ensuring that the sum of the forces applied to both the front and the rear axles correctly simulates the total vehicle inertia and road load force, while the actual forces applied individually to each axle by the AC motors are automatically and dynamically adjusted to ensure that the rollers run at the same speed. This movement of forces is highly responsive to the force distribution pro-duced by the vehicle between the axles, thus providing accurate roll speed synchronization and allowing the powertrain to operate as if driving on the road. This capability realizes further test benefits, such as all applications listed for the 4x2 chassis dynamometer; 4x2 or 4x4 vehicle testing; driveline testing; fully speed-synchronized rolls or variable force/speed distribution front to rear with the split defined as a percentage or absolute value.
The details above are relevant to the 4x4 (independent) chassis dynamometer, with the ultimate flexibility of four individual motor/roll assemblies, and all four wheels of the vehicle are under independent control. In normal operation all four rolls are accurately synchronized to present a through-the-road simulated condition to the test vehicle’s powertrain. This is achieved using the same control concepts of force distribution discussed above; with the additional demands of cross axle independence. With this added flexibility, further test applications are realized, including: all applications listed above (4x2/4x4 chassis dynamometer), complex driveline testing including hybrid configurations, corner simulation and ABS/TCS simulation test.
Texcel V12 is the latest version of the Froude Hofmann Texcel family of engine test control system. The TxV12 uses the latest-generation electronics, software and high-speed network techniques to provide a fully integrated engine/dynamometer and data acquisition system. This uses a number of distributed intelligent I/O hardware modules, called DX100s. These high-performance, multi-function I/O modules have the advantage of converting all analog signals to digital format in the testbed and sending data via a network link to the real-time processor (RTP) for viewing on the operator’s PC. This improves data accuracy by reducing signal noise and data through-put, and also greatly simplifies the testbed installation and commissioning.
The Texcel V12 can be configured for use in a wind variety of applications such as R&D, quality assurance and post overhaul testing. A number of features are available to enhance the standard functionality to enable legislative emissions testing to be performed together with ECU communications and an ECU optimization control interface. These passenger car and truck regulatory exhaust emission tests include USA federal test cycle FTP5; ECE-15+EUDC, EURO 3, 4 and 5.
In combination with a Froude Hofmann AC dynamometer, simulated in-vehicle testing of an engine reduces development time and provides correlation between data produced by a vehicle tested on a chassis dynamometer. Features include vehicle definition, including road load model, gearbox and clutch simulation; drive cycle definition, editing, storage and management; and data logging analysis.
The Texcel V12 has a number of options to extend its functionality, including high-capacity I/O by adding additional DX100 modules and dedicated emissions test software. Texcel V12 has been designed to provide ease of use in setting up tests and acquiring data. It can be used to ensure high-quality testing and high-integrity of test results. It can control AC, eddy current and hydraulic dynamometers, together with a range of engine throttle systems. This permits manual and automatic test systems to be run and data acquired. In addition, the sequencer controls logging, other PIDs, such as coolant and lube oil temperatures.
The user interface software runs on an industry-standard Windows XP PC and is configured using standard menus and forms, allowing the operator to quickly set up and define new tests. The user interface allows the operator to configure the instrumentation screens to meet any test requirements. This can be achieved using the screen layouts supplied or by quickly creating custom displays. All manual and automatic tests can be configured and run using keyboard and mouse. A manual control console is also provided that includes the throttle and dynamometer demands, reset and stop buttons.
The Texcel control system integrates all the equipment within the emission test cell to provide a unified control and data acquisition system for automatic emissions engine testing and reporting. Together with the normal engine parameters, the Texcel includes interfaces and controls for: engine lubrication oil and coolant conditioning systems, fuel consumption and conditioning systems, combustion air conditioning, charge air cooling, exhaust emission analysers, turbo charger intercooling and exhaust emission Analyser systems.
In the continuing demand for improved quality; the Vehicle manufacturer has to pay great attention to the final build quality. To provide effective tests in this demanding production environment; one of our latest Test Products is the shake roll test stand. This provides the ability to induce vibrations into the vehicle at the end of production, whilst the vehicle is driven at speeds of up to 50 km/h. The rig also consists of four individual motored rolls that can pivot +/- 5o to introduce bend and twist into the chassis. Each roll is fitted with variable pad heights to simulate amplitudes and road effects.