RT final stage prototype testing: big strides towards series production

Preparations

RT Berlin with built-in monitoring and measurement system

Testing of the RT vehicles began at the beginning of July, in order to get the pre-series vehicles ready for use by our customers.

For this purpose, a comprehensive monitoring and measuring system was installed in every vehicle. This records the CAN signals from various systems for every activity of the vehicle (such as speed, engine rpm, battery charge status, coolant temperatures, and other metrics). In addition, various sensors record acceleration, pressure, temperature, or the flow rate in various scenarios. An accurate GPS signal and the recordings from the dashboard camera also assist in the evaluation of the measurement data in order to allow a deeper analysis of the vehicle’s behavior. In addition, strain gages affixed to the relevant components can be used to determine the loads that occur, facilitating their optimization accordingly.

And the vehicles were not only packed full of electronics: additional weights were also installed for the driving tests to simulate the vehicle’s payload. Therefore, the equipment compartments were loaded with filled water tanks. The crew cabin seats were filled with “dummies” in the form of simulated, water-filled upper bodies made of plastic. Of course, the superstructure’s water tank was also filled, as this acts as an essential component of the vehicle’s weight balance.

The vehicles were then tested on the in-house brake test bench and the steering geometry, alignment, and headlights were fine-tuned. It was then given a cold shower (leak test with the spray beam) before heading on to the next phase.

Tests on the testing ground

MAGNA testing track in St. Valentin, Austria (©ENGINEERING CENTER STEYR GmbH & Co KG)

The first dynamic vehicle tests were carried out at the MAGNA test track in St. Valentin (Upper Austria), with the vehicles being put through their paces in terms of acceleration, braking, cornering, lane changes, etc.

The new special features of this vehicle type, e.g., the rear-axle steering and the height-adjustable chassis, were also put into operation, with the maneuverability and off-road capabilities also being analyzed and evaluated.

The driving dynamics and the steering system were then evaluated in a 100 km endurance run, and the entire system was operated into a “stable” condition. In addition, all relevant connections were checked in a daily routine during the testing phase.

This was followed by the parameterization of the automatic differential lock function, so that off-road terrain and 40 % inclines no longer posed a problem.

Then another 300 km endurance run (on asphalt and unpaved ground) was performed before the next stage of testing.

RT Berlin during a test drive through the railway station district in Linz

Tests on the road

Equipped with prototype number plates, the RT can also be driven on public roads and, with its unusual sticker cladding, attracted a great deal of attention from passers-by.

The test drivers were particularly impressed by the driving performance and the good maneuverability of the vehicle when it was put through its paces in the central Linz area. The electric drive enables the vehicle to accelerate quickly and without interruption, and when slowing down the braking energy is converted into electrical energy by means of recuperation. In hybrid mode, the range extender (diesel engine) ensures that the deployment range and duration are extended accordingly.

Tests at Rosenbauer

RT prototype 1 during the pump functionality test

Emergency vehicles are not only driven to the scene of an emergency, but also actively operated once they arrive. That meant that all equipment necessary for a successful operation must also be tested during the test phase.

The most important aspect of this is the pump test bench. The extinguishing water pump integrated into the vehicle is tested in conjunction with the piping. In addition to its maximum performance, the pressures and flow at certain required operating parameters were also determined.

In addition, the electrical components, such as the warning devices (blue light and siren), the LED scene lighting and the optional power supply, which converts electrical energy from the high-voltage battery and makes it available to the use of external electric devices, are checked for their functionality.

Another major innovation in this electric vehicle is the charging capability (plug-in charging). After the many tests, the energy storage device (high-voltage battery) also had to be recharged, and this process also requires a few tests in which, among other things, the communication between the vehicle and the charger must be adjusted. The vehicles are fitted with a Combo CCS Type 2 charging connector, which allows charging in AC mode at up to 22 kW and in DC mode at up to 150 kW.

We’re not done yet

The testing phase for the first pre-series vehicles has not yet been completed, as tests and inspections will continue right up until delivery. In order to maintain an overview, a comprehensive test catalog was created, which every single vehicle will be subjected to. That starts with functional tests, followed by static and dynamic vehicle tests, certification tests, and finally vehicle acceptance by the customer. The vehicles are also extensively tested on the customer’s premises, and the crews are trained in how to operate them before the RTs are put into service, marking that moment, when outstanding technology is the critical factor.

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