Challenge in the Arctic

Volvo Trucks North America (VTNA), the American branch of the Volvo Group, is continuing the brand's long tradition of subjecting its vehicles to validation tests in extreme weather conditions. This took place in Fairbanks, Alaska, where the new Class 8 heavy-duty trucks from the VNL range had to face the challenges of the far north, with temperatures as low as 40 degrees below zero, icy roads, snowstorms, freezing winds and overnight stops in the open with no shelter. All this was done to validate the performance and driving comfort expected in the design phase in the five different biomes that characterise North America, namely urban environments, desert areas, grasslands, coastal forests and the Arctic tundra. 

Real-world testing conducted (and passed) in these environmental conditions ensures that the vehicles are ready for coast-to-coast transport missions covering routes of over 3,000 miles. Professional drivers, many with decades of experience driving on Alaska's impossible terrain, provide detailed feedback to the Volvo Trucks North America test team on a daily basis. This information, combined with real-time truck performance data, helps specialists fine-tune every aspect of the vehicles, from powertrain responsiveness to on-board comfort. A key testing procedure known as 'cold soak' involves leaving the truck outside overnight with the engine off until every component reaches below-zero temperatures. After 12 hours in these extreme conditions, engineers expect the vehicle to start and run perfectly, just as a driver would want it to in the real world.

The floor goes to the test manager

Arctic testing requires careful planning by engineers, who must collect and process enormous amounts of data, combine it with feedback from drivers and translate it all into useful suggestions for improving the product and preventing malfunctions. 

Allestimenti & Trasporti addressed these and other aspects of testing in an exclusive interview with Matthew Taylor, Group Manager for Reliability Test Engineering at Volvo Trucks. "Testing in extreme conditions," explains Taylor, "is part of the Volvo Group's global protocol, called RT, Reliability Testing, which involves specific mileage in a range of temperatures, with some differences from one geographical area to another across the globe to take into account the specific operating conditions of the vehicles. Underlying everything is a long (it can even take several weeks) and meticulous planning process to ensure that all the necessary data is collected. For example, we install specific sensors and communication channels on the vehicle for certain components, such as the powertrain or the cab. We have thermocouples, probes and accelerometers to determine noise levels, mechanical stress and vibration intensity. All the information is sent to data loggers, while an on-board modem transmits the collected parameters to a remote server in real time. 

How have tests evolved over the years? How have procedures changed? The test setup has remained virtually unchanged over time, with a few corrections and additions dictated by experience. Obviously, there have been improvements in the instrumentation, with the adoption of an increasing number of data loggers and communication channels. In addition, we have learned how to make the most of time intervals and test routes for information gathering."

How cold starts are monitored

Can you explain in detail how the 'cold soak' test is performed? "This is a test focused on the powertrain components, which is not performed every day. A prerequisite is that drivers finish their driving shift between 4 and 5 p.m. There are two types of tests: with the vehicle parked outdoors and connected to an engine block heater (the most common situation in everyday operation) or without any external assistance. In the latter case, we check at what temperature the supercapacitor responsible for ignition stops working or when the lubricant is too thick to circulate in the system. We can also monitor any misfires and operating irregularities that lead to excessive hydrocarbon levels, or determine the timing of the gas after-treatment system. Finally, it should be noted that the adoption of a supercapacitor on the new VNLs is a great help in cold starts. In fact, it allows start-up times to be shortened without resorting to the electrical discharge from the battery pack. 

Are there any special tests for cab comfort? The new heavy-duty vehicles are equipped with a cooler and a cab heater, which are tested in both winter and hot weather conditions to ensure the right temperature without running the engine at idle speed. For testing, we have thermocouples in front of and behind the curtains, near the driver's seat and at the ventilation outlets. Once again, as with other components, the data collected by the sensors and the feedback from the drivers allow us to evaluate the effectiveness of the system and understand if, for example, there are any air leaks from the outside caused by a seal, which compromise the maintenance of the optimal microclimate." 

During testing, drivers' opinions are cross-referenced with the data collected. How does this procedure work? "Both aspects are important in obtaining high value-added information for product development and improvement. A data recorder is installed on each lorry. In addition, each driver has a switch on their seatbelt that allows them to start a special recording if an unexpected event, breakdown, malfunction or pop-up message occurs. This procedure, which serves to report an anomaly early on, helps technicians to correctly interpret the data collected and prepare any specific questions for further investigation."

Global tests, but with different nuances

The United States has different climatic conditions and orographic profiles than Europe. How are these factors taken into account in the tests? "The team responsible for vehicle reliability testing works globally with standardised protocols. However, the conditions of use of the trucks, specific regulations and terrain characteristics must be taken into account. In North America, lorries have to cope with heights and gradients that are not found in Europe. For example, gradients of 6-7% for over 15 miles (over 24 kilometres). There are differences in speed (80-90 km/h in the EU compared to 104 km/h in the US) and maximum permissible loads (80,000 pounds, or 36 tonnes, in the US compared to 40-44 tonnes in Europe), but also in the number of daily driving hours (11 in America compared to 9 in Europe). This means that in North America, in a single shift, you can cover the distance between Denver (Colorado) and the Arizona desert, crossing completely different climatic zones.

Source：ITOY