Mr. Carlos Agudelo, Link Engineering, UNITED STATES

Mr. Marco Zessinger, Link Europe GmbH, GERMANY

Mr. David Antanaitis, General Motors, UNITED STATES

Mr. Michael Peperhowe, dSPACE GmbH, GERMANY

Current standards like the SAE J2789 have provisions for adjusting the brake inertia for regenerative braking systems. However, a comprehensive method to implement the correct brake blending during inertia dynamometer testing in real-time remains elusive. With Hybrid and Battery Electric Vehicles (BEV) propulsion systems on the rise, the need to develop friction couples and braking systems is ever increasing. To better understand new phenomena related to low-temperature burnish, corrosion, brake balance, NVH, and brake emissions, the automotive industry needs to rely on laboratory testing using inertia dynamometers. The main innovation on the approach presented is the ability to have an actual (ego) brake corner in the test environment to provide real-time torque and temperature response during testing,

This oral-only presentation elaborates on critical aspects of HiL simulation for BEV brake blending. What makes this work unique is the focus on the development of working software and working hardware using software ECUs for the battery controller, particular communication protocols with high-speed scenario simulation, and commercially available hardware (HiL and standards dynamometer platforms), and application to real-life cases and driving cycles. The work presents the software and hardware modules; the algorithms to control the ego brake corner; the communication packets; events, and scenario triggers; and the automation of a test cycle – with practical examples. These developments can support early system evaluation, simulation of static and dynamic scenarios, and expand to include multiple ego brake corners.

Mr. Carlos Agudelo, Link Engineering, UNITED STATES

This presentation provides an overview of recent revisions and current projects for new standards, recommended practices, and information reports from SAE. The presentation incorporates status from several committees working on passenger cars, light trucks, and commercial vehicles, including joint developments with other Standards Development Organizations (SDO) like ISO, JSAE, and VDA.

Mr. Carlos Agudelo, Link Engineering, UNITED STATES

Dr. Eng. Ravi Teja Vedula, Link Engineering., UNITED STATES

Mr. Quinn O'Hare, Link Engineering., UNITED STATES

Dr. Eng. Jaroslaw Grochowicz, Ford Werke GmbH, GERMANY

Dr. Theodoros Grigoratos, European Commission, Joint Research Centre, ITALY

The incoming air during brake emission measurements using inertia dynamometers has two primary purposes: providing a cooling regime that replicates within reason the vehicle brake temperatures and transporting the particles from the friction couple to the sampling plane. Each objective brings its challenges. The ideal cooling system on the inertia dynamometer would have to adjust for factors like a) amount of cooling as a function of vehicle speed and axle position – front or rear; b) wheel well design; c) relative cooling coefficients for the friction couple; d) temperature at the wheel well as function of temperature of the outside air, and the heat dissipation of the brake; and e) wheel and tire design, size, and airflow patterns. The ideal cooling regime to optimize the aerosol sampling would need to: a) have constant airflow during the entire test; b) ensure the air temperature and humidity remain constant at the sampling plane where the brake debris enters the sampling train; c) remain agnostic to the brake size, brake orientation, duty cycle, and potential interactions with the brake enclosure or brake fixture; and d) provide the proper balance of residence time, transport efficiency, and isokinetic sampling for large particles. Since the accomplishment of both sets of objectives conflict, the industry needs a set of compromises to allow the characterisation of brake emissions using laboratory methods, remain representative of the vehicle behaviour, and be practical for implementation during regular testing campaigns.

The laboratory methods to measure brake emissions need to be repeatable and reproducible. Task Force 1 within the Informal Working Group of the Particulate Measurement Program (within the UNECE/GRPE) developed a set of metrics to adjust brake cooling on the dynamometer. This paper presents the results of applying the proposed methodology and metrics to several vehicles from the California Air Resource Board program to update the EMFAC model. The vehicles were instrumented to measure brake activity on the proving ground and interact with the driver during the WLTP duty cycle; which was executed to remain within the target speed error bounds from GTR15. With this information and the brake hardware for each vehicle and axle, the work focused on determining the conditions for the dynamometer cooling air (temperature and airflow) to meet within reason the different PMP metrics.

The results of the experimental validation yielded valuable information to a) determine the cooling airflows for the subsequent inertia dynamometer tests, b) finetune the PMP brake cooling metrics and prepare a proposal for default settings, and c) verify the availability (or design) of isokinetic sampling nozzles for all instruments and sampling lines.

Task Force 1 of the PMP used these findings to complete the methodology for adjusting the cooling air, in cases where there are no direct measurements from vehicle testing or cooling rates applicable to the WLTP-Brake cycle.