Vehicle & Component Durability Sensors
Accelerometers, Load Cells, Force Sensors, and Signal Conditioners
Vehicle & Component Durability
Due to the increasing competitive pressure in the global Automotive Industry, vehicle development schedules have decreased from 4-5 years a decade ago, to less than 2 years today. This has allowed manufacturers to react more judiciously to changing consumer demands, market conditions, and legislative requirements. The challenge for the vehicle development community is to meet these condensed timelines without negatively affecting quality and performance attributes such as warranty, fuel economy, crash worthiness, NVH (Noise, Vibration, and Harshness), and driver comfort. At the most fundamental core of any development program is vehicle and component durability testing. The success of a durability program lies in its ability to replicate the summation of all major inputs a vehicle would likely see in its operating environment in the shortest time possible. A poorly executed durability program can cost a manufacturer millions in warranty costs, reduced sales, and a loss of customer loyalty. In order to expedite durability testing without sacrificing due diligence, many vehicle manufacturers have adopted virtual development methods that are coupled with traditional durability testing. With these virtual techniques, however, comes more scrutiny on the reliability, repeatability, and accuracy of the limited physical tests.
Robustness, flexibility, reliability and fidelity of sensors and instrumentation are compulsory for any successful durability test program. It is rarely feasible for a complete durability program, or a significant portion of it, to be repeated due to faulty equipment or sensors. PCB® designs sensors with these requirements in mind to support compressed product development time and to ensure that a vehicle, system, and component is measured successfully and accurately the first time. A typical durability test program consists of the following key test elements:
Full Vehicle Durability
Road load tests measure the transient and steady state inputs of a vehicle as it operates over a road surface in the intended market region or over a replicated drive profile on a test track. The road load test accounts for vehicle and driving parameters such as mass, inertia, air & rolling resistance, road characteristics, engine loads, and vehicle speed.
Data gathered from Road Load Data Acquisition (RLDA) is processed and analyzed and used for control of a powertrain/chassis dynamometer in the case of a powertrain durability program; or multi-axis hydraulic shakers for a vehicle structural durability program. Simulated durability programs are separated as it becomes almost impossible to control both load profiles. Full vehicle durability can be performed in its entirety, with both powertrain and chassis induced loads, on a test track with a drive profile that replicates the road surface and vehicle speed necessary for the intended geographical region. While vehicle durability testing on a test track offers the most realistic load cases, it often takes longer to complete and is dependant on the current ambient conditions only, not the specific conditions that are necessary. Simulated powertrain or vehicle structural durability, on the other hand, offers more repeatable test outcomes in an expeditious manner.
Component Durability
Many vehicle systems and components experience complex static, dynamic, and thermal loading conditions when operated. Data gathered from road load or vehicle durability results are used to simulate these load conditions in a lab where forces and ambient temperatures acting on the test subject can be controlled. Climatic chambers are used for specific control of ambient conditions including temperature and humidity while multi-axis shaker systems can control up to three axis of motion simultaneously and independently. For controlled component durability testing, where control of the inputs and the response of the test object are crucial, PCB® offers robust quartz accelerometers with high sensitivity and excellent resolution that are well-suited for this demanding application. For tests requiring tight control of inputs over large temperature variations, PCB® Series 339A low temperature coefficient triaxial ICP® accelerometers, ensure accurate representation.
Strain Gage Load Cells for Durability Applications
PCB® general purpose load cells are suitable for a wide range of routine static force measurement applications, including vehicle and component durability application testing. PCB® Series 1403 low profile load cells are rugged devices manufactured using premium heat-treated, fatigue-resistant steels and are ideal for component testing.
DC Response Accelerometers for Durability Applications
PCB® Series 3741 DC response accelerometers are offered in a variety of full-scale ranges, from ± 2 to ± 200 g, to accommodate vehicle and component durability testing requirements. The units feature silicon MEMS sensing elements for uniform, repeatable performance. Gas damping, mechanical over range stops, and a low profile, hard-anodized, aluminum housing are utilized for added durability. Electrically, the units offer a differential output signal for common-mode noise rejection. PCB® Series 3711 (single axis) and 3713 (triaxial) DC response accelerometers are designed to measure low-frequency vibration and motion, and are offered in full-scale ranges from ± 3 to ± 200 g, to accommodate a variety of vehicle and component durability testing requirements. The units feature gas-damped, silicon MEMS sensing elements that provide performance, while hermetically sealed titanium housings provide protection from harsh contaminants. These units are inherently insensitive to base strain and transverse acceleration effects, and offer high frequency overload protection. Electrically, the units offer a single-ended output signal for each channel with power and ground leads.
Small, Lightweight, Single Axis, ICP® Accelerometers for Durability Applications
Specific vehicle and component durability application testing requires small, lightweight accelerometers for high-frequency response, low noise, minimal mass loading, and installation in space restricted locations. PCB® offers a line of ceramic shear ICP® accelerometers, Series 352, housed in lightweight aluminum or robust hermetically sealed titanium. By minimizing the mass of the sensor, mass loading effects are reduced, leading to improved measurement accuracy.
Low Temperature Coefficient, Triaxial, ICP® Accelerometers for Durability Applications
PCB® Series 339A Triaxial, ICP® accelerometers are designed with a low temperature coefficient, wide operating temperature range, and good broadband measurement resolution, making them ideal for any vibration measurement requiring tight control of amplitude sensitivity over a wide thermal gradient. With a temperature coefficient of less than 0.0125% / °F (0.02% / °C), these sensors provide precision amplitude data for test applications with large thermal shifts such as durability testing in a climatic chamber.
High Temperature, Triaxial, ICP® Accelerometers for Durability Applications
High temperature, ICP® accelerometers, Series 320, are specially designed and tested to survive temperature extremes beyond the range of standard ICP® accelerometers. These sensors are ideal for use in engine, turbo, exhaust and other high temperature vehicle and component durability testing environments.
Quartz Shear, ICP® Accelerometers for Durability Applications
PCB® quartz sensing crystals, Series 353B and 357B offer the most stable operation over time with virtually no change in sensitivity and performance even after multiple overload events. Measurement accuracy is improved in vibration testing that incorporates thermal cycling due to the quartz crystal's low temperature coefficient properties. Titanium housings provide lightweight construction for maximum frequency range and to minimize mass loading, as well as provide excellent protection against many corrosives.
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