What is the Principle of a Chassis Dynamometer?
2 Answers
The basic principle of a chassis dynamometer is to use rollers to simulate the road surface. The various resistances encountered by a vehicle during normal constant-speed driving are simulated through a loading device. The torque and power of the chassis dynamometer are measured by a force sensor installed on a force arm connected to the stator and the dynamometer housing. The fundamental principle of a chassis dynamometer is to simulate the various resistances encountered by a vehicle during normal constant-speed driving through a loading device, allowing the vehicle to accelerate and coast. The resistance experienced by the road surface is simulated using the rotational inertia of a flywheel assembly. By simulating the vehicle under various operating conditions on actual roads, the chassis dynamometer can test the vehicle's performance in terms of fuel economy, reliability, emissions, and power. The key to accurately simulating road resistance lies in the rational design of the dynamometer's loading system, as the control effectiveness of the loading system directly affects measurement accuracy. Automotive Chassis Construction: The automotive chassis structure consists of four parts: the running gear, transmission system, braking system, and steering system. Most modern passenger cars use independent suspension systems, which can be further categorized into longitudinal arm, transverse arm, multi-link, strut, and MacPherson suspension systems based on their structural forms.
I frequently work with chassis dynamometers, and their principle is quite straightforward. Simply put, a vehicle is driven onto the equipment, where the wheels rotate a set of rollers connected to sensors that measure speed and torque data. These measurements are used to calculate the engine's power and horsepower output. Electronic systems control the load to simulate different road conditions, such as uphill acceleration or constant-speed resistance, mimicking real driving scenarios. This device is commonly used in garages to test vehicle performance, diagnose engine or transmission issues, and ensure environmental compliance through emission testing. From my experience, absorption dynamometers can precisely adjust constant loads, while inertial types are better suited for rapid acceleration tests. Overall, it saves time and enhances safety by avoiding the risks of on-road testing. Regular calibration is crucial because sensor accuracy directly impacts the reliability of the results.
