How do you compare vehicle dynamics and control for conventional and electric vehicles?
Vehicle dynamics and control are essential aspects of automotive engineering, as they determine how a vehicle behaves on the road, how it responds to driver inputs and external disturbances, and how it can be optimized for safety, performance, and efficiency. However, conventional and electric vehicles have different characteristics and challenges that affect their dynamics and control. In this article, you will learn how to compare vehicle dynamics and control for conventional and electric vehicles, and what are the main advantages and disadvantages of each type.
One of the most obvious differences between conventional and electric vehicles is the powertrain configuration, which refers to how the engine, transmission, and wheels are connected and controlled. Conventional vehicles usually have a single engine that drives the wheels through a mechanical transmission, which can be manual, automatic, or continuously variable. Electric vehicles, on the other hand, can have one or more electric motors that drive the wheels directly or through a simple gear reduction. This means that electric vehicles have fewer moving parts, lower maintenance costs, and higher efficiency than conventional vehicles. However, electric vehicles also have limitations, such as lower range, higher weight, and longer charging time than conventional vehicles.
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While much focus on EVs has revolved around total range, there often is missing context involved. The total possible driving distance on a single charge has vastly improved with successive new EV model roll outs to the point where some EVs have farther ranges than comparable ICE models. But a better comparison would be to compare efficiency ratings for total range or distance on a tank is influenced by the size of battery pack or gas tank. Both batteries and gas tanks are merely energy storage devices, but the process of converting and utilizing the stored energy heavily favors EVs. Only about 20% of stored energy in gas moves the vehicle whereas the same metric for EVs is more than 80%. EVs are simply more efficient than ICEs.
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Conventional Vehicles vs Electric Vehicles Power Source : Internal Combustion Engines # Electric Motors Torque Delivery: Variable with RPM # Instant, Consistent Transmission : Multi-speed # Single-speed or Direct Weight Distribution: Front-heavy due to engine # Improved due to Battery Regenerative Braking: Not Present # Recovers Energy Control Systems: Engine Management Systems # Battery and Motor Control Handling and Stability: Varied handling # Improved Stability Noise and Vibration: Engine Noise and Vibration # Quieter and Less Vibration Maintenance : More maintenance due to parts # Less Maintenance
Longitudinal dynamics refer to how a vehicle accelerates and decelerates along its longitudinal axis, which is affected by the powertrain, the brakes, and the aerodynamic drag. Conventional and electric vehicles have different longitudinal dynamics due to their different powertrain characteristics. Conventional vehicles have a nonlinear relationship between the engine speed and the torque output, which depends on the throttle position, the gear ratio, and the engine characteristics. Electric vehicles, on the other hand, have a linear relationship between the motor speed and the torque output, which depends on the battery voltage, the motor current, and the motor characteristics. This means that electric vehicles have faster and smoother acceleration and deceleration than conventional vehicles, as they can deliver maximum torque at any speed. However, electric vehicles also have lower top speed and lower efficiency at high speeds than conventional vehicles.
Lateral dynamics refer to how a vehicle turns and maneuvers around its vertical axis, which is affected by the steering system, the suspension system, and the tire forces. Conventional and electric vehicles have different lateral dynamics due to their different weight distribution and center of gravity. Conventional vehicles usually have a front-heavy weight distribution, as the engine is located at the front of the vehicle, and a higher center of gravity, as the fuel tank is located at the bottom of the vehicle. Electric vehicles, on the other hand, can have a more balanced weight distribution, as the battery pack can be located at the center or the rear of the vehicle, and a lower center of gravity, as the battery pack can be located at the floor of the vehicle. This means that electric vehicles have better handling and stability than conventional vehicles, as they have less understeer or oversteer tendencies and less body roll. However, electric vehicles also have higher inertia and lower cornering stiffness than conventional vehicles, as they have higher mass and wider tires.
Control systems refer to how a vehicle is regulated and controlled by various sensors, actuators, and algorithms, which aim to improve the vehicle performance, safety, and comfort. Conventional and electric vehicles have different control systems due to their different powertrain and dynamics characteristics. Conventional vehicles usually have control systems such as anti-lock braking system (ABS), electronic stability control (ESC), and cruise control, which use hydraulic or mechanical actuators to modulate the brake or engine torque. Electric vehicles, on the other hand, can have more advanced control systems such as regenerative braking, traction control, and torque vectoring, which use electric or electromagnetic actuators to modulate the motor torque. This means that electric vehicles have more flexibility and functionality than conventional vehicles, as they can recover energy, prevent wheel slip, and distribute torque among the wheels. However, electric vehicles also have more complexity and uncertainty than conventional vehicles, as they have nonlinear and coupled dynamics and limited battery capacity.
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