What are the key differences between electric and hybrid vehicle dynamics?

2 Hybrid vehicles

Hybrid vehicles (HEVs) combine an ICE with one or more electric motors, batteries, and a power management system. The main advantage of hybrid vehicles is that they can switch between different modes of operation, such as electric-only, engine-only, or blended, depending on the driving conditions and the driver's preferences. This allows them to optimize their fuel economy, emissions, and performance. However, hybrid vehicles also have some drawbacks, such as increased complexity, cost, and weight of the powertrain, as well as potential conflicts between the engine and the electric motors in terms of speed, torque, and control.

3 Vehicle dynamics models

Vehicle dynamics models are mathematical representations of the forces and motions that affect a vehicle's behavior. They can be used to analyze and improve the performance, efficiency, and safety of different types of vehicles. Vehicle dynamics models typically consist of four main components: longitudinal dynamics, lateral dynamics, vertical dynamics, and steering dynamics. Longitudinal dynamics describe the acceleration and braking of a vehicle, lateral dynamics describe the cornering and stability of a vehicle, vertical dynamics describe the suspension and ride quality of a vehicle, and steering dynamics describe the steering and handling of a vehicle.

4 Electric vehicle dynamics

Electric vehicle dynamics are influenced by the characteristics of the electric motors, batteries, and power electronics that make up the electric powertrain. Regenerative braking, torque vectoring, and a low center of gravity are three key aspects that can impact the performance of electric vehicles. Regenerative braking allows for energy to be recovered from kinetic energy which reduces brake wear and increases battery life. However, this also affects the brake feel, brake balance, and ABS of electric vehicles. Torque vectoring distributes different amounts of torque to each wheel depending on the driving situation, which can improve traction, stability, and agility. This also increases power consumption and thermal stress on electric motors. Lastly, a lower center of gravity improves roll stability and cornering performance of electric vehicles but reduces ground clearance and off-road capability.

5 Hybrid vehicle dynamics

Hybrid vehicle dynamics are influenced by the interaction between the ICE and the electric powertrain, as well as the power management system that controls them. These dynamics involve mode switching, engine start/stop, and power split. Mode switching allows hybrid vehicles to use the most efficient or suitable power source for each situation, improving fuel economy, emissions, and performance. However, this also introduces challenges for the smoothness, responsiveness, and consistency of hybrid vehicles. Engine start/stop reduces fuel consumption, emissions, and noise of hybrid vehicles by avoiding unnecessary engine operation. Nevertheless, it also affects vibration, comfort, and reliability of hybrid vehicles. Finally, power split optimizes efficiency, performance, and stability of hybrid vehicles by using the best combination of power sources for each scenario. Nonetheless, it increases complexity, cost, and weight of the powertrain as well as potential conflicts between the engine and the electric motors.

6 Comparison and implications

Electric and hybrid vehicle dynamics differ from each other and from conventional vehicle dynamics in various ways, with implications for drivers, engineers, and the environment. Electric vehicles have higher acceleration and lower power at high speeds, while hybrid vehicles have variable acceleration and power depending on the mode of operation. Regenerative braking and torque vectoring are features of electric vehicles, while hybrid vehicles have mode switching and engine start/stop. Electric vehicles have lower center of gravity and higher weight than conventional vehicles, while hybrid vehicles have similar center of gravity and higher weight than conventional vehicles. In terms of emissions and noise, electric vehicles are lower than conventional vehicles, while hybrid vehicles are lower than conventional vehicles in some modes of operation. All these differences affect the performance, drivability, range, efficiency, stability, agility, smoothness, responsiveness, consistency, roll stability, cornering performance, ride quality, environmental impact, comfort, and perception of both types of vehicles.