Hill Hold Control & Hill Descent Control

Hill Hold Control / Hill Start Assist

Hill hold control (HHC) is driving assistance active safety features on a modern car. The main purpose of the hill hold control is to prevent rollback when starting the car on steep road conditions or stopped on the inclined hilly road, have to resume driving forward. This system helps that beginner drivers on uphill or steep hill road conditions, it is also called hill start to assist.

Hill hold control system coordinate with input devices like wheel speed sensor, brake pedal sensor, clutch switch, gear position sensor, accelerator pedal sensor working on it.

Hill Descent Control / Downhill Assist Control 

This feature also works on like Hill hold control system but the different way on the opposite direction can be used downhill or steep declined road condition. It helps ensure a safe speed downhill. The vehicle is moving slower below 30 km/hours, maintaining a constant speed for the descent. Without having to the brakes and accelerator pedal only control of steering wheel. That is why many of them are also called downhill cruise control or downhill assist control.

This system communicates with Antilock brake and Traction control maintaining control of the vehicle by travelling at safe speed downhill, but make sure to reduce your vehicle speed before features activation.

How does it work

The hill hold and hill descent control are active safety features that mainly work on the basic of braking force applied on the vehicle drive hills road conditions especially inclined and declined road. 

Hill hold control to prevent your vehicle from rolling backwards when you change from the brake the accelerator pedal, it works few seconds so you can control the situation or driver manage to vehicle forward. Once the driver has activated hill descent control take the help of the Anti-lock Brakes system ABS, and the Traction Control system to work on it, the required braking force applied for the Hill Control function is calculated based on the amount of force required to keep the vehicle hold. With the help of various inputs devices like wheel speed sensor, master cylinder pressure sensor clutch switch accelerator pedal sensor coordinate with the system is activated and maintain the appropriate brake force until the accelerator pedal is applied in the manual gearbox or transaxles. But in automatic transmission has no trouble in such cases on these road conditions. The same function applies to hill descent control and controlling vehicle speed driving on downhill or other decline roads.

Nowadays all high-end variant car-like Sport Utility Vehicle(SUV) Compact SUV, premium Saden car inbuilt on these features in India market.