What is Hill Hold Control?

The hill-hold control prevents the car from rolling back when the driver begins driving from a stationary place on a slope, hill, or other inclined surface.

When drivers remove their feet from the brake and apply the accelerator, they risk rolling back when driving up a hill. Inexperienced and novice drivers are particularly vulnerable to this.

For such situations, the hill hold control system provides enough time for the driver to drive the car on the climb by holding the brake for a few seconds longer.

The system operates with two sensors. The accelerometer calculates a slope's longitudinal gradient while the other engages or disengages the braking system. Your car's hill-hold control automatically activates when a sensor on the accelerometer detects an incline. When you release the brake and accelerate, Hill-hold control keeps the vehicle stable for a few seconds longer, giving you time to shift into gear or accelerate in an automatic gearbox.

A hill-hold control system releases the brakes once the engine has sufficient power to propel the vehicle forward.

Formerly available only in high-end cars, hill-hold control is now widely available in budget vehicles such as the Tata Nexon, Maruti Suzuki Swift, Kia Sonet, Honda City, Ford EcoSport, and others.

The most common methods for hill hold control in the car are listed below.

Clutch Detection

The most apparent application of hill-start control is in cars with manual transmissions. It would help to press the clutch using the manual transmission before starting the engine. The automobile can roll around without engine braking, mainly on an incline. If the brakes are also off, usually when the car accelerates, the vehicle can also roll freely.

Incline Detection

If your car stops on an uphill with the engine on, you may require the hill-start control. If the vehicle detects an incline more significant than a specific angle, such as three degrees, the hill-start control will signal that the car is about to roll off.

If a tyre falls into a pothole, for example, inclination detection may not detect that the vehicle is on an incline, so hill-start control may not get activated or be necessary at all.

Engine Torque Detection

It determines whether the engine can produce enough torque to move the vehicle. When this occurs, the hill-start control is disabled since the automobile will not likely roll backwards.

Brake Detection

Sensors detect whether or not the brakes are applied in this system. Brake force is also monitored by the sensors when the brakes are engaged. A hill start assist will be activated if the brakes are not strong enough to hold the car in place.

Backward Motion Detection

Some systems may include a way of detecting backward motion even though it's not technically necessary.

As part of incline detection systems, the incline sensor detects whether the vehicle is on a hill. A brake sensor detects the presence of a brake. A car that isn't correctly aligned risks rolling backwards, so the system engages the brakes to prevent this from happening. Manual transmission cars can simultaneously be equipped with clutch and brake detection to detect when the vehicle is in danger of rolling backwards and applying the brakes.

Forward Roll Detection

You must use this system if you reverse your vehicle on an uphill road. A reverse gear indicates that the vehicle is moving backwards; the system understands this. As the car accelerates with the hill start assist engaged, you should hold the brakes for a few seconds to allow smooth acceleration.

Several components contribute to the smooth functioning of hill assist control. The following are some of the parts.

Angle Sensors

Using these sensors, you can measure the angle of the car on an incline by comparing it to the grade of the hill.

Pressure Sensor

A pressure sensor measures the weight of a vehicle, including passengers and cargo, as part of the suspension system. Alternatively, piezoelectric sensors and strain gauges can be used. Electrical signals generated by these sensors indicate vehicle weight.

Torque Sensor

Torque sensors measure the rotational force an engine generates to accelerate a vehicle. The torque sensors measure how much torque the drivetrain transfers to the wheels.

Wheel-speed Sensors

By measuring the rotational speed and direction of wheels, these sensors determine their rotational speed and direction.

Electronic Control Unit

The embedded computer systems in vehicles receive signals from a variety of sensors. Units such as these are called Electronic Control Units (ECUs). Based on this information, the ECU decides when to apply the brakes. By analysing the weight and slope of the hill, the ECU can calculate the moving resistance of the car based on the pressure and angle sensors. The engine torque is calculated based on the travelling resistance that helps to move the vehicle uphill,

Brake Actuator

Electrical signals are converted into physical movement by the brake actuators. The ECU instructs the brake actuator to apply the brakes by sending a signal. The brake valves are activated, sending brake fluid to the brakes to prevent the car from rolling back down the hill. Instead of braking, a hybrid vehicle can use its electric motor to provide forward motion so it does not roll backward.

The hill-start assist system in your car operates automatically, so there is no need to follow any particular procedure. It is generally an automatic function that controls the hill-hold. The system may be toggled on and off with a button on some cars. To make sure the system works, you may need to switch it on. The rest of the process is straightforward; you can drive as usual.

An automatic car with a hill-assist is slightly different from a manual car. This is explained in the following section.

Hill Assist with Manual Transmission

Following these **Steps, you can drive your manual car on an incline with hill assist control.

Step 1: Engage the clutch and release the brake pedal simultaneously.

Step 2: If the transmission is in "Neutral," shift to 1st gear.

Step 3: Pull your foot away from the brake pedal. Accelerate steadily while releasing the clutch slowly.

Step 4: The hill-hold control should prevent the car from rolling back until you accelerate.

Below are examples of some vehicles in India with manual transmission hill assist control.

• Tata Nexon

• Honda City

• Hyundai i20

Hill Assist with Automatic Transmission

The following **Steps can be followed if you drive an automatic transmission car.

Step 1: Start the vehicle by pressing the brake pedal.

Step 2: Put the gear knob in the "Drive" or D position.

Step 3: Using the accelerator, **Step off the brake and drive forward.

Step 4: When you accelerate, the car should not roll back, as the hill start assist holds the brakes temporarily.

The following is a list of automatic cars with hill-hold control in India.

• Maruti Suzuki Dzire

• Maruti Suzuki Celerio

• Hyundai Venue

• Maruti Suzuki Swift

Maruti Suzuki Ertiga

One of the most affordable cars in India with hill hold control assistance is the Maruti Suzuki Celerio.

The following are some other models of Maruti having hill hold control.

• Maruti Suzuki Wagon R

• Maruti Suzuki Swift

• Maruti Suzuki Baleno 2023 comes with ESP and hill hold control as standard in manual and automated transmission variants.

Motors used in EVs are highly versatile, and controller algorithms can implement forward and backward torque. Thus, electric vehicles can quickly implement hill hold features compared to cars with IC engines.

Sensors detect the slope angle and position of the vehicle in electric vehicles to control hill hold features. It is a standard safety feature in many electric cars that can be turned on and off at the driver's discretion.

Regenerative braking is often part of the hill hold feature in electric vehicles. In regenerative braking, the car's battery is recharged by capturing the energy usually lost when it brakes. With the hill hold control system, the regenerative braking system applies enough brake pressure to prevent the car from rolling backwards but not enough to drain the battery. The vehicle will be braking electrically instead of mechanically.

A hill hold control system can be installed in your old car. However, aftermarket systems are not recommended. In addition, installing such a system could be pretty expensive, and it might even void your vehicle's warranty from the manufacturer. As a result, it is a good idea to choose a car with a factory-fitted hill assist system if you intend to buy one.

The following are some of the benefits of a hill assist control system:

Individuals can drive more quickly when driving uphill or on steep slopes. It also helps beginners learn to drive on manual transmissions in a safe environment.

Vehicle components are less likely to wear out due to this system. A clutch plate, a handbrake, and a brake are among these components. With hill hold control, you can prevent wear and tear on the car parts when a driver's assistance system is flawless. This will prevent additional strain on certain car parts.

As this system prevents a vehicle from sliding backwards while going uphill, it rescues the vehicle just behind and prevents a collision.

Having hill start assist on your vehicle will help avoid accidents in hilly areas. Major car brands began adopting this technology around 2005, decades after it was first introduced to the market in 1936. As a result, it has become an essential driver's assistance system when buying a new car today.

The following are some of the popular hill assist cars in India.

When equipped with Hill-Hold Control, the vehicle does not roll back on an inclined surface like a hill or slope. With it, driving uphill becomes easier. As a result, beginners can safely operate a car, especially if they are driving for the first time.

Almost all modern cars are fitted with hill hold control because it has become an essential feature. But there is another essential for car owners, and that is car insurance purchase. It is rather a govt. Mandate to have an active car insurance policy. So, if you are planning to get a new car, choose Tata AIG's motor insurance to protect you and your vehicle. Tata AIG makes car insurance claims and car insurance renewals easy.

Can the hill-start assist be used on all hills?

The system should work on any incline as long as the hill-start assist works correctly. Occasionally, if the slope is too steep, hill hold control may fail to prevent the vehicle from rolling back.

Is a hill assist system standard on all automatic cars?

Modern automatic cars often come with hill assist features, but it is advisable to check the list of features before taking the final call.

What causes a problem with Hill Start Assist?

Battery power is required for the hill start assist system to function correctly. You may notice a warning light or a message warning you that "hill start assist unavailable" if the battery voltage is too low.

What is the time limit in Hill Hold Control?

Hill-start assist control or Hill Hold Control automatically applies the brakes for approximately two seconds to prevent the vehicle from rolling back.

Can the Hill Hold Assist feature fail?

The car's ECU or a mechanical issue may cause the hill holder to refuse to release the brakes or not engage it at all.