Truck Brake Analysis: From Traditional Hydraulic Brakes to Electronic Braking Systems, Which Is the Best Solution?

Truck drivers all know that due to the heavy loads, trucks require very high braking performance. With total weights of several tons, failing to brake properly can result in anything from vehicle and cargo damage to major traffic accidents. 

Therefore, a reliable, efficient, and responsive braking system is the "lifeline" of every truck.

Today, let's take an in-depth look at the common types of brakes carried by light trucks, analyzing their technical principles, advantages and disadvantages, and suitable scenarios.

Traditional Hydraulic Brakes: Classic Structure and Performance Bottlenecks

First, the most common is the hydraulic braking system. This is the most widely used type of brake in passenger cars and can also be found on some light trucks, microtrucks, and early trucks.

The core principle is using brake fluid as a medium to transmit pressure. Because liquids in a closed system are nearly incompressible, they can effectively convey pressure.

 

When the driver steps on the brake pedal, it first activates the vacuum booster pump, which applies pressure to the piston in the master brake cylinder. The master cylinder then pushes the brake fluid throughout the entire brake line. The pressure is transmitted through the brake lines to the brake calipers at each wheel. Under the force of the hydraulic pressure, the pistons in the calipers move outward, pushing the calipers and causing the brake pads to tightly clamp the rotating brake discs, generating strong friction to slow down or stop the vehicle. 

The hydraulic brake system has clear advantages: it has a relatively simple and mature structure, lower manufacturing and maintenance costs, and can provide sufficient braking force to meet regulatory requirements for lighter vehicles. The components of the system are highly interchangeable, making maintenance and repair convenient.

However, the system’s drawbacks are somewhat significant for trucks, with the primary issue being response speed. Although hydraulic fluid is incompressible, its viscosity causes some delay in flow over long brake lines, resulting in a longer feedback time from pressing the pedal to generating braking force. For household cars, this time may not have much impact, but for heavy trucks with large inertia, even a delay of a fraction of a second can mean an increase in braking distance.

 

Secondly, there is the issue of thermal fade. Continuous or frequent braking can cause the brake pads and discs to reach extremely high temperatures. This heat can transfer to the brake fluid, potentially leading to a soft brake pedal and a significant reduction in braking efficiency, which is extremely dangerous on long downhill sections. Furthermore, the system requires very high sealing integrity, as any fluid leak in any part can directly lead to brake failure.

Therefore, although hydraulic brake systems are classic, when it comes to heavy-load trucks that demand frequent braking, their performance limitations gradually become apparent.

Air Brakes: The Reliable Foundation for Heavy-Duty Trucks

Due to the limitations of hydraulic brakes on heavy trucks, air brakes have almost become the standard configuration for freight trucks. As the name suggests, air brakes use compressed air as the medium to transmit braking energy.

The core of an air brake system lies in a dedicated air supply and processing unit. The air compressor continuously draws in air, which first passes through a dryer—a crucial component that effectively removes water and impurities from the air, ensuring that the air entering the system is clean and dry—before being stored in the vehicle’s air tank, ready for use at any time.

 

When the driver presses the brake pedal, what is actually being operated is the brake valve. The valve opens, and high-pressure air from the air tank flows through the pipelines to the brake chambers at each wheel. This pushes the pistons in the brake chambers to generate tremendous force, ultimately causing the brake pads to clamp the brake discs and achieve braking. 

The advantages of air brakes are also quite obvious. First, they have a short response time; the speed of air flow is much faster than that of hydraulic fluid, resulting in more timely brake response. Second, they are powerful; the high pressure of compressed air can easily drive the braking mechanisms of heavy trucks that require enormous braking force. Third, they are safe; even if the engine stops or the compressor ceases operation, the air stored in the tanks can still provide multiple effective braking actions. Fourth, they have good resistance to heat fade; since the medium is air, it is not affected by air resistance caused by high temperatures, ensuring better stability.

 

Of course, the drawback of air brakes lies in their complex structure and greater number of components, including air compressors, dryers, air tanks, various valves, and air lines. Maintenance costs are higher, and they require regular drainage, inspection of the dryer, and maintenance of pipeline seals, making upkeep more professional and demanding.

However, weighing the factors, for heavy-duty trucks, especially those that frequently carry heavy loads or operate in mountainous and complex terrains, the reliability and braking performance provided by air brakes make them synonymous with safety and reliability, earning the trust of many truck drivers.

Technological Innovations: The Rise of ONE BOX Line Control Brakes and Electric Brakes

With the popularization of new energy trucks, electronic and electrified architectures have provided a new perspective for brake system innovation. The gradual replacement or assistance of physical pressure transmission with electronic signal transfer has become a new technological direction, giving rise to advanced technologies such as ONE BOX line control brakes and BYD electric brakes.

What people should understand is that when a driver presses the brake pedal, they are not directly applying braking force but sending a "brake request" signal. In traditional systems, this signal is transmitted through physical changes in hydraulic or air pressure. In line control brake systems, it is first converted into an electronic signal.

The ONE BOX line control brake system is a highly integrated electro-hydraulic brake system. It combines traditional components such as the vacuum booster, master brake cylinder, and ESP/ESC units into a single compact module. When the driver presses the brake, the pedal travel sensor immediately detects the braking intention and required force, converting it into a precise electronic signal sent to the control unit. The control unit then processes vehicle status variables such as speed, load, and wheel speed, calculates the necessary action, and sends instructions to the motor, which drives the hydraulic mechanism to apply pressure to the wheel cylinders, achieving braking.

 

Its advantages are: First, extreme responsiveness. Electrical signal transmission is almost instantaneous, significantly reducing brake response time and helping to shorten braking distances. Second, precise control. It can achieve millisecond-level pressure adjustments, coordinating more smoothly with the drive system and energy recovery system. This not only makes braking smooth and linear but also maximizes energy recovery efficiency, increasing vehicle range. Third, high integration, saving space, reducing weight, and simplifying pipeline layout. Fourth, it can seamlessly connect with the vehicle's own ACC, AEB, and other systems, allowing the control system to execute braking commands directly and quickly.

Not long ago, we tested the Jinhu ET50, which is equipped with the ONE BOX by-wire braking technology. In actual experience, its brake response is very tactile, with almost no pedal free play, providing clear and linear braking feedback from the initial stroke. As the pedal is pressed deeper, braking force increases evenly and powerfully. This intuitive "the more you press, the more force you get" sensation can give drivers greater confidence and a stronger sense of safety.

 

In addition, BYD's electric brake is also a representative of this technological route. It applies BYD's powerful electronic control technology to truck braking systems, enabling rapid and precise distribution and adjustment of braking force through electronic control. It similarly aims to optimize response speed, improve braking linearity, and, while ensuring braking performance, significantly enhance energy utilization efficiency.

Summary

Truck brakes are by no means just a simple combination of parts; they are a core system related to the safety of life and property during transportation. The evolution of technology has always focused on the goals of faster, stronger, more stable, and smarter performance.

In the traditional domain, air brakes are highly recognized by drivers for their proven reliability and strong braking force. However, in the wave of new energy and intelligent technologies, innovations like ONE BOX line-controlled brakes, through electronic and integrated technologies, demonstrate great potential in response speed, control precision, and system coordination.

For end users, whether choosing the mature and reliable air brakes or embracing cutting-edge line-controlled brakes, ultimately the choice needs to match their own load requirements, operating conditions, and overall vehicle configuration. After all, the one that fits best is the safest.