18
2026
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05
Inadequate auxiliary braking: Be cautious / strictly avoid in certain situations; remember the scenarios.
In recent years, the popularity of auxiliary braking devices has been widely applied to domestic heavy-duty truck products, and more and more truck drivers have begun to understand and recognize the help that auxiliary braking devices provide for safe driving.
However, the editor found that many truck friends still have some 'misunderstandings' about auxiliary braking devices. For example, it is common for truck enthusiasts to ask: 'Can auxiliary brakes be used on icy and snowy roads?' The answer is simple: on extreme road conditions such as icy and snowy roads, auxiliary brakes must be used with caution or not at all!
● What types of auxiliary braking devices are there?
First, we need to clarify a concept: what is an auxiliary brake? What techniques are there? The ABS, ESP, EBD, ABS EBD systems we often talk about are not strictly considered auxiliary braking devices. These functions are auxiliary systems for active braking, which we call electronic assistance systems (driver assistance systems).
So what exactly is an auxiliary braking device? Simply put, unlike the traditional braking methods we are familiar with (brakes), an auxiliary brake is a device that helps the vehicle slow down. Currently, the most common auxiliary braking devices we see are exhaust brakes, engine brakes, and retarders (electric eddy current and hydraulic retarders).
● Auxiliary brakes are not omnipotent — use with caution or not at all on icy or snowy roads
Although truck safety technology is currently fairly advanced, these technologies are not "invincible." The use of active safety devices such as ABS, EBD systems, and auxiliary braking devices is subject to certain conditions and scenarios; they cannot ensure drivers' "absolute safety." Proficient driving skills and cautious driving are the "primary requirements" for the operational safety of drivers.
Exhaust brake: Under general circumstances, the exhaust brake butterfly valve is installed on the engine's exhaust manifold. By closing the engine's exhaust passage, the engine pistons encounter reverse pressure from the gases during the exhaust stroke, slowing down engine operation and producing a braking effect, thereby achieving the purpose of controlling the vehicle's speed.
In icy and snowy road conditions, if you are driving a tractor only, you can appropriately and cautiously use the exhaust brake depending on the vehicle's condition. However, if you are driving a tractor with a trailer, using the exhaust brake will cause the tractor to decelerate, which can easily lead to the trailer pushing the tractor. In icy and snowy road conditions, tractors with trailers must avoid using the exhaust brake.
Engine braking: Release the accelerator pedal and use the compression resistance generated during the engine's compression stroke, along with internal friction and intake/exhaust resistance, to create a braking effect on the drive wheels.
Currently, the engine brakes on the market mainly include the Jacobs in-cylinder braking system, the iBrake system used by Foton Cummins, and the FCB system independently developed by FAW. The braking torque is much higher than that of ordinary exhaust brakes, so they must be used with caution on wet or snowy roads. On black ice, the use of engine brakes is strictly prohibited, as the likelihood of head-on collisions, skidding, and rollover accidents is very high.
Retarder braking: Retarder brakes can be classified by type into electric eddy current retarders and hydraulic retarders, by medium into oil medium retarders and water medium retarders, and by installation method into series retarders, parallel retarders, and independent retarders. This will not be elaborated further here.
The electric eddy current retarder device is installed between the vehicle's drive axle and the transmission, and achieves contactless braking through the principle of electromagnetic induction.
In simple terms, a hydraulic retarder achieves continuous wear-free braking by generating torque through the interaction between the stator and rotor in a hydraulic or water medium, thereby reducing the vehicle's speed.
Because the braking torque of the hydraulic retarder is higher than that of engine compression braking and exhaust braking. In extremely severe weather conditions, it cannot suddenly enter full-on mode; sudden excessive deceleration can easily cause vehicle rollover or nose diving. Although currently vehicles can link with ABS or AEB systems, and when vehicle slip is detected, the driving computer will cancel the hydraulic retarder command, it is still necessary to use the hydraulic retarder cautiously on slippery roads just in case. On icy and snowy roads, especially on black ice, the use of retarder devices is similarly prohibited.
● Editor's Note
Although the current various safety technologies have gradually reduced the probability of danger during driving, as mentioned earlier, these auxiliary braking technologies are not 'invincible' devices. Especially in rainy, snowy, slippery, or black ice road conditions, auxiliary braking devices should still be used with caution or not used at all. In extreme road scenarios, we should adopt a cautious low-speed driving mode or even stop driving, because safety is, after all, the most important 'top priority' in our operational life.
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