What is the foot brake?
2 Answers
The foot brake is the service brake. The service brake is a braking device that stops or reduces the speed of a moving vehicle. It achieves braking through intense friction between the brake pads and the brake drum. In contrast, the handbrake is a parking device and should not be used for braking during driving except in emergencies. Here is a related introduction to the classification of braking systems: 1. Throttle control braking: When deceleration is needed, maintain the 3rd gear position and fully release the throttle. At this point, the engine tends to idle, creating resistance in the drivetrain that acts on the wheels to slow the vehicle down. 2. Exhaust brake: High-power diesel engines have a butterfly valve at the connection between the exhaust manifold and the exhaust pipe. In gear, operating the electromagnetic switch closes the valve, causing the engine to stall and achieve braking. It automatically opens when the throttle is pressed again. Simple in structure but harmful to the engine. Commonly used in heavy trucks and buses. 3. Hydraulic torque converter retarder: A turbine chamber is added at the rear of the transmission housing. When the braking circuit is activated, transmission oil generates damping in the turbine to achieve braking. No wear but requires additional cooling. Currently used in ZF transmissions for high-end buses. 4. Electric turbine retarder: Essentially a "generator" installed on the driveshaft. When not powered, there is no contact or wear. When braking is needed, the circuit is activated, and the driveshaft is subjected to electromagnetic resistance to achieve braking. No wear but bulky in structure. Optional for heavy trucks and buses. 5. Engine braking structure: The braking signal slightly opens the exhaust valve without closing it, creating airflow resistance during piston movement to generate braking force. Compact and non-damaging, currently not available domestically.
Recently a friend asked me about the foot brake, so I’ll share my understanding. The foot brake is the pedal you press with your right foot while driving, officially called the service brake system, primarily responsible for slowing down and stopping the vehicle. It serves a different purpose from the handbrake—the handbrake keeps the car stationary, while the foot brake controls deceleration during motion. Every day during my commute, when I hit a red light and press the foot brake, the car transmits force through the hydraulic system to the brake pads at the wheels, using friction to bring the vehicle to a stop. Having driven over a dozen different cars, I’ve noticed that foot brake responsiveness varies by make—Japanese cars tend to have a softer pedal requiring deeper presses, while German cars feel firmer with quicker braking response. If the foot brake feels spongy, it’s likely due to brake fluid leakage or air in the system, which needs immediate attention. Friends who frequently drive mountain roads should also beware of overheating from constant braking; on steep descents, it’s best to shift to manual mode and use engine braking for assistance.
