Why does the engine speed increase when braking downhill in a Corolla?
2 Answers
When encountering a downhill slope, the Corolla's speed increases due to inertia. However, the engine's logic is designed not to upshift or allow the car to go faster downhill, maintaining the current gear. To ensure the speed and gear remain unchanged, the engine speed increases. This is a normal phenomenon. Structure of the car brake pedal: The car brake pedal is located below the steering wheel. Pressing the brake pedal causes the brake lever to be pressurized and transmitted to the brake pads on the brake drum, which then clamp the brake disc. Function of the car brake pedal: To slow down or stop the car. The manual brake in a car is located next to the gear shift and is connected to the brake lever. Common examples also include bicycle brakes, which rely on rod-shaped brakes fixed to the frame or disc caliper brakes to slow down.
I've been driving for many years, and it's actually quite normal for the Corolla's RPM to increase when braking downhill. This is mainly because the transmission is helping to slow down the car. Specifically, the Corolla's CVT transmission is very intelligent. When going downhill, gravity causes the car to accelerate, and when you apply the brakes, the system automatically adjusts the gear ratio to increase the engine RPM for additional braking. This is called engine braking, similar to downshifting in a manual transmission car. It uses the engine's compression resistance to slow down the car and prevent the brake system from overheating. Especially during long descents, relying solely on the brake discs could lead to excessive wear or even failure. So this isn't a malfunction but rather a self-protection design of the car, which also helps save fuel. I suggest everyone not to panic and just observe whether this happens on flat roads next time.
