Motorbromser

Motorbromser, or engine brakes, are devices or systems that increase deceleration by using the engine to dissipate kinetic energy. They reduce reliance on wheel brakes and help manage brake temperatures, especially on long descents.

Two common forms are exhaust brakes and compression release brakes. An exhaust brake modifies exhaust flow with a valve to raise back pressure in the exhaust system, increasing engine braking force. A compression release brake, also known as a Jake brake, temporarily opens the exhaust valves at the end of the compression stroke to vent compressed air, converting it into sound and creating a braking torque. Modern engine-management systems can combine electronic control to optimize braking, fuel use, and engine protection.

Usage: Engine brakes are most common on heavy-duty diesel trucks and buses, though some passenger vehicles employ engine-braking features integrated into diesels or hybrids. They are typically engaged via a switch or throttle pedal and are used during deceleration, downhill driving, and when wheel brakes would overheat.

Advantages: They reduce brake wear and overheating, improve control on descents, and can provide reliable deceleration without relying solely on wheel brakes.

Limitations and drawbacks: Performance varies with engine speed and gear; exhaust brakes can generate significant noise; compression-release brakes can be loud and may introduce harsher engine braking; some regions regulate noise levels; may increase fuel consumption in certain conditions.

Regulation and environmental notes: Noise regulations for engine brakes vary by country and region; some urban areas restrict use during certain hours.

History: The concept emerged in the mid-20th century with the development of compression-release and later exhaust brakes, widely adopted in heavy trucks; Jacobs Vehicle Systems popularized the Jake brake.