Practice Test GeeksUK Driver CPC Practice Test
← All CPC Flashcard Decks

Vehicle Systems Flashcards

6 cards from real CPC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 6 Vehicle Systems flashcards as text

  1. What is the function of the turbocharger in a modern HGV diesel engine?

    Answer: To force more air into the engine cylinders, increasing power output and efficiency

    A turbocharger uses exhaust gas energy to spin a turbine that compresses intake air, forcing more air (and therefore more fuel) into the combustion chambers. This increases power output without increasing engine size, also improving fuel efficiency.

  2. What is the purpose of the EGR (Exhaust Gas Recirculation) system?

    Answer: To reduce nitrogen oxide (NOx) emissions by recirculating a portion of exhaust gas back into the engine

    The EGR system reduces NOx emissions by recirculating a controlled amount of exhaust gas back into the intake manifold. This lowers combustion temperatures, which reduces the formation of nitrogen oxides, a major pollutant.

  3. What type of braking system do most modern HGVs use?

    Answer: Air-operated (pneumatic) disc or drum brakes

    Most modern HGVs use air-operated (pneumatic) braking systems with disc or drum brakes. Compressed air operates the brake chambers, which push the brake pads against the disc or drums against the shoes. Air brakes are preferred because they are fail-safe.

  4. What is the function of the air compressor in an HGV?

    Answer: To generate compressed air for the braking system, suspension, and other pneumatic systems

    The engine-driven air compressor generates compressed air that is stored in air tanks and used to operate the brakes, air suspension, and other pneumatic systems. Maintaining correct air pressure is critical for brake safety.

  5. What does the ABS (Anti-lock Braking System) do on an HGV?

    Answer: It prevents the wheels from locking during heavy braking, allowing the driver to maintain steering control

    ABS prevents wheel lock-up during heavy braking by rapidly modulating brake pressure to individual wheels. This maintains tyre grip and allows the driver to continue steering the vehicle while braking, reducing the risk of jackknifing and skidding.

  6. What is the purpose of the differential in an HGV drivetrain?

    Answer: To allow the driven wheels to rotate at different speeds when cornering

    The differential allows the driven wheels on the same axle to rotate at different speeds during cornering. The outer wheel travels a greater distance than the inner wheel, so must rotate faster. Without a differential, the tyres would scrub and handling would be dangerous.