Skip to main content

Engine management system and ADAS

Short answer

EMS controls fuel injection, ignition timing, idle speed, and emissions via sensor inputs and ECU maps. ADAS uses radar, cameras, ultrasonic sensors. Adaptive cruise control maintains gap via radar; lane departure warning uses camera; autonomous emergency braking detects obstacles and applies full braking automatically.

(a) Describe the functions of an engine management system (EMS) in a petrol engine. (b) What is ADAS? Explain adaptive cruise control, lane departure warning, and autonomous emergency braking, and the sensors used.

(a) Engine management system (EMS)

The EMS is the combined electronic control of fuel, ignition and auxiliary systems by one ECU.

 Sensors (air, throttle, temp, crank, O2, knock)
          |
        [ECU]
   |      |        |         |
 Fuel   Ignition  Idle     EGR/EVAP/
 injection timing speed    VVT

Functions

  1. Fuel control: calculates the basic injection time from air mass and speed, and corrects for temperature, battery voltage and lambda feedback (closed loop at 14.7:1).
  2. Ignition control: sets spark timing from speed, load and knock sensor (retards the spark upon knock).
  3. Idle speed control with electronic throttle.
  4. Emission control: EGR, purge, secondary air, catalyst monitoring (OBD).
  5. Others: fuel cut-off in overrun, cooling fan control, variable valve timing, self-diagnosis and limp-home mode.

(b) ADAS - Advanced Driver Assistance Systems

ADAS uses sensors and software to help the driver and increase safety. Sensors are radar (77 GHz, distance and speed), camera (lane, signs), ultrasonic (parking) and lidar.

SystemWorking
Adaptive cruise control (ACC)Front radar measures the gap to the car ahead; ECU controls throttle and brakes to keep a set time gap
Lane departure warning / keep assistCamera sees lane markings; warns by vibration or steers back if the car drifts without indicator
Autonomous emergency braking (AEB)Radar/camera predicts collision; warns, then applies full braking if the driver does not react

Other: blind-spot detection, parking assist, traffic sign recognition, driver drowsiness alert.

✓ Answer checked by Claude Opus 5.5 (high effort)

Related questions

All Automotive Technology chapter 11 questions →