--- title: "Engine management system and ADAS" subject: "Automotive Technology" chapter: 11 key: "semester_5/automotive_technology:engine-management-and-adas" source: https://www.bctengineer.com/q/semester_5/automotive_technology/engine-management-and-adas site: BCT Engineering --- # Engine management system and ADAS Automotive Technology · Chapter 11: Automotive Electronics - Asked in: year not given, 4+4 marks - Video: [Advanced Driver Assistance System | ADAS System in Car | Explained](https://www.youtube.com/watch?v=V_gPUh2xb7E) — Motoring Masters - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_5/automotive_technology/engine-management-and-adas - Whole chapter: https://www.bctengineer.com/md/semester_5/automotive_technology/chapter-11 ## Question (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. ## 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. ## Answer #### (a) Engine management system (EMS) The EMS is the combined electronic control of fuel, ignition and auxiliary systems by one ECU. ```text 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**. | System | Working | |---|---| | 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 assist | Camera 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. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. How does the EMS calculate basic injection time? A. From the tyre pressure B. From air mass and engine speed, then corrected for temperature, voltage and lambda C. From the fuel gauge D. Fixed value Answer: B. Corrections include closed loop lambda feedback at 14.7:1. (Key point: Fuel control) 2. What does the EMS do on knock? A. Stops injection permanently B. Retards the spark timing C. Advances the spark D. Opens EGR fully Answer: B. The knock sensor tells the ECU to retard timing. (Key point: Knock) 3. How does adaptive cruise control work? A. Camera steers back to the lane B. Lidar only C. Front radar measures the gap and the ECU controls throttle and brakes to keep a set time gap D. Ultrasonic sensors park the car Answer: C. ACC uses 77 GHz radar for distance and speed. (Key point: ACC) 4. What does AEB do? A. Accelerates B. Only warns C. Predicts a collision, warns, then applies full braking if the driver does not react D. Steers away Answer: C. Radar/camera detect the risk; braking is applied automatically if needed. (Key point: AEB) ## Related in Automotive Technology - [Sensors, actuators and ECU](https://www.bctengineer.com/question.md?key=semester_5%2Fautomotive_technology%3Asensors-actuators-ecu) — Automotive Technology, chapter 11 - [Anti-lock braking system and EBD](https://www.bctengineer.com/question.md?key=semester_5%2Fautomotive_technology%3Aabs-and-ebd-systems) — Automotive Technology, chapter 7 - [Engine displacement, compression ratio and power](https://www.bctengineer.com/question.md?key=semester_5%2Fautomotive_technology%3Aengine-displacement-bmep-numerical) — Automotive Technology, chapter 1 - [Air flow and fuel flow of an SI engine](https://www.bctengineer.com/question.md?key=semester_5%2Fautomotive_technology%3Afuel-consumption-air-flow-numerical) — Automotive Technology, chapter 2 - [Engine lubrication systems and SAE grades](https://www.bctengineer.com/question.md?key=semester_5%2Fautomotive_technology%3Alubrication-systems-and-oil-grades) — Automotive Technology, chapter 4 - [Battery ignition system and spark timing calculation](https://www.bctengineer.com/question.md?key=semester_5%2Fautomotive_technology%3Abattery-ignition-spark-numerical) — Automotive Technology, chapter 3 ## Related in other subjects - [IP, BP and efficiencies of a petrol engine](https://www.bctengineer.com/question.md?key=semester_6%2Finternal_combustion_engines%3Aindicated-brake-power-efficiency-numerical) — Internal Combustion Engines, chapter 8 - [Open-loop cruise control using P control](https://www.bctengineer.com/question.md?key=semester_6%2Fembedded_system%3Aopen-loop-cruise-p-control) — Embedded System, chapter 7 - [Autonomous vs distributed system](https://www.bctengineer.com/question.md?key=semester_7%2Fdistributed_system%3Aautonomous-vs-distributed) — Distributed System, chapter 1 - [Emergency power supply system for industry](https://www.bctengineer.com/question.md?key=semester_6%2Findustrial_power_distribution_and_illumination%3Aemergency-supply-system-industry) — Industrial Power Distribution and Illumination, chapter 9, asked 2×