Modern Vehicle Technology and Environmental Aspects
This final domain covers current Indian emission law, the technologies that meet it, electric and hybrid vehicles, and end-of-life issues. Expect Bharat Stage norms, after-treatment devices, alternative fuels, hybrid and EV architecture, ADAS features and recycling.
Emissions and after-treatment
- Bharat Stage VI took effect on 1 April 2020, skipping BS-V. Fuel sulphur fell from 50 ppm to 10 ppm.
- Petrol: a three-way catalytic converter controls CO, HC and NOx; it needs stoichiometric running and a lambda sensor.
- Diesel: DOC plus DPF for particulates, EGR to cut NOx inside the cylinder, SCR with AdBlue (32.5 percent urea) for NOx in the exhaust. AdBlue has its own tank and is dosed into the exhaust, never into fuel or oil.
- OBD-II monitoring of emission-related faults is mandatory.
Cleaner and electrified vehicles
- Alternative fuels: CNG and LPG, ethanol blending up to E20, biodiesel, hydrogen fuel cells.
- Hybrids: HEV (no plug), PHEV (plug-in), mild hybrid with a belt starter-generator; regenerative braking recovers kinetic energy.
- BEV: battery pack, motor, inverter, charger, battery management system. No tailpipe emissions, but the grid mix and battery recycling decide the real benefit.
- ADAS: ABS, EBD, ESC, TPMS, airbags, reversing camera, lane assist, autonomous emergency braking.
- End of life: scrappage policy, depollution, ELV recycling, second-life and safe disposal of lithium batteries.
Worked example
A BS-IV light diesel vehicle had a NOx limit of 0.25 g/km; BS-VI reduced it to 0.08 g/km. Reduction = (0.25 - 0.08) / 0.25 x 100 = 68 percent. Reasoning: the percentage is measured against the older limit, so a 68 percent cut forced most diesel cars to adopt EGR plus SCR, which is why AdBlue tanks appeared.
Traps that cost marks
Calling AdBlue a fuel additive. Claiming an EV is zero-emission over its whole life. Believing regenerative braking replaces friction brakes entirely. Mixing up BS-IV (50 ppm sulphur) and BS-VI (10 ppm) fuel limits.