Tag Archives: vehicle emissions

What is an exhaust emissions system?

August 19, 2025 Alex Leave a comment

An exhaust emissions system includes catalytic converters, oxygen sensors, EGR valves, PCV systems, and evaporative emission controls that reduce pollutants by 95-99%. Modern systems use three-way catalysts, SCR technology, and DPF filters to convert harmful gases into harmless compounds while monitoring air-fuel ratios.

Exhaust Emissions

Measuring vehicle exhaust emissions

August 19, 2025 Alex Leave a comment

Vehicle emission measurement uses gas analyzers with infrared and electrochemical sensors for real-time pollutant detection. Laboratory testing follows standardized cycles like NEDC or WLTP over dynamometers. Portable Emission Measurement Systems (PEMS) enable real-world testing. Measurements include mass flow rates, concentrations in ppm or mg/km, and conversion efficiency calculations for emission control systems.

Exhaust Emissions

Petrol (gasoline) exhaust emissions?

August 19, 2025 Alex Leave a comment

Gasoline engines primarily emit carbon monoxide (CO) at 0.5-5%, nitrogen oxides (NOx) at 100-1000 ppm, and unburned hydrocarbons (HC) at 100-1000 ppm. They produce less particulate matter than diesel but generate more carbon monoxide. Three-way catalytic converters reduce these emissions by 90-95% when operating at optimal air-fuel ratios.

Exhaust Emissions

Remote sensing of vehicle exhaust emissions

August 19, 2025 Alex Leave a comment

Remote sensing uses infrared and ultraviolet light beams across roadways to measure exhaust concentrations as vehicles pass. Systems detect CO, HC, and NOx in 0.5 seconds without stopping traffic. Accuracy reaches 95% for identifying high-emitting vehicles. Over 200 cities worldwide use remote sensing for emission compliance monitoring and targeting vehicles for inspection programs.

Exhaust Emissions

MOT exhaust emissions test results explained

August 19, 2025 Alex Leave a comment

MOT emission results show CO percentage, HC in parts per million, and diesel opacity in m⁻¹. Petrol limits: CO under 3.5% (pre-2002) or 0.5% (post-2002), HC under 1200 ppm (pre-2002) or 200 ppm (post-2002). Diesel limits: opacity under 2.5 m⁻¹ (naturally aspirated) or 3.0 m⁻¹ (turbocharged). Lambda values between 0.97-1.03 indicate proper air-fuel mixture.

Exhaust Emissions

How to improve or reduce exhaust emissions?

August 19, 2025 Alex Leave a comment

Improve emissions through regular maintenance: replace oxygen sensors every 60,000-100,000 miles, change air filters every 15,000 miles, use quality fuel with detergent additives, and address check engine lights immediately. Drive efficiently with gentle acceleration and maintain proper tire pressure. Proper maintenance achieves 95% emission reduction.

Exhaust Emissions

How to fix exhaust emissions?

August 19, 2025 Alex Leave a comment

Fix emissions by diagnosing root causes through OBD-II scanning, replacing faulty oxygen sensors (£50-150), cleaning or replacing catalytic converters (£200-1,500), repairing vacuum leaks, and updating engine software. Address fuel system problems, ignition misfires, and air intake restrictions. Professional diagnosis costs £50-100 but prevents unnecessary repairs.

Exhaust Emissions

Exhaust emissions test

August 19, 2025 Alex Leave a comment

Exhaust emissions tests measure pollutant concentrations using gas analyzers during standardized driving cycles. Tests include CO, HC, NOx, and opacity measurements at idle and 2500 RPM. Modern tests use 5-gas analyzers measuring CO2 and O2 for air-fuel ratio analysis. Testing occurs during MOT, NCT, or annual inspections with specific pass/fail limits.

Exhaust Emissions

How to check exhaust emissions?

August 19, 2025 Alex Leave a comment

Check exhaust emissions using a 5-gas analyzer connected to the tailpipe during engine warm-up. Measure CO, HC, NOx, CO2, and O2 at idle and 2500 RPM for 30 seconds each. Compare readings to legal limits: CO under 0.5%, HC under 200 ppm for modern vehicles. Professional testing costs £25-50 while basic OBD scanners provide preliminary checks.

Exhaust Emissions

Exhaust emissions tester / gas analyzer

August 19, 2025 Alex Leave a comment

Professional gas analyzers use infrared sensors for CO and CO2, flame ionization detectors for HC, electrochemical cells for NOx and O2. 5-gas analyzers cost £3,000-15,000 with annual calibration requirements. Portable units offer basic CO/HC measurement for £200-500. Modern analyzers include automatic temperature compensation, data logging, and pass/fail determination based on programmed emission limits.

Exhaust Emissions

Exhaust emissions repair cost

August 19, 2025 Alex Leave a comment

Emission repair costs range from £20 (air filter) to £2,000+ (complete system replacement). Common repairs: oxygen sensors £50-150, catalytic converters £200-1,500, EGR valves £150-400, DPF cleaning £100-300. Professional diagnosis (£50-100) prevents unnecessary work. Preventive maintenance costs 70% less than reactive repairs and maintains warranty coverage.

Exhaust Emissions

Exhaust emissions system cleaner

August 19, 2025 Alex Leave a comment

System cleaners remove carbon deposits, improve catalyst efficiency, and restore sensor function. Use every 3,000-5,000 miles or before emission testing. Quality cleaners can improve emission performance by 10-20% and extend component life. Professional cleaning services cost £50-150 while DIY products range from £10-30 per treatment.

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