Vehicle emissions inspection station

Automobile emissions control covers all the technologies that are employed to reduce the air pollution-causing emissions produced by automobiles. Exhaust emissions control systems were first required on 1966 model year vehicles produced for sale in the state of California, followed by the United States as a whole in model year 1968. the overall reduction in pollution has been much slower. The emissions produced by a vehicle fall into three basic categories: Image File history File linksMetadata Download high-resolution version (2304x1728, 663 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Automobile emissions control Vehicle inspection Metadata This file contains additional information, probably added from the digital camera or... Image File history File linksMetadata Download high-resolution version (2304x1728, 663 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Automobile emissions control Vehicle inspection Metadata This file contains additional information, probably added from the digital camera or... Air pollution is the modification of the natural characteristics of the atmosphere by a chemical, particulate matter, or biological agent. ... Car redirects here. ... This article is about the U.S. state. ...

1. Tailpipe emissions: This is what most people think of when they think of vehicle air pollution; the products of burning fuel in the vehicle's engine, emitted from the vehicle's exhaust system. The major pollutants emitted include:
   1. Hydrocarbons: this class is made up of unburned or partially burned fuel, and is a major contributor to urban smog, as well as being toxic. They can cause liver damage and even cancer.
   2. Nitrogen oxides (NOx): These are generated when nitrogen in the air reacts with oxygen under the high temperature and pressure conditions inside the engine. NOx emissions contribute to both smog and acid rain.
   3. Carbon monoxide (CO): a product of incomplete combustion, carbon monoxide reduces the blood's ability to carry oxygen and is dangerous to people with heart disease.
   4. Carbon dioxide (CO₂): Emissions of carbon dioxide are an increasing concern as its role in global warming as a greenhouse gas has become more apparent.

An exhaust pipe is usually a pipe used to guide waste exhaust gases away from a controlled combustion inside an engine or stove. ... A colorized automobile engine The internal combustion engine is an engine in which the combustion of fuel and an oxidizer (typically air) occurs in a confined space called a combustion chamber. ... In chemistry, a hydrocarbon is a cleaning solution consisting only of carbon (C) and hydrogen (H). ... For other uses, see Smog (disambiguation). ... The term nitrogen oxide is a general term and can be used to refer to any of these oxides (oxygen compounds) of nitrogen, or to a mixture of them: Nitric oxide (NO), nitrogen(II) oxide Nitrogen dioxide (NO2) Dinitrogen monoxide (N2O) (Nitrous oxide) Dinitrogen trioxide (N2O3) Dinitrogen tetroxide (N2O4) Dinitrogen... Look up nox, Nox in Wiktionary, the free dictionary. ... General Name, symbol, number nitrogen, N, 7 Chemical series nonmetals Group, period, block 15, 2, p Appearance colorless gas Standard atomic weight 14. ... The term acid rain is commonly used to mean the deposition of acidic components in rain, snow, fog, dew, or dry particles. ... Carbon monoxide, with the chemical formula CO, is a colorless, odorless, and tasteless gas. ... Carbon dioxide (chemical formula: ) is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ...

Tailpipe emissions control

Dual exhaust pipes attached to a car's muffler

Tailpipe emissions control can be categorised into three parts: Image File history File linksMetadata Download high-resolution version (3008x2000, 2318 KB) Author: Myself (User:Steevven1) Originally hosted on http://www. ... Image File history File linksMetadata Download high-resolution version (3008x2000, 2318 KB) Author: Myself (User:Steevven1) Originally hosted on http://www. ... This article or section does not cite its references or sources. ... This article is about the engine piece. ...

1. Increasing engine efficiency
2. Increasing vehicle efficiency
3. Cleaning up the emissions

Increasing engine efficiency

Engine efficiency has been gradually improved with progress in following technologies:

• Electronic ignition
• Fuel injection systems
• Electronic control unit

The ignition system of an internal-combustion engine is an important part of the overall engine system that provides for the timely burning of the fuel mixture within the engine. ... // Fuel injection is a system of fuel delivery for mixture with air in an internal combustion engine. ... In automotive electronics, an electronic control unit (ECU) is an embedded microcomputer that controls one or more of the electrical subsystems in a vehicle. ...

Increasing vehicle efficiency

Contributions to the goal of reducing fuel consumption and related emissions come from

• lightweight vehicle design
• minimized air resistance
• reduced rolling resistance
• improved powertrain efficiency
• increasing spark to the spark plug (this topic should be under the ignition system)
• regenerative braking

Each of these items breaks down into a number of factors.

Increasing driving efficiency

Significant reduction of emissions come from

• driving technique (some 10-30% reduction)
• unobstructed traffic conditions
• cruising at an optimum speed for the vehicle
• reducing the number of cold starts

Cleaning up the emissions

Advances in engine and vehicle technology continually reduce the amount of pollutants generated, but this is generally considered insufficient to meet emissions goals. Therefore, technologies to react with and clean up the remaining emissions have long been an essential part of emissions control.

Air injection

A very early emissions control system, the Air injection reactor (AIR) reduces the products of incomplete combustion (hydrocarbons and carbon monoxide) by injecting fresh air into the exhaust manifolds of the engine. In the presence of this oxygen-laden air, further combustion occurs in the manifold and exhaust pipe. Generally the air is delivered through an engine-driven 'smog pump' and air tubing to the manifolds. A very early automobile emissions control system, the Air injection reactor (AIR) reduces the products of incomplete combustion (hydrocarbons and carbon monoxide) by injecting fresh air into the exhaust manifolds of the engine near to the exhaust valves. ... In automotive engineering, an intake manifold or inlet manifold is a part of an engine that supplies the fuel/air mixture to the cylinders. ... An exhaust pipe is usually a pipe used to guide waste exhaust gases away from a controlled combustion inside an engine or stove. ...

Exhaust Gas Recirculation

Many engines produced after the 1973 model year have an exhaust gas recirculation valve between the exhaust and intake manifolds; its sole purpose is to reduce NOx emissions by introducing exhaust gases into the air/fuel mixture, lowering peak combustion temperatures.

Catalytic converters

The catalytic converter is a device, placed in the exhaust pipe, which converts various emissions into less harmful ones using, generally, a combination of platinum, palladium and rhodium as catalysts.They make for a significant, and easily applied, method for reducing tailpipe emissions. The lead emissions were highly damaging to human health, and its virtual elimination has been one of the most successful reductions in air pollution. Catalytic converter on a Dodge Ram Van. ...

Evaporative emissions control

Efforts at the reduction of evaporative emissions include the capturing of vented vapors from within the vehicle, and the reduction of refuelling emissions.

Capturing vented vapors

Within the vehicle, vapors from the fuel tank are channelled through canisters containing activated carbon instead of being vented to the atmosphere. These are known as carbon canisters. The vapors are adsorbed within the canister, which feeds into the inlet manifold of the engine. Activated carbon Activated carbon, also called activated charcoal or activated coal, is a general term which covers carbon material mostly derived from charcoal. ... In chemistry, a molecule is adsorbed onto a surface when temporary bonds are formed between the surface and the molecule. ... In automotive engineering, an intake manifold or inlet manifold is a part of an engine that supplies the fuel/air mixture to the cylinders. ...

Emission Testing

In 1966, the first emission test cycle was enacted in the State of California measuring tailpipe emissions in PPM (parts per million). An Emission test cycle is a specified procedure for measuring pollutant emissions of engines. ...

 The Environmental Working Group used California ASM emissions data to create an Auto Asthma Index that rates vehicle models based on emissions of hydrocarbons and nitrogen oxides, the chemicals that create smog.[1] 

Some cities are also using a technology developed by Dr. Stedman,of University of Denver which uses lasers to detect emissions while vehicles pass by on public roads, thus eliminating the need for owners to go to a test center. Stedman's laser detection of exhaust gases is commonly used in metropolitan areas. The Environmental Working Group is a public watchdog group specializing in environmental investigations in the areas of toxins, agricultural subsidies, public lands, and corporate accountability. ... The University of Denver (DU) is an independent, coeducational, four-year university in Denver, Colorado. ...

See also

• Aethalometer
• AP 42 Compilation of Air Pollutant Emission Factors
• Emission standards
• Low carbon economy
• Roadway air dispersion modeling
• Vehicle inspection
• Portable Emissions Measurement System