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Nitrogen Oxide or NO is created when an engine’s combustion chamber temperature reaches over 2500F.
What causes high no?
High NOx emissions can occur when an engine’s air-fuel mixture is too lean. This could be caused by a problem with the vehicle’s oxygen sensor, malfunctioning air flow and coolant sensors or a leak in the fuel system.
How do I reduce NOx emissions for a smog check?
NOx Emission Reduction Strategies by Marc Karell and Amit Chattopadhyay. Fuel switching. Fuel switching is the simplest and potentially the most economical way to reduce NOx emissions. Flue-gas recirculation (FGR). Low NOx burners. Derating. Steam or water injection. Staged combustion. Fuel reburning.
How can I lower my HC ppm emissions?
On a precomputer carbureted car, one way to get under the HC and CO limits is to retard the ignition timing. This will slow the idle and provide a longer, hotter burn. Then, bring the idle speed back up to specs with the throttle stop screw or idle stop solenoid, which will admit more air.
How do you fix high NOx emissions?
The solution to this problem is called De-Carbonizing. It usually costs around two labor hours at a smog check repair station. It will remove a good amount of carbon out of an engine. This will increase combustion space, lower compression and lower NOx.
What is HC ppm in the smog test?
Find “HC PPM” within the tailpipe section. You read this as hydrocarbon parts per million, and it means the number of hydrocarbon molecules for every million molecules emitted through the exhaust.
What causes high HC readings on emissions test?
What causes high HC emissions? Excessive HC results from ignition misfire or misfire due to excessively lean or rich air/fuel mixtures.
Does NOx cause smog?
Nitrogen oxides (NOx) react to form smog and acid rain. NOx reacts with ammonia, moisture and other compounds to form nitric acid vapour and related particles. The impacts of NOx on human health include damage to the lung tissue, breathing and respiratory problems.
Can bad spark plugs cause high NOx?
If the base timing is advanced too far, the spark plug will ignite the air fuel mixture early, causing the combustion temperature to rise as the compression stroke continues, causing NOx to form.
How can I pass smog illegally?
6 Proven Methods for Passing an Emissions (Smog) Test: Test a very warm car on a cool day. Use a specialized fuel additive. Inflate tires to the proper (high) level. Perform an oil change. Turn off your “Check Engine” light (if needed). Find a shop that offers a free retest.
What causes high HC at idle?
High HC (and not CO) indicates that it is misfiring at idle. A common cause is a vacuum leak resulting in a lean mixture that is unable to ignite and a rough idle.
What does high HC ppm mean?
A high HC reading means the test found high HC (hydrocarbons) in your emissions. In other words, too much gas is left in the exhaust after combustion.
Does Old gas affect emissions?
The last major area where old gas becomes a problem is within the engine cylinders. Excessive carbon buildup may cause the check engine light to come on due increased emissions, poor idling, and difficulting starting your engine.
What does NOx ppm mean?
The primary nitrogen pollutants produced by combustion are nitric oxide (NO) and nitrogen dioxide (NO2) and are generally referred to collectively as NOx. Instruments which measure NOx generally read in Parts Per Million (PPM).
What is NOx ppm?
NOx is considered one of the critical pollutants found in emissions from all types of internal combustion engines. Concentrations of NOx in untreated diesel exhaust are typically between 50 and 1000 ppm. If concentrations are given in mass units, NOx is usually expressed as NO2 equivalent.
Does a catalytic converter reduce NOx?
Three-Way Plus Air Catalytic Converters The front, coated with the precious metal rhodium, is used to reduce NOx emissions into simple N2 and O2. This process is most effective when little O2 is present (rich mixture).
How do you read a smog test?
How to Read Smog Test Results Review the testing procedure. Using California as an example, vehicles are run through each test at two different speeds. Read the first line of the emissions test results. Read the results in each emissions category. Read and follow any of the maintenance notes included in the report.
What would a high HC low CO and high O2 at the same indicate?
High HC, low CO, and high O2 at the same time indicates a misfire due to a lean or EGR diluted mixture. Normal to marginally high HC, normal to marginally low CO, and high O2 indicates a misfire due to false air or marginally lean mixture.
Which gas is generally considered to be the rich indicator?
Carbon Monoxide (CO) Is partially burned fuel known as a rich indicator. CO is a highly poisonous and displaces oxygen in the bloodstream. Oxides of nitrogen (NOX) Is an unnatural combination of oxygen and nitrogen that occurs when combustion temperatures are 2500 degrees or higher.
What causes emissions to fail?
A rich air/fuel mixture will often cause a failed emissions test. This problem is usually a result of a defective oxygen sensor or faulty injectors. So, if you fail emissions, have these components inspected and changed if necessary. You have a loose or leaking gas cap.
What is HC in gas?
Hydrocarbons. Hydrocarbon (HC) are also known as green or natural gases. The two major representatives are propane and ethane (known as R290 and R170).
