190204d Emissions Control/After Treatment System Flashcards
API stands for
American Petroleum Institue
Conducts research and verifes info for petroleum industry
What does EPA stand for?
Environmental Protection Agency
Sets emission standards for hydrocarbon powered engines
In 2002 EGR regulations mandated ___ reduction in the ________ of ______
50%
NOx oxides of nitrogen
The combinations of using EGR and retarted injection timing to reduce NOx in a loss of what?
Loss of power and reduced fuel economy.
A negative effects of EGR is that it causes an in crease of CO and HC this requires additional after treatment usallu in the form of?
DOC
Diesel oxidation catalist
What are 2 types basic types of EGR valves
Butterfly and poppet
The regulatory body that sets emission levels for North American diesel engines is
The EPA. Environmental protection agency
Initial EPA Tier 4 emissions were introduced for off-road equipment engines in what year
2011
To be compliant with EPA 2007 emission regulations, a highway tractor must be equipped with an EGR system and a
DPF
In the EGR system, the VDT is controlled by the ECM to vary
Exhaust back pressure
With the EGR system, introducing exhaust gas into the intake manifold is done to reduce the engines
Combustion pressure and temperature
The cooling system on an engine equipped with the EGR system has a greater heat loading because of
Exhaust gases must pass through a water cooled heat exchanger
To obtain EGR flow, the VGT turbocharger nozzle vanes would have to be
Partially closed
A particulate trap is used to remove what emissions from a diesel engines exhaust
Soot
The DOC in the exhaust aftertreatment module reacts with injected hydrocarbons to do what
Create additional heat for DPF regeneration
To monitor operation of the exhaust aftertreatment module on a DPF equipped diesel engine, there are temperature sensors at.
The DOC Inlet, DOC outlet and DPF outlet
If the yellow DPF lamp is illuminated solid the operator should
Increase the duty cycle and load on the engine
If the suit loading on a DPF rises above 80% the engine will
Undergo a severe De-rate and shut down
To prevent damage to the filter core. a diesel engine equipped with a DPF must use
ULSD ultra low sulfur diesel
A plugged DPF or DOC can cause
Excessive exhaust system back pressure
If a dosing valve is used on an engine equipped with a DPF. The purpose of this dosing valve is to supply what
Hydrocarbons to react with the DOC
During regeneration, the DPF converts spot emissions to harmless compounds of what
CO2 and NO
How do you remove the trapped ash from the DPF
With an off vehicle cleaning process at periodic intervals
During a regeneration cycle, the outlet exhaust temperature of the DPF system will reach
593°C or 1100°F
The ECM determines when the soot level in the DPF is excessive by monitoring what signal
The differential pressure sensor signal
On a DPF system, the HEST lamp is usually illuminated when.
During a regeneration cycle
That SCR system is primarily used to reduce emissions of what
NOx
a DPF soot loading level of 60% is indicated by what
A moderate engine de-rate and a flashing yellow DPF lamp
DEF is sprayed in before the catalytic converter on an SCR system where it mixes with the hot exhaust gases and is converted into
Ammonia and CO2
After the ammonia and exhaust gases pass through the SCR catalytic converter, the NOx emissions are converted to
Nitrogen and water vapor
The industry standard for DEF is a solution of
32.5% urea and 67.5% distilled water
How much carbon is in smog after the combustion process
40%
What is opacity
The degree in which smoke blocks light
Active regeneration requires what to be injected into the exhaust stream ?
Hydrocarbons (deisel fuel)
If the fluid level in the SCR reservoir gets below the minimum level, the ECM will warn the operator and
De-rate the engine
The SCR metering module sends a specific quantity of DEF to the dosing module based on
Engine load and exhaust temperature
2007 on highway truck engine must use oil that meets API ________ ? specifications to be compatible with the exhaust aftertreatment devices
CJ4
When following manufacture specs, what mods are allowed on the exhaust system on a system with an SCR
Tailpipe modifications
Besides “cow farts” what are some emissions related to greenhouse gasses
N0x , C0, and C02.
The EGR valve controls the gas flow to the cooler by opening up the butterfly valve which is positioned by
An air operated actuator
TQ. During active regen what do the hydro carbons react with in the doc to produce heat ?
They react with the catalysts in the doc core (exhaust gas outlet temps will reach 593 C (1100 F)
TQ. Active regeneration can be initiated 3 ways, what are they ?
ECM , DPF dash switch ,
Engine manufacturer’s diagnostic program or electronic service tool
What controls the Dosing Valve during regeneration process ?
ECM
How many temperature sensors do the DOC and DPF have ?
Three (DOC inlet and outlet/DPF inlet) (DPF outlet)
How many pressure sensors does the DPF have ?
Two (inlet and outlet)
The combination of using EGR and retarded injection timing to reduce NOx would result in
Loss of power and reduced fuel economy
TQ. What events occur when DPF soot loading reaches 80% ?
DPF light flashing, check engine light comes on and begins to de-rate engine. The DPF is at Maximum capacity. Operator must park unit and force regeneration with dash switch.
Diesel engines create particulate matter. 3 main sources are ?
Unburnt fuel
ash from diesel fuel
soluble organic fractions (sof)
