SUBTITLE B: AIR POLLUTION
CHAPTER II: ENVIRONMENTAL PROTECTION AGENCY
PART 276 PROCEDURES TO BE FOLLOWED IN THE PERFORMANCE OF INSPECTIONS OF MOTOR VEHICLE EMISSIONS
SECTION 276.207 TRANSIENT LOADED MODE EXHAUST EMISSIONS TEST PROCEDURES
Section 276.207 Transient Loaded Mode Exhaust Emissions Test Procedures
a) General Requirements
1) The test shall consist of up to 240 seconds of mass emission measurement using a constant volume sampler while the vehicle is driven through a computer-monitored driving cycle on a dynamometer with inertia weight settings appropriate for the weight of the vehicle. The driving cycle shall include acceleration, deceleration, and idle operating modes as specified in subsection (e)(1) of this Section. The 240-second sequence may be ended earlier using fast pass algorithms.
2) The emission standards and dynamometer inertia and power absorption settings shall be automatically selected for the vehicle being tested based upon the identification and validation of the following, as needed:
A) Vehicle type: LDV, LDT1, LDT2, and others as needed;
B) GVWR;
C) Chassis model year;
D) Make;
E) Model;
F) Number of cylinders;
G) Transmission type;
H) LVW or ALVW; and
I) Engine displacement.
Alternative computerized methods of selecting dynamometer test conditions, such as VIN decoding, may be used.
3) The ambient temperature, absolute humidity, and barometric pressure shall be recorded continuously during the transient test, or as a single set of readings if taken less than 4 minutes prior to the transient driving cycle.
4) If the vehicle is shut off, the vehicle shall be restarted as soon as possible before the test and shall be running for at least 30 seconds prior to the transient driving cycle begins.
5) If a vehicle stalls during a transient test, the test shall be aborted and restarted. If after 3 attempts the test cannot be completed, the vehicle shall be rejected.
b) Pre-inspection and Preparation
1) Initial tests (i.e., those occurring for the first time in a vehicle's scheduled test cycle) shall be performed without repair or adjustment at the inspection facility prior to the test.
2) A test, once initiated, shall be performed in its entirety regardless of intermediate outcomes, except in the case of invalid test conditions or unsafe conditions.
3) Tests involving measurement shall be performed with Agency-approved equipment that is operated in accordance with the procedures contained in 40 CFR 85.2234 (Draft), incorporated by reference in Section 276.104(a) of this Part.
4) All accessories (air conditioning, heat, defogger, radio, automatic traction control if switchable, etc.) shall be turned off (if necessary, by the inspector).
5) The vehicle shall be inspected for exhaust leaks. Audio assessment while blocking exhaust flow or gas measurement of CO2 or other gases shall be acceptable. Vehicles with leaking exhaust systems shall be rejected from testing.
6) Vehicles with missing tailpipe sections that prohibit placement of the exhaust collection system to capture the entire exhaust stream shall be rejected from testing.
7) The vehicle temperature gauge, if equipped and operating, shall be checked to assess temperature. If the temperature gauge indicates that the engine is well below normal operating temperature, the vehicle shall receive a second-chance emission test if it fails the initial test for HC or CO. Vehicles in overheated condition shall be rejected from testing.
8) Vehicles shall be rejected from testing if drive axle tires:
A) exhibit visible cords, belts, bubbles, cuts, or other damage, or
B) are space-saver spare tires, or
C) are not reasonably sized tires.
9) Vehicles' drive axle tires shall be inspected for proper inflation. If one or more of these tires appears low, it shall be inflated to approximately 30 psi, or to tire sidewall pressure, or manufacturer's recommendation.
10) Drive axle tires of vehicles subject to additional testing for the purpose of program evaluation under 40 CFR 51.353, incorporated by reference in Section 276.104(d) of this Part, shall have their tires inflated to tire sidewall pressure.
11) Background concentrations of HC, CO, NOx, and CO2 shall be sampled as specified in 40 CFR 85.2226(b)(2)(iv) (Draft), incorporated by reference in Section 276.104(a) of this Part, to determine background concentration of dilution air. The sample shall be taken for a minimum of 15 seconds within 120 seconds after the start of the transient driving cycle, using the same analyzers used to measure tailpipe emissions. Average readings over the 15 seconds for each gas shall be recorded in the test record. Testing shall be prevented until the average ambient background levels are less than 20 ppmC HC, 35 ppm CO, and 2 ppm NOx (when applicable), or outside ambient air levels (not influenced by station exhaust), whichever are greater.
12) While a lane is in operation, the CVS shall continuously purge the CVS hose between tests. The blower may be turned off if the CVS is not in operation, but the system shall be purged for 2 minutes prior to the start of a test if the blower has been turned off. The off time shall be computer monitored and recorded to a history file for quality assurance.
c) Equipment Positioning and Settings
Vehicle positioning and settings shall be conducted according to the method specified in 40 CFR 85.2221(c) (Draft), incorporated by reference in Section 276.104(a) of this Part, with the following exceptions:
1) the cooling fan need only be activated when the ambient temperature exceeds 72°F;
2) the parking brake should only be activated on front wheel drive vehicles when possible; and
3) the hood will not be opened for cooling purposes.
d) Vehicle Conditioning
1) Queuing Time
When the measured wait time exceeds 20 minutes, the vehicle shall receive a second-chance emission test if the following conditions apply:
A) fails the test; and
B) measured values for HC, CO, and NOx (if applicable) are at or below 1.5 times the applicable standards of 35 Ill. Adm. Code 240.
2) Program Evaluation
Vehicles selected for additional testing for the purpose of program evaluation under 40 CFR 51.353, incorporated by reference in Section 276.104(d) of this Part, shall receive two full transient emission tests of 240 seconds each. Results from both tests and the test order shall be separately recorded in the test record. Emission results shall be provided to the motorist according to the following criteria:
A) If the vehicle passes both tests, then the first test result shall be provided.
B) If the vehicle passes one test and fails the other test, then the test results from the passing test shall be provided.
C) If the vehicle fails both tests, then the test results from the second test shall be provided.
e) Vehicle Emission Test Sequence
1) Transient Driving Cycle
The vehicle shall be driven over the driving cycle contained in Section 276.Table A of this Part.
2) Driving Trace
The inspector shall follow an electronic, visual depiction of the time/speed relationship of the transient driving cycle (hereinafter, the trace). The visual depiction of the trace shall be of sufficient magnification and adequate detail to allow accurate tracking by the driver and shall permit the driver to anticipate upcoming speed changes. The trace shall also clearly indicate gear shifts as specified in subsection (e)(3) of this Section.
3) Shift Schedule
For vehicles with manual transmissions, inspectors shall shift gears according to the following shift schedule:
|
Shift Sequence Gear |
Approximate Speed Miles Per Hour |
Nominal Cycle Time Seconds |
|
|
|
|
|
1-2 |
15 |
9.3 |
|
2-3 |
25 |
47.0 |
|
De-clutch |
15 |
87.9 |
|
1-2 |
15 |
101.6 |
|
2-3 |
25 |
105.5 |
|
3-2 |
17 |
119.0 |
|
2-3 |
25 |
145.8 |
|
3-4 |
40 |
163.6 |
|
4-5 |
45 |
167.0 |
|
5-6 |
50 |
180.0 |
|
De-clutch |
15 |
234.5 |
Gear shifts shall occur at the points in the driving cycle where the specified speeds are obtained. For vehicles with fewer than 6 forward gears, the same schedule shall be followed with shifts above the highest gear disregarded.
4) Speed excursion limits shall apply as follows:
A) The upper limit is 2 mph higher than the highest point on the trace within 1 second of the given time.
B) The lower limit is 2 mph lower than the lowest point on the trace within 1 second of the given time.
C) Speed variations greater than the tolerances (such as may occur during gear changes) are acceptable provided that they occur for no more than 2 seconds on any occasion.
D) Speeds lower than those prescribed during the underpowered intervals of seconds 4 through 18, 97 through 115, and 154 through 219 of the trace will allow the station supervisory personnel the option of overriding the automatic void of the test. As part of the override, the station supervisory personnel will be required to witness a second trace.
i) During the station supervisory personnel's witness of the second or subsequent trace, the test will be aborted if a speed variation exists for more than two seconds on any occasion outside the underpowered intervals. If this condition is detected, the test shall be stopped, and may be restarted, or aborted and rejected.
ii) If a speed lower than those prescribed during the underpowered intervals is detected, the vehicle will have the opportunity to regain the test trace speed. Once the test trace speed is attained, the vehicle will be required to meet the speed excursion limitations for the entirety of the trace, outside the underpowered intervals.
iii) Station supervisory personnel overrides can be used to accept the results of the witnessed second or subsequent trace(s) if the override is flagged with a trace statistic or distance error so long as it meets the requirements specified in subsections (e)(4)(D)(i) and (e)(4)(D)(ii).
E) The test shall be aborted and immediately restarted if speed excursion limits are exceeded, except as described in subsection (e)(4)(D) of this Section.
5) Speed Variation Limits
The speed variation limits shall be determined by one of the following methods:
A) Linear Regression Method
i) A linear regression of feedback value on reference value shall be performed on each transient driving cycle for each speed using the method of least squares, with the best fit equation having the form: y = mx + b, where:
|
y |
= |
The feedback (actual) value of speed |
|
m |
= |
The slope of the regression line |
|
x |
= |
The reference value |
|
b |
= |
The y-intercept of the regression line |
ii) The SE of y on x shall be calculated for each regression line. A transient driving cycle lasting the full 240 seconds that exceeds the following criteria shall be void and the test shall be repeated:
|
SE |
= |
2.0 mph maximum |
|
m |
= |
0.96 - 1.01 |
|
r2 |
= |
0.97 minimum |
|
b |
= |
2.0 mph |
iii) A transient driving cycle that ends before the full 240 seconds that exceeds the following criteria shall be void and the test shall be repeated:
|
SE |
= |
(Reserved) |
|
m |
= |
(Reserved) |
|
r2 |
= |
(Reserved) |
|
b |
= |
(Reserved) |
B) Positive Kinetic Energy (PKE) Method
i) The speed variation limits shall be determined by the following equation for Positive Kinetic Energy (PKE):
|
PKE |
= |
N |
/ |
x |
x |
dx |
|
Σ PPt |
INT |
|||||
|
t=0 |
0 |
|
where: |
|
|
|
|
|
PPt |
= |
V2t - V2t-1 mi2/hr2 for Vt > Vt-1 |
|
|
PPt |
= |
0 for Vt ≤ 0 |
|
|
x |
= |
distance (miles) |
|
|
PPt |
= |
Positive Specific Power at time t |
|
|
Vt |
= |
Velocity at time t |
|
|
Vt-1 |
= |
Velocity at time t-1 |
ii) A transient driving cycle lasting the full 240 seconds with a PKE value that is below the lower PKE limit for passing vehicles or above the upper limit for failing vehicles shall be void and the test shall be repeated:
Upper Limit: PKE > 3456 mi/hr2
Lower Limit: PKE < 3082 mi/hr2
iii) A transient driving cycle that ends before the full 240 seconds with a PKE value that is below the lower second-by-second PKE limit for passing vehicles or above the upper second-by-second PKE limit for failing vehicles shall be void and the test shall be repeated. The second-by-second upper and lower PKE limits are specified in Section 276.Table B.
iv) PKE values shall not be used to make early pass/fail determination.
6) The actual distance traveled for the transient driving cycle shall be measured. If the absolute difference between the measured distance and the theoretical distance for the actual test exceeds 0.05 miles, the test shall be void and shall be repeated.
7) The vehicle shall be rejected if, during the course of the transient loaded mode test, station supervisory personnel verify that the test cannot be completed due to the mechanical condition of the vehicle.
8) Inertia Weight Selection
Operation of the inertia weight selected for the vehicle shall be verified as specified in Section 276.506(a) of this Part. For systems employing electrical inertia simulation, an algorithm identifying the actual inertia force applied during the transient driving cycle shall be used to determined proper inertia simulation.
9) The CVS operation shall be verified for each test for a CFV-type CVS by measuring either the absolute pressure difference across the venturi or measuring the blower vacuum behind the venturi for minimum levels needed to maintain choke flow for the venturi design. The operation of an SSV-type CVS shall be verified throughout the test by monitoring the difference in pressure between upstream and throat pressure. The minimum values shall be determined from system calibrations. Monitored pressure differences below the minimum values shall void the test, and a test lane system lockout shall be initiated. No further testing shall be done until the problem is corrected by station supervisory personnel. At Official Inspection Stations, the vehicle involved shall be immediately retested in a properly operating lane.
f) Transient Loaded Mode Exhaust Gas Test Score Calculations
The transient loaded mode exhaust gas test score shall be determined according to the method specified in 40 CFR 85.2205(b) (Draft), incorporated by reference in Section 276.104(a) of this Part, with the following exceptions:
1) The Phase 2 scores for the test shall be determined by dividing the sum of the mass of each pollutant obtained in each second of the Phase 2 test by the number of miles driven in the Phase 2 test. The first data point is the sample taken from t=94 to t=95. The Phase 2 test score shall be determined by the following equation:
|
Phase 2 gpm |
= |
s |
|
|
Σ |
grams of emissions |
||
|
t=94 |
|
||
|
|
|
s |
|
|
Σ |
miles traveled |
||
|
t=94 |
|
Where s = duration of test in seconds for fast pass, or
s = 239 seconds for complete transient loaded mode exhaust gas test.
2) NOxe = nitrogen oxide concentration of the dilute exhaust sample as
measured in ppm and multiplied by 1.03.
3) NOxd = background nitrogen oxide concentration of the dilution air,
sampled as described in 40 CFR 85.2221(b)(5) (Draft), incorporated by reference in Section 276.104(a) of this Part, as measured in ppm and multiplied by 1.03.
g) Pass/Fail Determination
Compliance with the transient loaded mode exhaust emission test shall be made in accordance with the standards contained in 35 Ill. Adm. Code 240, Subpart E.
(Source: Amended at 26 Ill. Reg. 8113, effective May 17, 2002)