76-12 RBM
Mini Turbo-Charger Air Bleed:
Evaluation on a Light Duty Gasoline Powered Vehicle
January 1976
Technology Assessment and Evaluation Branch
Emission Control Technology Division
Office of Mobile Source Air Pollution Control
Environmental Protection Agency
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Background
The Environmental Protection Agency (EPA) first became interested
in the Mini Turbo-Charger air bleed device (also marketed under the name
of "Air-Jet") in 1972. At that time the manufacturer of the device,
Albano Enterprises, requested that the EPA conduct an evaluation of the
device to determine its effects on pollutant emissions when installed in
an automobile. The EPA conducted a test program in the summer of 1972,
testing a vehicle for emissions on the 1972 Federal Test Procedure ('72
FTP), both with and without the device installed." It was found to be
marginally effective for CO reduction but had little effect on HC or
NOx.
Recently the Federal Trade Commission contacted EPA concerning
claims made for the device which is now being marketed as a fuel economy
improver. They provided data which to some extent supported the adver-
tised claims but also some data which showed little effect. Since the
original EPA test did not specifically look at fuel economy and because
the advertised claims were different from those made in 1972, a retest
was made on two of the devices using the 1975 Federal Test Procedure and
measuring both urban and highway fuel economy. The test program was
begun in late December 1975 and completed in January 1976.
The Environmental Protection Agency receives information about many
devices for which emission reduction or fuel economy improvement claims
are made. In some cases, both claims are made for a single device. In
most cases, these devices are being recommended or promoted for retrofit
to existing vehicles although some represent advanced systems for
meeting future standards.
The EPA is interested in evaluating the validity of the claims for
all such devices, because of the obvious benefits to the Nation of
identifying devices that live up to their claims. For that reason the
EPA invites proponents of such devices to provide to the EPA complete
technical data on the device's principle of operation, together with
test data on the device made by independent laboratories. In those
cases in which review by EPA technical staff suggests that the data
submitted holds promise of confirming the claims made for the device,
confirmatory tests of the device are scheduled at the EPA Emissions
Laboratory at Ann Arbor, Michigan. The results of all such confirmatory
test projects are set forth in a series of Technology Assessment and
Evaluation Reports, of which this report is one.
The conclusions drawn from the EPA confirmatory tests are necessarily
of limited applicability. A complete evaluation of the effectiveness of
an emission control system in achieving its claimed performance improvements
on the many different types of vehicles that are in actual use requires
a much larger sample of test vehicles than is economically feasible in
the confirmatory test projects conducted by EPA. I/ For promising
devices it is necessary that more extensive test programs be carried out.
*
Report #73-2, "Evaluation of the Air-Jet Device-Air Bleed,"
August 1972, EPA, TAEB.
I/ See Federal Register 38 FR 11334, 3/27/74, for a description of the
test protocols proposed for definitive evaluations of the effective-
ness of retrofit devices.
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The conclusions from the EPA confirmatory tests can be considered
to be quantitatively valid only for the specific type of vehicles used in
the EPA confirmatory test program. Although it is reasonable to extrapolate
the results from the EPA confirmatory test to other types of vehicles in
a directional or qualitative manner, i.e., to suggest that similar results
are likely to be achieved on other types of vehicles, tests of the
device on such other vehicles would be required to reliably quantify
results on other types of vehicles.
In summary, a device that lives up to its claims in the EPA confirmatory
test must be further tested according to protocols described in footnote _!/
to quantify its beneficial effects on a broad range of vehicles. A device
which when tested by EPA does not meet the claimed results would not
appear to be a worthwhile candidate for such further testing from the standpoint
of the likelihood of ultimately validating the claims made. However, a
definitive quantitative evaluation of its effectiveness on a broad range
of vehicle types would equally require further tests in accordance with
footnote "\J.
Device Description
The Mini Turbo-Charger is an engine vacuum actuated valve which allows
air to bleed into the intake manifold via the PCV system. The valve is
said to be designed so that under conditions of high manifold vacuum
the actuator valve is closed and no additional air is allowed to the
manifold. The valve opens when the vacuum is reduced, to allow additional
air to the engine. According to literature provided by the manufacturer
of the device, the valve is closed at conditions of idle and up to 35-40 mph;
over 40 mph the valve is open. It should be noted, however, that manifold
vacuum varies with accelerations and decelerations as well as different
cruising speeds. An acceleration from idle could provide a very low
vacuum, lower than highway cruising speeds, and therefore the valve
would be open during this mode.
The device is installed in the PCV line.between the PCV valve and
the carburetor and installation takes only a few minutes.
Test Procedure
Exhaust emissions tests were conducted according to the 1975 Federal
Test Procedure described in the Federal Register of November 15, 1972.
Additional tests included the EPA Highway cycle, steady state conditions
of idle, 15, 30, 40, 50 and 60 mph, and vehicle acceleration tests on
the dynamometer of 10-60, 20-60 and 30-60 mph. Zero to 60 mph accelerations
could not be run because the acceleration rate was too high for the
dynamometer's capability. These tests were conducted both with and
without the device installed.
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MINI TURBO-CHARGER
Air Bleed Device, ~k'.5X Actual Size
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The vehicle used in the test program was a 1971 Ford Galaxie with a
351 CID (5753 cc) engine and automatic transmission (a complete vehicle
description is given on the following page). All tests were conducted
using an inertia weight setting of 4500 pounds (2041 kg) with a road
load setting of 12.7 horsepower (9.47 kW) at 50 miles per hour (80.5
km/hr). The test vehicle was first tuned to the manufacturer's specifi-
cations and then no adjustments were made after the program began;
installation of the device requires no re-tuning of the engine.
Test Results
Exhaust emissions and fuel economy data are summarized in Tables 1,
2, and 3 below. Acceleration results are summarized in Table 4.
On the 1975 FTP and on the EPA Highway Cycle, with the device
installed, hydrocarbon mass emissions (HC) increased, carbon monoxide
(CO) and oxides of nitrogen (NOx) decreased, and fuel economy decreased
slightly.
Mixed results were obtained on the steady state tests. HC increased
at idle, 15, 30, and 40 mph but decreased at 50 and 60 mph; CO decreased
at idle and 60 mph, but increased in all the other speeds; NOx was
reduced at all conditions; idle fuel consumption decreased with the
device installed, but fuel economy decreased at all other steady state
conditions.
No significant differences were noted on the dynamometer accel-
eration tests with the device installed. Driveability, however, was
worsened with the device. The engine idled roughly and the test driver
noticed that it was more difficult to make smooth speed changes, such as
when driving the car on a "75 FTP, with the device installed.
Although the device is not supposed to allow extra air to enter the
engine (valve closed) at conditions of high vacuum such as idle, the
valve was open at idle, and appears to have been open at all conditions;
the changes noted at all steady state conditions seem to confirm this.
After the test program was completed, the device was checked on
three other vehicles and was observed to be sucking in air at idle on
all the vehicles. A vacuum gage check showed that even at 20" Hg vacuum
the valve was open (this was checked simply by holding one's hand at the
top of the device and feeling the suction). A duplicate device which
was supplied by the FTC gave the same results, and to make sure there
was no malfunction, such as a stuck valve, it was taken apart and inspected,
It was found to be in satisfactory condition, the valve closing with
pressure applied to the top of the piston. Idle CO was checked with the
device installed on the test vehicle as a further check. The device
caused a reduction from the baseline condition of 0.5% to about 0.2% CO.
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TEST VEHICLE DESCRIPTION
Chassis model year/make - 1971 Ford Galaxle
Engine
type 4 stroke Otto cycle, OHV, V-8
bore x stroke 4.00 x 3.50 in/102 x 89 mm
displacement 351 cu in./5753 cc
compression ratio 9.0/1
maximum power @ rpm 240 hp/179 kW @ 4600 rpm
fuel metering 2 barrel carburetor
fuel requirement 91 RON
Drive Train
transmission type automatic (3 forward gears)
final drive ratio 2.75:1
Chassis
type body/frame, front engine, rear wheel drive
tire size H 78 x 15
curb weight 4130 lbs/1873 kg
inertia weight 4500 lbs/2041 kg
passenger capacity 6
Emission Control System
basic type engine modifications, PCV
Engine Specifications (at idle
in Drive)
speed 600 rpm
dwell angle 27
CO concentration 0.5%
spark timing 6° BTDC
manifold vacuum 15.5" Hg (measured value)
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Table 1
'75 FTP Composite Mass Emissions
grams per mile
(grams per kilometre)
HC
CO
NOx
Baseline - mean of 2 tests 2.74 20.4 3.60
Device - mean of 2 tests
% Change
3.21 8.24 2.80
+17% -60% -22%
Fuel Economy
(Fuel Consumption)
13.88 miles/gal
(16.95 litres/100 km)
13.38 miles/gal
(17.58 litres/100 km)
-4% in miles/gai
(+4% in litres/100 km)
Table 2
EPA Highway Cycle Mass Emissions
grams per mile
(grams per kilometre)
HC
CO
NOx
Baseline - mean of 2 tests 1.00 3.55 4.16
Device - mean of 2 tests
% Change
1.24 3.04 3.16
+24% -14% -24%
Fuel Economy
(Fuel Consumption)
20.8 miles/gal
,(11.31 litres/100 km)
20.1 miles/gal
(11.70 litres/100 km)
-3% in miles/gal
+3% in litres/100 km)
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Ta)le 3
Steady State Mass Emissions
grams per mile
Speed
*
Idle
15
30
40
50
60
(mph)
Baseline
Device
% Change
Baseline
Device
% Change
Baseline
Device
% Change
Baseline
Device
% Change
Baseline
Device
% Change
Baseline
Device
HC
.68
1.33
+96%
2.19
10.03
+358%
.94
1.80
+91%
.76
.90
+18%
.62
.58
-6%
.66
.45
CO
3.34
0.66
-80%
2.97
4.94
+66%
1.97
2.99
+52%
2.17
2.67
+23%
2.20
2.64
+20%
3.06
2.55
NOx
.23
.05
-78%
.58
.21
-64%
.77
.28
-64%
1.42
.60
-58%
3.09
1.76
-43%
5.35
3.55
Fuel Consumption
/Economy
.737 gal/hr
.666 gal/hr
-10% (consumption)
19.6 miles/gal
16.8 miles/gal
-14%
26.5 miles/gal
22.5 miles/gal
-15%
24.6 miles/gal
23.1 miles/gal
-6%
23.1 miles/gal
22.3 miles/gal
-3%
20.9 miles/gal
20.8 miles/gal
% Change -32%
Emissions in grams per minute
-17% -34%
0%
Table 4
Dynamometer Acceleration Results
Time, seconds
. 10-60 mph 20-60 mph 30-60 mph
Baseline - mean of 3 tests 8.9 7.7 6.0
Device - mean of 3 tests 8.9 7.7 6.1
% Change 0% 0% +2%
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Conclusions
The Mini Turbo-Charger air bleed device caused a small decrease in
fuel economy when installed on the EPA test vehicle, on both the 1975
FTP and the EPA Highway Cycle. The increase in hydrocarbon emissions
was probably due to a lean misfire condition, the decrease in CO to the
enleanment effect, and the decrease in NOx to a combination of the
misfiring and enleanment. Acceleration performance was unchanged and
driveability worsened with the device.
Because most vehicles since 1971 are already operating at a relatively
lean air-fuel ratio, a further enleanment of the mixture can have adverse
effects on the fuel economy, pollutant emissions, and performance of the
vehicle.
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Appendix
Table 1-A
'75 FTP Composite Results
Mass Emissions, gpm
Fuel Economy, mpg
1. Baseline
Test Date Test No. HC CO C00
1-6-76 77-3 2.81 22.2 592
1-7-76 77-4 2.66 18.6 605
MEAN 2.74 20.4 598
2. Device
1-8-76 77-49 3.18 8.50 640
1-9-76 77-51 3.24 7.99 640
MEAN 3.21 8.24 640
NOx Fuel Economy
3.72 13.95
3.49 13.81
3.60 13.88
2,75 13.37
2.85 13.39
2.80 13.38
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Table 2-A
'75 FTP Individual Bag Results
Mass emissions, grams per mile
Fuel economy, miles per gallon
Test Number
Baseline
77-3
77-4
HC
Bag 1 Cold Transient
Fuel
CO C09 NOx Economy
3.80 50.1 628
3.36 46.6 638
4.50 12.3
4.52 12.3
HC
Bag 2 Hot Stabilized
Fuel
CO CO,, NOx Economy
2.76 17.9 600
2.62 12.7 615
2.86 13.9
2.61 13.8
Bag 3 Hot Transient
HC
CO
CO,
2.16 9.50 549
2.21 8.86 563
NOx
4.77
4.39
Fuel
Economy
15.5
15.2
Device
77-49
77-51
3.12 21.3 684 4.12 12.2
3.05 18.0 675 4.16 12.4
3.06 4.37 660
3.23 4.35 663
1.82 13.1
1.96 13.1
3.44 6.70 569
3.40 7.41 571
3.51 15.0
3.56 15.0
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11
Table 3-A
EPA Highway Cycle
Mass Emissions, gpm
Fuel Economy, mpg
1. Baseline
Test Date Test No.
1-6-76 77-3
1-7-76 77-4
MEAN
1-9-76 77-50
1-9-76 77-52
MEAN
HC
.99
1.02
1.00
2.
1.18
1.31
1.24
CO
3.63
3.47
3.55
Device
2.98
3.09
3.04
C0n
415
420
418
434
432
433
NOx
4.24
4.08
4.16
3.08
3.23
3.16
Fuel Economy
20.9
20.7
20.8
20.1
20.1
20.1
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12
Run
1
2
3
MEAN
Appendix
Table 4-A
Dynamometer Acceleration Results
Time, seconds
1. Baseline
10-60 mph 20-60 mph
8.9 7.7
8.9 7.6
9.0 7.7
8.9 7.7
33-60 mph
6.0
6.0
6.0
6.0
1
2
3
MEAN
2. Device
8.9
8.9
8.8
7.7
7.7
7.6
6.1
6.1
6.1
8.9
7.7
6.1
* US. GOVERNMENT PRINTING Off ICE: 1979- 651-112/0122
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