Approval Details

Valid E.O.


This Executive Order approved the specified parts on on September 21, 1977.
As of Monday, October 21st, 2019 this Executive Order has not been overturned or superceeded.

Approved Parts

1977 and older model year gasoline powered motor vehicles using conventional carburetors and mechanical or electric fuel pumps with and without recirculation systems.

This Executive Order may be listed as:
  • C.A.R.B.E.O. D-75-1
  • Executive Order 75-1 / D75-1
  • ARB # D-75-1
  • Executive Order No: D-75-1
  • C.A.R.B. No. D-75-1
  • Resolution D-75-1
For Free CARB Executive Order Status verification, email an image of the device Executive Order label as well as the Year/Make/Model and Test Group # of the vehicle to [email protected]

Download: Executive Order D-75-1 PDF

D-75-1 Document:

                                                    (Page 1 of 2)

                          State of California
                          AIR RESOURCES BOARD

                        EXECUTIVE ORDER D—75—1
              Relating to Exemptions under Section 27156
                          of the Vehicle Code

                           CAGLE CORPORATION

Pursuant to the authority vested in the Air Resources Board by Section
27156 of the Vehicle Code; and

Pursuant to the authority vested in the undersigned by Section 39515 of
the Health and Safety Code and Executive Order G—30A;

IT IS ORDERED AND RESOLVED:   That the installation of the "Cagle Mark II
Automatic Fuel Control" device manufactured by Cagle Corporation,
400 Yellowstone Avenue, Pocatello, Idaho 83201 has been found to not
reduce the effectiveness of required motor vehicle pollution control
devices and, therefore, is exempt from the prohibitions of Section 27156
of the Vehicle Code for 1977 and older model! year gasoline powered motor
vehicies using conventional carburetors and mechanical or electric fuel
pumps with and without recirculation systems.

This Executive Order is valid provided that installation instructions
for this device will not recommend tuning the vehicle to specifications
different from those listed by the vehicle manufacturer.

Changes made to the design or operating conditions of the device, as
exempted by the Air Resources Board, that adversely affect the per—
formance of a vehicle‘s pollution contro1 system shall invalidate
this Executive Order.
Marketing of this device using an identification other than that shown
in this Executive Order or marketing of this device for an application
other than those listed in this Exeécutive Order shall be prohibited unless
prior approval is obtained from the Air Resources Board.

This Executive Order does not constitute any opinion as to the effect
that the use of this device may have on any warranty either expressed or
implied by the vehicle manufacturer.


No claim of any kind, such as "Approved by Air Resources Board" may be made
with respect to the action taken herein in any advertising orother oral
or written communication.

CAGLE CORPORATION                  2.             EXECUTIVE ORDER D—75—1
                                                        {Page 2 of 2)

Section 17500 of the Business and Professions Code make§ untrue or mis—
leading advertising unlawful, and Section 17534 makes violation punishable
as a misdemeanor.

Section 43644 of the Health and Safety Code provides as follows:

    "43644.   (a)} No person shall install, sell, offer for sale, or
    advertise, or, except in an application to the state board for
    certification of a device, represent, any device as a motor vehicle .
    pollution control dévice for use on any used motor vehicle unless
    that device has been certified by the state board. No person shall
    sell, offer for sale, advertise, or represent any motor vehicle
    pollution control device as a certified device which, in fact, is
    not a certified device. Any violation of this subdivision is a
    misdemeanor."                              >

Any apparent violation of the conditions of this Executive Order will be
submitted to the Attorney General of California for such action as he
deems advisable.           220.   —         —

Executed at Sacramento, California, th1s_ day of September, 1977.

                                   Deputy Executive Officer

                             State of California

                             AIR RESOURCES BOARD

                              September 15, 1977

                                Staff Report

                     Evaluation of the Cagle Corporation
             "Cagle Mark II Automatic Fuel Control" Device for
                Compliance with the Requirements of Section
                         27156 of the Vehicle Code


      On June 15, 1977 the Air Resources Board received an application

      from Cagle Corporation, Long Beach, California, requesting an

      exemption from the prohibitions of Vehicle Code Section 27156 for

      the "Cagle Mark II" fuel pressure regulator device.     (See Appendix

      A.).   The applicant requests that the exemption be granted for all

      1977 and older model year motor vehicles that are powered by gasoline

      engines with conventional carburetors and mechanical or electric

      fuel pumps with and without fuel recirculation systems.

II.   Device Description

      The "Cagle Mark I1I" is a fuel pressure regulator installed between

      the fuel pump and the carburetor.    It has three external fittings:

      (a) a fitting at the top for measuring intake manifold vacuum (b)
      an inlet fitting marked "PUMP" for connection to the fuel pump and

      {c) an outlet fitting marked "CARB" for connection to the carburetor.

      (See Figure 1 of Appendix A).   It is designed to reduce the fuel
      supply pressure under Tow demand conditions and also maintain the

      required fue! flow to the carburetor under all operating modes.     The

regulator is controlled by the intake manifold vacuum operating on

a spring balanced Buna—N diaphragm.    The materials of construction

are shown in Table I.   (Reference May 18, 1977 letter of DCL Corpora—

tion to Cagle Corporation in Appendix A.)

Table I Construction Material of the Parts used in the Device

               Part                            Material
          O—Ring Seal                       Viton—70 Shore

          Molded diaphragm                  Viton 70 Shore

          Stamped diaghragm                 Buna N—70 Shore

          Flat disc                         Cold roll steel, cadmium plated

          Cup shape retaining washer        Spring steel, cadmium plated

          Formed steel shape                Cold roll steel, cadmium plated

Reference is made to Figure 3 of Appendix A.   When the engine is

idling or cruising, the intake manifold vacuum draws the diaphragm

"H" upwards, thus compressing spring "F" and lifting plunger pin       >

"C" away from diaphragm "J". Diaphragm "J" is the fuel regulator

diaphragm controlling fuel pressure from the fuel pump to the

carburetor in the conventional manner of using opposing spring

tensions balanced to maintain a constant fuel supply pressure of 1

to 1 1/2 lbs. per square inch.

During periods of acceleration orheavy demand, the manifold vacuum

is substantially reduced which allows spring "F" to force plunger

pin "C" down on diaphragm "J" as in Figure 4 of Appendix A.   This

action then assists spring "O" to override the pressure regulator

At manifold vacuum     ranging from 0 to 20 inches Hg. and fuel pump

pressures of 3, 5, 7, 9 and 12 psig the graphs in Figure 2 to 7

of Appendix B show that the fuel pressure to the carburetor is

generally reduced.     In the operating range of 15 to 20 inches Hg.

manifold vacuum, the higher the fuel pump pressure the lower the

regulator outlet pressure.     This is not true for a lower manifold

vacuum condition.     Hence the device can maintain full discharge

pressure when the intake manifold vacuum is low {as in wide open

throttle, high speed operation) but can reduce delivery pressure

when the intake manifold vacuum is high (as in deceleration or

cruise conditions).

Figure 9 of Appendix B presents the DAECO data for a given fuel

flow rate (16 lbs. per hour) and fuel pump pressure (7.0 psig.)

showing the regulator outlet pressure as a function of steady—state

vacuum from 0 to 29 inches mercury.    This data shows a linear de—

crease in pressure to the carburetor between zero and 15 inches

manifold vacuum, and constant 1.1 psig regulator outliet pressure

at greater than 15 inches.

Figure 14 of the DAECO data (see Appendix B) shows the effect

of pump speed on regulator outlet pressure at a given constant

flow, fue! pump pressure and manifold vacuum.     Above 1500 RPM

the pump speed has no effect on the regulator outlet pressure.

Below that speed value, there seems to be a trend to increasing

     spring "N" which opens poppet valve "B" releasing more fuel flow to

     bring the fuel pressure higher as required.     The spring characteristics

     are shown in Table II.     (Reference May 23, 1977 letter of the

     Precision Coil Spring Company to Cagle Corporation in Appendix A.)

                Table II Spring rates and free lengths of the
                         Springs used in the device

                                     Free length                  Spring rate

Upper regulator spring                825 inch                    4.6 1b/inch

Lower regulator spring                450 inch                    2.1 1b/inch

Vacuum spring                         625 inch                    8.5 1b/inch

II1. Performance Evaluation

    A.    Applicant‘s Test Data

          Testing of the device for performance as described in the

          application was done by Daigh Automotive Engineering Co.

          (DAECO) (201 West "D" Street, Wilmington, California 90744).

          DAECO used a bench test flow procedure as shown in Figure 1 of

         Appendix B of the July 15, 1977 DAECO report titled "Flow Test

          of Cagle Mark I1 Automatic Fuel Pressure Control".       .The relation—

         ships between regulator outlet pressure, fuel pump pressure,

          intake manifold vacuum, and fuel flow from the DAECO tests are

         shown in Figures 2 to 7 of Appendix B.     Data fof five different

         fuel pumps with different pressures are shown.         (Reference

         July 15, 1977 DAECO report.)

regulator pressures as pump speed decreased.   DAECO attributed

this observation to the pronounced pressure and flow pulsations

which reduced gauge precision even though gauge snubbers were

installed.   Since the difference amounts to no more than about

0.3 psig from 1000 to 500 RPM, it is not considered a significant


Appendix B gives figures 11, 12, 13 and a discussion by DAECO

of the effects of fuel flow, regulator outlet pressure, intake

manifold vacuum and fuel pump pressure on the fuel level in

the carburetor float bow1.    The data shows that for the particular

specific test apparatus used by DAECO (Hitachi ISO Model

DAF 328—6—902 two barrel carburetor) the minimum fue]l level to

which the fuel Qi]l drop is 26/32 inch.    (Compared to a normal level

of 36/32 inch)}.   This assures that the fuel supply to the engine

is sufficient during all operating modes to prevent starvation.      The

decrease in fuel level in the carburetor float chamber would, however, have

the effect of leaning the air fuel ratio of the engine.

ARB Confirmatory Tests

The ARB flow and emission tests were performed on a 1971 V8

Ford 302, 2V engine installed on the engine dynamometer test

stand.    (See schematic diagram in Figure 1 of Appendix C and

reference Project No. 2V7706, Air Resources Board, 8—9—77).

Four operational modes were used to evaluate the pressure

                Table III ARB flow and emission data under 4
                         operational modes using the dyna—
                         mometer mounted 1971 V—8 Ford 302
                         2V engine

                            18 in Hg        15 in Hg      10 in Hg      10 in Hg
                            625 RPM         1000 RPM      1000 RPM      2000 RPM

1) Fuel pressure
   upstream from
   (Ibs per sq in.)              8.3           7.8              7.2        5.5

2) Fuel pressure
   from regulator
   to carburetor (psig.)         1.5           1.5              3.0        3.0

3) Fuel flow through
   carburetor with
   device (Ibs./hr.})            3.83          8.98            13.04      27.27

4) Fuel—Air Ratio
   (Baseline/device)        .099/.093        .074/ .070   076/ .074     .078/.077

5) Per Cent change
   in Fuel—Air Ratio
   from Baseline                —6.1          —5.4             —2.6       —1.3

6) HC emissions (gm/min.)
   Baseline/device          .425/ .336      .220/ .199    1.063/1.116   1.878/1.834
          % Change          —20.9             —9.5          —5.0          —2.3

7) CO emissions (gn/m#
   Baseline/device          8.56/76.14      1.98/0.98     4.99/2.26     26.65/20.41
          % Change          —28.3            —50.5         —54.7         —23.4

8) NOx emissions (gm/min.)
   Baseline/device          .047 .04        0.50/0 .36    3.67/3.98     8.76/9.13
          % Change          0           &    =28.0           8.4           4.2

reductions by the "Cagle Mark II" device:     18 inches Hg at 625

RPM, 15 inches Hg at 1000 RPM, 10 inches Hg at 1000 RPM, and

10 inches Hg at 2000 RPM.     The results are shown in Table III.

This data shows that when the device is installed, the pressure

to the carburetor is decreased and the fuel—air ratio is decreased

by an average 4% under all four test modes.     This resulted in leaner


Table III shows the precent change in CO emissions from the baselTine

which verifies that the device causes the engine to run leaner re—

sulting in an average 39% decrease in CO emissions.     The HC emissions
decreased an average of 9.4% which is beneficial to the emission

control system.   The NOx emissions increased an average of 6% but it

is not considered serious because it is within the variability of

experimental error.   NOx emissions with this device may either increase

or decrease depending on which side of stoichiometric the carburetor

is predominantly operated.    The effect on emissions varied with the

test conditions and the overall effect is not considered deleterious

to the total emissions control when used on engines operating at an

equivalence ratio greater than one.     [Equivalence ratio equals Fuel—

Air Ratio (actual) divided by Fuel—Air Ratio (stoichiometric)].

The Teaning effect of this device can be explained as follows:

(Reference ARB Report May 25, 1976:     Evaluation of Alondra, Inc.

"Filt—O—Reg" device for compliance with the requirements of Section

27156 of the Vehicle Code).

The carburetor float valve operates as a variable orifice where

the flow rate (m) is described by
m = CdA    2gpAp = KZ d 2gpP2

Cd = discharge coefficient           p = fuel density

A   = orifice area                  Ap = pressure differential (Pz—Patm)

g   = gravitational constant P2 = carburetor inlet pressure

Kz = CdA as a function of the float level, z, where z is

the Tiquid height above a reference.

Reducing the carburetor inlet pressure (PZ) requires a

higher KZ to‘maintain any flow rate {m) into the bow1.     This

requires a slightly lower float Tevel and fuel level in the

bow1 (Az).

The Tower fuel level decreases the head required by the main

and idle circuits and reduces the fuel flow for any throttle

{(air flow) setting:    this fuel reduction is more significant

at low engine speeds where Ap across the venturi is small

(Ap=Az).     The result is a Teaner fuel/air mixture.

Increasing the carburetor inlet pressure reverses the above

process and raises the float and fuel Tevel.     This results

in enrichment.

The Teaning of an engine that already runs Tean will lead to
misfires because the fuel flow out of the main and idle

circuits is reduced.

      The percent decrease in fuel—air ratio from baseline to device range

      from 6% at idle to 1% at 10 in. Hg and 2000 RPM.    The "Filt—O—Reg"

      device exempted by the ARB had a per cent decrease of 7% at idle and

      1% at 10 in. Hg and 2000 RPM.   The pressure reductions of the Cagle

      device are 7 psig at idle and 2 psig at 10 in. Hg and 2000 RPM.      The

      pressure reductions of the "Filt—O—Reg" are 7 psig at idle and 3 psig

      at 10 in. Hg and 2000 RPM.

      The air—fuel ratio (reciprocal of fuel—air ratio) increased to an

      average 0.5 from the baseline value which meets the Air Resouces Board

      allowable increase of 1 AFR.    Since the device displayed similar

      characteristics of a device previously exempted by the ARB and since

      the air—fuel ratio increase was less than one the staff cannot find

      any reason to deny Cagle Corporation an exemption for their "Cagle

      Mark I1 Automatic Fuel Pressure Control" device.

Iv.   Evaluation of Advertising Claims

      The applicant has implied fuel economy as the advertising claim when

      the "Cagle Mark II" device is installed in a motor vehicle.   According

      to the applicant‘s July 5, 1977 and June 15, 1977 letters to ARB

      "marketing will be carried on by demonstration rather than claims."

      (See Appendix A).   Although the applicant has not submitted any

      supporting data to substantiate fuel economy claims the ARB staff

      feels that the use of the device may give increased mileage on some

      vehicles due to the leaning effect on engines which are running rich.

Conclusion and Recommendations

Based on the test data, the staff believes that the use of the

"Cagie Mark II" device will not lead to increased emissions and
recommends that Cagle Corporation be granted an exemption from the

prohibitions of Vehicle Code Section 27156 for 1977 and older mode]

year gasoline powered motor vehicles using conventional carburetors

and mechanical or electric fuel pumps with and without fuel recircula—

tion systems.

Appendix A

1)   Letter from Mr. Kilbourne to Mr. Hass       6—15—77

2)   Letter from Mr. Drachand to Mr. Kilbourne   *6—27—77

3)   Letter from Mr. Kilbourne to Mr. Drachand   7—5—77

Document Created: 2005-09-01 12:45:04
Document Modified: 2005-09-01 12:45:04

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