GoverningFuel-injection. Why does the diesel 2engine need a governor?Governor operation. Speed droop 4Governor functions 7Torque control 8

Governors – An overviewGovernor designation 10Maximum-speed governors 10Minimum-maximum-speed governors 10Variable-speed governors 12Combination governors 12Governors for engine-generator sets 13

Mechanical governingSpeed-sensing mechanisms 16Minimum-maximum-speed 16governors RQ, RQUMaximum-speed governors RQ, RQU 21Variable-speed governors RQV, 21RQUV, RQV..K, RSV, RSUVMinimum-maximum-speed 36governors RS, RSF

Add-on modules and shutoff devicesControl-lever stops 42Control-rack stops 43Manifold-pressure compensator (LDA) 47Altitude-pressure compensator (ADA) 49Manifold-pressure compensator, 50absolute metering (ALDA)Pneumatic idle-speed increase (PLA) 50Electronic idle-speed control (ELR) 51Anti-bucking device (ARD) 51Port-closing sensor (FBG) 52Rack-travel sensor (RWG) 53Temperature-dependent starting 54stop (TAS)Stabilizer 56Pneumatic shutoff device (PNAB) 57

Governor adjustment and testing 58

EDC-controlled PE in-line fuel-injection pumpsStandard PE in-line fuel-injection 60pumpsControl-sleeve in-line fuel-injection 66 pumps

Governors for dieselin-line fuel-injection pumps

Mobility in this day and age is notleast of all a question of commonsense and economy.In future, the technology withoutwhich these considerations regard-ing individual mobility are meaning-less will continue to be of decisiveimportance.In the automotive sector, economi-cal and quiet-running diesel enginesare making history.Bosch in-line and distributor injectionpumps have played, and continue toplay, a major role in these develop-ments. The introduction of electroniccontrols (Electronic Diesel Control/EDC), together with increased in-jection pressures and even moreprecise fuel metering, has made itpossible to further increase thediesel engine’s service life, as wellas reducing its exhaust-gas emis-sions, while at the same time evenfurther improving its fuel-economyfigures.In this “Technical Instruction” man-ual, from the Diesel Fuel Injectionseries, you have access to a wealth of information on a variety ofgovernors for different in-line fuel-injection pumps. This includes de-tails regarding their design andmethod of functioning, as well asinteresting information concerningmaximum-speed and intermediate-speed governing.The appropriate PE in-line fuel-injection pumps for the governorsare described in the Technical In-struction manual “Diesel in-line fuel-injection pumps PE”.

Mechanical governingThe Bosch mechanical (flyweight) gov-ernors are mounted on the fuel-injectionpump whose control rack is connectedwith the governor linkage. The governorcontrol lever is the connection to theaccelerator pedal.

Speed-sensing mechanismsMechanical governors use two differentdesigns of speed-sensing mechanism:– RQ, RQV: The governor springs areincorporated in the flyweights, wherebyeach flyweight acts directly on a springset which is designed specifically for agiven rated speed and for the corre-sponding speed droop.– RSV, RS, RSF: The centrifugal force isapplied through a system of levers to thegovernor spring which is located outsidethe two flyweights. The force from bothflyweights presses the sliding bolt againstthe tensioning lever which is being pulledin the opposite direction by the governorspring. With the RSV variable-speed gov-ernor, the driver tensions the governorspring via the control lever to select thedesired speed. With the RS and RSFminimum-maximum-speed governors,the governor spring is fixed at maximumspeed and cannot be influenced by thedriver.The governor springs for both formsof speed-sensing mechanism have beenselected so that spring force and centri-fugal force are mutually balanced at thedesired speed. When this is exceeded,the centrifugal force from the flyweights in-creases. A linkage system then adjuststhe control rack to provide a correspond-ing reduction in the delivery quantity.

RQ Minimum-maximum-speed governors DesignThe injection pump’s camshaft drives thegovernor hub through a vibration damp-er. The two flyweights with their bellcranks are held at one end in the gov-ernor hub. Each flyweight has its ownbuilt-in spring set. When the flyweights

move outwards due to centrifugal force,the bell cranks transform this (radial)movement into an axial movement at thesliding bolt. This axial movement is trans-ferred to the so-called slider. The slider,which can only shift along a straight linedue to its being held by the guide pin,provides the connection between theflyweight speed-sensing mechanism andthe control rack by means of the variable-fulcrum lever. There is a sliding blockguide in the variable-fulcum lever, andthe bottom end of the lever is held in thesliding block. The movable guide block isguided radially by the linkage lever whichitself is connected with the control leveron the same shaft. The control lever isshifted either by hand or through linkagefrom the accelerator pedal (Figs. 2 and3). When the position of the control leveris changed, the guide block is shifted andthe fulcrum lever tilts around the pivotpoint at the slider. When the governorcomes into effect, the guide block be-comes the pivot point for the fulcrumlever. The action of the sliding-blockguide and the guide block allows a vari-able lever ratio for the fulcrum lever.This arrangement ensures that enoughforce is always available to adjust thecontrol rack, even in the low-idle range, inwhich the centrifugal forces exerted bythe flyweights are still insufficient. Thespring sets (governor springs) in theflyweights (Fig. 1) generally comprise

Governorsfor in-line

fuel-injectionpumps

16

Flyweight for a RQ minimum-maximum-speed governor

1 Adjusting nut, 2 Outer spring seat, 3 Maximum-speed springs, 4 Idle-speed spring, 5 Flyweight,6 Inner spring seat.

1

2

3

4

5

6

Fig. 1U

MK

1185

Y

Mechanicalgoverning

17

RQ Minimum-maximum-speed governor

1 Control rack, 2 Link fork, 3 Play-compensating spring, 4 Adjusting nut, 5 Governor springs,6 Flyweight, 7 Bell crank, 8 Sliding bolt, 9 Slider, 10 Guide pin, 11 Control lever, 12 Fulcrum lever,13 Guide block, 14 Linkage lever.

RQ Minimum-maximum-speed governor

Stop (shutoff) position.1 Shutoff stop,2 Control lever,3 Full-load stop,4 Guide block, 5 Fulcrum lever,6 Link fork,7 Control rack,8 Pump plunger, 9 Control-rod stop (spring-loaded),

10 Slider,11 Guide pin, 12 Sliding bolt,13 Bell crank, 14 Governor hub, 15 Adjusting nut, 16 Governor spring,17 Flyweight,18 Camshaft.

Sto

p –

Full l

oad

–

1 2 3

4

5 6 7 8 9

10 11 12 13 14 15 16 17 18

1 2

3

4

5

6

11

12

13

14

7 8 9 10

Fig. 3Fig. 2

UM

K04

96Y

UM

K04

94E