US 3374667 A
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Description (OCR text may contain errors)
March 26, 1968 H. o. MAYER TESTER SYSTEM FOR DIESEL FUEL PUMPS 2 Sheets-Sheet l Filed OCt. 22, 1965 March 26, 1968 H. O. MAYER 3,374,667
TESTER SYSTEM FOR DIESEL FUEL PUMPS Filed Oct. 22, 1965 2 Sheets-Sheet 2 [33 INVENTOR, f f
HELMUT emma-Q Fig. 4
United States Patent O 3,374,667 TESTER SYSTEM FOR DIESEL FUEL PUMPS Helmut O. Mayer, Middletown Township, Monmouth County, NJ., assguor of thirty percent to Richard A. Marsen, Middletown, NJ.
Continuation-impart of application Ser. No. 223,119, Sept. 12, 1962. This application Oct. 22, 1965, Ser. No. 522,335
8 Claims. (Cl. 73--119) This invention relates generally to portable testers for fuel pumps of diesel engines, and more particularly to the novel testing, measuring or calibration of their pumping action in-position and during engine operation. This is a continuation-in-part of my copending patent application Ser. No. 223,119 led on Sept. 12, 1962, for Portable Tester for Diesel Fuel Pumps, now U.S. Patent No. 3,245,254.
Fuel pumps are used to controllably deliver fuel oil 'under high pressure to the spray nozzles through which the fuel is injected into the cylinders of the diesel engine. The quantity of fuel oil delivered to each cylinder is accurately measured by corresponding section of the pump, and at optimum is identical for each cylinder, in timed sequential relation, per pump shaft revolution. Further, such measured quantity is controlled in amount per pump revolution, or stroke, through a control rack extending from the pump. The control rack is coupled to a speed governor and to leverage, as the accelerator pedal, for manual control. The invention tester is also useful for fuel injection pumps with sections arranged in a circle, termed distributor pumps, for diesel engines.
The arrangement and construction details of fuel pumps, per se, are varied and well known in the art, forming no part of the present invention. A widely used in-line pump type has a self-contained cam and tappet combination to operate an individual plunger for each spray nozzle and cylinder of the engine. These plungers have a constant displacement, in timed separation, through the cam. A control sleeve is concentric with and coupled to each plunger to control its angular orientation with respect to a spill port. A common control rack, linearly displaceable, establishes the settings of all the plungers, and in turn the precise quantity of fuel oil delivered by each plunger per stroke. Manual or governor control of the pump rack setting thereby determines the speed and/ or power output of the engine in a manner understood by those skilled in the art.
For etlicient and smooth performance of the diesel engine, it is important that each of the pump sections delivers the same quantity of fuel oil per stroke to its spray nozzle, and that such delivered quantity corresponds to the control rack position or setting. This fuel is delivered at very high pressure over short time intervals or spurts. The spray injections by the nozzles occur at definite points in the engine cycle, and within a limited number of degrees of engine crankshaft rotation. In four-stroke-cycle engines, as in trucks, the pump camshaft is usually geared to rotate at half the engine speed.
When engine performance is impared it is important to know the condition of the fuel injection pump. Heretofore it has been necessary to dismantle the whole pump assembly from the engine, as its pumping sectional performance had to be determined on a test stand. Over fifty percent of the pumps so removed from diesel engines are found to be in good condition when tested.
The hours of unnecessary down time of the engine, and wasted skilled labor in demounting and remounting the pump, are saved by the use of the present invention. Further, the on-engine tester hereof checks the calibration of fuel delivery of each pump section over its op- ICC erating range. When any plunger is thereby found to be 01T it is readily reset through its control sleeve to the rated position. In this way fuel pumps with merely upset plunger control settings are recalibrated in-position by the present invention. This feature is very useful in checking-out fuel pumps when first installed on their engine; and in final check-out of trucks, tractors, buses, marine and stationary engines, and the like, upon cornpletion on the production line.
In accordance with the present invention the engine itself is utilized to operate the fuel pump while each test and/or calibration is made. Only one spray nozzle for the pump section being tested is disconnected at any one time from its associated injection spray nozzle, and the engine is operated on its remaining cylinders. Thus a six-cylinder engine is powered through five of its spray nozzles during each test run herein. The engine is not loaded beyond its contained idle-load of neutral, even for its beyond-idle-speed settings, as will be hereinafter set forth. Thus, in a vehicle, the wheels are braked and the shift placed in neutral. I have found that the diesel engines run smoothly, do not race or lug, and are fully safe in their operation with the one less cylinder during the testing.
Further, with my invention system, the pump control rack may be moved to its maximum fuel delivery per stroke setting, yet the engine power and speed, in neutral shift, is safely controlled in such tests hereof. Toward this end, means are provided to controllably divert a portion of the fuel oil otherwise delivered at each stroke to each of the active cylinders from the pump sections. In this manner all the pump sections deliver fuel spurts in accordance with the rack settings. The output of the selected pump section is measured, by calibrating its fuel output over a given number of strokes, as 500. However, the activated engine cylinders receive only a controlled percentage of the pump output, in using the invention hereof.
The invention tester is portable, self-contained, yand light in weight. It is readily installed for the testing operations, with the fuel pump and the engine al1 in-position; and the individual pump sections are `rapidly tested, measured or calibrated over idle, intermediate and full rack positions. The engine itself smoothly operates the pump during its test runs herewith. The fuel pump, tested inposition, operates with its regular spray nozzles and fuel lines and engine environment. Its operation and testing, measuring `or calibration thus on-engine is very practical and economical for use in the manufacturing plant and in the eld. The invention hereof is used to test in-lne as well as rotary or `distributer types of diesel fuel pumps.
The above land further features, objects and advantages of the present invention system will become more apparent from the following description of exemplary embodiments and utilization thereof, illustrated in the accompanying drawings, in which:
FIG. l illustrates a tester diagrammatically, as shown and claimed in my aforesaid patent application, for inposition testing, measuring or Calibrating of a fuel pump.
FIG. 2 is a face view of the Calibrating -vessel of the tester.
FIG. 3 is an illustration, in part, of the novel tester system of this invention.
FIG. 4 is an enlarged vertical cross-sectional view through the control unit of FIG. 3, taken along the line 4 4 thereof.
The tester system 35 of FIG. l utilizes `a self-contained fuel measuring unit or calibrator 20. The calibrator 20 is in a portable cabinet 21 and contains Calibrating elements that measures the fuel discharge from a selected pump section. The cabinet 21 contains a bleed-olir control unit 45 with its lever 46 extending' for manual setting. However, unit 45 need not be mounted in calibrator 20. Further, the calibrator per se may take several forms, for Yuse in the tester systems of this invention.
The specific function of the calibrator 20 is to accurately measure the fuel discharge over a given number of strokes or interval of operation of any selected section of the pump being tested. Calibrator 20 per se is indicated schematically, as its details of construction are optional herein. The control unit 45 of the present invention is shown incorporated in the calibrator cabinet 21. lt may be separate therefrom.
Calibrator 20 is coupled directly to the fuel pump section to be calibrated. The fuel pump 36 has six sections, with output or discharge couplings 37-1, 37-2 37-6. Pump section 371 is under calibration in FIG. 1. It is connected to the input coupling 22 of calibrator 20 by high pressure line 38. The fuel injection pump 36 is shown in block schematic form, its construction being well known in the art. Pump 36 is driven through coupling 39 to t the engine 51 which it feeds. Coupling 39 rotates the internal six-section cam that operates the plungers of the six pump sections in succession, once per cam shaft rota- Vtion or stroke Each plunger forces its measured amount of fuel oil through 'a discharge or delivery valve, preset at a high pressure. The delivery valve of each section extends to the tubing union nut and washer 37 forming an independent output for the spray nozzles. The longitudinal position or setting of the control rack 40 precisely determines the quantity of fuel oil ejected by each plunger through its delivery valve and output coupling 37. Rack 40 may be manually set by linkage (not shown), and is also set by a mechanical speed governor 41 in a well known manner. The fuel pump 36 is illustrated separate from its engine 51 or equipment mounting, for clarity, it being understood that its testing and calibration herein does not entail dismantling.
During the calibration of any one of the pump sections, the remaining ones, as 37-2, 37-3 37-6 of FIG. 1, are connected to feed their associated spray nozzles 50-2, 50-3 50-6, as illustrated. The regular high pressure lines 52 of the engine remain in place, and in connection with the spray nozzles 50. A three-way coupling unit 55 is inserted between each pump output coupling 37-2, 37-3 37-6 and the line 52 for its spray nozzle 50. A short high pressure line or link 53 couples the input of each unit 55 to its pump delivery output coupling 37. A highV pressure line 54, in turn, connects each coupling unit 55 to the bleed-olf control unit 45.
The engine 51 is started up in the usual manner, with tester system 35 connected-up to it as in FIG. l, and as generally set forth hereinabove. The control lever 46 is set to zero or low bleed-off position. Fuel lfrom the (five) pump sections 37-2, 37-3 37-6 is thereupon injected 1in turn to their associated spray nozzles 50 through coupling -units 55 and lines 52. The engine 51 is kept in neutral shift. The control rack 40 is placed in low power or idle position for low bleed-olf settings of lever 46. Fuel pump section 37-1 feeds directly into calibrator 20, while the engine 51 operates and turns the pump cam shaft at 39.
Details of the bleed-off control unit 45 and its -func- -tion herein are described in the aforesaid patent application. Control unit 45 is basically a variable by-pass valve common to all the bleed-off lines 54. In essence, controlled proportions of the fuel directed to the operating spray nozzles 50 are diverted through by-pass tubes 54 and unit 45. Such diverted fuel isV expelled from unit 45 through spill tube 47, at low pressure. Suicient fuel however is injected at each stroke into each operating cylinder to effect firing and engine operation.
In the FIG. 1 set-up, all the fuel exiting each stroke from pump output 37-1 enters into calibrator input 22, with the line 52 to nozzle 50-1 left unconnected to the pump 36. VIn turn, all of the pump sections 37 .are indi-` vidually calibrated, in the same manner as described for 37-1. The last tested section, e.g. 37-1, has its test line 38 removed; the coupling unit 55 then on the section next to be tested (eg. 37-2) is uncoupled from the delivery coupling 37-2 and nozzle line 52, the test line 38 is then coupled directly to the new section 37-2.
The bleed-off lines 54 are not phased,V so that it is unnecessary to reorient their connections to the coupling units 55, when a new pump section is connected for caibration. However, the unit 55 removed from the next section 37-2 has its link 53 coupled to the last tested section 37-'1, and the corresponding nozzle line 52 connected aswell. This leaves the lineV 52 for spray nozzle 50-2 open, the five remaining nozzles 50 coupled to the pump 36, and pumpsection 37-2 directly coupled tothe calibrator 20 through test line 38,. Similar reconnections are employed to individually test each of the pump section 37-1, 37-2 '37-6. To facilitate connections of the system 35 for calibration of a pump 36, snap-type couplings may be used for bleed-off lines 54 with uni'.s 55.
In a pump section test changeover, the spray nozzle line 52 is then uncoupled from unit 55. The linkwline 53 is finally uncoupled at delivery end 37-6. Reconnection of three-way coupling unit 55 for the following test is readily accomplished with link line 53 coupled to the previously calibrated section end 37; the corresponding nozzle line 52 coupled to the top of unit 55; and the bleed-olf coupling end snapped back onto the nipple end at the unit 55.
Coupling units 55 serve to connect the fuel oil spurts pressed (at high pressure, e.g. 2300 p;s.i.) through the delivery valve outputs i37 of the pump 36 to their corresponding spray nozzles 50, as well as to the bleed-olf unit 45. A T configuration Ibored through each unit 55, with simple communicating bores to their associated three lines 52, 53, 54, effects this end as shown in said application. Unit 55 is 'built to withstand the high pressures, and its bores are of the same I.D. as that of the nozzle' lines 52. Link lines 53 are made short, as of the order of one inch, and have a turn. The stiff nozzle lines 52 are thus readily connected, close by their normal terminations, even if little clearing exists in any pump installation.
In the tester system 35, then, the pump sections 37 are calibrated individually, one at a time. The (ve) remaining pump sections in any test run, are arranged to feed their spray nozzles 50 and cylinders, to operate the engine 51 during each test run. Each pump section 37 is calibrated at least at low, intermediate and high or full rack 40 settings. System 35 arranges to` divert controlled proportions of the fuel meant for the operating nozzles 50, to prevent racing of or damage to the engine.
The control unit 45 and its associated `bleed-off lines 54 draw off sufficient fuel during each stroke to hold the engine 51 at desirable speed (and power) levels, while in neutral shift.V Thus the rack 40 may be safely extended to its full setting, with maximum fuel amounts delivered through all the pump sections 37, each pump stroke. The spray nozzles 50 do not therefore know when the rack 40 is fully extended, because they then receive considerably less of each fuel spurt. This is caused by the bleed-olf of a preset percentage of each fuel spurt from the operating sections, into unit 45.
The rotating engine 51 therefor also rotates the pump 36 camshaft. All the pump sections thereupon operate to deliver measured amounts of fuel oil through their delivery outlets 37, at each stroke, which measures are determined by the common rack 40 setting, as aforesaid. It is such operation of the engine 51 with safety, despite even full rack 40 settings of its pump, that renders in-position calibration of the pump practical. The pump section 37-1 Y being calibrated, (see FIG. 1), delivers measured fuel at each stroke, to the test line 38. Its fuel measure is dependent directly on its plunger control sleeve angular orientation, determined lby the rack l40 setting, as described hereinabove. The calibrator 20 is used to thereupon accurately calibrate this output against rack 40 settings, in a manner to be described.
The fuel delivered from the operating pump sections 37-2, 37-3 37-6, into coupling units 55, is normal ly, the same as that delivered by the on-test section 37-1, for any given rack 40 setting. Nevertheless, as set forth, the `by-passing or *bleed-off of a preset proportion of such fuel output at each stroke from each unit 55, prevents the engine power and speed from running away or damage, since no load, or wheels, or external braking is applied during calibration with the invention hereof.
As the rack 40 setting is increased, more fuel is delivered per stroke by all the pump sections 37. The engine `51 thereupon picks-up speed, further increasing the amount of fuel it would receive per second for given settings of rack 40 and lever 46. The bleed-off control lever 46 is manually operated when the rack `40 setting is changed. In this way, one may increase the rack 40 setting during a test-run, and moderate the increase in R.P.M. of the engine 51 and pump 36. I have found such dual 40, 46 settings control to be simple, effective, and safe under all testing conditions, The tachometer 23 in calibrator 20, coupled to the engine through cable 24', is observed during the resettings of control lever 46 and rack 4t).
The exemplary calibrator accurately measures the output volume of fuel oil discharged through the delivery valve of the pump section being tested (37-1 in PIG. 1), at any setting of the control rack 40. The fuel test line 3S coupled to the output 37-1 is preferably of the same pressure rating and internal diameter as the engines nozzle lines 54. Line 38 is securely coupled to calibrator input coupling 22. Coupling 22 connects directly with a master spray nozzle 25 firmly bolted onto a frame 24 that contains a chamber filled up with fuel oil previously sprayed in.
Nozzle 25 is replaceably mounted, a different one may be inserted for each engine type. The master nozzle used is preferably, but not necessarily of the identical size and type as those 50 used in the engine 51 under test; being optionally factory calibrated for performance to specification. A typical American Bosch injection spray nozzle, as used in six-cylinder truck diesel engines rated at 175 horsepower contains an adjustable spring set for its opening pressure for fuel injected therein by the pump operative at the order of 2300 p.s.i. Each delivery valve at outputs 37 of the pump 36 is set to open as at 500 p.s.i. in operation.
The pump section 37-1 under calibration is thus op tionally operated under conditions that closely simulate those when the engine 51 and pump 36 are in normal use. Its fuel output through nozzle 25, per stroke in-test, thus will closely be that as though it were in engine use, at all rack 40 settings. The total fuel volume discharged through master nozzle 25 over a precise number of strokes, provides the calibrated delivery of fuel by the section in-test 37-1, for any rack 40 setting. A practical stroke total of 500 yields accurately measurable uid volumes for most test settings.
Towards this end a solenoid valve 26 connects to an output port of the chamber 24 (not shown). When `solenoid valve 26 is energized it instantly establishes fuel flow from the chamber 24 out through calibration spout 27. Such energization and calibration-flow is initiated at the start of each test run, and is maintained until the pump cam shaft at 39 has rotated for exactly 500 turns. The solenoid energization is thereupon instantly interrupted, and the fuel flow from spout 27 ceases, being directly shut oi by the valve 26. v
The calibration fuel flow for each test run is thus the output of the pump section 37-1 under test, at a recorded rack setting, for the 500 strokes or pump plunger actua tions. This fuel flow is collected in a graduated beaker 23 placed under spout 27 during the test runs. Beaker 28 is shown in enlarged view in FIG. 2. It is conical, and at its bottom has expanded scale readings for the smaller volumes. Beaker 28 is held in a suitable carrier.
The calibrator 20 contains a test cycle controller schematically indicated in dotted lines at 30. Controller 30 initiates the energization of solenoid valve 26 at the start of each test-run, and automatically deenergizes the valve 26 upon the subsequent completion of a preset number of pump-section strokes, e.g. at 500 strokes. Controller 30 comprises a mechanical r.p.m. counter, with a switch that is tripped when a preset count is reached. The counter is coupled to tachometer take-olf gears 31 in proper ratio to count pump strokes, i.e. its camshaft r.p.m.
The gearing 31 output is coupled to controller 30 and its counter through a shaft indicated schematically by dotted line 32. The controller 30 has an external power line connection .33, and with the counter switch controls the precise energization and deenergization of solenoid valve 26 through control leads indicated by dotted line 34. Calibrator 20 may take other forms, as stated hereinabove.
T he pump sections 37 are calibrated in any order, one at a time. These are checked-out as to fuel volume discharged during exactly say 500 strokes, regardless of the engine speed. It is preferable that the engine r.p.m. be reasonably uniform during a test run; which condition generally prevails for the preset rack settings of each run. T-he first calibration of a pump section e.g. 37-1 at low speed idling for the engine in neutral shift is performed with control valve 46 turned to zero bleed-olfg the rack 40 being at a low setting. The temperature at 29 and engine r.p.m. at 23 are recorded.
The engine is run at least until the spill-over from solenoid valve 26 occurs to denote afull chamber 24. The lines 54 should be full too, which condition may readily be checked by permitting fuel to ow through valve 45 and observing discharge through spill-out tube 47. Once the tests are initiated, only occasional checking of cha-mber y24 and lines 54 fuel-full condition is necessary, as there is negligible leakage.
A typical low-rack idling speed for the HP. truck engine referred to hereinabove is 500 r.p.m., with the pump making 250 strokes per minute. The controller 30 is usually provided with a start switch S.S. Pressing switch S.S. serves to simultaneously actuate solenoid valve 26 to divert fuel into calibration spout 27 and beaker 2S, and to energize a clutch that initiates the counter in controller 30.
The full fuel discharge from the pump section under test 37-1 enters beaker 28 until the counter reaches its preset total of 500. The counter switch thereupon opens to release the solenoid 26. The volume of oil in beaker 28 represents the precise amount of fuel discharge by the vtested pump section for the 500 strokes, for the run conditions as set up. Further rack settings are made successively, as desired, including full load setting of the throttle or accelerator lever of the engine, while the test equipment hereof is connected to a selected pump section, eg. 37-1. Full load setting at intermediate and near top speed tests, are worthwhile performance tests to make.
The fuel discharge volumes, and corresponding rack settings, r.p.m., and temperature are recorded for each run on the pump section 37-1 under calibration. As set forth hereinabove, the bleed-olf control valve 45 is operated by lever 46 to keep the engine from racing as the pump control rack or engine throttle are advanced.
The aforesaid 175 HIP. engine will run with only 12 cc. at full load setting, per cylinder over 500 strokes, and in neutral shift reached only about 1800 r.p.m. It had 40 cc bled-off at lines S4. Under normal operation, such full load high-rack setting would deliver rated power (175 H.P.) at 2100 r.p.m. with 52 cc. per cylinder for 500 strokes supplied by pump 36. Such full fuel delivery to the engine is not practicable for on-engine, neutral shift, inposition pump calibration. The present invention makes this desirable result practical: full fuel delivery by the pump sections, but not to the engine.
The pump is calibrated on a per stroke 'basis and its rack settings, per se, determine its delivery of fuel per stroke. The 500 stroke test results, are thus compared to Standards for that pump. At pump section 37 found to be oiff may be directly readjustedn'in a manner well known in the art, towards its normal, but herein while still on-engine. The readjusted seotionis then recalibrated, until it is shown to be satisfactorily in adjustment. When proper adjustment cannot be'attained While it is thus onengine, one thereupon has learned what is wrong, and the pump is 'then known to require repair on the bench.
FIGS. 3 and 4 illustrate the novel tester system 125 forming the basis of this patent application and its claims.
Y Its function, operation and utility are described in connection with the fuel pump 36 as driven by the diesel engine 51 of'FIG. 1.7Like numerals in these figures denote like components. System 125 is shown connected with fuel pump 36, in calibration of pump section 37-6. Valves 90 and 90 are coupled to the pump sections 37 by line links 53', and to the spray nozzle lines 52. Lines 52 connect with their respective eng-ine nozzles 50, as in system 35. VTest line 38, at section 37-6, feeds into a suitable calibrator 20. The valves 90 and 90' are a four-way type as detailed in the aforesaid patent application. Their extending levers 91 and 9,1 are used to manually preset the mode of operation of the respective valves for the pump testing procedures. Lever 91 of line valve 90', to which test line 38 is coupled, is in the to-test position; while the other levers 91 are in operation position;
Test system 125 utilizes a pulsator 130 that controllably reduces the fuel ow into the engine nozzles 50,
` while permitting the pump rack 40 to be set up to fullload or high rack to perform the calibrating runs. I have discovered that with pulsator 130 the fuel ow per stroke into the high pressure engine nozzles 50 may be controllably reduced from the fuel amounts as normally determined by the rack 40 settings of the pump 36.
In test system 35 described hereinabove, actual bleeding-off or diversion of controlled proportions of pump discharged fuel is utilized. In test system 125 a novel pulsating or pulse-absorbing principle is employed, in the form of a pulsator, the device 130 being an exemplary embodiment thereof. Pulsator 130 operates in a novel and very effective manner to controllably reduce the amount of fuel effectively used by each nozzle 50 per stroke, without actually bleeding-olf and/or spilling-o fuel. Bleed-olf system 35 employs fuel spill-off tube 47. There is no counterpart thereof in pulsator system 125.
The pulsator 130 is provided with input couplings 131-1, 131-2 131-6; one for each pump section 37. These input couplings 131 are directly connected to the line valves 90 by individual lines 133. Lines 133 are designed to conduct fuel oil at the high pressures involved herein, and may be of stiff or exible construction. Their length need be only of the order of one foot, as pulsator 130 Ymay be positioned near the pump 36 being tested. Lines 33 cannot into their respective lines valves 90.
The exemplary pulsator 130 is shown in enlarged crosssection in FIG. 4. Pulsator device 130 comprises a body composed of three cylindrical sections 135, 136, 137. Lower section 135 contains a central cylindrical chamber 138 within which a piston 140 operates. Piston 140 is a cylindrical head with piston rings that ride with a close high-pressure seal along the vertical walls ofchamber 138. Central section 136 is coextensive with section 135, joined therewith across threads 137', and caps'chamber 138. A central shaft 141 carries piston head 140, and operates through a central aperture in section 136.
'I'he upper portion 139 of section 136 is formed with a central cavity 142 that contains the resilient means to be described. The cap section 137 is variably positioned along central portion 139 across respective engaging threads 143, 144. Cap 137 is knurled on its outer surface 145 to facilitate resetting the cap position in'device 130. Each input coupling 131 communicates directly with chamber 138 8 Y through individual connecting bores 132, three of whic appear in FIG. 4. Connecting bores 132 are short, and extend through the base of section 135.
The lines 133 from valves 90 couple directly with the l. Y
input couplings 131 and thereby successively' discharge fuel directly into chamber 138 against the adjacent lower face of piston 140. A removable coupling 146 is inserted between each fixed coupling 131 and its associated line 133. Couplings 146 are preferably of the snap-type variety to facilitate connection of the pulsator to the respective lines 133 of the system( 125. Such straightthrough readily detachable couplings are well known in the art and are shown and described in connection' with FIG. 8 in the aforesaid parent application. When a pump section 37 delivers its measured fuel spurt each stroke to its associated line valve 90, it is at a high pressure, e.g. 2300 p.s.i., as hereinabove explained. Each pump delivery valve at its output 37 and the nozzle 50 input valve are pre-set at such pressure, for operating. Thus each line 133 has this high pressure applied to its contained oil when its respective delivery valve at 37 opens to discharge its Y the operating pump sections 37. The piston 140 is there-V by pressed in turn by the pressured oil in lines 133. Piston head 140 is backed-up by a compression spring 150 exercising a preset counterpressure. Spring is containedwithin cavity 142 by retained cup 151 fastened to the end of shaft 141 by nut'152, and central projection 153 from cap 137.
The adjusted setting of cap 137 on body section 136 determines the counter pressure of spring 150 on the action of piston 140. Cap 137 is adjusted by rotation (across threads 143, 144) manually through knurled head 145. Its setting is readily seen on body scale 154 at its inclined circular edge 155. The setting of cap 137 of pulsator 130 determines the action and reaction of the springpiston combination 140, 150 on'the oil discharges andY discharge pressure, -absorbing a corresponding volume or portion of the fuel otherwise measured for discharge each stroke by the setting of the pump rack 40. The associated engine nozzle 50 directly receives the balance of such measure while the pressure is at its entry valve, e.g. 2300 p.s.i.'At some point in each pump sections delivery stroke, as a result of the resilient piston-spring action of the pulsator 130, the absorbed fuelris either returned to the pump section or inhibited from fully exiting.
The fuel injection pump sections of the aforesaid widely used pumps each have a plunger that contains a helical configuration for metering the amount* of oil discharged per stroke. In adjustments, rotation of the plunger controls the amount of fuel delivered by the section,.thus changing the length of its effective stroke while the lengthof stroke remains the same. When the pressure of the fuel injected by the plunger reaches the preset 2300 p.s.i. at which said engine nozzles are preset to open, fuel enters the associated nozzle Vand to the corresponding engine cylinder. The cushioning or pressure-absorbing action lof the resilient mounted piston 140 in pulsator 130 delays the normal rise or pressure in lines 52 enroute to the nozzles 50.
Thus the nozzles 50 open later in their normal operation cycle, at their preset pressure, e.g. 2300 p.s.i. However, as the pump section plungers are pre-timed in their cyclic operation, they shut off the flow of fuel before the nozzles can obtain their normal amounts. This results in reduced engine power output, as desired, during the test procedure. Adjustment of the setting of cap 137 controls the degree of resilient action of piston 140, and thus the degree of delayed injection and fuel flow to the nozzles 50 and the engine. The piston 140 when cornpressed inwardly of pulsator 130 establishes a back pressure built up against spring 150.
The inward displacement of piston 140 caused by the line pressure in 133 generated by the pump section soon builds up a back-pressure in the line 133. When it reaches the 2300 p.s.i. it results in the corresponding nozzle 50 opening and firing of its cylinder. When fuel ow from the pump section stops, the nozzle valve closes, and the back pressure of piston 140, high but less than the 2300 p.s.i. causes back flow through the pump delivery valve before it shuts. The piston 140 thus returns to its lower pressure position ready for its next excursion upon the successive pump section operation.
Regardless of the theory explanation of its action, I have discovered this pulsation action to be practical and operable over the whole rack 40 range from the pump calibration runs. The pulsator 130 settings remain stable, and provide the same proportionate fuel delivery reduction as preset to allthe operating nozzles 50 and engine cylinders, without secondary injections or back-frings. The engine 51 works smoothly for each test run, and is held under safe control in power and speed for changes in rack 40 settings, up through high rack.
When cap edge 155 is set higher on scale 154, as schematically indicated by raised dotted line cap position 137", spring 150 permits piston 140 to have larger displacements for given pump output pressures. At the higher pump rack settings, the oil spurt volumes increase, -and higher readings on pulsator scale 154 are used for reducing the net fuel ffow per stroke into the nozzles 50. Also, for any given pump rack 40 setting, increasing the cap 137 readings, i.e. raising it to relieve the spring 150 therein, will correspondingly further reduce the fuel input to the engine 51, and thereby slow it down. The actual settings 154, 155 of the pulsator 130 is readily performed manually, and even empirically, in conjunction with the rack setting changes in each test run, as in the system described hereinabove.
It is to be noted that by making the bleed-off lines 54 (of system 35) of high pressure line construction with resilient or somewhat flexible sheathing, some pulsating action of the type described in system 125 is found to occur therein. Such pulsations occur cyclically in these lines, a sheathing pulse foreach fuel spurt discharged into the associated line valve 90. Such resilient bleed-off line vsheathing thereby may be used to provide an individualized pulsator for each operating pump section 37, of minor proportion and fixed in setting. Such fixed pulsator line action is combined with controlled bleed-off action via the bleed-off valves 45, for practical operational control of the engine 51 in the pump 36 tests hereof, :when the pump rack 40 settings are reset, as will now be understood by those skilled in the ait.
The testers of the present invention are very effective in directly determining the efficiency or proper setting and balance of fuel pumps of diesel engines, and their associated governors. This is readily performed, economically of labor and engine (and vehicle) down-time. The fuel pump is not removed for the testing and concomitant adjustments. The most significant tests are under full load condition of the pumps operation, with its control lever or rack correspondingly extended.
F or example, a truck with an engine rated at 2350 rpm. full speed, has its governor start cutting-off fuel settings at that peak speed. Such engine is tested herein at 2000 or 2100 r.p.m. in order to avoid any cut-off action during test runs. Pump rack settings at full load fuel delivery thus hold such setting during the calibration or measuring runs of the selected pump sections. This obviates the above described procedure.
The high-speed full-load (full-rack) test is attained with the testers of the invention as follows: the calibration line 38 of the tester is set up to deliver the fuel from the pump section under test (37-1), to the measuring unit 20, and to the remaining pump sections, to controllably deliver fuel to their associated engine nozzles. The throttle or pump rack is then -gradually moved to higher and higher settings, until the engine speed rea-ches about 2000 r.p.m. The pump fuel delivery, per se, is then further increased through throttle and/ or rack, while the bleed-oliC control 46 of the tester of FIG. 1, or the pulsator setting 154-155, is operated to correspondingly reduce fuel delivery from the pump 36 to the nozzles 50. In this manner the pump rack setting, an-d/ or throttle, is thereby moved towards and finally into full-load position. 'Ihe engine is thereby placed in safe operation, near its full-speed as at 2000 r.p.m. even though its gear shift is in neutral, with no real loading-down or braking. The bleed-off or the pulsator control, in the process herein, inhibits in a controllable manner the fuel ow from the pump sections to the engine nozzles. The selected pump section is arranged to feed the test fuel amount to the measuring unit 20, while engine is controllably held at the high-speed of 2000 r.p.m. during the desired number of strokes, as 250 or 500. The test fuel delivery, in beaker 28, is thereupon compared to the Standard for the particular pump, as from a Service Chart. The other pump sections are similarly tested, in turn. I have found that, in practice, holding the engine speed herein between 1900 and 2100 r.p.m. during any "2000 rpm. test run, provides satisfactory and repetitive results.
A further useful test series on a fuel pump, in-position on its diesel engine, is at full-load and at intermediate-speed, as at 1500 r.p.m. Such test is particularly indicated when the associated governor is of the droopscrew type, and corresponds to its actuation in a truck on up-hill full-load operation at lower-than-full speed, as at 1500 r.p.m. The test procedure for such run is similar to that herein described for the 2000 r.p.m. series, attaining the 1500 r.p.m. with full-rack setting of the pump control, properly bled-off or pulsated therefor. In practice, maintaining a 1400-1600 rpm. range during the test runs, gives satisfactory readings and results.
Ready interpretation of these tests, as to the adjustment and balance of the fuel pump sections and/or itS governor, permit such direct adjustments as are feasible on-engine. Occasion for the removal of the pump and/ or governor, through the invention in-position testing, iS minimized. Further, the testing of the rotary type or distributor-type pumps is effective and simple with the invention testers. The testing of one pump section thereof in practice provides results as to the adjustment, delivery, and operation for all of the pump.
Although the present invention has been illustrated and described in connection with a preferred embodiment thereof, it is to be understood that variations and modifications of the system and its component parts, as well as its applications, may be made that fall within the broader spirit and scope of this invention, as set forth in the following claims.
1. In a system for in-position testing the discharge of fuel from the individual output sections of the injection pump coupled by lines to the plural spray nozzles of a diesel engine and driven thereby, and wherein the setting of -a unitary control element adjusts the volume of fuel discharged per stroke in succession by each pump section for its associated spray nozzle: a fuel volume measuring unit; means fro conducting the fuel output of a selected for testing pump section to said measuring unit;
and control means for reducing fuel output to the nozzles from the remaining associated sections of the pump, and thereby correspondingly substantially uniformly control the reduced amount of fuel entering their -respectivespray nozzles of the engine for its operation of the pump during its in-position testing as compared with the basic fuel output from said sections normally determined by the indicated control element setting, said control means comprising pulsatable means actuated by the successive fuel discharges by the remaining pump sections, whereby the engine is operatively fueled by said remaining pump sections while the selected pump secl tion is being tested.
2. A system as claimed in claim 1, further including auxiliary lines for hydraulically connecting said pulsatable means with the remaining pump sections to control the rate of fuel reduction to their respective nozzles.
3. Ina. system for testing the delivery of fuel from the individual output sections of the 'injection pump coupled to t-he plural spray nozzles of a diesel engine and driven thereby, and wherein each pump section is coupled to a unitary control element the setting of which adjusts the volume of fuel delivered per stroke in succession by each pump section for its associated spray nozzle in successive spurts: a fuel volume measuring unit; means for conducting the fuel output of a selected for testing pump section to said measuring unit; and control means for inhibiting fuel output to the nozzles from each of the remaining! associated sections of the pump, and thereby correspondingly controllably reduce the amount of fuel entering their respective spray nozzles of the engine lfor its operation of the pump during its testing as compared with the basic fuel output from said sections normally determined lby the indicated control element setting, said control means comprising pulsatable meansvactuated by the successive fuel discharges by the remaining pump sections, whereby the engine is operatively fueled by said remaining pump sections While the selected pump section is being tested.
4. A system as claimed in claim 3, further including auxiliaryA lines for hydraulically connecting said pulsatable means with the remaining pump sections to control t-he rate of fuel reduction to their respective nozzles.
5. In a system for in-position testing the delivery of fuel from individual output sections of the injection Ipump coupled by lines to the plural spray nozzles of a diesel engine and driven thereby, and wherein each pump section is controllable by the setting of a unitary control element which adjusts the volume of fuel discharged per stroke in succession by each pump section at high pressure for its associated spray nozzle: a unit for measuring the fuel output of a pump section selected for testing; means for conducting the 4fuel output of the selected pump section to said measuring unit; and unitary control means for reducing fuel output to the nozzles from each of the remainin-g associated sections of the pump, and thereby correspondingly substantially uniformly reduce the amount of fuel entering their respectiveV spray nozzles of the engine for its operation of the pump during its in-position testing as compared with the basic fuel output from said sections normally determined by the indicated control element setting, said control means comprising vpulsatable means containing a resilient element actuated by the successive fuel discharges of the remaining pump sections, whereby effectiveoperation of the engine and pump together is provided during test runs on the selected pump section with the engine being Y fueled through said remaining pump sections.
6. A system as claimed in claim 5, further including auxiliary lines for hydraulically coupling the remaining pump sections with said pulsatalble means, and means for adjusting the resilient action and reaction of said pulsat'able means to control the rate f fuel reduction to t-he respective nozzles. Y
7. In a system for irl-position testing the discharge of fuel from the individual outputlsections of the injection pump coupled by lines to the plural spray nozzlesV of a diesel engine and driven thereby, and'wherein each pump section is controllable by the setting of a unitary control rack which adjusts the volume of fuel discharged per stroke in succession by each pump section vat high pressure for its associated spray nozzle in successive spurts: Va fuel volume measuring unit; means for conducting the full fuel output of a selected for testing pump section to said measuring unit; individual means for hydraulically coupling to the fuel output of the remaining sections of the pump and to their respective spray nozzle lines; and unitary control means for altering the Vfuel output from each of said remaining pump sections to correspondingly reduce the amount of fuel entering their associated spray nozzles of the engine to an amount suflicient for its operation of the pump during its in-position testing as compared with the'basic fuel output from said sections for an idicated rack setting, said control means including individual auxiliary lines extending from the hydraulic coupling means and thereby establish an hydraulic circuit from the fuel output of each of said `remaining pump sections to the inputs of their associated spray nozzles as well as to said control means, said control means comprising pulsatable means having a piston and spring mechanically coupled thereto actuated by the successive fuel discharges by the remaining pump sections, whereby effective and safe operation of the engine and pump together is provided during test runs on the selected pump section over the range of settings of the pump control rack with the engine being fueled through said remaining pump sections.
8. A Vsystem as claimed in claim 7, further including auxiliary lines for hydraulically coupling the remaining pump sections with said piston, and means for adjusting the resilient action and reaction of said piston to control Y the rate of fuel reduction to said respective nozzles.