The range of power outputs for diesel engines with in-line fuel-injection pumps extends from 10 to 200 kW per cylinder. Various pump design variations allow such a wide range of power outputs to be accommodated. The designs are grouped into series whose engine output ranges overlap to some degree. Pump sizes A, M, MW and P are produced in large volumes (Figure 1).
There are two different designs of the standard in-line fuel-injection pump:
the open-type design of the Type M and A pumps with a cover plate at the side, and the closed-type design of the Type MW
and P pumps in which the plunger-and- barrel assemblies are inserted from the top. For even higher per-cylinder outputs, there are the pump sizes P10, ZW, P9 and CW. There are two ways in which the plunger-and- element assemblies can be supplied with fuel (Figure 2):
With the longitudinal scavenging (a), fuel flows from one plunger-and-barrel assembly to the next in sequence.
With the crossflow scavenging (b), the plunger-and-barrel assemblies are supplied individually from a common supply channel. In this way, the fuel-delivery termination pressure does not affect the adjacent cylin- der. This achieves tighter quantity tolerances and more precise fuel proportioning.
28 Type PE standard in-line fuel-injection pumps Design variations
Fig. 2 a Longitudinal scavenging b Crossflow scavenging (Type P-8000 pump) M A MW P1…3000 P7100…8000 5 cm
Comparison of in-line fuel-injection pump sizes (sectional view)
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U M K0803-1Y a bPump element flushing patterns
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S M K1 8 1 4YType PE standard in-line fuel-injection pumps 1978 diesel speed records 29
1978 diesel speed records
In April 1978 the experimental Mercedes-Benz C111-III set nine world speed records, some of which still stand today, and eleven interna- tional class records. Some of those records had previously been held by gasoline-engine cars.
The average speed of the record attempts was approximately 325 kph. The highest speed reached was measured at 338 kph. The average fuel consumption was only 16 l /100 km.
These considerable achievements were made possible primarily by the highly streamlined plastic body. Its aerodynamic drag coefficient of 0.195 was sensationally low for the time.
The car was powered by a 3-liter, five-cylinder in-line diesel engine with a maximum power output of 170 kW (230 bhp). That meant that it was twice as powerful as its standard pro- duction counterpart. The maximum torque of 401 Nm was produced at 3,600 rpm. This per- formance was made possible by a turbocharg- er and an intercooler. At the engine’s nominal speed, the turbocharger was rotating at 150,000 rpm.
Precise fuel delivery and metering was provided by a Bosch Type PE...M in-line fuel-injection pump
Engine compartment of the Mercedes-Benz C111-III
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N M M0598Yæ
N M M0599YSize M fuel-injection pumps
The size M in-line fuel-injection pump (Fig- ures 3 and 4) is the smallest of the Series PE pumps. It has a light-metal (aluminum) body that is attached to the engine by means of a flange.
The size M pump is an open-type in-line fuel-injection pump which has a cover plate on the side and the base. On size M pumps, the peak injection pressure is limited by the pump to 400 bar.
After removal of the side cover plate, the de- livery quantities of the plunger-and-barrel assemblies can be adjusted and matched to one another. Individual adjustment is ef- fected by moving the position of the clamp blocks (Figure 4, Item 5) on the control rack (4). When the fuel-injection pump is running, the control rack is used to adjust the position of the pump plungers and, as a result, the delivery quantity within design limits. On the size M pump, the control rack consists of a round steel rod that is flatted on one side. Fitted over the control rack are the slotted clamp blocks. Together with its control sleeve, the lever (3), which is rigidly attached to the control sleeve, forms the mechanical link with the corresponding clamp block. This arrange- ment is referred to as a rod-and-lever control linkage.
The pump plungers sit directly on top of the roller tappets (6). LPC adjustment is achieved by selecting tappet rollers of differ- ent diameters.
The size M pump is available in 4, 5 and 6 cylinder versions, and is suitable for use with diesel fuel only.
30 Type PE standard in-line fuel-injection pumps Design variations
Fig. 4 1 Delivery valve 2 Pump barrel 3 Control-sleeve lever arm 4 Control rack 5Clamp block 6 Roller tappet 7 Camshaft 8 Cam 1 2 3 4 5 6 7 8
Type M in-line fuel-injection pump (sectional view)
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U M K043 7 -1YType M in-line fuel-injection pump (external view)
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Size A fuel-injection pumps
The size A in-line fuel-injection pump (Fig- ures 5 and 6) is the next size up from the size M pump and offers larger delivery quantities as a result.
It has a light-metal housing and can be ei- ther flange-mounted to the engine or attached by means of a cradle mounting.
On the size A fuel-injection pump, which is also an open-type design, the pump barrel (Figure 6, Item 2) is inserted directly into the aluminum body from above. It is pressed by the pressure-valve holder against the pump housing via the pressure-valve support. The sealing pressures, which are considerably higher than the hydraulic delivery pressures, must be withstood by the pump housing. For this reason, the peak pressure for a size A pump is internally limited to 600 bar. In contrast with the size M pump, the size A pump has an adjusting screw (7) for setting the plunger lift to port closing. This simpli- fies the process of adjusting the basic setting. The adjusting screw is screwed into the roller tappet and fixed by a locking nut.
Another difference with the size M pump is the rack-and-pinion control linkage instead of the rod-and-lever arrangement. This means that the control rack is replaced by a rack (4). Clamped to the control sleeve (5) there is a control-sleeve gear. By loosening the clamp bolt, each control sleeve can be rotated rela- tive to its control-sleeve gear in order to equalize the delivery quantities between in- dividual plunger-and-barrel assemblies.
With this design of pump, all adjustments must be carried out without the pump run- ning and with the housing open. A cover plate is positioned on the side of the pump housing and provides access to the valve- spring chamber.
Size A pumps are available in versions for up to 12 cylinders and, in contrast with the size M models, are suitable for multifuel operation.
Type PE standard in-line fuel-injection pumps Design variations 31
Fig. 6 11 Delivery valve 12 Pump barrel 13 Pump plunger 14 Control rack 15Control sleeve 16 Plunger spring 17 Adjusting screw 18 Roller tappet 19 Camshaft 10 Cam 1 2 3 4 5 6 7 8 9 10
Type A in-line fuel-injection pump (sectional view)
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K0439-1Y
Type A in-line fuel-injection pump (external view)
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Size MW fuel-injection pumps For higher pump outputs, the size MW in-line fuel-injection pump was developed (Figures 7 and 8).
The MW pump is a closed-type in-line fuel-injection pump which has a peak pres- sure limited to 900 bar, it is a lightweight metal design similar to the smaller models, and is attached to the engine by a baseplate, flange or cradle mounting.
Its design differs significantly from that of the Series M and A pumps. The main distin- guishing feature of the MW pump is the barrel-and-valve assembly that is inserted into the pump housing from above. The barrel-and-valve assembly is assembled out- side the housing and consists of the pump barrel (Figure 8, Item 3), the delivery valve (2) and the pressure-valve holder. On the MW pump, the pressure-valve holder is screwed directly into the top of the longer pump barrel. Shims or spacers of varying thicknesses are fitted between the pump housing and the barrel-and-valve assembly to achieve LPC adjustment. The uniformity of fuel delivery between the barrel-and-valve assemblies is adjusted by rotating the barrel- and-valve assembly from the outside. To achieve this, the flange (1) is provided with slots. The position of the pump plunger is not altered by this adjustment.
The MW pump is available with the various mounting options in versions for up to 8 cylinders. It is suitable for diesel fuel only. MW pumps are no longer used for new engine designs.
32 Type PE standard in-line fuel-injection pumps Design variations
Fig. 8
1 Pump unit mounting flange 2 Delivery valve 3 Pump barrel 4 Pump plunger 5Control rack 6 Control sleeve 7 Roller tappet 8 Camshaft 9 Cam 1 2 3 4 5 6 7 9 8
Type MW in-line fuel-injection pump (sectional view)
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U M K044 1-1YType MW in-line fuel-injection pump (external view)
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Size P fuel-injection pump
The size P in-line fuel-injection pump was similarly developed for higher pump outputs (Figures 9 and 10). Like the MW pump, it is a closed-type fuel-injection pump and is at- tached to the engine by its base or by a flange. On size P pumps for peak internal pressures of up to 850 bar, the pump barrel (Figure 10, Item 4) is inside an additional flange bushing (3) in which there is an internal thread for the pressure-valve holder. With this design, the sealing forces do not act on the pump housing. LPC adjustment on the P pump takes place in the same way as on the MW pump.
In-line fuel-injection pumps with low injec- tion pressures use conventional fuel gallery flushing whereby the fuel passes through the fuel galleries of the individual barrel-and valve assemblies one after the other from the fuel inlet to the return outlet, traveling along the pump longitudinal axis (longitudinal scav- enging). On size P pumps of the type P 8000, which are designed for injection pressures at the pump of 1,150 bar, this flushing method inside the pump would result in a significant temperature difference in fuel temperature (as much as 40 °C) between the first and the last cylinder. Consequently, different quanti- ties of energy would be injected into the in- dividual combustion chambers of the engine (the energy density of the fuel decreases with increasing temperature and the associated increase in volume). For this reason, this type of fuel-injection pump has crossflow scavenging (i.e. at right angles to the pump longitudinal axis) whereby the fuel galleries of the individual barrels are isolated from one another by flow throttles and are flushed in parallel with fuel at virtually identical tem- peratures.
The P-type pump is produced in versions for up to 12 cylinders and is suitable both for diesel-only and for multifuel operation.
Type PE standard in-line fuel-injection pumps Design variations 33
Fig. 10 1 Pressure-valve holder 2 Delivery valve 3 Flange bushing 4 Pump barrel 5Control rack 6 Control sleeve 7 Roller tappet 8 Camshaft 9 Cam 2 1 4 3 5 6 7 8 9
Type P in-line fuel-injection pump (sectional view)
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K0443-1Y
Type P in-line fuel-injection pump (external view)
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Size P10 fuel-injection pump
The size P10 in-line fuel-injection pump is the smallest of the models described below for larger diesel engines such as are used for off-road applications, fixed installations, construction and agricultural machinery, specialized vehicles, railway locomotives and ships. It is mounted on the engine by means of a baseplate.
The peak injector pressure is limited to approx. 1,200 bar.
The closed-type light-metal body (Figure 12, Item 13) holds the barrel-and-flange elements that are inserted from the top. They consist of a pump barrel (5), a constant-pressure valve and a pump plunger (12). They are held in position by stud bolts (3). A pres- sure-valve holder (1) seals the constant-pres- sure valve. As a result, the pump housing is not subjected to sealing stresses. Fitted directly in the pump barrels are impact-deflector screws (4) which protect the pump housing from damage caused by high-energy cutoff jets at the end of the delivery stroke. On the control sleeve (8) there are two link arms with thin cylindrical end lugs which locate in mating slots on the control rack (6).
For balancing the delivery quantity be- tween plunger-and-barrel assemblies, the pump barrels have slotted mounting holes on their flanges. This allows the pump bar- rels to be suitably adjusted before they are tightened in position. The LPC is adjusted by inserting shims or spacers (2) of varying thicknesses between the pump barrels and the pump housing. To make them easier to replace, the shims are slotted so that they can be inserted from the side.
In order to remove a roller tappet (10) when servicing the pump, the correspond- ing pump barrel must first be removed. The spring seat (7) above the plunger spring (9) is then pressed downwards. A retaining spring (11) holding the spring seat then releases it. The spring seat, con- trol sleeve, plunger spring, pump plunger and roller tappet can then be removed from above.
34 Type PE standard in-line fuel-injection pumps Design variations
Fig. 12 11 Constant-pressure valve socket 12 Shims 13 Stud bolts 14 Impact-deflector screw
15Pump barrel with mounting flange 16 Control rack 17 Spring seat 18 Control sleeve 19 Plunger spring 10 Roller tappet 11 Spring ring 12 Pump plunger 13 Housing 14 Camshaft 1 2 3 4 5 6 7 8 11 14 13 12 9 10
Type P10 in-line fuel-injection pump (sectional view)
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S M K1 844YType P10 in-line fuel-injection pump (external view)
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S M K1 843YTo refit these components, the plunger spring is compressed using the spring seat and the retaining spring which is snapped into position in the pump housing using a special device.
The camshaft runs on roller elements in the pump housing at each end. In order to obtain a high degree of rigidity, it is also supported by one or two half-shell plain bearings.
The size P10 fuel- injection pump is con- nected to the engine lube-oil circuit. A throttle bore determines the rate of oil flow. The fuel galleries of the individual plunger- and-barrel assemblies are interconnected and fuel circulates through the pump in a longitudinal direction (longitudinal scav- enging). The presupply pump is usually ei- ther a gear pump driven by the engine or an electric fuel pump. For effective supply of the fuel-injection pump (and therefore effi- cient pump cooling), its delivery rate is sev- eral times the required fuel quantity.
Size P10 fuel-injection pumps are pro- duced in versions for 6, 8 and 12 cylinders. The standard design is for diesel fuel only, with a special version available for multifuel operation.
Size P9 fuel-injection pump
The size P9 in-line fuel-injection pump is more or less identical in design to the P10 pump. However, it is somewhat larger and therefore positioned between the ZW and CW models.
The P9 fuel-injection pump has a closed- type light-metal housing. As with the P10, the peak nozzle pressure is limited to
approx. 1,200 bar. It is attached to the engine by means of a cradle mounting. It is pro- duced in versions for 6, 8 and 12 cylinders. The pump delivery quantity is controlled by a hydraulic or electromechanical governor provided by the engine manufacturer.
Size ZW fuel-injection pump
The size ZW in-line fuel-injection pump (Figure 13) has an open-style light-metal housing. The pump is attached to the engine by means of a cradle mounting. The peak nozzle pressure is limited to 950 bar.
The pressure-valve holder (Figure 14 overleaf, Item 1) screwed into the pump housing (18) provides the seal between the delivery valve and the pump barrel (2) as well as transmit- ting the hydraulic forces from the plunger. A fixing bolt (14) holds the pump barrel in position.
Two hardened impact-deflector screws (3) fitted in the pump housing opposite the control ports for each cylinder protect the pump housing from damage caused by the high-energy cutoff jet at the end of the delivery stroke.
The delivery quantity is controlled by means of a control rack in the form of a rack (4). This meshes with the control-sleeve gear that is clamped to the control sleeves (6).
For balancing the delivery quantities of the individual plunger-and-barrel assemblies, the clamp bolts (15) are loosened. Each con- trol-sleeve gear can then be rotated relative to its control sleeve. The clamp bolts are then retightened.
Type PE standard in-line fuel-injection pumps Design variations 35
Type ZW in-line fuel-injection pump (external view)
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S M K1 845YLPC adjustment takes place by fitting or replacing the LPC disk (9) or a screw in the roller tappet (10).
For the purposes of removing the
camshaft (11), the roller tappets can be held at their upper limit of travel by a retaining screw (17) fitted in the side of the pump housing. The camshaft runs on roller ele- ments. For larger numbers of cylinders, there may also be one or two half-shell plain bearings in addition.
The presupply pump used may be a recipro- cating piston pump which is flange-mounted on the side of the fuel-injection pump or a separate ring-gear pump or electric fuel pump. The fuel-injection pump is lubricated by the engine lube-oil circuit.
Size ZW fuel-injection pumps are available for engines with 4...12 cylinders. They are suitable for operation with diesel fuel. Fuel-injection pumps with the designation ZW(M) are designed for multifuel operation. Size CW fuel-injection pump
The size CW in-line fuel-injection pump completes the top end of the Bosch in-line fuel-injection pumps range. The typical area of application for this model is on heavy- duty and relatively slow-revving marine engines and off-highway power units with nominal speeds of up to 1,800 rpm and power outputs of up to 200 kW per cylinder.
Even the 6-cylinder version of this fuel- injection pump with its closed-style pump housing made of nodulized cast iron weighs around 100 kg – this is roughly the weight of medium-sized car engine.
The pump is attached to the engine by eight bolts through its base.
The peak injection pressure is limited to approx. 1,000 bar.
The sealing and retention forces of the pump barrels with their plunger diameters of up to 20 mm are transferred to the pump housing by means of four strong clamp bolts
(Figure 15, Item 1).
36 Type PE standard in-line fuel-injection pumps Design variations
Fig. 15 1 Clamp bolt 2 Impact-deflector screw 2 Screw cap Fig. 14 11 Constant-pressure valve socket 12 Pump barrel 13 Impact-deflector screw 14 Control rack
15Control rack guide screw 16 Control sleeve 17 Pump plunger 18 Plunger spring 19 LPC disk 10 Roller tappet 11 Camshaft 12 Oil-level checking plug 13 Oil filler plug 14 Pump-unit fixing screw 15Clamp bolt 16 Cover plate 17 Retaining screw 18 Pump housing 12 10 11 17 9 8 7 5 6 4 3 2 1 16 14 15 18 13
Type ZW in-line fuel-injection pump (sectional view)
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S M K1 846Y 3 2 1Type CW in-line fuel-injection pump (external view)
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S M K1 84 7YThe control rack is in the form of a rack. Balancing of the delivery quantity between plunger-and-barrel assemblies is achieved with the aid of small orifices in the side of the pump housing. They are sealed by screw caps (3). LPC adjustment is by inserting shims of varying thicknesses between the roller tappets and the pump plungers. Fuel supply to the fuel-injection pump is provided by a gear pump driven by the engine or an electric fuel pump.
The fuel-injection pump is controlled by a hydraulic or electromechanical governor provided by the engine manufacturer.
The pump is produced in 6, 8 and 10- cylinder versions and is suitable for use with diesel fuel.
In-line fuel-injection pumps for special applications
In addition to their use with internal com-