CN111279063B

CN111279063B - High pressure pump/crankshaft setup method

Info

Publication number: CN111279063B
Application number: CN201880068599.9A
Authority: CN
Inventors: T·雷德林格尔; C·伯格
Original assignee: Renault SAS
Current assignee: New H Power Transmission System Holdings Ltd
Priority date: 2017-11-08
Filing date: 2018-11-08
Publication date: 2022-06-17
Anticipated expiration: 2038-11-08
Also published as: CN111279063A; FR3073256A1; WO2019092085A1; EP3707366A1; RU2020117172A3; RU2020117172A; FR3073256B1

Abstract

An arrangement (10) for setting a high-pressure fuel pump (300) of a heat engine, the arrangement comprising: a crankshaft (210) housed in a casing of the engine and comprising an oval sprocket (200) rigidly connected to one end of the crankshaft rotating towards a dispensing face (DI) of the engine; a camshaft (250) rotated by the crankshaft using a drive train around an oval sprocket; said fuel supply pump comprising an actuating shaft (302) whose axis is parallel to the axis of the crankshaft and whose one end is rotated by the end of the camshaft turned towards the coupling surface (AC) of the engine opposite the dispensing surface (DI), characterized in that the setting means (10) are able to set the fuel pump with respect to the crankshaft and comprise control means (11) for controlling the angular position of the crankshaft and control means (12) for controlling the position of the high-pressure pump with the same precision.

Description

High pressure pump/crankshaft setup method

Technical Field

The present invention relates to a heat engine or an internal combustion engine of a motor vehicle.

The invention relates more particularly to combustion engines comprising a high-pressure pump for supplying and boosting a fuel injection system.

The invention relates more specifically to a method for setting a high-pressure fuel pump by means of a crankshaft, which is mounted on one end of a camshaft of a combustion engine.

Background

In a known manner, internal combustion engines, and in particular direct injection engines (i.e., engines in which the fuel injectors open directly into the combustion chamber), have a high-pressure fuel pump that enables pressurized fuel to flow through the fuel rail of the injector. This fuel injection technique is well known in diesel engines, but may also be used in spark ignition engines (also referred to as gasoline engines).

Advantageously, the engine can drive the high-pressure pump, which in turn enables the engine to be fueled. To this end, the high pressure pump may have an actuating shaft, the rotation of which actuates the pumping means, which is typically a piston moving within a cylinder.

The actuating shaft of the pump is provided with an actuating sprocket that drives the actuating shaft. The actuation sprocket and therefore the actuation shaft of the high-pressure pump can be rotated by a belt or chain arranged on one side of the satellite face of the engine (also called the dispensing face of the engine), which links the crankshaft of the engine to a camshaft or possibly camshafts designed to actuate the valves, or by another gear constrained to rotate with the rotating shaft. According to the present invention, in order to reduce the size of the engine, the high-pressure pump is disposed at one end of the camshaft on the side of the driving surface opposite to the attaching surface of the engine.

In certain pump types, incorrect positioning of the high pressure pump relative to the crankshaft causes ripple forces in the belt of the overall system, which results in induced torque in the pulley, which adversely affects system timing reliability. In a known manner, the high-pressure pump may be driven directly, for example by a cam constrained to rotate with the shaft of the crankshaft. In this case, no specific means for ensuring accurate indexing or setting of the high-pressure pump relative to the crankshaft of the engine is required.

However, in other examples where the high pressure pump is driven, for example, by a transmission (which in the embodiments set forth below includes a belt or drive chain connecting a drive sprocket rigidly connected to the crankshaft to the actuation shaft of the high pressure pump), the resulting fluctuations may cause the dispensing chain or belt to break, potentially damaging the engine or damaging the bearings or mounting of the shaft (pump shaft, crankshaft, camshaft), creating a risk of failure or generating noise and vibration.

Furthermore, a correct arrangement between the high pressure pump and the engine is necessary to ensure that the forces generated by the pump do not disturb the engine at engine start-up, and in particular an optimum arrangement is required to enable the engine to start systematically in a short time (typically within two top dead centre of the cycle of the engine for a four cylinder engine). This is necessary for motor vehicle applications provided with an automatic engine stop and start system.

Typically, the drive sprocket of the crankshaft is conventional and circular. In order to reduce the amplitude of the fourth harmonic of the engine amplified by the pump's pressure pulsations, an oval sprocket with four lobes was placed in the system in place of the circular drive sprocket to also generate the H4 load. These loads are generated in phase opposition to the H4 signal generated by the high pressure pump to reduce the amplitude of the engine's fourth harmonic.

It is then necessary to ensure accurate positioning between the high-pressure fuel pump and the engine, in particular with respect to the crankshaft.

The present invention aims to overcome these problems and it is an object of the present invention to provide an apparatus and a method for arranging a high-pressure fuel pump with respect to a heat engine incorporating said fuel pump, which enables the accuracy of such an arrangement to be improved.

Disclosure of Invention

The invention relates more particularly to a setting device for a high-pressure fuel pump of a heat engine, comprising:

a crankshaft housed in the casing of the engine and containing an oval sprocket constrained to rotate with one end of the crankshaft turned towards the dispensing face of the engine,

a camshaft driven in rotation by a crankshaft using a transmission system around an oval sprocket,

said fuel supply pump comprises a shaft whose axis is parallel to the axis of the crankshaft and whose one actuating end is constrained to rotate with an end of the camshaft turned towards a coupling face of the engine opposite the dispensing face,

characterised in that the engine has setting means for the fuel pump relative to the crankshaft, the setting means having means for controlling the angular position of the crankshaft and means for controlling the position of the high pressure pump, thereby providing equal accuracy.

Advantageously, the heat engine has a setting device between the high-pressure pump and the crankshaft, which is designed to take into account all the elements of the operating chain of the engine, namely a camshaft driven by a belt or chain and an actuating sprocket driving the pump through said camshaft. Then, a direct arrangement is made between two elements of the engine (in particular the crankshaft and the high-pressure fuel pump) using means for controlling the angular position of the crankshaft and means for controlling the angular position of the actuation shaft of the pump, these means providing a high and equal accuracy.

According to other features of the invention:

the means for controlling the angular position of the crankshaft and the high-pressure fuel pump are of the same type.

Advantageously, the two control means are of the same type, providing the same control accuracy.

The means for controlling the angular position of the crankshaft and of the high-pressure pump have a hole which crosses the housing surrounding the crankshaft and the housing surrounding the actuation end of the pump, respectively, the axis of the hole being orthogonal to the axis of the crankshaft and to the axis of the shaft of the pump.

The through hole is designed to accommodate a gauge.

The gauge is a leak gauge.

Advantageously, the means for controlling the angular position of the crankshaft and the means for controlling the angular position of the high-pressure pump comprise a hole which crosses the housing containing the crankshaft or the actuating end of the high-pressure pump to enable the insertion of a gauge, which is a well-known accessory for setting, in particular for setting the engine distribution. The axis of the through hole is orthogonal to the axis of the crankshaft and to the axis of the actuating shaft of the pump.

The gauge is a leaky gauge that achieves better optimum accuracy than using conventional gauges.

The crankshaft and the high-pressure pump each have a flat face designed to be orthogonal to the axis of the hole of the housing traversing the crankshaft and to the axis of the hole of the housing traversing the actuation end of the pump, respectively.

Advantageously, the crankshaft and the high-pressure pump each have a flat face designed to be orthogonal to the axis of the hole of the housing traversing the crankshaft and to the axis of the hole of the housing traversing the end of the actuation shaft of the high-pressure pump, so as to ensure the sealing of the gauge in bearing contact with said flat faces.

The flat face of the crankshaft is carried by a flange of an arm rigidly connected to the crankshaft.

Advantageously, the flat face of the crankshaft is carried by a flange of a crank arm rigidly connected to the crankshaft. Thus, the flange is constrained to rotate with the crankshaft.

The flat face of the end of the actuation shaft of the pump is carried by a tooth rigidly connected to an actuation sprocket rigidly connected to the end of the actuation shaft of the high-pressure pump.

Advantageously, the flat face of the end of the pump actuating shaft is carried by a tooth rigidly connected to the actuating sprocket, said tooth being substantially parallelepiped-shaped and axially aligned, for example, with the tooth of the actuating sprocket.

The invention also relates to a method for setting a high-pressure fuel supply pump by means of a crankshaft of a heat engine of a motor vehicle, said method comprising a control step for determining an angular setting position of the pump by means of the crankshaft.

-the method comprises the steps of:

-bringing the gauge into contact with the flat face of the parallelepiped-shaped element of the actuation sprocket of the high-pressure pump,

-bringing the gauge into contact with the crankshaft at top dead center.

Drawings

Further features and advantages of the invention will become clear from reading the following description of a particular embodiment of the invention, provided as a non-limiting example and illustrated in the accompanying drawings, in which:

figure 1 is a schematic view of a heat engine dispensing module,

figure 2 is a schematic view of a drive sprocket rigidly connected to the end of a crankshaft according to the invention,

FIG. 3 is a schematic view of a device for controlling the angular position of the actuation shaft and of the crankshaft of a high-pressure fuel pump,

figure 4 is a schematic view of a device for controlling the setting of the high-pressure pump,

fig. 5 is a schematic view of a device for controlling the setting of the high-pressure pump relative to the crankshaft.

Detailed Description

In the following description, the same reference numerals are used for the same portions or portions having similar functions.

In a known manner, an internal combustion engine of a motor vehicle has combustion chambers in the housing of the engine, each combustion chamber being delimited by a cylinder, a piston and a cylinder head wall.

Fuel and air are typically injected into the combustion chamber from orifices formed in the cylinder head wall. Fuel is delivered to the injectors through a primary rail formed in the cylinder head for injection into each of the chambers.

The pistons are linked to a crankshaft 210 by connecting rods. The piston is driven to slide back and forth along the axis of the cylinder to drive the crankshaft in rotation, having a compression phase in which it slides to reduce the volume of the combustion chamber, and a combustion/expansion phase following the explosion of the air-fuel mixture in said combustion chamber, thereby generating pulsations in the rotation of the crankshaft. This phase alternation leads to an uneven rotation (hypoclisme) which is manifested as an uneven crankshaft speed.

The uneven rotation is transmitted to a transmission system comprising a distribution chain with a camshaft and accessories driven by the engine, such as an alternator, an air conditioning compressor and a belt.

Fig. 1-5 show the distribution chain from the crankshaft 210 to the high pressure pump 300.

The dispensing chain generally has, for example, a drive sprocket 200 rigidly connected to an end 211 of the crankshaft 210 on the side of the dispensing face DI, and a gear wheel 230 constrained to rotate with the end of a cam shaft 250, a drive chain or belt 212 surrounding said sprocket 200 and said gear wheel 230.

The jerky rotation causes vibroacoustic phenomena that have a negative impact on both the user comfort and the equipment affected by it, which may accelerate the ageing of the equipment or the changes in the performance or functional characteristics of the equipment.

It is known to make a dispensing arrangement. The dispensed setting may determine the relative position of the camshaft 250 with respect to the crankshaft 210. This setting will be characterized by the angle between the open or closed point of the valve, marked on the rotation plane of the crankshaft, and the low or high position of the crankpin of the crankshaft.

It is also known to set the angular position of the high-pressure fuel pump relative to the camshaft during the dispensing setting. This type of arrangement is not optimal and interferes with the operation of the engine.

To optimize the operation of the heat engine, depending on the type of high pressure pump, an oval sprocket 200 (such as the one shown in FIG. 2) with four lobes is mounted on the crankshaft in place of the conventional circular drive sprocket to reduce the effect of the high pressure pump's fourth harmonic on the delivery.

This oval sprocket 200 is used to reverse the H4 signal generated by the four lobes of the sprocket to the H4 jerky rotation of the high pressure pump to reduce the intensity of the jerky rotation.

The main difficulty with the use of an oval sprocket is the reduction of the setting deviation of the high pressure pump relative to an oval sprocket rigidly connected to the crankshaft. Indeed, if the H4 signal of the high pressure pump is no longer opposite in phase to the H4 signal generated by the oval sprocket, the situation may become worse and the jerky rotation may increase to a higher level than in the conventionally known case where a circular sprocket is used.

A good arrangement between the high-pressure pump 300 and the engine, in particular the crankshaft 210, is necessary to ensure that the forces generated by the pump do not disturb the engine, in particular during the start-up phase of the engine, the time of said phase becoming shorter and shorter. During other phases, interference may also be severe. The high-pressure pump 300 is therefore associated with the device 100 for positioning the fuel pump with respect to the crankshaft, which takes into account all the intermediate elements between the crankshaft 210 and the fuel pump 300, in particular the oval sprocket 200, the drive chain 212, the camshaft 250 and the high-pressure pump 300.

According to fig. 1, a high-pressure pump 300 according to one embodiment of the invention is arranged on one side of the engine and rotates towards the coupling surface AC of said engine. The coupling surface AC is the face opposite (along the longitudinal axis of the engine) to the accessory or dispensing surface DI from which extend one end of the crankshaft 211 and the first end 251 of the camshaft 250, to which the crankshaft transmits the rotary motion by means of a drive system comprising a drive sprocket 200 rigidly connected to the end of the crankshaft and a driven gear 230 rigidly connected to the first end 251 of the camshaft 250, wherein a drive belt or chain 212 surrounds the drive sprocket 200 and the driven gear 230, which belt or chain is designed to transmit the rotation of the crankshaft 210 to the camshaft 250.

The camshaft 250 is disposed in the cylinder head 50 of the engine, and the high-pressure fuel pump 300 is fastened to the wall 51 of the cylinder head 50.

The camshaft 250 has a gear 253 on a second end 252 that turns toward the coupling face of the engine opposite the first end 251, said gear meshing with an actuation sprocket 301 constrained to rotate with the actuation shaft 302 of the high-pressure fuel pump 300. As a result, rotation of crankshaft 210 drives rotation of camshaft 250, which in turn drives actuation of high-pressure fuel pump 300.

The axis of the camshaft 250 and the axis of the actuation shaft 302 of the high-pressure pump are parallel to the axis X of the crankshaft. They are denoted by the same reference numerals.

The setting device 10 of the high-pressure fuel pump 300 relative to the crankshaft 210 comprises means 11 for controlling the angular position of the crankshaft and further means 12 for controlling the angular position of the actuation shaft 302 of the fuel pump 300. The two means 11, 12 for controlling the angular position provide similar or identical accuracy.

According to the invention, the precision provided by the two means for controlling the angular position is the same and less than 1 ° or equal to 17 mrad.

Preferably, the two control devices are of the same type or the same. "same type" or "same" means that the two devices use similar sensors, making the same measurement of the angular position of comparable elements of the crankshaft on the one hand, and of the actuation shaft of the high-pressure pump on the other hand.

As shown in fig. 3 and 5, the control device for the crankshaft 210 includes:

a bore 214 traversing the engine's housing 215 in which the crankshaft 210 is housed. The axis of the bore is orthogonal to the longitudinal axis X of the crankshaft 210.

A flat face 216 machined on the element 217 of the crankshaft. In this embodiment, the flat face of the crankshaft is carried by a flange 217 fastened to the arm of said crankshaft 210, and is obtained by machining in this case the thickness of the flange. The flat face 216 is designed to be orthogonal to the axis of the through-hole 214. Accordingly, the crankshaft 210 is rotated so that the flat surface 216 comes into a position orthogonal to the axis of the through-hole 214.

A gauge 14 designed to be placed in the through hole 214 to be in contact with the flat face 216. Preferably, the gauge 14 is a leak gauge. Such gauges provide high control accuracy of the angular position of the crankshaft to about 0.3 °.

The flat surface 216 is formed such that the angular position of the crankshaft 210 when the measuring gauge is in contact with the flat surface is at its top dead center.

Preferably, the flange 217 may include a flat transverse notch (not shown) at the base of the planar face, forming an obtuse angle with the planar face 216. The notch enables the end of the gauge 14 opposite the flat surface 216 to be easily positioned.

As shown in fig. 3 to 5, the control device 12 of the high-pressure pump further includes:

a hole 52 crossing the wall 51 of the chamber in which the end 303 of the actuation shaft 302 of the pump 300 is housed, said end being rigidly connected to the actuation sprocket 301.

A flat face 310 on an element of the actuation sprocket 301. In the embodiment shown in fig. 3 and 5, the flat face 310 is obtained by machining a substantially parallelepiped-shaped element 304, which extends the teeth of the actuating sprocket 301 in the direction of the axis of the sprocket. The flat face 310 is designed to be orthogonal to the axis of the through-hole 52. Thus, rotating the actuation shaft 302 enables the flat face 310 to be brought into a position orthogonal to the axis of the through-hole 52.

A gauge 14 designed to be placed in the through hole 52 in contact with the flat face 310. Preferably, the gauge 52 is a leak gauge. Such gauges provide high control accuracy of the angular position of the crankshaft to about 0.3 °.

As shown in fig. 4, the parallelepiped-shaped element 304 is preferably radially carried by a tubular body which extends in line with the actuating sprocket in the direction of the axis of said sprocket. The tubular body has, at the base of the parallelepiped-shaped element 304, a transverse notch 305 forming an obtuse angle with the flat face of said element, so as to enable the end of the measuring gauge 15 opposite the flat face 310 to be easily positioned.

The high-pressure pump is mounted such that the angular position of the actuation shaft 302 of the high-pressure pump 300 is substantially aligned with the Top Dead Centre (TDC) of the camshaft 250 when the gauge 15 is in contact with the flat face 310 of the parallelepiped-shaped element 304. Top Dead Center (TDC) refers to the angular position of the camshaft or crankshaft that corresponds to the phase of opening of the exhaust valve and the piston (the piston corresponds to the exhaust valve reaching TDC in the cylinder of the engine), respectively. For this purpose, said mounting of the high-pressure pump 300 involves the following steps:

assembling the actuation sprocket 301 on the high-pressure pump 300,

assembling the gear 253 on the camshaft 250,

mounting of the high-pressure pump 300 by indexing of the actuation sprocket 301 of the high-pressure pump in the cylinder head 50,

the camshaft 250 is mounted in a given angular orientation with respect to the axis of rotation X of the camshaft.

The flat face 310 of the parallelepiped-shaped element 304 (and therefore of the actuation shaft 302) of the actuation sprocket 301 of the high-pressure pump is therefore adjusted with respect to the top dead centre of the camshaft 250.

The present invention proposes a new dispensing setting method involving setting a sprocket of a high-pressure pump by a Top Dead Center (TDC) of a crankshaft, which allows a setting deviation between the high-pressure pump and the crankshaft to be reduced compared to an existing deviation.

Contemplated setup mechanisms reverse the setup principle. Instead of setting the top dead center of the camshaft 250 relative to the top dead center of the crankshaft 210, thereby resulting in the position of the high-pressure pump relative to the crankshaft sprocket, it is proposed to set the actuation sprocket 301 of the high-pressure pump 300 relative to the top dead center of the crankshaft 210, thereby resulting in the position of the exhaust camshaft 250 relative to the crankshaft.

This provides for a higher accuracy when positioning the high pressure pump relative to the crankshaft and thus relative to the above mounted oval sprocket. It should be noted, however, that this may slightly reduce the positioning accuracy of the top dead center of the camshaft relative to the crankshaft, but this slight reduction is not critical to the operation of the engine.

Because the sprockets are keyed and clamped to the pump bosses, providing the pump sprockets is directly related to providing the high pressure pump.

The proposed new distribution setup mechanism therefore operates as follows:

1. the gauge 15 is brought into contact with the flat face 310 of the parallelepiped-shaped element 304 of the actuation sprocket 301 of the high-pressure pump to ensure the desired positioning of the high-pressure pump with respect to the top dead centre of the crankshaft. Thus, the camshaft 250 is substantially at top dead center due to the engagement between the camshaft and the pump via the actuation sprocket 301 and the gear 253 at the end of the camshaft.

2. The gauge 14 is brought into contact with the flat surface 216 of the crankshaft 210 at top dead center. The angular position of the crankshaft is accurately controlled using the control device 11 described above.

3. The dispensing and high pressure pump settings are locked in the established position by tightening the idler wheel's tightening screw.

The goal is achieved as: the apparatus and method for positioning a high pressure pump relative to a crankshaft achieves accurate end-to-end angular positioning.

Naturally, the invention is not limited solely to the embodiments described herein and described above by way of example, but encompasses all possible variations. The drive sprocket of the crankshaft may be a sprocket having a different shape.

Claims

1. An arrangement (10) for a high-pressure fuel pump (300) of a heat engine, the arrangement comprising:

-a crankshaft (210) housed in the casing of the engine and comprising an oval sprocket (200) rigidly connected to an end of the crankshaft turned towards a dispensing face (DI) of the engine,

-a camshaft (250) driven in rotation by the crankshaft using a transmission system around the oval sprocket,

-said high-pressure fuel pump comprises an actuation shaft (302) whose axis is parallel to the axis of the crankshaft and whose one end is driven in rotation by the end of the camshaft turned towards the coupling surface (AC) of the engine opposite to the dispensing surface (DI),

characterized in that the setting device (10) is capable of setting the fuel pump with respect to the crankshaft and comprises means (11) for controlling the angular position of the crankshaft and means (12) for controlling the position of the high-pressure fuel pump that provide equal precision, wherein the means (11, 12) for controlling the angular position of the crankshaft and the angular position of the high-pressure pump have a hole (214, 52) that crosses a housing surrounding the crankshaft and a housing surrounding the end of an actuation shaft (302) of the pump, respectively, the axis of the hole being orthogonal to the axis (X) of the shafts of the crankshaft and the pump.

2. The setting device (10) as claimed in claim 1, characterized in that the means (11) for controlling the angular position of the crankshaft and the means (12) for controlling the angular position of the high-pressure fuel pump are of the same type.

3. The setting device (10) as claimed in claim 1, characterized in that the bores (214, 52) are designed to receive measuring gauges (14, 15).

4. The setting device (10) as claimed in claim 3, characterised in that the measuring gauge (14, 15) is a leakage measuring gauge.

5. The setting device (10) as claimed in claim 1, characterized in that the crankshaft (210) and the high-pressure pump (300) have flat faces (216, 310) which are designed to be orthogonal to the axis of the bore (214, 52) of the housing which traverses the housing of the crankshaft and the housing of the end of the actuation shaft of the high-pressure fuel pump, respectively.

6. Setting device (10) according to claim 5, characterised in that the flat face (216) of the crankshaft is carried by a flange (217) rigidly connected to the arm of the crankshaft.

7. Setting device (10) according to claim 5, characterized in that the flat face (310) of the end of the actuation shaft (302) of the high-pressure fuel pump is carried by a tooth rigidly connected to an actuation sprocket (301) rigidly connected to the actuation shaft (302) of the high-pressure pump.

8. Method for setting the angular position of a high-pressure fuel pump of an engine by means of a heat engine, characterized in that it comprises the step of controlling the angular position of the high-pressure fuel pump by means of the crankshaft using a setting device according to any one of claims 1 to 7.

9. The method of claim 8, comprising the sequential steps of:

-bringing a gauge into contact with the crankshaft at top dead center,

-bringing the gauge into contact with the flat face of the parallelepiped-shaped element of the actuation sprocket of the high-pressure fuel pump.