WO2015197322A1

WO2015197322A1 - Method and system for managing the wear of an electro-hydraulic system of a motor vehicle

Info

Publication number: WO2015197322A1
Application number: PCT/EP2015/062286
Authority: WO
Inventors: Michael Schmitt; Linda CONSERVA
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2014-06-24
Filing date: 2015-06-02
Publication date: 2015-12-30
Anticipated expiration: 2016-12-24

Abstract

Method for managing the wear of an electro-hydraulic system (1) of an engine vehicle provided with an engine control unit (6), wherein sensors (11, 12) measure parameters which relate to the electro-hydraulic system (1) and which have an impact on the wear of said electro-hydraulic system (1), the engine control unit (6) processes the measured values of these parameters so as to identify events which have a negative impact on the wear of the electro-hydraulic system (1), the events are recorded in a memory (15) of the engine control unit (6) and, depending on all the events, the state of wear of the electro-hydraulic system (1) is evaluated and/or operation of the vehicle engine is controlled.

Description

DESCRIPTION Title

METHOD AND SYSTEM FOR MANAGING THE WEAR OF AN ELECTRO- HYDRAULIC SYSTEM OF A MOTOR VEHICLE

The present invention relates to a method for managing the wear of an electro- hydraulic system of a motor vehicle and to a corresponding management system. In particular, the present invention has an application, advantageously but not exclusively, in fuel injection systems, and in particular diesel fuel injection systems of the so-called common rail type, which comprise a high-pressure pumping unit, to which explicit reference will be made in the description without the latter thereby losing its general character.

The wear and the consequent breakage of a pumping unit of a common rail injec- tion system is increasingly more frequently the source of long and therefore costly disputes between suppliers of the pumping unit and clients during requests for repair made under the guarantee. The underlying causes of anomalous or excessive wear of the components of a high-pressure pumping unit, such as the pressure valves, intake valves and the gears of the high-pressure pump, are often dif- ficult to prove with certainty also for the manufacturer or supplier.

One of the possible causes of excessive wear or breakage of certain components of a pumping unit is the use of poor quality diesel fuel, i.e. fuel characterized by values of lubricity, viscosity, water content, dust and waste matter content which lie outside the standard values recommended by the manufacturer and/or supplier. The use of poor quality fuels accelerates ageing of the parts of the pumping unit especially if the latter is operated at maximum performance levels.

German patent application DE 10 2010 002017 Al describes a system for protecting against damage a diesel fuel pumping unit for a diesel cycle engine, said sys- tern comprising a plurality of sensors arranged in various parts of the diesel fuel tank for measuring properties of the diesel fuel which depend on ageing of the diesel fuel, an auxiliary tank for containing an additive and a control unit which ad- justs injection of additive into the diesel fuel tank depending on the last measurements so as to keep the quality of the diesel fuel at a sufficiently high level. However, this system does not take into account other factors which may have a negative impact on the wear of the fuel injection system, for example the atmosphere in which the engine operates or other malfunctions not associated with the quality of the diesel fuel.

The object of the present invention is to provide a system which is able to manage in the best possible manner the wear of a diesel fuel injection system, overcoming the drawbacks described above while being easy and inexpensive to produce.

In accordance with the present invention a method and a system for managing the wear of an electro-hydraulic system of a motor vehicle are provided, in accordance with that defined in the accompanying claims. The present invention will now be described with reference to the sole attached figure which illustrates a non-limiting example of embodiment thereof.

In the figure, 1 denotes generally, as a whole, an electro-hydraulic system consisting of a fuel injection system which draws fuel, in particular diesel fuel, from a tank 2 and feeds it to an internal combustion engine (not shown), in the case in question a Diesel cycle combustion engine for a medium-weight or heavy commercial vehicle of the on-road or off-road type. The fuel injection system 1 comprises a fuel distribution manifold, indicated by 3 in the figure and commonly referred to as "common rail", a plurality of injectors 4 connected to the manifold 3 for atomizing the fuel inside corresponding combustion chambers of the engine, and a high- pressure pumping unit 5 for pumping the fuel under pressure into the manifold 3. The fuel injection system 1 is controlled by an engine control unit 6 associated with the engine. The pumping unit 5 comprises a high-pressure pump 7, in the case in question a piston pump, and a hydraulic circuit 8 for conveying the fuel from the tank 2 to the manifold 3. The hydraulic circuit 8 comprises a first branch 9 for connecting the tank 2 to the pumping unit 5 and a second branch 10 for connecting the pumping unit 5 to the manifold 3.

According to the present invention the vehicle is equipped with a temperature sensor 11 mounted in the pumping unit 5, for example at the outlet of the pump 7, for measuring the temperature of the diesel fuel output by the pumping unit 5 and in particular at the outlet of the pump 7, and a sensor device 12 arranged along the branch 9, and in particular along an output duct 13 of the tank 2, and comprising one or more sensor elements for measuring one or more parameters indicat- ing the quality of the fuel. The parameters indicating the quality of the fuel comprise one or more parameters from among the following: lubricity of the diesel fuel, viscosity of the diesel fuel, water content of the diesel fuel, and dust and/or waste matter content of the diesel fuel. The engine control unit 6 comprises an associated processing unit 14 and a memory 15, for example an EEPROM. According to the present invention, the processing unit 14 is configured to process the measured temperature values provided by the sensor 11 and the measured values of the parameters indicating the quality of the diesel fuel measured by the sensors 12 so as to identify events which potentially may accelerate ageing of the fuel injection system 1. The events identified are immediately recorded in the memory 15 for subsequent uses which have the object of managing in the best possible manner the wear of the components of the fuel injection system 1, as will be explained more fully below in the present document. In fact, the events recorded contain information about any anomalies which have occurred during the entire working cycle of the fuel injection system 1.

In greater detail, standard value ranges are stored in the memory 15, these being referred to below more succinctly as "standard ranges", relating to the operating temperature of the diesel fuel and the parameters indicating the quality of the diesel fuel. The standard ranges are normally defined by the manufacturer and therefore constitute those ranges of values which, if complied with, ensure, according to the manufacturer, a certain working life for the fuel injection system 1. Preferably, the standard ranges are stored prior to initial use of the fuel injection system 1.

The processing unit 14 determines the events to be recorded by means of a comparison between the values measured and the corresponding standard ranges. For example, if the measured values lie outside of the standard ranges, then these measured values are stored in the memory 15 each together with a respective "time stamp" which encodes the date and time of the recording. Moreover, the measured values are also stored as soon as they fall back within the standard ranges, together with the respective time stamps. In other words, each event is a set of data which comprises a measured value which has fallen outside the corresponding standard range or which falls back within the corresponding standard range and a respective time stamp.

Advantageously, the following are also stored in the memory 15: the identification codes, namely the serial numbers, of at least some of the components of the fuel injection system 1 together with respective time stamps which encode the data and time of installation or replacement of the corresponding components. In other words, the identification codes are stored only once for each component, at the moment of installation or replacement thereof. These components comprise, for example, the pump 7, any electric pre-feed pump for feeding the pump 7, the injectors 4, a water separator device and the fuel filters. Advantageously, the parameters monitored also comprise the number of starl stop cycles of the engine, which is measured, for example, by means of a counter installed in the engine control unit 6, or by means of an external measuring device (not shown) communicating with the engine control unit 6, and is compared, by the processing unit 14 with a maximum number of starl stop cycles predefined by the manufacturer and stored in the memory 15. In this case the standard range lies between zero and the maximum number of starl stop cycles and the object of the comparison is to detect the event where this maximum number of starl/stop cycles is exceeded. According to a first aspect of the invention, the identification codes of the components and the events recorded in the memory 15 of the engine control memory 6 may be read by the common diagnostics instruments 16 of the motor vehicle workshops, transferred into a special centralized databank 17 and used at a later time for post-evaluation of the state of wear of the fuel injection system 1 and in particular for determining the causes of the wear of the components of the fuel injection system 1 in order to establish whether a request for repair under a guarantee may be accepted. For this purpose, the diagnostics instruments 16 are equipped with software 18 which evaluates the request for repair under guarantee in the light of the conditions agreed between supplier of the components and manufacturer of the original components (OEM) and depending on the identification codes and all the events stored in the databank 17. A situation where this method is applied consists, for example, of a request for repair under guarantee of the pump 7 which is typically designed for use all over the world, i.e. so as to be compatible with a large variety of types of diesel fuel. The use - even only occasionally - of diesel fuel which is old or contaminated with waste matter may result in breakage of the pump 7 and, consequently, complete breakage of the fuel injection system 1. The events recorded during the entire working cycle of the fuel injection system 1 show the periods in which the poor quality diesel fuel was used, even if the tank was last refilled with high-quality fuel, and therefore allows one to identify the real cause of breakage of the fuel injection system 1.

According to a further aspect of the invention, the engine control unit 6 controls the engine depending on the all the events recorded. In particular, the processing unit 14 adjusts some of the control parameters of the engine depending on the events recorded so as to optimize the balance between performance and duration of the working cycle of the fuel injection system 1. The aforementioned engine control parameters comprise, for example, one or more of the following parameters; the maximum permitted speed of rotation of the engine, the maximum permitted pressure inside the duct 3, the maximum permitted volume of the fuel.

Advantageously, adjustment of the engine control parameters is also performed depending on the last measured values of the aforementioned monitored parameters. In this way it is possible to adjust optimization in a manner which is most appropriate to the current situation. For example, in the case where the vehicle is travelling in a country where the quality of the diesel fuel is normally inferior to that which can be found in western Europe (EN590), the engine control parameters may be set to values lower than the limit values for the engine so that the balance between performance and duration is shifted so as to favour more the duration. However, in this country it may also be possible to find a fuel pump which supplies high-quality diesel fuel and therefore the engine control parameters may be set to limit values for the engine such as to increase the performance, namely shift the balance between performance and duration so as to favour more the performance. Advantageously, programmed maintenance data relating to the fuel injection system 1 is stored in the memory 15 and adjustment of the engine control parameters is also performed depending on the programmed maintenance data and in par- ticular depending on the next planned maintenance.

Therefore, the sensors 11 and 12 and the engine control unit 6 form a management system which allows the best possible management of the wear of the fuel injection system 1, so that, on the one hand, data useful for establishing the real cause of any breakage of a component of the fuel injection system 1 may be recorded and so that, on the other hand, operation of the combustion engine may be controlled in real time so as to optimize the balance between performance and duration of the working life of the fuel injection system 1.

Although the invention described above makes particular reference to a well- defined example of embodiment, it is not to be regarded as being limited to this example of embodiment, its scope including all those variants, modifications or simplifications which would be obvious to the person skilled in the art, such as: - the application to petrol injection systems;

- the application to another electro-hydraulic system of the motor vehicle, such as the braking system of the vehicle, where the measured parameters comprise the fluid circulating in the circuit of the braking system.

Claims

Method for managing the wear of an electro-hydraulic system of a motor vehicle provided with an engine control unit, the method comprising:

measuring, by means of sensor means (11, 12), first parameters which relate to the electro -hydraulic system (1) and have an impact on the wear of said electro-hydraulic system (1);

processing, by the engine control unit (6), of the measured values of the said first parameters so as to identify events which have a negative impact on the wear of the electro-hydraulic system (1);

recording said events in a memory (15) of the engine control unit (6); and evaluating the state of wear of the electro-hydraulic system (1) and/or controlling operation of the engine of the vehicle depending on the events recorded.

Method according to Claim 1 and comprising:

storing, in said memory (15), standard value ranges relating to said first parameters;

said events being identified by means of a comparison between the measured values and the corresponding standard value ranges.

Method according to Claim 2, wherein said recorded events comprise those measured values which fall outside of the corresponding standard value ranges or which have just fallen back within these standard value ranges and respective time stamps which encode the date and time of the recording.

Method according to one of Claims 1 to 3, wherein said vehicle is propelled by an internal combustion engine and said electro-hydraulic system is formed by a fuel injection system (1) for feeding the fuel to the internal combustion engine; said first parameters comprising the temperature of the fuel fed to the internal combustion engine.

Method according to Claim 4, wherein said fuel injection system (1) is a system for high pressure injection of diesel fuel, which comprises a high- pressure pumping unit (5); said temperature being the temperature of the diesel fuel measured at the outlet of the high-pressure pumping unit (5).

Method according to Claim 4 or 5, wherein said first parameters comprise at least one second parameter indicating the quality of the fuel.

Method according to Claim 6, wherein said fuel injection system (1) comprises a hydraulic circuit (8) for drawing the fuel from an associated tank (2); said at least one second parameter being measured along a branch (9) of the hydraulic circuit (8) connected to the tank (2).

Method according to Claim 6 or 7, wherein said fuel injection system (1) is a system for high-pressure injection of diesel fuel; said at least one second parameter comprising one or more parameters selected from a group consisting of: lubricity of the diesel fuel, viscosity of the diesel fuel, water content of the diesel fuel, and dust and/or waste matter content of the diesel fuel.

Method according to one of Claims 1 to 8, wherein said vehicle is propelled by an internal combustion engine and said first parameters comprise the number of starl stop cycles of the engine.

Method according to one of Claims 1 to 9, wherein evaluation of the state of wear of the electro-hydraulic system (1) is carried out by reading from said memory (15) and taking into account said recorded events by means of diagnostic means (16) outside said engine control unit (6).

Method according to Claim 10, wherein said electro-hydraulic system (1) comprises a plurality of components which have respective identification codes; the method comprising:

storing, in said memory (15), the code for identifying each component at the time of installation or replacement of the component;

evaluation of the state of wear of the electro -hydraulic system (1) being performed by reading from said memory (15) and taking into account said iden- tification codes by means of said diagnostic means (16).

12. Method according to Claim 1 to 11, wherein controlling operation of the vehicle engine comprises:

- adjusting, by means of said engine control unit (6), engine control parameters depending on said recorded events so as to optimize the balance between performance and duration of the working life of the electro-hydraulic system (1).

13. Method according to Claim 12, wherein said adjustment of the engine control parameters is performed depending on the last of said measured values.

14. Method according to Claim 12 or 13 and comprising:

storing, in said memory (15), programmed maintenance data relating to said el ectro - hy d rau I ic system (1) ;

said adjustment of the engine control parameters being performed depending on said programmed maintenance data.

15. System for managing the wear of an electro-hydraulic system (1) of a motor vehicle, the management system comprising sensor means (11, 12) for measuring values of first parameters which relate to the electro-hydraulic system (1) and which have an impact on the wear of the said electro- hydraulic system (1), and an engine control unit (6) which comprises a memory (15) and is configured to implement the method according to one of Claims 1 to 14.

Management system according to Claim 15, wherein said vehicle is propelled by an internal combustion engine and said electro-hydraulic system is formed by a fuel injection system (1) which comprises a hydraulic circuit (8) for drawing the fuel from a tank (2) and feeding the fuel to the engine; said sensor means (11, 12) comprising at least one fuel quality sensor (12) for measuring a parameter indicating the quality of the fuel in a branch (9) of the hydraulic circuit (8) connected to the tank (2).

Management system according to Claim 15 or 16, wherein said vehicle is propelled by an internal combustion engine and said electro-hydraulic system is formed by a fuel injection system (1) for feeding the fuel to the en- gine; said sensor means (11, 12) comprising a temperature sensor (11) for measuring the temperature of the fuel fed to the engine.