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(11) | EP 1 961 954 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | A multipurpose diagnostics apparatus for a direct-injection petrol or diesel engine preferably with common-rail technology |
| (57) The present invention regards a multipurpose diagnostics apparatus (1) for an engine,
said apparatus comprising: a central unit (2) provided with processing and control
means (8) and interface means (3, 4) for interaction between the user and said processing
and control means (8); and connection means (5, 5', 5"), via which said central unit
(2) can be connected to one or more components of said engine according to different
configurations; said processing and control means (8) enabling the operator to carry
out tests on operation of one or more components of the high-pressure electro-hydraulic
part, activating autonomously the components being tested and measuring the operating
parameters, and subsequently correlating the values obtained from said tests and from
said measurements with one or more criteria that can be pre-set and selected using
said interface means (3, 4) by said user so as to detect proper operation of each
of said components individually.
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[0001] The present invention relates to a multipurpose diagnostics apparatus for a direct-injection petrol or diesel engine that preferably uses common-rail technology.
[0002] In greater detail, the invention regards an apparatus that enables verification of operation of the parts of the injection system of an engine, overcoming the limits of common self-diagnostics systems that are installed on automobiles or that may be applied thereto.
[0003] As is well known, currently new technologies have radically modified operation and control of engines. Already today the evolution of technology requires the car mechanic to be able to sustain high levels of investments, through which the workshop can increase its own market share and remain competitive, also in view of the fact that the car mechanic must not only be able to provide replacement of damaged parts but must also be able to offer the advantageous alternative of carrying out repairs.
[0004] There are by now present on the market, for example, new diesel engines, equipped with high-pressure systems, said engines being also known as common-rail diesel engines. These have made it possible to achieve high levels of performance together with low pollutant emissions.
[0005] On the basis of what has been outlined above, in order to remain competitive, modern workshops must be provided with suitable equipment.
[0006] The fuel-supply system of common-rail engines is one of the most delicate aspects and hence one that most frequently must undergo repair.
[0007] The fuel-supply system of a common-rail engine can be divided into:
- low-pressure system; and
- high-pressure system.
[0008] The fuel-supply system is controlled by the engine electronic control unit by means of a cross-check of the fuel-pressure sensor and the duty cycle of the high-pressure regulator. Consequently, whenever a problem arises in the fuel-supply system, said engine electronic control unit detects an error in the pressure regulation of the fuel, without specifying which component presents the failure. For instance, the engine electronic control unit is unable to distinguish between the following faults:
- injector with high return;
- injector blocked;
- inefficient pressure connection;
- inefficient high-pressure pump;
- low-pressure pump out of order;
- fuel filter clogged;
- high-pressure regulator blocked;
- flow regulator blocked;
- irregular idling.
[0009] In addition, if we consider the case where the engine fails to start, the self-diagnostics system of the engine is unable to check the efficiency of the hydraulic system and even to check control of high pressure.
[0010] Hence in all the cases listed above, the engine electronic control unit, irrespective of the faults present, would always detect the same error of regulation of the fuel pressure. As a result, the car mechanic will be faced with the problem of trying to understand which element of the system needs to be replaced, since the self-diagnostics system is unable to carry out either activation of the pressure regulator and of the flow regulator or control of the injector.
[0011] A proper diagnosis would entail the use of different types of equipment and/or additional personnel, and this would in turn entail high costs in terms of money.
[0012] In particular, for example, in order to carry out a check on the efficiency of the high-pressure pump, it would be necessary to take the pump down.
[0013] In such a framework, the purpose of the present invention is to propose a diagnostics device that is simple to use and that will enable clear identification of the various faults present in the fuel-supply system directly on the vehicle being tested, and in particular, for instance:
- (a) the efficiency of the high-pressure pump;
- (b) the fluid tightness of the injectors;
- (c) the efficiency of the pressure regulator;
- (d) the efficiency of the flow regulator; and
- (e) proper operation of the fuel-pressure sensor.
[0014] Consequently, forming a specific subject of the present invention is a multipurpose diagnostics apparatus for an engine, said apparatus comprising: a central unit provided with processing and control means and interface means for interaction between the user and said processing and control means; and connection means, via which said central unit can be connected to one or more components of said engine according to different configurations; said processing and control means enabling the operator to carry out tests on operation of one or more components of the high-pressure electro-hydraulic part, activating autonomously the components being tested and measuring the operating parameters, and subsequently correlating the values obtained from said tests and from said measurements with one or more criteria that can be pre-set and selected using said interface means by said user so as to detect proper operation of each of said components individually.
[0016] Yet again according to the invention, said at least one electrical cable can connect said central unit to the supply battery of the vehicle undergoing troubleshooting.
[0017] Furthermore according to the invention, said processing and control means may be programmable in order to enable said tests on operation to be carried out on said one or more components and applying said one or more pre-settable criteria.
[0018] Advantageously, according to the invention, said processing and control means comprise a microcontroller, an analog-to-digital converter, a generator of square-wave pulses with variable duty cycle, and a power unit.
[0019] Once again according to the invention, said interface means can comprise a liquid-crystal display.
[0023] Preferably, according to the invention, said components of said engine can comprise the pressure sensor.
[0024] Once more according to the invention, said components of said engine can comprise a pressure regulator.
[0025] Furthermore according to the invention, said components of said engine can comprise at least one coil injector or piezoelectric injector.
[0026] Advantageously, according to the invention, said engine can be a direct-injection petrol or diesel engine preferably with common-rail technology.
[0027] The present invention will be now described, purely by way of illustrative and non-limiting example, according to its preferred embodiments, with particular reference to the figures of the attached plates of drawings, in which:
- Figure 1 shows a block diagram of a multipurpose diagnostics apparatus for an engine according to the present invention;
- Figure 2 shows an electrical block diagram of the central unit of the multipurpose diagnostics apparatus according to Figure 1;
- Figure 3 shows a first configuration of connection of the apparatus according to the invention;
- Figure 3a shows a block diagram of operation of the apparatus according to the invention in the configuration of connection according to Figure 3;
- Figure 4 shows a second configuration of connection of the apparatus according to the invention;
- Figure 4a shows a block diagram of the operation of the apparatus according to the invention in the configuration of connection according to Figure 4;
- Figure 5 shows a third configuration of connection of the apparatus according to the invention;
- Figure 5a shows a block diagram of operation of the apparatus according to the invention in the configuration of connection according to Figure 5;
- Figure 6 shows a fourth configuration of connection of the apparatus according to the invention; and
- Figure 7 shows the logic of operation of the apparatus according to the invention.
[0028] As a preliminary, it is deemed expedient to provide some notions regarding the parts of the fuel-supply system of an engine.
[0029] As has been said, a fuel-supply system of a common-rail engine can be divided into a low-pressure system and a high-pressure system.
[0030] The former consists of a low-pressure pump, the function of which is to draw in the fuel from the tank and send it to the high-pressure pump. The pressure of said pump is generally 2.5-3 bar.
[0031] The high-pressure system, instead, consists of a so-called high-pressure pump, the function of which is to pressurize the fuel inside the common rail, which is designed to accumulate the fuel at a high pressure.
[0032] Regulation of the pressure at output is entrusted to a pressure regulator, which in general is set either on the rear part of the high-pressure pump or at the end of the common rail, or else to a flow regulator (some versions may be simultaneously equipped both with the pressure regulator and with the flow regulator). Said regulators are controlled by the engine electronic control unit, by means of a feedback connection with the pressure sensor fixed on said common rail.
[0033] Said fuel-pressure sensor has the function of detecting the pressure present in the common rail and sending to said engine electronic control unit a signal proportional to said pressure. Said sensor envisages a socket with three connection wires: ground, 0.5-4.5-V signal, and 5-V supply.
[0034] The fuel accumulated in the common rail is sent, during operation of the engine, to the injectors by means of pipes, preferably made of metal.
[0035] The injector has the function of injecting the fuel into the engine cylinder and is controlled by the engine electronic control unit, by means of an electric control. The interval of duration of said control varies, in any case, according to the type or version of engine.
[0036] With reference now to Figures 1 and 2, there may be noted the multipurpose diagnostics apparatus 1 for an engine, of the type described above.
[0037] Said apparatus 1 comprises a central unit 2, provided with a liquid-crystal display 3, and a pushbutton panel 4 having five pushbuttons (Enter, Start-Stop, Esc, Arrow-up and Arrow-down).
[0038] The apparatus 1 moreover comprises connection means 5, which enable connection of said apparatus to the system for supply of one or more parts of the engine in order to carry out the necessary diagnostics.
[0039] As may be noted, in the central unit 2 the display 3 is connected via an electrical flat conductor cable 6 to an electronic card 7, on which the pushbutton panel 4 is installed.
[0040] Also installed on said electronic card 7 is a programmable processing and control microcontroller 8 and the biasing passive circuit components.
[0041] The connection means comprise the electrical cables 5', for connection to supply means, such as the battery of the engine of the motor vehicle on which the diagnostics is carried out, and the electrical cables 5'' for connection to the various components of said engine.
[0042] Once said apparatus 1 has been connected to the components of the engine according to different configurations, it enables, by means of said microcontroller 8:
- electronic activation of some components of the engine (regulators, injectors, various actuators) by means of appropriate electrical signals;
- carrying out of tests on operation of said components of the engine;
- carrying out of measurements of operating parameters of said components of the engine;
- carrying out of calculations of correlation between the values obtained from the tests on operation and the values of the aforesaid operating parameters, according to criteria that can be pre-set by programming said microcontroller 8 and that can be selected by a user using said pushbuttons 4 and the display 3.
[0043] Illustrated hereinafter are some possible configurations of connection of the apparatus 1 according to the invention, where there are distinguished a first part concerning checks on the vehicle and a second part regarding carrying out of the bench tests.
Part I - checks on the motor vehicle (components mounted on the engine)
[0044] Figures 3 and 3a show the configuration for checking efficiency of the pressure-regulator valve. The following steps are performed with the control board of the vehicle 9 on which troubleshooting is being carried out turned off:
- connect the central unit 2 by means of a pair of clamps to the battery of the vehicle being tested;
- disconnect the wiring of the pressure regulator 11;
- insert a standard regulator (provided along with the apparatus) on the vehicle, in order to inhibit the function of error-detection (recovery function) of the vehicle 9 during the test with the engine running;
- connect the wiring suitable for the central unit 2 to the pressure regulator 11;
- connect the central unit 2 to the fuel-pressure sensor 10 (0.5 V with the control board turned on);
- select engine-starting test;
- start the engine and press the Start pushbutton 4.
[0045] With the engine running:
- control the pressure displayed (for example, approximately 300/400 bar on diesel engines);
- press the key Arrow-up and check for an increase in pressure;
- press the key Arrow-down and check for a decrease in the pressure;
- in order to turn off the engine, set the control control board on Stop and press Stop on the central unit 2.
[0046] In particular, the signal detected by the pressure sensor 10, once filtered by a filter 8', is processed by said microcontroller 8, which carries out an analog-to-digital conversion thereof.
[0047] Using the above configuration, it is possible, by controlling the pressure regulator 11 of the common-rail fuel-supply system, to obtain internal cleaning of the system with the aid of chemical products.
[0048] Furthermore, with the above configuration it is possible to check the efficiency of the high-pressure pump and the fluid tightness of the injectors. In this case, before carrying out the test, proper operation of the low-pressure system at 2.5 bar must be ensured. With the control board turned off, the following operations are performed:
- connect the central unit 2 by means of a pair of clamps to the battery of the vehicle being tested;
- disconnect the wiring of the pressure regulator 11;
- insert a standard regulator (provided along with the apparatus) on the vehicle in order to inhibit the function of error detection (recovery function) of the automobile 9 during the test with the engine running;
- disconnect the phase sensor or the injector sockets (not shown in the figure);
- connect the central unit 2 via the electrical cable 5" to the pressure regulator 11;
- connect the central unit 2 to the wire of the pressure sensor 10 (0.5 V with control board turned on);
- connect the central unit 2 to the battery supply of the automobile 9;
- select test for fluid tightness;
- start the engine and press the Start pushbutton 4;
- check the pressure displayed in the engine-starting phase (for example, 600/800 bar in diesel engines);
- if said pressure has not been reached check fluid tightness of the injectors, and, if the injectors are functioning properly, intervene on the high-pressure pump.
[0049] In addition, in the above configuration, if when the key Arrow-up is pressed there is an increase in pressure and when the key Arrow-down is pressed there is a decrease in pressure, it is possible to make a check on control of the efficiency of the pressure-regulation valve.
[0050] Figures 4 and 4a show the configuration for checking efficiency of the flow-regulation valve. The following steps are performed with the control board of the vehicle 9 on which troubleshooting is being carried out turned off:
- connect the central unit 2 by means of a pair of clamps to the battery of the vehicle being tested;
- disconnect the wiring of the flow regulator 12;
- inserting a standard regulator (provided along with the apparatus) on the vehicle in order to inhibit the error-detection function (recovery function) of the vehicle 9 during the test with engine running.
- connect the wiring suitable for the apparatus 1 to the regulator;
- connect the central unit 2 to the fuel-pressure sensor 10 (0.5 V with control board turned on);
- select the engine-starting test;
- start the engine and press the Start pushbutton 4.
[0051] With the engine running:
- control the pressure displayed (for example, 300/400 bar in diesel engines);
- press the key Arrow-up and check for an increase in pressure;
- press the key Arrow-down and check for a decrease in pressure;
- in order to turn off the engine, set the control board on Stop and press Stop on the central unit 2.
[0052] It may be clearly noted in Figure 4a that the connection of the apparatus 1 can be performed simultaneously both with the flow regulator and with the pressure sensor 10. Once the microcontroller 8 has detected the signals measured by the pressure sensor 10 of the engine 9' of the automobile 9, it regulates the duty cycle under the control of a square-wave pulse generator 15 (the control modulation is of a PWM - Pulse Width Modulation - type). The square wave is appropriately modulated to obtain control of the pressure regulator 11 and is amplified with a power unit 14, with which the apparatus 1 is equipped.
[0053] With this configuration, it is possible, by controlling the flow regulator 12 of the common-rail fuel-supply system, to perform internal flushing of the system with the aid of chemical products.
[0054] Furthermore, with said configuration, it is possible to check the efficiency of the high-pressure pump and the fluid tightness of the injectors. In this case, before conducting the test, proper operation of the low-pressure system at 2.5 bar must be ensured. With the control board turned off, the following operations are performed:
- connect the central unit 2 by means of a pair of clamps to the battery of the vehicle being tested;
- disconnect the wiring of the flow regulator;
- insert a standard regulator (provided along with the apparatus) on the vehicle in order to inhibit the error-detection function (recovery function) of the vehicle 9 during the test with the engine running;
- disconnect the phase sensor or injector sockets (not shown in the figure);
- connect the central unit 2 by means of the electrical cable 5" to the flow regulator;
- connect the central unit 2 to the wire of the pressure sensor 10 (0.5 V with control board turned on);
- connect the central unit 2 to the battery supply of the vehicle 9;
- select the fluid-tightness test;
- start the engine and press the Start pushbutton 4;
- check the pressure displayed in the starting step (for example 600/800 bar in diesel engines);
- if said pressure is not reached, check the fluid tightness of the injectors, and, if the injectors are functioning properly, intervene on the high-pressure pump.
[0055] In addition, in the above configuration, if when the key Arrow-up is pressed there is an increase in pressure and when the key Arrow-down is pressed there is a decrease in pressure, it is possible to check control of the efficiency of the flow-regulation valve.
[0056] Figures 5 and 5a show the configuration for checking operation of the fuel-pressure sensor 10 (high-pressure pressure gauge). In this configuration, with the control board turned off, the following operations are performed:
- disconnect the wiring of the fuel-pressure sensor 10;
- connect an electrical cable 5'' to the wire of the signal (0.5 V, pressure sensor);
- connect the supply of the central unit 2 to the battery of the vehicle;
- select the pressure gauge by means of the pushbutton panel 4;
- switch on the control board and check that the pressure displayed is 25-30 bar (for systems with electrical pump);
- run the engine and check that the pressure rises (for example, approximately 350 bar in diesel engines);
- during acceleration, check that the value displayed does not present jumps as it increases.
[0057] From Figure 5a it emerges that the square-wave pulse generator 15, controlled by said microcontroller 8, generates a square wave having a suitable duty cycle, amplified by the power unit 14, for driving the injector 11.
[0058] Figure 6 shows a configuration of connection in which said one central unit 2 is connected to an injector 13, for checking operation of the electronic part of the aforesaid injector.
[0059] In particular, with the control board turned off, the following operations are performed:
- disconnect the wiring of the injector 13 to be checked;
- connect the wiring 5" suitable for the injector;
- select the make of the injector 13;
- set the injector opening time;
- press the Start pushbutton 4;
- hear a characteristic noise coming from the solenoid;
- using the keys Arrow-up and Arrow-down, vary the frequency of opening.
Part II - (bench tests)
[0060] Finally, it is also possible to carry out bench tests by means of the central unit 2, and in particular it is possible to carry out a check on operation of an injector (in this case, the aid of a manual pump and of a fume aspirator is necessary). Said check is carried out as follows:
- connect the injector 13 to the manual pump by means of a high-pressure pipe;
- switch the aspirator on;
- connect the wiring 5" suitable for the injector 11;
- select the type of injector 13;
- set the injection time;
- bring the pressure of the system up to approximately 300 bar;
- press the Start pushbutton 4;
- check nebulization of the product by the pulverizer;
- check that there is not an excessive return from the injector;
- in the case of lack of pulverization or excessive injector return, get the injector 13 overhauled.
[0061] The check on operation of an injector 13 can be carried out also on a piezoelectric injector.
[0062] Figure 7 shows the tree of the possible functions of the apparatus 1 according to the present invention. In particular, it may be noted how at a first level, the apparatus 1 enables selection of the type of test to carry out, such as tests on injectors, high-pressure gauge, and high-pressure pump.
[0063] The apparatus 1 also enables calibration of the test according to the make or type of component of the engine. In the case in point, the apparatus 1 is suitable for carryng out tests on Bosch® and Delphi® components.
[0064] At a further level, it is possible to select the effective test to be carried out on the component (engine starting, fluid tightness, flushing of the common rail), in such a way that then the central unit 2 and in particular the processing and control means 8 will be able to set the correct signal for carrying out the test on operation.
[0065] On the basis of the foregoing description, it may be noted that the main advantage of the present invention is the possibility of carrying out tests on operation of the components of the high-pressure electro-hydraulic part without necessarily having to detach said components from the vehicle being tested, but, by controlling them directly, being able to analyse the reaction of the system in question, carry out measurements on operating parameters of an engine, and allow detection of proper operation of the components of an engine.
[0066] An advantage of the present invention is that of enabling management and control of: pumps and injectors that use common-rail technology (both diesel and petrol engines); fuel-pressure sensors; duty cycle in the control of the pressure regulator during the tests of engine starting/fluid tightness and control of the flow regulator during the tests of engine starting/fluid tightness; control of the high-pressure system by means of the appropriate wiring.
[0067] The present invention has been described purely by way of illustrative, but non-limiting, example according to its preferred embodiments, but it is to be understood that variations and/or modifications may be made by persons skilled in the branch, without this implying any departure from the corresponding sphere of protection, as defined by the annexed claims.
1. A multipurpose diagnostics apparatus (1) for an engine, said apparatus comprising:
a central unit (2) provided with processing and control means (8) and interface means
(3, 4) for interaction between the user and said processing and control means (8);
and connection means (5, 5', 5''), via which said central unit (2) can be connected
to one or more components of said engine according to different configurations; said
processing and control means (8) enabling the operator to carry out tests on operation
of one or more components of the high-pressure electro-hydraulic part, activating
autonomously the components being tested and measuring the operating parameters, and
subsequently correlating the values obtained from said tests and from said measurements
with one or more criteria that can be pre-set and selected using said interface means
(3, 4) by said user so as to detect proper operation of each of said components individually.
2. The apparatus (1) according to Claim 1, characterized in that said connection means comprise electrical cables (5, 5', 5'').
3. The apparatus (1) according to Claim 1, characterized in that at least one electrical cable connects said central unit (2) to the supply battery
of the vehicle (9) undergoing troubleshooting.
4. The apparatus (1) according to any one of the preceding claims, characterized in that said processing and control means (8) are programmable for conducting said tests
on operation of said one or more components and said one or more pre-settable criteria.
5. The apparatus (1) according to any one of the preceding claims, characterized in that said processing and control means comprise a microcontroller (8).
6. The apparatus (1) according to any one of the preceding claims, characterized in that said processing and control means comprise an analog-to-digital converter (8').
7. The apparatus (1) according to any one of the preceding claims, characterized in that said processing and control means comprise a generator of square-wave pulses (15)
with duty cycle.
8. The apparatus (1) according to any one of the preceding claims, characterized in that said processing and control means comprise a power unit (14).
9. The apparatus (1) according to any one of the preceding claims, characterized in that said interface means comprise a liquid-crystal display (3).
10. The apparatus (1) according to any one of the preceding claims, characterized in that said interface means comprise a pushbutton panel (4).
11. The apparatus (1) according to Claim 10, characterized in that said pushbutton panel (4) comprises five pushbuttons.
12. The apparatus (1) according to any one of the preceding claims, characterized in that said parameters comprise the pressure of the fuel.
13. The apparatus (1) according to any one of the preceding claims, characterized in that said components of said engine comprise the pressure sensor (10).
14. The apparatus (1) according to any one of the preceding claims, characterized in that said components of said engine comprise a pressure regulator (11).
15. The apparatus (1) according to any one of the preceding claims, characterized in that said components of said engine comprise a flow regulator (12).
16. The apparatus (1) according to any one of the preceding claims, characterized in that said components of said engine comprise at least one coil injector or piezoelectric
injector.
17. The apparatus (1) according to any one of the preceding claims, characterized in that said engine is a direct-injection petrol or diesel engine preferably with common-rail
technology.