MXPA00002007A - Fuel injection diagnostic control device - Google Patents

Abstract

A diagnostic/control device for fuel injected internal combustion engines comprising a control system (14) connectable via leads (16) to the fuel injectors (10) after disconnection therefrom of an engine management computer (11), the latter being connected directly (at 18) to the control system (14). An oxygen sensor (13) is connected (at 17) to the control system (14) whereby the latteris connected between the engine management computer (11) and the fuel injectors (10) and can be operated in closed circuit or open circuit mode to control the injectors directly when required independently of the engine management computer (11).

Description

FUEL INJECTION DIAGNOSTIC CONTROL DEVICE DESCRIPTION OF THE INVENTION This invention relates to an auxiliary or automotive diagnostic control device for electronic fuel-injected fuel-driven (EFI) engines. Most modern gas-powered production cars are equipped with catalytic converters and an engine management system, which electronically controls the air / fuel ratio (AFR), incorporating the use of an oxygen sensor and operating in what is known as a "closed loop" mode. Oxygen readings are transmitted to an engine management computer (ECU) along with several other parameters, and adjustments are made electronically to provide repeated self-correction of the AFR. This is intended to make the engine operate at perfect combustion with an AFR of 14.75.1 (also known as Factor 1). However, this closed loop operation mode can make many faults difficult to diagnose. For example, a vehicle with an air leak from the intake manifold could idle very irregularly as the ECU attempts to compensate by adjusting the amount of fuel fed to the engine, based on incorrect readings taken from an air flow meter, which is located before the point of air leakage. This makes traditional diagnostic methods difficult, since, in most cases, it is necessary to make the motor stable before starting common test procedures. 5 One aspect of achieving a stabilized operation before curing a fault such as this is to take the vehicle out of the closed loop mode and force it to operate in an open loop condition by introducing a means to control the pulsation of the fuel injectors to a stabilized speed (without fluctuation). For achieve this through some type of fuel control device and then introduce a method to vary the pulses, the amount of fuel injected into the engine can be manually controlled. With the help of an exhaust gas analyzer, many more tests can be performed such as the test of the catalytic converter when an engine is not running in Factor 1, forcing it to do this and then check emissions from the exhaust. The patent of E.U.A. 5214582 describes a motor diagnostic / control system, which is adapted to receive the sequential control signal of the ECU and reproduce it, without modification, while the motor is running. Alternatively, when the engine is not running, it can ignore the ECU signal, while testing the injectors and other engine components for their operating capacity. The device described in this document can not operate in an open-loop mode, that is, • ftiti ?? [ii? 1 itfMíí - ??? In order to operate the injectors according to a modified signal, take the control signal and modify it. The patent specification of E.U.A. 5107428 is an additional injection and ignition tester and is adapted to connect to an engine injector to operate its operating capacity. The device is connected in parallel to the ECU not between it and the injectors. According to the present invention a diagnostic / control device for internal combustion engines of The injected fuel comprises a control system having means for the direct electrical connection to at least one fuel injector of an engine and to an engine management computer, and also means for operating at least one injector independently of the computer of the engine. engine management. In addition, in accordance with the present invention, a method for testing internal combustion engines of injected fuel comprising the steps of providing a control system, electrically connecting the control system directly to at least one fuel injector is provided. a motor instead of an engine management computer normally connected to it, connecting the control system also to the engine management computer, and having the control system operate at least one injector independently of the engine management computer . Now one embodiment of the invention will be described, only to by way of example, with reference to the accompanying drawings, in which: Figure 1 illustrates a fuel injection system controlled by a conventional closed loop computer; Figure 2 similarly illustrates a fuel injection system capable of operating in an open loop mode and including a connected control system in accordance with the invention. Referring to Figure 1, the fuel injectors of a four-cylinder internal combustion engine are illustrated at 10. The control, or pulsation, of the injectors is provided by an ECU 11 powered from the vehicle battery 12 and operating in accordance with the signals received from an oxygen sensor 13, which typically can be located in the exhaust system as close as possible to the engine before any catalytic converter. The ECU 11 is connected to the injectors 10 through cables 9 and to the oxygen sensor via a cable 8. Referring now to Figure 2, a control system provided in accordance with the invention is generally indicated at 14 and It has been introduced "between" the ECU 11 and the injectors 10. In this way, the connection plugs 15 of the normal injector have been disconnected from the injectors 10 and have been replaced by four other cables 16 electrically connected to the control system 14. The oxygen sensor 13 is also connected at 17 to the control system. It will also be seen that one of the disconnected injector plugs 15a is connected at 18 to the control system 14, whereby the latter is also connected to the ECU 11. As a result of these connections, the control system 14 is directly and operably connected to the fuel injectors 10 and can control its operation independently of the ECU 11. However, the ECU must be connected to the control system to provide a reference signal for the program times. When the engine is turned on, it will, by default, run in a "straight" mode allowing the ECU 11 to have full control while keeping the loop operation closed. However, it is now possible to store an injector pulse reading of the ECU 11 and continuously reproduce and manually modify it giving full control of the fuel setting in the open loop operation mode. In this mode, the operation of the oxygen sensor 13 can be verified through the provision of two indicator lights in the control system showing the response of the sensor to enrich or impoverish the running conditions. From this mode, it is possible to start an automatic mode of operation, so the control system will continuously adjust the amount of fuel injected into the engine in response to the readings taken from the oxygen sensor much in the way in which it normally the ECU does 11. However, unlike the ECU, the control system 14 has no connection to a sensor arrangement, which provides conflict information during fault conditions. The main units within the control system 14, in addition to the control buttons 3 and the indicator lights 4 in a console 30, are a microprocessor 31, injector actuators 32, a voltage regulation suppression and protection device 33, a ECU injector input interface 34 and oxygen sensor interface 35. Control system 14 can not feed any signal back to the ECU thus eliminating the possibility of damage to it. A number of diagnostic tests can be performed with the system in view of the open loop mode where it is capable of operation. For example, the catalytic converter can be tested by controlling the fuel supply to the injectors so that the correct AFR can be achieved and maintained, and thus the carbon monoxide or other emission content of the catalytic converter can be verified using a gas analyzer. The oxygen sensor 13 itself can be verified as previously indicated by deliberately driving the enriched and depleted motor and verifying if the correct signals are received from the sensor. Also, if the system 14 is used to ensure that the engine is running at Factor 1, ie an AFR of 14.75: 1 and the engine is able to achieve this independently of the ECU, this can confirm that the ECU is responsible if Other possible failures have been eliminated. Air leaks from the inlet manifold can be detected when a resulting low vacuum leads to a low fuel introduction and a bad engine run. The control system can be used to increase the operating time of the injector to determine if the engine will then run correctly, thus helping to diagnose if an air leak is present. Similarly, fuel fed to a single cylinder can be increased to help diagnose an air leak while allowing the ECU 11 to control the remaining cylinders. The control system can be used to operate the injectors in a pulsed mode when they are placed in a cleaning bath. Preferably, the system will be supplied with adapters that allow it to be used in engines that have more than four cylinders. The system is simple to operate giving a set of instructions for an operator to perform several tests, the results of those tests being easily available and / or computable from the test results. The device can be extremely compact and lightweight enough to be portable with attached cables of sufficient length that an operator can sit on the driving seat of the vehicle • "* - * - *> - **** •« * «* to conduct the tests In an alternative mode, a system according to the invention can be permanently installed in a vehicle and, with signals received from the appropriate sensors, it can automatically determine when to take control of the injectors and when to return said control to the ECU.Thus, for example, the device can control the fuel injection according to the predetermined parameters such as when the engine is in crossing with the established fuel conditions and the vehicle at a stable speed. Said operation is completely controlled through the microprocessor without the need for control switches or indicator lights. In this way, the device could operate diagnostically, but as a control device and optimize the fuel economy and emissions of escape. The lifting cable devices can be directly connected in the vehicle wiring, and the oxygen sensor will be equipped to the exhaust. Thus, said installation can be used effectively to improve vehicles injected with fuel older to a closed loop system for the verification of exhaust gas to achieve a more economical operation with fewer hazardous emissions.

Claims (14)

1. - A diagnostic / control device for an internal combustion engine of injected fuel having a motor management computer (11), the device comprises a control system (14) having means (34) to receive a signal from the computer of engine management (11), while the engine is running and to modify the signal separately to control the operation of the engine.

2. A device according to claim 1, having means (32, 16) for the electrical connection directly to at least one fuel injector (10) of a motor and additional means (31) to drive at least an injector (10) according to the modified signal.

3. A device according to claim 1 or claim 2, wherein the control system (14) is adapted to be connected between the engine management computer (11) and the plurality of injectors (10) in an engine by disconnecting the normal motor injector connection plugs, (15), and replacing them through a plurality of cables (16) electrically by connecting the control system (14) directly to the injectors.

4. A device according to any of claims 1 to 3, including means (35) for connection to the control system (14) of an oxygen sensor (13) in the system ñiMMUÉ engine exhaust.

5. A device according to claim 3, wherein means (15a) are provided for the connection of a disconnected injector plug (15), to the control system 814) so that the control system is connected to the engine management computer (11) to provide a reference signal for program times.

6. A device according to any of the preceding claims, wherein the control system includes a microprocessor 831).

7. A device according to claim 6, wherein the microprocessor (31) can be connected to the engine management computer (14) so that the signals can not be fed back to the computer to avoid the damage to 15 same.

8. A device according to any of the preceding claims, wherein the control system (14) includes a console (30) having an arrangement of control switches and indicator lights for diagnostic use of the operator.

9. A device according to any of the preceding claims, including adapter means enabling the control system (14) to be connected to all the injectors of the engine having a variety of cylinder numbers.

10.- A device according to any of the 25 preceding claims, where it is sufficiently compact To be portable and with cabl'es / connectors of sufficient length to allow an operator to sit in the driver's seat of the vehicle to drive the tests on the engine.

11. A device according to any of claims 1 to 3, being adapted for permanent installation within a vehicle and adapted to control the operation of the engine automatically according to the predetermined parameters.

12. A method for testing an internal combustion engine with injected fuel having a motor management computer, using the device of claim 1, comprising the steps of providing a control system, electrically connecting the same directly to At least one fuel injector of an engine in place of the engine management computer normally connected to it, connect the control system also to the engine management computer, and modify the engine signal to make the system Control actuate at least one injector according to the modified signal.

13. A method according to claim 12, wherein the control system is electrically and operably connected between all the fuel injectors of a motor, and a motor management computer, storing an injector pulse reading of the engine management computer and continuously reproducing said reading and modifying it to give control of the adjustment in an open loop operation mode.

14. - A method according to claim 12 or claim 13, which includes, in an automatic mode of operation, the step of continuously adjusting the amount of fuel injected into the engine in response to the readings taken from an oxygen sensor to thereby achieve a air to fuel ratio predetermined. jgjgl ^ yigg ^