ES2224815B1 - COMMON RAIL INJECTOR TEST FOR DIRECT HIGH PRESSURE INJECTION FOR INTERNAL COMBUSTION DIESEL ENGINE. - Google Patents

Abstract

Apparatus for checking the high-pressure injectors common rail system for diesel engines in such a way that through a method of loading and unloading of condensers the injector is activated in the same way that it does in its operation in the vehicle, being able to vary the time and frequency of activation of the injector to reproduce the same working conditions as in the vehicle. The equipment consists of several internal operating blocks (figure 1): Power supply, control stage, power stage, fuses and a light switch, all mounted in a sturdy box to work in mechanics workshops.

Description

Common rail injector tester high pressure direct injection of a diesel combustion engine internal

The present invention relates to a tester of common rail injectors.

As is known, high injection systems "common rail" pressure consist of several injectors (so many as number of engine cylinders) to supply fuel to An internal combustion engine.

When one or more of these injectors of "common rail" does not work or does not work properly can give internal combustion engine failures such as excessive consumption fuel, white smoke, black smoke, unstable idle, lack of  power, difficult starting, etc., or in the worst case, they can pierce the piston if the injector gets caught in the open position.

Currently, when one or more of these "common rail" injectors do not work properly, and do not You know which one is wrong, you usually proceed to replace all, since there is no way to verify them.

In accordance with the present invention, provides an apparatus for checking the operation of "common rail" injectors. This device works in such a way so that through a loading and unloading method of capacitors the injector is activated in the same way it does in its operation in the vehicle, being able to vary the time and the injector activation frequency to reproduce them working conditions that occur in the vehicle. This way you You can check the individual operation of each injector.

Composition of the different blocks

Figure 1 shows the block system from which the nozzle check apparatus of "common rail".

It shows three blocks:

a) Power supply (1):

The goal is to obtain two voltage values, one of 84 volts (11) of direct current to power the injector through the output stage (2).

And a second voltage of 12 volts (12) of direct current to power the circuit itself apparatus.

b) Control stage:

It consists of a monostable circuit (3), a stable circuit (4) and an inverting amplifier (5) fed to 12 volts dc

c) Power or output stage (2):

It consists of two transistors used as preamplifiers of the previous stage and powered at 12 volts dc, amplify the signal to get the current values suitable at the circuit output.

Figure 2 shows in detail the circuit of the power supply.

Figure 3 shows in detail the circuit of the control stage and exit stage.

Embodiment of the invention of the tester "common rail" injectors

As previously mentioned, the objective is to simulate the operation of the injectors in the same way which are activated in the vehicle during operation. Thus, the apparatus charges and discharges condensing elements so that the injector is activated in the same way it does during operation in the vehicle.

To achieve such an objective the invention is basically composed of three stages or circuits.

a) Power supply: the source of food (1) has the mission of obtaining or taking out two values of voltage, one of 84 volts dc (11) to power the injector to through the output stage (2) and a second voltage of 12 volts cc (12) to feed the circuits stable (4), monostable (3), amplifier (5) and previous stage (6). It feeds on an input of 220 volts with switch and two fuses, one of which protects the input to the primary of the transformer and the other protects the current output of the injector.

The voltage of 84 volts cc is achieved with two 42 volt sources mounted in series.

The voltage of 12 volts cc is achieved with a single source through a voltage divider and a regulator 12 volt voltage

b) Control stage: the control stage is formed by a stable circuit (4), a monostable circuit (3) and an inverting amplifier (5) powered at 12 volts dc. This control stage elaborates, varies and amplifies the value of the signal.

A first timer working as a circuit stable generates a negative impulse of 0.5 ms. This signal once amplified and inverted by an inverting amplifier circuit, control the current values of transistors TR 1 and TR 3 to get the necessary current of the T 1 impulses. This Timer also regulates the signal frequency between 1 Hz and 10 Hz by means of potentiometer P1 and generates the trip of another Second timer that works as a monostable circuit.

This other circuit generates a variable signal in the time through the potentiometer P2 which, once amplified and inverted twice, it will control the current values of the TR 2 and TR 4 transistors to achieve the necessary current of T2 impulses.

The inverting amplifier circuit outputs two indicator lights (LD1 indicates the frequency of T1 + T2 and LD2 indicates the time of T2).

c) Power or output stage:

Two medium transistors are used power as amplifiers in the previous stage and fed to 12 volts amplify the signal to the appropriate values to polarize The bases of power transistors.

Two potentiometers P3 and P4 adjust the value of the base currents of each of the transistors to get the proper current values at the output of the circuit.

The output transistors work in switching with each respective pulse in the base, so they can never work both simultaneously since the impulses T1 and T2 are 180 ° out of phase with respect to each other.

This makes the output of the transistors, that is, in the collectors that are attached, there is a sum of the two periods T1 and T2.

This output current activates the injector of the same way it does during its operation in the vehicle, thus being able to check its status.

The equipment is completed with a metal box designed to work under the conditions of a workshop mechanics.

Claims (3)

1. Common rail high pressure direct injection nozzle checker for internal combustion diesel engines characterized in that it generates a signal to activate the common rail injector as produced in the vehicle through loading and unloading of capacitors in order to test and diagnose the operation of the injectors outside the vehicle, the frequency and the activation time of the injector coil or excitation piezo may vary. 2. Common rail high pressure direct injection injectors for internal combustion diesel engines according to claim 1, characterized in that it includes two potentiometers (frequency potentiometer and injection potentiometer) to vary the frequency and the activation time and assess the correct operation of the injector in the entire operating range. 3. Common rail high pressure direct injection injectors for internal combustion diesel engines according to any of the preceding claims, characterized in that it activates the injectors through discharge of condensers to simulate the vehicle control unit and be able to reproduce the same activation signal that is used in the vehicle.