CS210370B1 - Appliance for the control of the injection time of electronic fuel injection device - Google Patents

Abstract

1514348 Automatic control of fuel injection WISSENSCHAFTLICH-TECHISCHES ZENTRUM AUTOMOBILBAU-KARL-MARX-STADT VEB 12 Aug 1976 [18 Aug 1975] 33569/76 Heading G3N A fuel injection system for a diesel engine comprises means for generating a first electrical signal of sawtooth waveform having a value changing linearly in dependence on the angular displacement of the engine crank-shaft from a datum position, means to generate two second electrical signals having instantaneous values dependent on the engine loading and engine speed, means to multiply these signals together and produce a product signal which is compared with the first signal such that when the product and first signals are equal a fuel injection pulse commences and is terminated when the first signal equals a reference signal. As shown a cam 11 mounted on the crank-shaft of the engine causes sensor 10 to output a linearly changing waveform shown in Fig. 3a. An accelerator pedal transducer 25 provides an engine load signal which is a linearly rising voltage V α . A speed transducer comprising disc 21 and sensor 20 produce a voltage V # which rises linearly with speed. Multiplier 30 provides the product Up which is used in comparator 40 to determine when the sawtooth waveform equals the product voltage Up and the reference voltage U b , which is zero in the present case, to produce the injection pulse PO, Fig. 3a. To ensure that the injection pulse terminates a predetermined angle before TDC regardless of speed, a displacement voltage U v is derived from the engine speed signal and subtracted from the sawtooth waveform voltage U # . Other corrections can be applied by operating on the signals before applying them to the comparator to provide maximum fuel level, temperature compensation and the like.

Description

BACKGROUND OF THE INVENTION The present invention relates to an apparatus for controlling the injection time of an electric fuel injection apparatus, in particular for diesel internal combustion engines with electrically controlled injection valves and a constant pressure propellant propellant delivery device with a sawtooth voltage sensor arranged on a cinema shaft. is in the injection. depending on the angle of rotation of the crankshaft, furthermore with a non-dragging device dependent on the speed of rotation of the crankshaft. which consists of a pulse transducer and a rotation speed transducer with an injection pulse comparator transmitting at rotation speed.

There is known a device for electronic control of ignition and / or fuel injection in machines so. internal combustion engines of the above-mentioned type, see DE-OS 2 413 014. For the use of the fuel injection device control device, the moment of the start of injection is determined by means of the comparator and a timing member is excited. substances, adjustable by the sum of several parameters. A non-conforming device in Diesel engines is that it is not secured to a constant injection end at your speed and

It is known from DD-Pat. No. 89,596 that the propellant control system, which determines the injection molding and the control injection port, is controlled by the voltage emitted by the multiplier / whose inputs or inputs. the voltage of which is transmitted by the accelerator position sensor, the crankshaft rotary sensor and other correction voltages. The fuel control system controls the injection rates by controlling the fuel flow to the still open injection nozzles.

The known solution described has the disadvantage that it does not allow the injection of propellant in the parent engines, either in terms of time or in relation to the rotation of the crankshaft.

Furthermore, an electrically operated injection system for diesel internal combustion engines of DE-OS No. 2,555,603 with a pump-nozzle assembly according to DE-OS No. 2,126,787 is known.

The filling time of the electrically controlled injection device, which corresponds to the following injection quantity, begins so that at each possible filling time a constant end of the filling time is reached with the following constant start of injection relative to the camshaft or crankshaft position.

To carry out this control procedure, a cam switch is assigned to the camshaft, which controls or releases the camshaft. In the closed state, it excites a digital-to-nano converter which converts the pulses derived from the crankshaft position into voltage proportional to its angular rotation when the switch is turned on.

The pulses derived from the position of the crankshaft are dependent on the rotation speed which is applied to the first input of the multiplier and also to the regulator, which determines the filling time and thus the injection quantity.

In the regulator determining the filling time, the voltage dependent on the opening angle of the glass damper is added together with the voltage dependent on the rotation speed and the output voltage is applied to the second input of the multiplier.

The output voltage multipliers together with the voltage proportional to the angle of rotation of the crankshaft are supplied to one comparator input, the start of the filling being triggered by the comparator at the same time of the two mentioned voltages, by comparing the impactor to the bistable control stage. to one position, which is then swung back to its original position by opening the control switch again.

By tilting the bistable control stage back to the original position induced by the control switch, the end of filling and the start of injection are fixed.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a control device as described above which allows the injection time to be controlled and its position within the injection angle range which is located before and at the top of the work cycle. At the same time, several variables affecting the injection are to be sensed by the control device and processed in dependence on time and angle in order to ensure, in particular at all injection rates and at all engine speeds, a certain end of the injection.

This problem is solved and the above drawbacks are overcome by the injection time control device of the electronic fuel injection device according to the invention, the essence of which is that the output of the voltage to speed converter is connected to the second input of the multiplier. the output of the accelerator pedal is connected, the output of the multiplier being directly or indirectly connected to one of the inputs of the comparator, the other inputs of the comparator being connected to the output of the sawtooth sensor or the reference voltage source and the actuator output for the electromagnetic injection nozzle.

The advantage of the device according to the invention is that it makes it possible to process various information according to its importance depending on the time or angle of rotation of the crankshaft. Injections may have been made both in terms of time and position in the injection range. This ensures that the pponoot is optimal in causing the fuel to flow according to the engine parameters.

The invention will be explained in more detail by way of example with reference to the accompanying drawings.

FIG. 1 shows a schematic circuit diagram of a device according to the invention with a shifting of sawtooth voltage U beta.

Fig. 2a shows the accelerator pedal - voltage U alpha = f (alpha), where alpha is the accelerator pedal travel angle

Fig. 2b shows a voltage-angular velocity U omega = f (n ^) where the crankshaft speed is 1 / min.

Fig. 3 shows a sawtooth voltage diagram over the injection angle range beta with the product voltage and at an injection pulse time of 2 ms. U beta = f (beta)

a) at speed = 500. 1 / min

b) at engine speed n ^ = 2000 rpm crankshaft, where beta is the angle at which fuel is injected.

FIG. 4 is a diagram of the displacement voltage Uv in a speed range for a displacement time of 0.5 ms.

Ob ob] ?. 5 shows a diagram of a sawtooth voltage in the injection angle range beta with the product voltage and injection pulse time 2. ms with correction voltage. «

Fig. 6 shows a schematic diagram of the voltage Ub and the product voltage Up.

wiring for shift ,! by changing the reference

Fig. 7 shows a diagram of the corrected saw voltage with the corrected product voltage for injection molding after the injection pulse at the injection time, ie g ms

a) at speed = 500 rpm

(b) at engine speed n ^ = 2 000 rpm crankshaft.

Fig. 6 shows an extended schematic diagram.

The device according to the invention of FIG. 1 has a sensor 10 which detects a mechanical sawtooth 11 on a crankshaft disk 110 of an internal combustion engine. The sawtooth 11 is formed in the injection angle range β, which amounts to so many degrees of angular rotation of the crankshaft that it overlaps the injection time t při at the largest injection rate and the lowest crankshaft speed, n.

The sawtooth voltage of the U beta sensor 10 starts with the greatest voltage - the initial U beta voltage. and change linearly in the injection angle range beta to zero - final voltage U beta _e . The injection range extends directly over the top dead center of the internal working cycle of the internal combustion engine, so that any functionally required injection time can be squeezed before or after the top dead center. Sawtooth voltage U beta still has a reference value of 100 between the initial voltage U and final beta _and beta voltage U _e.

The accelerator pedal sensor 25 adjusts the position of the accelerator pedal. As the accelerator pedal position increases towards the higher fuel injection, an increasing voltage U alpha is generated which rises from the reference value zero to the highest value (Fig. 2a).

In the same way as the voltage rises! With alpha, a greater amount of propellant is also fed to the combustion thyristor. As a result of the large amount of fuel required)! the high injection time tg and the low injection quantity require less injection time tgg, the position of the accelerator pedal and the corresponding voltage U alpha is a synonymous quantity for the injection time t _EZ . «

AND

By means of a further sensor 20 and a downstream speed-to-voltage converter 22, a sequence of teeth 21 located on the pulse disk 210 is rotated, rotating at the crankshaft speed .alpha. angular velocities that can be linear or can be corrected (Fig. 2b).

This U omega voltage rises from a reference value of zero at a crankshaft speed of zero to a maximum reference value of ten at a maximum speed at a non-linear, uncorrected course. By multiplying the reference values, the voltage U alpha and the voltage U omega must lead to a true statement, respectively. data when compared to the reference value of U beta for the related fig ^alcohol , see Fig. 2b. *

According to statistical dependence the injection time tgz and the respective injection angle The following consideration is given to igZ. 4 -A '- Δ' t

where omega is the angular velocity, phi means the angle of rotation in the family, for example, the crankshaft and t the time in seconds to run. of this angle of rotation.

In this case, at the injection time t _EZ , the angular velocity of the omega crankshaft, the injection angle fgg is obtained.

/ EZ = ^tgZ

According to these mathematical tsulislsstí with synonyms! The magnitudes for the injection time tgg and the angular velocity omega, the voltage U alpha, U omega as factors multiply each other in the product voltage Up. This process is performed in the multiplier JO, at the output of which the multiplied voltage Up appears.

The comparator JO, which senses the straightness (see point P) of the sawtooth voltage and the product voltage Up, as well as the straightness point 0 of the sawtooth voltage U beta and the reference voltage Ub, induces an injection between the reference points P and 0 '.

3a and 3b show these. comparative processes are shown for different revolutions of the crankshaft. In addition, the time scale is selected constant to show different revolutions, from which different widths of the injection angle range beta in FIGS. 3a and 3b, FIGS. 5a and 5b, and FIGS. 7a and 7b. In Fig. 3a, at a speed n = 500 rpm of the crankshaft, the injection pulse time tg lasts 2 ms at a 6 ° crank angle, corresponding to the angular rotation between the points P and O, respectively. injection pulse angle angles.

In FIG. 3b at crankshaft speed n _k = 2000 l / min, it takes time tg = 2 ms pulse injector 24 ° crank rotation angle corresponding to distances ^ o ^ angular displacement between the points P and 0, respectively. the injection angle phi.

In the above described example, the reference voltage Ub = O and simultaneously corresponds to the final voltage U _e .beta sawtooth voltage.

This determines the constant konec end of the pulse injection, since the injection pulse always ends at ρilvin voltage U beta θ.

In practice, it has been shown that, in addition to the injection pulse time tg, a time-constant displacement must be adjustable so that the injection angle phi _E2 can be translated in the injection angle range beta according to the motor. requirements. Such a procedure will be explained with reference to FIGS. 4 and 5.

The following is contemplated. offset 0.5 ms - offset time those - which occurs constant. over the entire speed range.

At a crankshaft speed n = = 500 rpm, the time after displacement γ over the entire displacement angle φ _v = 1.5 °, e.g. No. of ^{th ka} c ^h 2000 ^t / ^min at 6 °.

In order to require that the injection pulse time tg end at all crankshaft rotational speeds at a constant position, the start of injection must be less according to the displacement angle phi for a constant displacement period γ as a function of speed n 1.

This is accomplished by a shear voltage Uv to reduce the level of the sawtooth voltage U beta over the reference voltage Ub, i.e. throughout the injection angle range beta. The displacement voltage Uv is therefore still subtracted from the saw voltage U beta. This is done with the t3 drill · Feeding voltage. The uv is generated by a feed voltage transducer 14 as a function of the speed n of the crankshaft and fed to the adder 13.

In FIG. 4, the displacement voltage Uv is shown with its reference value for a displacement time of γ = 0.5 ms as a function of the crankshaft speed ^. It is clear from the diagram that the reference value for Uv is generated as a function of the otáč crankshaft speed n and the displacement time

1,.,,

In Fig. 5a, with crankshaft rams n = 500 rpm, the tp injection pulse injection time 3 ms is in the range of 6 ^υ crankshaft angle, which corresponds to the angular rotation distance between points t and 0 or phi _f, the injection pulse, and the time the displacement - 0.5 ms, which is located in a range of angular displacement fíy = 1.5 °.

In Fig. 5b at the crankshaft speed, n 1. - 2,000 rpm is the t pulse injection time? ms in the frame of the 24 ° angle of rotation of the crank, which is released. ime. 'i i points 1 and П. respectively. thlu FIP injection pulse. Thereafter, the displacement time γ = 5.5 ms, which is within the range of the angle θx, θ = 6 °.

They are shifted as can be seen from the foregoing, depending on the speed of the crankshaft, while other engine parameters may also be utilized to produce it.

^ο ^ υηιΗί of the injection impulse by the displacement time γ could also be advantageously achieved also by changing the reference voltage Ub. The shear voltage Uv coming from the shear voltage transmitter 14 is superimposed on both the reference voltage Ub and the product voltage Up at the same size. Both the Ub and Up fillings will change in their level due to the sawtooth voltage U beta.

In practice, it has further been shown that there is a time difference between the stroke of the nozzle needle and the hollow injection molding; impulse. This difference was obtained due to the ratio in íuúoičjuo-s.í what _you> й .mu.l · ssшt? Nιóho circuit and as a result, during mechanical: the valve solenoid Luu-lcni. between the debott of the injection pulse, and the injection time .... is also described

Έ2. ´ '' Έ '”to pr-H ^‘ - which represents the correction time .. The effort must be to make the correction, the time you were small to the time t ^ vst; -;

In the direction of rotation to the shaft / shaft, the w / the long time tp. ₇ at an injection angle rw. which is given by the sum of the angle f1 ... of the injection impedance and the correction angle f1,.

· c ¹ .about the dúsiedlíJ. This means that in the product voltage Up, there are load-bearing liner positions U alpha

and the angular velocity U omega, this product voltage Up must be reduced by the correction voltage Uk, since the injection time t t consists of the injection pulse time tg, dependent on the accelerator pedal angle alpha and the correction time t ^. This reading is made in the adder 62 (see Fig. 8). At the same time, however, the sawtooth voltage U beta must also be corrected according to the speed-dependent angles of phi, ^phi k> ^phi EZ> in order to always achieve a constant injection time tg _Z · This is done by subtracting the correction voltage Uk. .

The adder 15 receives the product voltage Up and the correction voltage Uk from the correction voltage transmitter 16 from the multiplier 30. At the output of the mowing of the dot 15, a voltage difference Up minus Uk, applied to the comparator 50, appears. The correction voltage Uk is thus subtracted from both the saw voltage U beta and the product voltage Up.

A sawtooth voltage diagram is shown in Figures 7a and 7b. It shows the time tg = = tg min minus the injection pulse, i.e. the difference between the injection time and the correction time t.. The respective angles figs figs phi _Z and _k can be seen from FIG. 7 for speed - 500 1 / min ^ n = 2000 1 / min. The end of the injection is always at the end of the sawtooth voltage U beta θ. The above diagram shows the reduced sawtooth voltage U beta and the reduced product stress Up. Both were reduced by the value of the correction voltage Uk in the adders 130 and I5 compared to the reference voltage Ub.

The corresponding explanation for Fig. 4 applies to the correction voltage Uk.

With the shifting voltage Uv and the correction voltage Uk, various corrections can be performed, for example influencing the correction times and the injection angle overlap within the injection angle range beta.

The aforementioned correction combination corresponds to a combination of functions as described individually for the examples in FIGS. 5 and 7. The schematic diagram of FIG. 8 allows for displacement and correction simultaneously.

The saw voltage U beta in the adder 130 can be varied by adding both the shear voltage Uv and the correction voltage Uk before it is applied to the comparator circuit 40. All other connections correspond to the details as described in FIGS. 1, 5 and 7.

Due to the fact that the product voltage Up controls the process time in the aforementioned control system, its factors, i.e. the load-dependent voltage U alpha and the angular velocity dependent voltage U omega, are suitable for carrying further corrections.

It is possible to superimpose the speed-dependent U omega voltage, a correction voltage that would reduce the amount of fuel to be fed according to the diesel engine, or possibly trigger a control intervention when the maximum speed is exceeded. The voltage U omega then receives a non-linear, corrected curve depending on the speed and limits the magnitude of the product voltage Up and thus the injection time tg _Z and its proportional injection amounts at the highest load position.

A similar result can also be achieved by limiting the load-dependent voltage U alpha, namely the speed-dependent limitation, which voltage U alpha can still be influenced, for example, by the motor temperature.

The device according to the invention can be used both in motor vehicles powered by a Diesel engine and in all devices in which the Diesel engine constitutes a stationary drive unit, such as small power generators and the like.

Claims (1)

Apparatus for controlling the injection time of an electronic fuel injection device, in particular for diesel internal combustion engines with electrically controlled injection valves and a constant pressure propellant propellant, with a sensor arranged on the crankshaft for sensing a sawtooth voltage that is linear in the injection range crankshaft rotation angle dependent, and a crankshaft speed-dependent voltage generating device consisting of a pulse sensor and a voltage-to-speed converter, downstream of said pulse sensor and with a comparator transmitting sawtooth-to-voltage dependence an injection pulse, characterized in that the output of the speed-to-voltage converter (22) is connected to the second input of the multiplier (30), the first input of which is the output of the accelerator pedal (25) is connected, the output of the multiplier (30) being directly or indirectly connected to one of the inputs of the comparator (40), the other inputs of the comparator (40) being connected to the output of the sawtooth sensor (10); an actuator for the electromagnetic injection nozzles is connected to the output of the comparator (40) with a reference voltage source (Ub).