JPS6253699B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a mechanism for varying the amount of fuel supplied into a combustion chamber of an internal combustion engine, an accelerator pedal for varying the amount of fuel supplied, and an amount of fresh air supplied. An internal combustion engine having an air measuring mechanism for detecting the amount of air as the actual amount of air, an exhaust gas return conduit leading from the exhaust gas conduit system of the internal combustion engine to the intake conduit system, and a mechanism for metering the amount of exhaust gas return. This invention relates to a fuel supply device for.

Problems to be Solved by the Invention In order to reduce harmful components in the exhaust gas of an internal combustion engine, feedback of a predetermined amount of exhaust gas serves as an extremely effective means for reducing, in particular, NO _x components. The supply of gases that do not participate in combustion causes a reduction in the combustion temperature, so that relatively little NO _x is produced. Furthermore, the amount of ejected exhaust gas is reduced. However, this reduces the efficiency of the internal combustion engine due to the required gas exchange operations. Furthermore, at low rotational speeds, the engine's operation becomes sluggish, especially when idling. On the other hand, a relatively large amount of exhaust gas can be fed back even during smokeless combustion in order to reduce the emission of NO _x even in the partial load range. Rather, a large amount of exhaust gas must be fed back.

Despite the fact that NO _x emissions also decrease as combustion temperature decreases, NO _x
The divergence is particularly high and therefore particularly dangerous. This is because street traffic mainly involves driving within a partial load range, and exhaust gas regulations are strict. In contrast, exhaust gas regulations are relatively lenient for long-distance driving, where maximum power is required under full load and the accumulation of harmful exhaust gases is relatively small.

The object of the invention is to ensure that the oxygen content of the gases in the combustion chamber of the engine is always sufficiently high, so that smokeless combustion takes place and, in particular, as much exhaust gas as possible is removed in order to obtain combustion with low NO _x emissions. The goal is to improve the fuel injection system so that it can provide feedback.

Means of the Invention for Solving the Problem The gist of the present invention for solving this problem is that a fuel injection mechanism is provided for injecting fuel into the combustion chamber of an internal combustion engine operating in a diesel combustion mode, and the internal combustion engine is operated in all operating ranges. In order to feed the total charge required by the cylinder into the combustion chamber without throttling, the mechanism for metering the exhaust gas return amount is installed in the intake pipe upstream of the opening of the exhaust gas return conduit into the intake pipe. or in the exhaust pipe or in the exhaust gas return pipe downstream of the branch point of the exhaust gas return pipe from the exhaust pipe, the throttle flap being actuated by the accelerator pedal. and a mechanism is provided for detecting the actual amount of fuel injected into the combustion chamber of the internal combustion engine by the fuel injection mechanism, and detecting the actual ratio of the actual amount of air to the amount of actual fuel. and a mechanism for comparing the actual ratio with a target value, and the mechanism for detecting the actual ratio:
The present invention is configured to operate the mechanism for changing the amount of fuel depending on the comparison result.

According to the invention, a single control device provides a supply of combustion air that is perfect for the injected fuel, or a fuel supply that is commensurate with the amount of intake air. Atmospheric pressure prevails in the intake pipe at least immediately before the air amount measuring mechanism, and negative pressure generated by the intake stroke prevails within the intake manifold. In contrast, a certain overpressure prevails in the exhaust pipe, which is generated by the exhaust pipe top or by a throttle flap arranged downstream of the exhaust gas return line. This overpressure is in each case large compared to atmospheric pressure.
In this way, a natural pressure difference is created from the exhaust pipe to the intake pipe, which results in a controllable exhaust gas return flow.

In summary, according to the invention, the exhaust gas return (EGR) is controlled as a function of the load (fuel amount) or fresh air as a function of this. In that case, the engine is supplied with fuel and fresh air with a predetermined excess air ratio, the remainder of the cylinder charge is completely filled by the exhaust gas return, and the generation of harmful NO _x is therefore prevented over the entire operating range. be suppressed as much as possible over the period.

In an advantageous embodiment of the invention, a throttle flap is arranged as a device for pressure control, which produces a pressure drop in the intake pipe, and the exhaust gas return line flows downstream of this throttle flap into the intake pipe. It's open. However, instead of a throttle flap in the intake pipe, a throttle flap in the exhaust pipe or in the exhaust gas return line can also be used, so that the exhaust gas filter is matched as well as possible by the pressure ratio. It can generate an yield back. In this case, it is advantageous if the throttle flap cooperates with an air quantity measuring device for the quantity of fresh air flowing through the intake pipe. In order to increase the engine power, a gas pump (supercharger) is arranged in the intake pipe behind the opening of the exhaust gas return line. In this case, since an air amount measuring mechanism is used, there is no need to provide a control device related to supercharger pressure.
This is because in any case the amount of fresh air taken in is measured and compared with the amount of fuel injected.

According to the present invention, the amount of air can be used as a control parameter. In the present invention, the aperture flap can be arbitrarily adjusted by an accelerator pedal,
In particular, the output value of the air flow measuring device serves as a control parameter for the throttle flap. In one embodiment of the invention, the throttle flap cooperates with an electronic control device in which the air flow is controlled in accordance with an electronic division of the air supply per unit time and the engine speed. A flow rate/work cycle signal is generated, which serves as an injection reference value.
In this case, a magnetic valve serves as the injection device, the opening time and frequency of which correspond to the injection reference value.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In all the embodiments described below, air is drawn in by the engine 1 via an air cleaner 3, an air quantity measuring mechanism 4 and a throttle flap 5 through an intake pipe 2. Exhaust gas from the engine 1 is guided through an exhaust pipe 6. A muffler 7 is arranged in the exhaust pipe 6. This engine 1, which operates in diesel mode, is supplied with diesel fuel via a line 9 from a fuel injection pump 55, which is injected directly into the cylinders of the engine 1 or into the front chambers of the cylinders. The exhaust pipe 6 and the intake pipe 2 are connected to each other via an exhaust gas return pipe 10, so that, depending on the pressure ratio in the exhaust pipe/intake pipe system, more or less exhaust gas is transferred via the exhaust gas return pipe 10 to the intake side. flows into. The pressure ratio is determined primarily by the degree of opening of the throttle flap 5. Fresh air flows in through the air filter 3 according to the engine speed, or in other words, the amount charged into the cylinder, but corresponds to the volume of air that cannot flow in through the air filter 3 depending on the opening degree of the throttle flap 5. Exhaust gas enters via an exhaust gas return conduit 10 . To control this pressure ratio, a throttle flap 11 (shown in broken lines) is arranged in the exhaust pipe 6 downstream of the branch point of the exhaust gas return line 10, or a throttle flap 12 is arranged in the exhaust gas return line 10. . The pressure difference between the intake side and the exhaust side of the engine 1 consists of a predetermined negative pressure that is constantly generated in the intake pipe 2 due to the suction action, and a slight overpressure that is constantly generated in the exhaust pipe due to the extrusion of exhaust gas. arises only by. Depending on the degree of throttling effect of the muffler 7 or the air cleaner 3, this pressure difference can be further increased. This pressure difference is further increased by the supercharger 13. Supercharger 13
is arranged in the intake pipe downstream of the opening point of the exhaust gas return conduit 10. In the device according to the invention, the amount of fresh air necessary to effectively burn the fuel supplied by the fuel injection mechanism 8 is supplied to the engine 1 via the air cleaner 3. The remaining gas volume to be drawn in by the engine 1 is filled by the feedback exhaust gas. Output increase or NO _x
For mitigation, a cooler 14 can be provided in the intake pipe 2 behind the supercharger.

In the embodiments shown in FIGS. 1, 2 and 3, the fresh air quantity determined by the throttle flap 5 and, to a certain extent, by the engine speed serves as the reference input for the control device. For this purpose, the throttle flap 5 is adapted to be coupled to the accelerator pedal 15 of the vehicle. Instead of aperture flap 5, aperture flap 11 or aperture flap 1
2 can of course be operated by the accelerator pedal 15.

In the embodiment shown in FIG. 1, a fuel metering valve 16 is actuated by the air amount measuring mechanism 4, and the fuel metering valve 16 defines the suction amount of the distributing injection pump 17. In the embodiment shown in FIG. The air quantity measuring device 4 has a plate 20 arranged at right angles to the flow direction, which plate 20 acts via a lever 21 on a metering spool 22, which controls the fuel pre-discharge. control the fuel flow of the fuel pump 23. The pressure of the fuel predischarge pump 23 is regulated by a pressure control valve 24 . A constant return adjustment force of the plate 20 is produced by pressure fluid acting on the back side of the metering spool 22. This pressure liquid is supplied to the fuel front discharge pump 23
and can be adjusted by a pressure control valve 24. Metering spool 2 independent of back pressure
2, a differential pressure valve 25 is connected downstream to the fuel metering valve 16, which cooperates with a diaphragm 27, which on one side by the pressure prevailing upstream of the fuel metering valve 16 and on the other side by the pressure prevailing after the fuel metering valve 16; Depending on the pressure difference across the valve 16, the spring 28
loaded by.

A pressure accumulator 30 is connected to the conduit 29 between the differential pressure valve 25 and the distributing injection pump 17 which operates intermittently.
7 receives a metered amount of fuel each time it closes the suction port 31 and transfers this amount to the pump working chamber 3 of the dispensing injection pump 17 when the suction port 31 is opened.
Transfer to within 2. In this way, uniform fuel supply is achieved. A centrifugal regulator 33 serves for the final speed or safety cut-off adjustment, which centrifugal regulator 33 controls a valve 34 in the conduit 29. In short, in this fuel injection mechanism 8, a predetermined amount of air is regulated by the throttle flap 5 and the engine speed via the air amount measuring mechanism 4, and a predetermined amount of fuel is injected into the fuel metering valve 16 in accordance with this. This predetermined amount of fuel determines the filling amount of the distributing injection pump 17. The fuel injection quantity is therefore always adapted to the fresh air quantity, which results in effective combustion.

In the embodiment shown in FIG. 2, the air quantity measuring mechanism 4 has a dam flap 35 whose shaft 36 is connected to a contact 37 of a potentiometer 38 to which a constant DC voltage is applied.
is connected to. This potentiometer 38 has an exponentially increasing characteristic and therefore a control voltage that increases at least approximately linearly with the air flow rate, which control voltage is applied as a reference input to an electronic control device 39. Given. This electronic control device 39 controls four electromagnetically actuatable fuel injection valves 40, each one of which is connected to one engine cylinder or Direct injection into the corresponding vestibule. These fuel injection valves 40 can also be designed as pump nozzles or high-pressure injection valves. The control device 39 generally has a monostable multivibrator, and the monostable multivibrator is triggered by a signal transmitter (not shown) connected to the crankshaft of the engine 1 to control the opening time and thus the opening time. The amount of fuel flowing out from the fuel injection valve 40 is defined. The injection amount is adjusted each time by known means (not shown). The fuel injection valve 40 is supplied with fuel by a fuel pump 41 , the prepressure of which is regulated by a pressure control valve 42 .

In the embodiment shown in FIG. 3, the signal from the air flow measuring mechanism 4, which is the same as in the embodiment shown in FIG. I get a signal. An in-line injection pump serves as the fuel injection mechanism 8. A transmitter 45 is disposed on the camshaft of the in-line injection pump, which rotates at a speed corresponding to the engine speed. The rotational speed is then given to the control device 39. The actual injection quantity is indicated by a potentiometer 46, which is connected to the adjustment rod 4.
It has a contact 48 connected to 7. The potentiometer 46 has a linear characteristic, and therefore, the voltage applied to the control device 39 is determined based on the premise that the moving distance of the adjustment rod 47 has a linear relationship with the amount of fuel to be measured. , which corresponds linearly to the amount of injected fuel. The shaft 49 of the aperture flap 5 is connected to the eccentric 50 of the adjusting lever 51 of the adjusting rod 47, so that the movement of the aperture flap 5 by the accelerator pedal 15 results in a displacement adjustment of the adjusting rod 47. This coarse adjustment of the injection quantity in accordance with the actual value is carried out by modifying the reference value by means of the adjusting magnet 52, which reference value is then adjusted via the electronic control unit 39 by electronic division of the air flow rate/working cycle. It is defined by the position of the rod 47, and thereby,
Both these values come into harmony. For this purpose, a bridge circuit with, for example, a proportional resistance in the electronic control device is useful, the adjusting magnet 52 being located in the diagonal of the bridge. In this case, a safety shut-off adjustment and a final shut-off adjustment are generally performed by means of a centrifugal regulator 53.

The control device shown in FIGS. 1 to 3 can also be used in a spark ignition engine having a fuel injection device.

Effects of the Present Invention According to the present invention, the amount of exhaust gas returned is controlled depending on fresh air, and at this time, fuel and fresh air are supplied to the engine at a predetermined excess air ratio, and the remainder of the cylinder charging amount is used as exhaust gas. Since it is completely filled by the return amount, the entire cylinder charge is fed into the combustion chamber without being throttled, and the generation of harmful NO _x is suppressed as much as possible over the entire operating range.

[Brief explanation of the drawing]

FIG. 1, FIG. 2, and FIG. 3 are schematic diagrams showing each embodiment of the present invention. 2...Intake pipe, 4...Air amount measuring mechanism, 5...
Throttle flap, 6... Exhaust pipe, 8... Fuel injection mechanism, 10... Exhaust gas return conduit, 11, 12... Throttle flap, 15... Acceleration pedal, 16... Fuel metering valve, 17... Distribution type Injection pump, 20...
Plate, 21... Lever, 22... Metering spool, 2
5...Differential pressure valve, 27...Diaphragm, 30...
Pressure accumulator, 33... centrifugal force regulator, 35... dam flap, 37... contact, 38... potentiometer, 39... control device, 40... fuel injection valve, 45... transmitter, 46 ... Potentiometer, 47 ... Adjustment rod, 51 ... Adjustment lever, 52
...Adjustment magnet.

Claims (1)

[Claims] 1. A mechanism for changing the amount of fuel supplied into the combustion chamber of an internal combustion engine, an accelerator pedal for changing the amount of fuel supplied, an air measuring mechanism for detecting the amount of fresh air supplied as an actual amount of air, and an internal combustion engine. A fuel supply system for an internal combustion engine of the type that is provided with an exhaust gas return line leading from the exhaust line system to the intake line system and a mechanism for metering the amount of exhaust gas return, operating in the diesel combustion mode. A fuel injection mechanism is provided for injecting fuel into the combustion chamber of the internal combustion engine, in order to supply the exhaust gas into the combustion chamber without throttling the total charge required by the cylinders of the internal combustion engine in all operating ranges. Said mechanism for metering the return amount is provided in the intake pipe upstream of the opening of the exhaust gas return pipe into the intake pipe or in the exhaust pipe or in the exhaust gas return pipe downstream of the branch point of the exhaust gas return pipe from the exhaust pipe. Consisting of throttle flaps 5, 11, and 12 provided at only one location, this throttle flap is operated by the accelerator pedal and is injected into the combustion chamber of the internal combustion engine by the fuel injection mechanism. a mechanism is provided for detecting an actual amount of fuel, and a mechanism is provided for detecting an actual ratio of the actual amount of air to the actual amount of fuel and comparing the actual ratio to a target value;
and the mechanism for detecting the actual ratio is the mechanism 1 for changing the fuel amount according to the comparison result.
1. A fuel supply system for an internal combustion engine operated by a diesel combustion method, characterized in that the system is configured to operate a fuel supply system for an internal combustion engine operated by a diesel combustion system.