DE3810750C2 - Internal combustion engine with several throttles in the intake manifold arrangement - Google Patents

Description

The invention relates to an internal combustion engine according to the preamble of Pa entitlement.

An internal combustion engine of this construction is known from DE 35 18 684 C, in which one Intake manifold arrangement is described, which is a series connection of several adjustable Throttles describes, with throttles that can be adjusted jointly also in the individual combustion chamber duel intake manifold sections are provided. These are combustion chamber-specific throttles in the form of a bellows, which is used to reduce the cross-section in the combustion chamber individual suction pipes. The effective size of the bellows can be, for example be changed by applying a vacuum or compressed air, the duration for a control process is in the range of a few 1/10 s. By utilizing the signals of a Knock sensor can knock combustion of the engine due to changes tion of the effective flow cross-section to all cylinders.

From EP 0 089 492, F 02 D 9/02, there is one Internal combustion engine is known, in which both the means of a Accelerator pedals arbitrarily ver adjustable choke as well as the only one via electronic logic bare throttle - both throttles are made in the usual way as throttle valves formed - in a common to all combustion chambers (cylinders) of the machine Suction pipe are arranged, which - not shown there in detail - individual intake pipes for fresh gas in all combustion chambers of the internal combustion engine delivers. The logic processes signals for the speeds of the driven ones Wheels and the internal combustion engine, the intake manifold vacuum, the driving speed speed and the accelerator pedal position for adjustment commands for an engine that be is connected in terms of path to the throttle which can be adjusted by the logic.

With such a fresh gas supply using an electronic Logic makes it possible to optimize the operation of the internal combustion engine for example in terms of reducing fuel consumption or avoidance dens of the spinning of the driven wheels when accelerating. Hold on ten regarding this prior art is that the desired effect by influencing the fresh gas supply to all combustion chambers of the Ma machine is achieved.  

Another regulation or control principle, such as that of Device based on EP 0 113 227, G 01 M 15/00, is used instead a common, identical influencing of a parameter for all combustion chambers targeted changes to parameters of individual combustion chambers, for example the Ignition timing and / or the fuel injection. Such a scheme or control is based on the knowledge that the individual combustion chambers in different dimensions for the power or torque generation of the machine can contribute so that it is appropriate instead of changing a farm parameters of the machine as a whole to first determine the combustion chamber, that requires a change in a parameter, and then selective make this change.

The use of such a combustion chamber-specific regulation for the purpose of Speed stabilization, especially idling speed, by influencing the air ratio, the amount of fuel, the amount of air, the time of injection and the fuel quantity is described in DE-PS 32 24 042, F 02 D 37/02.

Furthermore, a multi-cylinder internal combustion engine is known from DE 31 43 467 A, at the individual cylinder is arranged above in the cylinder-specific intake pipes Throttle valves can be switched off. Switching off the individual cylinders has this way to ensure that a uniform firing order is obtained in the remaining cylinders remains. A regulation of the internal combustion engine for the purpose of speed stabilization or to reduce knocking combustion, with the individual combustion chamber Control elements of this internal combustion engine are not possible.

The invention has for its object an internal combustion engine with the To improve features of the preamble of the claim that while preserving their basic advantages, an adverse influence solution of the operating behavior of the internal combustion engine is also avoided, if, for example, due to tolerances or different ages apparitions how individual combustion chambers work through a logic change in the fresh gas supply can be adversely affected.

The inventive solution to this problem consists in the characterizing Features of the claim.

The invention is based on the finding that the working point of individuals Combustion chambers of the internal combustion engine, for example, are already so lean Area of the air-fuel mixture may be that further leaning leads to misfires by increasing the air supply to this combustion chamber, So the regulation or control, which in itself the optimization of the Betriebswei se the internal combustion engine is intended to apply to this combustion chamber would lead to deterioration.  

Such a deterioration in the operation of individual combustion chambers is shown in of logic avoided by using stored, in it Values present during the previous work cycle of the internal combustion engine the operating parameters only work out such changes for the respective combustion chamber tet that a regulation not only on optimal operation of the whole Machine, but also on optimal operation of the individual combustion chambers follows.

For recognizing and saving the respective mode of operation of the individual firing chambers me can, for example, the uneven running of the Brenn in a conventional manner engine or the indicated pressure in the individual combustion chambers be drawn. Regarding the detection and evaluation of the uneven running of the Brenn The engine can be referred to EP 0 113 227 mentioned at the beginning.

The invention comes with a particular advantage to be used in an injection internal combustion engine, since it is proportional here between the percentage change in the amount of combustion air supplied on the one hand and the change in air ratio 2 achieved. To avoid of fuel deposits on larger wall areas of the intake manifold assembly the fuel injection is immediately before the intake valves of the Combustion chambers made, preferably when the inlet valves are open are. This can be found in the Wei described in DE-OS 36 09 798, F 02 D 3/00 This is done with air support for the injection.

An embodiment of the invention is described below with reference to the drawing explains in which schematically one used to drive a motor vehicle Four-cylinder internal combustion engine is treated with intake manifold injection is equipped with the control according to the invention.

The core of the internal combustion engine, generally designated 1, is formed by the four cylinders 2 , 3 , 4 and 5 , which receive reciprocating pistons (not shown), which in turn work in the usual way on a crankshaft. For fresh gas supply to the cylinders 2 to 5 , the intake manifold assembly 6 is used with the supply of all cylinders common intake manifold 7 and the cylinder-specific suction pipes 8 , 9 , 10 and 11 , which in the cylinders 2 , 3 , 4 and 5 over periodically öff nende and open closing inlet valves 12 , 13 , 14 and 15 . Of course, the cylinders are also provided with an exhaust system that is temporarily connected to the cylinders via exhaust valves; the exhaust system is not shown to increase the clarity of the drawing.

Immediately in front of the inlet valves 12 to 15 , one recognizes injection valves 16 , 17 , 18 and 19 for the supply of fuel. The fuel supply can, as already stated, be carried out according to the construction according to DE-OS 36 09 798, so that this need not be discussed in detail.

The fresh air to all cylinders 2 to 5 runs in the intake manifold arrangement, the series connection of the common throttle valve 21 actuated by the accelerator pedal 20 and a further throttle valve 22 , 23 , 24 and 25 , each arranged in one of the individual intake pipes 8 to 11 are. These individual throttle valves 22 to 25 are adjusted via electric Stellmo gates 26 , 27 , 28 and 29 , which are indicated by broken lines ter movement connection with each of the individual throttle valves 22 to 25 and are controlled by the logic 30 .

At this point, it should be noted that the throttle valve 21 in the context of the invention can also be replaced by seated throttle valves in the individual intake manifolds 8 to 11 on a common drive shaft which is connected to the accelerator pedal.

The logic 30 signals from the throttle position sensor 31 , for example, a potentiometer, and in this embodiment of cylinder-specific sensors 32 , 33 , 34 and 35 for the indicated cylinder pressure supplied. Instead of such pressure signals, the respective mode of operation of the individual cylinders could also be obtained in a manner known per se by evaluating the uneven running of the internal combustion engine. One would then provide, for example, speed sensors or devices for capturing the accelerations of the crankshaft, which it experiences under the influence of the individual cylinders.

From the various signals supplied to it, the logic generates control signals for the motors 26 to 29 assigned to the individual combustion chambers and thus for the fresh air supply to the individual cylinders via corresponding adjustments of the throttle valves 22 to 25 .

For example, if the driver gives an acceleration command via the accelerator pedal that leads to the full opening of the throttle valve 21 , the cylinder-specific throttle valves 22 to 25 are somewhat more in the direction of avoiding excessive fuel consumption or spinning of the wheels of the vehicle driven by the internal combustion engine Closed position, that is, opposite to the throttle valve 21 , moved. Since the logic 30 knows the peculiarities of the individual cylinders by storing cylinder-specific values in this exemplary embodiment of the indicated pressure, it can pivot the individual throttle valves 22 to 25 into different positions by using the stored values, namely in each case in a position that in this embodiment excludes excessive leaning of the mixture in some of the cylinders. The logic 30 thus not only provides for a change in the command given by the movement of the common throttle valve 21 by means of opposing movements of the individual throttle valves 22 to 25 , but also takes over a “change limitation” or “change adaptation” with respect to the individual air flow rates if necessary the throttle valves 22 to 25 assigned to the individual cylinders.

As a rule, the permissible air flow changes from work cycle to work cycle will be around 10%, i.e. the logic limits the changes accordingly. On the other hand, the range of permissible changes is smaller on a cold start; it is then, for example, 5% or less. Therefore, the logic 30 is also supplied with a signal representing the machine temperature via the temperature sensor 36 .

With the invention is thus a way to optimize the operation of a Internal combustion engine by changing the given by a driver Orders created that simple means the individual circumstances taken into account in the area of the individual combustion chambers.

Claims (1)

Intake manifold arrangement for an internal combustion engine with several combustion chambers, consisting of a manifold and several combustion chamber-specific intake manifolds, in which two adjustable throttles are arranged in series, of which a first throttle arbitrarily by commands from a power actuator, and a second throttle via electronic logic that the Commands of the power actuator and signals from sensors for operating variables are processed, adjustable, at least at least the second throttle being arranged in each of the combustion chamber-specific intake pipes fed by the common suction tube, characterized in that the sensor signals from the operating variables of a previous working cycle of each individual combustion chamber Internal combustion engine are processed to individual adjustment commands for the separately controllable, associated throttles in the combustion chamber-specific intake manifolds and that the combustion chamber-individual intake manifolds near the inlet valves parts are provided with a fuel injector.