EP1147300B1 - Electronic engine control system of an internal combustion engine - Google Patents

Description

The invention relates to an electronic engine control of an internal combustion engine according to the preamble of claim 1.

DE 4420946 A 1 describes a control system for metering fuel in an internal combustion engine known, a signal tel is provided for a basic injection quantity starting from Operating state of the internal combustion engine and a signal for a mixture correction, which is the deviation corrected the air / fuel ratio from a desired value. Will continue at least one signal for transition compensation is provided. The transition compensation also helps Acceleration as well as deceleration. The at least one signal for Transition compensation is linked to the signal tel for the amount of fuel to be injected. When determining the at least one signal for transition compensation, an adaptive correction is used considered. The adaptive correction is made by comparing the signal fr for the mixture correction with a reference or by comparing the output signal of the exhaust gas sensor with a reference educated.

Ignition and fuel supply are electronically controlled in modern internal combustion engines. Among other things, lambda probes are used as O ₂ probes in the exhaust gas flow of the internal combustion engine, with which the composition of the exhaust gases is examined and the proportion of air in the intake manifold is corrected in the case of an electronically controlled gasoline injection and, if appropriate, in the case of carburetor engines.

In addition, it is generally known in intake manifold internal combustion engines for changes in engine load Compensation for fuel wall film changes in the intake manifold an acceleration enrichment or to carry out a delay leaning. If a change in load is detected, this becomes by means of a fuel quantity adapter, a predeterminable fuel quantity as an additional fuel quantity for acceleration enrichment or as a reduced fuel quantity for decelerating deceleration adapted to a fuel quantity predetermined by a map control. Such an additional fuel quantity or a reduced fuel quantity is dependent on the degree the engine load change and temperature.

After initialization of acceleration enrichment or deceleration lean these are controlled by a control unit within a certain Time reduced. The control data for this are from the operation of a Internal combustion engine derived. A number of influencing variables, such as fuel quality, coked intake valves and intake manifold wall effects such degradation is not immediately recorded and taken into account so that less favorable operating conditions can occur that can be optimized.

For such an optimization, it is also known in connection with an acceleration enrichment to carry out the enrichment degradation taking into account the lambda probe signal such that after initialization of the enrichment with an O ₂ probe signal corresponding to a relatively lean exhaust gas, the degradation of the enrichment is interrupted and with one Lambda probe signal corresponding to a rich exhaust gas the depletion of enrichment continues. It is therefore a simple interruption of the degradation of the enrichment at an enrichment level which remains constant during the interruption, the degradation being continued according to a predetermined function after the lambda probe signal has changed from "lean" to "rich". Even with such a relatively simple correction intervention during enrichment reduction, even less favorable operating states of the internal combustion engine can occur, which can lead to exhaust test and driving behavior deficiencies in a vehicle and which are amenable to further optimization.

The object of the invention is therefore a generic electronic engine control an internal combustion engine so that the operation of the Internal combustion engine is further optimized in the event of load changes.

This object is achieved with the characterizing features of claim 1 solved.

This is done by means of a with the lambda probe and the fuel quantity adaptation unit associated correction unit in the presence of a "lean" lambda signal within a time the adapted amount of fuel corresponding to an additional fuel quantity at an acceleration enrichment or a fuel shortage in the case of a retardation lean additionally adaptable by a predefinable correction additional quantity. So it will both with an acceleration enrichment and with a deceleration thinning if there is a "lean" lambda signal additionally Adapted fuel as correction surplus. It has been shown that through such an adaptation of a correction surplus an optimized operation of the Internal combustion engine with improved exhaust gas values and more continuous Transitions during load changes is achievable.

In particular, fuel wall film changes in the intake manifold can Intake manifold internal combustion engine according to claim 2 better considered and be compensated.

For a clear representation of the invention, a fuel quantity adaptation device is described above and a correction unit named separately. Preferably However, according to claim 3, the necessary for this in the usual way electronic components and / or electronic functions in one integrated single electronic component of the engine control unit.

Simpler, known lambda probes according to claim 4 are as two-point probes with a digital output for a "lean" lambda signal and one "Fat" lambda signal formed. The correction according to the invention with a Fuel correction surplus amount is made during the adaptation time, when there is a "lean" lambda signal. Lambda probes with a continuous Signal output can be achieved using threshold circuits may also be operated as two-point probes in the above manner.

There are various ways of adding a correction amount determine and specify:

According to claim 5, the correction excess is preferably present the "lean" lambda signal by multiplying the current adapted fuel quantity (additional fuel quantity for an acceleration enrichment or fuel shortage for a delayed leanness) determined with a factor greater than 1. This factor can be greater than 1 as a function of further parameters, preferably the temperature and the degree of load change, be calculated and specified.

Instead of the factor mentioned above or, if necessary, additionally as another Correction can according to claim 6, the correction amount when the "Lean" lambda signal during an adaptation time by adding the adapted amount of fuel with a predefinable correction amount in Art a level shift can be determined.

Instead of the above corrective measures or, if necessary, as an additional correction is proposed with claim 7 that the correction excess at Presence of the "lean" lambda signal by switching to a stored one Correction map can be determined. With such a correction map a basic map and / or a load change map may be replaced or be modulated.

When connecting and evaluating a continuous lambda signal a correspondingly continuously operating lambda probe according to claim 8, a further optimization can take place in that the correction additional quantity is determined by an assigned, constant adjustment.

According to claim 9, the adaptable fuel quantity and / or the adaptation time and / or the correction excess taking into account influencing variables adaptable and calculable to the current conditions. In particular, the temperature and the specific load change process are influencing variables essential. However, there may also be other detectable ones Influencing factors are taken into account, which may be in the engine control anyway be taken into account.

In a specific embodiment, the adapted Amount of fuel as acceleration enrichment or decelerating deceleration by a relatively large, bell-shaped within a relatively short time Short-term share and a layered, relatively smaller, until the end of Adaptation time determined relatively slowly adjustable long-term portion. With the invention The long-term component is influenced here by the additional correction amount because within the short time of a suitable short-term portion, an over a "lean" lambda signal detectable response to a load change regularly not yet available.

The invention is explained in more detail with reference to a drawing.

In the single figure, the adapted amount of fuel is plotted over time in a diagram a), the plus sign denoting an additional fuel amount and the minus sign denoting a reduced amount of fuel. Below diagram a), a diagram b) assigned to diagram a) is shown, in which the lambda signal of a lambda probe, preferably designed as an O ₂ probe, is plotted over time.

In diagram a) with B is the adaptation time with an acceleration with a Acceleration enrichment shown. The adapted amount of fuel is 1 shown in diagram a) with a solid line and is represented by a relatively large short-term portion bell-shaped within a relatively short time 2 and a superimposed, relatively smaller one, until the end of the adaptation time B determined relatively slowly adjustable long-term component 3.

In the presence of a "lean" lambda signal on the lambda probe, accordingly Diagram b) of FIG. 1 shows the adapted fuel quantity 1 .mu.m a predefinable correction additional quantity 4 is additionally adapted. Like this the 1 by comparing the two diagrams a) and b) can, the adaptation by means of the correction additional quantity 4 only takes place in this way long until there is no longer a "lean" lambda signal at the lambda probe.

The curve shape of the adapted fuel quantity 1 without such a correction is shown in dashed lines in diagram a) of FIG. 1.

The correction surplus 4 can here, for example, when the "lean" lambda signal is present by multiplying the currently adapted Amount of fuel 1, i.e. H. the additional fuel quantity in the case of those just considered here Acceleration enrichment, determined with a factor greater than 1 become. This factor greater than 1 can in turn be a function of further parameters, such as the temperature and / or the degree of load change, be calculated and specified.

On the right side of diagram a) of FIG. 1 and accordingly on the right side of diagram b) of FIG. 1 is the reverse case a delay lean on a delay during an adaptation time V shown. Corresponding to that in connection with the acceleration enrichment Correction described here is also present a "lean" lambda signal within the adaptation time V an adapted Amount of fuel 6 corresponding to a reduced amount of fuel in the present case Delayed emaciation by a predefinable correction amount 5 additionally adapted. Here too, the additional adaptation is carried out using the Correction excess 5 stopped as soon as no "lean" lambda signal at the Lambda probe is present. According to the acceleration enrichment the correction additional quantity 5 can also be present here, for example the "lean" lambda signal by multiplying the reduced fuel quantity can be determined with a factor greater than 1, this factor also greater than 1 in turn as a function of other parameters, such as. B. the temperature and / or the degree of load change, can be calculated and predetermined.

The lambda probe here is preferably a two-point probe with a digital one Output designed for a "lean" lambda signal and a "rich" lambda signal. This lambda probe is one with the electronic components Fuel quantity adapter and / or a correction unit, which in an electronic engine control unit are integrated, the Lambda probe in the exhaust gas flow of the internal combustion engine a lean mixture can sense.

With the correction excess 4, 5 according to the invention, the long-term portion becomes here 3 of the adapted fuel quantity 1 influenced, because within the short Time of a suitable short-term component 2 a via a "lean" lambda signal detectable response to a load change is usually not yet available.

Claims (10)

1. Electronic engine control of an internal combustion engine, for the parameter-dependent control of a base mix quantity of a fuel/air mix which is suitable for the current operating state of the internal combustion engine between a lean mix, based on the current combustion situation, with a low proportion of fuel, and a rich mix, with a higher proportion of fuel, and for controlling further functions, in particular the ignition function, having a device for adapting the fuel quantity, by means of which a predeterminable quantity of fuel, as an increased quantity of fuel for acceleration enrichment or as a reduced quantity of fuel for deceleration depletion to the base mix quantity predetermined by the engine control, can be adapted and eliminated again within a certain time, and having a lambda sensor as O₂ sensor in the exhaust-gas stream of the internal combustion engine, by means of which a lean mix can be sensed with a "lean" lambda signal being emitted, characterized in that when a "lean" lambda signal is present, only within the adaptation time (B, V) the adapted fuel quantity (1, 6) can additionally be adapted by a predeterminable increased correction quantity (4, 5), by means of a correction unit connected to the lambda sensor and the fuel quantity adaptation device, both in the event of an acceleration enrichment and in the event of a deceleration depletion.
2. Electronic engine control according to Claim 1, characterized in that the internal combustion engine is a naturally aspirated internal combustion engine.
3. Electronic engine control according to Claim 1 or Claim 2, characterized in that the electronic components of the fuel quantity adaptation device and/or the electronic components of the correction unit are integrated in an electronic engine control unit.
4. Electronic engine control according to one of Claims 1 to 3, characterized in that the lambda sensor is a two-point sensor with a digital output for a "lean" lambda signal and a "rich" lambda signal.
5. Electronic engine control according to Claim 4, characterized in that the increased correction quantity (4, 5), when the "lean" lambda signal is present, can be determined by multiplying the currently adapted fuel quantity (1, 6) by a factor of greater than 1.
6. Electronic engine control according to Claim 4 or Claim 5, characterized in that the increased correction quantity (4, 5), when the "lean" lambda signal is present, can be determined by adding together the adapted fuel quantity (1, 6) and a predeterminable correction amount in the style of a level shift.
7. Electronic engine control according to one of Claims 4 to 6, characterized in that the increased correction quantity (4, 5), when the "lean" lambda signal is present, can be determined by switching over to a stored correction characteristic diagram.
8. Electronic engine control according to one of Claims 1 to 3, characterized in that the lambda sensor has a continuous output as "lean" lambda signal corresponding to the current degree of "leanness" of the fuel-air mix, and in that the increased correction quantity, when the continuously variable "lean" sensor signal is present, can be determined by an associated, constant matching.
9. Electronic engine control according to one of Claims 1 to 8, characterized in that the adaptable fuel quantity (1, 6) and/or the adaptation time (B, V) and/or the increased correction quantity (4, 5) can be determined taking into account influencing variables, preferably temperature and degree of load change.
10. Electronic engine control according to one of Claims 1 to 9, characterized in that the adapted fuel quantity (1, 6) is determined by a relatively large short-term component (2), which is bell-shaped within a relatively short time, and a superimposed long-term component (3), which is shorter in relative terms and can be eliminated relatively slowly up until the end of the adaptation time (B, V), and in that the long-term component (3) can be influenced using the increased correction quantity (4, 5).

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