DE102008039571A1 - Idle speed control system for internal combustion engine, has spark timing module regulating idle speed of engine including adjustment of spark timing for cylinders individually based on period differences - Google Patents

Abstract

The system (10) has a piston reciprocation module determining reciprocation periods of piston of cylinders (20) of an engine (12) based on engine speed signal. A difference module determines a period difference between the reciprocation periods and an idle period associated with a target idle speed. A spark timing module regulates idle speed of the engine including adjustment of spark timing for the cylinders individually based on the period differences. An average reciprocation module calculates an average reciprocation period based on the period differences. Independent claims are also included for the following: (1) a method for regulating an idle speed of an engine (2) a method for generating a common torque from each cylinder of an engine.

Description

TERRITORY

The The present disclosure relates to engine control and in particular to the torque output during engine idle periods.

BACKGROUND

The Statements in this section provide only background information in terms of The present disclosure and not necessarily the state the technology.

One Internal combustion engine of a vehicle generated by the combustion an air / fuel mixture, a drive torque. The air gets closer sucked into the engine and mixed with fuel. The air / fuel mixture is in a Cylinder of the engine compressed and ignited. The combustion of the compressed Air / fuel mixture drives a reciprocating Piston in the cylinder. The piston in turn drives a crankshaft rotatory, which outputs a drive torque to a drive train.

In some cases, for example, when the vehicle is stopped, the engine is running at or near at idle speed at idle. Fluctuations in idle speed can Cause vibrations. The fluctuations are due to torque output differences caused between the respective cylinders of the engine. The differences in the torque output can with several factors such as an effective compression ratio, one Air / fuel ratio etc. are related. The torque output differences between the cylinders increase with increasing age of the engine.

One A method for controlling the engine idling speed of the engine comprises adjusting the air and / or fuel flow to a chosen one Maintain idling speed. This has only a limited Control over maintaining idle speed and preventing of fluctuations in the torque output.

SUMMARY

In an embodiment An idle speed control system for an engine is provided which an engine speed module that generates an engine speed signal. A piston reciprocation module determines based on the engine speed signal Reciprocating periods of all pistons of cylinders of the engine. A difference module determines a period difference between each the reciprocation periods and a target idle speed allocated idle period. An ignition timing module regulates one Idle speed of the engine, which is the individual setting of the ignition timing for each the cylinder comprises based on period differences.

According to others Features includes a method for regulating idle speed an engine generating an engine speed signal. For all pistons the engine's cylinders are based on the engine speed signal Reciprocation periods determined. It will be a period difference between each of the reciprocal periods and one of a target idle speed assigned idle period determined. The idle speed is which regulates the individual setting of the ignition timing of each of the cylinders based on the period differences.

Again Further features include a method for generating a common Torque of all cylinders of a motor generating a Engine speed signal. For all pistons of the cylinders of the engine are based on the engine speed signal Reciprocation periods determined. It will be a period difference between each of the reciprocal periods and one of a target idle speed assigned idle period determined. The respective torque outputs the cylinders are stacked on the basis of the period differences tuned while the engine is operating at idling speed.

According to one another feature is regulation, which involves stepping the ignition timing.

According to one another feature is that regulation involves either advancing or delaying the ignition timing.

According to one further feature, the method further comprises regulating the ignition timing, determining if the engine is stable and further regulating the ignition timing, when the engine is working stably.

According to one Another feature is regulating when the engine is idling stable working.

According to one yet another feature Zündzeitpunkteinstellwerte be generated. The spark timing values are saved. On working the engine at an idling speed will the ignition of the engine based on the spark timing values initiated.

Further fields of application will be apparent from the description given here. Even of course, the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

DRAWINGS

The Drawings described herein are for illustration only and are not intended to limit the scope of the present disclosure in any way.

1 FIG. 10 is a functional block diagram of an exemplary idle speed control system according to an embodiment of the present disclosure; FIG.

2 FIG. 10 is a logical flowchart showing a method of controlling the idle speed of a motor according to an embodiment of the present disclosure; FIG. and

3 FIG. 12 is a functional block diagram of exemplary modules that perform engine idling control in accordance with an embodiment of the present disclosure.

PRECISE DESCRIPTION

One A method for controlling an idle speed of an engine comprises the adjustment of the air flow and the adjustment of the ignition timing of engine cylinders. The air flow to the engine is set, to set a current idle speed to coincide with a selected idle speed. Variations of the set idle speed of the engine will be adjusted by adjusting or adjusting the ignition timing. The ignition timing is executed dynamically. By delaying the ignition timing will be a value for the maximum spark in favor of the best torque (maximum spark for best torque, MBT) reduced. The more the MBT value is reduced, the larger one is Influence area available is. This area is called the torque reserve. As a smaller one Torque output is effected when an engine speed underrun An increase in pre-ignition causes an increase in torque. An increase in torque increases the speed of the motor and thereby corrects the shortfall.

The stated idle speed control is by a control loop, at the selected idle speed based, created. When the control is active, it will be on all Cylinder same pre-ignition correction applied in the same way during each cyclically recurring Event. The creates a limited control over the Torque output of each of the cylinders and thus a limited ability for preventing idling fluctuations. The explained control affects the idle speed, but does not correct the difference in torque from each cylinder. The following disclosed Create embodiments an improved control over the torque output of each of the cylinders and the improved idle speed performance.

The The following description of the preferred embodiment is in essence merely by way of example and not intended to embody the invention, restrict their use or their uses. For the sake of clarity in the drawings, the same reference numerals for indicating similar Elements used. The term module, as used here, refers to an application specific integrated circuit (ASIC), an electronic circuit, a processor (shared, specially assigned or for one Group) and a memory containing one or more software or Run firmware programs, one combinational logic circuit or other suitable components, which provide the described functionality.

In 1 is an exemplary engine idling control system 10 shown. The engine idling control system 10 includes a motor 12 , an intake manifold (IM) 14 and an exhaust manifold (EM) 16 , Through a throttle 18 Air gets into the intake manifold 14 sucked and to cylinder 20 distributed. The air is mixed with fuel, with the air / fuel mixture in the cylinders 20 compressed and ignited. This drives pistons that are in the respective cylinders 20 to move back and fourth. The engine idling control system 10 further includes an ignition system 21 with spark plugs 22 that the cylinders 20 each associated with and cause combustion events therein. The reciprocating pistons drive a crankshaft 24 rotationally. Exhaust gases are from the cylinders 20 through the exhaust manifold 16 pushed out.

An idle speed control module 30 regulates the operation of the engine system 10 based on the engine idle speed control of the present disclosure. An engine speed indicator sensor 32 generates an engine speed indication signal. The engine speed sensor 32 may include a crankshaft position sensor and based on the rotational position of the crankshaft 24 generate a crankshaft position signal. The engine speed sensor 32 may include a camshaft sensor, a transmission sensor, etc. Furthermore, the control module determines 30 the engine speed and the position of all pistons in the respective cylinders based on the engine speed show signal.

The motor 12 operates using a four-stroke combustion cycle. During an intake stroke, a piston of the engine moves 12 from a top dead center (TDC) position in each cylinder down to a bottom dead center (UT) position, drawing the air / fuel mixture (ie, intake stroke). After the piston reaches the UT position, it moves up the cylinder to compress the air / fuel mixture (ie, compression stroke). When the piston is in and near TDC, an associated spark plug ignites the air / fuel mixture. The combustion of the air / fuel mixture pushes the piston back toward the UT position (ie power stroke) to the crankshaft 24 drive. After the combustion event, the piston moves back up toward the TDC position, pushing exhaust gases into the exhaust manifold (ie, exhaust stroke).

Of the ignition timing refers to the time at which a spark plug is an air / fuel mixture ignites and is based on the position of a piston in a cylinder. The Position of the piston can be in the form of the rotational position of the crankshaft to be delivered. For example, the ignition timing of a particular Cylinder as X ° in front OT to be delivered. Thus, the ignition occurs when the crankshaft at X °, before the piston reaches TDC in the cylinder. The ignition point for every cylinder can respect a respective current ignition timing position delayed or brought forward.

The engine idle control described with respect to the embodiments disclosed herein regulates the torque output of each cylinder by adjusting the ignition timing of each cylinder on an individual basis. The engine idle control applies the spark timing to each cylinder. More specifically, engine idle speed control monitors the reciprocal period (t _RECi ) of each piston per combustion cycle as an indication of torque, where i is the piston / cylinder number. The piston / cylinder number i may vary according to the firing order of the spark plugs 22 increase. The reciprocal period t _RECi is determined according to the following relationship: t řeči = 1 / RPM i where RPM _{i is} the engine speed during the combustion cycle of the cylinder i. The shorter the reciprocal period t _RECi , the greater the torque output of a cylinder.

The control module 30 determines period differences Δt _i based on the following relationship: .delta.t i = t řeči - t IDLE where t _{IDLE is} the period associated with a target engine idle RPM _IDLE . The engine idle control compares the period differences Δt _i for each of the cylinders in conjunction with a current engine speed and calculates a mean reciprocal period Δt _AVG . In one embodiment, the average reciprocal period Δt _{AVG is associated} with each combustion cycle of the cylinders. In another embodiment, the average reciprocal period Δt _{AVG is associated} with a plurality of combustion cycles of the cylinders, respectively. The control module 30 _By means of a control based on the reciprocal periods t _RECi, the ignition timing is set for each of the cylinders 20 individually adjusted to match the mean reciprocal period Δt _AVG . The mean reciprocal period Δt _AVG is determined according to the following relationship: .delta.t AVG = (Δt 1 + Δt 2 + ... Δt i ) / I

Each of the period differences Δt _i may represent a period difference average for a piston over one or more combustion cycles.

The ignition timing is set based on the time differences Δt ₁ and the mean reciprocal period Δt _AVG . Ignition timing set values are determined based on the difference between the period differences Δt _i and the mean reciprocal period Δt _AVG . The spark timing values may be stored in memory 34 stored and / or used to change the ignition timing of the individual cylinders. The ignition timing of each cylinder can be adjusted step by step. For example, the ignition timing can be set in one or more 1 ° increments. The phasing of the spark timing allows the engine idle speed control to determine if the spark timing is properly adjusted (ie, properly advanced or retarded). For example, the engine idle speed control may adjust the ignition timing, wait for the engine to run in a stable mode after adjustment, re-evaluate updated piston reciprocal periods, and then, if appropriate, reestablish spark timing.

The stable mode of operation of an engine may be associated with the engine idling for a predetermined period of time at a nearly constant speed. The stable mode of operation may be additionally or alternatively associated with that of each piston of an engine for a given period of time, a constant operating speed, and / or an associated reciprocation period has.

Engine idle speed control is adaptive in that it estimates the spark timing values for each of the cylinders 20 learns and always adjusts the ignition timing when the conditions of the engine 12 how about how to change as a result of aging. By setting the period per cylinder per combustion cycle to the same value for all cylinders, torque output fluctuations of the engine become 12 eliminated, because all cylinders deliver the same torque at this operating point. Deviations from the selected idle speed can be corrected using the techniques described herein. The techniques provided by the embodiments of the present disclosure minimize and / or eliminate torque fluctuations of an engine.

In 2 For example, a logic flowchart illustrating a method of controlling the idling speed of an engine is shown. The method may include multiple adjustment cycles. In other words, the following steps can be repeated. In step 200 the controller determines if the engine is operating at idle speed. If the engine is not idling, the controller loops back and repeats the step 200 , When the engine is idling, the controller continues to perform the steps 202 - 218 continued. The steps 202 - 214 are performed while the engine is operating at near idle speed. In step 202 the controller sets a counter i to 1. The counter i indicates the i-th piston and / or cylinder, which in step 202 can be counted up according to the firing order of the cylinders of the engine.

In step 204 the controller monitors the engine speed (RPM) based on a generated engine speed signal. In step 206 the controller calculates the reciprocal periods t _RECi . The controller calculates in step 208 the period differences Δt _i .

In step 210 the controller determines if i equals N plus 1, where N is the number of pistons and / or cylinders of the engine. If i is not equal to N + 1, control i increments in step 212 and returns to the step in a loop 204 back. If i is equal to N + 1, Δt has been determined for all cylinders, with control at step 214 continues. In step 214 the controller determines the mean reciprocal period Δt _AVG .

In step 215 the controller determines if the engine is operating at idle speed. If the controller is operating at idle speed, control goes to step 217 further; otherwise the controller will go to the step 216 further. In step 216 the controller stores the ignition timing signals.

In step 217 the controller sets the ignition timing of the individual cylinders based on the ignition timing control signals.

In step 218 the controller determines whether the engine is in a steady state, as described above. When the engine is in a steady state, control may go to step 200 to return.

Regarding 3 Now, exemplary modules that perform the engine idle speed control of the present disclosure will be described in detail. The exemplary modules include an RPM monitoring module 300 , a piston reciprocation module 302 , a target idle module 304 , a difference module 306 , a module for medium reciprocation 308 and an ignition timing module 310 , The engine speed module 300 monitors the speed of a motor, which can be expressed in revolutions per minute (RPM). The engine speed module 300 generates a speed signal based on the output of the crankshaft position sensor. The piston reciprocation module 302 determines the reciprocation periods t _RECi for all cylinders of the engine based on the speed of the motor.

The target idle module 304 determined based on the idle speed RPM _IDLE the target idle period t _IDLE. The difference module 306 calculates the period differences Δt _i for the cylinders based on the respective piston _{reciprocal period} t _RECi and the target idle period t _IDLE . The module for medium reciprocation 308 determines the average reciprocal period Δt _AVG based on the respective period differences Δt _i for the cylinders.

The ignition timing module 310 On the basis of the differences between the period differences Δt _i and the mean reciprocal period Δt _AVG, the ignition timing is adjusted to provide a balanced cylinder torque. The ignition timing module 310 sets the ignition timing based on a steady state signal 311 from a stable state module 312 one. The stable state module 312 determines whether the engine is based on an engine speed signal and / or on piston speed indication signals such as signals based on the piston _{reciprocation} signals t _RECi 12 works in a stable mode.

As an example, the spark timing module 310 Compare a first period difference .DELTA.t ₁ with a mean reciprocal period .DELTA.t _AVG and set the ignition timing of a first cylinder, which is the updating of a first period difference .DELTA.t ₁ for a subsequent combustion cycle and the tuning of this with the mittle reziprokationsperiode .DELTA.t _AVG includes. The ignition timing of a first spark plug of the first cylinder is advanced or retarded. The ignition timing module 310 may then compare a second period difference Δt ₂ with the mean reciprocal period Δt _AVG and set the ignition timing of a second cylinder, which includes updating a second period difference Δt ₂ for a subsequent combustion cycle and adjusting it with the mean reciprocal period Δt _AVG . The ignition timing of a second spark plug of the second cylinder is advanced or retarded. The setting of the spark timing for the second spark plug may be the same as or different from the spark timing for the first spark plug. When setting the ignition timing, the ignition timing of one or more of the cylinders of the engine 12 remain unchanged.

professionals can From the above description, realize that the far-reaching doctrines The present disclosure is implemented in various forms could be. Therefore, although the embodiments disclosed herein are intended to be in connection with specific examples of them have been described, the true ones Scope of the embodiments not be limited to this as the experienced practitioner after studying of the drawings, the specification and the following claims amendments become apparent.

Claims (20)

Idle speed control system for one Motor comprising: an engine speed module that is an engine speed signal generated; a Kolbenreziprokationsmodul based on the engine speed signal Determined reciprocation periods of all pistons of the cylinders of the engine; one Difference module, which is a period difference between each of the reciprocation periods and an idle period associated with a target idle speed certainly; and an ignition timing module, which regulates an idle speed of the engine, which is the individual Adjusting the ignition timing for each the cylinder comprises based on the period differences. An idling speed control system according to claim 1, which furthermore a module for average reciprocation includes, based on the period differences calculated mean reciprocal period, wherein the ignition timing module based on the average period of reciprocation, the ignition timing each of the cylinders adjusts. An idling speed control system according to claim 2, wherein the ignition timing module comparing a first period difference with the mean reciprocal period and the ignition timing of a first cylinder, which means updating another first Period difference and tuning of this with the middle one Includes reciprocation period, and wherein the ignition timing module is a second Period difference compared with the mean reciprocal period and the ignition time of a second cylinder, which makes updating another second period difference and tuning this with the middle one Includes reciprocation period. Engine idling speed control system according to claim 1, wherein the ignition timing module the ignition timing for each the cylinder is adjusted step by step. Engine idle speed control system according to claim 4, wherein the ignition timing module while each Setting cycle the ignition timing Gradually adjusted by a single degree. Engine idling speed control system according to claim 1, wherein the ignition timing module when setting the ignition timing the ignition timing for each the cylinder advanced or delayed. Engine idling speed control system according to claim 1, wherein the ignition timing module the ignition timing for each the cylinder sets differently. Engine idling speed control system according to claim 1, further comprising a stable state module that is a stable state signal indicating the state of the engine, the ignition timing module the ignition timing on the basis of the stable state signal. Engine idling speed control system according to claim 1, wherein the ignition timing module the ignition timing each of the cylinders adjusts when the engine is at idle speed is working. Engine idling speed control system according to claim 9, wherein the ignition timing module the adjustment of the ignition timing prevented when the engine is operating at speeds that are determined by the Idling speed are different. A method of regulating an idle speed of an engine, comprising: generating an engine speed signal; Determining reciprocation periods of all pistons of the cylinders of the engine based on the engine speed signal; Determining a period difference between each of the reciprocal periods and an idle period associated with a target idle speed; and regulating the idling speed, which is the individual setting of the ignition timing for each of the cylinders which comprises on the basis of the period differences. The method of claim 11, wherein said regulating the idle speed includes: Calculating a mean reciprocal period based on the period differences; and Adjusting the ignition timing each of the cylinders based on the mean reciprocal period. The method of claim 11, wherein said regulating the idle speed, the different setting of the ignition timing for each the cylinder comprises. The method of claim 11, further comprising: to save the setting values for the ignition timing; and Initiate the ignition of the engine based on the set values when the engine returns to working at idle speed. Method for generating a common torque of all the cylinders of an engine, which includes: Generating a Engine speed signal; Determining reciprocal periods all pistons of the cylinders of the engine based on the engine speed signal; Determine a period difference between each of the reciprocal periods and an idle period associated with a target idle speed; and Tuning of the respective torque outputs of the cylinders relative to each other based on the period differences, during the Engine is operating at an idle speed. The method of claim 15, wherein said tuning the torque output, the individual setting of the ignition timing for each the cylinder comprises based on the period differences. The method of claim 15, wherein said tuning the torque output includes: Calculating a mean reciprocal period based on the period differences; and Adjusting the ignition timing each of the cylinders based on the mean reciprocal period. The method of claim 17, comprising: to compare a first period difference with the mean reciprocal period and adjusting the ignition timing a first cylinder, which is the updating of another first Period difference and tuning of this with the middle one Period difference includes; and Comparing a second period difference with the mean reciprocal period and setting the ignition timing a second cylinder, which is the updating of another second Period difference and tuning of this with the middle one Includes reciprocation period. The method of claim 15, wherein said tuning the torque output, the stepwise adjustment of the ignition timing for each the cylinder comprises. The method of claim 15, wherein said tuning the torque output the different setting of the ignition timing for each the cylinder comprises.