DE102008062668A1 - Active cylinder count changing method for internal combustion engine of vehicle, involves determining vehicle vibration level, and modifying active cylinder count based on vehicle vibration limit and vehicle vibration level - Google Patents

Abstract

The method involves determining a vehicle vibration limit based upon a vehicle speed (KPH) or a coolant temperature of an internal combustion engine (12). A vehicle vibration level is determined based on a number of active cylinders of the engine, a desired torque of the engine and a measured vibration level of a vehicle component e.g. seat track. An active cylinder count is modified based on the vehicle vibration limit and the vehicle vibration level. The vibration limit is increased by a correction factor based on a signal from a user actuated economy switch (38). An independent claim is also included for a control module comprising a vibration limit module.

Description

REFER TO RELATED APPLICATIONS

These Application claims the priority of US Provisional Application No. 61 / 018,956, filed on 4 January 2008. The disclosure of the above Registration is complete here incorporated by reference.

TERRITORY

The The present disclosure relates to the control of internal combustion engines and more particularly to systems and methods for controlling cylinder deactivation based on a component vibration level.

BACKGROUND

The Information in this section is only background information, which are related to the present disclosure, and do not need to form the state of the art.

combustion engines can in a full cylinder mode and cylinder deactivation mode be operable. In such engines can be in states with lower Load a number of cylinders to be disabled (no ignition). For example, an eight-cylinder engine may be in full-load mode Number of cylinders using all eight cylinders operable and in the cylinder deactivation mode using only four cylinders operable.

Of the Operation of the engine in the cylinder deactivation mode in states with low load can reduce the overall fuel consumption of the engine. In some cases however, the operation of the engine may be in the cylinder deactivation mode too unwanted Vehicle vibrations lead. The size of the vibration level stands with the torque of the engine (peak pressure of the cylinders) in relationship. If an oscillation frequency with a natural frequency a component matches and the size of the vibration big enough is to create a sympathetic vibration, the component can start to swing.

SUMMARY

One A method of modifying a number of active cylinders of an engine may be determining a vehicle vibration limit and a vehicle vibration level include. The number of active cylinders can be based on the vehicle vibration limit and the vehicle vibration level. In an example The vehicle vibration level may be based on the vehicle speed (KPH), on a number of active cylinders of the engine and on one Target torque of the engine based. The vehicle vibration limit can be based on the engine speed and a coolant temperature of the engine based.

One Control module can be a vibration limit module, a vibration level module and a cylinder transition module include. The vibration limit module may have a vibration limit based on the vehicle speed (KPH) and a coolant temperature of the motor. The vibration level module may have a vibration level based on a desired engine torque and / or the engine speed determine. The cylinder transition module may be a target number of active cylinders based on the vibration limit and the vibration level. On the basis of the provision For example, the control module may activate or deactivate cylinders of the engine. According to others Characteristics, the vibration modulus, the vibration limit on the Based on a signal from a user-operated economy switch determine.

Further Areas of application are clear from the description given here. Of course The description and the specific examples are for 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 Limit way.

1 FIG. 10 is a schematic diagram of a vehicle according to the present disclosure; FIG.

2 is a block diagram of a control module incorporated in 1 is shown; and

3A and 3B FIG. 10 is a control diagram illustrating steps for controlling the number of active cylinders according to the present disclosure. FIG.

PRECISE DESCRIPTION

The The following description is merely exemplary in nature and is intended to be the present disclosure, its application or uses do not limit. For the sake of clarity, in the drawings, the the same reference numerals used to designate similar elements. The term modulus as used herein refers to an application specific integrated circuit (ASIC), on a electronic circuit, on a processor (shared, dedicated or group) and to a memory, one or more Run software or firmware programs on a combinatorial Logic circuit or other suitable components that provide the desired functionality.

In 1 is an exemplary vehicle 10 shown schematically. The vehicle 10 can a motor 12 included with an intake system 14 , a fuel system 16 and an ignition system 18 communicated. The motor 12 Optionally, it may be operated in full cylinder mode and cylinder deactivation mode. The cylinder deactivation mode of the engine 12 In general, the operation of the engine 12 in which less than all cylinders are ignited include. For example, if the engine 12 eight cylinders 13 contains, the full-cylinder mode of operation includes the operation of the engine 12 in which all eight cylinders 13 be ignited while the cylinder deactivation mode of operation of the engine 12 includes, in which less than eight cylinders 13 ignited, about a four-cylinder operation of the engine 12 ,

The inlet system 14 can an intake manifold 20 and a throttle 22 include. The throttle 22 can make a flow of air into the engine 12 Taxes. The fuel system 16 can be a fuel flow in the engine 12 control and the ignition system 18 can the air / fuel mixture, that for the engine 12 through the inlet system 14 and the fuel system 16 is lit, ignite.

The vehicle 10 may further include a control module 24 and an electronic throttle control (ETC) 26 include. The control module 24 can with the engine 12 to monitor its speed and a number and duration of cylinder deactivation events. The control module 24 can also use the ETC 26 communicate to the airflow in the engine 12 to control. The ETC 26 can with the throttle 22 communicate and control their operation. A manifold absolute pressure sensor 28 and an air pressure sensor 30 can with the control module 24 communicate and can provide signals therefor that indicate a manifold absolute pressure (MAP) and an air pressure (P _BARO ), respectively. An engine coolant sensor 32 can with the control module 24 replace a signal indicating a motor temperature. A vehicle speed sensor 33 can signal with the control module 24 replace, which indicates the vehicle speed (KPH).

According to various embodiments, component accelerometers may be identified generally by the reference numeral 34 are designated with the control module 24 communicate and provide signals therefor that indicate component acceleration. The component accelerometer 34 may be accelerometers mounted on various components in the vehicle, such as a vehicle dashboard, a vehicle seat track, a steering column, and / or other components. In one example, the accelerometers 34 Measure the acceleration in real time and the signals indicating it with the control module 24 change. The accelerometer 34 can each be configured to exchange acceleration measurements in the direction of multiple axes (such as along the x, y, and z axes, etc.).

An economy switch 38 can with the control module 24 communicate and provide a signal. The economy switch 38 may be any switch that can communicate an "on" and "off" status. As described, the economy switch can 38 a user operated switch that allows increased acceptable vibration levels in the vehicle without the number of active cylinders of the engine 12 to modify. The economy switch 38 can be switched to the "ON" position to improve fuel economy. Obviously, the profitability switch 38 take other forms such as the shape of a button or another Vor be direction that can receive an operator input.

Now the control module 24 regarding 2 described in more detail. The control module 24 can be a vibration limit module 40 , a vibration level module 44 and a cylinder transition module 48 include. The vibration limit module 40 may be a vibration limit based on the vehicle speed (KPH) and / or a signal from the economy switch 38 and / or the coolant temperature.

According to a first implementation, the vibration level module 44 a vibration level based on a number of active cylinders (eg, the number of cylinders 13 that in the engine 12 ignited), the speed of the engine 12 and determine a desired torque. According to a second implementation, the vibration level module 44 a vibration level based on signals generated by the component accelerometers 34 be received, determine. Again, the component accelerometers can 34 be provided at desired locations in the vehicle such as on the vehicle seat rail, on the dashboard, on the steering column or anywhere else in the vehicle. Of course, the vibration level module 44 determine an oscillation level based on a combination of inputs from the first implementation and the second implementation. The cylinder transition module 48 can be the number of active cylinders of the engine 12 on the basis of the vibration limit and the vibration level.

With reference to the 3A and 3B becomes the control logic 100 for controlling the number of active cylinders of the engine 12 explained on the basis of a component vibration level. The control logic 100 can in step 102 begin in which the controller determines if the engine 12 is turned on. If the engine 12 works, takes the control in step 104 Counteract cylinder deactivation variables. The cylinder deactivation variables may include the engine speed (N _eng ), the actual engine torque (Tq _act ), the target engine torque (Tq _des ), the vehicle speed (KPH), the economy _switch state (SW _econ ), the specified number of cylinders (Cyl _del ), the intake air temperature (T _inlet ), the air pressure (P _baro ) and the engine _{coolant temperature} (T _coolant ). In step 106 The controller sets a number of activated cylinders to a specified number of cylinders.

In step 108 the controller determines the available torque under normal conditions (1 bar, 25 ° C). The available torque under normal conditions may be a function of activated cylinders and engine speed. The available torque under normal conditions can be represented as follows: Tq avail @ std = F (Cyl act , Neng) (1)

In step 110 The controller compensates for the available torque based on the atmospheric pressure provided by the air pressure sensor 30 is measured. The compensated torque can be represented by the following equation: Tq avail @ 25C = Tq avail @ std × (p baro / 101,3) (2)

In step 112 the controller compensates for the available torque based on an ambient temperature. The compensated torque can be represented by the following equation: Tq avail = Tq avail @ 25C × (298 / (T. inlet + 273)) (3)

In step 114 the controller determines if a desired torque is greater than the available torque. The determination can be represented as follows, where PTR is a percentage torque reserve. The PTR may be used to implement a buffer such that the available torque may be slightly greater than the desired torque. (Tq of × PTR)> Tq avail ? (4)

If a product of the target torque and the PTR is greater than the available torque, in step 116 the number of cylinders increases. Otherwise, in step 118 the number of cylinders is lowered.

In step 120 the controller determines the available torque under normal conditions (1 bar, 25 ° C). The available torque under normal conditions may be a function of activated cylinders and ei be ner engine speed. The available torque under normal conditions can be represented by the above equation (1).

In step 122 The controller compensates for the available torque based on the atmospheric pressure provided by the air pressure sensor 30 is measured. The compensated torque can be represented by the above equation (2).

In step 124 the controller compensates for the available torque based on an ambient temperature. The compensated torque can be represented by the above equation (3).

In step 126 The controller determines whether a target torque is greater than the available torque by using the above equation (4).

If the target torque is greater than the available torque, control determines in step 128 , whether the number of activated cylinders equals the maximum number of cylinders in the engine 12 is. If the number of activated cylinders is equal to the maximum number of cylinders, the control becomes the step 146 directed. If the number of activated cylinders is not equal to the maximum number of cylinders, the control becomes the step 116 directed. If in step 126 the target torque is not greater than the available torque determines the controller in step 130 a vehicle vibration limit. The vehicle vibration limit may be a function of vehicle speed (KPH). The vehicle vibration limit can be represented as follows: V lim = F (KPH) (5)

In step 132 the controller determines if the economy switch 38 is in the "ON" or active position. If the economy switch 38 active, corrects the control in step 134 the economic viability limit. The corrected vibration limit can be represented by the following equation, in which EVM is a calibration variable: V lim = V lim × EVM (6)

As has been described above, when the economy switch 38 is active, the oscillation limit is increased by a correction factor (F _economy ). The F _economy factor can be calibrated to meet any allowable vibration limit. The corrected vibration limit can be represented by the following equation: V lim = V lim × F economy (7)

In certain cases, a vehicle operator may desire to tolerate increased vibration to achieve fuel economy. By increasing a tolerance of the vibration limit (active economy switch 38 ), the controller can control the operation of the engine 12 continue with a reduced number of active cylinders and thus increase fuel economy.

In step 136 the controller compensates for the vibration limit based on a coolant temperature of the engine 12 , The compensated vibration limit can be represented by the following equation: V lim = V lim × (F (t coolant )) (8th)

In step 138 the controller determines a vibration level. In one example, the controller may implement open-loop control to determine a vibration level. In an open loop controller, the vibration level may be determined as a function of engine speed, engine torque, and a number of active cylinders. The vibration level can therefore be determined from a four-dimensional look-up table. The vibration level can be represented as follows: V lev = F (Cyl act , N closely , Tq of ) (9)

In one example, a vibration map may be by attaching accelerometers 34 on individual passenger compartment components (steering column, driver seat rail, dashboard, etc.) and through Operating the vehicle in such a way that the engine 12 a full speed range and a full motor torque range, are generated. The cylinders 13 are locked in a particular state (eg, five-cylinder state for an eight-cylinder engine), and a unique vibration map can be generated for each active cylinder state. From the outputs of all accelerometers 34 A weighted RMS average vibration (explained later) can be calculated. For each number of cylinders an "xyz" scatter plot can be generated. The scatter plots may be used to generate a three-dimensional table in which the component vibration is a function of engine speed and engine torque. In one such example, the accelerometers become 34 used only during testing to generate the four-dimensional lookup tables for each active cylinder state.

As another example, the controller may implement a closed-loop control to determine a vibration level. In closed-loop control, the controller can provide a real-time vibration level based on the signals from the accelerometers 34 determine. As has been described, the component accelerometers can 34 be provided at desired locations in the vehicle such as on the vehicle seat rail, on the dashboard, on the steering column or anywhere else in the vehicle. In closed-loop control, some or all of the accelerometers can 34 be provided in the vehicle to real-time vibration level with the control module 24 exchange. The accelerometer 34 can provide accelerations in multiple directions (x, y, z, etc.).

In one implementation, accelerometer signals from one or more components are weighted differently than accelerometer signals from other components. The weighting of the accelerometer signals can be used for both the open loop examples described above and the closed loop examples described above. It can be appreciated that it could be more important to quantify and respond to a vibration level of one component (such as a vehicle seat track) as compared to another component (such as a vehicle dashboard). A weighted effective or RMS component vibration can be represented by the following equation, where ST = driver seat rail; CA = handlebar arm of a non-driven wheel for compensation of the road surface, acceleration and cornering; SC = steering column; D = dashboard; x = longitudinal direction; y = transverse direction; z = vertical direction; a, b, c ... = weighting factors; T = a + b + c ...

In step 140 the controller determines whether the vibration level is greater than the vibration limit by using the following expression in which VO represents a hysteresis constant. VO (Vibration Offset) is a buffer to reduce the control system load that would occur if level and limit were nearly equal. The determination can be represented as follows: V lev > V lim + VO? (10)

If the vibration level is not greater than the vibration limit, the control becomes the step 146 directed. If the vibration level is greater than the vibration limit, the controller increases the number of cylinders in the step 142 , In step 144 Control determines whether the number of activated cylinders equals the maximum number of cylinders in the engine 12 is. If the number of activated cylinders is equal to the maximum number of cylinders, the control becomes the step 146 directed.

If the number of activated cylinders is not equal to the maximum number of cylinders, the control becomes the step 138 directed. In step 146 the controller sets the specified number of cylinders to the number of active cylinders. The controller then becomes the step 102 directed.

Those skilled in the art will now appreciate from the foregoing description that the broad teachings of the present disclosure can be implemented in many different forms. Therefore, while the disclosure has been described in conjunction with specific examples thereof, the true scope of the disclosure should not be so limited since other modifications will become apparent to the skilled practitioner upon a study of the drawings, the specification, and the following claims the.

Claims (19)

Method, comprising: Determine a Vehicle vibration limit based on vehicle speed (KPH) and / or a coolant temperature of the motor; Determining a vehicle vibration level; and Modify a number of active cylinders based on the vehicle vibration limit and vehicle vibration level. The method of claim 1, wherein determining the Vehicle vibration level also on a number of active cylinder of the engine and / or a desired torque of the engine based. The method of claim 1, wherein determining the Vehicle vibration level at a measured vibration level a vehicle component based. The method of claim 3, wherein the vehicle component at least one vehicle component comprising, from a group selected from vehicle components is that a steering column, a seat rail and a dashboard includes. The method of claim 4, wherein the vehicle vibration level based on at least two of the vehicle components, wherein a vibration level one of the vehicle components has a first weight and a Vibration level of another of the driving compo- nents a second Weighting, with the first weighting of the second weighting is different. The method of claim 5, wherein the vehicle vibration level the seat rail has the first weight and the vehicle vibration level the steering column and / or the dashboard has the second weighting, wherein the first weighting higher than the second weighting is. The method of claim 1, wherein determining the Vehicle vibration limit on a signal from one by one User pressed Economy switch based, the vibration limit on the basis of the signal is increased by a correction factor. Control module comprising: a vibration limit module, a vibration limit based on a measured vehicle speed (KPH) and / or a coolant temperature an engine determined; a vibration level module that has a Vibration level based on a target engine torque and / or the speed of the engine determines; and a cylinder transition module, the one set number of activated cylinders based on the vibration limit and the vibration level determined. Control module according to claim 8, wherein the vibration limit module Further, the vibration limit based on an input from one operated by a user Profitability switch determined. Control module according to claim 8, wherein the vibration level module the vibration level based on both the desired engine torque and the speed of the engine and further based on a Number of active cylinders of the engine determined. Control module according to claim 8, wherein the cylinder transition module a cylinder based on the target number of activated cylinders of the motor is activated or deactivated. Control module comprising: a vibration limit module, a vibration limit based on a measured vehicle speed (KPH) and / or a coolant temperature an engine determined; a vibration level module that has a Vibration level based on a measured vibration level a vehicle component determined; and a cylinder transition module, the one set number of activated cylinders based on the vibration limit and the vibration level determined. The control module of claim 12, wherein the vibration limit module Further, the vibration limit based on an input from one operated by a user Profitability switch determined. The control module of claim 12, wherein the vehicle component a steering column includes. The control module of claim 12, wherein the vehicle component includes a seat rail. The control module of claim 12, wherein the vehicle component includes a dashboard. The control module of claim 12, wherein the vehicle component at least two of the following elements comprises: steering column, seat rail and dashboard. The control module of claim 12, wherein the cylinder transition module a cylinder based on the target number of activated cylinders of the motor is activated or deactivated. The control module of claim 12, wherein the vibration level module the vibration level based on at least two of the vehicle components determined, wherein a vibration level of one of the vehicle components has a first weight and a vibration level one more the vehicle components has a second weighting, the first Weighting is different from the second weighting.