DE102020204298A1 - PROCEDURE FOR CONFIRMING A VALVE PHASE WHEN STARTING AN INTERNAL COMBUSTION ENGINE AND VEHICLE OPERATION CONTROL - Google Patents

Abstract

The present invention can promptly confirm a valve phase in starting an internal combustion engine. An engine ECU 51 shifts the valve phase to the most retarded position by an electrically powered VVT system when the engine 5 is started, successively determines whether an absolute value of valve phase deviation, that is, a difference between outputs of a cam angle sensor 3 to a consecutive one Time below a specified reference deviation determines that the valve phase has reached the most retarded position in the case where the absolute value of the valve phase deviation is below the reference deviation, and uses the confirmed valve phase for starting control for the engine 5.

Description

Technical area

The present invention relates to a method of confirming a valve phase when starting an internal combustion engine and to vehicle operation control, and more particularly, to improving a starting characteristic of the internal combustion engine and the like.

Background of the invention

It is well known that a variable valve timing system (hereinafter referred to as “VVT”) is used in an automobile in order to improve fuel economy of an internal combustion engine, driving performance, and the like. The VVT system can set a valve phase, i.e. a valve position, when the valve is opened / closed.

Two types of such VVT systems are available, which are a hydraulic drive VVT system configured to adjust the valve phase by hydraulic pressure and an electric drive VVT system configured to adjust the valve phase using an electric motor .

Compared with the hydraulic drive VVT system, the electric drive VVT system has such an advantage that a restriction range is limited under an environmental condition such as temperature, and the electric drive VVT system is therefore in a wide range can be used.

With regard to the VVT system with hydraulic drive, however, due to a structure thereof, the valve phase returns to an initial position after an engine shutdown. Thus, by adding a locking mechanism, the initial position can be maintained until the engine is restarted and the engine can be restarted without any problems.

A structure of the electric drive VVT system is different from the structure of the hydraulic drive VVT system described above. The electric drive VVT system is not structured so that the valve phase is returned to the original position after the engine stop, and because of the structure thereof, it is difficult to provide the electric drive VVT system with the lock mechanism. Thus, it is normal that the electric drive VVT system is structured so as not to have the lock mechanism.

For this reason, if the vehicle is switched off (ignition switched off) and an external force is applied to the vehicle, the valve phase may be changed from the valve phase at the time of the system shutdown.

If an ignition switch is switched on after the system has been shut down, the valve phase can consequently differ from the valve phase when the system was last shut down and a phase shift must be detected. Otherwise, misfire or abnormal combustion may result.

Therefore, it is imperative for the vehicle using the electric drive VVT system to know the valve phase when an engine is started.

Generally, when starting the engine, it is necessary to know a cylinder position and a valve position when starting. A method of determining the cylinder of the engine and calculating the valve phase using a crank angle detected by a crank angle sensor and a cam angle detected by a cam angle sensor and the like are thus conventionally known (see, for example, Japanese Patent Laid-Open No. 2003- 056381). However, such methods have the following problems.

In the method of determining the cylinder of the engine using the crank angle detected by the crank angle sensor and the cam angle detected by the cam angle sensor, a speed for determining the cylinder depends on a rotation frequency of a starter. For example, the rotation frequency of the starter is decreased under a low temperature environment due to a decrease in a battery voltage. As a result, there arises such a problem that a time required for determining the cylinder becomes longer from a normal time and an engine starting time becomes longer from that at a temperature close to a normal temperature.

In addition, with this method, the valve phase is not obtained until the determination on the cylinder is completed. As a result, the valve phase cannot be changed while the cylinder is being determined. For this reason, it is also difficult to shorten the engine starting time.

The present invention has been made in view of the above, and therefore provides Method for confirming a valve phase when starting an internal combustion engine and a vehicle operating control which is capable of immediately confirming the valve phase when starting the internal combustion engine.

Disclosure of the invention

In order to achieve the above purpose of the present invention, a method of confirming a valve phase upon starting an internal combustion engine is according to the present invention

• Verschieben der Ventilphase zu einer am meisten verzögerten Position durch das System mit variablen Ventilsteuerzeiten beim Anlassen der Verbrennungskraftmaschine; sukzessives Bestimmen, ob eine Ventilphasenabweichung, das heißt eine Differenz zwischen Ausgabewerten eines Nockenwinkelsensors zu einer konsekutiven Zeit, unter einer spezifizierten Bezugsabweichung liegt; Bestätigen der Ventilphase, dass die Ventilphase die am meisten verzögerte Position erreicht hat, in dem Fall, in dem die Ventilphasenabweichung unter der Bezugsabweichung liegt; und Verwenden der Ventilphase zur Anlasssteuerung für die Verbrennungskraftmaschine.

a method for confirming a valve phase in an internal combustion engine start that confirms a valve phase in an internal combustion engine having a variable valve timing system configured to adjust the valve phase of the internal combustion engine, the method comprising:

• Shifting the valve phase to a most retarded position by the variable valve timing system upon starting the internal combustion engine; successively determining whether a valve phase deviation, that is, a difference between output values of a cam angle sensor at a consecutive time, is below a specified reference deviation; Confirming the valve phase that the valve phase has reached the most retarded position in the case where the valve phase deviation is below the reference deviation; and using the valve phase for starting control for the internal combustion engine.

In order to achieve the above-mentioned purpose of the present invention, there is also a vehicle operation controller according to the present invention
a vehicle operation controller configured to perform operation control for an internal combustion engine using an electronic control unit, and the internal combustion engine includes a variable valve timing system configured to adjust the valve phase of the internal combustion engine.

The electronic control unit is configured to: shift the valve phase to a most retarded position by the variable valve timing system upon engine start; successively determining whether a valve phase deviation, that is, a difference between output values of a cam angle sensor at a consecutive time, is below a specified reference deviation; Confirming the valve phase that the valve phase has reached the most retarded position in the case where the valve phase deviation is below the reference deviation; and using the valve phase for starting control for the internal combustion engine.

According to the present invention, the valve phase with the most retarded position as a target is forcibly changed and it is determined that the valve phase has reached the most retarded position as an end point when the change in the output value of the cam angle sensor is equal to or less than the specified value than becomes the same. In this way, the valve phase can be confirmed immediately when starting. Accordingly, compared with the case where the valve phase is confirmed by a conventional cylinder determination, such effects can be employed that the valve phase at the start can be confirmed promptly with a high degree of possibility that the starting time of the internal combustion engine can be shortened, and that reliability of starting the same can be improved.

Figure list

• 1 Fig. 13 is a configuration view illustrating a configuration example of a vehicle operation controller in an embodiment of the present invention.
• 2 Fig. 13 is a configuration view illustrating a system configuration example of an electrical system for executing processing for valve phase confirmation upon start-up of an internal combustion engine by the vehicle operation controller according to the embodiment of the present invention.
• 3 Fig. 13 is a flowchart of a subroutine for illustrating an operation of the processing for valve phase confirmation at the time of starting the internal combustion engine, which is executed by the vehicle operation control according to the embodiment of the present invention.
• 4th includes graphs schematically illustrating state changes of main portions at the time when the processing for valve phase confirmation is executed in starting the internal combustion engine according to the embodiment of the present invention, wherein 4A is a schematic graph for illustrating presence or absence of supply of a power supply voltage, 4B a schematic graph illustrating changes in a target phase angle of a valve and an actual phase angle of the valve, which are determined by a VVT system with electric drive, 4C is a schematic graph to illustrate a point in time at which an endpoint determination takes place, 4D is a schematic graph illustrating a starting point of tempering, 4E Figure 13 is a schematic graph for illustrating a change in engine speed; 4F FIG. 13 is a schematic graph for illustrating a completion timing of determining a cylinder, and FIG 4G Figure 13 is a schematic graph illustrating an ignition start point.

Description of the specific embodiment

The following is a description of an embodiment of the present invention with reference to FIG 1 to 4th respectively.

Note that members, an arrangement, and the like described below do not limit the present invention, and various modifications can be made thereto within the scope of the spirit of the present invention.

First, a description will be given of a configuration example of a vehicle operation control to which a method of confirming a valve phase in starting an internal combustion engine according to the embodiment of the present invention is applied with reference to FIG 1 and 2 respectively.

The vehicle operation control according to the embodiment of the present invention is particularly suitable for valve phase control by an electric drive VVT system (detailed description will be given later).

More specifically, the vehicle operation controller according to the embodiment of the present invention is configured to include, as main components, an engine ECU (as “E-ECU” in FIG 1 described) 51 using an electronic control unit, a VVT system 1 with electric drive, a crank angle sensor 2 , a cam angle sensor 3 and a rotation frequency sensor 4th of a VVT motor with electric drive.

Similar to the related art is the engine ECU 51 configured to perform various types of control required for travel control of a vehicle, and examples of such control are speed control and control of fuel injection for an engine 5 such as the internal combustion engine.

Such an engine ECU 51 is configured to include, for example, as main components: a microcomputer having a known / well-known configuration as a central component; a storage element (not illustrated) such as random access memory (RAM) or read only memory (ROM); and an input / output interface circuit (not illustrated).

This engine ECU 51 receives detection signals from the crank angle sensor 2 , the cam angle sensor 3 and the rotation frequency sensor 4th of an electric drive VVT engine, and various signals such as an accelerator pedal position and a vehicle speed which are detected by unillustrated sensors or the like and which are required for vehicle operation control. The various signals sent by the engine ECU 51 are received, in addition to the engine speed control and the fuel injection control, are also used for processing for valve phase confirmation at engine cranking according to the embodiment of the present invention, which will be described later, and the like.

The VVT system 1 with electric drive is a system with variable valve timing. This VVT system 1 with electric drive is specifically configured to control the valve phase by a VVT actuator 1a with electric drive (see 2 ) can be set using a motor, and a basic configuration of the same is similar to the conventional VVT system with electric drive.

It is assumed that a VVT system 1 with an electric drive on at least one inlet valve (not illustrated) and / or one outlet valve (not illustrated) of the engine 5 how the internal combustion engine is provided. In the embodiment of the present invention is the VVT system 1 with electric drive configured to be provided on the intake valve side.

The power machine 5 is configured to be one by a crankshaft 6th received power to an intake camshaft 11 and an exhaust camshaft 12 about sprockets 8th , 9 is transmitted by a synchronous or timing belt (or a timing chain) 7.

A crank wheel is on the crankshaft 6th attached and the crank angle sensor 2 is adjacent to the crankshaft 6th intended. A plurality of projections stand on an outer circumference of the crank wheel 13 emerged.

The cam wheel on the intake camshaft is similar 11 attached and the cam angle sensor 3 is adjacent to the intake camshaft 11 intended. A plurality of projections stand on an outer circumference of the cam wheel 14th emerged.

This crank wheel and cam wheel and this crank angle sensor 2 and cam angle sensor 3 basically the same as conventional ones.

The crank angle sensor can be more precise 2 output a pulse signal when the projection 13 the crank angle sensor on the crank wheel 2 happens. The cam angle sensor 3 can output a pulse signal when the projection 14th the cam wheel happens.

The engine ECU 51 receives the pulse signals described above and thus can determine a rotational frequency of the crankshaft 6th and a rotational frequency of the intake camshaft 11 calculate based on input intervals, an input number and the like of the pulse signals.

In the embodiment of the present invention, in addition to the engine ECU described above 51 a body ECU (as "B-ECU" in 2 ) 52, which is an electronic control unit that provides operation control for electrical equipment other than the prime mover 5 executes, and the like provided (see 2 ).

The body ECU 52 and the engine ECU 51 are each supplied with a power supply voltage from a vehicle battery (as "BAT" in 2 described) 22 via an ignition switch (in 2 described as "IG-SW") 21 supplied (see 2 ).

3 Fig. 13 is a flowchart of a subroutine for illustrating an operation of the processing for valve phase confirmation in starting the internal combustion engine according to the embodiment of the present invention, performed by the engine ECU 51 is performed. The following is a description of a content thereof with reference to FIG 3 respectively.

Similar to the related art, it is first assumed that the engine ECU 51 according to the embodiment of the present invention, executes so-called cylinder determination processing separately and simultaneously, and executes valve phase confirmation processing when the internal combustion engine is started in parallel. Various methods are available for determining the cylinder. However, there is no need to limit the method of determining the cylinder to a particular method.

Under such an assumption, when the ignition switch 21st is turned on with the power supply to the engine ECU 51 started and the VVT system 1 started with electric drive (see step S100 in 3 ).

Next, the valve phase is determined and the valve through the VVT system 1 driven by an electric drive (see step S200 in 3 ).

Here, before a detailed description of the processing for valve phase confirmation upon starting the internal combustion engine according to the embodiment of the present invention, a description will be given of an outline of an overall process of the processing.

Compared to the related art, the processing for valve phase confirmation when starting the internal combustion engine according to the embodiment of the present invention can shorten a starting time, improve reliability of starting and the like, particularly by immediately confirming the valve phase of the intake valve (not illustrated) and using the Valve phase for an internal combustion engine start control when starting the engine 5 .

A specific description of the processing for valve phase confirmation will be given below. First is in step S200 a target VVT angle, that is, a displacement amount (a rotation angle), of the intake camshaft 11 set to move the intake valve (not illustrated), in other words, to the intake camshaft 11 to turn. Next, the VVT actuator shifts 1a with electric drive the inlet valve (not illustrated) according to the target VVT angle.

The VVT actuator 1a with the electric drive is driven repeatedly several times based on this target VVT angle to finally locate the intake valve (not illustrated) at the most retarded position as a specified end point.

Here, the target VVT angle is not limited to any particular value. However, as will be described below, the intake valve is driven according to the target VVT angle, and it is driven based on a change in the output of the cam angle sensor 3 determines that Inlet valve (not illustrated) has reached the most retarded position. Accordingly, a relatively small angle is preferably selected for the target VVT angle.

Next, a valve phase deviation Δθ is calculated (see step S300 in 3 ).

Here is a time to take this step S300 is executed, the valve phase deviation Δθ is a difference between the output values of the cam angle sensor 3 before and after such a point in time.

For example, it becomes more specific in the case where the latest output value of the cam angle sensor 3 is set as θdet (n) and the output value of the cam angle sensor 3 immediately before this output value θdet (n) is set as θdet (n-1), the valve phase deviation Δθ is calculated as Δθ = θdet (n) - θdet (n-1).

Next, it is determined whether the cylinder determination processing has been completed (see step S400 in 3 ).

As above as the requirement for the engine ECU 51 According to the embodiment of the present invention has been described, the processing for cylinder determination is carried out separately from the processing for valve phase confirmation based on the conventional method.

If in step S400 When it is determined that the processing for cylinder determination is completed (if YES), the phase of the intake valve (not illustrated) (described below as an “intake valve phase” for convenience of description) is also confirmed. As a result, it is no longer necessary to carry out the valve phase confirmation processing when the internal combustion engine is started. In this case, therefore, the valve position control is performed when the engine is started 5 executed based on a result of the processing for cylinder determination and the ignition in the engine 5 started (see step S700 in 3 ).

If in step S400 on the other hand, when it is determined that the cylinder determination processing is not completed (if NO), the end point is determined using the valve phase deviation Δθ (see step S500 in 3 ).

That is, it is determined whether an absolute value of the valve phase deviation Δθ obtained in the above step S300 is calculated, is below a reference deviation θs.

This processing for determination is carried out from a perspective described below.

While the intake valve phase is being changed toward the most retarded position as a final target position according to the target VVT angle, there always occurs the difference between the most recent output value θdet (n) of the cam angle sensor 3 and the last output value θdet (n-1) of the cam angle sensor 3 on.

In other words, the most recent output value θdet (n) always becomes larger than the last output value θdet (n-1), and an amount of the difference corresponds to the rotation angle of the intake camshaft 11 by the VVT actuator 1a with electric drive.

However, once the intake valve phase reaches the most retarded position, there will be a change in the output of the cam angle sensor thereafter 3 theoretically terminated at the output value at the time. As a result, the valve phase deviation Δθ at this time is theoretically zero. In reality, however, the valve phase deviation Δθ may be due to a fluctuation in an output characteristic of the cam angle sensor 3 and the like cannot always be zero. For this reason, in the embodiment of the present invention, in the case where the absolute value of the valve phase deviation Δθ is less than the reference deviation θs, it is determined that the intake valve phase has reached the most retarded position.

Meanwhile in step S500 When it is determined that the absolute value of the valve phase deviation Δθ is below the reference deviation θs (if YES), it determines that the intake valve phase has reached the most retarded position as the specified end point. Then, the most retarded position of the intake valve phase at that time is set as a learning value of the intake valve phase in an appropriate storage area of the engine ECU 51 saved and retained (step S600 in 3 ).

Next is valve position control when the engine is started 5 based on the intake valve phase confirmed as described above and the ignition of the engine 5 started (see step S700 in 3 ).

Next, a description will be made of the processing for valve phase confirmation upon starting the internal combustion engine according to the embodiment of the present invention as a whole with reference to schematic graphs shown in FIG 4th are illustrated.

When the ignition switch 21st is switched on (see time t1 in 4A) and the VVT system 1 electrically driven by the engine ECU 51 is driven to slide the intake valve (not illustrated) to the most retarded position, setting the target VVT angle and driving the intake valve (not illustrated) by the VVT actuator 1a repeated several times with electric drive according to the target VVT angle (see time t2 further in 4B) .

In 4B become a change in the target VVT angle and a change in the valve phase (an actual angle) determined by the cam angle sensor 3 are recorded, each indicated by a line with two dots and a dash and a solid line. The changes in both the target VVT angle and the valve phase (the actual angle) correspond to each other in a period of time from when the VVT actuator drives the intake valve (not illustrated) 1a is started with an electric drive (the time t2 in 4B) until the time at which the actual angle reaches an end point position (time t4 in 4B) and in a period of time from when the actual angle is at the end point position to when the actual angle reaches an optimal VVT phase position. Consequently, the target VVT angle and the valve phase (the actual angle) should be indicated by a single line. In 4B however, to facilitate understanding, the target VVT angle and the valve phase (the actual angle) are illustrated in parallel with a small space therebetween.

While the intake valve (not illustrated) by the VVT actuator 1a is driven repeatedly with electric drive in accordance with the target VVT angle, starting is started as described above (see time t3 in FIG 4D ). In such a case, the engine speed is gradually increased (see FIG 4E) .

Meanwhile, as described above, the intake valve (not illustrated) is operated by the VVT actuator 1a further driven with electric drive according to the target VVT angle until the absolute value of the valve phase deviation Δθ is below the reference deviation θs. If it is determined that the absolute value of the valve phase deviation Δθ is below the reference deviation θs, then it is determined that the intake valve phase has reached the most retarded position as the end point (see time t5 in FIG 4C ).

At this point the VVT actuator is leading 1a with electric drive in the case where the cylinder determination is not completed by the processing for cylinder determination which is carried out separately from the processing for valve phase confirmation when the internal combustion engine is started (see time t6 in FIG 4F) the valve position control based on the intake valve phase confirmed by the processing for valve phase confirmation when the internal combustion engine is started, and the ignition in the engine 5 is started (see time t7 in 4G) .

The processing for valve phase confirmation when starting the internal combustion engine according to the embodiment of the present invention is applied as described above. As a result, compared with the case where the valve position at cranking is confirmed by the conventional cylinder determination processing, the possibilities of promptly confirming the valve position are increased and a cranking time is further shortened.

In addition, possibilities for ensuring a sufficient time for driving the intake valve from the confirmation of the valve position to the optimal valve phase for starting an engine are increased, and advantageous combustion at starting is ensured. As a result, compared with the related art, the number of occurrences of misfire and abnormal combustion is reduced.

Furthermore, since the starting time can be shortened, emissions of unburned hydrocarbons (HC) and harmful gases are reduced. A catalytic converter can be heated up immediately by shortening the starting time. As a result, an effect of reducing the emission of the harmful gas due to prompt heating of the catalyst can be expected.

The present invention can be applied to the vehicle for which the immediate confirmation of the valve position upon starting the internal combustion engine is desired.

Claims (6)

A method for confirming a valve phase in an internal combustion engine start, the method confirming a valve phase in an internal combustion engine start having a variable valve timing system configured to adjust the valve phase of the internal combustion engine, the method including: Shifting the valve phase to a most retarded position by the variable valve timing system upon starting the internal combustion engine; successively determining whether a valve phase deviation, that is, a difference between output values of a cam angle sensor at a consecutive time, is below a specified reference deviation; Confirming the valve phase that the valve phase has reached the most retarded position in the case where the valve phase deviation is below the reference deviation; and using the valve phase for starting control for the internal combustion engine. Method for confirming the valve phase when starting the internal combustion engine Claim 1 wherein the system is configured with variable valve timing to adjust the valve phase by electric drive and is used to adjust an intake valve phase. Method for confirming the valve phase when starting the internal combustion engine Claim 2 , further comprising: ending a series of the processing for confirming the valve phase in the case where the valve phase is not confirmed at a point of time when cylinder determination is completed in the processing for cylinder determination which is separately executed. Vehicle operation control configured to perform operation control for an internal combustion engine using an electronic control unit, the internal combustion engine having a variable valve timing system configured to adjust the valve phase of the internal combustion engine, the electronic control unit as follows configured to: shift the valve phase to a most retarded position by the variable valve timing system when starting the internal combustion engine; successively determining whether a valve phase deviation, that is, a difference between output values of a cam angle sensor at a consecutive time, is below a specified reference deviation; Confirming the valve phase that the valve phase has reached the most retarded position in the case where the valve phase deviation is below the reference deviation; and using the valve phase for starting control for the internal combustion engine. Vehicle operation control according to Claim 4 wherein the system is configured with variable valve timing to adjust the valve phase by electric drive and is used to adjust an intake valve phase. Vehicle operation control according to Claim 5 wherein the electronic control unit is configured to: separately execute cylinder determination processing for the internal combustion engine; and to end a series of the processing for confirming the valve phase in the case where the valve phase is not confirmed at a point of time when a cylinder determination in the processing for cylinder determination is completed.

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