JP4255754B2 - Control device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an internal combustion engine control apparatus, and more particularly to an internal combustion engine control apparatus provided with a cylinder deactivation mechanism that deactivates some cylinders of an internal combustion engine having a plurality of cylinders.
[0002]
[Prior art]
Patent Document 1 shows an internal combustion engine having a cylinder deactivation mechanism, in which a partial cylinder operation in which some cylinders are deactivated and an all cylinder operation in which all cylinders are operated are engine operation states. It is switched according to. Further, in the control device disclosed in Patent Document 1, in order to prevent the engine output torque from changing with the switching of the number of operating cylinders, the opening degree of the throttle valve is smaller during the partial cylinder operation than during the full cylinder operation. Control to increase the value is performed.
[0003]
Patent Document 2 discloses a fuel supply control method for increasing the amount of fuel supplied to the engine in a high load operation in which the throttle valve opening is larger than the high load determination opening.
[0004]
[Patent Document 1]
JP-A-11-336575 [Patent Document 2]
Japanese Examined Patent Publication No. 2-51054
[Problems to be solved by the invention]
FIG. 8 shows a change characteristic of the engine output torque with respect to the throttle valve opening TH, where the solid line corresponds to the all cylinder operation and the broken line corresponds to the partial cylinder operation. Here, in order to maintain the engine output torque at TRQ0 shown in the figure when shifting from the full cylinder operation to the partial cylinder operation, it is necessary to increase the throttle valve opening TH from THAC to THPC. As a result, since the throttle valve opening TH exceeds the high load determination opening THWOT shown in Patent Document 2, an unnecessary amount of fuel is increased, resulting in deterioration of fuel consumption.
[0006]
The present invention has been made paying attention to this point, and provides a control device capable of appropriately increasing the amount of fuel during high-load operation in an internal combustion engine having a cylinder deactivation mechanism and preventing deterioration of fuel consumption. For the purpose.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 has a plurality of cylinders, all-cylinder operation for operating all of the plurality of cylinders, and partial cylinder for stopping operation of some of the plurality of cylinders. In the control device for an internal combustion engine provided with switching means (30) for switching between operation, the engine operating parameters (TW, TH, TA, etc.) including the opening (TH) of a throttle valve provided in the intake system of the engine NE), an instruction means for instructing the switching means to perform the all-cylinder operation or the partial cylinder operation according to the operation parameter detected by the operation parameter detection means, and the instruction means A high load determination opening (THWOT) for determining that the engine is in a high load operation state when all cylinder operation is commanded is set based on the engine speed (NE). High and load determination opening setting means, when the opening degree of the throttle valve is greater than the high load threshold opening (THWOT), and increase correction means for increasing correction of the fuel amount supplied (TOUT) to the institution, Correction prohibiting means for prohibiting the increase correction by the increase correction means during the partial cylinder operation, and the command means operates when the throttle valve opening is smaller than a determination threshold (THCS). To the switching means, the determination threshold value (THCS) is determined based on the vehicle speed (VP) of the vehicle driven by the engine and the gear position (GP) of the transmission of the vehicle, and the vehicle speed (VP) There characterized that you set the determination threshold value (THCS) so large as to increase.
[0008]
According to this configuration, the high load determination opening for determining that the engine is in a high load operation state during all cylinder operation is set based on the engine speed, and the throttle valve opening is during all cylinder operation. The fuel supply amount is increased when the opening is larger than the high load determination opening, while the fuel amount increase correction is not performed during partial cylinder operation even if the throttle valve opening exceeds the high load determination opening. . Therefore, unnecessary fuel increase is not performed, and deterioration of fuel consumption can be prevented.
According to a second aspect of the present invention, in the control device for an internal combustion engine according to the first aspect, the increase correction means determines whether or not the throttle valve opening is larger than the high load determination opening. It is characterized by performing with.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram showing a configuration of an internal combustion engine and a control device thereof according to an embodiment of the present invention. A V-type 6-cylinder internal combustion engine (hereinafter simply referred to as “engine”) 1 includes a right bank provided with # 1, # 2 and # 3 cylinders, and a left bank provided with # 4, # 5 and # 6 cylinders. And a cylinder deactivation mechanism 30 for temporarily deactivating the # 1 to # 3 cylinders is provided in the right bank. FIG. 2 is a diagram showing a hydraulic circuit for hydraulically driving the cylinder deactivation mechanism 30 and its control system. This diagram is also referred to in conjunction with FIG.
[0010]
A throttle valve 3 is arranged in the middle of the intake pipe 2 of the engine 1. The throttle valve 3 is provided with a throttle valve opening sensor 4 for detecting the opening TH of the throttle valve 3, and a detection signal thereof is supplied to an electronic control unit (hereinafter referred to as “ECU”) 5.
[0011]
A fuel injection valve 6 is provided for each cylinder slightly upstream of an intake valve (not shown). Each injection valve is connected to a fuel pump (not shown) and electrically connected to the ECU 5 to receive a signal from the ECU 5. Thus, the valve opening time of the fuel injection valve 6 is controlled.
[0012]
An intake pipe absolute pressure (PBA) sensor 7 is provided immediately downstream of the throttle valve 3, and an absolute pressure signal converted into an electric signal by the absolute pressure sensor 7 is supplied to the ECU 5. An intake air temperature (TA) sensor 8 is attached downstream of the intake pipe absolute pressure sensor 7 to detect the intake air temperature TA and supply a corresponding electrical signal to the ECU 5.
[0013]
An engine water temperature (TW) sensor 9 mounted on the main body of the engine 1 is composed of a thermistor or the like, detects the engine water temperature (cooling water temperature) TW, outputs a corresponding temperature signal, and supplies it to the ECU 5.
A crank angle position sensor 10 that detects a rotation angle of a crankshaft (not shown) of the engine 1 is connected to the ECU 5, and a signal corresponding to the rotation angle of the crankshaft is supplied to the ECU 5. The crank angle position sensor 10 is a cylinder discrimination sensor that outputs a pulse (hereinafter referred to as “CYL pulse”) at a predetermined crank angle position of a specific cylinder of the engine 1, and relates to a top dead center (TDC) at the start of the intake stroke of each cylinder. A TDC sensor that outputs a TDC pulse at a crank angle position before a predetermined crank angle (every 120 degrees of crank angle in a 6-cylinder engine) and a CRK that generates a CRK pulse at a constant crank angle period shorter than the TDC pulse (for example, a period of 30 degrees). It consists of sensors, and a CYL pulse, a TDC pulse and a CRK pulse are supplied to the ECU 5. These signal pulses are used for various timing controls such as fuel injection timing and ignition timing, and detection of engine speed (engine speed) NE.
[0014]
The cylinder deactivation mechanism 30 is hydraulically driven using the lubricating oil of the engine 1 as hydraulic oil. The hydraulic oil pressurized by the oil pump 31 is supplied to the cylinder deactivation mechanism 30 via the oil passage 32, the intake side oil passage 33i, and the exhaust side oil passage 33e. An intake-side solenoid valve 35i and an exhaust-side solenoid valve 35e are provided between the oil passage 32 and the oil passages 33i and 33e. These solenoid valves 35i and 35e are connected to the ECU 5, and the operation thereof is performed by the ECU 5. Be controlled.
[0015]
The oil passages 33i and 33e are provided with hydraulic switches 34i and 34e that are turned on when the operating oil pressure drops below a predetermined threshold, and the detection signals are supplied to the ECU 5. Further, a hydraulic oil temperature sensor 33 for detecting the hydraulic oil temperature TOIL is provided in the middle of the oil passage 32, and a detection signal thereof is supplied to the ECU 5.
[0016]
A specific configuration example of the cylinder deactivation mechanism 30 is disclosed in, for example, Japanese Patent Laid-Open No. 10-103097, and the same mechanism is used in this embodiment. According to this mechanism, when the solenoid valves 35i and 35e are closed and the hydraulic pressure in the oil passages 33i and 33e is low, the intake valves and exhaust valves of the cylinders (# 1 to # 3) are normally opened and closed. On the other hand, when the solenoid valves 35i, 35e are opened and the hydraulic pressure in the oil passages 33i, 33e increases, the intake valves and exhaust valves of the cylinders (# 1 to # 3) maintain the closed state. That is, while the solenoid valves 35i and 35e are closed, all cylinders are operated to operate all cylinders. When the solenoid valves 35i and 35e are opened, the cylinders # 1 to # 3 are deactivated, and # 4 to Partial cylinder operation in which only # 6 cylinder is operated is performed.
[0017]
An exhaust gas recirculation passage 21 is provided between the downstream side of the throttle valve 3 of the intake pipe 2 and the exhaust pipe 13, and an exhaust gas recirculation valve (hereinafter referred to as an exhaust gas recirculation valve) that controls the exhaust gas recirculation amount in the middle of the exhaust gas recirculation passage 21. 22 (referred to as “EGR valve”). The EGR valve 22 is an electromagnetic valve having a solenoid, and the valve opening degree is controlled by the ECU 5. The EGR valve 22 is provided with a lift sensor 23 for detecting the valve opening degree (valve lift amount) LACT, and the detection signal is supplied to the ECU 5. An exhaust gas recirculation mechanism is configured by the exhaust gas recirculation passage 21 and the EGR valve 22.
[0018]
A spark plug 12 provided for each cylinder of the engine 1 is connected to the ECU 5, and a drive signal of the spark plug 12, that is, an ignition signal is supplied from the ECU 5.
The ECU 5 includes an atmospheric pressure sensor 14 that detects the atmospheric pressure PA, a vehicle speed sensor 15 that detects the traveling speed (vehicle speed) VP of the vehicle driven by the engine 1, and a gear position that detects the gear position GP of the transmission of the vehicle. Sensors 16 are connected, and detection signals from these sensors are supplied to the ECU 5.
[0019]
The ECU 5 shapes input signal waveforms from various sensors, corrects the voltage level to a predetermined level, converts an analog signal value into a digital signal value, etc., and a central processing circuit (hereinafter referred to as “CPU”). A storage circuit that stores various calculation programs executed by the CPU, calculation results, and the like, an output circuit that supplies a drive signal to the fuel injection valve 6, and the like. The ECU 5 controls the valve opening time, the ignition timing, and the opening degree of the EGR valve 22 based on detection signals from various sensors, and opens and closes the electromagnetic valves 35i and 35e, thereby Switching control between cylinder operation and partial cylinder operation is performed.
[0020]
The CPU of the ECU 5 calculates the valve opening time TOUT of the fuel injection valve 6 that operates in synchronization with the TDC pulse by the following equation (1).
TOUT = TIM × KWOT × K1 + K2 (1)
TIM is a basic fuel amount, specifically, a basic fuel injection time of the fuel injection valve 6, and is determined by searching a TI map set according to the engine speed NE and the intake pipe absolute pressure PBA. The TI map is set so that the air-fuel ratio of the air-fuel mixture supplied to the engine becomes substantially the stoichiometric air-fuel ratio in the operating state corresponding to the engine speed NE and the intake pipe absolute pressure PBA. That is, the basic fuel amount TIM has a value substantially proportional to the intake air amount (mass flow rate) of the engine 1 per 1 TDC period (time interval between adjacent TDC pulses).
[0021]
KWOT is set to a value larger than “1.0” in a high load operation state in which the throttle valve opening TH exceeds the high load determination opening THWOT, and is set to “1.0” otherwise. It is an increase coefficient. By the high load increase coefficient KWOT, the fuel supply amount is increased in the high load operation state where the throttle valve opening TH exceeds the high load determination opening THWOT.
[0022]
K1 and K2 are other correction coefficients and correction variables that are calculated according to various engine parameter signals, respectively, and are predetermined values that can optimize various characteristics such as fuel consumption characteristics and engine acceleration characteristics according to engine operating conditions. Determined by value.
[0023]
FIG. 3 is a flowchart of processing for determining execution conditions of cylinder deactivation (partial cylinder operation) for deactivating some cylinders. This process is executed by the CPU of the ECU 5 every predetermined time (for example, 10 milliseconds).
In step S11, it is determined whether or not the start mode flag FSTMOD is “1”. If FSTMOD = 1 and the engine 1 is being started (cranking), the detected engine water temperature TW is used as the start mode water temperature. Store as TWSTMOD (step S13). Next, the TMTWCSDLY table shown in FIG. 4 is searched according to the start mode water temperature TWSTMOD, and the delay time TMTWCSDLY is calculated. In the TMTWCSDLY table, the delay time TMTWCSDLY is set to a predetermined delay time TDLY1 (for example, 250 seconds) and the start mode water temperature TWSTMOD is set to the first predetermined water temperature in the range where the start mode water temperature TWSTMOD is equal to or lower than the first predetermined water temperature TW1 (for example, 40 ° C.). In the range higher than TW1 (for example, 40 ° C.) and lower than the second predetermined water temperature TW2 (for example, 60 ° C.), the delay time TMTWCSDLY is set to decrease as the start mode water temperature TWSTMOD increases, and the start mode water temperature TWSTMOD becomes the second predetermined water temperature. In a range higher than TW2, the delay time TMTWCSDLY is set to “0”.
[0024]
In the following step S15, the downcount timer TCSWAIT is set to the delay time TMTWCSDLY and started, and the cylinder deactivation flag FCYLSTP is set to “0” (step S24). This indicates that the execution condition for cylinder deactivation is not satisfied.
[0025]
If FSTMOD = 0 in step S11 and the normal operation mode is set, it is determined whether or not the engine water temperature TW is higher than the cylinder deactivation determination temperature TWCSTP (for example, 75 ° C.) (step S12). When TW ≦ TWCSTP, it is determined that the execution condition is not satisfied, and the process proceeds to step S14. When the engine water temperature TW is higher than the cylinder deactivation determination temperature TWCSTP, the process proceeds from step S12 to step S16, and it is determined whether or not the value of the timer TCSWAIT started in step S15 is “0”. While TCSWAIT> 0, the process proceeds to step S24, and when TCSWAI = 0, the process proceeds to step S17.
[0026]
In step S17, the THCS table shown in FIG. 5 is searched according to the vehicle speed VP and the gear position GP, and the upper threshold THCSH and the lower threshold THCSL used for the determination in step S18 are calculated. In FIG. 5, the solid line corresponds to the upper threshold value THCSH, and the broken line corresponds to the lower threshold value THCSL. The THCS table is set for each gear position GP, and is set such that the upper threshold THCSH and the lower threshold THCSL increase as the vehicle speed VP increases roughly at each gear position (second to fifth gears). Has been. However, when the gear position GP is the second speed, an area is provided in which the upper threshold value THCSH and the lower threshold value THCSL are kept constant even if the vehicle speed VP changes. When the gear position GP is 1st gear, all cylinder operation is always performed, so the upper threshold value THCSH and the lower threshold value THCSL are set to “0”, for example. If the vehicle speed VP is the same, the threshold values (THCSH, THCSL) corresponding to the low-speed side gear position GP are set to be larger than the threshold values (THCSH, THCSL) corresponding to the high-speed side gear position GP.
[0027]
In step S18, it is determined with hysteresis whether or not the throttle valve opening TH is smaller than the threshold value THCS. Specifically, when the cylinder deactivation flag FCYLSTP is “1”, when the throttle valve opening TH increases and reaches the upper threshold THCSSH, the answer to step S18 is negative (NO), and the cylinder deactivation flag FCYLSTP is When it is “0”, when the throttle valve opening TH decreases and falls below the lower threshold value THCSL, the answer to step S18 becomes affirmative (YES).
[0028]
If the answer to step S18 is affirmative (YES), it is determined whether or not the atmospheric pressure PA is equal to or higher than a predetermined pressure PACS (for example, 86.6 kPa (650 mmHg)) (step S19), and the answer is affirmative (YES) ), It is determined whether or not the intake air temperature TA is equal to or higher than a predetermined lower limit temperature TACSL (eg, −10 ° C.) (step S20). If the answer is affirmative (YES), the intake air temperature TA is predetermined. It is determined whether or not the temperature is lower than an upper limit temperature TACSH (for example, 45 ° C.) (step S21). If the answer is affirmative (YES), it is determined whether or not the engine speed NE is lower than a predetermined speed NECS. (Step S22). The determination in step S22 is performed with hysteresis as in step S18. That is, when the cylinder deactivation flag FCYLSTP is “1”, when the engine speed NE increases and reaches the upper speed NECSH (for example, 3500 rpm), the answer to step S22 becomes negative (NO), and the cylinder deactivation flag FCYLSTP When the engine speed NE decreases and falls below the lower speed NECSL (for example, 3300 rpm), the answer to step S22 is affirmative (YES).
[0029]
When the answer to any of steps S18 to S22 is negative (NO), it is determined that the cylinder deactivation execution condition is not satisfied, and the process proceeds to step S24. On the other hand, when all the answers to steps S18 to S22 are affirmative (YES), it is determined that the cylinder deactivation execution condition is satisfied, and the cylinder deactivation flag FCYLSTP is set to “1” (step S23).
[0030]
When the cylinder deactivation flag FCYLSTP is set to “1”, a partial cylinder operation is performed in which the # 1 to # 3 cylinders are deactivated and the # 4 to # 6 cylinders are operated, and the cylinder deactivation flag FCYLSTP is set to “0”. ”Is set, the all-cylinder operation for operating all the cylinders # 1 to # 6 is executed.
[0031]
FIG. 6 is a flowchart of processing for setting the high load operation flag FTHWOT. This process is executed by the CPU of the ECU 5 in synchronization with the generation of the TDC pulse. When the high load operation flag FTHWOT is set to “1”, the high load increase coefficient KWOT is set to a value larger than “1.0”, and the fuel supply amount is increased.
[0032]
In step S31, it is determined whether or not a cylinder deactivation flag FCYLSTP is “1”. If the answer is affirmative (YES) and some cylinders are operating, the process immediately proceeds to step S38, and the high load operation flag FTHWOT is set to "0".
[0033]
When FCYLSTP = 0 and all cylinders are operating, it is determined whether or not the high load operation flag FTHWOT is “1” (step S32). When FTHWOT = 0 and the engine is not operating at a high load, a THWOTH table indicated by a solid line in FIG. 7 is searched according to the engine speed NE to calculate an upper high load determination opening THWOTH (step S35). Next, the high load determination opening THWOT is set to the upper high load determination opening THWOTH (step S36), and the process proceeds to step S37.
[0034]
When FTHWOT = 1 in step S32 and high load operation is being performed, a THWOTL table indicated by a broken line in FIG. 7 is searched according to the engine speed NE to calculate the lower high load determination opening THWOTL (step S32). S33). Next, the high load determination opening THWOT is set to the lower high load determination opening THWOT (step S34), and the process proceeds to step S37.
[0035]
In step S37, it is determined whether or not the throttle valve opening TH is larger than the high load determination opening THWOT. When TH> THWOT, the high load operation flag FTHWOT is set to “1” (step S39), and when TH ≦ THWOT, the high load operation flag FTHWOT is set to “0” (step S38). ). By steps S32 to S36, the determination in step S37 is executed with hysteresis.
[0036]
According to the processing of FIG. 6, the high load operation flag FTHWOT is held at “0” regardless of the throttle valve opening TH during partial cylinder operation, and the high load increase of the fuel supply amount is not performed. Therefore, as shown in FIG. 8, even when the throttle valve opening TH is increased, the fuel increase is not performed in order to make the torque the same at the time of the transition from the full cylinder operation to the partial cylinder operation. As a result, fuel consumption can be prevented from deteriorating.
[0037]
In the present embodiment, the cylinder deactivation mechanism 30 constitutes a switching means, and the throttle valve opening sensor 4, the intake air temperature sensor 8, the engine water temperature sensor 9, and the crank angle position sensor 10 constitute an operating parameter detection means, and the ECU 5 Constitutes command means, increase correction means, and correction prohibition means. More specifically, the process in FIG. 3 corresponds to the command unit, steps S32 to S37 and S39 in FIG. 6 correspond to the increase correction unit, and steps S31 and S38 in FIG. 6 correspond to the correction prohibition unit.
[0038]
The present invention is not limited to the embodiment described above, and various modifications can be made. For example, the upper high load determination opening THWOTH and the lower high load determination opening THWOTL may be set to constant values that do not depend on the engine speed NE.
The present invention can also be applied to control of a marine vessel propulsion engine such as an outboard motor having a crankshaft as a vertical direction.
[0039]
【The invention's effect】
As described above in detail, according to the first aspect of the present invention, the high load determination opening for determining that the engine is in the high load operation state during all cylinder operation is set based on the engine speed. The fuel supply amount is increased when the throttle valve opening is larger than the high load determination opening during all cylinder operation, while some cylinders are operating even if the throttle valve opening exceeds the high load determination opening The fuel amount increase correction is not performed. Therefore, unnecessary fuel increase is not performed, and deterioration of fuel consumption can be prevented.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of an internal combustion engine and a control device thereof according to an embodiment of the present invention.
FIG. 2 is a diagram showing a configuration of a hydraulic control system of a cylinder deactivation mechanism.
FIG. 3 is a flowchart of a process for determining a cylinder deactivation condition.
4 is a diagram showing a TMTWCSDLY table used in the processing of FIG. 3. FIG.
FIG. 5 is a diagram showing a THCS table used in the process of FIG. 3;
FIG. 6 is a flowchart of processing for setting a high load operation flag (FTHWOT).
7 is a diagram showing a table used in the process of FIG. 6. FIG.
FIG. 8 is a graph showing a relationship between throttle valve opening (TH) and engine output torque.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Intake pipe 3 Throttle valve 4 Throttle valve opening sensor (operating parameter detection means)
5 Electronic control unit (command means, increase correction means, correction prohibition means)
8 Intake air temperature sensor (operating parameter detection means)
9 Engine water temperature sensor (operating parameter detection means)
10 Crank angle position sensor (operating parameter detection means)
30 cylinder deactivation mechanism (switching means)

Claims (2)

In a control device for an internal combustion engine having a plurality of cylinders and comprising switching means for switching between all-cylinder operation for operating all of the plurality of cylinders and partial cylinder operation for stopping operation of some of the plurality of cylinders. ,
An operation parameter detection means for detecting an operation parameter of the engine, including an opening degree of a throttle valve provided in an intake system of the engine;
Command means for instructing the switching means to perform the all-cylinder operation or the partial cylinder operation according to the operation parameter detected by the operation parameter detection means;
A high load determination that sets a high load determination opening for determining that the engine is in a high load operation state when the command means commands the all-cylinder operation based on the rotational speed of the engine. Opening setting means;
When the opening degree of the throttle valve is larger than the high load threshold opening, and increase correction means for increasing correction of the fuel amount supplied to the engine,
Correction prohibiting means for prohibiting increase correction by the increase correction means during the partial cylinder operation ,
The command means instructs the switching means to perform the partial cylinder operation when the opening degree of the throttle valve is smaller than a determination threshold, and sets the vehicle speed driven by the engine and the gear position of the transmission of the vehicle. based on the determined determination threshold value, the control apparatus for an internal combustion engine the vehicle speed, characterized in that you set the determination threshold to be greater enough to increase.   2. The control device for an internal combustion engine according to claim 1, wherein the increase correction means executes determination of whether or not the throttle valve opening is larger than the high load determination opening with hysteresis. 3.

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