JP2004143982A - Engine speed control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce exhaust emissions by setting a target engine speed in response to engine cooling water temperature when warming up the engine after starting so that the stabilized burning of an engine can be performed, occurrence of misfire can be prevented and failure of driveability caused by engine vibration can be improved. <P>SOLUTION: This engine speed control device controls an idle control valve so that an idling speed can be set to the target engine speed. After the engine is started, a first target engine speed in response to the engine cooling walter temperature is set, and after the first target engine speed is retained and controlled by time relative to the engine cooling water temperature, the engine cooling water temperature when finishing retention and control is detected, and damping and control are performed up to a second target engine speed by an attenuation in response to the engine cooling water temperature. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an engine speed control device, and particularly to setting a target engine speed in accordance with the temperature of engine cooling water, enabling stable combustion of the engine, preventing occurrence of misfire, and causing engine vibration. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine speed control device capable of improving poor drivability and reducing exhaust gas emission.
[0002]
[Prior art]
In order to stabilize the engine speed after the cold start, the engine mounted on a vehicle or the like is supplied with the idle air supplied around the throttle valve provided in the intake passage during the idle operation when the engine is started. There is a device provided with a control device that adjusts an air flow rate and controls the engine speed to reach a target engine speed.
[0003]
The engine control device includes a throttle valve in an intake passage of the engine, a bypass passage bypassing the throttle valve and communicating with the intake passage, and an idle control valve for adjusting a bypass air flow rate in the bypass passage. During idle operation when the engine is started, as shown by the solid line in FIG. 4 of JP-A-11-141446, idle control is performed so that the engine speed NE becomes the target engine speed NEset set according to the coolant temperature. Control the valve.
[0004]
Further, the engine is provided with a catalytic converter for purifying harmful components in exhaust gas in an exhaust passage. When the temperature of the catalyst reaches the activation temperature, the catalytic converter effectively functions to purify exhaust harmful components.
[0005]
Therefore, in the conventional engine control device, at the time of cold start of the engine, in order to quickly raise the temperature of the catalyst to the activation temperature to promote the purification of harmful exhaust components, the ignition timing is set to be lower than the normal target ignition timing. There is also a control that controls the retard side target ignition timing set to the retard side.
[0006]
[Patent Document 1]
JP-A-11-141446 (Pages 2-4, FIGS. 1, 2, and 4)
[0007]
As an engine speed control device, there is one disclosed in JP-A-11-141446. The engine control device disclosed in this publication includes a throttle valve provided in an intake passage of the engine, a bypass passage bypassing the throttle valve and communicating with the intake passage, and adjusting a bus path air flow rate of the bypass passage. An engine control device, comprising: an idle control valve, wherein the engine control device controls an idle control valve so that an engine speed becomes a target engine speed set in accordance with a coolant temperature during an idle operation when the engine is started. Until the set time has elapsed since the start of the ignition, the ignition timing is controlled to be the normal target ignition timing, and when the set time has elapsed, the normal target ignition timing is gradually shifted to the retard side target ignition timing. Control means for controlling the ignition timing to reach the retarded target ignition timing. And obtained by reducing the occurrence of harmful exhaust components in the state wall temperature is low chamber, and early removal of harmful exhaust components.
[0008]
[Problems to be solved by the invention]
By the way, in the engine speed control at the start disclosed in the above-mentioned Japanese Patent Application Laid-Open No. H11-141446, the engine speed is set to a target engine speed (also referred to as a “target speed”) NSET1 for a time T1 from the start. Thereafter, the engine speed is shifted slowly so that the target engine speed becomes NSET (see FIG. 6).
[0009]
However, the time (T1) at which the engine reaches stable combustion after the cold start depends on the temperature of the internal combustion engine at the time of startup, and the lower the temperature, the longer the time at which stable combustion is reached.
[0010]
However, in the technology disclosed in Japanese Patent Application Laid-Open No. H11-141446, the above-mentioned point is not clarified. If the time T1 is set to one fixed time, when the engine is at a very low temperature and when the engine is not at a very low temperature, If the combustion state of the engine is different, for example, if the control is performed at −30 degrees while maintaining stable combustion at 20 degrees, the engine will not stably burn, causing misfiring, increasing engine vibration, and reducing exhaust gas. However, there is a disadvantage that the amount of waste gas increases.
[0011]
Conversely, if the control is performed at a temperature of 20 degrees or more while the combustion time is stable at -30 degrees, the engine speed at the time of starting will remain high forever, leading to an increase in fuel consumption and an increase in engine noise. There is a disadvantage that it goes.
[0012]
[Means for Solving the Problems]
Therefore, in order to eliminate the above-mentioned inconvenience, the present invention provides a throttle valve in an intake passage of an engine, a bypass passage for bypassing an upstream side and a downstream side of the throttle valve, and an air passage of the bypass passage in the bypass passage. In an engine speed control device for providing an idle control valve capable of adjusting a flow rate, providing an engine coolant temperature detecting means capable of detecting an engine coolant temperature, and controlling the idle control valve so that an idling speed becomes a target engine speed. After the engine is started, a first target engine speed corresponding to the engine cooling water temperature is set, and the first target engine speed is held and controlled for a time corresponding to the engine cooling water temperature. Detects engine cooling water temperature and reduces to the second target engine speed with the amount of attenuation corresponding to engine cooling water temperature And controlling.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
According to the invention described above, after the engine is started, the first target engine speed corresponding to the engine coolant temperature is set, and the first target engine speed is maintained and controlled for a time corresponding to the engine coolant temperature. The engine cooling water temperature at the end of the holding control is detected, damping control is performed to a second target engine speed with a damping amount corresponding to the engine cooling water temperature, and the target engine speed is controlled according to the engine cooling water temperature at the time of warm-up after starting. The number is set, stable combustion of the engine becomes possible, misfires are prevented, drivability failure due to engine vibration can be improved, and exhaust gas emissions are reduced.
[0014]
【Example】
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0015]
1 to 6 show an embodiment of the present invention. In FIG. 2, 2 is an engine, 4 is an intake passage, and 6 is an exhaust passage.
[0016]
This engine 2 has a first cylinder bank 8 on one side and a second cylinder bank 10 on the other side arranged in a V-shape.
[0017]
An air cleaner 12, an intake air temperature sensor 14, a mass air flow sensor 16, and a throttle valve 18 are sequentially arranged in the intake passage 4 from the upstream side. The first branch intake passage 4-1 is connected to a combustion chamber (not shown) on the first cylinder bank 8 side and provided in the second branch intake passage 4-1. The branch intake passage 4-2 is provided so as to be connected to a combustion chamber (not shown) on the second cylinder bank 10 side.
[0018]
The throttle valve 18 is provided with a throttle opening sensor 20 for detecting the throttle opening of the throttle valve 18 and a bypass passage 22 for bypassing the upstream side and the downstream side of the throttle valve 18. An idle control valve (also referred to as “idle air control valve”) 24 capable of adjusting the air flow rate in the bypass passage 22 is provided in the middle of the bypass passage 22.
[0019]
Further, the exhaust passage 6 is provided by branching the upstream side into two first and second branch exhaust passages 6-1 and 6-2, and the first branch exhaust passage 6-1 is connected to the first cylinder bank 8 A second branch exhaust passage 6-2 is provided so as to be connected to a combustion chamber (not shown) on the second cylinder bank 10 side.
[0020]
The first catalytic converter 26-1 is provided in the middle of the first branch exhaust passage 6-1, and the second catalytic converter 26-2 is provided in the middle of the second branch exhaust passage 6-2. A first front-side O2 sensor 28-1 for detecting the oxygen concentration in the exhaust gas is provided at a position upstream of the first catalytic converter 26-1 in the middle of the first catalytic converter 26-1. A first rear O2 sensor 30-1 is provided at a position downstream of the catalytic converter 26-1.
[0021]
A second front-side O2 sensor 28-2 is provided at a position upstream of the second catalytic converter 26-2 in the middle of the second branch exhaust passage 6-2, and a second catalytic converter in the middle of the second branch exhaust passage 6-2. A second rear O2 sensor 30-2 is provided at a position downstream of 26-2.
[0022]
Furthermore, the first and second branch exhaust passages 6-1 and 6-2 are joined at a portion downstream of the first and second rear-side O2 sensors 30-1 and 30-2, and from the joined portion. A three-way catalytic converter 32 is provided in the exhaust passage 6 on the downstream side.
[0023]
The engine 2 is provided with a fuel injection valve 34 directed to each combustion chamber (not shown). The fuel injection valve 34 is connected to a fuel tank 38 by a fuel supply passage 36. The fuel in the fuel tank 38 is fed under pressure by a fuel pump 40, dust is removed by a fuel filter 42, and supplied to the fuel injection valve 34 through a fuel supply passage 36.
[0024]
In the middle of the fuel supply passage 36, a fuel pressure adjusting section 44 for adjusting the fuel pressure is provided in communication. The fuel pressure adjusting unit 44 adjusts the fuel pressure to a constant value by the intake pressure introduced from the pressure guiding passage 46 communicating with the intake passage 4, and returns excess fuel to the fuel tank 38 through the fuel return passage 48. The fuel tank 38 is provided with a fuel level sensor 50 and a pressure sensor 52.
[0025]
The fuel tank 38 is provided in communication with the intake passage 4 on the downstream side of the throttle valve 18 by a fuel vapor passage 54, and a canister 56 is provided in the middle of the fuel vapor passage 54.
[0026]
The engine 2 is provided with EGR control means 58. The EGR control means 58 is provided with an EGR valve 60 for adjusting the EGR amount of the exhaust gas recirculated from the exhaust system to the intake system. The EGR valve 60 includes a second branch exhaust passage 6-2 upstream of the second front-side O2 sensor 28-2 of the exhaust system and first and second branch intake passages 4-1 and 4-2 of the intake system. The EGR passage 62 is provided in the EGR passage 62 which communicates with the confluence of the EGR. The operation is electronically controlled to adjust the EGR amount.
[0027]
Reference numeral 64 denotes a PCV valve.
[0028]
The intake air temperature sensor 14, the mass air flow sensor 16, the throttle opening sensor 20, the idle air control valve 24, the first front O2 sensor 28-1, and the first rear O2 sensor 30-1 , The second front-side O2 sensor 28-2, the second rear-side O2 sensor 30-2, the fuel injection valve 34, the fuel pump 40, the pressure sensor 52, and the EGR valve 60 are controlled by control means (“ECM”). ).
[0029]
The control means 66 includes a camshaft position sensor 68, an intake pressure sensor 70, an ignition coil assembly 72, a water temperature sensor 74 which is an engine water temperature detecting means capable of detecting an engine cooling water temperature, a crank angle sensor 76, An indicator lamp 78, a connection terminal 80, a power steering pressure switch 82, a heater blower fan switch 84, a cruise control module 86, a vehicle speed sensor 88, a combination meter 90, an A / D condenser fan relay 92, , A / C controller 94, data link connector 96, ABS controller module 98, main relay 100, ignition switch 102, P / N position switch 104, battery 106, starter switch 108, O / D off lamp 110, power lamp 112, lighting switch 114, stop lamp switch 116, O / D cut switch 118, power / normal change switch 120, 4WD LOW switch 122, transmission range switch 124 , A first solenoid valve 126, a second solenoid valve 128, a TCC solenoid valve 130, an A / T input speed sensor 132, and an A / T output speed sensor 134 that are connected to each other.
[0030]
Then, the control means 66 controls the idle control valve 24 so that the idling speed becomes the target engine speed.
[0031]
At this time, after the engine is started, a first target engine speed corresponding to the engine coolant temperature is set in the control means 66, and the first target engine speed is held for a time corresponding to the engine coolant temperature. After the control, the engine cooling water temperature at the end of the holding control is detected, and a function of damping control to a second target engine speed with a damping amount corresponding to the engine cooling water temperature is added.
[0032]
More specifically, the control means 66 sets the target engine speed after the engine is started to the first target engine speed NSET1 according to the engine coolant temperature as shown in FIG.
[0033]
Then, as shown in FIG. 4, the control means 66 sets a holding time T1 of the first target engine speed NSET1 according to the engine cooling water temperature, and holds and controls the first target engine speed NSET1 for the holding time T1. I do.
[0034]
Further, after the holding control, the control means 66 detects the engine cooling water temperature at the end of the holding control, and sets an attenuation amount TGEN according to the engine cooling water temperature as shown in FIG. The damping control is performed until the target engine speed NSET reaches 2.
[0035]
At this time, the second target engine speed NSET is a value set according to the engine coolant temperature, as shown in FIG.
[0036]
Next, the operation will be described with reference to the rotational speed control flowchart of FIG.
[0037]
When the control program (ISC control) is started (202), it is determined whether or not the engine has been started (204). If this determination (204) is NO, the determination (204) becomes YES. Until the determination (204) is YES, the target engine speed of the ISC control is set to the first target engine speed NSET1 (206). At this time, the first target engine speed NSET1 is set by the engine coolant temperature as shown in FIG.
[0038]
After setting the first target engine speed NSET1, as shown in FIG. 4, a holding time T1 of the first target engine speed NSET1 is set based on the engine cooling water temperature. The holding control of the target engine speed NSET1 is performed (208).
[0039]
Then, it is determined whether or not the holding time T1 has elapsed (210). If the determination (210) is NO, the holding control (208) of the first target engine speed NSET1 based on the holding time T1 is performed. Returning, if the determination (210) is YES, the engine coolant temperature at the end of the holding control is detected, and as shown in FIG. 5, an attenuation amount TGEN corresponding to the engine coolant temperature is set, and this attenuation amount TGEN is used. The damping control is performed up to the second target engine speed NSET (212).
[0040]
After this damping control, as shown in FIG. 3, control (214) is performed at a second target engine speed NSET set by the engine coolant temperature, and the control program (ISC control) ends (216). It becomes.
[0041]
As a result, the target engine speed is set according to the engine cooling water temperature at the time of warm-up after startup, so that stable combustion of the engine is possible, misfire is prevented from occurring, and the driver caused by engine vibration is generated. It is possible to improve the performance defect and reduce the amount of exhaust gas emission, which is practically advantageous.
[0042]
Further, by setting the second target engine speed NSET to a value corresponding to the engine coolant temperature, highly accurate control capable of reducing fuel consumption can be performed.
[0043]
Note that the present invention is not limited to the above-described embodiment, and various application modifications are possible.
[0044]
For example, in the embodiment of the present invention, after the engine is started, a first target engine speed is set according to the engine coolant temperature, and the first target engine speed is maintained and controlled for a time corresponding to the engine coolant temperature. After that, the engine cooling water temperature at the end of the holding control is detected, and the damping control is performed to the second target engine speed with the damping amount corresponding to the engine cooling water temperature. However, the control is performed in consideration of the minimum value of the damping amount. It is also possible to adopt a special configuration for improving the performance.
[0045]
That is, the amount of attenuation (rpm / sec) is set according to the water temperature as shown in FIG. 7, and at this time, the minimum value a of the amount of attenuation (rpm / sec) does not change according to the water temperature. As a result, as shown in FIG. 8, the minimum value "a" of the damping amount (rpm / sec) is changed from the first target engine speed NSET1 to the second target engine speed NSET with the damping amount corresponding to the engine coolant temperature. This is the skip amount S when performing the attenuation control up to.
[0046]
Then, when the damping control is performed from the first target engine speed NSET1 to the second target engine speed NSET with the damping amount, the skip amount S for the minimum value a of the damping amount (rpm / sec) is reduced by the skip amount S. The first target engine speed NSET1 can be shifted to the second target engine speed side NSET, that is, reduced, and then the damping control can be performed to the second target engine speed NSET with an amount of attenuation corresponding to the engine coolant temperature. Therefore, control response can be improved, which is practically advantageous.
[0047]
【The invention's effect】
As described above in detail, according to the present invention, the throttle valve is provided in the intake passage of the engine, the bypass passage that bypasses the upstream side and the downstream side of the throttle valve is provided, and the air flow rate of the bypass passage is adjusted in the bypass passage. In the engine speed control device for controlling the idle control valve so as to provide an idle control valve capable of detecting an engine cooling water temperature and an engine water temperature detecting means capable of detecting an engine cooling water temperature and to set the idling speed to the target engine speed, Thereafter, a first target engine speed corresponding to the engine cooling water temperature is set, and the first target engine speed is held and controlled for a time corresponding to the engine cooling water temperature. Detected and the damping control is performed to the second target engine speed with the damping amount corresponding to the engine cooling water temperature. The target engine speed is set according to the temperature of the engine cooling water during post-warm-up, enabling stable combustion of the engine, preventing misfiring and improving drivability defects caused by engine vibration. As a result, the amount of exhaust gas emission can be reduced.
[Brief description of the drawings]
FIG. 1 is a flowchart for controlling the rotation speed of an engine according to an embodiment of the present invention.
FIG. 2 is a schematic configuration diagram of an engine speed control device.
FIG. 3 shows an engine coolant temperature (also called “water temperature”) (degrees) and a target engine speed (also called “target speed”) for setting first and second target engine speeds NSET1 and NSET. It is a figure which shows the relationship with (rpm).
FIG. 4 is a diagram showing a relationship between an engine cooling water temperature (also referred to as “water temperature”) (degrees) and a holding time (sec) for setting a holding time T1.
FIG. 5 is a diagram showing a relationship between an engine cooling water temperature (also referred to as “water temperature”) (degrees) and an attenuation amount (rpm / sec) for setting an attenuation amount.
FIG. 6 is a time chart of an engine speed behavior from a cold start.
FIG. 7 shows a relationship between an engine cooling water temperature (also referred to as “water temperature”) (degrees) and an attenuation amount (rpm / sec) for setting an attenuation amount according to another first embodiment of the present invention. FIG.
FIG. 8 is a time chart of an engine speed behavior from a cold start.
[Explanation of symbols]
2 Engine 4 Intake passage 6 Exhaust passage 12 Air cleaner 14 Intake temperature sensor 18 Throttle valve 20 Throttle opening sensor 22 Bypass passage 24 Idle control valve (also called “idle air control valve”)
34 fuel injection valve 38 fuel tank 52 pressure sensor 56 canister 58 EGR control means 66 control means (also referred to as “ECM”)
74 Water temperature sensor

Claims (2)

A throttle valve is provided in an intake passage of the engine, a bypass passage is provided for bypassing an upstream side and a downstream side of the throttle valve, and an idle control valve capable of adjusting an air flow rate in the bypass passage is provided in the bypass passage. In the engine speed control device for controlling the idle control valve so that the idling speed becomes equal to the target engine speed, the engine speed control device according to the engine cooling water temperature after starting the engine is provided. After the target engine speed is set and the first target engine speed is held and controlled for a time corresponding to the engine coolant temperature, the engine coolant temperature at the end of the hold control is detected, and the damping according to the engine coolant temperature is detected. Engine speed control apparatus for damping control to a second target engine speed based on the amount of rotation. . The engine speed control device according to claim 1, wherein the second target engine speed is a value corresponding to an engine coolant temperature.

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