JP2009024688A - Control device for engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for an engine improving starting performance after stop of the engine. <P>SOLUTION: The control device for an engine has a stop control means stopping supply of fuel when an ignition signal is switched from ON to OFF. The control device has a pressure detection means detecting intake pipe pressure, and an engine speed detection means detecting an engine speed. The control device further has an air volume control means increasing an air volume taken into a combustion chamber compared with that in normal start, when the ignition switch is ON and the intake pipe pressure detected by the pressure detection means exceeds a set value. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an engine control device, and more particularly to an engine control device that performs start-up control in an engine equipped with a bypass air amount control valve (also referred to as “ISC valve”) or an electronically controlled throttle valve.

The engine control device is provided with a bypass passage that bypasses the throttle valve and connects the intake passage of the throttle body and the intake passage of the surge tank, and the bypass air amount control that adjusts the bypass air amount in the middle of the bypass passage Some have a valve.
Some of the engine control devices have a function of electronically controlling the throttle valve by providing a throttle sensor for detecting the throttle opening of the throttle valve.

JP 2000-234530 A

By the way, in the conventional engine control device, when the engine is restarted immediately after the engine is stopped, there are many cases in which a starting failure occurs.
In other words, after the engine is stopped, as shown in FIG. 5, the intake pipe pressure (also referred to as “intake pipe pressure”) is in a negative pressure state that is higher than 50 kPa. Since the intake pipe pressure during cranking becomes a more negative pressure state, there is a disadvantage that even if air is supplied, a sufficient amount of air is not obtained, leading to poor starting.

In addition, in order to prevent a starting failure when an immediate restart is performed after the engine is stopped, a correction amount is simply added to the air amount introduced at the time of a normal start. Although it is possible to prevent defects, there is a disadvantage that the engine speed is excessively increased during normal starting.
At this time, “normal start” means a case where the elapsed time is sufficiently long until restart after engine stop.

  An object of the present invention is to realize an engine control device capable of improving the starting performance after the engine is stopped.

  Accordingly, in order to eliminate the above-described disadvantages, the present invention provides a pressure for detecting an intake pipe pressure in an engine control device having stop control means for stopping fuel supply when an ignition signal is switched from on to off. A detection means and an engine speed detection means for detecting the engine speed, and when the intake pipe pressure detected from the pressure detection means exceeds a set value when the ignition signal is on, it is sucked into the combustion chamber. An air amount control means for increasing the amount of air to be increased from that at the time of normal starting is provided.

As described above in detail, according to the present invention, when the ignition signal is switched from on to off, in the engine control device provided with the stop control means for stopping the fuel supply, the pressure detection for detecting the intake pipe pressure And an engine speed detecting means for detecting the engine speed, and when the intake pipe pressure detected from the pressure detecting means exceeds the set value when the ignition signal is on, the air taken into the combustion chamber An air amount control means is provided for increasing the amount from that at the normal start.
Therefore, since the intake pipe pressure during cranking shifts to the positive pressure side, it is possible to improve the starting performance.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

1 to 4 show an embodiment of the present invention.
In FIG. 2, 1 is an engine mounted on a vehicle (not shown), 2 is a cylinder block, 3 is a cylinder head, 4 is a head cover, 5 is a piston, 6 is a combustion chamber, 7 is an intake port, 8 is an exhaust port, 9 is The intake valve 10 is an exhaust valve.

In the engine 1, an air cleaner 11, an intake pipe 12, a throttle body 13, a surge tank 14, and an intake manifold 15 are sequentially connected as an intake system, and an intake passage 16 communicating with the intake port 7 is provided.
A throttle valve 17 is provided in the intake passage 16 of the throttle body 13.

Further, the engine 1 is provided with an exhaust passage 21 that sequentially connects an exhaust manifold 18, an exhaust pipe 19, and a catalytic converter 20 as an exhaust system, and communicates with the exhaust port 8.
A catalyst 22 is provided in the catalytic converter 20.

The engine 1 is provided with a PCV valve 23 on the head cover 4.
In addition, a first blow-by gas passage 24 that communicates the inside of the head cover 4 and the intake passage 16 of the surge tank 14 via the PCV valve 23 is provided.
Further, a second blow-by gas passage 25 is provided that communicates the inside of the head cover 4 with the intake passage 16 upstream of the throttle body 13.

The engine 1 is provided with a fuel injection valve 26 in the intake passage 16 on the downstream side of the surge tank 14.
The fuel injection valve 26 is connected to a fuel tank 28 through a fuel supply passage 27.
A fuel pump 29 for supplying fuel to the fuel injection valve 26 via the fuel supply passage 27 is provided in the fuel tank 28.
A fuel filter 30 and a pressure regulator 31 for adjusting the fuel pressure are provided in the fuel supply passage 27 in the fuel tank 28.

One end side of the evaporation passage 32 is communicated with the fuel tank 28 via a two-way check valve 33.
The other end side of the evaporation passage 32 communicates with the canister 34.
The canister 34 communicates with one end side of the purge passage 35.
The other end side of the purge passage 35 communicates with the intake passage 16 upstream of the throttle valve 17.

The engine 1 is provided with a bypass passage 36 that bypasses the throttle valve 17 and connects the intake passage 16 of the throttle body 13 and the intake passage 16 of the surge tank 14.
A bypass air amount control valve (also referred to as “ISC valve”) 37 for adjusting the amount of bypass air is provided in the middle of the bypass passage 36.

The engine 1 is provided with an ignition coil 38 that causes a spark plug (not shown) to ignite, a crank angle sensor 39 that functions as engine speed detection means for detecting the crank angle and the engine speed, and the coolant temperature of the engine 1 is provided. A water temperature sensor 40 for detecting the throttle valve 17, a throttle sensor 41 for detecting the throttle opening of the throttle valve 17, a pressure sensor 42 for detecting the intake pipe pressure of the intake passage 16, and a pressure sensor 42 for detecting the intake pipe pressure. An intake air temperature sensor (not shown) for detecting the intake air temperature is provided, and an air-fuel ratio detecting means for detecting the air-fuel ratio is provided in the exhaust passage 21, for example, an O2 sensor 43 for detecting the oxygen concentration in the exhaust gas.
At this time, the pressure sensor 42 is provided in communication with the intake passage 16 upstream of the surge tank 14 and downstream of the throttle valve 17.

The fuel injection valve 26, the fuel pump 29, the bypass air amount control valve 37, the ignition coil 38, the crank angle sensor 39, the water temperature sensor 40, the throttle sensor 41, the pressure sensor 42, the O2 sensor 43 and the intake air temperature sensor are control means. 44.
Reference numeral 45 is a battery connected to the control means 44, and 46 is an ignition key (also referred to as "IG key").

  The control means 44 includes stop control means 47 for stopping the fuel supply by the fuel injection valve 26 when the ignition signal of the ignition key 46 is switched from on to off.

The control means 44 is sucked into the combustion chamber 6 when the intake pipe pressure detected from the pressure sensor 42 as the pressure detection means exceeds the set value when the ignition signal of the ignition key 46 is on. The air amount control means 48 for increasing the air amount to be increased from that at the time of normal starting is provided.
More specifically, for example, a set value XPA1 composed of a numerical value of 50 kPa is set as the intake pipe pressure.
If the intake pipe pressure detected from the pressure sensor 42 exceeds the set value XPA1 when the ignition signal of the ignition key 46 is on, the air amount control means 48 sucks the air into the combustion chamber 6. The air amount to be increased is larger than that at the normal start.
At this time, as shown in FIG. 3, the amount of increase in the air amount is the air amount control means as shown in the black portion of FIG. 48, the correction air amount XISC1 is added.
As a result, the intake pipe pressure during cranking shifts to the positive pressure side, and the starting performance can be improved.
The control for adding the corrected air amount XISC1 by the air amount control means 48 is stopped when the engine speed detected by the crank angle sensor 39 as the engine speed detecting means exceeds a set value XNE1. .
That is, as shown in FIG. 3, when the engine is restarted immediately after the engine is stopped and the control for adding the correction air amount XISC1 is continued by the air amount control means 48, the point b at which the engine speed exceeds the set value XNE1. The air amount control means 48 stops the increase in the air amount.
As a result, when the cranking period ends, the increase in the air amount is stopped immediately and returned to the normal control, so there is no possibility of adversely affecting the control after starting.

  In the case of normal engine start, as shown in FIG. 4, when the ignition signal of the ignition key 46 is on, the intake pipe pressure is 0 kPa, so the intake pipe pressure detected from the pressure sensor 42 is Does not exceed the set value XPA1, and the control for increasing the amount of air sucked into the combustion chamber 6 by the air amount control means 48 is not performed as compared with the normal start.

  Next, the operation will be described along the control flowchart of the engine control device of FIG.

When the control program of the engine control device starts (101), it is determined whether the intake pipe pressure detected from the pressure sensor 42 exceeds the set value XPA1 when the ignition signal of the ignition key 46 is on. Move to (102).
In this determination (102), when the determination (102) is YES, the process proceeds to a process (103) for adding the correction air amount XISC1 to the air amount introduced at normal time.
If the determination (102) is NO, the process proceeds to the end (107) of the control program described later.

Further, after the process (103) of adding the correction air amount XISC1 to the air amount introduced at the normal time, the engine speed detected by the crank angle sensor 39 serving as the engine speed detecting means is a set value XNE1. The process proceeds to determination (104) of whether or not the maximum value is exceeded.
If the determination (104) is YES in this determination (104), the process proceeds to the processing (105) for setting the correction air amount XISC1 to “0”, and the increase in the air amount by the air amount control means 48 is stopped. Thereafter, the process proceeds to the end (107) of the control program.
At this time, if the determination (104) is NO, the routine proceeds to processing (105) for maintaining the corrected air amount XISC1, and the air amount sucked into the combustion chamber 6 by the air amount control means 48 is normally started. Then, the control for increasing the engine speed is continued, and then the process returns to the determination (104) as to whether or not the engine speed detected by the crank angle sensor 39 as the engine speed detecting means exceeds the set value XNE1.

Thereby, when the ignition signal is switched from on to off, in the engine control device provided with the stop control means 47 for stopping the fuel supply, the pressure sensor 42 as the pressure detection means for detecting the intake pipe pressure, the engine A crank angle sensor 39 functioning as an engine speed detecting means for detecting the rotational speed, and an intake pipe pressure detected from the pressure sensor 42 as the pressure detecting means when the ignition signal is on exceeds a set value XPA1 Is provided with an air amount control means 48 for increasing the amount of air sucked into the combustion chamber 6 as compared with the normal starting time.
Therefore, since the intake pipe pressure during cranking shifts to the positive pressure side, it is possible to improve the starting performance.

Further, when the engine speed detected by the crank angle sensor 39 functioning as the engine speed detecting means exceeds the set value XNE1, the increase in the air quantity by the air quantity control means 48 is stopped.
Accordingly, when the cranking period ends, the increase in the air amount is stopped immediately and returned to the normal control, so that the control after starting is not adversely affected.

It is a flowchart for control of the control apparatus of the engine which shows the Example of this invention. It is a system diagram of an engine control device. The time chart after improvement is shown, (a) is a time chart of an ignition (also referred to as “IG”) signal, (b) is a time chart of the intake pipe pressure (also referred to as “intake pipe pressure”), and (c). Is a time chart of the engine speed, (d) is a time chart of the air amount, and (e) is a time chart of the corrected air amount XISC1. A time chart after improvement (normal engine start) is shown, (a) is a time chart of an ignition (also referred to as “IG”) signal, and (b) is an intake pipe pressure (also referred to as “intake pipe pressure”). (C) is a time chart of the engine speed, (d) is a time chart of the air amount, and (e) is a time chart of the corrected air amount XISC1. The time chart before improvement which is the prior art of this invention is shown, (a) is a time chart of an ignition (also referred to as “IG”) signal, and (b) is the intake pipe pressure (also referred to as “intake pipe pressure”). (C) is a time chart of the engine speed, and (d) is a time chart of the air amount.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 6 Combustion chamber 9 Intake valve 10 Exhaust valve 11 Air cleaner 13 Throttle body 14 Surge tank 15 Intake manifold 16 Intake passage 17 Throttle valve 18 Exhaust manifold 20 Catalytic converter 21 Exhaust passage 22 Catalyst 23 PCV valve 26 Fuel injection valve 28 Fuel tank 29 Fuel pump 31 Pressure regulator 32 Evaporation passage 33 2-way check valve 34 Canister 35 Purge passage 36 Bypass passage 37 Bypass air amount control valve (also referred to as “ISC valve”)
38 Ignition coil 39 Crank angle sensor 40 Water temperature sensor 41 Throttle sensor 42 Pressure sensor as pressure detecting means 43 O2 sensor 44 Control means 45 Battery 46 Ignition key (also referred to as “IG key”)
47 Stop control means 48 Air amount control means

Claims (2)

  When the ignition signal is switched from on to off, in an engine control device having a stop control means for stopping the fuel supply, a pressure detection means for detecting the intake pipe pressure and an engine speed detection for detecting the engine speed Air amount control for increasing the amount of air sucked into the combustion chamber more than at the normal start when the intake pipe pressure detected from the pressure detection means exceeds a set value when the ignition signal is on An engine control device comprising means.   2. The engine according to claim 1, wherein when the engine speed detected by the engine speed detection means exceeds a set value, the increase in the air amount by the air amount control means is stopped. Control device.

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