JP2008163860A - Intake device of fuel injection type engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce cost by omitting an idle air volume control device. <P>SOLUTION: This intake device has a throttle body 32 forming a part of an intake passage 31 communicating with a combustion chamber 39 of an engine 20, a throttle valve 33 opening and closing the intake passage 31 of the throttle body 32, a fuel injection valve 37 injecting fuel into the intake passage 31, a fuel supply device for supplying the fuel to the fuel injection valve 37, and an ECU (a control device) 62 controlling a fuel injection quantity injected from the fuel injection valve 37. The throttle body 32 is provided with a bypass passage 40 bypassing the throttle valve 33 and flowing a predetermined quantity of suction air. An idle speed is controlled by the ECU (the control device) 62 in a state of setting an intake flow rate constant by fully closing the throttle valve 33. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention mainly relates to an intake device for a fuel injection type engine in a vehicle such as an automobile or a motorcycle.

  Conventionally, when an engine is cold, there is a lot of mechanical loss of the internal combustion engine, so-called mechanical loss, so it is difficult to ensure the idling speed during cold. Therefore, particularly in a fuel injection type engine, an idle air amount control device for controlling an idle air amount such as an idle speed control valve (hereinafter referred to as “ISC valve”), an auto starter or the like is provided. The idle air amount control device secures the idle rotation speed by increasing the intake air amount during idling when it is cold. Note that there is an ISC valve described in Patent Document 1. Further, there is an auto starter described in Patent Document 2.

JP 2005-351191 A JP-A-8-28355

However, if an idle air amount control device is mounted on a fuel-injected engine, the cost is inevitably increased. Further, the cost increase due to the idle air amount control device is one of the factors hindering the electronically controlled fuel injection (FI) of the motorcycle engine. By the way, it can be considered that the market of motorcycles, etc., accounts for a large proportion of the temperate market when viewed from the whole market. In a warm region, the idle air amount control device is currently mounted on the fuel injection type engine even though the requirement for the idling speed during cold weather is not strict as compared to the cold region.
The problem to be solved by the present invention is to provide an intake device for a fuel injection engine that can reduce the cost by omitting an idle air amount control device.

The above-described problem can be solved by an intake device for a fuel injection engine having the gist of the configuration described in the claims.
That is, according to the intake device for a fuel injection engine according to claim 1 of the claims, a predetermined amount of intake air flows through the bypass passage provided in the throttle body and bypassing the throttle valve. The idling speed is controlled by the control device in a state where the intake flow rate is made constant with the valve fully closed. Thereby, cost can be reduced by omitting idle air amount control devices such as an ISC valve and an auto starter that are conventionally required.

  According to the fuel injection type engine intake device of claim 2, the idling speed is controlled by the control device in a state in which the throttle valve is set to a predetermined opening and the intake air flow rate is made constant. Thereby, cost can be reduced by omitting idle air amount control devices such as an ISC valve and an auto starter that are conventionally required.

  According to the fuel injection engine intake device of claim 3, the control device controls the fuel injection amount of the fuel injection valve based on the warm-up state of the engine and / or the engine speed. . As a result, a stable idle speed can be obtained.

  According to the intake device for a fuel injection engine according to claim 4 of the claims, the control device controls the ignition timing based on the warm-up state of the engine and / or the engine speed. As a result, a stable idle speed can be obtained.

  Next, the best mode for carrying out the present invention will be described with reference to examples.

[Example 1]
A first embodiment of the present invention will be described. This embodiment is applied to a fuel injection engine for a motorcycle. First, an engine system of a fuel injection engine will be described. FIG. 1 is a schematic configuration diagram showing the engine system.
As shown in FIG. 1, an engine system 10 mounted on a vehicle (for example, “two-wheeled vehicle”) includes a fuel tank 12 for storing fuel. A fuel pump 13 disposed in the fuel tank 12 sucks and pressurizes fuel stored in the fuel tank 12 through the fuel filter 14 and supplies the fuel to a fuel injection valve 37 (described later) through the fuel passage 15. To do. The fuel pump 13 is driven and controlled by an ECU 62 (described later). The pressure of the fuel supplied to the fuel injection valve 37 is adjusted to a predetermined pressure by the pressure regulator 17. The fuel tank 12, the fuel pump 13, and the fuel passage 15 constitute a “fuel supply device” in this specification.

  A reciprocating type four-cycle single cylinder engine (simply referred to as “engine”) 20 that is an internal combustion engine is provided with a water temperature sensor 22 that detects the temperature of engine cooling water. Further, the engine 20 is provided with a crank angle sensor 25 for detecting the rotation speed of the crankshaft 24, that is, the engine rotation speed. Detection signals from the water temperature sensor 22 and the crank angle sensor 25 are output to the ECU 62 (described later).

  On the intake side of the engine 20, an intake pipe 30 that communicates with the intake port 28 of the cylinder head 27, a throttle body 32 that communicates with the intake pipe 30 and includes a throttle valve 33, and an air cleaner 35 that communicates with the throttle body 32 are disposed. ing. The intake pipe 30, the throttle body 32, and the air cleaner 35 form a series of intake passages 31 communicating with the combustion chamber 39 of the engine 30, and the throttle body 32 forms a part of the intake passage 31. A fuel injection valve 37 is attached to the intake pipe 30. Further, the throttle valve 33 of the throttle body 32 is opened and closed based on the operation of a predetermined accelerator device (not shown), so that the amount of intake air taken into the combustion chamber 39 of the engine 30 through the intake passage 31 is adjusted. Is done. Further, when the accelerator operation is not performed, that is, when the throttle valve 33 is fully closed, the intake air amount is set to 0 (zero) or almost zero.

  The throttle body 32 is provided with a bypass passage 40 that bypasses the throttle valve 33. The bypass passage 40 is formed as a passage for flowing an intake air amount at which an idling speed necessary for starting the engine 20 can be obtained when the engine 20 is cold (for example, + 20 ° C. to + 30 ° C.). Thus, the throttle body 32 is a throttle body that is not equipped with an idle air amount control device that controls the amount of idle air, such as a conventional ISC valve (see Patent Document 1) and an auto starter (see Patent Document 2). It has become.

  The throttle body 32 is provided with a throttle position sensor 42 for detecting the opening of the throttle valve 33 and an intake pressure sensor 43 for detecting the intake pressure. The air cleaner 35 includes an air cleaner element 45 and an intake air temperature sensor 46 that detects an intake air temperature on the downstream side of the air cleaner element 45, that is, on the clean side. Detection signals from the throttle position sensor 42, the intake pressure sensor 43, and the intake air temperature sensor 46 are output to the ECU 62 (described later).

  An exhaust pipe 49 communicating with the exhaust port 48 of the cylinder head 27 is communicated with the exhaust side of the engine 20. A three-way catalyst 52 for purifying exhaust gas is provided in the exhaust passage 50 in the exhaust pipe 49.

  A spark plug 54 facing the combustion chamber 39 is provided on the cylinder head 27 of the engine 20. The spark plug 54 sparks by receiving an ignition signal output from the ignition coil 55 at each ignition timing by the ECU 62 (described later). As a result, the combustible air-fuel mixture supplied to the combustion chamber 39 is ignited. The spark plug 54 and the ignition coil 55 constitute an ignition device.

  The fuel supplied from the fuel pump 13 to the fuel injection valve 37 through the fuel passage 15 is injected into the intake passage 31 in the intake pipe 30 by the operation of the fuel injection valve 37. Further, air is taken into the intake passage 31 from the outside through an air cleaner element 45 of an air cleaner 35. The air taken into the intake passage 31 and the fuel injected from the fuel injection valve 37 are sucked into the combustion chamber 39 of the engine 20 as a combustible air-fuel mixture, that is, a predetermined air-fuel ratio (A / F) air-fuel mixture. . The combustible air-fuel mixture sucked into the combustion chamber 39 explodes and burns by the spark discharge of the spark plug 54. Along with this, the piston 57 moves and the crankshaft 24 rotates, so that a driving force for running the motorcycle can be obtained. Further, the exhaust gas after combustion is discharged to the outside, that is, into the atmosphere through the exhaust passage 50 in the exhaust pipe 49.

  In addition, the motorcycle equipped with the engine 20 includes a battery 60 as a vehicle power source, an ignition switch 61 for starting the engine 20 when operated by a driver, and an electronic control for controlling various actuators of the engine 20. An apparatus (referred to as “ECU”) 62 is provided. The ECU 62 constitutes a “control device” in this specification.

  The battery 60 is connected to the ECU 62 via the ignition switch 61. Therefore, a main relay 63 that supplies and cuts off electric power from the battery 60 to the ECU 62 is provided between the ignition switch 61 and the ECU 62. The main relay 63 includes a contact point and a coil, and performs an on / off operation using a magnetic force generated in the coil when a current flows through the coil when the ignition switch 61 is turned on. That is, the main relay 63 is turned on when a current is passed through the coil, and is turned off when a current is not passed through the coil. When the main relay 63 is turned on, electric power is supplied from the battery 60 to the ECU 62.

The sensors 22, 25, 42, 43, 46 provided on the engine 20 detect various operating parameters related to the operating state of the engine 20, and are connected to the ECU 62 (described later) 20. Yes. That is, the water temperature sensor 22 detects the temperature (cooling water temperature) of the engine cooling water flowing through the so-called water jacket inside the engine 20 and outputs an electrical signal corresponding to the detected value to the ECU 62. The water temperature sensor 22 corresponds to “warm-up state detection means for detecting the warm-up state of the engine” in the present specification.
The crank angle sensor 25 detects the number of rotations of the crankshaft 24 and outputs an electrical signal corresponding to the detected value to the ECU 62. The crank angle sensor 25 corresponds to “engine speed detecting means for detecting the engine speed” in the present specification.
The throttle position sensor 42 detects the opening degree of the throttle valve 33 and outputs an electric signal corresponding to the detected value to the ECU 62. The throttle position sensor 42 corresponds to “throttle opening detecting means” in this specification.
The intake pressure sensor 43 detects the intake pressure in the intake passage 31 on the downstream side of the throttle valve 33 and outputs an electrical signal corresponding to the detected value to the ECU 62. The intake pressure sensor 43 corresponds to “intake pressure detection means” in this specification.

  The ECU 62 controls the fuel injection valve 37, the ignition coil 55, and the like in order to execute fuel injection control, ignition timing control, and the like based on the electrical signals output from the sensors 22, 25, 42, 43, 46, respectively. Control. Here, the fuel injection control is to control the fuel injection amount by the fuel injection valve 37 and the injection timing thereof according to the operating state of the engine 20. The ignition timing control is to control the ignition timing by the spark plug 54 by controlling the ignition coil 55 in accordance with the operating state of the engine 20.

  As is well known, the ECU 62 includes a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), a backup RAM, an external input circuit, an external output circuit, and the like. The ECU 62 constitutes a logical operation circuit formed by connecting a CPU, a ROM, a RAM, a backup RAM, an external input circuit, an external output circuit, and the like through a data bus. The ROM stores a predetermined control program related to various controls of the engine 20 in advance. The RAM temporarily stores the calculation results of the CPU. The backup RAM stores data stored in advance. Further, the CPU executes the various controls described above according to a predetermined control program based on the detection signals of the sensors 22, 25, 42, 43, and 46 that are input via the input circuit. The ECU 62 constitutes a “control device” in this specification. Further, the throttle body 32, the throttle valve 33, the fuel injection valve 37, the fuel supply device (the fuel tank 12, the fuel pump 13, and the fuel passage 15) and the ECU 62 constitute an “intake device” in this specification.

  Next, of the various controls executed by the ECU 20 in the engine system 10 (see FIG. 1), the processing content related to the idle speed control at the start of the engine 20 will be described. FIG. 2 is a flowchart showing a program relating to idle speed control at engine start. The program according to this flowchart is a timer interruption process. The ECU 20 determines whether or not the engine 20 is in an idle operation state based on signals from various sensors 22, 25, 42, 43, and 46, and performs an idle operation. Starts when it is determined that it is in a state.

  First, in step 100, an initial value of delay time (for example, 1 s) is set in the first delay counter A, and then the process proceeds to step 102. Next, in step 102, it is determined whether or not the first delay counter A is 0 (zero). Here, since 1 s has just been set in the first delay counter A in step 102, the process proceeds to step 104. Next, in step 104, the ignition timing map is read, and based on the signal from the water temperature sensor 22, the engine temperature (engine cooling water temperature), that is, the ignition timing corresponding to the warm-up state is set. .

  Next, in step 106, the fuel injection amount correction value map is read, and the injection amount correction value corresponding to the engine temperature (engine cooling water temperature), that is, the warm-up state, is set based on the signal from the water temperature sensor 22. After that, the process proceeds to step 108. Next, in step 108, 0.2s is subtracted from the first delay counter A, and then the process returns to step 102. In this way, each time Steps 102 to 108 are repeated, the counter value obtained by subtracting 0.2 s is set to the first delay counter A, and finally 0 (zero) is set to the first delay counter A. When set, in step 102, the first delay counter A is determined to be 0 (zero), so that the idle speed feedback control is performed, and thus the process proceeds to step 110.

  Next, in step 110, an initial value (for example, 10 s) of the delay time is set in the second delay counter B, and then the process proceeds to step 112. Next, in step 112, it is determined whether or not the second delay counter B is greater than 0 (zero). If the second delay counter B is greater than 0, the process proceeds to step 113. Next, in step 113, 1s is subtracted from the second delay counter B, and then the process returns to step 112. In this way, each time Steps 112 and 113 are repeated, the counter value obtained by subtracting 1 s at a time is set in the second delay counter B, and finally 0 (zero) is set in the second delay counter B. Then, in step 112, when it is determined that the second delay counter B is smaller than 0, the process proceeds to step 114. That is, the process proceeds to step 114 at a rate of once every 10 seconds.

Next, in step 114, the correction value map of the fuel injection amount is read, and the correction value of the injection amount corresponding to the engine temperature (engine cooling water temperature), that is, the warm-up state is set based on the signal from the water temperature sensor 22. After that, the process proceeds to step 116.
Next, in step 116, the target rotational speed map is read, and based on the signal from the water temperature sensor 22, the engine temperature (engine cooling water temperature), that is, the target rotational speed corresponding to the warm-up state is read. Proceed to

Next, in step 118, the target rotational speed read in step 116 is compared with the current idle rotational speed. If the current idle speed is higher than the target speed, the process proceeds to step 120. If the current idle speed is lower than the target speed, the process proceeds to step 122. In step 120, the ignition timing is retarded (for example, delayed by 1 ° CA) to reduce the idling engine speed to the target engine speed while preventing the idling engine speed from being excessively increased. Return to 110. In step 122, the ignition timing is advanced (for example, advanced by 1 ° CA) to increase the idle rotational speed to the target rotational speed, and then returns to step 110.
Thus, by performing idle speed feedback control every 10 seconds, a more stable idle speed can be maintained.

  Further, when the ECU 20 determines that the engine 20 is not in an idling operation state based on signals from the various sensors 22, 25, 42, 43, and 46, the program executes the first delay counter A and the second delay counter. Reset B and exit.

FIG. 3 is a time chart concerning the ignition timing, the intake air amount, and the engine speed. In FIG. 3, the horizontal axis indicates time (minutes), and the vertical axis indicates the ignition timing, the intake air amount, and the engine speed in order from top to bottom. Characteristic lines A (1) to (3) indicate characteristics based on experimental data of the fuel injection type engine 20 according to the present embodiment, and characteristic lines B (1) to (3) indicate characteristics of a conventional example including an ISC valve. The characteristic by the experimental data concerning a fuel injection type engine is shown.
[Intake air volume]
The characteristic line B (2) is maximized immediately after the engine is started by the operation of the ISC valve, and thereafter gradually decreases to a predetermined intake air amount, whereas the characteristic line A (2) causes the throttle valve 33 to It can be seen that the intake flow rate is fixed to a predetermined intake air amount flowing through the bypass passage 40 by fully closing.
[Engine RPM]
The characteristic line B (3) is gradually decreased to a predetermined idle speed after reaching a high speed exceeding the idle speed immediately after the engine is started by the operation of the ISC valve. It can be seen that (3) maintains the idling speed continuously after reaching the idling speed with a slight delay immediately after the start of the engine 20 compared to the characteristic line B (3).
[Ignition timing]
The characteristic line B (1) continuously maintains a predetermined ignition timing after the engine is started, whereas the characteristic line A (1) is slowly retarded from the advanced state by the ignition timing control by the ECU 62. Furthermore, it is retarded from the top dead center (TDC). As a result, the engine speed is continuously maintained at the idle speed (see characteristic line A (3)).

  According to the intake device of the fuel injection type engine 20 described above, since a predetermined amount of intake air flows through the bypass passage 40 provided in the throttle body 32 and bypassing the throttle valve 33, the throttle valve 33 is fully closed and the intake air is discharged. With the flow rate fixed, the ECU 62 controls the idle speed. Thereby, cost can be reduced by omitting idle air amount control devices such as an ISC valve and an auto starter that are conventionally required. This is suitable as an intake device for a fuel injection engine 20 for a vehicle such as a two-wheeled vehicle marketed in a warm region.

  Further, the ECU 62 controls the fuel injection amount of the fuel injection valve 37 based on the warm-up state due to the engine coolant temperature (see step 106 in FIG. 3). As a result, a stable idle speed can be obtained. The ECU 62 may control the fuel injection amount of the fuel injection valve 37 based on the warm-up state, and may control the fuel injection amount of the fuel injection valve 37 based on the warm-up state and / or the engine speed. Good.

  Further, the ECU (control device) 62 controls the ignition timing based on the warm-up state due to the engine coolant temperature (see step 104 in FIG. 3). As a result, a stable idle speed can be obtained. Note that the ECU 62 may control the ignition timing based on the warm-up state and / or the engine speed, in addition to controlling the ignition timing based on the warm-up state.

  The calculation of the basic injection amount of the fuel injection amount of the fuel injection valve 37 can be performed by either the α-N method control or the DJ method control. As is well known, the α-N method is a method for determining the basic injection amount by calculating the intake air amount based on the relationship between the throttle opening and the engine speed. The DJ system is a system that determines the basic injection amount by calculating the intake air amount based on the relationship between the intake pressure (intake negative pressure) and the engine speed. In addition, the α-N system is easily affected by dirt adhering to the passage wall surface of the intake passage. However, when the bypass passage 40 is provided, the influence of the dirt can be reduced. N-type control can also be employed.

  As shown in FIG. 4, the throttle body 32 in the engine system 10 (see FIG. 1) in the first embodiment can be changed to a throttle body 321 in which the intake pressure sensor 43 is omitted.

[Example 2]
A second embodiment of the present invention will be described. In the present embodiment, a part of the engine system 10 (see FIG. 1) of the first embodiment is changed. Therefore, the changed portion will be described in detail, and redundant description will be omitted. FIG. 5 is a schematic configuration diagram showing the engine system.
As shown in FIG. 5, in this embodiment, the throttle body 32 in the engine system (see FIG. 1) in the first embodiment is changed to a throttle body 322 in which the bypass passage 40 is omitted.

  In the present embodiment, the ECU 62 controls the idle speed while the throttle valve 33 is set to a predetermined opening and the intake air flow rate is made constant. Here, the predetermined opening of the throttle valve 33 is, for example, an opening at which an intake air intake amount corresponding to the intake air intake amount flowing through the bypass passage 40 in the first embodiment is obtained. Therefore, also according to the present embodiment, the same actions and effects as those of the first embodiment can be obtained. Further, by omitting the bypass passage 40 together with the idle air amount control device, the configuration can be further simplified and the cost can be reduced.

  The present invention is not limited to the above-described embodiments, and modifications can be made without departing from the gist of the present invention. For example, the present invention can be applied not only to a single cylinder engine but also to a multi-cylinder engine. The present invention can be applied not only to a fuel injection engine for a two-wheeled vehicle but also to a fuel injection engine for a four-wheeled vehicle. The engine warm-up state can also be detected by detecting the temperature of the engine cooling water, the temperature of the oil such as engine oil, the viscosity, the temperature of the engine, and the like.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram which shows the engine system concerning Example 1 of this invention. It is a flowchart which shows the program concerning idle speed control at the time of engine starting. It is a time chart concerning ignition timing, intake air quantity, and engine speed. It is a schematic block diagram which shows the engine system concerning the example of a change of Example 1 of this invention. It is a schematic block diagram which shows the engine system concerning Example 2 of this invention.

Explanation of symbols

20 Engine 31 Intake Passage 32 Throttle Body 33 Throttle Valve 37 Fuel Injection Valve 39 Combustion Chamber 40 Bypass Passage 62 ECU (Control Device)
321 Throttle body 322 Throttle body

Claims (4)

A throttle body that forms part of an intake passage communicating with the combustion chamber of the engine;
A throttle valve for opening and closing the intake passage of the throttle body;
A fuel injection valve for injecting fuel into the intake passage;
A fuel supply device for supplying fuel to the fuel injection valve;
A fuel injection engine intake device comprising: a control device that controls a fuel injection amount injected from the fuel injection valve;
The throttle body is provided with a bypass passage that bypasses the throttle valve and through which a predetermined amount of intake air flows.
An intake device for a fuel injection type engine, wherein the control device controls the idling speed in a state where the throttle valve is fully closed and the intake flow rate is made constant. A throttle body that forms part of an intake passage communicating with the combustion chamber of the engine;
A throttle valve for opening and closing the intake passage of the throttle body;
A fuel injection valve for injecting fuel into the intake passage;
A fuel supply device for supplying fuel to the fuel injection valve;
A fuel injection engine intake device comprising: a control device that controls a fuel injection amount injected from the fuel injection valve;
An intake device for a fuel injection type engine, wherein the control device controls the idling speed in a state where the throttle valve is set to a predetermined opening and the intake flow rate is made constant. An intake device for a fuel injection engine according to claim 1 or 2,
An intake device for a fuel injection type engine, wherein the control device is configured to control a fuel injection amount of the fuel injection valve based on a warm-up state of the engine and / or an engine speed. An intake device for a fuel injection engine according to any one of claims 1 to 3,
An intake device for a fuel injection engine, wherein the control device is configured to control an ignition timing based on a warm-up state of the engine and / or an engine speed.

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