JP2015161178A - Control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for an internal combustion engine, which can suppress the generation of smoke without deteriorating the fuel consumption at a starting time.SOLUTION: A control device is characterized by comprising: a fuel injection device 20 for feeding a fuel to an internal combustion engine 1; a smoke detecting device for detecting that a smoke arises in the exhaust gas of the internal combustion engine 1; and a fuel control device 20 for dividing and injecting the fuel on condition that the smoke arises in the exhaust gas before the warming-up completion of the internal combustion engine 1, and for raising the pressure of the fuel on condition that smoke occurs in the exhaust gas after the completion of the warming-up of the internal combustion engine 1.

Description

  The present invention relates to an internal combustion engine control device, and more particularly to smoke suppression control executed by an internal combustion engine control device.

An internal combustion engine may emit smoke (white smoke) when fuel is injected when it is cold. This is due to incomplete combustion of the fuel because the temperature of the combustion chamber has not risen sufficiently.
Conventionally, in order to solve such a smoke problem, the fuel is pressurized with a pump and stored in a high pressure accumulator, and when the internal combustion engine is at a low temperature, the fuel of the high pressure accumulator is used for starting. An accumulator fuel injection control device is disclosed (Patent Document 1).
A fuel injection control device for a diesel engine that divides and injects fuel is disclosed. According to this control device, the ECU (electronic control unit) sets the fuel injection amount at the smoke limit point at which the smoke concentration rapidly increases, and when the injection amount exceeds the injection amount at the smoke limit point, the fuel at the smoke limit point The main injection is performed with the injection amount, and the excess is controlled to be after injection. Thereby, it is supposed that the control device can suppress the occurrence of smoke (Patent Document 2).
A sensor for detecting that exhaust gas contains smoke is disclosed in Patent Document 3. The sensor of Patent Document 3 detects the amount of smoke based on the current value of the induced current flowing in the electromagnetic coil by utilizing the property of soot in the exhaust gas as a diamagnetic substance.

JP 2000-234551 A Japanese Patent No. 2002-364437 JP-A-1-20442

  However, when the internal combustion engine is cold and the fuel is injected at a high pressure, the fuel tends to adhere to the wall surface of the cylinder and hinder volatilization. For this reason, in order to ensure sufficient fuel in the cylinder, the fuel injection device has to inject extra fuel by an amount that is prevented from volatilizing, and there is a problem that fuel efficiency at the time of starting deteriorates.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a control device for an internal combustion engine that can suppress the generation of smoke without deteriorating fuel consumption at the time of starting.

  The present invention relates to a fuel injection device that supplies fuel to an internal combustion engine, a smoke detection device that detects the occurrence of smoke in the exhaust gas of the internal combustion engine, and smoke that occurs in the exhaust gas before the warm-up of the internal combustion engine is completed. A fuel control device for increasing the pressure of the fuel on condition that the fuel is divided and injected and smoke is generated in the exhaust gas after the warm-up of the internal combustion engine is completed. To do.

In the present invention, when smoke is generated in the exhaust gas, the fuel control device performs divided injection without increasing the pressure of the fuel if the internal combustion engine is cold, and becomes high after the warm-up is completed. Switch as follows.
For this reason, according to the present invention, it becomes difficult for the fuel to adhere to the wall surface of the cylinder when it is cold, and it is not necessary to inject extra fuel at the time of starting. The fuel control device controls the fuel pressure to be high if smoke still occurs after the internal combustion engine has warmed up, so the split injection did not solve the cold during cold. Even in this case, smoke suppression is achieved early.

FIG. 1 is a system configuration diagram of a control device for an internal combustion engine. (Example). FIG. 2 is a flowchart of the smoke suppression control of the control device. (Example)

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

1 and 2 show an embodiment of the present invention. In FIG. 1, the internal combustion engine 1 includes a plurality of cylinders, for example, four cylinders 2, and an air cleaner 3, an intake pipe 4, a throttle body 5, a surge tank 6, and an intake manifold 7 are sequentially connected to each cylinder 2. An intake passage 8 through which intake air to be supplied flows is provided. The throttle body 4 is provided with a throttle valve 9. Further, the internal combustion engine 1 includes an exhaust passage 14 that sequentially connects an exhaust manifold 10, a front exhaust pipe 11, a catalyst 12, and a rear exhaust pipe 13 and through which exhaust gas discharged from each cylinder 2 flows.
The intake manifold 7 includes a fuel injection valve 15 that injects fuel for each cylinder 2 as a fuel injection device that supplies fuel to the internal combustion engine 1. Each fuel injection valve 15 directly injects fuel into each cylinder 2. Therefore, the internal combustion engine 1 is a so-called direct injection internal combustion engine. Each fuel injection valve 15 is connected to a fuel tank 17 by a fuel passage 16. A fuel pump 18 that pumps the fuel in the fuel tank 17 is provided in the middle of the fuel passage 16.
Each fuel injection valve 15 and the fuel pump 18 are connected to a control device 19 of the internal combustion engine 1. The control device 19 includes a fuel control device 20. The fuel control device 20 includes a coolant temperature sensor 21 that detects the coolant temperature of the internal combustion engine 1, an engine speed sensor 22 that detects the engine speed of the internal combustion engine 1, and a throttle opening that detects the throttle opening of the throttle valve 9. A sensor 23 and a smoke sensor 24 as a smoke detection device for detecting that smoke is generated in the exhaust gas of the internal combustion engine 1 are connected.
The fuel control device 20 obtains the amount of fuel to be supplied during one combustion cycle of the internal combustion engine 1 according to the operation state from the detection values input from the sensors 21 to 24, and performs one combustion of the internal combustion engine 1 based on a predetermined condition. The fuel injection timing, the number of divided injections, and the fuel pressure of the determined amount in the cycle are controlled.
The fuel control device 20 detects that the coolant temperature sensor 21 detects the coolant temperature before the completion of warm-up of the internal combustion engine 1 (when cold), and the smoke sensor 24 detects smoke generated in the exhaust gas. The fuel injection valve 15 is controlled so that the determined amount of fuel is divided and injected. In addition, the fuel control device 20 detects that the coolant temperature sensor 21 detects the coolant temperature after the warm-up of the internal combustion engine 1 is completed, and that the smoke sensor 24 detects smoke generated in the exhaust gas. As a condition, the fuel pump 18 is controlled to increase the pressure of the determined amount of fuel.

Next, the operation will be described.
As shown in FIG. 2, the control device 19 of the internal combustion engine 1 starts the smoke suppression control program as shown in FIG. 2 (100), and determines whether the smoke sensor 24 detects smoke (101). ).
If this determination (101) is NO, the program is ended (106). If this determination (101) is YES, it is determined whether or not the warm-up of the internal combustion engine 1 has been completed based on the cooling water temperature detected by the cooling water temperature sensor 21 (102).
When this determination (102) is NO, fuel is dividedly injected (107), and the program is ended (106). If the determination (102) is YES, the pressure of the fuel is increased to a predetermined value (103), and it is determined whether the fuel pressure exceeds a set value (104).
If the fuel pressure exceeds a set value higher than the predetermined value obtained by increasing the pressure (103) and the determination (104) is YES, the fuel is dividedly injected (105) and the program is ended (106). If the pressure of the fuel is a pressure value increased (103) below the set value and the determination (104) is NO, the fuel increased in pressure to a predetermined value is injected and the program is ended (106).

In this way, the control device 19 of the internal combustion engine 1 divides and injects fuel on the condition that smoke is generated in the exhaust gas by the fuel control device 20 before the warm-up of the internal combustion engine 1 is completed. The fuel pressure is increased on the condition that smoke is generated in the exhaust gas after the completion of warm-up.
Thereby, when the smoke is generated in the exhaust gas of the internal combustion engine 1, the control device 19 of the internal combustion engine 1 does not increase the fuel pressure when the internal combustion engine 1 is cold. Split injection is performed, and after the warm-up is completed, the fuel pressure is switched to a high pressure.
For this reason, it becomes difficult for the control device 19 of the internal combustion engine 1 to adhere to the wall surface of the cylinder 2 at the time of cold, and it is not necessary to inject extra fuel at the time of starting. The fuel control device 20 controls the fuel pressure to be high if the smoke is still generated after the internal combustion engine 1 is warmed up. Therefore, in the cold injection, the smoke is solved. Even if not, smoke suppression is achieved early.

  The present invention can suppress the generation of smoke without deteriorating the fuel efficiency at the time of starting, and can be applied to a direct injection type gasoline internal combustion engine or a diesel internal combustion engine.

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Cylinder 3 Air cleaner 4 Intake pipe 5 Throttle body 6 Surge tank 7 Intake manifold 8 Intake passage 9 Throttle valve 10 Exhaust manifold 11 Front exhaust pipe 12 Catalyst 13 Rear exhaust pipe 14 Exhaust passage 15 Fuel injection valve 16 Fuel passage 17 Fuel tank 18 Fuel pump 19 Control device 20 Fuel control device 21 Cooling water temperature sensor 22 Engine speed sensor 23 Throttle opening sensor 24 Smoke sensor

JP 2000-234551 A JP 2002-364437 A JP-A-1-20442

Claims (1)

  A fuel injection device that supplies fuel to the internal combustion engine, a smoke detection device that detects the occurrence of smoke in the exhaust gas of the internal combustion engine, and the condition that smoke is generated in the exhaust gas before completion of warming up of the internal combustion engine An internal combustion engine comprising: a fuel control device for increasing the pressure of the fuel on condition that the fuel is divided and injected and smoke is generated in the exhaust gas after the warm-up of the internal combustion engine is completed. Control device.

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