JP6159677B2 - engine - Google Patents

Description

  The present invention relates to an engine, and more particularly to an engine that can suppress the generation of white smoke.

Conventionally, there is an engine provided with an EGR device (for example, see Patent Document 1).
According to this type of engine, there is an advantage that the exhaust gas is recirculated by the EGR device, the maximum combustion temperature is lowered, and NOx can be reduced.

  In this type of engine, the EGR device is controlled only for the purpose of reducing NOx.

JP-A-5-18323 (see FIG. 1)

<Problem> White smoke may be generated.
In the conventional engine, since the EGR device is controlled only for the purpose of reducing NOx, incomplete combustion may occur and white smoke may be generated due to an excessive EGR rate. In particular, when operating at a high altitude, such a problem becomes apparent because the oxygen concentration in the air decreases.

  The subject of this invention is providing the engine which can suppress generation | occurrence | production of white smoke.

  As a result of research, the inventors of the present invention have found that the generation of white smoke can be suppressed by adjusting the opening degree of the EGR valve and the fuel supply amount with the excess air ratio as a control target. Invented.

Invention specific matters of the invention according to claim 1 are as follows.
As illustrated in FIG. 1, a control device (1), an intake flow sensor (2), an atmospheric pressure sensor (3), an EGR device (4), and a fuel supply device (5) are provided.
As illustrated in FIG. 2, the control device (1) calculates the actual excess air ratio based on the intake air flow rate and the atmospheric pressure (S5), and the actual excess air ratio is less than the target excess air ratio. When the EGR valve (4a) is not fully closed, the EGR valve opening is corrected to the closed side (S9), and after the EGR valve (4a) is fully closed , the target fuel supply amount is reduced. An engine that is configured to be corrected (S10).

(Invention of Claim 1)
The invention according to claim 1 has the following effects.
<Effect> The generation of white smoke can be suppressed. As illustrated in FIG. 2, the control device (1) calculates the actual excess air ratio based on the intake air flow rate and the atmospheric pressure (S5), and the target air When the actual excess air ratio is insufficient with respect to the excess ratio, the EGR valve opening is corrected to the closed side (S9), and when the EGR valve (4a) is fully closed, the target fuel supply is performed. Since the amount is corrected to be reduced (S10), it is possible to prevent an excessive EGR rate or incomplete combustion due to an excessive fuel injection amount, and to suppress the generation of white smoke. In addition, the oxygen concentration in the air decreases at high altitudes, but since the actual excess air ratio is calculated based on the intake flow rate and atmospheric pressure, the generation of white smoke can be suppressed even when operating at high altitudes. .

It is a mimetic diagram of an engine concerning an embodiment of the present invention. It is a flowchart of control of the engine of FIG.

  FIGS. 1 to 2 are views for explaining an engine according to an embodiment of the present invention. In this embodiment, a vertical in-line four-cylinder diesel engine will be described.

  As shown in FIG. 1, this engine includes four cylinders (19) and a cylinder head (9). Is fitted with an exhaust manifold (11). A flywheel (12) is disposed at the rear of a cylinder block (not shown) provided with the cylinder (8).

The configuration of the fuel supply device (5) is as follows.
As shown in FIG. 1, the cylinder head (9) is provided with an injector (13) for each cylinder (8), and each injector (13) is connected to a common rail (14). The fuel (20) in the fuel tank (16) is pumped to the common rail (14) via the fuel supply pump (15). The electromagnetic valve of each injector (13) is connected to the control device (1), the valve opening timing and the valve opening period are controlled by a control signal from the control device (1), and a predetermined amount of fuel (at a predetermined timing) 20) is injected into the combustion chamber (6).

As shown in FIG. 1, a rotation speed sensor (21) and a speed control sensor (22) are connected to the control device (1), and the set rotation speed of the engine, the deviation between the actual rotation speed and the set rotation speed, and Thus, the fuel injection amount is adjusted.
The control device (1) is an engine ECU. The engine ECU is an abbreviation for engine electronic control unit and is a microcomputer.
An intake flow rate sensor (18) is arranged in the intake passage (17) for supplying intake air to the intake manifold (10).
An atmospheric pressure sensor (3) is connected to the control device (1).

As shown in FIG. 1, the engine includes a control device (1), an intake flow rate sensor (2), an atmospheric pressure sensor (3), an EGR device (4), and a fuel supply device (5).
As shown in FIG. 2, in this engine, the actual excess air ratio is calculated (S5) based on the intake flow rate and the atmospheric pressure by the control device (1), and the actual excess air ratio is smaller than the target excess air ratio. If the intake is insufficient, the EGR valve opening is corrected to the closed side (S9), and if the EGR valve (4a) is fully closed, the target fuel supply amount is corrected to the reduced side (S10). It is comprised so that.
That is, the control device (1) calculates the actual excess air ratio based on the intake air flow rate and the atmospheric pressure (S5), and the actual excess air ratio is insufficient with respect to the target excess air ratio, and the EGR valve (4a). Is not fully closed, the EGR valve opening is corrected to the closed side (S9), and after the EGR valve (4a) is fully closed, the target fuel supply amount is corrected to the reduced side (S10). It is configured as follows.

As shown in FIG. 1, the EGR device (4) is provided between an exhaust manifold (11) and an intake manifold (10), and an EGR cooler (4c) and an EGR valve (4a) are provided in the middle of the EGR passage (4b). ). The opening degree of the EGR valve (4a) is adjusted by the control of the control device (1), and the EGR rate is set.

The flow of control by the control device (1) is as follows.
In step (S1), the throttle opening and the actual rotational speed are read. In step (S2), the target fuel injection amount and the target air excess are determined based on the deviation between the target rotational speed based on the throttle opening and the actual rotational speed. The rate and the target EGR valve opening are calculated. In step (S3), the EGR valve opening is adjusted. In step (S4), the intake air flow rate and the atmospheric pressure are read. In step (S5), the intake air flow rate is increased. The actual excess air ratio is calculated based on the oxygen concentration of the air due to the atmospheric pressure. In step (S6), it is determined whether or not the actual excess air ratio is insufficient for the target air excess ratio.

  If the determination in step (S6) is negative, fuel injection is performed in step (S7), and the process returns to step (S1). If the determination in step (S6) is affirmative, it is determined in step (S8) whether or not the EGR valve (4a) is fully opened. If the determination in step (S8) is negative, the EGR valve opening is corrected to the valve closing side in step (S9), and the process returns to step (S4). If the determination in step (S8) is affirmative, the target fuel injection amount is corrected to the decrease side in step (S10), and the process returns to step (S4).

(1) Control device
(2) Intake flow sensor
(3) Atmospheric pressure sensor
(4) EGR device
(4a) EGR valve
(5) Fuel supply device
(S5) Actual excess air rate is calculated
(S9) EGR valve opening is corrected to the valve closing side
(S10) Target fuel supply is corrected to decrease

Claims (1)

A control device (1), an intake air flow sensor (2), an atmospheric pressure sensor (3), an EGR device (4), and a fuel supply device (5);
The control device (1) calculates the actual excess air ratio based on the intake air flow rate and the atmospheric pressure (S5). The actual excess air ratio is insufficient for the intake air relative to the target excess air ratio , and the EGR valve (4a) If it is not closed, the EGR valve opening is corrected to the closed side (S9), and after the EGR valve (4a) is fully closed , the target fuel supply amount is corrected to the reduced side (S10). An engine characterized by being configured.

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