JP7011008B2 - Intake meter and engine - Google Patents

Description

The present invention relates to an intake air amount measuring device and an engine for measuring the flow rate of intake air flowing through an intake air pipe of an engine.

Patent Document 1 discloses an intake control device for an engine including a MAF sensor. The MAF sensor described in Patent Document 1 is provided in the intake pipe on the upstream side of the turbocharger, and detects the flow rate of the intake air flowing through the intake pipe. In an internal combustion engine such as a diesel engine, as in the engine disclosed in Patent Document 1, for example, a hot wire type intake amount sensor (MAF sensor) for detecting the intake amount of air (intake) flowing through an intake pipe is used in an internal combustion engine such as a diesel engine. Is provided in the intake pipe. The amount of intake air is the flow rate of air (intake air) flowing through the intake pipe, and is also called an intake air flow rate or MAF.

However, there is a problem that the output characteristic of the intake air amount sensor provided in the intake air pipe depends on the shape of the intake air system (for example, the intake air pipe) on the upstream side of the intake air amount sensor. The intake system on the upstream side of the intake amount sensor differs depending on the application installed in, for example, an industrial diesel engine. Therefore, the calibration work of the intake air amount sensor is required for each application mounted on the engine, which is complicated.

Japanese Unexamined Patent Publication No. 2010-285957

The present invention has been made to solve the above problems, and it is possible to suppress the measurement result of the flow rate of the intake air flowing through the intake pipe from depending on the shape of the intake pipe and to stably measure the flow rate of the intake air. It is an object of the present invention to provide an intake air amount measuring device and an engine capable.

The subject is an intake air amount measuring device for measuring the flow rate of intake air of an engine having three or more cylinders in series, the intake air distribution means for distributing the intake air to the cylinders of the engine, and the temperature of the intake air. A calculation for calculating the flow rate based on the temperature detecting means for detecting, the pressure detecting means for detecting the pressure of the intake air, the temperature transmitted from the temperature detecting means, and the pressure transmitted from the pressure detecting means. The intake air distribution means is provided with a section, and the longitudinal direction of the intake air distribution means is along the direction in which the cylinders of the engine are lined up. Is the inside of the intake air distribution means, the first branch portion of the intake air distribution means connected to the first cylinder of the engine provided at the position farthest from the one end in the longitudinal direction, and in the longitudinal direction. The temperature of the intake air located between the first cylinder and the second branch of the intake air distribution means connected to the second cylinder of the engine provided at a position far from the one end is detected. The pressure detecting means is in the longitudinal direction of the intake air at the position between the first branch portion and the second branch portion with respect to the intake air whose temperature is detected by the temperature detecting means. The solution is solved by the intake air amount measuring device according to the present invention, which detects the pressure of the intake air located near one end and is taken out and transmitted through the intake air pressure acquisition path .

According to the intake air amount measuring device according to the present invention, the longitudinal direction of the intake air distribution means for distributing the intake air to the cylinders of the engine is along the direction in which the cylinders of the engine are lined up. The intake air of the engine flows into the intake air distribution means from one end in the longitudinal direction of the intake air distribution means. Then, the calculation unit calculates the flow rate of the intake air based on the temperature of the intake air transmitted from the temperature detecting means and the pressure of the intake air transmitted from the pressure detecting means. The temperature detecting means detects the temperature of the intake air located between the first branch portion of the intake air distribution means and the second branch portion of the intake air distribution means. The first branch portion is connected to the first cylinder of the engine provided at the position farthest from one end of the intake air distribution means in the longitudinal direction of the intake air distribution means. The second branch portion is connected to the second cylinder of the engine provided at a position far from one end of the intake air distribution means next to the first cylinder of the engine in the longitudinal direction of the intake air distribution means. As described above, the temperature detecting means detects the temperature of the intake air at a position where the intake air flow is relatively stable in the region in the intake air distribution means. Then, the calculation unit determines the temperature of the intake air transmitted from the temperature detecting means and the pressure of the intake air transmitted from the pressure detecting means, regardless of the intake amount sensor (MAF sensor) that detects the flow rate of the intake air flowing through the intake pipe. The flow rate of intake air is calculated based on. As a result, the intake air amount measuring device according to the present invention can suppress the measurement result of the flow rate of the intake air flowing through the intake pipe from depending on the shape of the intake pipe, and can stably measure the flow rate of the intake air.

According to the intake air amount measuring device according to the present invention, the pressure detecting means detects the pressure of the intake air at a position where the intake air flow is relatively stable in the region in the intake air distribution means, similarly to the temperature detecting means. Then, the calculation unit calculates the flow rate of the intake air based on the temperature of the intake air transmitted from the temperature detecting means and the pressure of the intake air transmitted from the pressure detecting means, regardless of the intake amount sensor (MAF sensor). .. As a result, the intake air amount measuring device according to the present invention can further suppress that the measurement result of the flow rate of the intake air flowing through the intake pipe depends on the shape of the intake pipe, and can measure the flow rate of the intake air more stably. can.

According to the intake air amount measuring device according to the present invention, the pressure detecting means measures the pressure of the intake air located closer to one end of the intake air distribution means in the longitudinal direction of the intake air distribution means than the intake air whose temperature is detected by the temperature detecting means. To detect. Therefore, the pressure detecting means is not the intake air in the position where the flow is disturbed by, for example, the probe of the temperature detecting means installed in the intake air distribution means, but the intake air in the more stable position before the flow is disturbed. Detect pressure. Therefore, the pressure detecting means can detect the pressure of the intake air more stably. As a result, the intake air amount measuring device according to the present invention can further suppress that the measurement result of the flow rate of the intake air flowing through the intake pipe depends on the shape of the intake pipe, and can measure the flow rate of the intake air more stably. can.

The intake air amount measuring device according to the present invention preferably detects the differential pressure between the exhaust recirculation means for recirculating the exhaust of the engine and the exhaust pressure flowing through the exhaust recirculation means and the intake air flowing through the intake air distribution means. The calculation unit further includes a differential pressure detecting means transmitted to the calculation unit, the calculation unit further calculates the flow rate based on the differential pressure transmitted from the differential pressure detecting means, and the differential pressure detecting means calculates the flow rate. Of the intake air at the position between the first branch portion and the second branch portion, the intake air is located closer to one end in the longitudinal direction than the intake air whose temperature is detected by the temperature detecting means. It is characterized in that the differential pressure is detected based on the pressure taken out and transmitted through the intake pressure acquisition path, which is the pressure of the intake air .

According to the intake air amount measuring device according to the present invention, the intake air amount measuring device further includes an exhaust recirculation means for recirculating the exhaust of the engine and a differential pressure detecting means. The calculation unit further calculates the flow rate of the intake air based on the differential pressure between the exhaust gas and the intake air transmitted from the differential pressure detecting means. The differential pressure detecting means detects the differential pressure between the exhaust gas flowing through the exhaust recirculation means and the intake air flowing through the intake air distribution means, and transmits the differential pressure to the calculation unit. Here, the differential pressure detecting means detects the differential pressure between the exhaust gas and the intake air based on the pressure of the intake air located between the first branch portion and the second branch portion. That is, the position where the pressure of the intake air is detected by the differential pressure detecting means is the same as the position where the pressure of the intake air is detected by the pressure detecting means, that is , the position between the first branch portion and the second branch portion. Thereby, when the exhaust recirculation means for recirculating the exhaust of the engine is provided, the intake air amount measuring device according to the present invention can improve the calculation accuracy of the flow rate of the intake air flowing through the intake pipe.

According to the intake air amount measuring device according to the present invention, the differential pressure detecting means is located closer to one end of the intake air distribution means in the longitudinal direction of the intake air distribution means than the intake air whose temperature is detected by the temperature detection means. The differential pressure between the exhaust and the intake is detected based on. Therefore, the differential pressure detecting means is not the intake air in the position where the flow is disturbed by, for example, the probe of the temperature detecting means installed in the intake air distribution means, but the intake air in a more stable position before the flow is disturbed. The differential pressure between the exhaust and the intake is detected based on the pressure of. Therefore, the differential pressure detecting means can more stably detect the differential pressure between the exhaust gas and the intake air. Thereby, when the exhaust recirculation means for recirculating the exhaust of the engine is provided, the intake air amount measuring device according to the present invention can further improve the calculation accuracy of the flow rate of the intake air flowing through the intake pipe.

In the intake air amount measuring device according to the present invention, preferably, the differential pressure detecting means is based on the pressure of the intake air located at the same position in the longitudinal direction as the intake air whose pressure is detected by the pressure detecting means. It is characterized in that the differential pressure is detected.

According to the intake air amount measuring device according to the present invention, the differential pressure detecting means includes exhaust and intake based on the pressure of the intake air whose pressure is detected by the pressure detecting means and the intake air which is located at the same position in the longitudinal direction of the intake air distribution means. Detects the differential pressure of. That is, the position where the pressure of the intake air is detected by the differential pressure detecting means is the same as the position where the pressure of the intake air is detected by the pressure detecting means, that is, the position of the region extending between the first branch portion and the second branch portion. Therefore, the pressure of the intake air in the intake air distribution means for detecting the differential pressure by the differential pressure detecting means and the pressure of the intake air in the intake air distribution means detected by the pressure detecting means are time-synchronized with each other. Therefore, the calculation unit calculates the flow rate of the intake air flowing through the intake air distribution means and the flow rate of the exhaust gas flowing through the exhaust gas return means from one system in the intake air distribution means, that is, a system in the same state. Thereby, when the exhaust recirculation means for recirculating the exhaust of the engine is provided, the intake air amount measuring device according to the present invention can further improve the calculation accuracy of the flow rate of the intake air flowing through the intake pipe.

In the intake air amount measuring device according to the present invention, preferably, the differential pressure detecting means flows through the cooling means for cooling the exhaust gas flowing through the exhaust gas return means and the exhaust gas return means downstream of the cooling means. It is characterized in that the differential pressure is detected based on the pressure of the exhaust gas between the flow rate adjusting means for adjusting the flow rate of the exhaust gas.

According to the intake air amount measuring device according to the present invention, the differential pressure detecting means is exhausted and intake air based on the pressure of the exhaust air between the cooling means and the flow rate adjusting means provided on the downstream side of the cooling means. Detects the differential pressure with. As a result, the calculation unit can estimate the degree of deterioration or the degree of deterioration of the cooling means based on the differential pressure transmitted by the differential pressure detecting means.

The intake air amount measuring device according to the present invention preferably further includes a spacer provided in the exhaust / recirculation means between the cooling means and the flow rate adjusting means, and the spacer is the exhaust flowing through the exhaust / recirculation means. The differential pressure detecting means has a hole formed so as to penetrate in a direction intersecting the flow of the spacer, and the differential pressure detecting means detects the differential pressure based on the pressure of the exhaust taken out through the hole of the spacer. It is characterized by.

According to the intake amount measuring device according to the present invention, when the exhaust recirculation means for recirculating the exhaust gas of the engine is provided, the spacer is a cooling means for cooling the exhaust gas and a flow rate adjusting means for adjusting the flow rate of the exhaust gas. It is provided in the exhaust / return means between the spaces. Then, the differential pressure detecting means detects the differential pressure based on the pressure of the exhaust gas taken out through the hole of the spacer. Therefore, a path such as a pipe that transmits the exhaust pressure to the differential pressure detecting means can be reliably connected to the spacer with almost no structural restrictions from the cooling means and the flow rate adjusting means. Further, by changing the structure of the spacer without changing the structure of the cooling means and the flow rate adjusting means, it is possible to easily connect various pipes and the like for transmitting the exhaust pressure to the differential pressure detecting means to the spacer. can. Further, the holes of the spacer are formed so as to penetrate in a direction intersecting with the flow of the exhaust gas flowing through the exhaust gas return means. Therefore, it is possible to prevent the pores of the spacer from being blocked by the particulate matter (PM: Particulate Matter) contained in the exhaust. As a result, the differential pressure detecting means can more reliably acquire the exhaust pressure (static pressure) and detect the differential pressure with higher accuracy based on the exhaust pressure (static pressure).

The intake air amount measuring device according to the present invention preferably further includes an exhaust pressure acquisition path that is connected to the spacer and the differential pressure detecting means and transmits the pressure of the exhaust taken out through the hole to the differential pressure detecting means. At least a portion of the exhaust pressure acquisition path connected to the spacer is made of metal.

According to the intake air amount measuring device according to the present invention, the exhaust pressure acquisition path is connected to the spacer and the differential pressure detecting means, and the pressure of the exhaust taken out through the hole of the spacer is transmitted to the differential pressure detecting means. At least the portion of the exhaust pressure acquisition path connected to the spacer is made of metal. Therefore, it is possible to prevent the portion of the exhaust pressure acquisition path connected to the spacer from being deteriorated or hardened by the heat of the exhaust gas flowing through the exhaust gas return means. As a result, it is possible to prevent a gap from being created between the spacer and the portion of the exhaust pressure acquisition path connected to the spacer, and the air outside the exhaust pressure acquisition path enters the inside of the exhaust pressure acquisition path. Can be suppressed. As a result, the differential pressure detecting means can detect the differential pressure with higher accuracy. Further, since the portion of the exhaust pressure acquisition path connected to the spacer is made of metal, the exhaust pressure acquisition path can be fastened to the spacer by using a screw structure. As a result, it is possible to prevent the exhaust pressure acquisition path from coming off the spacer, and to easily position the exhaust pressure acquisition path with respect to the spacer.

Further, the subject is an engine provided with an intake air amount measuring device for measuring an intake air flow rate and having three or more cylinders in series, and the intake air amount measuring device distributes the intake air to the cylinders of the engine. The intake air distribution means, the temperature detecting means for detecting the temperature of the intake air, the pressure detecting means for detecting the pressure of the intake air, the temperature transmitted from the temperature detecting means, and the pressure transmitted from the pressure detecting means. It has a calculation unit that calculates the flow rate based on the pressure, and the longitudinal direction of the intake air distribution means is along the direction in which the cylinders of the engine are lined up, and the intake air is taken from one end of the longitudinal direction. The intake air distribution means that flows into the intake air distribution means and is connected to the first cylinder of the engine provided at the position farthest from one end in the longitudinal direction inside the intake air distribution means. The first branch of the means and the second branch of the intake air distribution means connected to the second cylinder of the engine provided at a position far from the one end next to the first cylinder in the longitudinal direction. The temperature of the intake air at a position between the two is detected , and the pressure detecting means is the temperature of the intake air at the position between the first branch and the second branch by the temperature detecting means. The present invention relates to the present invention, which detects the pressure of the intake air located closer to one end in the longitudinal direction than the intake air to be detected and transmitted through the intake air pressure acquisition path. It is solved by the engine.

According to the engine provided with the intake air amount measuring device according to the present invention, the longitudinal direction of the intake air distribution means for distributing the intake air to the cylinders of the engine is along the direction in which the cylinders of the engine are lined up. The intake air of the engine flows into the intake air distribution means from one end in the longitudinal direction of the intake air distribution means. Then, the calculation unit calculates the flow rate of the intake air based on the temperature of the intake air transmitted from the temperature detecting means and the pressure of the intake air transmitted from the pressure detecting means. The temperature detecting means detects the temperature of the intake air located between the first branch portion of the intake air distribution means and the second branch portion of the intake air distribution means. The first branch portion is connected to the first cylinder of the engine provided at the position farthest from one end of the intake air distribution means in the longitudinal direction of the intake air distribution means. The second branch portion is connected to the second cylinder of the engine provided at a position far from one end of the intake air distribution means next to the first cylinder of the engine in the longitudinal direction of the intake air distribution means. As described above, the temperature detecting means detects the temperature of the intake air at a position where the intake air flow is relatively stable in the region in the intake air distribution means. Then, the calculation unit determines the temperature of the intake air transmitted from the temperature detecting means and the pressure of the intake air transmitted from the pressure detecting means, regardless of the intake amount sensor (MAF sensor) that detects the flow rate of the intake air flowing through the intake pipe. The flow rate of intake air is calculated based on. As a result, the engine provided with the intake air amount measuring device according to the present invention can suppress that the measurement result of the intake air flow flow through the intake air pipe depends on the shape of the intake air pipe, and can stably measure the intake air flow rate. can.
According to the engine provided with the intake air amount measuring device according to the present invention, the pressure detecting means, like the temperature detecting means, is the pressure of the intake air at a position where the intake air flow is relatively stable in the region in the intake air distribution means. Is detected. Then, the calculation unit calculates the flow rate of the intake air based on the temperature of the intake air transmitted from the temperature detecting means and the pressure of the intake air transmitted from the pressure detecting means, regardless of the intake amount sensor (MAF sensor). .. As a result, the engine provided with the intake air amount measuring device according to the present invention further suppresses that the measurement result of the intake air flow flow through the intake air pipe depends on the shape of the intake air pipe, and further stabilizes the intake air flow rate. Can be measured.
According to the engine provided with the intake air amount measuring device according to the present invention, the pressure detecting means is located closer to one end of the intake air distribution means in the longitudinal direction of the intake air distribution means than the intake air whose temperature is detected by the temperature detecting means. Detects intake pressure. Therefore, the pressure detecting means is not the intake air in the position where the flow is disturbed by, for example, the probe of the temperature detecting means installed in the intake air distribution means, but the intake air in the more stable position before the flow is disturbed. Detect pressure. Therefore, the pressure detecting means can detect the pressure of the intake air more stably. As a result, the engine provided with the intake air amount measuring device according to the present invention further suppresses that the measurement result of the intake air flow flow through the intake air pipe depends on the shape of the intake air pipe, and further stabilizes the intake air flow rate. Can be measured.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide an intake air amount measuring device and an engine capable of stably measuring the intake air flow rate by suppressing the measurement result of the intake air flow rate flowing through the intake air pipe from depending on the shape of the intake air pipe. Can be done.

It is a schematic diagram which shows the engine which includes the intake air amount measuring apparatus which concerns on embodiment of this invention. It is a schematic diagram which illustrates the result of the turbulent flow energy of the CFD fluid analysis carried out by the present inventor. It is a schematic diagram which illustrates the result of the pressure of the CFD fluid analysis carried out by the present inventor. It is a schematic diagram which illustrates the result of the temperature of the CFD fluid analysis carried out by the present inventor. It is a perspective view which shows the specific structural example of the spacer and the exhaust pressure acquisition path of this embodiment. It is sectional drawing which shows the structural example of the spacer of this embodiment.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
Since the embodiments described below are suitable specific examples of the present invention, various technically preferable limitations are added, but the scope of the present invention is particularly limited to the present invention in the following description. Unless otherwise stated, the present invention is not limited to these aspects. Further, in each drawing, the same components are designated by the same reference numerals, and detailed description thereof will be omitted as appropriate.

(Overview of Engine 1)
FIG. 1 is a schematic view showing an engine including an intake air amount measuring device according to an embodiment of the present invention.
First, an outline of the engine 1 including the intake air amount measuring device according to the present embodiment will be described. The engine 1 shown in FIG. 1 is an internal combustion engine, for example, an industrial diesel engine. The engine 1 is a vertical in-line multi-cylinder engine such as a supercharged high-output 4-cylinder engine with a turbocharger. The engine 1 is mounted on a vehicle such as a construction machine, an agricultural machine, or a lawn mower.

The engine 1 shown in FIG. 1 includes a cylinder head 2, an intake manifold (intake manifold) 3, an exhaust manifold (exhaust manifold) 4, a turbocharger 5, an intake throttle valve (intake adjustment unit) 6, and an EGR (Exhaust). It includes a Gas Recirculation (exhaust gas recirculation) valve 7, an EGR cooler 8, and an intake air amount measuring device 200 having an ECU (Electronic Control Unit) 100. It should be noted that the exhaust gas recirculation means for recirculating the exhaust gas of the engine 1 such as the EGR valve 7, the EGR cooler 8, and the EGR gas path 23 described later may not necessarily be provided. The "manifold" is also called the "manifold". Further, the intake manifold 3 of the present embodiment is an example of the "intake distribution means" of the present invention. The ECU 100 of the present embodiment is an example of the "calculation unit" of the present invention. The EGR valve 7 of the present embodiment is an example of the "flow rate adjusting means" of the present invention. The EGR cooler 8 of the present embodiment is an example of the "cooling means" of the present invention.

The cylinder head 2 of the engine 1 is, for example, a cylinder head of a vertical in-line multi-cylinder engine having a first cylinder 11, a second cylinder 12, a third cylinder 13, and a fourth cylinder 14. In the present specification, when viewed along the direction in which a plurality of cylinders are lined up, that is, the direction in which the crank shaft is extended, the intake AR that has passed through the intake throttle valve 6 and the exhaust gas recirculation gas ECG that has passed through the EGR valve 7 are mutually exclusive. The first cylinder, the second cylinder, the third cylinder, and the fourth cylinder will be referred to in order from the cylinder provided at a position far from the mixed portion (mixing portion) 24 toward the cylinder provided at a position closer to the mixed portion (mixing portion) 24. ..

As shown in FIG. 1, the intake manifold 3 includes a main pipe 35 having a start end portion 351 into which intake air flows in at one end, and a first branch pipe 31, a second branch pipe 32, and a third branch pipe branching from the main pipe 35. It has 33 and a fourth branch pipe 34. The starting end portion 351 of the present embodiment is an example of the "one end" of the present invention. The first branch pipe 31, the second branch pipe 32, the third branch pipe 33, and the fourth branch pipe 34 of the present embodiment are the "first branch portion", the "second branch portion", and the "third branch" of the present invention. It is an example of each of "part" and "fourth branch part". The longitudinal direction of the main pipe 35 is along the direction in which the first cylinder 11, the second cylinder 12, the third cylinder 13, and the fourth cylinder 14 are lined up, that is, the direction in which the crankshaft extends. The first branch pipe 31, the second branch pipe 32, the third branch pipe 33, and the fourth branch pipe 34 of the intake manifold 3 are the first cylinder 11, the second cylinder 12, the third cylinder 13, and the fourth cylinder 14. Are connected to each other. A fuel injection valve 15 is provided in each combustion chamber of the first cylinder 11, the second cylinder 12, the third cylinder 13, and the fourth cylinder 14. The fuel injection valve 15 is connected to the common rail 16. Fuel in a fuel tank (not shown) is sent to the common rail 16 by the operation of the fuel pump. The common rail 16 stores the fuel sent from the fuel pump under the control of the ECU 100. The fuel accumulated in the common rail 16 is injected from each fuel injection valve 15 into each combustion chamber.

(Turbocharger 5)
As shown in FIG. 1, the turbocharger 5 has a turbine 5T and a blower 5B, and supercharges the intake air sent to the intake manifold 3. That is, the portion of the blower 5B is connected to the intake pipe 20 and the intake passage 21. The intake passage 21 is connected to the inlet flange 22 of the intake manifold 3 via the intake throttle valve 6. The portion of the turbine 5T is connected to the exhaust passage 4B. When the exhaust gas EG guided through the exhaust passage 4B of the exhaust manifold 4 is supplied to the turbine 5T of the turbocharger 5, the turbine 5T and the blower 5B rotate at high speed. As the blower 5B rotates at high speed, the intake AR supplied and compressed to the blower 5B of the turbocharger 5 is supercharged to the intake manifold 3 through the intake passage 21.

The exhaust gas EG discharged from the turbine 5T is discharged to the outside of the engine 1 via a DPF (Diesel particulate filter) 19 or the like.

As shown in FIG. 1, the starting end portion 23M of the EGR gas path 23 as an exhaust gas recirculation path is connected to the exhaust manifold 4. Alternatively, the starting end 23M of the EGR gas path 23 may be connected to the exhaust passage 4B between the exhaust manifold 4 and the turbine 5T. The EGR gas path 23 of the present embodiment is an example of the "exhaust gas recirculation means" of the present invention. The end portion 23N of the EGR gas path 23 is connected to an inlet flange 22 between the intake throttle valve 6 and the start end portion 351 of the intake manifold 3. The EGR gas path 23 is provided with an EGR valve 7, an EGR cooler 8, and a spacer 400. The EGR cooler 8 cools the exhaust gas recirculation gas ECG flowing through the EGR gas path 23.

The ECU 100 controls the operation of the intake throttle valve 6, the EGR valve 7, the common rail 16, and the like. The intake throttle valve 6 controls the supply amount of the intake AR supplied to the inlet flange 22 of the intake manifold 3 by the command of the ECU 100 based on the depression amount of the accelerator pedal. The EGR valve 7 adjusts the supply amount of the exhaust gas recirculation gas ECG supplied from the exhaust manifold 4 to the inlet flange 22 of the intake manifold 3 according to the command of the ECU 100.

(Intake amount measuring device 200)
Next, the intake air amount measuring device 200 according to the present embodiment will be described.
The intake amount measuring device 200 includes a pressure sensor 201, a temperature sensor 202, an EGR differential pressure sensor 203, and an ECU 100. The pressure sensor 201 of the present embodiment is an example of the "pressure detecting means" of the present invention. The temperature sensor 202 of the present embodiment is an example of the "temperature detection means" of the present invention. The EGR differential pressure sensor 203 of the present embodiment is an example of the "differential pressure detecting means" of the present invention.

The pressure sensor 201 detects the pressure Pi of the mixed intake CYL in the first pressure measuring unit 213 installed in the intake manifold 3 and transmits it to the ECU 100. Specifically, the intake pressure acquisition path 230 such as a pipe is connected to the intake manifold 3, the pressure sensor 201, and the EGR differential pressure sensor 203. The pressure sensor 201 detects the pressure Pi of the mixed intake CYL in the first pressure measuring unit 213 taken out and transmitted through the intake pressure acquisition path 230. The mixed intake CYL is a gas in which the intake AR that has passed through the intake throttle valve 6 and the exhaust gas recirculation gas ECG that has passed through the EGR valve 7 are mixed with each other.

The temperature sensor 202 is installed in the intake manifold 3, detects the temperature Ti of the mixed intake CYL in the intake manifold 3, and transmits the temperature Ti to the ECU 100.

The EGR differential pressure sensor 203 is a differential pressure between the pressure Pi of the mixed intake CYL in the first pressure measuring unit 213 and the pressure Pe of the exhaust gas recirculation gas ECG in the second pressure measuring unit 223 installed in the EGR gas path 23. The PP is detected and transmitted to the ECU 100. Specifically, as shown in FIG. 1, the intake pressure acquisition path 230 has a portion connected to the pressure sensor 201 from the intake manifold 3 toward the pressure sensor 201 and the EGR differential pressure sensor 203, and the EGR differential pressure. It is branched into a portion connected to the sensor 203. The EGR differential pressure sensor 203 detects the differential pressure PP based on the pressure Pi of the mixed intake CYL in the first pressure measuring unit 213 taken out and transmitted through the intake pressure acquisition path 230. That is, the EGR differential pressure sensor 203 detects the differential pressure PP based on the pressure Pi of the mixed intake CYL at the same position as the mixed intake CYL whose pressure Pi is detected by the pressure sensor 201. In other words, the pressure sensor 201 and the EGR differential pressure sensor 203 detect the pressure Pi of the mixed intake CYL in the first pressure measuring unit 213 that is temporally synchronized with each other in the intake manifold 3. Further, the second pressure measuring unit 223 is installed in the EGR gas path 23 between the EGR cooler 8 and the EGR valve 7. Specifically, the exhaust pressure acquisition path 500 such as a pipe is connected to the EGR gas path 23 and the EGR differential pressure sensor 203. The EGR differential pressure sensor 203 detects the differential pressure PP based on the pressure Pe of the exhaust gas recirculation gas ECG in the second pressure measuring unit 223 taken out and transmitted through the exhaust pressure acquisition path 500. The details of the installation positions of the first pressure measuring unit 213 and the temperature sensor 202 will be described later.

As shown in FIG. 1, a spacer 400 is provided in the EGR gas path 23 between the EGR cooler 8 as the cooling means and the EGR valve 7 as the flow rate adjusting means. The spacer 400 is made of a heat-resistant metal such as stainless steel or iron. The second pressure measuring unit 223 is preferably set in the metal spacer 400. The exhaust pressure acquisition path 500 is connected to the spacer 400 and the EGR differential pressure sensor 203.

The exhaust pressure acquisition path 500 has a first portion 501 connected to the spacer 400 and a second portion 502 connected to the first portion 501 and also connected to the EGR differential pressure sensor 203. The first portion 501 connected to at least the spacer 400 of the exhaust pressure acquisition path 500 is made of a heat-resistant metal such as stainless steel or iron. The remaining second portion 502 of the exhaust pressure acquisition path 500 is made of a flexible, heat resistant engineering plastic, a resin such as rubber. Specific structural examples of the spacer 400 and the exhaust pressure acquisition path 500 will be described with reference to FIG. 5, and structural examples of the spacer 400 will be described with reference to FIG.

FIG. 5 is a perspective view showing a specific structural example of the spacer and the exhaust pressure acquisition path of the present embodiment.
FIG. 6 is a cross-sectional view showing a structural example of the spacer of the present embodiment.
Note that FIG. 6 is a cross-sectional view taken along the cutting surface AA (see FIG. 5) perpendicular to the flow direction of the exhaust gas recirculation gas ECG flowing through the EGR gas path 23.

As shown in FIG. 5, the spacer 400 is attached between the EGR cooler 8 and the EGR valve 7. The EGR cooler base 550 shown in FIG. 5 is fixed to the cylinder head 2 and supports the EGR cooler 8, the EGR valve 7, and the spacer 400. The exhaust gas recirculation gas ECG indicated by the arrow is sent to the EGR valve 7 through the EGR cooler base 550, the EGR cooler 8 and the spacer 400 in this order.

The spacer 400 is arranged in the middle of the flow direction of the exhaust gas recirculation gas ECG indicated by the arrow in the EGR gas path 23 as the exhaust gas recirculation path. More specifically, the spacer 400 is arranged between the end portion 8M of the EGR cooler 8 and the start end portion 7N of the EGR valve 7. The spacer 400 is formed so as to have a wall thickness as thin as possible (for example, a wall thickness of about 10 mm) with respect to the flow direction of the exhaust gas recirculation gas ECG indicated by the arrow in order to prevent the engine 1 from becoming large in size.

By the way, the EGR differential pressure sensor 203 uses the spacer 400 and the exhaust pressure acquisition path 500, and the differential pressure PP is based on the pressure Pe of the exhaust gas recirculation gas ECG taken out from between the EGR cooler 8 and the EGR valve 7. One of the reasons for detecting the above is to be able to detect the deterioration of the EGR cooler 8. For example, when the EGR cooler 8 is blocked by a particulate matter even a little, the pressure Pe of the exhaust gas recirculation gas ECG between the EGR cooler 8 and the EGR valve 7 provided on the downstream side of the EGR cooler 8 The differential pressure PP changes based on. Therefore, the exhaust pressure acquisition path 500 is connected to the spacer 400 provided between the end portion 8M on the downstream side of the EGR cooler 8 and the start end portion 7N on the upstream side of the EGR valve 7. .. Then, the EGR differential pressure sensor 203 detects the differential pressure PP based on the pressure Pe of the exhaust gas recirculation gas ECG in the second pressure measuring unit 223 in the spacer 400.

As shown in FIG. 6, the first portion 501 of the exhaust pressure acquisition path 500 has a male screw portion 503 at a portion connected to the spacer 400. By fastening the male threaded portion 503 to the female threaded portion 404 of the spacer 400 in a threaded structure, the first portion 501 of the exhaust pressure acquisition path 500 is connected to the spacer 400. Further, as shown in FIG. 5, the first portion 501 of the exhaust pressure acquisition path 500 is supported by the spacer 400 via the mounting bracket 520. The mounting bracket 520 is fixed to the spacer 400 by fastening the bolt 521 to the female thread portion 403 of the spacer 400, and supports the first portion 501 of the exhaust pressure acquisition path 500. The mounting bracket 520 suppresses the position of the first portion 501 of the exhaust pressure acquisition path 500 from being displaced, and also suppresses the exhaust pressure acquisition path 500 from being disengaged from the spacer 400 and the EGR differential pressure sensor 203 due to engine vibration or the like.

As shown in FIG. 6, the mounting surface 405 of the spacer 400 to which the seat surface of the male screw portion 503 contacts and the mounting surface 406 of the spacer 400 on which the mounting bracket 520 is mounted are on the same side surface of the spacer 400. It is provided (on the left side in FIG. 6). As a result, the operator or the like can approach the work of attaching the exhaust pressure acquisition path 500 to the spacer 400 and the work of attaching the mounting bracket 520 to the spacer 400 from the same side outside the engine 1. More preferably, the mounting surface 405 of the spacer 400 and the mounting surface 406 of the spacer 400 are coplanar to each other. As a result, the mounting surface 405 of the spacer 400 and the mounting surface 406 of the spacer 400 can be machined in the same process, and the structure of the spacer 400 can be simplified.

As shown in FIG. 6, the spacer 400 has a circular gas through hole 401 for passing the exhaust gas return gas ECG and two mounting holes provided at both sides of the gas through hole 401 with the gas through hole 401 interposed therebetween. It has holes 402 and 402, and a gas pressure acquisition hole 410 for taking out the pressure Pe of the exhaust gas return gas ECG in the second pressure measuring unit 223 in the spacer 400. The gas pressure acquisition hole 410 of the present embodiment is an example of the "hole" of the present invention.

The gas through hole 401 passes the exhaust gas return gas ECG in the direction perpendicular to the paper surface of FIG. Further, for example, a positioning stud (not shown) provided at the end 8M of the EGR cooler 8 shown in FIG. 5 passes through the holes 402 and 402, so that the spacer 400 is positioned toward the end 8M using the stud. There is.

The gas pressure acquisition hole 410 is formed so as to pass through the spacer 400 in a direction intersecting the flow of the exhaust gas recirculation gas ECG flowing through the EGR gas path 23, for example, in the vertical direction TD. In the structural example of the spacer 400 shown in FIG. 6, the gas pressure acquisition hole 410 is formed in the TD direction perpendicular to the flow of the exhaust gas recirculation gas ECG flowing through the EGR gas path 23, and the spacer 400 is formed via the female thread portion 404. It penetrates. In the present specification, "the gas pressure acquisition hole 410 penetrates the spacer 400" means that the gas pressure acquisition hole 410 communicates between the gas through hole 401 and the outside of the spacer 400 through another hole such as the female thread portion 404. It shall include the state of being allowed to do so. The pressure Pe of the exhaust gas recirculation gas ECG in the second pressure measuring unit 223 in the spacer 400 is taken out through the gas pressure acquisition hole 410 and transmitted to the EGR differential pressure sensor 203 through the exhaust pressure acquisition path 500. In other words, the exhaust pressure acquisition path 500 transmits the pressure Pe of the exhaust gas recirculation gas ECG taken out through the gas pressure acquisition hole 410 to the EGR differential pressure sensor 203. Then, the EGR differential pressure sensor 203 is taken out through the gas pressure acquisition hole 410 of the spacer 400 and transmitted by the exhaust pressure acquisition path 500 to the pressure Pe of the exhaust return gas ECG in the second pressure measuring unit 223 and the intake pressure acquisition path 230. The differential pressure PP of the pressure Pi of the mixed intake CYL in the first pressure measuring unit 213 taken out and transmitted through is detected.

The direction of the axis of the gas pressure acquisition hole 410 is not limited to the TD in the direction perpendicular to the flow of the exhaust gas recirculation gas ECG flowing through the EGR gas path 23. The direction of the axis of the gas pressure acquisition hole 410 may be a direction intersecting the flow of the exhaust gas recirculation gas ECG flowing through the EGR gas path 23, for example, the flow of the exhaust gas recirculation gas ECG flowing through the EGR gas path 23. It may have a component in the opposite direction.

The ECU 100 has an exhaust gas recirculation air amount mf _egr of the exhaust gas recirculation gas ECG in the EGR gas path 23 as an exhaust gas recirculation path based on the differential pressure PP detected by the EGR differential pressure sensor 203 and the opening degree of the EGR valve 7. Is calculated. Details of the calculation of the exhaust gas recirculation air amount mf _egr will be described later.

The EGR cooler base 550 is fixed to the cylinder head 2 and the starting end portion 8N of the EGR cooler 8. Even if the spacer 400 is provided between the EGR valve 7 and the EGR cooler 8, the EGR cooler base 550 is made thinner in order to suppress the increase in size of the engine 1. At this time, it is possible to suppress the change in the cross-sectional area of the internal flow path of the EGR cooler base 550 before and after the thinning of the EGR cooler base 550, and the flow rate, pressure and temperature of the exhaust gas recirculation gas ECG flowing through the EGR gas path 23 change. Is suppressed. For example, the cross-sectional area of the narrowest internal flow path among the internal flow paths of the EGR cooler base 550 is kept the same before and after the thinning of the EGR cooler base 550. As a result, before and after the thinning of the EGR cooler base 550, the pressure Pe of the exhaust gas recirculation gas ECG in the second pressure measuring unit 223 is suppressed from changing, and the differential pressure PP detected by the EGR differential pressure sensor 203 changes. It can be suppressed. Further, it is possible to suppress the change in the basic performance of the EGR (Exhaust Gas Recirculation) before and after the thinning of the EGR cooler base 550.

<Calculation example of the intake amount mf _air in the intake pipe 20 using the intake amount measuring device 200>
Next, a calculation example of the flow rate (intake amount mf _air ) of the intake AR in the intake pipe 20 using the intake amount measuring device 200 will be described.
Generally, in an internal combustion engine such as a diesel engine, an intake amount sensor (MAF sensor) for detecting the intake amount of air (intake) flowing through the intake pipe is provided in the intake pipe. The intake amount is the flow rate of air (intake) flowing through the intake pipe, and is also called an intake flow rate or MAF. However, the output characteristic of the intake air amount sensor provided in the intake pipe depends on the shape of the intake system (for example, the intake pipe) on the upstream side of the intake air amount sensor. The intake system on the upstream side of the intake amount sensor differs depending on the application installed in, for example, an industrial diesel engine. Therefore, the calibration work of the intake air amount sensor is required for each application mounted on the engine, which is complicated.

Therefore, in the intake air amount measuring device 200 according to the present embodiment, the ECU 100 suppresses that the measurement result of the intake air amount mf _air in the intake air pipe 20 depends on the shape of the intake air pipe 20, as described below, and takes in air. The intake amount mf _air in the pipe 20 is stably measured.

That is, in the intake amount calculation method in the present embodiment, the ECU 100 first first detects the pressure Pi of the mixed intake intake CYL in the intake manifold 3 detected by the pressure sensor 201 and the mixed intake intake CYL in the intake manifold 3 detected by the temperature sensor 202. Based on the temperature Ti of the above, the flow rate (intake amount mf _cyl ) of the mixed intake CYL supplied into the cylinders from the first cylinder 11 to the fourth cylinder 14 shown in FIG. 1 is calculated. Specifically, the ECU 100 calculates the intake amount mf _cyl of the mixed intake CYL based on the pressure Pi of the mixed intake CYL and the temperature Ti of the mixed intake CYL using the gas state equation. In an engine that does not have an exhaust gas recirculation means such as the EGR gas path 23, the intake amount mf _coil described above becomes the intake amount mf _air of the intake AR described later.

Next, the ECU 100 determines the intake amount mf _air of the intake AR flowing through the intake pipe 20 shown in FIG. 1 based on the intake amount mf _cil of the mixed intake CYL and the exhaust return air amount mf _egr of the exhaust return gas ECG. calculate. Specifically, the ECU 100 calculates the difference between the calculated intake amount mf _cil and the exhaust gas recirculation air amount mf _egr of the exhaust gas recirculation gas ECG flowing through the EGR gas path 23, and is shown in FIG. The intake amount mf _air of the intake AR flowing through the intake pipe 20 is calculated.

The exhaust gas recirculation air amount mf _egr is a function of the opening degree of the EGR valve 7 and the differential pressure PP (the differential pressure between the pressure Pi of the mixed intake CYL and the pressure Pe of the exhaust gas recirculation gas ECG). It is stored in advance in the ROM or the like of the ECU 100 in the form of (map). When the ECU 100 performs the calculation, the exhaust gas recirculation air amount table (exhaust gas recirculation air amount table) stored in advance in the ROM or the like of the ECU 100 according to the opening degree of the EGR valve 7 and the differential pressure PP detected by the EGR differential pressure sensor 203 ( Map) is read.

As described above, the ECU 100 includes the pressure Pi of the mixed intake CYL in the intake manifold 3 detected by the pressure sensor 201 shown in FIG. 1, the temperature Ti of the mixed intake CYL in the intake manifold 3 detected by the temperature sensor 202, and the EGR. Based on the differential pressure PP (differential pressure between the pressure Pi of the mixed intake CYL and the pressure Pe of the exhaust recirculation gas ECG) detected by the differential pressure sensor 203, the new intake AR in the intake pipe 20 shown in FIG. 1 The intake amount mf _air can be calculated.

As a result, in the intake air amount measuring device 200 and the engine 1 according to the present embodiment, the ECU 100 suppresses that the measurement result of the intake air amount mf _air depends on the shape of the intake air pipe 20, and stably measures the intake air amount mf _air . can do.

<Set position of the first pressure measuring unit 213 and the temperature sensor 202>
Next, the set position PS of the first pressure measuring unit 213 and the temperature sensor 202 will be described with reference to FIGS. 1 to 4.
FIG. 2 is a schematic diagram illustrating the results of turbulent energy in the CFD fluid analysis carried out by the present inventor.
FIG. 3 is a schematic diagram illustrating the results of pressure in the CFD fluid analysis performed by the present inventor.
FIG. 4 is a schematic diagram illustrating the temperature results of the CFD fluid analysis carried out by the present inventor.
2 (A), 3 (A), and 4 (A) are model diagrams illustrating the analysis results of the first cylinder 11 during the intake process. 2 (B), 3 (B), and 4 (B) are model diagrams illustrating the analysis results of the second cylinder 12 during the intake process. 2 (C), 3 (C), and 4 (C) are mock diagrams illustrating the analysis results of the third cylinder 13 during the intake process. 2 (D), 3 (D), and 4 (D) are model diagrams illustrating the analysis results of the fourth cylinder 14 during the intake process.

In order to further suppress that the measurement result of the intake air amount mf _air depends on the shape of the intake pipe 20 and to measure the intake air amount mf _air more stably, the first pressure measuring unit 213 and the temperature sensor 202 are used for intake air. It is desirable that the mixed intake CYL be installed at a position where the pulsation of the mixed intake CYL is relatively small in the manifold 3, that is, a position where the flow of the mixed intake CYL is relatively stable in the intake manifold 3. The pulsation of the mixed intake CYL in the intake manifold 3 is affected by the opening / closing operation of the intake valve (not shown) and the exhaust valve (not shown) of the engine 1 and the mixing of the intake AR and the exhaust return gas ECG.

Therefore, the present inventor performed a CFD (Computational Fluid Dynamics) fluid analysis as illustrated below in order to confirm the turbulent flow energy, pressure, and temperature of the mixed intake CYL in the intake manifold 3. ..

That is, to explain the outline of the analysis conditions (physical model), the target fluid is a three-dimensional gas (air) and an incompressible fluid (constant density). The flow of the target fluid is a steady flow as well as a turbulent flow. The turbulence model is a Realizable k-ε model. The velocity distribution of the target fluid in the vicinity of the wall surface is based on the wall function (two-layer All y + model). The solver is a separate solver. No heat transfer calculation is performed. The reference calculation grid size is 5 mm.

Further, as an analysis condition, the engine is a turbo diesel engine. The rated rotation of the engine is 2600 rpm. The engine is fully loaded. The engine is an EGR specification engine having an EGR gas path 23, an EGR valve 7, and an EGR cooler 8.

As shown in FIGS. 2A to 4D, the intake manifold 3 to be analyzed has a main pipe 35 having a start end portion 351 into which intake air flows in at one end and a first branch branching from the main pipe 35. It has a pipe 31, a second branch pipe 32, a third branch pipe 33, and a fourth branch pipe 34. The longitudinal direction of the main pipe 35 is along the direction in which the first cylinder 11, the second cylinder 12, the third cylinder 13, and the fourth cylinder 14 are lined up, that is, the direction in which the crankshaft extends. The first branch pipe 31, the second branch pipe 32, the third branch pipe 33, and the fourth branch pipe 34 are connected to the first cylinder 11, the second cylinder 12, the third cylinder 13, and the fourth cylinder 14 of the engine 1, respectively. Will be done.

In the examples shown in FIGS. 2A to 4D, the intake manifold 3 includes the first branch pipe 31, the second branch pipe 32, the third branch pipe 33, and the fourth branch pipe 34, respectively. I have books one by one. That is, the first branch pipe 31, the second branch pipe 32, the third branch pipe 33, and the fourth branch pipe 34, which are two each, are the first cylinder 11, the second cylinder 12, the third cylinder 13, and the third cylinder 13 of the engine 1. It is connected to each of the fourth cylinders 14. However, the number of branch pipes of the intake manifold 3 connected to one cylinder of the engine 1 is not limited to this. For example, one first branch pipe 31, a second branch pipe 32, a third branch pipe 33, and a fourth branch pipe 34 are the first cylinder 11, the second cylinder 12, the third cylinder 13 and the engine 1. It may be connected to each of the fourth cylinders 14.

An inlet flange 22 that allows intake air to flow into the intake manifold 3 is connected to the start end portion 351 of the intake manifold 3. The inlet flange 22 has an EGR gas path 23 through which the exhaust gas of the engine 1 is recirculated. The exhaust gas recirculated through the EGR gas path 23 flows into the start end portion 351 of the intake manifold 3 after being mixed with the intake air at the mixing portion 24 in the inlet flange 22.

The outline of the analysis conditions (physical model) described above and the example of the result of the turbulent flow energy of the target fluid by the CFD fluid analysis performed based on the analysis conditions are as shown in FIG. An example of the pressure result of the target fluid by CFD fluid analysis is as shown in FIG. An example of the temperature result of the target fluid by CFD fluid analysis is as shown in FIG.

As shown in FIGS. 2 (A) to 2 (D), in the intake manifold 3 during the intake process of the first cylinder 11, the second cylinder 12, the third cylinder 13 and the fourth cylinder 14. The turbulent flow energy of the target fluid in the vicinity of the third cylinder 13 and the fourth cylinder 14 is higher than the turbulent flow energy of the target fluid in the vicinity of the first cylinder 11 and the second cylinder 12. The turbulent energy represents the magnitude of the turbulence of the flow of the target fluid. Therefore, in the example of the analysis results shown in FIGS. 2A to 2D, the flow fields in the vicinity of the third cylinder 13 and the fourth cylinder 14 in the intake manifold 3 are the first cylinder 11 and the first cylinder 11. It is suggested that it is more likely to be unstable than the flow field near the 2-cylinder 12. In other words, in the example of the analysis results shown in FIGS. 2A to 2D, the flow of the target fluid in the vicinity of the first cylinder 11 and the second cylinder 12 in the intake manifold 3 is the third cylinder. It is suggested that it is more stable than the flow of the target fluid near the 13th and the 4th cylinder 14.

Specifically, as shown in FIG. 2A, during the intake process of the first cylinder 11, the region 300 of the first branch pipe 31 and the region 301 from the third branch pipe 33 to the fourth branch pipe 34. , The turbulent energy of the target fluid in the regions 302, 303 and 304 is higher than the turbulent energy of the target fluid in the other regions. Further, as shown in FIG. 2B, during the intake process of the second cylinder 12, the region 305 of the second branch pipe 32, the region 306 from the third branch pipe 33 to the fourth branch pipe 34, the region 307, and the region 307 The turbulent energy of the target fluid in the region 308 is higher than the turbulent energy of the target fluid in the other regions. Further, as shown in FIG. 2C, during the intake process of the third cylinder 13, the turbulent energy of the target fluid in the region 309 and the region 310 from the third branch pipe 33 to the fourth branch pipe 34 is in another region. Higher than the turbulent energy of the target fluid in. Further, as shown in FIG. 2D, during the intake process of the fourth cylinder 14, the turbulent energy of the target fluid in the region 311 of the fourth branch pipe 34 is higher than the turbulent energy of the target fluid in the other regions.

Referring to FIGS. 2 (A) to 2 (D), in the intake manifold 3, the first branch pipe 31 connected to the first cylinder 11 extends to the second branch pipe 32 connected to the second cylinder 12. The turbulent flow energy of the target fluid in the region W, particularly the position PS between the first branch pipe 31 connected to the first cylinder 11 and the second branch pipe 32 connected to the second cylinder 12, is relatively. Low. Therefore, it can be seen that the flow of the target fluid in the region W in the intake manifold 3, particularly the position PS, is relatively stable.

Further, as shown in FIGS. 3A to 3D, the intake manifold 3 is used during the intake process of the first cylinder 11, the second cylinder 12, the third cylinder 13, and the fourth cylinder 14. Within, the pressure of the target fluid near the first cylinder 11 and the second cylinder 12 is more stable than the pressure of the target fluid near the third cylinder 13 and the fourth cylinder 14.

Specifically, as shown in FIG. 3A, during the first cylinder intake step, the pressure of the target fluid in the region W is higher than the pressure of the target fluid in the region 321 of the first branch pipe 31, and the pressure is higher than that of the target fluid. It is lower than the pressure of the target fluid in the region 322 and the region 323 from the 3 branch pipe 33 to the 4th branch pipe 34. Further, as shown in FIG. 3B, during the second cylinder intake step, the pressure of the target fluid in the region W is higher than the pressure of the target fluid in the region 324 of the second branch pipe 32, and the third branch pipe 33 It is lower than the pressure of the target fluid in the region 325 and the region 326 from to the fourth branch pipe 34. Further, as shown in FIG. 3C, during the third cylinder intake step, the pressure of the target fluid in the region W is higher than the pressure of the target fluid in the region 327 of the third branch pipe 33, and the third branch pipe 33 It is lower than the pressure of the target fluid in the region 328 and the region 329 from to the fourth branch pipe 34. Further, as shown in FIG. 3D, during the fourth cylinder intake step, the pressure of the target fluid in the region W is lower than the pressure of the target fluid in the regions 331 and 332 of the third branch pipe 33, and the fourth It is higher than the pressure of the target fluid in the region 333 and the region 334 of the branch pipe 34.

Referring to FIGS. 3A to 3D, the intake manifold 3 extends from the first branch pipe 31 connected to the first cylinder 11 to the second branch pipe 32 connected to the second cylinder 12. The fluctuation of the pressure of the target fluid in the region W, particularly the position PS between the first branch pipe 31 connected to the first cylinder 11 and the second branch pipe 32 connected to the second cylinder 12, is relatively. Few. That is, the pressure of the target fluid in the region W in the intake manifold 3, particularly the position PS, is relatively stable.

Further, as shown in FIGS. 4A to 4D, the intake manifold 3 is used during the intake process of the first cylinder 11, the second cylinder 12, the third cylinder 13, and the fourth cylinder 14. Within, the temperature of the target fluid near the first cylinder 11 and the second cylinder 12 is more stable than the temperature of the target fluid near the third cylinder 13 and the fourth cylinder 14.

Specifically, as shown in FIG. 4A, during the first cylinder intake step, the temperature of the target fluid in the region W is the region 341 and the region 342 from the third branch pipe 33 to the fourth branch pipe 34. It is lower than the temperature of the target fluid in. Further, as shown in FIG. 4B, during the second cylinder intake step, the temperature of the target fluid in the region W is the temperature of the target fluid in the regions 343 and the region 344 from the third branch pipe 33 to the fourth branch pipe 34. It is lower than the temperature. Further, as shown in FIG. 4C, during the third cylinder intake step, the temperature of the target fluid in the region W is higher than the temperature of the target fluid in the region 345 of the first branch pipe 31, and the third branch pipe 33. It is lower than the temperature of the target fluid in the region 346 from the fourth branch pipe 34 to the fourth branch pipe 34. Further, as shown in FIG. 4D, during the fourth cylinder intake step, the temperature of the target fluid in the region W is lower than the temperature of the target fluid in the regions 347, 348, and 349 of the fourth branch pipe 34. ..

Referring to FIGS. 4A to 4D, the intake manifold 3 extends from the first branch pipe 31 connected to the first cylinder 11 to the second branch pipe 32 connected to the second cylinder 12. The fluctuation in the temperature of the target fluid in the region W, particularly the position PS between the first branch pipe 31 connected to the first cylinder 11 and the second branch pipe 32 connected to the second cylinder 12, is relatively Few. That is, the temperature of the target fluid in the region W in the intake manifold 3, particularly the position PS, is relatively stable.

According to the result of the CFD fluid analysis carried out by the present invention, in the direction in which the first cylinder 11, the second cylinder 12, the third cylinder 13 and the fourth cylinder 14 are arranged side by side, that is, in the longitudinal direction of the main pipe 35 of the intake manifold 3. When viewed along, the turbulent flow energy of the target fluid is relatively low, and the pressure and temperature of the target fluid are relatively stable in the region in the intake manifold 3 far from the start end portion 351. Therefore, the first pressure measuring unit 213 and the temperature sensor 202 are arranged along the direction in which the first cylinder 11, the second cylinder 12, the third cylinder 13 and the fourth cylinder 14 are arranged, that is, along the longitudinal direction of the main pipe 35 of the intake manifold 3. When viewed, it is preferable that the intake manifold 3 is installed in a region far from the start end portion 351 in the region. More specifically, the first pressure measuring unit 213 and the temperature sensor 202 have a region W extending over the first branch pipe 31 connected to the first cylinder 11 and the second branch pipe 32 connected to the second cylinder 12. In particular, it is preferably installed at the position PS between the first branch pipe 31 connected to the first cylinder 11 and the second branch pipe 32 connected to the second cylinder 12.

According to the intake air amount measuring device 200 according to the present embodiment, the temperature sensor 202 has a first branch pipe 31 connected to the first cylinder 11 and a second branch pipe 32 connected to the second cylinder 12. The temperature Ti of the mixed intake CYL in the extending region W is detected. As described above, the first branch pipe 31 is connected to the first cylinder 11 provided at the position farthest from the start end portion 351 of the intake manifold 3 in the longitudinal direction of the intake manifold 3. The second branch pipe 32 is connected to the second cylinder 12 provided at a position far from the start end portion 351 of the intake manifold 3 next to the first cylinder 11 in the longitudinal direction of the intake manifold 3. Then, the ECU 100 determines the intake amount mf _cil and the intake AR of the mixed intake CYL based on the temperature Ti of the mixed intake CYL transmitted from the temperature sensor 202 and the pressure Pi of the mixed intake CYL transmitted from the pressure sensor 201. Calculate the intake amount mf _air . That is, in an engine provided with an exhaust gas recirculation means such as the EGR gas path 23, the ECU 100 calculates the difference between the intake amount mf _coil of the mixed intake CYL and the exhaust return air amount mf _egr of the exhaust gas recirculation gas ECG. The intake amount mf _air of the intake AR is calculated by. On the other hand, in an engine that does not have an exhaust gas recirculation means such as the EGR gas path 23, the ECU 100 assumes that the intake amount mf _cil of the mixed intake CYL corresponds to the intake amount mf _air of the intake AR, and the intake amount mf of the intake AR. Calculate _air .

As described above, the temperature sensor 202 detects the temperature Ti of the mixed intake CYL in the region in the intake manifold 3 in which the flow of the mixed intake CYL is relatively stable. Then, the ECU 100 is transmitted from the temperature Ti of the mixed intake CYL transmitted from the temperature sensor 202 and from the pressure sensor 201, regardless of the intake amount sensor (MAF sensor) that detects the flow rate of the intake AR flowing through the intake pipe 20. Based on the pressure Pi of the mixed intake CYL, the intake amount mf _cil of the mixed intake CYL and the intake amount mf _air of the intake AR are calculated. As a result, the intake air amount measuring device 200 according to the present embodiment suppresses that the measurement result of the intake air amount mf _air of the intake air flowing through the intake pipe 20 does not depend on the shape of the intake air pipe 20, and the intake air amount mf _air of the intake air AR. Can be measured stably.

Further, the pressure sensor 201 detects the pressure Pi of the mixed intake CYL in the region in the intake manifold 3 in which the flow of the mixed intake CYL is relatively stable. Then, as described above, the ECU 100 has the temperature Ti of the mixed intake CYL transmitted from the temperature sensor 202 and the pressure sensor, regardless of the intake amount sensor (MAF sensor) that detects the flow rate of the intake AR flowing through the intake pipe 20. Based on the pressure Pi of the mixed intake CYL transmitted from 201, the intake amount mf _cil of the mixed intake CYL and the intake amount mf _air of the intake AR are calculated. As a result, the intake air amount measuring device 200 according to the present embodiment further suppresses that the measurement result of the intake air amount mf _air of the intake air flowing through the intake air pipe 20 depends on the shape of the intake air pipe 20, and further suppresses the intake amount of the intake air AR. The mf _air can be measured more stably.

Further, as shown in FIG. 1, the first pressure measuring unit 213 is provided at a position closer to the starting end portion 351 of the intake manifold 3 than the temperature sensor 202 in the longitudinal direction of the intake manifold 3. Therefore, the pressure sensor 201 detects the pressure Pi of the mixed intake CYL located closer to the start end portion 351 in the longitudinal direction of the intake manifold 3 than the mixed intake CYL whose temperature Ti is detected by the temperature sensor 202. Therefore, the pressure sensor 201 is not in the mixed intake CYL in the region where the flow is disturbed by, for example, the probe of the temperature sensor 202 installed in the intake manifold 3, but in the more stable region before the flow is disturbed. The pressure Pi of the mixed intake CYL is detected. Therefore, the pressure sensor 201 can more stably detect the pressure Pi of the mixed intake CYL. As a result, the intake air amount measuring device 200 according to the present embodiment further suppresses that the measurement result of the intake air amount mf _air of the intake air flowing through the intake air pipe 20 depends on the shape of the intake air pipe 20, and further suppresses the intake amount of the intake air AR. The mf _air can be measured more stably.

Further, since the first pressure measuring unit 213 is provided in the region W extending over the first branch pipe 31 and the second branch pipe 32, the EGR differential pressure sensor 203 is the mixed intake CYL in the region in the intake manifold 3. Detects the differential pressure PP between the pressure Pi of the mixed intake CYL in the region where the flow of the gas is relatively stable and the pressure Pe of the exhaust gas recirculation gas ECG in the second pressure measuring unit 223 provided in the EGR gas path 23. .. Then, the ECU 100 includes the temperature Ti of the mixed intake CYL transmitted from the temperature sensor 202, the pressure Pi of the mixed intake CYL transmitted from the pressure sensor 201, and the differential pressure PP transmitted from the EGR differential pressure sensor 203. The intake amount mf _cil of the mixed intake CYL and the intake amount mf _air of the intake AR are calculated based on the above. As a result, when the exhaust recirculation means for recirculating the exhaust of the engine 1 is provided, the intake amount measuring device 200 according to the present embodiment can improve the calculation accuracy of the intake amount mf _air of the intake AR flowing through the intake pipe 20. can.

Further, since the first pressure measuring unit 213 is provided at a position closer to the starting end portion 351 of the intake manifold 3 than the temperature sensor 202 in the longitudinal direction of the intake manifold 3, the EGR differential pressure sensor 203 is heated by the temperature sensor 202. The differential pressure PP is detected based on the pressure Pi of the mixed intake CYL located closer to the start end portion 351 in the longitudinal direction of the intake manifold 3 than the mixed intake CYL in which Ti is detected. Therefore, the EGR differential pressure sensor 203 is not a mixed intake CYL in a region where the flow is disturbed by, for example, a probe of the temperature sensor 202 installed in the intake manifold 3, but a more stable region before the flow is disturbed. The differential pressure PP is detected based on the pressure Pi of the mixed intake CYL in. Therefore, the EGR differential pressure sensor 203 can detect the differential pressure PP more stably. As a result, when the exhaust recirculation means for recirculating the exhaust of the engine 1 is provided, the intake amount measuring device 200 according to the present embodiment can improve the calculation accuracy of the intake amount mf _air of the intake AR flowing through the intake pipe 20. can.

Further, the EGR differential pressure sensor 203 is applied to the pressure Pi of the mixed intake CYL whose pressure Pi is detected by the pressure sensor 201 and the mixed intake CYL at the same position in the longitudinal direction of the intake manifold 3 (that is, the first pressure measuring unit 213). The differential pressure PP is detected based on this. That is, the detection position of the pressure Pi of the mixed intake CYL by the EGR differential pressure sensor 203 is the same as the detection position of the pressure Pi of the mixed intake CYL by the pressure sensor 201, that is, extends over the first branch pipe 31 and the second branch pipe 32. The position of the region W. Therefore, the pressure Pi of the mixed intake CYL in the intake manifold 3 for detecting the differential pressure PP by the EGR differential pressure sensor 203 and the pressure Pi of the mixed intake CYL in the intake manifold 3 detected by the pressure sensor 201 are mutually timed. Synchronize. Therefore, the ECU 100 calculates the intake amount mf _cil of the mixed intake CYL and the exhaust return air amount mf _egr of the exhaust gas recirculation gas ECG from one system in the intake manifold 3, that is, a system in the same state. As a result, when the exhaust recirculation means for recirculating the exhaust of the engine 1 is provided, the intake amount measuring device 200 according to the present embodiment can improve the calculation accuracy of the intake amount mf _air of the intake AR flowing through the intake pipe 20. can.

Further, the second pressure measuring unit 223 is provided in the EGR gas path 23 between the EGR cooler 8 and the EGR valve 7. Therefore, the EGR differential pressure sensor 203 detects the differential pressure PP based on the pressure Pe of the exhaust gas recirculation gas ECG between the EGR cooler 8 and the EGR valve 7. As a result, the ECU 100 can estimate the degree of deterioration or the degree of deterioration of the EGR cooler 8 based on the differential pressure PP transmitted by the EGR differential pressure sensor 203.

Further, the spacer 400 is provided in the EGR gas path 23 between the EGR cooler 8 and the EGR valve 7. Then, the EGR differential pressure sensor 203 detects the differential pressure PP based on the pressure Pe of the exhaust gas recirculation gas ECG taken out through the gas pressure acquisition hole 410 of the spacer 400. Therefore, the exhaust pressure acquisition path 500 that transmits the pressure Pe of the exhaust gas recirculation gas ECG to the EGR differential pressure sensor 203 can be reliably connected to the spacer 400 with almost no structural restrictions from the EGR valve 7 and the EGR cooler 8. It is said that. Further, by changing the structure of the spacer 400 without changing the structures of the EGR cooler 8 and the EGR valve 7, the exhaust pressures of various pipes and the like that transmit the pressure Pe of the exhaust gas recirculation gas ECG to the EGR differential pressure sensor 203. The acquisition path 500 can be easily connected to the spacer 400. Further, the gas pressure acquisition hole 410 of the spacer 400 is formed so as to penetrate in a direction intersecting the flow of the exhaust gas recirculation gas ECG flowing through the EGR gas path 23. Therefore, it is possible to prevent the gas pressure acquisition hole 410 of the spacer 400 from being blocked by the particulate matter (PM: Particulate Matter) contained in the exhaust gas reflux gas ECG. As a result, the EGR differential pressure sensor 203 more reliably acquires the pressure (static pressure) Pe of the exhaust gas recirculation gas ECG, and obtains the differential pressure PP with higher accuracy based on the pressure (static pressure) Pe of the exhaust gas recirculation gas ECG. Can be detected.

Further, the exhaust pressure acquisition path 500 is connected to the spacer 400 and the EGR differential pressure sensor 203, and transmits the pressure Pe of the exhaust gas recirculation gas ECG taken out through the gas pressure acquisition hole 410 of the spacer 400 to the EGR differential pressure sensor 203. The first portion 501 connected to at least the spacer 400 in the exhaust pressure acquisition path 500 is made of metal. Therefore, it is possible to prevent the first portion 501 connected to the spacer 400 of the exhaust pressure acquisition path 500 from being deteriorated or hardened by the heat of the exhaust gas recirculation gas ECG flowing through the EGR gas path 23. As a result, it is possible to prevent a gap from being created between the first portion 501 connected to the spacer 400 in the exhaust pressure acquisition path 500 and the spacer 400, and the air outside the exhaust pressure acquisition path 500 acquires the exhaust pressure. It is possible to prevent the vehicle from entering the inside of the route 500. As a result, the EGR differential pressure sensor 203 can detect the differential pressure PP with higher accuracy. Further, since the first portion 501 connected to the spacer 400 in the exhaust pressure acquisition path 500 is made of metal, the exhaust pressure acquisition path 500 can be fastened to the spacer 400 by using a screw structure. As a result, it is possible to prevent the exhaust pressure acquisition path 500 from coming off from the spacer 400, and to easily position the exhaust pressure acquisition path 500 with respect to the spacer 400.

Further, the second portion 502 connected to the EGR differential pressure sensor 203 in the exhaust pressure acquisition path 500 is made of a flexible, heat-resistant engineering plastic, a resin such as rubber, or the like. Therefore, even if the first portion 501 of the exhaust pressure acquisition path 500 is made of metal, the second portion 502 of the exhaust pressure acquisition path 500 flexibly corresponds to the position of the EGR differential pressure sensor 203 and is an EGR differential pressure sensor. It is said that it can be easily connected to 203.

The embodiment of the present invention has been described above. However, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of claims. The configuration of the above embodiment may be partially omitted or may be arbitrarily combined so as to be different from the above.
For example, as an example of the engine of the present invention, the engine 1 according to the present embodiment is illustrated. The engine 1 is a supercharged diesel engine with a turbocharger. However, the present invention is not limited to this, and the engine of the present invention may be a naturally aspirated diesel engine, a supercharged gasoline engine with a turbocharger, a naturally aspirated gasoline engine, or the like. The type of engine 1 is a multi-cylinder engine such as a supercharged high-output 4-cylinder engine equipped with a turbocharger. However, the type of the engine 1 is not limited to this, and may be an engine having three cylinders or five or more cylinders. The engine 1 can be mounted on a type of vehicle other than a vehicle such as a construction machine, an agricultural machine, or a lawn mower.

1: Engine, 2: Cylinder head, 3: Intake manifold, 4: Exhaust manifold, 4B: Exhaust passage, 5: Turbo charger, 5B: Blower, 5T: Turbine, 6: Intake throttle valve, 7: EGR valve, 8: EGR cooler, 11: 1st cylinder, 12: 2nd cylinder, 13: 3rd cylinder, 14: 4th cylinder, 15: fuel injection valve, 16: common rail, 19: diesel fine particle collection filter, 20: intake pipe , 21: Intake passage, 22: Inlet flange, 23: EGR gas path, 23M: Start end, 23N: End, 24: Mixing part, 31: 1st branch pipe, 32: 2nd branch pipe, 33: 3rd Branch pipe, 34: 4th branch pipe, 35: Main pipe, 100: ECU, 200: Intake amount measuring device, 201: Pressure sensor, 202: Temperature sensor, 203: EGR differential pressure sensor, 213: 1st pressure measuring unit , 223: 2nd pressure measuring part, 230: Intake pressure acquisition path, 351: Starting end part, 400: Spacer, 401: Gas through hole, 402: Hole, 403: Female thread part, 404: Female thread part, 405: Mounting surface, 406: Mounting surface, 410: Gas pressure acquisition hole, 500: Exhaust pressure acquisition path, 501: 1st part, 502: 2nd part, 503: Male screw part, 520: Mounting bracket, 521: Bolt, 550: EGR cooler Base, AR: Intake, CYL: Mixed intake, ECG: Exhaust gas recirculation gas, EG: Exhaust gas, PP: Differential pressure, PS: Set position, Pe, Pi: Pressure, Ti: Temperature, W: Region, mf _air , mf _cil : Intake amount, mf _egr : Exhaust gas recirculation air amount

Claims (7)

An intake amount measuring device that measures the intake flow rate of an engine having three or more cylinders in series.
An intake air distribution means for distributing the intake air to the cylinder of the engine,
A temperature detecting means for detecting the temperature of the intake air and
The pressure detecting means for detecting the pressure of the intake air and the pressure detecting means.
A calculation unit that calculates the flow rate based on the temperature transmitted from the temperature detecting means and the pressure transmitted from the pressure detecting means.
Equipped with
The longitudinal direction of the intake air distribution means is along the direction in which the cylinders of the engine are lined up.
The intake air flows into the intake air distribution means from one end in the longitudinal direction, and the intake air flows into the intake air distribution means.
The temperature detecting means includes a first branch portion of the intake air distribution means connected to the first cylinder of the engine provided at a position farthest from one end in the longitudinal direction inside the intake air distribution means. Of the intake air located between the first cylinder and the second branch of the intake air distribution means connected to the second cylinder of the engine provided at a position far from one end in the longitudinal direction. The temperature is detected and
The pressure detecting means is one end of the intake air located between the first branch portion and the second branch portion in the longitudinal direction of the intake air whose temperature is detected by the temperature detecting means. A device for measuring an intake air amount , which is the pressure of the intake air located close to the air intake pressure, and detects the pressure taken out and transmitted through the intake air pressure acquisition path . Exhaust recirculation means for recirculating the exhaust gas of the engine and
A differential pressure detecting means that detects the differential pressure between the exhaust gas flowing through the exhaust gas return means and the intake air flowing through the intake air distribution means and transmits the differential pressure to the calculation unit.
Further prepare
The calculation unit further calculates the flow rate based on the differential pressure transmitted from the differential pressure detecting means, and calculates the flow rate.
The differential pressure detecting means is said to be in the longitudinal direction from the intake air whose temperature is detected by the temperature detecting means among the intake airs located at the position between the first branch portion and the second branch portion. The intake air amount measurement according to claim 1 , wherein the differential pressure is detected based on the pressure of the intake air at the position near one end, which is taken out through the intake pressure acquisition path and transmitted. Device. The claim is characterized in that the differential pressure detecting means detects the differential pressure based on the pressure of the intake air located at the same position in the longitudinal direction as the intake air whose pressure is detected by the pressure detecting means. 2. The intake air amount measuring device according to 2. The differential pressure detecting means is between a cooling means for cooling the exhaust gas flowing through the exhaust gas return means and a flow rate adjusting means for adjusting the flow rate of the exhaust gas flowing through the exhaust gas return means downstream of the cooling means. The intake air flow rate measuring device according to claim 2 or 3 , wherein the differential pressure is detected based on the pressure of the exhaust gas. Further, a spacer provided in the exhaust / return means between the cooling means and the flow rate adjusting means is provided.
The spacer has a hole formed so as to penetrate in a direction intersecting the flow of the exhaust gas flowing through the exhaust gas recirculation means.
The intake air amount measuring device according to claim 4 , wherein the differential pressure detecting means detects the differential pressure based on the pressure of the exhaust gas taken out through the hole of the spacer. Further provided with an exhaust pressure acquisition path which is connected to the spacer and the differential pressure detecting means and transmits the pressure of the exhaust gas taken out through the hole to the differential pressure detecting means.
The intake air amount measuring device according to claim 5 , wherein at least a portion of the exhaust pressure acquisition path connected to the spacer is made of metal. An engine equipped with an intake air amount measuring device for measuring the intake air flow rate and having three or more cylinders in series.
The intake air amount measuring device is
An intake air distribution means for distributing the intake air to the cylinder of the engine,
A temperature detecting means for detecting the temperature of the intake air and
The pressure detecting means for detecting the pressure of the intake air and the pressure detecting means.
A calculation unit that calculates the flow rate based on the temperature transmitted from the temperature detecting means and the pressure transmitted from the pressure detecting means.
Have,
The longitudinal direction of the intake air distribution means is along the direction in which the cylinders of the engine are lined up.
The intake air flows into the intake air distribution means from one end in the longitudinal direction, and the intake air flows into the intake air distribution means.
The temperature detecting means includes a first branch portion of the intake air distribution means connected to the first cylinder of the engine provided at a position farthest from one end in the longitudinal direction inside the intake air distribution means. The intake air located between the first cylinder and the second branch of the intake air distribution means connected to the second cylinder of the engine provided at a position far from one end in the longitudinal direction. The temperature of the
The pressure detecting means is one end of the intake air located between the first branch portion and the second branch portion in the longitudinal direction of the intake air whose temperature is detected by the temperature detecting means. An engine characterized in that the pressure of the intake air located close to is detected by the pressure taken out and transmitted through the intake air pressure acquisition path .

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