Detachment detection device for blow-by hose

Abstract

This detachment detection device for a blow-by hose comprises: a blow-by hose that recirculates, from a crankcase to an intake tube, blow-by gas leaked from a combustion chamber of an internal combustion engine to the crankcase; a flow rate sensor that is provided to the intake tube further to the upstream side thereof in an intake direction than a connection position where the blow-by hose is connected to the intake tube, and measures a fresh air amount suctioned into the intake tube; a pressure sensor that is provided to the intake tube further to the downstream side thereof in the intake direction than said connection position of the intake tube, and measures a supply pressure of gas supplied to the combustion chamber; and a determination device that calculates a total air amount supplied to the combustion chamber from a total gas supply amount calculated on the basis of the gas supply pressure, and determines that the blow-by hose is detached from the intake tube when a difference between the total air amount and the fresh air amount exceeds a predetermined amount.

Description

Blow-by hose disconnection detection device

[0001] The present disclosure relates to a blow-by hose disconnection detection device.

[0002] Patent Document 1 discloses that if the PCV piping (blow-by hose) becomes detached from the intake pipe, outside air flows into the intake pipe, reducing the flow rate of air flowing through the intake pipe and also reducing the flow rate of air measured by the air flow meter.

[0003] JP 2010-112287 A

[0004] However, the flow rate of air flowing into the intake pipe varies depending on the operating conditions of the internal combustion engine, such as its rotation speed and torque, so a decrease in the air flow rate measured by the air flow meter does not necessarily mean that the blow-by hose has come off the intake pipe.

[0005] In view of the above circumstances, an object of at least one embodiment of the present invention is to provide a blow-by hose disconnection detection device that can accurately detect disconnection of a blow-by hose.

[0006] (1) A blow-by hose disconnection detection device according to at least one embodiment of the present invention comprises a blow-by hose that returns blow-by gas leaking from a combustion chamber of an internal combustion engine into a crankcase from the crankcase to an intake pipe; a flow sensor that is installed upstream of the connection position of the intake pipe in the intake direction where the blow-by hose is connected and that measures the amount of fresh air taken into the intake pipe; a pressure sensor that is installed downstream of the connection position of the intake pipe in the intake direction and that measures the gas supply pressure supplied to the combustion chamber; and a determination device that calculates the total amount of air to be supplied to the combustion chamber from a total gas supply amount calculated based on the gas supply pressure, and determines that the blow-by hose has come off the intake pipe when the difference between the total air amount and the fresh air amount exceeds a predetermined amount.

[0007] According to the configuration of (1) above, the total amount of air supplied to the combustion chamber is compared with the amount of fresh air supplied to the intake pipe, and if the difference between the total amount of air and the amount of fresh air exceeds a predetermined amount, it is determined that the blow-by hose has come loose from the intake pipe. In this way, the blow-by hose dislodgement detection device determines whether the blow-by hose has come loose, taking into account the operating state of the internal combustion engine, so it can accurately detect whether the blow-by hose has come loose.

[0008] (2) In some embodiments, the configuration of (1) above is provided with an EGR device that recirculates a portion of the exhaust gas discharged from the combustion chamber to the intake pipe, and the EGR device includes an EGR valve that adjusts the amount of exhaust gas to be recirculated to the intake pipe, and a differential pressure acquisition means that acquires the differential pressure between the upstream and downstream sides of the EGR valve, and the determination device calculates the amount of exhaust gas to be supplied to the intake pipe based on the opening degree of the EGR valve and the differential pressure, and determines the total air amount as the amount obtained by subtracting the exhaust gas amount from the total gas supply amount.

[0009] According to the configuration of (2) above, when the internal combustion engine is equipped with an EGR device, the amount of exhaust gas (EGR gas) supplied to the intake pipe is calculated, and the amount obtained by subtracting the amount of exhaust gas from the total gas supply amount is set to the total air amount. In this way, even when the internal combustion engine is equipped with an EGR device, by subtracting the amount of exhaust gas from the total gas supply amount to set the total air amount, it is possible to accurately detect leakage of the blow-by hose.

[0010] (3) In some embodiments, in the configuration of (1) or (2) above, the determination device executes the determination when the rotation speed of the internal combustion engine is equal to or greater than a predetermined rotation speed.

[0011] By setting the predetermined rotation speed to a rotation speed at which the total amount of air supplied to the combustion chamber of the internal combustion engine is stabilized, the amount of fresh air and the gas supply pressure are stabilized. Therefore, according to the configuration (3) above, by setting the predetermined rotation speed to a rotation speed at which the total amount of air supplied to the combustion chamber of the internal combustion engine is stabilized, the determination of whether the blow-by hose has come loose can also be stabilized.

[0012] (4) In some embodiments, the configuration of (3) above includes a supercharging device that supercharges the intake air supplied to the combustion chamber, and the determination device performs the determination when the gas supply pressure is higher than atmospheric pressure.

[0013] When the gas supply pressure is higher than atmospheric pressure, the gas supply pressure is stable. Therefore, according to the configuration (4) above, by executing the above judgment when the gas supply pressure is higher than atmospheric pressure, it is possible to stabilize the judgment as to whether the blow-by hose has come loose.

[0014] (5) In some embodiments, in the configuration of (1) or (2) above, the ratio of the flow area of ​​the blow-by hose to the sum of the flow area of ​​the intake pipe and the flow area of ​​the blow-by hose is greater than the sum of the ratio of the tolerance for the flow rate measured by the flow sensor and the ratio of the tolerance for the pressure measured by the pressure sensor.

[0015] The total amount of air supplied to the combustion chamber fluctuates depending on the flow area of ​​the intake pipe and the flow area of ​​the blow-by hose, so according to the configuration of (5) above, by making the ratio of the flow area of ​​the blow-by hose to the sum of the flow area of ​​the intake pipe and the flow area of ​​the blow-by hose greater than the sum of the ratio of the tolerance for the flow rate measured by the flow sensor and the ratio of the tolerance for the pressure measured by the pressure sensor, it is possible to prevent fluctuations in the amount of fresh air and gas intake pressure from being hidden by the tolerance of the flow sensor and the tolerance of the pressure sensor.

[0016] (6) In some embodiments, in the configuration of (1) or (2) above, the gas supply pressure is the average value of the gas supply pressure measured multiple times, and the fresh air volume is the average value of the fresh air volume measured multiple times at the same time as the gas supply pressure.

[0017] According to the above configuration (6), the gas supply pressure is set to the average value of the gas supply pressure measured multiple times, and the fresh air volume is set to the average value of the fresh air volume measured multiple times at the same timing as the gas supply pressure, so that the flow rate (predetermined amount (threshold value) at which it is determined that the blow-by hose has come out of the intake pipe) can be reduced.

[0018] According to at least one embodiment of the present invention, disconnection of the blow-by hose can be accurately detected.

[0019] 1 is a diagram showing an internal combustion engine according to an embodiment; FIG. 2 is a block diagram showing a configuration of a detection device according to an embodiment; FIG. 3 is a diagram showing the amount of fresh air, the amount of EGR gas, and the amount of blow-by gas, and the total amount of gas supply when EGR gas is introduced, where (a) is a diagram showing the amount of supply in normal times, and (b) is a diagram showing the amount of supply when a blow-by hose is disconnected; FIG. 4 is a diagram showing the amount of fresh air, the amount of blow-by gas, and the total amount of gas supply when EGR gas is cut, where (a) is a diagram showing the amount of supply in normal times, and (b) is a diagram showing the amount of supply when a blow-by hose is disconnected; FIG. 5 is a cross-sectional diagram showing an intake pipe to which a blow-by hose is connected; and FIG. 6 is a flowchart showing a detection procedure of a detection device according to an embodiment.

[0020] Hereinafter, several embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the present invention.

[0021] [Overview of Internal Combustion Engine] Fig. 1 is a diagram that schematically shows an internal combustion engine 1 according to an embodiment. As shown in Fig. 1, the internal combustion engine 1 according to the embodiment is a lean-burn diesel engine in which the amount of air is in excess of the stoichiometric air-fuel ratio, but is not limited thereto and can also be applied to a gasoline engine.

[0022] The internal combustion engine 1 according to the embodiment is provided with a blow-by hose 14 that returns blow-by gas that has leaked from the combustion chamber 11 into the crankcase 12 from the crankcase 12 to the intake pipe 13. One end of the blow-by hose 14 is connected to a head cover 15 where the blow-by gas is concentrated, and the other end is connected to the intake pipe 13.

[0023] The internal combustion engine 1 according to the embodiment includes an EGR device 2 that recirculates a portion of exhaust gas discharged from the combustion chamber 11 (hereinafter referred to as "EGR gas") from the exhaust pipe 16 to the intake pipe 13, and a supercharger 3 that supercharges the intake air supplied to the combustion chamber 11, but these are not essential. The EGR device 2 includes a pipe 21 that recirculates the EGR gas and an EGR cooler 22 provided in the pipe 21, an EGR valve 23 that adjusts the flow rate of exhaust gas recirculated to the intake pipe 13, and a differential pressure sensor 24 (see FIG. 2 ) as differential pressure acquisition means that acquires the differential pressure between the upstream side and the downstream side of the EGR valve 23. The supercharger 3 is a turbocharger that is provided in the middle of the intake pipe 13 and the exhaust pipe 16 and supercharges using exhaust gas, but may also be a supercharger that supercharges using power transmitted from the internal combustion engine 1.

[0024] The internal combustion engine 1 according to the embodiment includes a flow rate sensor 17 that is installed upstream of the connection position of the intake pipe 13 where the blow-by hose 14 is connected in the intake direction and measures the amount of fresh air taken into the intake pipe 13, and a pressure sensor 18 that is installed downstream of the connection position of the intake pipe 13 in the intake direction and measures the pressure of gas supplied to the combustion chamber 11. The flow rate sensor 17 is, for example, an air flow sensor, and the pressure sensor 18 is, for example, a boost pressure sensor.

[0025] The internal combustion engine 1 according to the embodiment is controlled by a control device 4 (hereinafter referred to as the "engine ECU 4"). The engine ECU 4 is configured by, for example, a processor including an arithmetic unit, registers for storing instructions and information, and peripheral devices, memories such as a ROM (Read Only Memory) and a RAM (Random Access Memory), and an input interface, and receives as input the amount of fresh air measured by a flow rate sensor 17 and the gas pressure measured by a pressure sensor 18.

[0026] [Configuration of the Detection Device] Fig. 2 is a block diagram showing a schematic configuration of the detection device 5 according to the embodiment. As shown in Fig. 2, the detection device 5 according to the embodiment is a device that detects when the blow-by hose 14 has come off from the intake pipe 13, and is composed of the blow-by hose 14, a flow rate sensor 17, a pressure sensor 18, and a determination device 41. The determination device 41 is provided in the engine ECU 4, but is not limited to this. The determination device 41 calculates the total amount of air supplied to the combustion chamber 11 from the total gas supply amount calculated based on the gas supply pressure, and determines that the blow-by hose 14 has come off when the difference between the total air amount and the amount of fresh air exceeds a predetermined amount. The predetermined amount is at least greater than the amount of blow-by gas supplied from the blow-by hose 14, and is determined, for example, based on experiments or the like.

[0027] The determination device 41 calculates the amount of exhaust gas (hereinafter referred to as "EGR gas amount") supplied to the intake pipe 13 based on the opening degree of the EGR valve 23 and the differential pressure between the upstream and downstream sides of the EGR valve 23, and determines the total air amount as the amount obtained by subtracting the EGR gas amount from the total gas supply amount.

[0028] [Gas supply amount when EGR gas is introduced] Figure 3 is a diagram showing the amount of fresh air, EGR gas, and blow-by gas when EGR gas is introduced, as well as the total gas supply amount, where (a) is a diagram showing the supply amount under normal conditions, and (b) is a diagram showing the supply amount when the blow-by hose 14 is disconnected from the intake pipe 13.

[0029] 3A, the total gas supply amount during normal EGR gas introduction is composed of the amount of fresh air, the amount of blow-by gas, and the amount of EGR gas. The amount of fresh air is calculated using the flow rate output from the flow rate sensor 17, and the amount of EGR gas is calculated using the opening of the EGR valve 23 and the differential pressure between the upstream and downstream sides of the EGR valve 23. The total gas supply amount is calculated using the flow rate calculated from the pressure output from the pressure sensor 18.

[0030] As shown in Figure 3(b), when the blow-by hose 14 is disconnected from the intake pipe 13, air flows in from the connection position of the blow-by hose 14, so the total gas supply amount when EGR gas is introduced is made up of the amount of fresh air, the amount of inflow air, and the amount of EGR gas, and does not include the amount of blow-by gas.

[0031] Generally, the amount of inflowing air is large enough to be distinguishable from the amount of blow-by gas, so the total air amount is determined by subtracting the amount of EGR gas from the total gas supply amount, and when the difference between the total air amount and the amount of fresh air exceeds a predetermined amount, it can be determined that the blow-by hose 14 has come out of the intake pipe 13. Therefore, as described above, the predetermined amount is at least greater than the amount of blow-by gas supplied from the blow-by hose 14, and is determined, for example, based on an experiment or the like.

[0032] [Gas supply amount when EGR gas is cut] Figure 4 is a diagram showing the amount of fresh air, the amount of blow-by gas, and the total amount of gas supply when EGR gas is cut, where (a) is a diagram showing the amount supplied under normal conditions, and (b) is a diagram showing the amount supplied when the blow-by hose 14 is disconnected from the intake pipe 13.

[0033] As shown in Figure 4(a), the total gas supply amount during EGR gas cutoff is made up of the amount of fresh air and the amount of blow-by gas. As shown in Figure 4(b), when the blow-by hose 14 is disconnected from the intake pipe 13, air flows in from the connection position of the blow-by hose 14, so the total gas supply amount during EGR gas cutoff is made up of the amount of fresh air and the amount of inflowing air, and does not include the amount of blow-by gas.

[0034] Therefore, when EGR gas is cut, the total gas supply amount is set to the total air amount, and when the difference between the total air amount and the fresh air amount exceeds a predetermined amount, it can be determined that the blow-by hose 14 has been detached from the intake pipe 13. In this way, when EGR gas is cut, the total gas supply amount can be set to the total air amount, so that it is possible to accurately determine whether the blow-by hose 14 has been detached.

[0035] In addition, EGR gas is usually cut when the vehicle equipped with the internal combustion engine 1 decelerates and when the diesel particulate filter (DPF) 19 installed in the exhaust pipe 16 is regenerated, but EGR gas may also be cut at a predetermined timing to determine whether the blow-by hose 14 has been disconnected.

[0036]

[0043] The determination device 41 according to the embodiment preferably performs a determination when the rotation speed (rpm) of the internal combustion engine 1 is equal to or greater than a predetermined rotation speed, but is not limited to this. The predetermined rotation speed is a rotation speed at which the amount of fresh air taken into the intake pipe 13 is stable, and is determined by experiment or the like.

[0037] [Gas Supply Pressure Supplied to Combustion Chamber] The determination device 41 according to the embodiment performs a determination when the gas supply pressure supplied to the combustion chamber 11 is higher than atmospheric pressure, but is not limited to this. When the gas supply pressure is higher than atmospheric pressure, the amount of fresh air taken into the intake pipe 13 becomes stable, and the pressure (pressure higher than atmospheric pressure) that serves as the determination index is determined by experiment, etc. The pressure (pressure that serves as the determination index) that is determined by experiment, etc. is, for example, 1.1 times atmospheric pressure, but is not limited to this.

[0038] In the determination device 41 according to the embodiment, it is preferable that the rotation speed of the internal combustion engine 1 is equal to or greater than a predetermined rotation speed and the gas supply pressure is equal to or greater than 1.1 times atmospheric pressure, but if the rotation speed of the internal combustion engine 1 is equal to or greater than a predetermined rotation speed, the gas supply pressure does not have to be equal to or greater than 1.1 times atmospheric pressure, and if the gas supply pressure is equal to or greater than 1.1 times atmospheric pressure, the rotation speed of the internal combustion engine 1 does not have to be equal to or greater than a predetermined rotation speed.

[0039] [Flow path area and sensor accuracy] Figure 5 is a cross-sectional view that shows a schematic view of the intake pipe 13 to which the blow-by hose 14 is connected. As shown in Figure 5, if the pipe diameter of the intake pipe 13 is D and the pipe diameter of the blow-by hose 14 is d, the flow path area of ​​the intake pipe 13 and the flow path area of ​​the blow-by hose 14 are expressed by the following mathematical formula 1.

[0040]

[0041] Fluctuations in the total amount of air supplied to the combustion chamber 11 during EGR gas cut-off are proportional to the flow path cross-sectional area of ​​the intake pipe 13 and the flow path cross-sectional area of ​​the blow-by hose 14. Therefore, it is preferable that the ratio of the flow path area of ​​the blow-by hose 14 to the sum of the flow path area of ​​the intake pipe 13 and the flow path area of ​​the blow-by hose 14 (flow path area of ​​blow-by hose 14 / (flow path area of ​​intake pipe 13+flow path area of ​​blow-by hose 14) is greater than the sum of the ratio of the tolerance for the flow rate measured by the flow sensor 17 and the ratio of the tolerance for the pressure measured by the pressure sensor 18. The sum of the ratio of the tolerance for the flow rate measured by the flow sensor 17 and the ratio of the tolerance for the pressure measured by the pressure sensor 18 is a cumulative tolerance, which can be calculated using the root mean square tolerance.

[0042] The ratio of the flow area of ​​the blow-by hose 14 to the sum of the flow area of ​​the intake pipe 13 and the flow area of ​​the blow-by hose 14 is given by the following equation 2.

[0043]

[0044] [Gas supply pressure and fresh air volume] In the determination device 41 according to the embodiment, it is preferable that the gas supply pressure is the average value of the gas supply pressure measured multiple times, and the fresh air volume is the average value of the fresh air volume measured multiple times at the same timing as the gas supply pressure, but this is not limited to this.

[0045] [Detection Procedure of the Detection Device] Fig. 6 is a flowchart that outlines the detection procedure of the detection device 5 according to the embodiment. As shown in Fig. 6, the detection device 5 according to the embodiment first detects whether the rotation speed of the internal combustion engine 1 is equal to or greater than a predetermined rotation speed (step S11). If the rotation speed of the internal combustion engine 1 is equal to or greater than the predetermined rotation speed (step S11: Yes), the detection device 5 detects whether the gas supply pressure is equal to or greater than 1.1 times the atmospheric pressure (step S12). If the gas supply pressure is equal to or greater than 1.1 times the atmospheric pressure (step S12: Yes), the detection device 5 detects whether EGR gas is being introduced (step S13). If EGR gas is being introduced (step S13: Yes), the determination device 41 calculates the total gas supply amount based on the pressure output from the pressure sensor 18, calculates the EGR gas amount based on the opening degree of the EGR valve 23 and the differential pressure between the upstream and downstream sides of the EGR valve 23 (steps S14 and S15), and calculates the total air amount by subtracting the EGR gas amount from the total gas supply amount (step S16).Then, if the difference between the flow rate (fresh air amount) output from the flow rate sensor 17 and the total air amount exceeds a predetermined amount (step S17: Yes), the determination device 41 determines that the blow-by hose 14 has come off the intake pipe 13 (step S18).

[0046] On the other hand, when the EGR gas is cut (step S13: No), the determination device 41 sets the total gas supply amount calculated based on the pressure output from the pressure sensor 18 as the total air amount (steps S19 and S20).Then, when the difference between the flow rate (amount of fresh air) output from the flow rate sensor 17 and the total air amount exceeds a predetermined amount (step S17: Yes), the determination device 41 determines that the blow-by hose 14 has come off the intake pipe 13 (step S18).

[0047] [Effects of the detection device] The detection device 5 according to the embodiment compares the total amount of air supplied to the combustion chamber 11 with the amount of fresh air supplied to the intake pipe 13, and when the difference between the total amount of air and the amount of fresh air exceeds a predetermined amount, it determines that the blow-by hose 14 has come off from the intake pipe 13. In this way, the detection device 5 determines whether the blow-by hose 14 has come off taking into account the operating state of the internal combustion engine 1, and therefore can accurately detect whether the blow-by hose 14 has come off.

[0048] Furthermore, when the internal combustion engine 1 is equipped with the EGR device 2, the amount of exhaust gas (EGR gas) supplied to the intake pipe 13 is calculated, and the amount obtained by subtracting the amount of exhaust gas from the total gas supply amount is set to the total air amount. In this way, even when the internal combustion engine 1 is equipped with the EGR device 2, by subtracting the amount of exhaust gas from the total gas supply amount to set the total air amount, it is possible to accurately detect leakage of the blow-by hose 14.

[0049] Furthermore, by setting the rotational speed of the internal combustion engine 1 to a rotational speed (a predetermined rotational speed) at which the total amount of air supplied to the combustion chamber 11 of the internal combustion engine 1 is stable, the amount of fresh air and the gas supply pressure are stabilized, and therefore the determination of whether the blow-by hose has come loose can also be stabilized.

[0050] When the gas supply pressure is 1.1 times or more the atmospheric pressure, the gas supply pressure is stable, so by making a judgment when the gas supply pressure is 1.1 times or more the atmospheric pressure, it is possible to stabilize the judgment as to whether the blow-by hose 14 has come off.

[0051] Furthermore, since the total amount of air supplied to the combustion chamber 11 of the internal combustion engine 1 fluctuates depending on the flow area of ​​the intake pipe 13 and the flow area of ​​the blow-by hose 14, by making the ratio of the flow area of ​​the blow-by hose 14 to the sum of the flow area of ​​the intake pipe 13 and the flow area of ​​the blow-by hose 14 greater than the sum of the ratio of the tolerance for the flow rate measured by the flow sensor 17 and the ratio of the tolerance for the pressure measured by the pressure sensor 18, it is possible to prevent fluctuations in the amount of fresh air and gas intake pressure from being hidden by the tolerance of the flow sensor 17 and the tolerance of the pressure sensor 18.

[0052] Furthermore, by setting the gas supply pressure to the average value of the gas supply pressure measured multiple times and setting the fresh air volume to the average value of the fresh air volume measured multiple times at the same timing as the gas supply pressure, it is possible to reduce the flow rate (predetermined amount (threshold value)) at which it is determined that the blow-by hose 14 has come out of the intake pipe 13.

[0053] The present invention is not limited to the above-described embodiment and includes modifications of the above-described embodiment and appropriate combinations of these modifications. For example, in the present embodiment, the differential pressure sensor 24 is used as the differential pressure acquisition means. However, the present invention is not limited to this. The differential pressure between the upstream and downstream sides of the EGR valve 23 may be estimated or indirectly acquired. For example, the pressure upstream of the EGR valve 23 may be estimated from the intake manifold pressure, and the pressure downstream of the EGR valve 23 may be estimated from the exhaust manifold pressure. The intake manifold pressure may be acquired from the output of a boost sensor (a supercharge sensor of the supercharger 3). The exhaust manifold pressure may be calculated by subtracting, from atmospheric pressure, pressure losses of devices provided in the exhaust pipe 16, such as a muffler, a catalyst (such as the DPF 19), and a turbine of the supercharger 3. The atmospheric pressure may be acquired from, for example, an atmospheric pressure sensor provided in the engine compartment. The pressure loss of the catalyst may be acquired from a differential pressure sensor provided in the catalyst. The pressure loss of the turbocharger 3 may be calculated from the flow rate of exhaust gas flowing into the turbine and the turbine rotation speed. The flow rate of exhaust gas may be calculated from the intake air flow rate and the fuel injection amount obtained from the flow rate sensor 17, or may be obtained by providing an exhaust gas flow rate sensor that obtains the exhaust gas flow rate.

[0054] REFERENCE SIGNS LIST 1 internal combustion engine 11 combustion chamber 12 crankcase 13 intake pipe 14 blow-by hose 15 head cover 16 exhaust pipe 17 flow sensor 18 pressure sensor 19 diesel particulate filter (DPF) 2 EGR device 21 piping 22 EGR cooler 23 EGR valve 24 differential pressure sensor 3 supercharging device 4 control device (engine ECU) 41 determination device 5 detection device

Claims

1. A blow-by hose dislodgement detection device comprising: a blow-by hose that returns blow-by gas that has leaked from the combustion chamber of an internal combustion engine into the crankcase from the crankcase to an intake pipe; a flow sensor that is installed upstream in the intake direction of the intake pipe from a connection position where the blow-by hose is connected, and measures the amount of fresh air taken into the intake pipe; a pressure sensor that is installed downstream in the intake direction of the intake pipe from the connection position, and measures the gas supply pressure supplied to the combustion chamber; and a determination device that calculates the total amount of air to be supplied to the combustion chamber from a total gas supply amount calculated based on the gas supply pressure, and determines that the blow-by hose has dislodged from the intake pipe when the difference between the total air amount and the fresh air amount exceeds a predetermined amount.

2. A blow-by hose disconnection detection device as described in claim 1, comprising an EGR device that recirculates a portion of the exhaust gas discharged from the combustion chamber into the intake pipe, the EGR device including: an EGR valve that adjusts the amount of exhaust gas to be recirculated into the intake pipe; and a differential pressure acquisition means that acquires the differential pressure between the upstream and downstream sides of the EGR valve, and the determination device calculates the amount of exhaust gas to be supplied to the intake pipe based on the opening of the EGR valve and the differential pressure, and determines the total air amount as the amount obtained by subtracting the exhaust gas amount from the total gas supply amount.

3. A blow-by hose disconnection detection device according to claim 1 or 2, wherein the determination device executes the determination when the rotation speed of the internal combustion engine is equal to or greater than a predetermined rotation speed.

4. A blow-by hose disconnection detection device as described in claim 3, further comprising a supercharging device that supercharges the intake air supplied to the combustion chamber, and the determination device performs the determination when the gas supply pressure is higher than atmospheric pressure.

5. A blow-by hose disconnection detection device as described in claim 1 or 2, wherein the ratio of the flow area of ​​the blow-by hose to the sum of the flow area of ​​the intake pipe and the flow area of ​​the blow-by hose is greater than the sum of the ratio of the tolerance for the flow rate measured by the flow sensor and the ratio of the tolerance for the pressure measured by the pressure sensor.

6. A blow-by hose disconnection detection device as described in claim 1 or 2, wherein the gas supply pressure is the average value of the gas supply pressure measured multiple times, and the fresh air volume is the average value of the fresh air volume measured multiple times at the same time as the gas supply pressure.

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