JP2018131954A - Abnormality detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an abnormality detector capable of detecting abnormality of PM accumulation with high accuracy.SOLUTION: An abnormality detector includes: a detection unit configured to detect abnormality of particulate matter accumulation in a case where an accumulation amount of the particulate matter per unit distance to a filter is within a predetermined range, the filter configured to collect the particulate matter in exhaust of a vehicle; and a range determination unit configured to change a range between a case where the accumulation amount of the particulate matter per unit time is not larger than a first accumulation amount and a case where it is larger than the first accumulation amount.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an abnormality detection device.

  In automobiles, particulate matter (PM) in exhaust gas exhausted from an internal combustion engine is collected, for example, diesel particulate filter (DPF) or gasoline particulate filter (GPF). ) Is used. When the amount of PM deposited on the filter increases, the pressure loss increases and the drivability deteriorates. For this reason, when the accumulation amount reaches a predetermined amount, filter regeneration for removing PM by burning may be performed (see, for example, Patent Document 1).

JP 7-34854 A

  If the PM deposition rate is abnormally high, the driver may be notified, for example, by turning on a warning light. However, since the PM deposition rate varies depending on the vehicle speed, it is difficult to detect an abnormality with high accuracy. In view of this, an object of the present invention is to provide an abnormality detection device capable of detecting PM accumulation abnormality with high accuracy.

  The object is to detect abnormal accumulation of particulate matter when the amount of particulate matter deposited per unit distance to a filter that collects particulate matter in vehicle exhaust is within a predetermined range. A detection unit, and a range determination unit that makes the range different depending on whether the amount of the particulate matter deposited per unit time is less than or equal to the first deposition amount and when the deposition amount is larger than the first deposition amount; It can achieve by the abnormality detection apparatus which comprises.

  It is possible to provide an abnormality detection device capable of detecting PM accumulation abnormality with high accuracy.

FIG. 1 is a schematic view illustrating an internal combustion engine. FIG. 2 is a flowchart illustrating a process performed by the ECU. FIG. 3 is a schematic diagram showing a map using the deposition rate.

(First embodiment)
Hereinafter, the abnormality detection apparatus of the present embodiment will be described with reference to the drawings. FIG. 1 is a schematic view illustrating an internal combustion engine 100. The internal combustion engine 100 is, for example, a diesel engine or a gasoline engine mounted on an automobile or the like, and an abnormality detection device is applied to the internal combustion engine 100.

  As shown in FIG. 1, an intake pipe 12 is connected to an intake port of an engine body 10 of the internal combustion engine 100, and an exhaust pipe 14 is connected to an exhaust port. The engine body 10 is provided with an intake valve Vi that opens and closes an intake port and an exhaust valve Ve that opens and closes an exhaust port.

  The intake pipe 12 is provided with an air cleaner 16, an air flow meter 18 for detecting the intake air amount, a throttle valve 20, and an injector 22 in order from the upstream side. The injector 22 is provided on the downstream side of the intake pipe 12. The fuel injected from the injector 22 is mixed with intake air to form an air-fuel mixture. This air-fuel mixture is sucked into the combustion chamber 10a of the engine body 10 when the intake valve Vi is opened, compressed by the piston 32, and burned. The crank angle sensor 31 detects the crank angle.

  Exhaust gas generated by combustion in the engine body 10 is discharged from the exhaust pipe 14 to the outside of the vehicle. The exhaust pipe 14 is provided with an air-fuel ratio sensor 33 and a filter 34. The air-fuel ratio sensor 33 detects the air-fuel ratio. The filter 34 is, for example, DPF or GPF, and purifies the exhaust gas by collecting particulate matter (PM) in the exhaust gas. Further, the exhaust pipe 14 may be provided with a filter 34 and a catalyst for purifying exhaust gas.

  The ECU (Engine Control Unit, abnormality detection device) 40 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and a storage device. The ECU 40 performs various controls by executing a program stored in the ROM or the storage device. The ECU 40 is electrically connected to an air flow meter 18, a throttle valve 20, an injector 22, a crank angle sensor 31, and an air / fuel ratio sensor 33.

  The ECU 40 acquires the vehicle speed and the PM deposition rate on the filter 34. The deposition rate is a deposition amount per unit distance (for example, g / km) and a deposition amount per unit time (for example, g / h). Here, for example, the distance is the travel distance of the vehicle, and the time is the travel time of the vehicle. The ECU 40 can acquire the deposition rate based on, for example, the differential pressure on the upstream side and the downstream side of the filter 34 of the exhaust pipe 14, or may be acquired by other methods. The ECU 40 determines that PM deposition on the filter 34 is abnormal when the deposition rate is within a predetermined range. In addition, the ECU 40 varies the range that is a criterion for determination. That is, the ECU 40 functions as an abnormality detection unit and a range determination unit.

  FIG. 2 is a flowchart illustrating a process performed by the ECU 40 and is performed at predetermined time intervals when the vehicle is traveling.

  As shown in FIG. 2, the ECU 40 acquires the PM deposition rate (deposition amount V1 per unit distance) on the filter 34 (step S1). Further, the ECU 40 acquires the PM deposition rate (deposition amount V2 per unit time) (step S2).

  In FIG. 2, the ECU 40 determines whether or not the deposition rate V1 is greater than a deposition rate Vth1 that is a threshold value (step S3). In the case of an affirmative determination, the ECU 40 determines whether or not the deposition rate V2 is equal to or less than a deposition rate Vth2 (first deposition amount) that is a threshold value (step S4). If the determination is affirmative, the ECU 40 determines that PM accumulation on the filter 34 is abnormal (step S6). On the other hand, if a negative determination is made in step S3, the ECU 40 determines that the accumulation of PM on the filter 34 is normal (step S7).

  If a negative determination is made in step S4, the ECU 40 determines whether or not the deposition rate V1 is greater than a deposition rate Vth3 that is a threshold value (step S5). This threshold value Vth3 is larger than Vth1. If the determination is affirmative, the ECU 40 determines that PM accumulation on the filter 34 is abnormal (step S6). On the other hand, if a negative determination is made in step S5, the ECU 40 determines that the accumulation of PM on the filter 34 is normal (step S7).

  The processing will be described in detail with reference to FIG. FIG. 3 is a schematic diagram showing a map using the deposition rate. The horizontal axis represents the deposition amount per unit travel distance (deposition rate V1), and the vertical axis represents the deposition amount per unit time (deposition rate V2).

  A range A in FIG. 3 is a region where the deposition amount per unit time is small in the deposition amount per unit travel distance (deposition speed V1). That is, the range A corresponds to a process when the vehicle is traveling at a low speed, and the ECU 40 determines that the filter 34 is abnormal. That is, when V1 is larger than Vth1 and V2 is Vth2 or less, the ECU 40 determines that there is an abnormality (step S6 in FIG. 2). On the other hand, the range B is a region where the deposition amount per unit time is larger than the range A in the deposition amount per unit travel distance (deposition speed V1). That is, the range B corresponds to a process when the vehicle is traveling at high speed, and the ECU 40 determines that the filter 34 is abnormal. That is, when V1 is larger than Vth3 and V2 is larger than Vth2, ECU 40 determines that there is an abnormality (step S6 in FIG. 2).

  The amount of PM discharged, the amount deposited on the filter 34, and the like vary depending on the speed of the vehicle. For example, when the vehicle speed increases, the PM deposition rate per unit time also increases. For this reason, for example, if the abnormality of the filter 34 is determined using a threshold value corresponding to low-speed traveling, the accuracy may decrease during high-speed traveling, and an erroneous determination may be made. In addition, when there is an abnormality in the accumulation, the accumulation amount on the filter 34 may reach the limit early, and exhaust emission, fuel consumption, oil dilution, and the like may occur.

  According to the first embodiment, as shown in FIG. 3, the ECU 40 detects an accumulation abnormality when the accumulation amount per unit distance is within a predetermined range, and according to the accumulation amount per unit time. Range can be different. In other words, the ECU 40 makes a determination using different ranges for the PM deposition speed in one map (FIG. 3) during low speed traveling and during high speed traveling. That is, when traveling at a low speed, the ECU 40 determines that PM accumulation is abnormal in the range A where Vth1 <V1 and V2 ≦ Vth2 (FIGS. 2 and 3). When traveling at high speed, the ECU 40 determines that there is an abnormality in the range B where Vth3 <V1 and Vth2 <V2. As a result, highly accurate detection is possible by using one map. The ECU 40 preferably notifies the driver by turning on a warning light, for example. The driver who has received the notification performs maintenance of the vehicle, for example, so that the filter 34 is in an appropriate state, and exhaust emission, fuel consumption deterioration, oil dilution, and the like are suppressed.

  In this embodiment, two threshold values Vth1 and Vth3 are used for V1, and one threshold value Vth2 is used for V2. For example, two threshold values may be used for V2, and three or more threshold values may be used for V1.

  Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It can be changed.

DESCRIPTION OF SYMBOLS 10 Engine main body 10a Combustion chamber 12 Intake pipe 14 Exhaust pipe 16 Air cleaner 18 Air flow meter 20 Throttle valve 22 Injector 31 Crank angle sensor 32 Piston 33 Air-fuel ratio sensor 34 Filter 40 ECU
100 Internal combustion engine

Claims (1)

A detection unit for detecting abnormal accumulation of the particulate matter when a deposition amount of the particulate matter per unit distance to a filter that collects the particulate matter in the exhaust of the vehicle is within a predetermined range;
An abnormality comprising: a range determining unit that varies the range depending on whether the amount of the particulate matter deposited per unit time is equal to or less than the first deposition amount and greater than the first deposition amount. Detection device.

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