JP2010196498A - Pm emission estimation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a PM (Particulate Matter) emission estimation device obtaining high-precision estimated PM emission approximated to the actual PM emission discharged from an engine so that excessive accumulation of ash or PM is prevented. <P>SOLUTION: This PM emission estimation device includes an intake air temperature sensor, an airflow meter, a DPF (Diesel Particulate Filter), an estimated PM emission calculation means, and a PM calculated reference amount storage means, and estimates PM emission based on detected temperature, detected intake air volume and PM calculated reference amount. In the PM emission estimation device, a differential pressure sensor and an ash deposited amount calculation means are provided. The ash deposited amount calculation means calculates the amount of ash deposited based on detected differential pressure. The estimated PM emission calculation means calculates estimated PM emission discharged from the engine based on PMe=PMb×Kth×Keq×Kash, where PMb represents PM calculated reference amount, Kth represents a temperature correction coefficient, Keq represents an intake air volume correction coefficient, Kash represents an ash deposited amount correction coefficient, and PMe represents estimated PM emission. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a PM emission amount estimation device that estimates the emission amount of PM discharged from an engine with high accuracy.

  In general, the exhaust gas discharged from the engine contains harmful substances that are not preferably discharged to the atmosphere as they are, and in particular, the exhaust gas discharged from the diesel engine contains particulate matter (PM). Matter), soot (SOOT), soluble organic components (SOF), ash composed of incombustible components (ASH), and other harmful substances are included, and the emission of these harmful substances causes air pollution. . In order to purify such harmful substances, for example, a diesel particulate filter (DPF: Diesel Particulate Filter) that collects PM in exhaust gas flowing through the exhaust passage of a diesel engine is provided in the exhaust passage.

  In the case of such a DPF, if PM exceeding the allowable amount is collected in the DPF, the DPF is clogged and the exhaust resistance increases, which may cause a deterioration in the fuel consumption rate (g / KWh). Arise. In addition, there is a risk that the catalyst for purifying the exhaust gas and the DPF may be melted. Therefore, the PM accumulated in the DPF is heated to about 600 ° C., for example, at a stage where a certain amount of PM is collected in the DPF so that normal operation of the diesel engine is not hindered. PM regeneration treatment is performed in which an oxidation reaction is caused to oxidize and remove. This PM regeneration process is desirably performed at a timing when the amount of PM trapped in the DPF reaches an appropriate amount. For this purpose, it is necessary to accurately grasp the amount of PM accumulated in the DPF and the amount of PM discharged from the engine. For diesel engines, the amount of PM accumulation is estimated accurately. An apparatus and a PM emission amount estimation device for accurately estimating the PM emission amount are provided.

Conventionally, as this kind of PM accumulation amount estimation device, a DPF that is installed in an exhaust passage of a diesel engine and collects PM in exhaust gas, and a control for regenerating the DPF by burning the accumulated PM. A regeneration control means for performing, a regeneration end judging means for judging that the DPF has been regenerated, and a filter front-rear differential pressure detection for detecting a differential pressure before and after the filter, which is a differential pressure before and after the filter, immediately after it is determined that the filter has been regenerated. And an ash accumulation amount estimation means for estimating an ash accumulation amount that is an amount of ash accumulated on the DPF based on the detected differential pressure across the filter. For example, see Patent Document 1).
In this PM accumulation amount estimation device, accumulation in the DPF is performed based on a PM accumulation amount map corresponding to the engine speed and engine load, and a history of engine operating conditions, for example, a history of changes in engine speed and engine load. The amount of accumulated PM, which is the amount of PM deposited, is obtained, and this PM accumulation amount is corrected by the ash accumulation amount estimated by the ash accumulation amount estimating means, and a value closer to the actual PM accumulation amount is estimated. Like to do.

The ash deposition amount, which is the only correction means for the PM deposition amount, is estimated as follows. That is, at the time when the DPF is to be regenerated, control for burning the accumulated PM is performed, and immediately after it is determined that the DPF has been regenerated, the differential pressure before and after the filter is detected. The ash accumulation amount is estimated based on the differential pressure.
By estimating the ash accumulation amount based on the differential pressure before and after the filter immediately after the regeneration of the DPF, the ash accumulation amount can be accurately estimated without requiring correction for differences in engine oil consumption and its type. Therefore, the PM deposition amount is estimated by the accurate ash deposition amount.

  Further, as this type of PM emission amount estimation device, for example, an intake air temperature sensor that detects the temperature of intake air sucked into the engine, an air flow meter that detects the amount of intake air sucked into the engine, and an exhaust passage of the engine A PM collection filter serving as a DPF that collects PM discharged from the engine that is disposed in the engine, an estimated PM accumulation amount calculating means that calculates an estimated PM accumulation amount in the PM collection filter, and an estimated PM accumulation amount PM calculation reference amount storage means for storing a PM calculation reference amount serving as a calculation reference for the estimated PM accumulation amount calculated by the calculation means, and a detected temperature detected by an intake air temperature sensor and detected by an air flow meter A device that estimates the amount of PM discharged from an engine based on a detected intake air amount and a PM calculation reference amount is known.

  In this PM discharge amount estimation device, the PM calculation reference amount is multiplied by a temperature correction coefficient for correcting the PM calculation reference amount with the detected temperature and an intake air amount correction coefficient for correcting the PM calculation reference amount with the intake air amount. Thus, the estimated amount of accumulated PM is calculated.

JP 2004-21650 A

  However, in the conventional PM accumulation amount estimation device described in Patent Document 1, the ash estimated by the ash accumulation amount estimation unit is obtained with respect to the PM accumulation amount obtained based on the history of changes in the engine speed and the engine load. Since a value close to the actual PM deposition amount is estimated by correcting only with the deposition amount, there is a problem that it cannot always be said that a highly accurate estimated PM deposition amount can be obtained. That is, the amount of PM accumulated in the DPF is affected by the temperature of the intake air sucked into the engine and the amount of intake air sucked into the engine. However, there is a limit to the correction, and the estimated PM deposition amount varies depending on the temperature of the intake air and the amount of intake air. The PM accumulation amount estimation device can obtain a highly accurate estimated PM deposition amount. There wasn't.

  Further, in the conventional PM emission amount estimation device, the estimated PM accumulation is obtained by multiplying the PM calculation reference amount by the temperature correction coefficient corrected by the temperature and the intake air amount correction coefficient corrected by the intake air amount. Since the amount is corrected and calculated, there is a problem that it is not always possible to obtain a highly accurate estimated PM deposition amount. That is, in other PM emission amount estimation devices, although the PM calculation reference amount is corrected by the temperature correction coefficient and the intake air amount correction coefficient, it is insufficient for an engine that performs intake control.

  In an engine that performs intake control, for example, an EGR (Exhaust Gas Recirculation) device is provided, and an external EGR obtained by adjusting the amount of exhaust gas discharged from the engine and the amount of intake air to a predetermined ratio by an EGR valve. The electronic control unit (ECU: Electronic Control) so that the internal EGR rate obtained by advancing or retarding the valve timing of the intake valve or the like by the variable valve timing mechanism (VVT) becomes a predetermined target value. Unit). In this case, by adjusting the external EGR rate to the target value, variations in nitrogen oxides (Nox: Nitrogen Oxide x) discharged from the engine are suppressed. Therefore, when ash or PM is excessively accumulated, the back pressure in the exhaust passage increases, the external EGR rate and the internal EGR rate change, the charging efficiency of intake air changes, and target combustion cannot be obtained. Since the PM emission amount is larger than when no ash is accumulated, there is a problem that the PM emission amount cannot be estimated accurately.

  The present invention solves the above-mentioned conventional problems, and obtains a highly accurate estimated PM emission amount that approximates the actual PM emission amount discharged from the engine so as to prevent over-deposition of ash and PM. It is an object of the present invention to provide a PM emission amount estimation device.

  In order to achieve the above object, the PM emission estimation device according to the present invention detects (1) an intake air temperature sensor that detects the temperature of intake air sucked into the engine and a temperature of cooling water that cools the engine. A cooling water temperature sensor; an air flow meter for detecting an intake air amount sucked into the engine; an estimated PM discharge amount calculating means for calculating an estimated discharge amount of PM composed of particulate matter discharged from the engine; PM calculation reference amount storage means for storing a PM calculation reference amount that is a calculation reference for the estimated PM discharge amount calculated by the PM discharge amount calculation means, and at least one of the intake air temperature sensor and the cooling water temperature sensor Based on the detected temperature detected by one, the detected intake air amount detected by the air flow meter, and the PM calculation reference amount, In the PM emission amount estimation device that estimates the discharged PM emission amount, the pressure of the exhaust gas in the exhaust passage upstream of the PM collection filter that is disposed in the exhaust passage of the engine and collects PM, and the PM trapping. A differential pressure sensor for detecting a difference from the pressure of the exhaust gas in the exhaust passage on the downstream side of the collecting filter, an engine oil supply amount calculating means for calculating a supply amount of the engine oil supplied to the engine, and the engine Ash accumulation amount calculating means for calculating an ash accumulation amount composed of incombustible components discharged from the engine, wherein the PM calculation reference amount is an injection amount of fuel injected into the engine, an engine load, and the engine Comprising a reference amount obtained from a map created based on at least one of the torques output from the ash accumulation amount calculating means The ash accumulation amount is calculated based on at least one of the differential pressure detected by the differential pressure sensor and the engine oil supply amount calculated by the engine oil supply amount calculation means, and the estimated PM discharge amount calculation means The PM calculation reference amount is PMb, the temperature correction coefficient for correcting the PM calculation reference amount PMb by the detected temperature is Kth, and the intake air amount correction coefficient for correcting the PM calculation reference amount PMb by the detected intake air amount Is Keq, an ash accumulation amount correction coefficient for correcting the PM calculation reference amount PMb based on the ash accumulation amount calculated by the ash accumulation amount calculating means is Kash, and an estimated PM emission amount discharged from the engine is PMe. Based on the following formula, PMe = PMb × Kth × Keq × Kash, the estimated PM discharge An amount is calculated.

With this configuration, it is possible to obtain a highly accurate estimated PM discharge amount that approximates the actual PM discharge amount discharged from the engine, thereby preventing ash and PM from being excessively deposited.
That is, in the conventional PM discharge amount estimation device, a temperature correction coefficient for correcting the PM calculation reference amount with the detected temperature and an intake air amount correction coefficient for correcting the PM calculation reference amount with the intake air amount are used as the PM calculation reference amount. On the other hand, in the PM emission amount estimation device according to the present invention, the PM calculation reference amount is further multiplied by the ash accumulation amount correction coefficient Kash to calculate the PM. The reference amount is corrected. As a result, the estimated PM deposition amount in the past remained almost constant linearly despite the increase in the ash deposition amount, whereas the obtained estimated PM deposition amount was almost the actual actual emission amount. An effect of obtaining an approximate and highly accurate value is obtained. That is, the difference between the conventional estimated PM accumulation amount and the actual actual emission amount is remarkably reduced, and the difference between the estimated PM accumulation amount and the actual actual emission amount is improved.

  Further, since the difference between the estimated PM accumulation amount and the actual actual discharge amount is remarkably small, fine PM regeneration interval control can be performed in the PM regeneration processing, and the risk of DPF erosion is reduced. Clogging is prevented in advance and an increase in exhaust resistance is suppressed, so that deterioration of the fuel consumption rate (g / KWh) is suppressed.

  According to the present invention, there is provided a PM emission amount estimation device capable of obtaining a highly accurate estimated PM emission amount approximate to an actual PM emission amount discharged from an engine so as to prevent ash and PM from being excessively accumulated. be able to.

1 is a configuration diagram of a diesel engine to which a PM emission amount estimation device according to a first embodiment of the present invention is applied. 1 is a perspective view of an air flow meter provided in an intake pipe of a diesel engine to which a PM emission amount estimation device according to a first embodiment of the present invention is applied. It is sectional drawing of the exhaust-gas aftertreatment apparatus provided in the exhaust pipe of the diesel engine to which PM emission amount estimation apparatus which concerns on the 1st Embodiment of this invention is applied. (A) is a temperature correction map by the cooling water temperature in the PM discharge amount estimation apparatus according to the first embodiment of the present invention, and (b) is a temperature correction map by the intake air temperature. It is an intake air amount correction map in the PM discharge amount estimation device according to the first embodiment of the present invention. It is an engine oil supply amount correction map in the PM emission amount estimation device according to the first embodiment of the present invention. It is an ash deposition amount correction map in the PM emission amount estimation device according to the first embodiment of the present invention. It is a flowchart which shows the calculation process of the estimated PM discharge amount in the PM discharge amount estimation apparatus which concerns on the 1st Embodiment of this invention. It is explanatory drawing which shows the relationship between the travel distance of a vehicle and the differential pressure | voltage of DPF in the PM emission amount estimation apparatus which concerns on the 1st Embodiment of this invention. It is explanatory drawing which shows the relationship between the ash deposition amount and PM discharge | emission amount in the PM discharge | emission amount estimation apparatus which concerns on the 1st Embodiment of this invention. (A) is a graph which shows the conventional PM reproduction | regeneration interval, (b) is a graph which shows PM reproduction | regeneration interval in the PM emission amount estimation apparatus which concerns on the 1st Embodiment of this invention. It is a differential pressure value map in the PM discharge amount estimation device according to the second embodiment of the present invention. It is a flowchart which shows the calculation process of the estimated PM discharge amount in the PM discharge amount estimation apparatus which concerns on the 2nd Embodiment of this invention.

  Hereinafter, a first embodiment and a second embodiment of a PM emission amount estimation device according to the present invention will be described with reference to the drawings.

(First embodiment)
First, the configuration will be described.
The PM emission amount estimation device 2 according to the first embodiment constitutes a part of a diesel engine 1 mounted on a vehicle. The engine of this vehicle may be an engine other than the diesel engine 1, for example, an engine using a liquid such as gasoline or ethanol as fuel. The specification of the diesel engine is arbitrarily selected. For example, the diesel engine 1 is composed of a known diesel engine such as an in-line four cylinder.

  Specifically, as shown in FIG. 1, the diesel engine 1 includes a PM emission amount estimation device 2 and a part of the PM emission amount estimation device 2, and is an electronic control unit that controls the diesel engine 1 ( ECU: Electronic Control Unit) 3, engine body 4, fuel supply device 5 for supplying fuel to engine body 4, intake pipe 6, air cleaner 7 provided in intake pipe 6, intercooler 8, and throttle valve 9, an exhaust pipe 11, an EGR (Exhaust Gas Recirculation) device 12 that recirculates part of the exhaust gas discharged from the engine body 4 into the intake pipe 6, and an exhaust gas aftertreatment device provided in the exhaust pipe 11 13 and a turbocharger 14.

  The PM emission amount estimation device 2 includes an estimated PM emission amount calculation means, a PM calculation reference amount storage means, an engine oil supply amount calculation means, an ash accumulation amount calculation means, and an intake air temperature sensor 21 that constitute a part of the ECU 3. A cooling water temperature sensor 22, an air flow meter 23, a differential pressure sensor 24, an exhaust temperature sensor 25, and a crank position sensor 26.

  The PM emission amount estimation device 2 is discharged from the diesel engine 1 by the execution of the estimated PM emission amount calculation means, the PM calculation reference amount storage means, the engine oil supply amount calculation means, and the ash accumulation amount calculation means by the ECU 3. The estimated PM emission amount (g) is calculated with high accuracy, and the calculated estimated PM emission amount is notified to the ECU 3.

  The intake air temperature sensor 21 includes, for example, a compact type thermistor, is built in the air flow meter 23, detects the temperature (° C.) of intake air passing through the air flow meter 23, and is input to the ECU 3 as a temperature signal. Input to the interface circuit.

  The coolant temperature sensor 22 includes, for example, a thermistor having excellent temperature characteristics. The thermistor is connected to the ECU 3, detects a resistance value corresponding to the temperature of the cooling water for cooling the diesel engine 1, and inputs a voltage signal to the input interface circuit of the ECU 3. The cooling water temperature sensor 22 is mounted in the engine body 4 around the cylinder so as to detect the temperature of the coolant that has flowed around the cylinder of the engine block of the engine body 4 and has been heated.

  As shown in FIG. 2, the air flow meter 23 is composed of, for example, a hot wire type air flow meter, and a bridge circuit is configured by a resistance 23 o for measuring the intake air temperature and a heating resistance 23 k, and an intake air amount (g / When rev) changes, the bridge circuit is configured to feedback control the power supplied to the heating resistor 23k so that the temperature difference between the intake temperature measuring resistor 23o and the heating resistor 23k is always kept constant. This supplied power is converted into a voltage, and a detected intake air amount (g / rev) as an intake air amount signal is output to the ECU 3. The air flow meter 23 is attached to the intake pipe 6 so that the resistance 23o for measuring the intake air temperature and the heating resistance 23k are exposed in the intake passage.

  The differential pressure sensor 24 is composed of, for example, a pressure sensor in which an electric circuit such as a strain gauge is arranged on a pressure detection member such as a diaphragm, and detects the pressure (kPa) of the exhaust gas upstream of the exhaust gas aftertreatment device 13. An upstream pressure detection unit 24j, a downstream pressure detection unit 24k that detects the pressure (kPa) of exhaust gas downstream of the exhaust gas aftertreatment device 13, and a differential pressure detection circuit unit 24s are configured. The differential pressure (kPa) detected by the differential pressure detection circuit unit 24s is configured to be input to the input interface circuit of the ECU 3.

  The exhaust temperature sensor 25 includes, for example, a temperature sensor element having two thermocouples, is attached to the exhaust gas aftertreatment device 13, and the temperature (° C.) of the exhaust gas passing through the exhaust gas aftertreatment device 13. ) And is input to the input interface circuit of the ECU 3 as a temperature signal. The exhaust temperature sensor 25 may be attached to two locations of the exhaust gas aftertreatment device 13 to increase the accuracy of the detected temperature.

  The crank position sensor 26 includes, for example, a timing rotor fixed to a crankshaft (not shown) and an electromagnetic pickup sensor, and is fixed to the engine block 31 of the engine body 4. The crank position sensor 26 detects a crank rotation signal such as a crank position and a crank angular velocity, and the detected signal is input to an input interface circuit of the ECU 3.

  The ECU 3 includes engine start determination means, estimated PM emission amount calculation means constituting the PM emission amount estimation device 2, PM calculation reference amount storage means, engine oil supply amount calculation means, and ash accumulation amount calculation means. Yes. In the ECU 3, the operation of each means is continuously executed by a single or a plurality of programs.

  Specifically, the ECU 3 includes a CPU (Central Processing Unit), an engine start determination unit, an estimated PM emission amount calculation unit, a PM calculation reference amount storage unit, an engine oil supply amount calculation unit, and an ash accumulation amount calculation unit. ROM (Read Only Memory) in which programs for executing operations, PM calculation reference amounts, etc. are stored, RAM (Random Access Memory) in which data is temporarily stored, EPROM (non-volatile memory that can be electrically rewritten) Electrically Erasable and Programmable Read Only Memory), an input interface circuit such as an A / D converter and a buffer, and an output interface circuit.

Intake temperature sensor 21, cooling water temperature sensor 22, air flow meter 23, differential pressure sensor 24, exhaust temperature sensor 25, crank position sensor 26, oil pressure sensor (not shown), throttle opening sensor, accelerator position sensor, air-fuel ratio sensor, O ₂ Sensors such as sensors are respectively connected to the input interface circuit of the ECU 3, and information output from these sensors is taken into the ECU 3 through the input interface circuit.

  In the ECU 3, the engine rotational speed Ne (rpm) is obtained based on information input from a sensor that detects the rotational speed (rpm) of the crankshaft such as the crank position sensor 26. Further, the ECU 3 calculates the intake air amount from the relationship between the preset output voltage of the air flow meter 23 and the flow rate of the intake air, based on the intake air amount signal input from the air flow meter 23. The input information of each sensor is converted into necessary data.

  The engine start determination means of the ECU 3 is configured to determine whether or not the diesel engine 1 has been started. For example, it detects that the starter switch for operating the starter motor of the diesel engine 1 is turned on, or the starter When it is detected that it is less than a predetermined time after the switch is switched from on to off, it is determined that the diesel engine 1 has been started.

  If neither is detected, the engine start determination means of the ECU 3 is configured to monitor the starter switch on or off at predetermined time intervals until it is determined that the diesel engine 1 has been started. The predetermined time interval is appropriately selected based on the characteristics of the PM emission amount estimation device 2 and the diesel engine 1, the vehicle type, and the like. For example, a predetermined time interval may be set as appropriate, from the start of operation to the end of operation. Any time interval appropriately selected may be used.

  The estimated PM emission amount calculation means of the ECU 3 is configured to calculate the estimated PM emission amount discharged from the diesel engine 1.

Specifically, in the estimated PM emission amount calculation means of the ECU 3, a PM emission estimation base that is a calculation reference for the estimated PM emission amount (g) calculated by the estimated PM emission amount calculation means, that is, a PM calculation reference amount ( g) is set to PMb, and a temperature correction coefficient for correcting the PM calculation reference amount PMb (g) based on the detected temperature (° C.) of at least one of the intake air temperature sensor 21 and the cooling water temperature sensor 22 is set to Kth. The intake air amount correction coefficient for correcting the PM calculation reference amount PMb (g) based on the detected intake air amount (g / rev) is Keq, and the PM calculation reference amount is calculated based on the ash accumulation amount (g) calculated by the ash accumulation amount calculation means. The ash accumulation amount correction coefficient for correcting PMb (g) is Kash, and the estimated PM emission amount (g) discharged from the diesel engine 1 is P. When e, based equation, PMe = PMb × Kth × Keq × Kash, the estimated PM emission amount (g) is calculated.
Here, g in the unit (g / rev) of the detected intake air amount represents mass, and rev represents a crank angle of 360 degrees, that is, one rotation of the crankshaft.

  Specifically, the PM calculation reference amount (g) PMb, which serves as a PM emission estimation base, is prepared in advance based on the engine speed Ne (rpm) and the fuel injection amount qfin (g) and stored in the ROM of the ECU 3. An engine load map created in advance based on a quantity map, an engine speed Ne (rpm) and an engine load and stored in the ROM of the ECU 3, an engine speed Ne (rpm) and a torque (N · m). It is determined based on a value (g) obtained from a map such as a torque map stored in the ROM of the ECU 3.

  The fuel injection amount qfin is determined by a basic injection amount (g) stored in advance in the ROM of the ECU 3 and various corrections for this basic injection amount. The basic injection amount is calculated from input information of intake air supplied to the diesel engine 1 such as an intake air amount (g / rev) and supplied fuel. Examples of the various corrections include post-startup increase correction, intake air temperature correction, output increase correction, fuel ratio feedback correction, fuel cut correction, and the like.

  The engine load is obtained by the ECU 3 based on the engine load information input to the ECU 3. The engine load information includes, for example, an output signal of the intake air temperature (° C.) of the intake air temperature sensor 21 and a cooling water temperature sensor. 22, an output signal of the cooling water temperature (° C.), an output signal of the detected intake air amount (g / rev) of the air flow meter 23, an output signal of the differential pressure (kPa) of the differential pressure sensor 24, and an exhaust temperature of the exhaust temperature sensor 25 ( ° C) output signal, crank rotation output signal of the crank position sensor 26, pressure sensor suction air pressure (kPa) and oil pressure sensor detection pressure (kPa) output signal, accelerator position sensor accelerator opening ACC output signal , Output signal of throttle opening of throttle sensor, output signal of lubricating oil temperature (° C) of oil temperature sensor, fuel pressure of fuel pressure sensor (k The output signal of a), includes information comprising a respective output signal such.

  The torque (N · m) represents the torque output from the diesel engine 1, and is specifically represented by the crankshaft axial torque (N · m) corresponding to the engine speed (rpm).

  The fuel injection amount map, the engine load map, and the torque map are appropriately created based on known engine setting specifications such as performance, characteristics, structure, size, and shape of the diesel engine 1, experimental data, and experience data. It is a thing.

The temperature correction coefficient Kth is a dimensionless unit, and is determined based on the detected temperature (° C.) detected by the intake air temperature sensor 21 or the cooling water temperature sensor 22.
Specifically, the temperature correction coefficient Kth is determined based on a temperature correction map based on an appropriately selected cooling water temperature or a temperature correction map based on the intake air temperature shown in FIGS. 4 (a) and 4 (b).
The temperature correction map based on the cooling water temperature is a map showing the relationship between the cooling water temperature thw (° C.) and the temperature correction coefficient Kth, and the temperature correction map based on the intake air temperature is the relationship between the intake air temperature tha (° C.) and the temperature correction coefficient Kth. It is a map which shows a relationship. These maps, as with the other maps, were appropriately created based on known engine setting specifications such as the performance, characteristics, structure, size, and shape of the diesel engine 1, experimental data, and experience data. It is stored in advance in the ROM of the ECU 3 and is read and processed as appropriate.

For example, as shown in FIG. 4A, the temperature correction map based on the cooling water temperature is not subject to temperature correction when the cooling water temperature thw is in the range of 0 ° C. to 20 ° C. It is done. In the range of 20 ° C. and 80 ° C. or less, the temperature correction coefficient Kth is 1, the temperature correction coefficient Kth is 1.05 when the cooling water temperature thw is 90 ° C., and the temperature correction coefficient is 100 ° C. The coefficient Kth is 1.07. The cooling water temperature thw and the temperature correction coefficient Kth have a proportional relationship although not shown, and are represented by continuous curves, and are temperatures other than the cooling water temperature thw shown in FIG. 4A, for example, 20.5 ° C., 85 ° C. The temperature correction coefficient Kth can be determined even at a cooling water temperature thw such as 91 ° C.
Specifically, the temperature correction coefficient Kth corresponding to the detected temperature (° C.) detected by the cooling water temperature sensor 22 is determined from the temperature correction map based on the cooling water temperature.

For example, as shown in FIG. 4B, the temperature correction map based on the intake air temperature is not subject to temperature correction when the intake air temperature tha is in the range of 0 ° C. to less than 20 ° C., and efficient processing of temperature correction is performed. Figured. When the intake air temperature tha is 20 ° C., the temperature correction coefficient Kth is 1, and when the intake air temperature is 40 ° C., the temperature correction coefficient Kth is 1.03, and when it is 80 ° C., the temperature correction coefficient Kth is 1 .05. As in the case of the cooling water temperature thw, the intake air temperature tha and the temperature correction coefficient Kth have a proportional relationship and are represented by continuous curves, and are temperatures other than the intake air temperature tha shown in FIG. The temperature correction coefficient Kth can be determined even when the intake air temperature tha is 5 ° C, 60 ° C, 70.5 ° C, or the like.
Specifically, the temperature correction coefficient Kth corresponding to the detected temperature (° C.) detected by the intake air temperature sensor 21 based on the temperature correction map based on the intake air temperature is determined by the estimated PM emission amount calculation means of the ECU 3.

  The intake air amount correction coefficient Keq is a dimensionless unit, and is set in advance in the diesel engine 1 and is the optimum target intake air amount (g / rev) to be sucked into the cylinder 32 of the engine body 4, that is, the target intake air. The ratio between the air amount (g / rev) and the detected intake air amount (g / rev) detected by the air flow meter 23, that is, the actual intake air amount (g / rev) flowing through the intake passage of the intake pipe 6 It is determined based on the qn ratio representing Specifically, the qn ratio is calculated by the estimated PM emission amount calculation means of the ECU 3 based on the following equation. In this case, since the actual intake air amount (g / rev) is smaller than the target intake air amount (g / rev), the qn ratio is a value smaller than 1.

この吸入空気量補正係数Ｋｅｑは、図５に示すように、ｑｎ比と吸入空気量補正係数Ｋｅｑとの関係を表す曲線で示される吸入空気量補正マップに基づいて決定される。

As shown in FIG. 5, the intake air amount correction coefficient Keq is determined based on an intake air amount correction map indicated by a curve representing the relationship between the qn ratio and the intake air amount correction coefficient Keq.

  The ash accumulation amount correction coefficient Kash is composed of dimensionless units, and the ash accumulation amount obtained from the engine oil supply amount map showing the relationship between the engine oil supply amount (g) and the ash accumulation amount (g) shown in FIG. It is determined based on the amount (g) and the ash deposition amount correction map representing the relationship between the ash deposition amount (g) and the ash deposition amount correction coefficient Kash shown in FIG.

  This engine oil supply amount map is created based on the proportional relationship between the engine oil supply amount (g) and the ash accumulation amount (g), and the performance of the diesel engine 1 is the same as other maps. , Which are appropriately created based on known engine setting specifications such as characteristics, structure, size and shape, experimental data, experience values, etc., and are stored in advance in the ROM of the ECU 3 and appropriately read out. It is processed.

  In the ash accumulation amount correction map, for example, as shown in FIG. 7, when the ash accumulation amount (g) is 0 g, the ash accumulation amount correction coefficient Kash is 1, and when it is 10 g, it is 1.01. , 20 g, it is 1.05, when it is in the range of more than 20 g and less than 100 g, it is 1.07, and when it is 100 g, it is 1.1.

The ash deposition amount and the ash deposition amount correction coefficient Kash have a proportional relationship and are represented by a continuous curve, and the deposition amount (g) other than the ash deposition amount shown in FIG. 7, for example, 5 g, 5.5 g, and 15 g. The ash accumulation amount correction coefficient Kash can be determined even when the ash accumulation amount is 20.5 g or 20.5 g.
Specifically, the ash accumulation amount correction coefficient Kash corresponding to the ash accumulation amount (g) calculated by the ash accumulation amount calculation means of the ECU 3 is determined by the estimated PM emission amount calculation means of the ECU 3.

  Specifically, the PM calculation reference amount storage means of the ECU 3 is composed of the ROM of the ECU 3 and is configured to store a preset PM calculation reference amount, and the PM calculation reference amount is read out as needed.

The engine oil supply amount calculation means of the ECU 3 is configured to calculate the supply amount (g) of the engine oil supplied to the engine body 4, and the calculated engine oil supply amount (g) is directly transmitted to the ECU 3 as appropriate. It is used or stored in a memory such as a RAM of the ECU 3.
Specifically, the engine oil supply amount represents a reduction amount (g) of engine oil stored in the engine body 4 and circulating in the engine body 4, and an oil pan (not shown) of the engine body 4 is shown. The oil level in the oil pan before the engine is started is measured by a known oil level sensor that detects the level of engine oil stored in the engine. The oil level sensor measures the oil level height (mm) in the oil pan before and after a predetermined period or a predetermined traveling condition such as a traveling distance, and the difference between these oil level heights ( mm) and the volume of the oil pan (mm ³ ), so that the engine oil decrease amount is detected.

The engine oil supply amount may be calculated by a method other than the method of detecting the decrease amount of the engine oil by the oil level sensor.
For example, the engine oil reduction amount (g) is calculated by the engine oil supply amount calculation means of the ECU 3 based on the known ASH component (wt%) in the engine oil and the traveling conditions such as the traveling distance (Km). May be estimated. The estimated engine oil reduction amount (g) in this case is appropriately created based on known engine setting specifications such as the performance, characteristics, structure, size, and shape of the diesel engine 1, experimental data, and data such as experience values. The estimated engine oil reduction amount calculation formula is used, and this calculation formula is stored in advance in the ROM of the ECU 3 and is read and processed as appropriate.

  The ash accumulation amount calculation means of the ECU 3 calculates the ash accumulation amount (g) based on the engine oil supply amount (g) calculated by the engine oil supply amount calculation means of the ECU 3 and the engine oil supply amount map shown in FIG. It is configured as follows.

  The engine body 4 includes an engine block 31, a cylinder 32 formed in the engine block 31, an intake device 33, an exhaust device 34, an injector 35, a common rail 36, and an exhaust that injects fuel into the exhaust device 34. The injector 37 and the cooling device 38 are included.

  The engine block 31 is made of, for example, a lightweight aluminum alloy, and includes a cylinder block 31b having a cylinder 32 and a cylinder head (not shown) that supports the injector 35 and the common rail 36. Is attached.

  The cylinder 32 includes four cylinders 32a, 32b, 32c, and 32d. The cylinders 32a to 32d are connected to an intake device 33 via an intake port (not shown), respectively, and an exhaust port (not shown). The exhaust device 34 is connected via

The intake device 33 has an intake passage and has branch portions 33a, 33b, 33c, and 33d that are branched into four at one end. The intake device 33 is connected to the intake pipe 6 at the other end, and is connected to each intake port of the engine body 4 at each end of the branch portions 33a to 33d.
In the intake device 33, air supplied from the intake pipe 6 is supplied from the branch portions 33a to 33d to the cylinders 32a to 32d via the intake ports.

  The exhaust device 34 has branch portions 34a, 34b, 34c, 34d branched into four at one end, and one end of each of the branch portions 34a-34d is connected to each exhaust port of the engine body 4, and the other end The branch portions 34a to 34d are gathered and have a collecting pipe 34e connected to the turbocharger 14. The EGR device 12 is connected to the collecting pipe 34e, and a part of the exhaust gas discharged from the cylinders 32a to 32d flows into the EGR device 12.

The injector 35 includes four injectors 35a, 35b, 35c, and 35d, each having a fuel injection nozzle and provided in each of the cylinders 32a to 32d, and injecting fuel into the cylinders 32a to 32d from the fuel injection nozzle. To make it foggy. This injection is performed according to a command from the ECU 3, and a plurality of injections are performed according to the operating state of the diesel engine 1, such as pilot injection, pre-injection, main injection, and post-injection. Is controlled.
The common rail 36 has a pressure accumulating portion (not shown) that accumulates high-pressure fuel supplied from the fuel supply device 5 and is connected to the injectors 35a to 35d so as to distribute high-pressure fuel to the injectors 35a to 35d. Yes.

  Similarly to the injector 35, the exhaust injector 37 has a fuel injection nozzle and is provided in the collecting pipe 34e. The fuel is injected into the exhaust passage of the collecting pipe 34e to add the fuel to the exhaust gas. It has become. By such fuel injection into the exhaust gas, the exhaust gas aftertreatment device 13 is heated to increase the processing efficiency, and oxidation of deposits such as PM and ash deposited on the exhaust gas aftertreatment device 13 is oxidized. It helps to prevent clogging.

  As shown in FIG. 1, the cooling device 38 includes a radiator 38 r that cools the cooling water that has become hot due to cooling of the engine block 31 with low-temperature outside air, and the cooled cooling water from the radiator 38 r to the engine block 31. An upper pipe 38u that flows into the interior, a lower pipe 38l that flows cooling water from the engine block 31 into the radiator 38r, and a water jacket (not shown) provided in the engine block 31 so that the cooling water flows in the engine block 31. It is configured to include.

  The cooling device 38 further includes a water pump 38p, a bypass pipe 38b interposed between the upper pipe 38u and the lower pipe 38l, and a thermostat 38t provided at a branch portion of the bypass pipe 38b and the upper pipe 38u. It is configured to include.

  The cooling water in the cooling device 38 is air-cooled in the radiator 38r, flows into the water jacket in the engine block 31 from the upper pipe 38u, flows through the cooling water passage including the water jacket in the engine block 31, and then flows into the lower pipe 38l. To the radiator 38r. A cooling water temperature sensor 22 is provided in the vicinity of the water jacket so as to detect the temperature of the cooling water flowing through the water jacket.

  The fuel supply device 5 includes a fuel tank and a fuel pump (not shown), and fuel supply pipes 5a and 5b. The fuel in the fuel tank is made high by the fuel pump and is supplied to the common rail 36 and the exhaust injector 37. It comes to supply.

  The intake pipe 6 is a pipe that introduces fresh air sucked from an intake port (not shown) into the intake device 33 and has an intake passage. The intake pipe 6 is connected to the turbocharger 14 so that fresh air in the intake passage passes through the turbocharger 14. It is introduced into the intake device 33 via. Further, fresh air in the intake passage is purified by an air cleaner 7 provided in the intake pipe 6 and further cooled by an intercooler 8 provided in the intake pipe 6 to increase the density.

  The throttle valve 9 is composed of, for example, a throttle valve such as a butterfly valve, and adjusts the amount of fresh air that has passed through the intercooler 8 into the engine in response to a command from the ECU 3.

  The exhaust pipe 11 is a pipe that discharges exhaust gas discharged from the collecting pipe 34e of the exhaust device 34 to the atmosphere, has an exhaust passage, and one end is connected to the collecting pipe 34e. The exhaust pipe 11 is provided with an exhaust gas aftertreatment device 13 so that harmful substances in the exhaust gas are removed. The exhaust pipe 11 is provided with a silencer such as a muffler (not shown) on the downstream side of the exhaust gas aftertreatment device 13.

The EGR device 12 includes an EGR pipe 41, an EGR valve 42, and an EGR cooler 43, and recirculates exhaust gas in the exhaust passage of the exhaust device 34 into the intake passage of the intake device 33. It has become.
The EGR pipe 41 has an EGR passage, and an EGR valve 42 is provided on the intake device 33 side of the EGR pipe 41, and an EGR cooler 43 is provided on the exhaust device 34 side of the EGR pipe 41. .
The opening degree of the EGR valve 42 is controlled by the ECU 3, the amount of exhaust gas recirculated into the intake passage is adjusted, and a predetermined external EGR rate is obtained. Further, the EGR cooler 43 reduces the temperature of the exhaust gas to be recirculated and increases its density.

  The exhaust gas aftertreatment device 13 is a so-called catalytic converter including a housing 51, an oxidation catalyst 52, a DPF 53 as a PM collection filter, and a catalyst holding seal 54 that holds the oxidation catalyst 52 and the DPF 53 in the housing 51. It is configured. In the exhaust gas aftertreatment device 13, the exhaust gas flowing in from the upstream exhaust pipe 11 is purified and discharged to the downstream exhaust pipe 11.

  As shown in FIG. 3, the housing 51 has a cylindrical tube portion 51e, a connection portion 51j having a flange 51f formed in a substantially conical shape and connected to the exhaust pipe 11 on the upstream side, and a downstream formed in a substantially conical shape. And a connecting portion 51k having a flange 51f connected to the exhaust pipe 11 on the side, and an oxidation catalyst 52 and a DPF 53 are accommodated in the inside via a catalyst holding seal 54. Further, the exhaust temperature sensor 25 is mounted on the housing 51 at two locations on the upstream side and the downstream side of the oxidation catalyst 52, and the upstream pressure detection unit 24 j and the downstream pressure detection unit 24 k of the differential pressure sensor 24.

The oxidation catalyst 52 is made of a catalytic metal such as platinum or palladium that has an oxidation activity with respect to various gases, and oxidizes harmful substances such as HC in the exhaust gas to produce CO ₂ (carbon dioxide) and H ₂ O (water vapor). ) To be disassembled.

  The DPF 53 is made of a catalyst carrier made of, for example, a ceramic such as cordierite or a metal such as alumina, and is composed of a honeycomb having a plurality of spaces penetrating in the axial direction so as to allow exhaust gas to pass therethrough. belongs to. The particulate matter such as PM and ash in the exhaust gas that passes through the honeycomb is collected, and the inner surface of the honeycomb is reduced by an active metal that purifies exhaust gas components such as platinum, palladium, and rhodium. A catalyst is supported, and the chemical reaction of the exhaust gas flowing through the honeycomb is promoted.

  Examples of the reduction catalyst include a DPNR catalyst (Diesel Particulate-NOx Reduction catalyst), and the PM in the exhaust gas is collected by the DPNR catalyst and is simultaneously purified with NOx in the exhaust gas. Yes. During these purifications, PM is oxidized, CO (carbon monoxide) and HC (hydrocarbon) are also oxidized, and NOx is reduced.

  The PM accumulated in the DPF 53 increases with time, the DPF becomes clogged, the exhaust resistance increases, the fuel consumption rate (g / KWh) deteriorates, and the catalyst and DPF may be damaged. Therefore, the PF regeneration process is periodically performed under the control of the ECU 3, and the accumulated PM is removed.

  The turbocharger 14 supports the exhaust turbine portion 14t, the compressor portion 14c, the shaft 14s connecting the exhaust turbine portion 14t and the compressor portion 14c, the exhaust turbine portion 14t and the compressor portion 14c, and rotatably supports the shaft 14s. And a bearing housing portion (not shown).

  The exhaust pipe 11 is connected to the exhaust turbine section 14t, and the exhaust gas flows into the exhaust turbine section 14t and is discharged to the exhaust pipe 11 connected to the downstream side. The intake pipe 6 is connected to the compressor section 14c, and the intake air purified through the air cleaner 7 flows into the compressor section 14c and is supercharged to the intake pipe 6 connected to the downstream side of the compressor section 14c. The intake air is discharged.

  Next, a process for calculating the estimated PM emission amount in the PM emission amount estimation device 2 according to the first embodiment will be described.

  The flowchart shown in FIG. 8 shows the execution contents of a program for calculating the estimated PM emission amount stored in the ROM of the ECU 3, and the program for calculating the estimated PM emission amount is an engine start determination. It comprises a single program or a plurality of programs for executing the functional contents of the means, the estimated PM discharge amount calculation means, the PM calculation reference amount storage means, the engine oil supply amount calculation means, and the ash accumulation amount calculation means. The program for calculating the estimated PM emission amount is executed by the CPU of the ECU 3.

  As shown in FIG. 9, when the program for calculating the estimated PM emission amount is executed, the ECU 3 determines whether the starter switch for operating the starter motor of the diesel engine 1 has been turned on by the engine start determination unit. Start monitoring. When it is detected that the starter switch is turned on, it is determined that the diesel engine 1 has been started. When it is not detected, the ECU 3 determines that the diesel engine 1 has been started at predetermined time intervals. Until the starter switch is turned on or off, the monitoring is continued (step S1).

Next, the ECU 3 determines whether or not the PM regeneration process has been completed (step S2).
Specifically, in the PM regeneration process, when a certain amount of accumulated PM is collected in the DPF 53, the PM accumulated in the DPF is heated to, for example, about 600 ° C., and the PM is subjected to an oxidation reaction. It is caused to oxidize and remove, and control of the fuel injection amount by post injection of the injector 35 shown in FIG. 1 by the ECU 3 or exhaust gas in the collecting pipe 34e of the exhaust device 34 by the exhaust injector 37 shown in FIG. This is performed by controlling the amount of fuel injected into the ECU 3. The optimum timing of fuel injection in the post injection control by the ECU 3 and the fuel injection control into the exhaust gas is, for example, the estimated PM accumulation amount (g) in the DPF 53 obtained by the ECU 3 is set to a preset PM regeneration processing reference accumulation. Judgment is made based on whether the amount (g) has been reached.

  Whether or not this PM regeneration processing has ended is determined whether or not a preset set time has elapsed since the start of post injection control or fuel injection control into the exhaust gas by the ECU 3, or a differential pressure sensor It is judged whether or not the differential pressure (kPa) detected by 24 has become equal to or lower than a preset differential pressure (kPa).

  When the set time is used as a reference, the set time is the catalyst bed temperature (° C.) estimated from the temperature of the exhaust gas detected by the exhaust temperature sensor 25 provided in the exhaust gas aftertreatment device 13, or It is predetermined based on the flow rate (g / min) of the exhaust gas flowing through the exhaust gas aftertreatment device 13. For example, when the catalyst bed temperature (° C.) is T ° C. and t seconds elapses, the PM removal amount (g) of the target PM is calculated by a known calculation formula that PM accumulated in the DPF 53 burns m (g). It can be estimated, and it can be determined whether the PM regeneration process has ended by counting whether the set time has elapsed.

  When determining whether or not the PM regeneration process has ended based on the set time, when the ECU 3 recognizes that this set time has elapsed, it is determined that the PM regeneration process has ended, and the set differential pressure is used as a reference. In the case where it is determined whether or not the PM regeneration process is finished, the PM regeneration process is finished when the ECU 3 recognizes that the differential pressure detected by the differential pressure sensor 24 is equal to or lower than the set differential pressure. It is judged that

  If it is determined in step S2 that the PM regeneration process has ended, the ECU 3 needs to correct the ash accumulation amount, that is, the PM emission amount estimation device 2 according to the first embodiment needs to calculate the estimated PM emission amount. Whether or not (step S3).

  Specifically, as shown in FIG. 9, this determination is based on the difference when the differential pressure (kPa) after the PM regeneration process detected by the differential pressure sensor 24 is preset and the travel distance of the vehicle is close to zero. The initial value (kPa) of the differential pressure detected by the pressure sensor 24 and the differential pressure value (kPa) that requires correction of the ash deposition amount, that is, the differential pressure value (kPa) that requires calculation of the estimated PM discharge amount. It is performed based on whether it is in the range. The differential pressure value (kPa) that requires correction of the ash accumulation amount is the data of known engine setting parameters such as the performance, characteristics, structure, size, and shape of the diesel engine 1, experimental data, experience values, and the like. Based on this, it is appropriately created, stored in advance in the ROM of the ECU 3, and read and processed as appropriate.

  Specifically, as shown in FIG. 9, the differential pressures P1 and P2 after the end of the PM regeneration process are within the range of the differential pressure value that requires correction of the initial value of the differential pressure and the ash deposition amount. It is determined that the correction of the ash deposition amount is not necessary, and the differential pressure P3 exceeds the differential pressure value that requires the correction of the ash deposition amount. Therefore, it is determined that the correction of the ash deposition amount is necessary.

  If it is determined in step S3 that the ash accumulation amount needs to be corrected, the cooling water temperature sensor 22 detects the temperature (° C.) of the cooling water flowing through the engine block 31 of the engine body 4, and the detected temperature (° C.) is Input to the ECU 3 (step S4).

Next, the ECU 3 determines a temperature correction coefficient Kth based on the detected temperature (° C.) of the cooling water and the temperature correction map based on the cooling water temperature shown in FIG. 4A (step S5).
In step S4, the temperature (° C.) of the intake air flowing through the intake pipe 6 may be detected by the intake temperature sensor 21, and the detected temperature (° C.) may be input to the ECU 3. In this case, the ECU 3 The temperature correction coefficient Kth can be determined based on the detected temperature (° C.) of the intake air and the temperature correction map based on the intake air temperature shown in FIG.

  Next, the ECU 3 detects the intake air amount (g / rev) flowing through the intake pipe 6 by the air flow meter 23 and inputs the detected intake air amount (g / rev) to the ECU 3 (step S6).

  Next, the ECU 3 determines the intake air amount correction coefficient Keq based on the detected intake air amount (g / rev), the qn ratio calculation formula shown in FIG. 5, and the intake air amount correction map (step S7).

  Next, the ECU 3 calculates the engine oil supply amount (g) supplied into the engine body 4 by the engine oil supply amount calculation means (step S8).

  Next, the ECU 3 determines the ash accumulation accumulated in the DPF 53 by the ash accumulation amount calculating means based on the engine oil supply amount (g) calculated by the engine oil supply amount calculating means and the engine oil supply amount map shown in FIG. The amount (g) is calculated (step S9).

  Next, the ECU 3 determines an ash accumulation amount correction coefficient Kash based on the ash accumulation amount (g) calculated by the ash accumulation amount calculation means and the ash accumulation amount correction map shown in FIG. 7 (step S10).

  Next, the ECU 3 uses the estimated PM discharge amount calculating means to determine the PM calculation reference amount (g) stored in the PM calculation reference amount storage means, the temperature correction coefficient Kth determined in step S5, and the intake air determined in step S7. The amount correction coefficient Keq and the ash accumulation amount correction coefficient Kash determined in step S10 are respectively substituted into the following expressions, PMe = PMb × Kth × Keq × Kash, and the estimated PM emission amount PMe (g) is calculated ( Step S11).

  Next, the ECU 3 receives a notification of the calculated estimated PM emission amount PMe (g) (step S12).

  Next, the ECU 3 determines whether or not the diesel engine 1 has been stopped (step S13). If it is determined that the diesel engine 1 has stopped, the ECU 3 returns to step S1 and determines whether or not the diesel engine 1 has started. Monitoring is performed by the ECU 3. If it is determined that the diesel engine 1 is not stopped, the process returns to step S2 to continue calculating the estimated PM emission amount.

  Since the PM emission amount estimation device 2 according to the first embodiment is configured as described above, the following effects are obtained.

  That is, the PM discharge amount estimation device 2 includes an intake air temperature sensor 21, an air flow meter 23, a DPF 53, an estimated PM discharge amount calculation unit of the ECU 3, an engine oil supply amount calculation unit, and a PM calculation reference amount storage unit, and a detected temperature, a detection The PM discharge amount is estimated based on the intake air amount and the PM calculation reference amount. The PM emission amount estimation device 2 further includes an ash accumulation amount calculation unit of the ECU 3, and the ash accumulation amount calculation unit calculates the ash accumulation amount based on the engine oil supply amount calculated by the engine oil supply amount calculation unit. Then, the estimated PM emission amount calculation means of the ECU 3 sets the PM calculation reference amount as PMb, the temperature correction coefficient as Kth, the intake air amount correction coefficient as Keq, the ash accumulation amount correction coefficient as Kash, and the estimated PM emission amount as Assuming PMe, the estimated PM emission amount PMe discharged from the engine is calculated based on PMe = PMb × Kth × Keq × Kash.

  As a result, it is possible to obtain a highly accurate estimated PM emission amount that approximates the actual PM emission amount discharged from the engine, and it is possible to prevent ash and PM over-deposition.

  In the conventional PM emission amount estimation device, the PM calculation reference amount is multiplied by a temperature correction coefficient for correcting the PM calculation reference amount with the detected temperature and an intake air amount correction coefficient for correcting the PM calculation reference amount with the intake air amount. As a result, the estimated PM accumulation amount is calculated. In the PM emission amount estimation device 2 according to the first embodiment, the PM calculation reference amount is further multiplied by the ash accumulation amount correction coefficient Kash. The PM calculation reference amount is corrected.

  As a result, as shown in FIG. 10, the conventional estimated PM deposition amount remained linearly substantially constant despite the increase in the ash deposition amount, whereas the PM according to the first embodiment. In the discharge amount estimation device 2, since the correction by the ash accumulation amount correction coefficient Kash is performed, there is an effect that the obtained estimated PM accumulation amount becomes a highly accurate value that approximates the actual actual discharge amount. can get. That is, the difference between the conventional estimated PM accumulation amount and the actual actual emission amount is remarkably reduced, and the difference between the estimated PM accumulation amount and the actual actual emission amount is improved.

  Further, as shown in FIG. 11 (a), the conventional PM regeneration interval, that is, the interval of the PM regeneration processing is based on the threshold (g) of the PM deposition amount deposited on the DPF. The estimated PM accumulation amount estimated by the apparatus and the actual actual emission amount are different from each other, and the traveling distance of the vehicle is about every 100 km. At the start of the PM regeneration process, the actual amount of PM deposited in the DPF has exceeded the threshold value as shown by the alternate long and short dash line, so the risk of DPF erosion has increased. In addition, an increase in the actual amount of PM deposited in the DPF causes clogging of the DPF and increases the exhaust resistance, which may cause a deterioration in the fuel consumption rate (g / KWh).

  With respect to such a conventional PM regeneration interval, in the PM emission amount estimation device 2 of the first embodiment, the difference between the estimated PM accumulation amount and the actual actual emission amount is remarkably small. As shown in (b), the vehicle travel distance reaches the threshold (g) of the PM accumulation amount accumulated in the DPF at about 50 Km, which is a fine PM regeneration interval. As a result, the risk of DPF erosion can be reduced, clogging of the DPF can be prevented, and the increase in exhaust resistance can be suppressed, thereby suppressing deterioration in the fuel consumption rate (g / KWh). The effect of being able to be obtained.

The PM emission amount estimation device 2 according to the first embodiment has been described as applied to the diesel engine 1 including the turbocharger 14.
However, the PM emission amount estimation device according to the present invention may be applied to an engine that does not include a turbocharger. In this case, the PM calculation reference amount (g), the temperature correction coefficient Kth, the intake air amount correction coefficient Keq, and the ash accumulation amount correction coefficient Kash, which are substituted into the following expressions, PMe = PMb × Kth × Keq × Kash, respectively. These values are appropriately corrected and determined as applied to an engine not equipped with a turbocharger.

Further, the PM emission amount estimation device 2 according to the first embodiment has been described for the case where the intake air temperature sensor 21 is disposed between the air cleaner 7 and the turbocharger 14.
However, in the PM emission amount estimation device according to the present invention, the intake air temperature sensor may be disposed in a portion other than between the air cleaner and the turbocharger. For example, it may be arranged between the intercooler and the intake device. Also in this case, the PM calculation reference amount (g), the temperature correction coefficient Kth, the intake air amount correction coefficient Keq, and the ash accumulation amount correction coefficient Kash, which are substituted into the following expressions, PMe = PMb × Kth × Keq × Kash, respectively. Each of these values is determined by appropriately correcting and determining that the intake air temperature sensor is disposed between the intercooler and the intake device.

(Second Embodiment)
First, the configuration of the PM emission amount estimation apparatus 102 according to the second embodiment will be described.
The PM emission amount estimation apparatus 102 according to the second embodiment constitutes a part of the diesel engine 101 mounted on the vehicle, as in the first embodiment.

  Specifically, as shown in FIG. 1, the diesel engine 101 includes a PM emission amount estimation device 102 and an ECU 103 that includes a part of the PM emission amount estimation device 102 and controls the diesel engine 101. The other components are configured in the same manner as in the first embodiment.

  Note that the PM emission amount estimation device 102 according to the second embodiment is different in that the ECU 3 of the first embodiment is configured as the ECU 103, but other components are related to the first embodiment. The PM emission amount estimation device 2 is configured in the same manner. Therefore, the same configuration will be described using the same reference numerals as those of the first embodiment shown in FIGS. 1 to 11, and only differences will be described in detail.

  The ECU 103 is configured in the same manner as the ECU 3 of the first embodiment, and the ash accumulation amount calculation unit calculates the ash accumulation amount based on the engine oil supply amount calculated by the engine oil supply amount calculation unit. Instead, the only difference is that the ash accumulation amount calculating means calculates the ash accumulation amount based on the differential pressure detected by the differential pressure sensor 24.

  Specifically, in the estimated PM emission amount calculating means of the ECU 103, as in the estimated PM emission amount calculating means of the ECU 3 of the first embodiment, the PM calculation reference amount (g) is PMb, and the temperature correction coefficient is Kth. Assuming that the intake air amount correction coefficient for correcting the PM calculation reference amount PMb (g) based on the detected intake air amount (g / rev) detected by the air flow meter 23 is Keq, the ash accumulation amount calculated by the ash accumulation amount calculating means Assuming that the ash accumulation amount correction coefficient for correcting the PM calculation reference amount PMb (g) from (g) is Kash, and the estimated PM emission amount (g) discharged from the diesel engine 1 is PMe, the following formula, PMe = PMb × Based on Kth × Keq × Kash, the estimated PM emission amount (g) is calculated.

  As in the first embodiment, the ash accumulation amount correction coefficient Kash in the ECU 103 of the second embodiment is composed of dimensionless units, and is a difference between the differential pressure value (kPa) and the ash accumulation amount (g) shown in FIG. The ash accumulation amount (g) obtained from the differential pressure value map representing the relationship, and the ash accumulation amount correction map representing the relationship between the ash accumulation amount (g) and the ash accumulation amount correction coefficient Kash shown in FIG. To be determined.

  This differential pressure value map is created based on the fact that the detected differential pressure (kPa) detected by the differential pressure sensor 24 and the ash deposition amount (g) are in a proportional relationship. Like the other maps, It is appropriately created based on known engine setting specifications such as performance, characteristics, structure, size and shape of the diesel engine 101, experimental data, experience values, etc., and is stored in the ROM of the ECU 103 in advance. It is read and processed as appropriate.

  Next, a process for calculating an estimated PM emission amount in the PM emission amount estimation apparatus 102 according to the second embodiment will be described.

  The flowchart shown in FIG. 13 shows the execution contents of the program for calculating the estimated PM emission amount stored in the ROM of the ECU 103, as in the first embodiment, and the calculation of this estimated PM emission amount. The processing program includes a single program or a plurality of programs that execute the function contents of the engine start determination unit, the estimated PM emission amount calculation unit, the PM calculation reference amount storage unit, and the ash accumulation amount calculation unit. The program for calculating the estimated PM emission amount is executed by the CPU of the ECU 103.

  As shown in FIG. 13, in the calculation process of the estimated PM emission amount in the PM emission amount estimation apparatus 102 according to the second embodiment, each step from step S101 to step S107 is performed according to the PM according to the first embodiment. It is executed in the same manner as each step from step S1 to step S7 in the discharge amount estimation device 2.

  Next, the ECU 103 stores the detected differential pressure (kPa) detected by the differential pressure sensor 24, that is, the differential pressure value (kPa), for example, in a memory such as a RAM (step S108).

  Next, the ECU 103 calculates the ash accumulation amount (g) accumulated in the DPF 53 based on the differential pressure value (kPa) detected by the differential pressure sensor 24 and the differential pressure value map shown in FIG. 12 (step S109). ).

  Next, the ECU 103 executes the steps from step S110 to step S113 in the same manner as the steps from step S10 to step S13 in the PM emission amount estimation device 2 according to the first embodiment.

  Since the PM emission amount estimation apparatus 102 according to the second embodiment is configured as described above, the following effects are obtained.

  That is, the PM discharge amount estimation device 102 includes an intake temperature sensor 21, an air flow meter 23, a DPF 53, an estimated PM discharge amount calculation means and a PM calculation reference amount storage means of the ECU 103, and includes a detected temperature, a detected intake air amount, and a PM calculation reference. The PM emission amount is estimated based on the amount. The PM discharge amount estimation device 102 includes a differential pressure sensor 24 and an ash accumulation amount calculation unit of the ECU 103. The ash accumulation amount calculation unit calculates an ash accumulation amount based on the detected differential pressure, and the ECU 103 estimates the PM discharge amount. When the amount calculating means sets PMb as the PM calculation reference amount, Kth as the temperature correction coefficient, Keq as the intake air amount correction coefficient, Kash as the ash accumulation amount correction coefficient, and PMe as the estimated PM discharge amount, PMe = PMb The estimated PM emission amount PMe discharged from the engine is calculated based on × Kth × Keq × Kash.

  As a result, as in the first embodiment, it is possible to obtain a highly accurate estimated PM emission amount that approximates the actual PM emission amount discharged from the engine, and ash and PM overdeposition can be prevented. Can be prevented.

  Also in the PM emission amount estimation device 102 according to the second embodiment, since the correction by the ash accumulation amount correction coefficient Kash is performed by the differential pressure value, the obtained estimated PM accumulation amount is almost the actual actual emission amount. An effect of obtaining an approximate and highly accurate value is obtained. That is, the difference between the conventional estimated PM accumulation amount and the actual actual emission amount is remarkably reduced, and the difference between the estimated PM accumulation amount and the actual actual emission amount is improved.

  Further, the PM regeneration interval is also a fine PM regeneration interval because the difference between the estimated PM accumulation amount and the actual actual discharge amount is remarkably small as in the PM regeneration interval in the first embodiment. As a result, the risk of DPF erosion can be reduced, clogging of the DPF can be prevented, and the increase in exhaust resistance can be suppressed, thereby suppressing deterioration in the fuel consumption rate (g / KWh). The effect of being able to be obtained.

  As described above, in the PM emission amount estimation device according to the present invention, highly accurate estimated PM emission approximated to the actual PM emission amount discharged from the engine so as to prevent ash and PM from being excessively accumulated. This has the effect of providing a PM emission amount estimation device that can provide a large amount, and is useful for general engine PM emission amount estimation devices and PM accumulation amount estimation devices.

DESCRIPTION OF SYMBOLS 1,101 Diesel engine 2,102 PM emission amount estimation apparatus 3,103 Electronic control unit (ECU)
13 Exhaust gas aftertreatment device 21 Intake air temperature sensor 22 Cooling water temperature sensor 23 Air flow meter 24 Differential pressure sensor 25 Exhaust temperature sensor 26 Crank position sensor 53 PM collection filter (DPF)

Claims (1)

An intake air temperature sensor for detecting the temperature of intake air sucked into the engine, a cooling water temperature sensor for detecting the temperature of cooling water for cooling the engine, an air flow meter for detecting the amount of intake air sucked into the engine, An estimated PM emission amount calculating means for calculating an estimated emission amount of PM composed of particulate matter discharged from the engine, and a PM calculation criterion as a calculation reference for the estimated PM emission amount calculated by the estimated PM emission amount calculating means A PM calculation reference amount storage means for storing the amount, a detected temperature detected by at least one of the intake air temperature sensor and the cooling water temperature sensor, and a detected intake air amount detected by the air flow meter, In the PM emission amount estimation device for estimating the PM emission amount discharged from the engine based on the PM calculation reference amount,
A pressure of exhaust gas in the exhaust passage upstream of a PM collection filter disposed in the exhaust passage of the engine and collecting PM, and a pressure of exhaust gas in the exhaust passage downstream of the PM collection filter; A differential pressure sensor for detecting the difference between
Engine oil supply amount calculating means for calculating a supply amount of engine oil supplied to the engine;
Ash accumulation amount calculating means for calculating an accumulation amount of ash composed of incombustible components discharged from the engine,
The PM calculation reference amount includes a reference amount obtained from a map created based on at least one of the injection amount of fuel injected into the engine, the engine load, and the torque output from the engine. ,
The ash accumulation amount calculating means calculates the ash accumulation amount based on at least one of the differential pressure detected by the differential pressure sensor and the engine oil supply amount calculated by the engine oil supply amount calculation means;
The estimated PM discharge amount calculation means sets the PM calculation reference amount as PMb, sets a temperature correction coefficient for correcting the PM calculation reference amount PMb by the detected temperature as Kth, and sets the PM calculation reference amount PMb as the detected intake air amount. The intake air amount correction coefficient for correcting the ash accumulation amount is Keq, the ash accumulation amount correction coefficient for correcting the PM calculation reference amount PMb based on the ash accumulation amount calculated by the ash accumulation amount calculating means is Kash, and the engine is discharged from the engine. When the estimated PM emission amount is PMe, the PM emission amount estimation device calculates the estimated PM emission amount based on the following formula: PMe = PMb × Kth × Keq × Kash.

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