JP2010174682A - Intake temperature detector for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To appropriately correct intake temperature detected by an intake temperature sensor without being influenced by an operation state. <P>SOLUTION: An intake temperature detector for an internal combustion engine corrects intake temperature detected by the intake temperature sensor by regulating intake temperature supplied to an intake system while controlling an electric motor according to a change in output of the internal combustion engine so that driving force to be output is matched with required driving force. Thereby, even if the intake temperature sensor has deteriorated responsiveness due to deposit adhesion, the intake temperature detected by the intake temperature sensor is appropriately corrected. Specifically, for compensating insufficient or excessive driving force output from the internal combustion engine by using the electric motor so as to provide the required driving force, the intake temperature detected by the intake temperature sensor is appropriately corrected without being influenced by the operation state. Accordingly, it is possible to appropriately suppress emission deterioration during correction and fuel economy deterioration. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an intake air temperature detection device for an internal combustion engine.

  This type of technique is proposed in Patent Documents 1 and 2. In Patent Document 1, in an internal combustion engine equipped with an intake air control device that controls the intake air temperature according to the load state of the internal combustion engine, correction is performed in anticipation of a response delay of the intake air temperature sensor when switching between introduction of cold air and hot air. It has been proposed to do the processing. Patent Document 2 proposes that an intake air temperature sensor is provided between the intake passage on the downstream side of the I / C and the EGR connection portion, and that the delay of the intake air temperature sensor is corrected according to the EGR introduction amount.

JP 2001-140690 A JP 2000-303895 A

  However, in the technique described in Patent Document 1 described above, the correction process corresponds to a temporary response delay of the intake air temperature sensor when the intake air temperature is switched, and the correction process is performed depending on the operating state. Sometimes it was difficult. For this reason, it has been difficult to appropriately cope with a case where soot or the like adheres to the intake air temperature sensor due to the introduction of EGR or the like and a response delay of the intake air temperature sensor is always expected. The same applies to the technique described in Patent Document 2.

  The present invention has been made to solve the above-described problems, and is an internal combustion engine capable of appropriately correcting the intake air temperature detected by the intake air temperature sensor without being influenced by the operation state. An object of the present invention is to provide an intake air temperature detection device.

  In one aspect of the present invention, an intake air temperature detection device for an internal combustion engine applied to a vehicle having an electric motor capable of at least one of regeneration and power running is provided in an intake passage and detects an intake air temperature. A sensor, intake air temperature control means for controlling the intake air temperature of the internal combustion engine by introducing either cold air from the cold air supply source or hot air from the hot air supply source into the intake passage, and driving force of the vehicle The motor is controlled in accordance with the operating state so that the motor is matched with the required driving force, and the control of the intake air temperature by the intake air temperature control means is executed to compensate for the response delay of the intake air temperature sensor. And an intake air temperature correcting means for correcting the intake air temperature detected by the intake air temperature sensor.

  The above-mentioned intake air temperature detection device for an internal combustion engine is controlled by using an electric motor in accordance with a change in the output of the internal combustion engine so that the output driving force matches the required driving force, and the intake air temperature supplied to the intake system Is adjusted to correct the intake air temperature detected by the intake air temperature sensor. This makes it possible to correct the intake air temperature regardless of the operating state by compensating for the deficiency / excess of the driving force output from the internal combustion engine using the electric motor and matching the required driving force. it can. Moreover, at the time of such correction, the driving force necessary for driving the vehicle can be ensured appropriately, and the excess driving force can appropriately suppress the deterioration of emissions and fuel consumption by regenerating as power energy. Can do.

  In one aspect of the intake air temperature detection device for an internal combustion engine, the intake air temperature control means is an EGR device that recirculates a part of the exhaust gas discharged from the combustion chamber to the intake passage as EGR gas.

  According to this aspect, the intake air temperature can be raised by recirculating the EGR gas warmed by combustion, and the intake air temperature can be lowered by recirculating the EGR gas sufficiently cooled by an EGR cooler or the like. Can do. As a result, emission deterioration during execution of the intake air temperature correction means is suppressed.

The schematic block diagram of the hybrid vehicle in this embodiment is shown. 1 is a schematic configuration diagram of an intake air temperature detection device for an internal combustion engine in the present embodiment. It is a flowchart which shows the intake temperature sensor learning process in 1st Embodiment. It is a flowchart which shows the low pressure EGR valve opening degree learning process in 1st Embodiment. It is a flowchart which shows the intake temperature sensor time constant and gain learning process in 2nd Embodiment.

  Preferred embodiments of the present invention will be described below with reference to the drawings.

[Device configuration]
FIG. 1 is a schematic configuration diagram of a hybrid vehicle in the present embodiment. Note that broken line arrows in the figure indicate signal input / output.

  The hybrid vehicle 100 mainly includes an engine (internal combustion engine) 1, an axle 2, a drive wheel 3, a first motor generator MG1, a second motor generator MG2, a power split mechanism 4, an inverter 5a, 5b, a battery 6, and an ECU (Electronic Control Unit) 70.

  The axle 2 is a part of a power transmission system that transmits the power of the engine 1 and the second motor generator MG2 to the wheels 3. The wheels 3 are wheels of the hybrid vehicle 100, and only the left and right front wheels are particularly shown in FIG. The engine 1 is configured as a diesel engine and functions as a power source that outputs the main driving force of the hybrid vehicle 100. Various controls are performed on the engine 1 by the ECU 70.

  The first motor generator MG1 is configured to function mainly as a generator for charging the battery 6 or a generator for supplying electric power to the second motor generator MG2. Generate electricity. The second motor generator MG2 is mainly configured to function as an electric motor that assists (assists) the output of the engine 1. These motor generators MG1 and MG2 are configured as, for example, synchronous motor generators, and include a rotor having a plurality of permanent magnets on the outer peripheral surface and a stator wound with a three-phase coil that forms a rotating magnetic field.

  Power split device 4 corresponds to a planetary gear (planetary gear mechanism) configured with a sun gear, a ring gear, and the like, and is configured to be able to distribute the output of engine 1 to first motor generator MG1 and axle 2. ing.

  Inverter 5a is a DC / AC converter that controls input / output of electric power between battery 6 and first motor generator MG1, and inverter 5b is an inverter that converts electric power between battery 6 and second motor generator MG2. This is a DC / AC converter that controls input and output. For example, the inverter 5a converts AC power generated by the first motor generator MG1 into DC power and supplies it to the battery 6, and the inverter 5b converts the DC power extracted from the battery 6 into AC power. 2 is supplied to the motor generator MG2.

  The battery 6 is configured to be capable of functioning as a power source for driving the first motor generator MG1 and / or the second motor generator MG2, and the first motor generator MG1 and / or the second motor. It is a storage battery configured to be able to charge power generated by the generator MG2. Hereinafter, when the first motor generator MG1 and the second motor generator MG2 are used without being distinguished from each other, they are simply referred to as “motor generator MG”.

  The ECU 70 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like (not shown), and performs various controls on each component in the hybrid vehicle 100. Although details will be described later, the ECU 70 functions as an intake air temperature correction means in the present invention.

  FIG. 2 is a schematic configuration diagram of the internal combustion engine 81 having the intake air temperature detection device in the present embodiment. The internal combustion engine 81 is applied to the hybrid vehicle 100 shown in FIG. In FIG. 2, solid arrows indicate an example of the flow of intake and exhaust.

  As shown in FIG. 2, the internal combustion engine 81 mainly includes an engine 1, a fuel injection valve 15, an intake air temperature sensor 16, a fuel addition valve 17, an air cleaner 19, an intake passage 20, a throttle valve 22a, 22b, turbocharger 23, intercooler (IC) 24, exhaust passage 25, oxidation catalyst 26, DPF (Diesel Particulate Filter) 27, exhaust throttle valve 29, A / F sensor 30, high pressure EGR A device 50 and a low-pressure EGR device 51 are provided.

  The engine 1 is configured as, for example, an in-line four-cylinder diesel engine, and outputs a driving power source in the hybrid vehicle 100. Each cylinder of the engine 1 is connected to an intake manifold 11 and an exhaust manifold 12. Hereinafter, the intake manifold is simply referred to as “intake manifold”, and the exhaust manifold is simply referred to as “exhaust manifold”. The engine 1 includes a fuel injection valve 15 provided in each cylinder, and a common rail 14 that supplies high-pressure fuel to each fuel injection valve 15, and the fuel is in a high-pressure state on the common rail 14 by a fuel pump (not shown). Supplied in. Further, the exhaust manifold 12 is provided with a fuel addition valve 17 for adding fuel.

  On the intake passage 20 connected to the intake manifold 11, an air cleaner 19 for purifying the intake air, throttle valves 22a and 22b for adjusting the air amount, a compressor 23a of a turbocharger 23 for supercharging the intake air, and the intake air are cooled. And an intercooler 24. The intake manifold 11 is provided with an intake air temperature sensor 16 for detecting the intake air temperature. The intake air temperature sensor 16 supplies the ECU 70 with a detection signal corresponding to the detected intake air temperature.

  On the exhaust passage 25 connected to the exhaust manifold 12, the turbine 23 b of the turbocharger 23 rotated by the energy of the exhaust gas, the oxidation catalyst 26 and the DPF 27 that can purify the exhaust gas, and the exhaust gas flow rate downstream of the DPF 27 An exhaust throttle valve 29 capable of adjusting the A / F and an A / F sensor 30 for detecting A / F (air-fuel ratio) of the exhaust gas are provided. Instead of DPF 27, DNR (Diesel Particulate-NOx Reduction System) having NSR (NOx Storage Reduction) and DPR (Diesel Particulate Active Reduction System) may be used.

  Further, the internal combustion engine 81 includes a high pressure EGR device 50 (HPL (High Pressure Loop) EGR device) that recirculates exhaust gas from the upstream side of the turbine 23b to the downstream side of the compressor 23a, and the compressor 23a from the downstream side of the turbine 23b. A low pressure EGR device 51 (an LPL (Low Pressure Loop) EGR device) that recirculates the exhaust gas is provided upstream. The high pressure EGR device 50 includes a high pressure EGR passage 31 and a high pressure EGR valve 33. The high-pressure EGR passage 31 is a passage that connects the upstream position of the turbine 23b in the exhaust passage 25 and the downstream position from the intercooler 24 in the intake passage 20, and controls the amount of exhaust gas to be recirculated on the passage. A high pressure EGR valve 33 is provided. The high pressure EGR valve 33 is controlled to be opened and closed by a control signal supplied from the ECU 70.

  The low pressure EGR device 51 includes a low pressure EGR passage 35, a low pressure EGR cooler 36, and a low pressure EGR valve 37. The low pressure EGR passage 35 is a passage connecting a downstream position of the DPF 27 on the exhaust passage 25 and an upstream position of the intake passage 20 in the compressor 23a. A low pressure EGR cooler 36 that cools the exhaust gas to be recirculated and a low pressure EGR valve 37 that controls the amount of exhaust gas to be recirculated are provided on the low pressure EGR passage 35. The low pressure EGR valve 37 is controlled to be opened and closed by a control signal supplied from the ECU 70.

  When the EGR gas is recirculated by both the high pressure EGR device 50 and the low pressure EGR device 51, the low pressure EGR valve 37 is controlled to be opened, and the high pressure EGR valve 33 is feedback controlled. Preferably, the mixing ratio in the EGR gas from the high pressure EGR device 50 and the low pressure EGR device 51 is determined and controlled based on the intake air temperature detected by the intake air temperature sensor 16. Further, when the engine is cold (when the engine water temperature is equal to or lower than a predetermined temperature), the EGR gas is basically recirculated only by the high-pressure EGR device 50. The high pressure EGR device 50 and the low pressure EGR device 51 function as intake air temperature control means in the present invention.

  Hereinafter, an embodiment of the process performed by the ECU 70 will be specifically described.

[First Embodiment]
In the first embodiment, the motor generator MG is controlled according to the operating state so that the driving force of the hybrid vehicle 100 matches the required driving force, and the intake air temperature is controlled by the recirculation of EGR gas by the high-pressure EGR device 50. Thus, the intake air temperature detected by the intake air temperature sensor 16 is corrected so as to compensate for the response delay of the intake air temperature sensor 16. Specifically, the ECU 70 performs control to keep the engine load and rotation speed constant by the motor generator MG (for example, the second motor generator MG2) when only the high-pressure EGR device 50 is in operation, such as in the cold state. The intake air temperature is corrected by obtaining a time constant from the temperature change in the intake air temperature detected by the temperature sensor 16.

  The reason for performing such correction is as follows. In the system in which the EGR gas is recirculated by the two devices, the high pressure EGR device 50 and the low pressure EGR device 51, the EGR gas amount can be fed back and controlled under each single use condition. Controls the opening of the EGR valve provided on either side. In this case, in order to control the mixing ratio of both with high accuracy, it is important to control based on the intake air temperature. On the other hand, since the intake air temperature sensor 16 is provided at a location where the mixed gas of EGR gas from both is supplied, deposits such as soot in the burned gas by the high pressure EGR device 50 adhere to the sensor. As a result, the response performance may be deteriorated and the intake air temperature may be erroneously determined.

  Therefore, in the present embodiment, the ECU 70 corrects the intake air temperature detected by the intake air temperature sensor 16 in the procedure as described above. Specifically, the ECU 70 controls the motor generator MG to keep the engine load and the rotational speed constant when only the high-pressure EGR device 50 is in operation, such as during cold weather, and at the intake air temperature detected by the intake air temperature sensor 16. The intake air temperature is corrected by obtaining the time constant from the temperature change. When such control is performed, the ECU 70 compensates for the insufficient driving force that is generated by the output of the motor generator MG, and performs charge control during excessive power.

  More specifically, the ECU 70 determines whether or not a condition for operating only the high-pressure EGR device 50 is satisfied based on the engine water temperature or the like, and operates only the high-pressure EGR device 50 when the condition is satisfied. At the same time, the motor generator MG performs control to keep the engine load and the rotational speed constant. For example, the ECU 70 starts the idle operation of the engine 1. The ECU 70 monitors the intake air temperature detected by the intake air temperature sensor 16 during such control, calculates a time constant from the temperature difference after a predetermined time, and learns (hereinafter referred to as “intake air temperature sensor learned value”). Also called).

  Further, when the conditions for operating both the high pressure EGR device 50 and the low pressure EGR device 51 are satisfied, the ECU 70 fixes the rotation / load on the engine 1 side for a period determined by the above time constant and measures the intake air temperature. . During this time, the ECU 70 replenishes the increase in the driving force required by the driver with the output from the motor generator MG. If it cannot be replenished or if there is a decrease request, the ECU 70 immediately cancels the condition and sets the intake air temperature. The correction control is terminated. Next, if there is a deviation between the intake air temperature measured as described above and a map value (referred to as an intake air temperature defined in a predetermined map; the same applies hereinafter), the ECU 70 controls the low-pressure EGR valve 37. Calculate the correction amount of the opening. For example, the ECU 70 increases the correction amount of the opening degree of the low pressure EGR valve 37 as the deviation is larger. Then, the ECU 70 reflects the calculated correction amount as a learned value (hereinafter also referred to as “low pressure EGR valve opening learned value”).

  FIG. 3 is a flowchart showing the intake air temperature sensor learning process in the first embodiment. This process is repeatedly executed by the ECU 70 at a predetermined cycle.

  First, in step S101, the ECU 70 determines whether or not the operating condition of the high-pressure EGR device 50 is established based on the engine water temperature or the like. For example, the ECU 70 determines whether or not the engine is cold during light load operation. If the operating condition of the high-pressure EGR device 50 is satisfied (step S101; Yes), the process proceeds to step S102. If the operating condition of the high-pressure EGR device 50 is not satisfied (step S101; No), the process ends. To do.

  In step S102, the ECU 70 calculates the output Pa based on the accelerator request from the driver. That is, the required driving force is calculated. Then, the process proceeds to step S103.

  In step S103, the ECU 70 sets the engine speed to the idle speed based on the engine water temperature or the like. Further, ECU 70 calculates output Pm of motor generator MG so that output Pm of motor generator MG becomes the required output Pa (Pm = Pa). Then, the process proceeds to step S104.

  In step S104, the ECU 70 monitors the output of the intake air temperature sensor 16 and measures the temperature difference after a predetermined time. Then, the ECU 70 corrects the time constant based on the measured temperature difference. Thereafter, the ECU 70 updates the learning value (intake air temperature sensor learning value). Then, the process ends.

  FIG. 4 is a flowchart showing the low pressure EGR valve opening learning process in the first embodiment. This process is repeatedly executed at a predetermined cycle by the ECU 70 based on the value obtained by the process shown in FIG.

  First, in step S201, the ECU 70 determines whether or not a condition for operating both the high-pressure EGR device 50 and the low-pressure EGR device 51 is established based on the current operation state and the like. If the condition is satisfied (step S201; Yes), the process proceeds to step S202. If the condition is not satisfied (step S201; No), the process ends.

  In step S202, the ECU 70 sets a time constant Tc obtained by the process shown in FIG. Specifically, the ECU 70 fixes the rotation / load on the engine 1 side for a period determined by the time constant Tc. Then, the process proceeds to step S203.

  In step S203, the ECU 70 determines whether or not the elapsed time T from the start of this process has exceeded the time constant Tc. If the elapsed time T is greater than or equal to the time constant Tc (step S203; Yes), the process proceeds to step S204. If the elapsed time T is less than the time constant Tc (step S203; No), the process returns to step S203.

  In step S204, the ECU 70 measures the intake air temperature based on the output of the intake air temperature sensor 16, and compares the intake air temperature with the map value. Then, the ECU 70 corrects the opening degree of the low pressure EGR valve 37 if the difference between the intake air temperature and the map value is larger than the set value. Thereafter, the ECU 70 updates the learning value (low pressure EGR valve opening learning value). Then, the process ends.

  According to the first embodiment described above, even if the responsiveness of the intake air temperature sensor 16 is deteriorated due to deposit adhesion or the like, it is possible to appropriately correct the intake air temperature detected by the intake air temperature sensor 16. Specifically, when the temperature correction is performed in consideration of the time constant from the temperature change, the deficiency / excess of the driving force output from the engine 1 is compensated using the motor generator MG so as to obtain the required driving force. Therefore, it is possible to appropriately correct the intake air temperature detected by the intake air temperature sensor 16 without being influenced by the operating state. Therefore, it is possible to appropriately suppress emission deterioration and fuel consumption deterioration during the correction process.

[Second Embodiment]
Next, a second embodiment will be described. In the second embodiment, when only the high-pressure EGR device 50 is in operation, such as when cold, the motor generator MG performs control to keep the engine load and rotation speed constant, and the temperature change at the intake air temperature detected by the intake air temperature sensor 16 Then, the time constant is obtained and corrected, and the temperature on the high temperature side is corrected. Next, the engine load is increased, and the temperature correction on the low temperature side is performed when both the high pressure EGR valve 33 and the low pressure EGR valve 37 are opened. This is different from the first embodiment in that it is performed.

  More specifically, the ECU 70 calculates the time constant by monitoring the intake air temperature detected by the intake air temperature sensor 16 in the above-described procedure when only the high pressure EGR device 50 is operated. (Intake air temperature sensor learning value) is updated, the temperature sensor value on the high temperature side is compared with the map, and correction is made if necessary. Next, the ECU 70 increases the engine load, thereby changing the engine load to the operating region of both the high pressure EGR device 50 and the low pressure EGR device 51 and performing a constant operation. Then, the ECU 70 compares the temperature sensor value on the low temperature side when operating in this way with the map, and corrects it if necessary. This makes it possible to appropriately correct the temperature gain. In addition, after such correction | amendment, ECU70 performs the correction | amendment (refer FIG. 4) of the opening degree of the low pressure EGR valve 37 as shown in 1st Embodiment similarly.

  FIG. 5 is a flowchart showing an intake air temperature sensor time constant and gain learning process in the second embodiment. This process is repeatedly executed by the ECU 70 at a predetermined cycle.

  Since the process of steps S301 to S303 is the same as the process of steps S101 to S103 described above (see FIG. 3), the description thereof is omitted. If the operating condition of the high pressure EGR device 50 is not satisfied (step S301; No), the process proceeds to step S305.

  In step S304, the ECU 70 monitors the output of the intake air temperature sensor 16 and measures a temperature difference after a certain time (in this case, the measured intake air temperature tends to increase). Then, the ECU 70 corrects the time constant based on the measured temperature difference. Thereafter, the ECU 70 compares the temperature sensor value on the high temperature side with the map and corrects it if necessary. Then, the process proceeds to step S305.

  In step S <b> 305, the ECU 70 increases the engine load, thereby changing the engine load to the operation region of both the high pressure EGR device 50 and the low pressure EGR device 51 and performing a constant operation. In this case, when the low pressure EGR valve 37 is opened, both the high pressure EGR valve 33 and the low pressure EGR valve 37 are opened. Then, the process proceeds to step S306.

  In step S306, the ECU 70 monitors the output of the intake air temperature sensor 16 and measures a temperature difference after a certain time (in this case, the measured intake air temperature tends to decrease). Then, the ECU 70 compares the temperature sensor value on the low temperature side with the map based on the measured temperature difference, and corrects it if necessary. Then, the process ends.

  Also in the second embodiment described above, by compensating the driving force of the vehicle using the motor generator MG, the intake air temperature can be corrected without being influenced by the driving state, and the emission deterioration during the correction process , Fuel consumption deterioration can be appropriately suppressed. Further, according to the second embodiment, it is possible to appropriately correct the temperature gain.

1 engine (internal combustion engine)
16 Intake air temperature sensor 20 Intake air passage 23 Turbocharger 24 Intercooler 25 Exhaust air passage 27 DPF
33 High pressure EGR valve 37 Low pressure EGR valve 50 High pressure EGR device 51 Low pressure EGR device 70 ECU
100 Hybrid vehicle MG1 First motor generator MG2 Second motor generator

Claims (2)

An intake air temperature detection device for an internal combustion engine applied to a vehicle having an electric motor capable of at least one of regeneration and power running,
An intake air temperature sensor provided in the intake passage for detecting intake air temperature;
An intake air temperature control means for controlling the intake air temperature of the internal combustion engine by introducing either the cold air from the cold air supply source or the hot air from the hot air supply source into the intake passage;
The motor is controlled in accordance with the driving state so that the driving force of the vehicle matches the required driving force, and the control of the intake air temperature by the intake air temperature control means is executed, whereby the response of the intake air temperature sensor An intake air temperature detecting device for an internal combustion engine, comprising: an intake air temperature correcting means for correcting the intake air temperature detected by the intake air temperature sensor so as to compensate for the delay.   The intake air temperature detection device for an internal combustion engine according to claim 1, wherein the intake air temperature control means is an EGR device that recirculates a part of the exhaust gas discharged from the combustion chamber into the intake passage as EGR gas.

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