JP2005146941A - Control unit of vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain odor of sulfur in exhaust from an internal combustion engine. <P>SOLUTION: An engine ECU comprises a step (S100) for detecting temperature of a catalyst; a step (S180) for lowering actuation of an air-conditioner under a condition that the air-conditioner is turned on (in S160, NO) and temperature in a vehicle is within an allowable range when the catalyst is in high temperature (in S110, YES), fuel is cut (in S120, YES), and a number of revolution of the engine has tolerance till a fuel-cut recovery number of revolution (in S140, YES); a step for lowering actuation of an alternator (S210) when a charging condition of a secondary battery is within an allowable range (in S200, YES); and a step (S300) for outputting instructions to reduce pumping gross. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to control of an internal combustion engine mounted on a vehicle, and more particularly to control of an internal combustion engine that suppresses exhaust odor in exhaust that is purified by a catalyst and then released to the atmosphere.

Air pollutants are contained in the exhaust of the engine that is the driving source of the vehicle. Air pollutants combine carbon monoxide (CO) generated when fuel is incompletely combusted, hydrocarbons (HC) vaporized from unburned fuel, and nitrogen and oxygen in the air in a high-temperature combustion chamber. Nitrogen oxide (NOx). These are toxic to humans and must be removed before being released to the atmosphere. For this purpose, a catalytic converter is provided in the middle of the exhaust pipe. In this catalytic converter, platinum and rhodium, or palladium added thereto is used as a catalyst, so that all three types of air pollutants are carbon dioxide (CO ₂ ), water (H ₂ O, harmless to humans). ) And nitrogen (N ₂ ). It is also called a three-way catalyst because it reacts with three kinds of chemical substances.

In such a catalytic converter, 1) the catalyst temperature is high, 2) the exhaust gas amount is small (that is, the intake air amount is small), and the average air-fuel ratio after control is rich. If the conditions are satisfied, the inside of the catalytic converter becomes a reducing atmosphere, and exhaust odor (H ₂ S) is generated. That is, sulfur (S) contained in the fuel adheres to the catalyst as SOx due to the oxidation action, and when the above three conditions are met, the reduction action of SOx adsorbed under the reducing atmosphere works, and the sulfur odor ( H ₂ S) is generated.

  Japanese Patent Laid-Open No. 63-97844 (Patent Document 1) discloses an air-fuel ratio of an internal combustion engine that reliably detects an exhaust odor generation state and reduces the exhaust odor by setting the control average air-fuel ratio to a lean air-fuel ratio as intended. A control device is disclosed. This air-fuel ratio control apparatus for an internal combustion engine is provided with a first component that detects the concentration of a specific component in exhaust gas that is provided upstream and downstream of a catalytic converter for purifying exhaust gas provided in an exhaust system of the internal combustion engine. The second air-fuel ratio sensor, the catalyst temperature determining means for determining whether the temperature of the catalytic converter is high or low, the load determining means for determining whether the engine load is large or small, and when the temperature of the catalytic converter is low Alternatively, a first control constant calculating means for calculating an air-fuel ratio feedback control constant so that the control air-fuel ratio is directed toward the stoichiometric air-fuel ratio according to the output of the second air-fuel ratio sensor when the engine load is large; A second air-fuel ratio feedback control constant is calculated so that the control air-fuel ratio is directed toward the lean side according to the output of the second air-fuel ratio sensor when the temperature is high and the engine load is small. Control constant calculation means, air-fuel ratio correction amount calculation means for calculating the air-fuel ratio correction amount according to the output of the first air-fuel ratio sensor and the air-fuel ratio feedback control constant, and the air-fuel ratio of the engine according to the air-fuel ratio correction amount. Air-fuel ratio adjusting means for adjusting.

According to this air-fuel ratio control apparatus for an internal combustion engine, the downstream air-fuel ratio sensor is provided downstream of the catalytic converter, so that it can detect the air-fuel ratio of the exhaust gas mixed sufficiently. Therefore, the above three conditions can be reliably detected together with the catalyst temperature determining means and the load determining means. In this case, since the second control constant calculating means acts so that the control air-fuel ratio is directed toward the lean side, it is possible to reliably reduce exhaust odor and suppress deterioration of drivability, NOx emission, and the like.
Japanese Unexamined Patent Publication No. 63-97844

  However, in the air-fuel ratio control apparatus for an internal combustion engine disclosed in Patent Document 1, even if the above three conditions can be detected reliably, the second control constant calculation means thereafter causes the control air-fuel ratio to move toward the lean side. It's just what you do. That is, it is effective only for the third of the three conditions, and is a light load region where the catalyst temperature is high and the amount of exhaust gas is small (that is, the amount of intake air is small). Therefore, the generation of sulfur odor cannot be effectively suppressed.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a vehicle control device that can effectively suppress problems of the purification device such as generation of sulfur odor of exhaust gas. It is to be.

  According to a first aspect of the present invention, there is provided a vehicle control device that controls a vehicle equipped with a purification device that purifies exhaust gas discharged from an internal combustion engine. The control device detects when the vehicle state satisfies a predetermined condition, a fuel cut execution means for stopping fuel supply to the internal combustion engine, and a state in which exhaust purification by the purification device is insufficient. And a control means for controlling the vehicle so that the fuel supply stop period becomes longer when the detection means detects that the exhaust gas is not sufficiently purified.

According to the first aspect of the present invention, when the fuel cut is executed to stop the fuel supply, there is no fuel supplied to the internal combustion engine, so the air-fuel ratio becomes lean. The longer the fuel cut time, the leaner the air / fuel ratio. In order to lengthen the fuel cut time, it is necessary to maintain the rotational speed of the internal combustion engine at a relatively high rotational speed so that the rotational speed of the internal combustion engine does not decrease to a stalling rotational speed. For this purpose, for example, in order to reduce intake / exhaust loss (pumping loss) in the internal combustion engine, the electronic throttle valve is opened to increase the intake air amount. As the amount of intake air increases, the catalyst temperature decreases and the amount of exhaust gas also increases. As a result, 1) the catalyst temperature decreases, 2) the exhaust gas amount increases (ie, the intake air amount is large), and 3) the average air-fuel ratio after control becomes lean. In such a state, SOx adhering to the catalyst is not reduced under a reducing atmosphere, and sulfur odor (H ₂ S) is not generated. As a result, it is possible to provide a vehicle control device that can effectively suppress problems of the purification device such as generation of sulfur odor of exhaust gas.

  In the vehicle control apparatus according to the second invention, in addition to the structure of the first invention, the detection means includes means for detecting the temperature of the purification apparatus, and purification of exhaust gas when the detected temperature is high. Means for detecting that the state is insufficient.

According to the second aspect of the invention, the high temperature of the three-way catalyst, which is a purification device, contributes to the generation of sulfur odor (H ₂ S) by reducing SOx adhering to the catalyst under a reducing atmosphere. For this reason, since the vehicle is controlled so that the generation of sulfur odor, which is considered to be insufficient in purification of exhaust gas by the purification device, is suppressed, the generation of sulfur odor is suppressed and the driver and passenger of the vehicle are not uncomfortable. .

  In the vehicle control apparatus according to the third aspect of the invention, in addition to the configuration of the first or second aspect of the invention, the state in which exhaust purification is insufficient is a state in which an exhaust odor is generated.

According to the third aspect of the invention, the SOx adhering to the catalyst is reduced under a reducing atmosphere to generate a sulfur odor (H ₂ S), and the vehicle driver and passenger feel an exhaust odor. Generation | occurrence | production of this exhaust odor can be suppressed.

  In the vehicle control apparatus according to the fourth invention, in addition to the configuration of any one of the first to third inventions, the control means controls the vehicle so as to reduce the mechanical loss of the internal combustion engine. Includes mechanical loss reduction means.

  According to the fourth invention, the control means reduces the load on the internal combustion engine by stopping the operation of the compressor or alternator of the air conditioner connected via the belt to the drive shaft of the internal combustion engine, which is a mechanical loss of the internal combustion engine. be able to. When the mechanical loss of the internal combustion engine is reduced, a decrease in the rotational speed of the internal combustion engine is suppressed during the fuel cut, and the fuel cut time is extended. The longer the fuel cut time is, the more the exhaust odor can be suppressed, and the fuel efficiency of the vehicle can be improved.

  In the vehicle control apparatus according to the fifth aspect of the invention, in addition to the configuration of the fourth aspect of the invention, a machine operated by the driving force of the internal combustion engine is connected to the output shaft of the internal combustion engine. Means for reducing the load on the machine.

  According to the fifth aspect of the present invention, the load on the internal combustion engine is reduced by stopping the operation of the compressor and alternator of the air conditioner that is mounted on the vehicle and operated by the internal combustion engine, or reducing the operation state. be able to. When the mechanical loss of the internal combustion engine is reduced, a decrease in the rotational speed of the internal combustion engine is suppressed during the fuel cut, and the fuel cut time is extended. The longer the fuel cut time is, the more the exhaust odor can be suppressed, and the fuel efficiency of the vehicle can be improved.

  In the vehicle control apparatus according to the sixth aspect of the invention, in addition to the configuration of the fifth aspect of the invention, the vehicle is equipped with an air conditioner that adjusts the vehicle interior temperature, and the machine is a machine that drives the air conditioner. The mechanical loss reducing means includes means for reducing the load on the machine when the in-vehicle temperature is within an allowable range.

  According to the sixth invention, the target temperature set in the air conditioner (cooling device) is compared with the current temperature, and if the vehicle interior temperature is within the allowable range (target temperature (25 ° C.) + Α (3 ° C.) ≧ If the current temperature (27 ° C. or the like), the operation of the air conditioner compressor is kept low or stopped. As a result, the mechanical loss of the internal combustion engine is reduced, the decrease in the rotational speed of the internal combustion engine is suppressed during the fuel cut, and the fuel cut time is extended. The longer the fuel cut time is, the more the exhaust odor can be suppressed and the fuel consumption of the vehicle can be improved. At this time, if the temperature in the passenger compartment is not within the allowable range, such control is not performed, so that the driver and the passenger are not uncomfortable.

  In the vehicle control device according to the seventh aspect of the invention, in addition to the configuration of the fifth aspect of the invention, the vehicle is equipped with a secondary battery that supplies electric power to the electrical equipment of the vehicle, The mechanical loss reducing means includes a means for reducing the load on the machine when the remaining capacity of the secondary battery is within an allowable range.

  According to the seventh aspect of the invention, the remaining capacity of the secondary battery is detected, and if the remaining capacity is greater than the allowable range, the operation of the alternator, which is a power generation device operated by the internal combustion engine, is suppressed or stopped. . As a result, the mechanical loss of the internal combustion engine is reduced, the decrease in the rotational speed of the internal combustion engine is suppressed during the fuel cut, and the fuel cut time is extended. The longer the fuel cut time is, the more the exhaust odor can be suppressed, and the fuel efficiency of the vehicle can be improved. At this time, if the remaining capacity of the secondary battery is not within the allowable range, such control is not performed, and thus the capacity of the secondary battery is not insufficient.

  In the vehicle control apparatus according to the eighth invention, in addition to the configuration of any one of the first to third inventions, the control means controls the vehicle so as to reduce loss due to intake and exhaust in the internal combustion engine. Includes intake / exhaust loss reduction means.

  According to the eighth invention, the pumping loss, which is a loss due to intake and exhaust of the internal combustion engine, can be reduced by the control means. When the loss due to intake and exhaust of the internal combustion engine is reduced, a decrease in the rotational speed of the internal combustion engine is suppressed during the fuel cut, and the fuel cut time is extended. The longer the fuel cut time is, the more the exhaust odor can be suppressed, and the fuel efficiency of the vehicle can be improved.

  In the vehicle control apparatus according to the ninth aspect of the invention, in addition to the configuration of the eighth aspect of the invention, the intake / exhaust loss reducing means controls to open a control valve that adjusts the amount of air supplied to the internal combustion engine. Including means.

According to the ninth aspect of the invention, for example, when an electronic throttle valve that is a control valve is opened, a large amount of air is supplied to the purification device through the internal combustion engine. At this time, by opening the electronic throttle valve, the pumping loss in the intake stroke is reduced as compared to when the electronic throttle valve is not opened. Thereby, the fall of the rotation speed of an internal combustion engine is suppressed during fuel cut, and fuel cut time is extended. As the fuel cut time becomes longer, the air-fuel ratio becomes leaner, so that the generation of exhaust odor can be suppressed and the fuel efficiency of the vehicle can be improved. Further, since a large amount of air passes through the internal combustion engine and is supplied to the purification device and fuel is not supplied to the internal combustion engine, a leaner state is achieved and the purification device is cooled by the large amount of air. Thereby, SOx adhering to the catalyst is not reduced under a reducing atmosphere, and sulfur odor (H ₂ S) is not generated.

  In the vehicle control apparatus according to the tenth aspect of the invention, in addition to the configuration of the eighth aspect of the invention, the intake / exhaust loss reduction means adjusts the opening / closing timing of the intake / exhaust valves of the internal combustion engine so that both valves are opened. Means for controlling to be in a state of being.

  According to the tenth invention, for example, the pumping loss in the intake stroke and the exhaust stroke can be reduced by extending the time during which both the intake and exhaust valves are open. Thereby, the fall of the rotation speed of an internal combustion engine is suppressed during fuel cut, and fuel cut time is extended. As the fuel cut time becomes longer, the air-fuel ratio becomes leaner, so that the generation of exhaust odor can be suppressed and the fuel efficiency of the vehicle can be improved.

  In the vehicle control apparatus according to the eleventh aspect of the invention, in addition to the configuration of the eighth aspect of the invention, the intake / exhaust loss reducing means adjusts the shift amount of the intake / exhaust valve of the internal combustion engine so that the shift amount increases. Means for controlling.

  According to the eleventh aspect, for example, the pumping loss in the intake stroke and the exhaust stroke can be reduced by increasing the shift amount of the intake / exhaust valve. Thereby, the fall of the rotation speed of an internal combustion engine is suppressed during fuel cut, and fuel cut time is extended. As the fuel cut time becomes longer, the air-fuel ratio becomes leaner, so that the generation of exhaust odor can be suppressed and the fuel efficiency of the vehicle can be improved.

  In the vehicle control apparatus according to the twelfth aspect of the invention, in addition to the configuration of the eighth aspect of the invention, the vehicle is equipped with a silencer capable of changing the ventilation resistance. Means are included for controlling the resistance to decrease.

  According to the twelfth aspect of the invention, the intake / exhaust loss reducing means controls so as to reduce the ventilation resistance of the silencer, so that the pumping loss in the exhaust stroke in the internal combustion engine can be reduced. Thereby, the fall of the rotation speed of an internal combustion engine is suppressed during fuel cut, and fuel cut time is extended. As the fuel cut time becomes longer, the air-fuel ratio becomes leaner, so that the generation of exhaust odor can be suppressed and the fuel efficiency of the vehicle can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  A vehicle control system according to an embodiment of the present invention will be described. In the following, a vehicle control system in a vehicle equipped with only an engine will be described, but the present invention is not limited to this. For example, it may be a hybrid vehicle having an engine and a rotating electrical machine (having a motor function and a generator function).

  FIG. 1 shows an overall control block diagram of the vehicle control system according to the present embodiment.

  As shown in FIG. 1, the vehicle powertrain includes an engine 100, a torque converter 200 whose input shaft is connected to the output shaft of the engine 100, and a gear type whose input shaft is connected to the output shaft of the torque converter. Transmission mechanism 300. Instead of the gear-type transmission mechanism 300, a belt-type or toroidal-type continuously variable transmission mechanism may be used.

  Air is sucked into the engine 100 through the intake pipe 120, and the sucked air becomes a mixture with the fuel supplied from the fuel injection system and burns in the engine 100, and the exhaust gas passes through the exhaust pipe 130. Exhausted.

  The intake side pipe line 120 is provided with an electronic throttle valve 110 that controls the amount of intake air. Further, the exhaust line 130 includes a three-way catalyst 140 that purifies carbon monoxide, hydrocarbons, and nitrogen oxides, which are air pollutants contained in the exhaust of the engine 100, and a muffler for reducing exhaust noise. 150 is arranged.

  A crankshaft pulley 402 is provided on the crankshaft of engine 100. This crankshaft pulley 402 is provided with a belt 410 that drives an alternator pulley 400 and an air conditioner compressor pulley 404. Alternator pulley 400 is connected to the rotating shaft of alternator 3000 and is used to operate alternator 3000 by the driving force of engine 100. Air conditioner compressor pulley 404 is connected to the rotating shaft of air conditioner compressor 4000 and is used to operate air conditioner compressor 4000 by the driving force of engine 100.

  An IC (Integrated Circuit) regulator 3100 is connected to the alternator 3000, and the power generation amount of the alternator 3000 is controlled based on a signal from an engine ECU (Electronic Control Unit) 1000 described later. In addition, for air conditioner compressor 4000, the operating state of air conditioner compressor 4000 is controlled based on a control signal from engine ECU 1000.

  Alternator 3000 is a general alternator, and when an internal rotor (rotor coil) is energized, an electric current is generated in an outer stator coil, which is taken out and charged to secondary battery 2000. The IC regulator 3100 controls energization to the rotor coil of the alternator 3000. By controlling the energization / non-energization of the rotor coil by turning on / off the transistor in the IC regulator 3100, the alternator can be activated or deactivated.

  The engine ECU 1000 that controls such a vehicle control system includes a voltage value from the voltage sensor of the secondary battery 2000, a charge / discharge current value from the current sensor 2100 of the secondary battery 2000, and a temperature sensor provided in the three-way catalyst 140. Respective signals representing the engine temperature and the engine temperature are input from the catalyst temperature and the engine speed sensor provided in the engine 100. In addition, a fuel cut start condition is input to engine ECU 1000, or a vehicle interior temperature or a set temperature of an air conditioner is input.

  Further, engine ECU 1000 outputs a power generation command signal (Hi / Lo) to IC regulator 3100 of alternator 3000, and an air conditioner control signal (Hi / Lo) to air conditioner compressor 4000. A valve timing control signal and a valve shift amount control signal are output from engine ECU 1000 to engine 100. An electronic throttle opening signal is output from engine ECU 1000 to electronic throttle 1100. A muffler exhaust valve command signal is output from engine ECU 1000 to muffler 150.

  The electronic throttle valve 110 adjusts the opening of the electronic throttle valve 110 based on the electronic throttle opening signal input from the engine ECU 1000 and controls the intake air amount. Engine 100 controls the opening / closing timing of intake / exhaust valves of engine 100 and the shift amount of intake / exhaust valves based on the valve timing control signal and valve shift amount control signal input from engine ECU 1000.

  The muffler 150 incorporates a variable valve that is opened and closed by an actuator that is operated by the engine ECU 1000. When the valve is closed, the muffler 150 allows a small diameter to pass to increase the expansion ratio and increase the silencing performance, and to open the valve. This is a muffler having a variable valve that can improve the output by reducing the ventilation resistance by passing through a large-diameter pipe. The muffler 150 can reduce ventilation resistance by passing a pipe having a large diameter by opening a variable valve based on a muffler exhaust valve command signal input from the engine ECU 1000.

  Engine ECU 1000 also determines the remaining capacity (SOC: States Of Charge) of secondary battery 2000 based on the voltage value input from the voltage sensor of secondary battery 2000 and the charge / discharge current value input from current sensor 2100. Can be calculated by calculation. Engine ECU 1000 has a memory for storing a program executed by engine ECU 1000, parameters used in the program, and the like.

  A control structure of a program executed by engine ECU 1000 of FIG. 1 will be described with reference to FIG.

  In step (hereinafter step is abbreviated as S) 100, engine ECU 1000 detects the catalyst temperature. At this time, engine ECU 1000 detects the catalyst temperature based on a signal representing the catalyst temperature input from the temperature sensor provided in three-way catalyst 140.

  In S110, engine ECU 1000 determines whether or not three-way catalyst 140 is at a high temperature. If temperature of three-way catalyst 140 is high (YES in S110), the process proceeds to S120. If not (NO in S110), the process proceeds to S400.

  In S120, engine ECU 1000 determines whether or not a fuel cut is in progress. This determination is made based on whether engine ECU 1000 outputs a fuel cut signal as a result of determination by engine ECU 1000 based on the fuel cut start condition input to engine ECU 1000. If the fuel is being cut (YES in S120), the process proceeds to S130. If not (NO in S120), the process proceeds to S400.

  In S130, engine ECU 1000 detects engine speed NE. At this time, engine ECU 1000 detects engine speed NE based on a signal representing the engine speed input from a speed sensor provided on the output shaft of engine 100.

  In S140, engine ECU 1000 determines whether engine speed NE is a speed that has a margin to the fuel cut return speed. This determination is made by engine ECU 1000 based on the engine speed input from the engine speed sensor of engine 100, the engine speed that is one of the fuel cut start conditions, and the engine speed that is the fuel cut end condition. It is. If it is determined that engine speed NE has a margin up to the fuel cut return speed (YES in S140), the process proceeds to S150. If not (NO in S140), the process proceeds to S400.

  In S150, engine ECU 1000 determines whether or not the brake is off. This determination is made based on a signal representing a brake state as a running state, which is one of the fuel cut start conditions input to engine ECU 1000. If the brake is off (YES in S150), the process proceeds to S160. If not (NO in S150), the process proceeds to S400.

  In S160, engine ECU 1000 determines whether or not the air conditioner is off. This determination is made based on a signal representing the operating state of the air conditioner input to engine ECU 1000. If the air conditioner is off (YES in S160), the process proceeds to S190. If not (NO in S160), the process proceeds to S170.

  In S170, engine ECU 1000 determines whether or not the in-vehicle temperature is within an allowable range. This determination is made by comparing a signal representing the in-vehicle temperature input to engine ECU 1000 with a signal representing the set temperature. If the in-vehicle temperature is within the allowable range (YES in S170), the process proceeds to S180. If not (NO in S170), the process proceeds to S190.

  In S180, engine ECU 1000 outputs an air conditioner Lo instruction signal to air conditioner compressor 4000. As a result, the air conditioner compressor 4000 operates the air conditioner compressor 4000 with a light load. After the process of S180, the process proceeds to S190.

  In S190, engine ECU 1000 determines whether or not power generation by alternator 3000 is off. If power generation by alternator 3000 is off (YES in S190), the process proceeds to S300. If not (NO in S190), the process proceeds to S200.

  In S200, engine ECU 1000 determines whether or not the state of charge is within an allowable range. At this time, engine ECU 1000 determines the remaining capacity (SOC) of secondary battery 2000 based on the voltage value of secondary battery 2000 and the charge / discharge current value detected by current sensor 2100 of secondary battery 2000. (SOC) and a predetermined threshold value (when the secondary battery 2000 is a lead storage battery, the SOC is approximately 90%). If the state of charge is within the allowable range (YES in S200), the process proceeds to S210. If not (NO in S200), the process proceeds to S300.

  In S210, engine ECU 1000 outputs a signal that uses the alternator 3000 power generation command signal as a Lo instruction to IC regulator 3100 of alternator 3000. After the process of S210, the process proceeds to S300.

  In S300, engine ECU 1000 outputs an instruction to open electronic throttle valve 110 to electronic throttle valve 110. Further, engine ECU 1000 outputs a signal for instructing the timing of the engine intake / exhaust valve to engine 100 (instruction for timing at which both intake and exhaust valves are open). Engine ECU 1000 also outputs an instruction to increase the shift amount of the engine intake / exhaust valve. Further, engine ECU 1000 outputs to muffler 150 a signal indicating an instruction to open the muffler exhaust valve.

  In S400, engine ECU 1000 executes normal control without outputting an instruction signal for performing the control shown in S300.

  The operation of the vehicle equipped with the vehicle control system according to the present embodiment based on the structure and flowchart as described above will be described.

  While the vehicle is running, the air amount controlled by the electronic throttle valve 110 is supplied to the engine 100 via the intake pipe 120 to the engine 100, and fuel is supplied by the fuel supply system so that the engine 100 is operated. Exhaust gas generated by the exhaust gas 100 is exhausted through the exhaust pipe 130 to the atmosphere via the three-way catalyst 140 and the muffler 150. When the engine 100 is being driven, the crankshaft pulley 402 connected to the crankshaft of the engine 100 rotates, and the rotational force of the crankshaft pulley 402 causes the belt 410 to rotate the alternator pulley 400 and the air conditioner compressor pulley 404. As a result, the alternator 3000 and the air conditioner compressor 4000 are activated.

  The temperature of the three-way catalyst 140 provided in the middle of the exhaust pipe 130 is detected (S100). If the temperature is high (YES in S110), it is determined whether or not a fuel cut is being performed (YES in S110). S120). If the fuel is being cut (YES in S120), engine speed NE is detected (S130). If it is determined that engine speed NE has a margin up to the fuel cut return speed (YES in S140), it is determined whether or not the brake is off. It is determined whether the brake is off (YES in S150), whether the air conditioner (air conditioner compressor 4000) is off (S160), and whether alternator 3000 is in the power generation state (S190). . If the air conditioner is in operation (NO in S160), it is determined whether the in-vehicle temperature is within an allowable range (S170). If the in-vehicle temperature is within the allowable range (YES in S170), an instruction is output to air conditioner compressor 4000 such that the air conditioner control signal causes the operating state of air conditioner compressor 4000 to be in a low state (S180).

  If the charged state of secondary battery 2000 is within the allowable range (YES in S200), a signal for stopping power generation by alternator 3000 is output to IC regulator 3100 of alternator 3000 (S210).

  That is, when the in-vehicle temperature is within the allowable range and the charged state of the secondary battery 2000 is within the allowable range, the operating state of the air conditioner compressor 4000 is reduced (or stopped), or the power generation state of the alternator 3000 is reduced. Is reduced (or stopped).

  The operation state of the air conditioner compressor 4000 and the alternator 3000 is changed to reduce the mechanical load of the engine 100, and an instruction to open the electronic throttle valve 110 is output, and the intake / exhaust valve timing of the engine 100 is set. An instruction is output so that both the intake and exhaust valves are open, an instruction to increase the shift amount of the engine intake and exhaust valves is output, and a path on the large diameter side of the muffler 150 is opened. An instruction to open the exhaust valve is output (S300).

  By controlling the electronic throttle valve 110 to open, the opening of the electronic throttle valve 110 is increased, and the pumping loss in the intake stroke of the engine 100 is reduced. When the intake / exhaust valve timing of the engine 100 is changed and a time during which both the intake / exhaust valves are open is set or the shift amount of the engine intake / exhaust valve is increased, the pump loss in the intake stroke and exhaust stroke of the engine is reduced. . Further, when the exhaust valve of the muffler 150 is opened, the ventilation resistance is reduced by the exhaust passing through the large-diameter path.

  With reference to FIG. 3 and FIG. 4, the operation of this vehicle control system will be described using a timing chart.

FIG. 3 shows a fuel cut flag, an air conditioner operation flag, a shift (gear stage of the gear type transmission mechanism 300), an H ₂ S concentration, an engine speed NE, a fuel cut return speed, and a vehicle speed in a conventional vehicle control system. As shown in FIG. 3, the air conditioner operation flag is in the Hi state, and the air conditioner is continuously operating. Similarly to the air conditioner, power generation by the alternator 3000 is continuously performed, the electronic throttle valve 110 is not actively opened, and both the engine intake and exhaust valve timings are actively opened. FIG. 3 shows a case where the control is not performed so that the shift amount of the engine intake / exhaust valve is positively increased, and the muffler exhaust valve is not controlled to be actively opened. The timing chart is as shown.

  When the fuel cut starts in such a state, as shown in FIG. 3, it is a mechanical loss, 1) a load of the air conditioner compressor 4000, 2) a load of the alternator 3000, or a pumping loss, and 3) an electronic throttle valve 110. 4) Intake / exhaust stroke caused by the fact that the intake / exhaust valve of the engine 100 is not controlled so that both of the intake / exhaust valves are forcibly opened or forcibly increased. Pumping loss, 5) A pumping loss of the exhaust system due to the variable valve of the muffler 150 not being opened occurs. For this reason, after the fuel cut is started, the engine speed NE is rapidly reduced.

When the engine speed NE falls below the fuel cut return speed, the engine is returned from the fuel cut and the engine speed NE starts to increase. Since the vehicle is in an idling state, the vehicle speed is gradually lowered and the vehicle is stopped. However, the catalyst is hot, the amount of exhaust gas is small, and the H ₂ S concentration has a lower limit of H ₂ S sensation when the vehicle is stopped. The vehicle driver and the passenger feel a sulfur smell.

  On the other hand, as shown in FIG. 4, in the vehicle control system according to the present embodiment, when the temperature inside the vehicle is within the allowable range when the air conditioner is operating during fuel cut, the air conditioner compressor 4000 is used. An instruction is output to lower the operating state of.

  At this time, in addition to the control of the air conditioner, control to stop the power generation instruction of the alternator 3000, control to open the electronic throttle valve 110, and timing of the intake and exhaust valves of the engine 1000 are performed. Control is performed such that both the intake valve and the exhaust valve are open, control is performed so that the shift amount of the intake / exhaust valve of the engine 100 is increased, and control is performed so that the exhaust valve of the muffler 150 is opened. By doing so, mechanical loss and pumping loss are reduced. Therefore, as shown in FIG. 4, after the fuel cut has started, the engine speed NE can be gently decreased.

  In other words, since control for reducing mechanical loss and pumping loss of an air conditioner or the like was not performed, the engine speed NE suddenly decreased as indicated by the dotted line, but in the vehicle control system according to the present embodiment, Since the mechanical loss and the pumping loss are reduced to reduce the load of the engine 100, the engine speed NE is gradually decreased after the fuel cut, and the fuel cut time is extended.

At this time, it is possible to maintain a lean state of the air-fuel ratio by extending the fuel cut time itself. Further, since the electronic throttle valve is opened to increase the amount of intake air, the catalyst temperature decreases and the exhaust gas increases. As a result, the catalyst temperature decreases, the exhaust gas increases, and the average air-fuel ratio becomes lean. In such a state, it is possible to suppress the SO _X attached to the three-way catalyst 140 is reduced under reducing atmosphere of sulfur odor (H ₂ S) is generated. For this reason, when the vehicle is stopped as shown in FIG. 4, the H ₂ S concentration is below the lower limit of H ₂ S sensation that can be felt by the driver and the passenger of the vehicle. No longer feel sulfur smell.

As described above, according to the vehicle control system according to the present embodiment, in the catalyst, in the light load region where the catalyst temperature is high and the amount of exhaust gas is small and the air-fuel ratio is rich, the exhaust odor ( H ₂ S) is generated. In order to lengthen the time during which the fuel cut performed in the idle state is executed, by reducing the operating state of the air conditioner and alternator, which is a mechanical loss connected to the engine, or by eliminating the pumping loss, Fuel cut time can be extended. By extending the fuel cut time, the time during which the lean state continues is increased, the amount of intake air increases, and the temperature of the catalyst also decreases. As a result, it is possible to effectively suppress the generation of sulfur odor and improve fuel efficiency.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is an overall control block diagram of a vehicle control system according to an embodiment of the present invention. It is a flowchart which shows the control structure of the program performed by engine ECU of FIG. It is a timing chart showing operation | movement of the vehicle carrying the conventional vehicle control system. It is a timing chart showing operation | movement of the vehicle carrying the vehicle control system which concerns on embodiment of this invention.

Explanation of symbols

  100 Engine, 110 Electronic throttle valve, 120 Intake line, 130 Exhaust line, 140 Three-way catalyst, 150 Muffler, 200 Torque converter, 300 Gear-type transmission mechanism, 400 Alternator pulley, 402 Crankshaft pulley, 404 Air conditioner compressor pulley, 410 belt, 1000 engine ECU, 2000 secondary battery, 2100 current sensor, 3000 alternator, 3100 IC regulator, 4000 air conditioner compressor.

Claims (12)

A vehicle control device equipped with a purification device for purifying exhaust gas discharged from an internal combustion engine,
A fuel cut executing means for stopping the fuel supply to the internal combustion engine when the state of the vehicle satisfies a predetermined condition;
Detection means for detecting a state in which exhaust purification by the purification device is insufficient;
And a control unit configured to control the vehicle so that a fuel supply stop period becomes long when the detection unit detects that the exhaust gas is not sufficiently purified. The detection means includes
Means for detecting the temperature of the purification device;
The vehicle control device according to claim 1, further comprising means for detecting that exhaust gas purification is in an insufficient state when the detected temperature is high.   The vehicle control device according to claim 1 or 2, wherein the state where the exhaust purification is insufficient is a state where an exhaust odor is generated.   The vehicle control device according to claim 1, wherein the control means includes mechanical loss reduction means for controlling the vehicle so as to reduce mechanical loss of the internal combustion engine. A machine operated by the driving force of the internal combustion engine is connected to the output shaft of the internal combustion engine,
The vehicle control device according to claim 4, wherein the mechanical loss reducing means includes means for reducing a load on the machine. The vehicle is equipped with an air conditioner that adjusts the interior temperature of the vehicle,
The machine is a machine that drives the air conditioner,
The vehicle control device according to claim 5, wherein the mechanical loss reducing means includes means for reducing a load on the machine when the in-vehicle temperature is within an allowable range. The vehicle is equipped with a secondary battery that supplies power to the electrical equipment of the vehicle,
The machine is a machine that generates electric power for charging the secondary battery,
The vehicle control device according to claim 5, wherein the mechanical loss reducing means includes means for reducing the load on the machine when the remaining capacity of the secondary battery is within an allowable range.   The vehicle control device according to claim 1, wherein the control means includes intake / exhaust loss reduction means for controlling the vehicle so as to reduce loss due to intake and exhaust in the internal combustion engine.   The vehicle control device according to claim 8, wherein the intake / exhaust loss reducing means includes means for controlling to open a control valve for adjusting an amount of air supplied to the internal combustion engine.   9. The vehicle according to claim 8, wherein the intake / exhaust loss reducing means includes means for adjusting an opening / closing timing of an intake / exhaust valve of the internal combustion engine so as to control both valves to be in an open state. Control device.   The vehicle control device according to claim 8, wherein the intake / exhaust loss reducing means includes means for adjusting a shift amount of an intake / exhaust valve of the internal combustion engine to control the shift amount to increase. The vehicle is equipped with a silencer capable of changing the ventilation resistance,
The vehicle control device according to claim 8, wherein the intake / exhaust loss reduction means includes means for controlling the ventilation resistance of the silencer to decrease.

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