JP7505384B2 - Engine equipment - Google Patents

Description

The present invention relates to an engine device.

Conventionally, this type of engine device has been proposed to have an engine and a purification catalyst that purifies the engine exhaust, and to execute catalyst warm-up control to control the engine to achieve a certain target output when a request to warm up the purification catalyst is made (see, for example, Patent Document 1).

JP 2014-210566 A

In such an engine device, when exhaust limit control is executed to limit the amount of engine displacement after engine start, it is considered to control the engine based on the start temperature, which is the temperature of the engine when the engine start is completed. The exhaust limit control is executed to suppress the deterioration of emissions when the purification catalyst is inactive. However, up until now, exhaust limit control has not been executed after the engine has returned from a fuel cut. When executing exhaust limit control after the engine has returned from a fuel cut, it is considered to control the engine based on the start temperature, just as when exhaust limit control is executed after the engine has started. However, if there is a large discrepancy between the start temperature and the engine temperature when exhaust limit control is executed after the engine has returned from a fuel cut, there is a possibility that the exhaust limit control after the engine has returned from a fuel cut cannot be executed appropriately.

The main purpose of the engine device of the present invention is to more appropriately execute exhaust limit control when the exhaust limit control is executed after the engine returns from a fuel cut.

The engine device of the present invention employs the following means to achieve the above-mentioned main objective.

The engine device of the present invention comprises:
An engine device including an engine, a purification catalyst that purifies exhaust gas from the engine, and a control device that controls the engine,
The control device includes:
When executing a first exhaust restriction control that is an exhaust restriction control for restricting an exhaust amount of the engine after the engine is started, the engine is controlled based on a first temperature that is a temperature of the engine at the start of the first exhaust restriction control;
When executing a second exhaust restriction control, which is the exhaust restriction control after the engine returns from a fuel cut, the engine is controlled based on a second temperature, which is the temperature of the engine at the start of the second exhaust restriction control.
The gist of the present invention is as follows.

In the engine device of the present invention, when the first exhaust restriction control, which is an exhaust restriction control that limits the engine exhaust volume after the engine is started, is executed, the engine is controlled based on the first temperature, which is the temperature of the engine at the start of the first exhaust restriction control, and when the second exhaust restriction control, which is an exhaust restriction control after the engine returns from fuel cut, is executed, the engine is controlled based on the second temperature, which is the temperature of the engine at the start of the second exhaust restriction control. As a result, when the second exhaust restriction control is executed, the engine can be controlled by more appropriately reflecting the engine state at that time, so that the engine can be more appropriately controlled. As a result, the second exhaust restriction control can be more appropriately executed. Here, an example of a time when the exhaust restriction control is executed is when the temperature of the purification catalyst is below a threshold value. For example, the first temperature is the temperature of the engine when the engine is started. For example, the second temperature is the temperature of the engine when the engine returns from fuel cut (when fuel injection is resumed).

In the engine device of the present invention, the control device may control the engine by setting at least one of the target output, the target equivalence ratio, and the target ignition timing based on the first temperature when executing the first exhaust restriction control, and may control the engine by setting at least one of the target output, the target equivalence ratio, and the target ignition timing based on the second temperature when executing the second exhaust restriction control. In this way, at least one of the target output, the target equivalence ratio, and the target ignition timing can be set more appropriately.

In the engine device of the present invention, the control device may control the engine based on the first temperature and a first accumulated air volume, which is an accumulated value of the intake air volume since the start of the first exhaust restriction control, when executing the first exhaust restriction control, and control the engine based on the second temperature and a second accumulated air volume, which is an accumulated value of the intake air volume since the start of the second exhaust restriction control, when executing the second exhaust restriction control. In this way, the first exhaust restriction control and the second exhaust restriction control can be executed more appropriately.

In the engine device of the present invention, the control device may execute, as the exhaust restriction control, lean control for controlling the engine so that the equivalence ratio is smaller than a value of 1, and rich control for controlling the engine so that the equivalence ratio is larger than a value of 1, in that order. In this case, the control device may transition to the rich control in the first exhaust restriction control when a first accumulated air amount, which is an accumulated value of the intake air amount from the start of the first exhaust restriction control, reaches a first threshold value or more during execution of the lean control, and transition to the rich control in the second exhaust restriction control when a second accumulated air amount, which is an accumulated value of the intake air amount from the start of the second exhaust restriction control, reaches a second threshold value or more during execution of the lean control.

1 is a diagram showing an outline of the configuration of a hybrid vehicle 20 equipped with an engine device 21 according to an embodiment of the present invention. 2 is an explanatory diagram showing an outline of the configuration of an engine device 21. FIG. 4 is a flowchart showing an example of a catalyst warm-up control routine executed by an engine ECU 24. This is an explanatory diagram showing an example of the engine 22 rotation speed Ne, whether or not fuel cut is performed, the temperature Tc of the purification catalyst 135a, whether or not catalyst warm-up control is performed, the cooling water temperature Tw, the first accumulated air amount Qas1, the second accumulated air amount Qas2, the target power Pe*, the target equivalence ratio φ*, and the target ignition timing IT*.

Next, we will explain how to implement the present invention using examples.

Fig. 1 is a schematic diagram showing the configuration of a hybrid vehicle 20 equipped with an engine device 21 according to one embodiment of the present invention, and Fig. 2 is an explanatory diagram showing the schematic configuration of the engine device 21. As shown in Fig. 1, the hybrid vehicle 20 of the embodiment includes the engine device 21, a planetary gear 30, motors MG1 and MG2, inverters 41 and 42, a battery 50, and a hybrid electronic control unit (hereinafter referred to as HVECU) 70. Here, the engine device 21 has an engine 22 and an engine electronic control unit (hereinafter referred to as "engine ECU") 24.

The engine 22 is configured as a four-cylinder internal combustion engine that uses fuel such as gasoline or diesel and outputs power through four strokes: intake, compression, expansion (explosive combustion), and exhaust. As shown in FIG. 2, the engine 22 has a port injection valve 126 that injects fuel into the intake port and an in-cylinder injection valve 127 that injects fuel into the cylinder. The engine 22 can be operated in any of the port injection mode, the in-cylinder injection mode, and the shared injection mode by having the port injection valve 126 and the in-cylinder injection valve 127. In the port injection mode, air cleaned by the air cleaner 122 is sucked into the intake pipe 123 and passes through the throttle valve 124 and the surge tank 125, and fuel is injected from the port injection valve 126 downstream of the surge tank 125 of the intake pipe 123 to mix the air and the fuel. This mixture is then drawn into the combustion chamber 129 via the intake valve 128, where it is explosively combusted by an electric spark from the spark plug 130, and the reciprocating motion of the piston 132, which is pushed down by the energy of the mixture, is converted into the rotational motion of the crankshaft 23. In the in-cylinder injection mode, air is drawn into the combustion chamber 129 in the same manner as in the port injection mode, and fuel is injected from the in-cylinder injection valve 127 during the intake stroke and/or after the compression stroke, and is explosively combusted by an electric spark from the spark plug 130 to obtain the rotational motion of the crankshaft 23. In the shared injection mode, fuel is injected from the port injection valve 126 when air is drawn into the combustion chamber 129, and fuel is injected from the in-cylinder injection valve 127 during the intake stroke or compression stroke, and is explosively combusted by an electric spark from the spark plug 130 to obtain the rotational motion of the crankshaft 23. These injection modes are switched based on the operating state of the engine 22. Exhaust discharged from the combustion chamber 129 to the exhaust pipe 134 through the exhaust valve 133 is discharged to the outside air through the purification device 135. The purification device 135 has a purification catalyst (three-way catalyst) 135a that purifies harmful components in the exhaust, such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx). The purification catalyst 135a is configured to be able to store and release oxygen.

The operation of the engine 22 is controlled by an engine electronic control unit (hereinafter referred to as the "engine ECU") 24. Although not shown, the engine ECU 24 is configured as a microprocessor centered on a CPU, and in addition to the CPU, it is equipped with a ROM for storing processing programs, a RAM for temporarily storing data, a flash memory for storing and holding data, an input/output port, and a communication port.

Signals from various sensors required for controlling the operation of the engine 22 are input to the engine ECU 24 via input ports. Examples of signals input to the engine ECU 24 include the crank angle θcr from the crank position sensor 140 that detects the rotational position of the crankshaft 23 of the engine 22, and the cooling water temperature Tw from the water temperature sensor 142 that detects the temperature of the cooling water of the engine 22. Other examples include cam angles θci and θco from the cam position sensor 144 that detects the rotational position of the intake camshaft that opens and closes the intake valve 128 and the exhaust camshaft that opens and closes the exhaust valve 133. Other examples include the throttle opening TH from the throttle valve position sensor 124a that detects the position of the throttle valve 124, the intake air amount Qa from the air flow meter 123a attached upstream of the throttle valve 124 of the intake pipe 123, the intake air temperature Ta from the temperature sensor 123t attached upstream of the throttle valve 124 of the intake pipe 123, and the surge pressure Ps from the pressure sensor 125a attached to the surge tank 125. Other examples include the front air-fuel ratio AF1 from the front air-fuel ratio sensor 137 attached upstream of the purification device 135 of the exhaust pipe 134, and the rear air-fuel ratio AF2 from the rear air-fuel ratio sensor 138 attached downstream of the purification device 135 of the exhaust pipe 134.

Various control signals for controlling the operation of the engine 22 are output from the engine ECU 24 via an output port. Examples of signals output from the engine ECU 24 include a control signal to the throttle valve 124, a control signal to the port injection valve 126, a control signal to the in-cylinder injection valve 127, and a control signal to the spark plug 130.

The engine ECU 24 is connected to the HVECU 70 via a communication port. The engine ECU 24 calculates the engine speed Ne of the engine 22 based on the crank angle θcr of the engine 22 from the crank position sensor 140. The engine ECU 24 also calculates the load factor KL (the ratio of the volume of air actually taken in one cycle to the stroke volume per cycle of the engine 22) based on the intake air amount Qa from the air flow meter 123a and the engine speed Ne of the engine 22. Furthermore, the engine ECU 24 estimates the temperature Tc of the purification catalyst 135a of the purification device 135 based on the cooling water temperature Tw from the water temperature sensor 142, the engine speed Ne of the engine 22, and the load factor KL. In addition, the engine ECU 24 estimates the oxygen storage amount OS of the purification catalyst 135a of the purification device 135 based on the front air-fuel ratio AF1 from the front air-fuel ratio sensor 137 and/or the rear air-fuel ratio AF2 from the rear air-fuel ratio sensor 138 and the intake air amount Qa.

As shown in FIG. 1, the planetary gear 30 is configured as a single-pinion type planetary gear mechanism. The rotor of the motor MG1 is connected to the sun gear of the planetary gear 30. The ring gear of the planetary gear 30 is connected to a drive shaft 36 that is linked to drive wheels 39a, 39b via a differential gear 38. The carrier of the planetary gear 30 is connected to the crankshaft 23 of the engine 22 via a damper 28.

Motor MG1 is configured, for example, as a synchronous generator motor, and as described above, its rotor is connected to the sun gear of planetary gear 30. Motor MG2 is configured, for example, as a synchronous generator motor, and its rotor is connected to drive shaft 36. Inverters 41, 42 are used to drive motors MG1, MG2 and are connected to battery 50 via power line 54. Motors MG1, MG2 are rotated by motor electronic control unit (hereinafter referred to as "motor ECU") 40 controlling the switching of multiple switching elements (not shown) of inverters 41, 42.

The motor ECU 40 is configured as a microprocessor centered on a CPU (not shown), and in addition to the CPU, it is equipped with a ROM for storing processing programs, a RAM for temporarily storing data, a flash memory for storing and holding data, an input/output port, and a communication port. Signals from various sensors necessary for driving and controlling the motors MG1 and MG2 are input to the motor ECU 40 via the input port. Examples of signals input to the motor ECU 40 include the rotational positions θm1 and θm2 of the rotors of the motors MG1 and MG2 from a rotational position sensor (not shown) that detects the rotational positions of the rotors of the motors MG1 and MG2, and the phase currents Iu1, Iv1, Iu2, and Iv2 of the motors MG1 and MG2 from a current sensor (not shown) that detects the phase currents flowing through the phases of the motors MG1 and MG2. The motor ECU 40 outputs switching control signals to a plurality of switching elements (not shown) of the inverters 41 and 42 via an output port. The motor ECU 40 is connected to the HVECU 70 via a communication port. The motor ECU 40 calculates the electrical angles θe1, θe2 and rotation speeds Nm1, Nm2 of the motors MG1, MG2 based on the rotational positions θm1, θm2 of the rotors of the motors MG1, MG2 from the rotational position sensors.

The battery 50 is configured as, for example, a lithium-ion secondary battery or a nickel-hydrogen secondary battery, and as described above, is connected to the inverters 41, 42 via a power line 54. The battery 50 is managed by a battery electronic control unit (hereinafter referred to as the "battery ECU") 52.

Although not shown, the battery ECU 52 is configured as a microprocessor centered on a CPU, and in addition to the CPU, it is equipped with a ROM for storing processing programs, a RAM for temporarily storing data, a flash memory for storing and holding data, an input/output port, and a communication port. Signals from various sensors required for managing the battery 50 are input to the battery ECU 52 via the input port. Examples of signals input to the battery ECU 52 include the voltage Vb of the battery 50 from a voltage sensor (not shown) attached between the terminals of the battery 50, the current Ib of the battery 50 from a current sensor (not shown) attached to the output terminal of the battery 50, and the temperature Tb of the battery 50 from a temperature sensor (not shown) attached to the battery 50. The battery ECU 52 is connected to the HVECU 70 via a communication port. The battery ECU 52 calculates the storage ratio SOC of the battery 50 based on the integrated value of the current Ib of the battery 50 from the current sensor. The storage ratio SOC is the ratio of the capacity of the power that can be discharged from the battery 50 to the total capacity of the battery 50.

Although not shown, the HVECU 70 is configured as a microprocessor centered on a CPU, and in addition to the CPU, it is equipped with a ROM for storing processing programs, a RAM for temporarily storing data, a flash memory for storing and holding data, an input/output port, and a communication port. Signals from various sensors are input to the HVECU 70 via the input port. Examples of signals input to the HVECU 70 include an ignition signal from an ignition switch 80 and a shift position SP from a shift position sensor 82 that detects the operating position of a shift lever 81. Other examples include an accelerator opening Acc from an accelerator pedal position sensor 84 that detects the amount of depression of an accelerator pedal 83, a brake pedal position BP from a brake pedal position sensor 86 that detects the amount of depression of a brake pedal 85, a vehicle speed V from a vehicle speed sensor 88, and an outside air temperature Tout from an outside air temperature sensor 89. As described above, the HVECU 70 is connected to the engine ECU 24, the motor ECU 40, and the battery ECU 52 via the communication port.

In the hybrid vehicle 20 of the embodiment thus configured, the HVECU 70, engine ECU 24, and motor ECU 40 are controlled in a coordinated manner to run in a hybrid driving mode (HV driving mode) in which the engine 22 is rotating, or in an electric driving mode (EV driving mode) in which the engine 22 is stopped from rotating.

In addition, when the engine 22 is operated in the hybrid vehicle 20, intake air volume control, fuel injection control, ignition control, etc. are performed based on the target power Pe* of the engine 22. Intake air volume control is performed by controlling the opening of the throttle valve 124. Fuel injection control is performed by controlling the fuel injection amount from the port injection valve 126 and the in-cylinder injection valve 127 in the port injection mode, in-cylinder injection mode, and shared injection mode. Ignition control is performed by controlling the ignition timing of the spark plug 130.

Furthermore, in the hybrid vehicle 20, when a fuel cut condition is met in the HV driving mode, the engine 22 is cut off from fuel and the engine 22 is motored by the motor MG1. As a fuel cut condition, for example, a condition in which the accelerator is released when the battery 50 has a relatively large charge ratio SOC in the HV driving mode is used.

In addition, in the hybrid vehicle 20, when the execution of exhaust restriction control is required when the engine 22 is started, or when the engine 22 returns from a fuel cut (when fuel injection is resumed), the exhaust restriction control is executed. Here, the exhaust restriction control is a control that limits the displacement of the engine 22 to suppress the deterioration of emissions. In the embodiment, in the exhaust restriction control, fuel injection control is executed in the in-cylinder injection mode in consideration of the combustion stability of the engine 22. In addition, in the embodiment, as a case where the execution of the exhaust restriction control is required, a case where the execution of catalyst warm-up control is required because the temperature Tc of the purification catalyst 135a is less than the threshold value Tcref (the purification catalyst 135a is inactive) is considered, and the catalyst warm-up control is executed as the exhaust restriction control. The catalyst warm-up control is a control that controls the engine 22 by delaying the ignition timing of the engine 22 below the optimal ignition timing (MBT: Minimum advance for Best Torque) in order to promote the warm-up of the purification catalyst 135a. Hereinafter, the catalyst warm-up control after the engine 22 is started may be referred to as "first catalyst warm-up control," and the catalyst warm-up control after the engine 22 returns from a fuel cut may be referred to as "second catalyst warm-up control."

Next, the operation of the hybrid vehicle 20 of the embodiment thus configured, particularly the details of the catalyst warm-up control (first catalyst warm-up control and second catalyst warm-up control), will be described. FIG. 3 is a flowchart showing an example of a catalyst warm-up control routine executed by the engine ECU 24. This routine is executed when the execution of catalyst warm-up control is required when the engine 22 has completed starting, or when the execution of catalyst warm-up control is required when the engine 22 returns from a fuel cut.

When the catalyst warm-up control routine of FIG. 3 is executed, the engine ECU 24 first determines whether the first catalyst warm-up control or the second catalyst warm-up control is to be executed (step S100). Then, when it is determined that the first catalyst warm-up control is to be executed, the catalyst lean control in the first catalyst warm-up control is executed (steps S100 to S114). Here, the catalyst lean control is a control that controls the engine 22 so that the ignition timing of the engine 22 becomes later than the optimal ignition timing and the equivalence ratio becomes smaller than the value 1 (the air-fuel ratio becomes lean). The equivalence ratio is the theoretical air-fuel ratio/air-fuel ratio, and the target equivalence ratio is the target value of the equivalence ratio.

In the catalyst lean control in the first catalyst warm-up control, first, the first water temperature Tw1 and the first accumulated air amount Qas1 are input (step S110). Next, the target power Pe*, the target equivalence ratio φ*, and the target ignition timing IT* are set based on the input first water temperature Tw1 and the first accumulated air amount Qas1 (step S112). Then, the engine 22 is controlled using the set target power Pe*, the target equivalence ratio φ*, and the target ignition timing IT* (step S114).

Here, the cooling water temperature Tw detected by the water temperature sensor 142 at the start of the first catalyst warm-up control (e.g., when the engine 22 has finished starting) is input as the first water temperature Tw1. The first accumulated air volume Qas1 is input as a value calculated as an accumulated value of the intake air volume Qa detected by the air flow meter 123a from the start of the first catalyst warm-up control.

The target power Pe*, the target equivalence ratio φ*, and the target ignition timing IT* in the catalyst lean control of the first catalyst warm-up control are estimated, for example, by applying the first water temperature Tw1 and the first accumulated air amount Qas1 to a first map that is predefined as a relationship between the first water temperature Tw1 and the first accumulated air amount Qas1 and the target power Pe*, the target equivalence ratio φ*, and the target ignition timing IT*. The target power Pe* is set to be larger as the first water temperature Tw1 is higher and to be larger as the first accumulated air amount Qas1 is larger. The target equivalence ratio φ* is set to be smaller relative to value 1 as the first water temperature Tw1 is higher and to be smaller relative to value 1 as the first accumulated air amount Qas1 is larger. The target ignition timing IT* is set to be later as the first water temperature Tw1 is higher and to be later as the first accumulated air amount Qas1 is larger, within a range later than the optimal ignition timing. These trends take into consideration the combustion stability of the engine 22 and the purification performance of the purification catalyst 135a.

Next, it is determined whether a first transition condition is satisfied (step S116). Here, the first transition condition is a condition for transitioning from catalyst lean control to catalyst rich control described below in the first catalyst warm-up control, and for example, a condition in which the first accumulated air amount Qas1 reaches or exceeds a threshold value Qasref1 is used.

When it is determined in step S116 that the first transition condition is not satisfied, the process returns to step S110. In this manner, catalyst lean control in the first catalyst warm-up control is continued. In this manner, the processes of steps S110 to S116 are repeatedly executed, and when it is determined in step S116 that the first transition condition is satisfied, catalyst rich control in the first catalyst warm-up control is executed (steps S120 to S124). Here, catalyst rich control is control that controls the engine 22 so that the ignition timing of the engine 22 is delayed from the optimal ignition timing and the equivalence ratio is greater than the value 1 (the air-fuel ratio becomes rich).

In the catalyst rich control in the first catalyst warm-up control, first, the first water temperature Tw1 and the first accumulated air amount Qas1 are input as in the processing of step S110 (step S120). Next, the target power Pe*, the target equivalence ratio φ*, and the target ignition timing IT* are set based on the input first water temperature Tw1 and the first accumulated air amount Qas1 (step S122). Then, the engine 22 is controlled using the set target power Pe*, the target equivalence ratio φ*, and the target ignition timing IT* (step S124).

Here, the target power Pe*, the target equivalence ratio φ*, and the target ignition timing IT* in the catalyst rich control of the first catalyst warm-up control are estimated, for example, by applying the first water temperature Tw1 and the first accumulated air amount Qas1 to a second map that is predefined as a relationship between the first water temperature Tw1 and the first accumulated air amount Qas1 and the target power Pe*, the target equivalence ratio φ*, and the target ignition timing IT*. The target power Pe* is set to be larger as the first water temperature Tw1 is higher and to be larger as the first accumulated air amount Qas1 is larger. The target equivalence ratio φ* is set to be larger relative to value 1 as the first water temperature Tw1 is higher and to be larger relative to value 1 as the first accumulated air amount Qas1 is larger. The target ignition timing IT* is set to be later as the first water temperature Tw1 is higher and to be later as the first accumulated air amount Qas1 is larger, within a range later than the optimal ignition timing. These trends are based on the same reasons as the trends in the first map.

Next, it is determined whether the first end condition is satisfied (step S126). Here, the first end condition is a condition for terminating the first catalyst warm-up control (catalyst rich control in the first catalyst warm-up control), and for example, a condition in which the first injected cylinder number Nc1, which is the number of cylinders into which fuel is injected from the in-cylinder injection valve 127 in the catalyst rich control of the first catalyst warm-up control, reaches or exceeds a threshold value Ncref1, a condition in which the first accumulated air amount Qas1 reaches or exceeds a threshold value Qasref2 that is larger than the above-mentioned threshold value Qasref1, or a condition in which the temperature Tc of the purification catalyst 135a reaches or exceeds the above-mentioned threshold value Tcref, etc. are used.

If it is determined in step S126 that the first end condition is not met, the process returns to step S120. In this manner, catalyst rich control in the first catalyst warm-up control is continued. In this manner, the process of steps S120 to S126 is repeatedly executed, and if it is determined in step S126 that the first end condition is met, the first catalyst warm-up control (catalyst rich control in the first catalyst warm-up control) is terminated, and this routine is terminated.

In the embodiment, the target power Pe*, target equivalence ratio φ*, target ignition timing IT*, first transition condition, and first end condition for the catalyst lean control and catalyst rich control of the first catalyst warm-up control are set so that the first end condition is met and the first catalyst warm-up control is ended when the temperature Tc of the purification catalyst 135a reaches or exceeds the threshold value Tcref.

When it is determined in step S100 that the second catalyst warm-up control is to be performed, catalyst lean control in the second catalyst warm-up control is performed (steps S210 to S214). In catalyst lean control in the second catalyst warm-up control, the second water temperature Tw2 and the second accumulated air amount Qas2 are first input (step S210). Next, the target power Pe*, the target equivalence ratio φ*, and the target ignition timing IT* are set based on the input second water temperature Tw2 and the second accumulated air amount Qas2 (step S212). Then, the engine 22 is controlled using the set target power Pe*, the target equivalence ratio φ*, and the target ignition timing IT* (step S214).

The second water temperature Tw2 is the cooling water temperature Tw detected by the water temperature sensor 142 when the second catalyst warm-up control starts (for example, when the engine 22 returns from a fuel cut). The second accumulated air volume Qas2 is the accumulated value of the intake air volume Qa detected by the air flow meter 123a from the start of the second catalyst warm-up control.

The target power Pe*, the target equivalence ratio φ*, and the target ignition timing IT* in the catalyst lean control of the second catalyst warm-up control are estimated, for example, by applying the second water temperature Tw2 and the second accumulated air amount Qas2 to a third map that is predefined as a relationship between the second water temperature Tw2 and the second accumulated air amount Qas2 and the target power Pe*, the target equivalence ratio φ*, and the target ignition timing IT*. The target power Pe* is set to be larger as the second water temperature Tw2 is higher and to be larger as the second accumulated air amount Qas2 is larger. The target equivalence ratio φ* is set to be smaller relative to value 1 as the second water temperature Tw2 is higher and to be smaller relative to value 1 as the second accumulated air amount Qas2 is larger. The target ignition timing IT* is set to be later as the second water temperature Tw2 is higher and to be later as the second accumulated air amount Qas2 is larger, within a range later than the optimal ignition timing. These trends are based on the same reasons as the trends in the first map.

Next, it is determined whether the second transition condition is satisfied (step S216). Here, the second transition condition is a condition for transitioning from catalyst lean control to catalyst rich control in the second catalyst warm-up control, and for example, a condition in which the second accumulated air amount Qas2 reaches or exceeds the threshold value Qasref3 is used. For example, the same value as the threshold value Qasref1 described above is used as the threshold value Qasref3.

If it is determined in step S216 that the second transition condition is not satisfied, the process returns to step S210. In this manner, catalyst lean control in the second catalyst warm-up control is continued. In this manner, the process of steps S210 to S216 is repeatedly executed, and if it is determined in step S216 that the second transition condition is satisfied, catalyst rich control in the second catalyst warm-up control is executed (steps S220 to S224).

In the catalyst rich control in the second catalyst warm-up control, first, the second water temperature Tw2 and the second accumulated air amount Qas2 are input as in the processing of step S210 (step S220). Next, the target power Pe*, the target equivalence ratio φ*, and the target ignition timing IT* are set based on the input second water temperature Tw2 and the second accumulated air amount Qas2 (step S222). Then, the engine 22 is controlled using the set target power Pe*, the target equivalence ratio φ*, and the target ignition timing IT* (step S224).

Here, the target power Pe*, the target equivalence ratio φ*, and the target ignition timing IT* in the catalyst rich control of the second catalyst warm-up control are estimated, for example, by applying the second water temperature Tw2 and the second accumulated air amount Qas2 to a fourth map that is predefined as a relationship between the second water temperature Tw2 and the second accumulated air amount Qas2 and the target power Pe*, the target equivalence ratio φ*, and the target ignition timing IT*. The target power Pe* is set to be larger as the second water temperature Tw2 is higher and to be larger as the second accumulated air amount Qas2 is larger. The target equivalence ratio φ* is set to be larger relative to value 1 as the second water temperature Tw2 is higher and to be larger relative to value 1 as the second accumulated air amount Qas2 is larger. The target ignition timing IT* is set to be later as the second water temperature Tw2 is higher and to be later as the second accumulated air amount Qas2 is larger, within a range later than the optimal ignition timing. These trends are based on the same reasons as the trends in the first map.

Next, it is determined whether the second end condition is satisfied (step S226). Here, the second end condition is a condition for terminating the second catalyst warm-up control (catalyst rich control in the second catalyst warm-up control), and for example, a condition in which the second injected cylinder number Nc2, which is the number of cylinders into which fuel is injected from the in-cylinder injection valve 127 in the catalyst rich control of the second catalyst warm-up control, reaches or exceeds the threshold value Ncref2, a condition in which the second accumulated air amount Qas2 reaches or exceeds the threshold value Qasref4, which is greater than the above-mentioned threshold value Qasref3, or a condition in which the temperature Tc of the purification catalyst 135a reaches or exceeds the above-mentioned threshold value Tcref, etc. are used. For example, the same value as the above-mentioned threshold value Ncref1 is used as the threshold value Ncref2. For example, the same value as the above-mentioned threshold value Qasref2 is used as the threshold value Qasref4.

If it is determined in step S226 that the second end condition is not met, the process returns to step S220. In this manner, catalyst rich control in the second catalyst warm-up control is continued. In this manner, the process of steps S220 to S226 is repeatedly executed, and if it is determined in step S226 that the second end condition is met, the second catalyst warm-up control (catalyst rich control in the second catalyst warm-up control) is terminated, and this routine is terminated.

In the embodiment, the target power Pe*, target equivalence ratio φ*, target ignition timing IT*, second transition condition, and second end condition are set in the catalyst lean control and catalyst rich control of the second catalyst warm-up control so that the second end condition is met and the second catalyst warm-up control is ended when the temperature Tc of the purification catalyst 135a reaches or exceeds the threshold value Tcref.

In this manner, in the embodiment, in the first catalyst warm-up control, catalyst lean control and catalyst rich control are executed based on the first water temperature Tw1 and the first accumulated air amount Qas1, and in the second catalyst warm-up control, catalyst lean control and catalyst rich control are executed based on the second water temperature Tw2 and the second accumulated air amount Qas2. Here, consider a case where, after starting the engine 22, catalyst warm-up control (first catalyst warm-up control) is executed because the purification catalyst 135a is at a low temperature, fuel cut is then executed, and after returning from the fuel cut, catalyst warm-up control (second catalyst warm-up control) is executed again due to a decrease in the temperature of the purification catalyst 135a during the fuel cut. At this time, a relatively large deviation may occur between the first water temperature Tw1 and the second water temperature Tw2 due to the operating state of the engine 22 before the fuel cut and the fuel cut time. Therefore, if the catalyst lean control and catalyst rich control are executed based on the first water temperature Tw1 and the first accumulated air amount Qas1 in the second catalyst warm-up control, the state of the engine 22 at that time is not appropriately reflected, so the target power Pe*, the target equivalence ratio φ*, and the target ignition timing IT* cannot be appropriately set, and the engine 22 may not be appropriately controlled. In contrast, in the embodiment, the catalyst lean control and catalyst rich control are executed based on the second water temperature Tw2 and the second accumulated air amount Qas2 in the second catalyst warm-up control, so that the target power Pe*, the target equivalence ratio φ*, and the target ignition timing IT* can be set to more appropriately reflect the state of the engine 22 at that time, and the engine 22 can be controlled more appropriately. As a result, the second catalyst warm-up control can be executed more appropriately.

4 is an explanatory diagram showing an example of the rotation speed Ne of the engine 22, whether or not fuel cut is performed, the temperature Tc of the purification catalyst 135a, whether or not catalyst warm-up control is performed, the cooling water temperature Tw, the first accumulated air amount Qas1, the second accumulated air amount Qas2, the target power Pe*, the target equivalence ratio φ*, and the target ignition timing IT*. As shown in the figure, when the start of the engine 22 is completed (time t11), if the temperature Tc of the purification catalyst 135a is less than the threshold value Tcref, in the first catalyst warm-up control, the target power Pe*, the target equivalence ratio φ*, and the target ignition timing IT* are set based on the cooling water temperature Tw (first water temperature Tw1) and the first accumulated air amount Qas1 at the start of the first catalyst warm-up control, and the catalyst lean control and the catalyst rich control are performed. Then, when the first end condition is established near the temperature Tc of the purification catalyst 135a reaching the threshold value Tcref or higher (time t12), the first catalyst warm-up control is ended. After that, the engine 22 is cut off from fuel (time t13 to t14), and when the engine 22 returns from the fuel cut (time t14), if the temperature Tc of the purification catalyst 135a is less than the threshold value Tcref, the second catalyst warm-up control sets the target power Pe*, the target equivalence ratio φ*, and the target ignition timing IT* based on the cooling water temperature Tw (second water temperature Tw2) and the second integrated air amount Qas2 at the start of the second catalyst warm-up control, and executes the catalyst lean control and the catalyst rich control. Then, when the second end condition is satisfied near the time when the temperature Tc of the purification catalyst 135a reaches the threshold value Tcref or more (time t15), the second catalyst warm-up control is ended. As a result, compared to the first catalyst warm-up control and the second catalyst warm-up control in which catalyst lean control and catalyst rich control are performed based on the first water temperature Tw1 and the first accumulated air amount Qas1 in either the first catalyst warm-up control or the second catalyst warm-up control, the second catalyst warm-up control can control the engine 22 by more appropriately reflecting the state of the engine 22 at that time, and therefore the engine 22 can be more appropriately controlled. As a result, the second catalyst warm-up control can be more appropriately performed.

In the engine device 21 mounted on the hybrid vehicle 20 of the embodiment described above, in the first catalyst warm-up control (catalyst warm-up control after the engine 22 is started), the engine 22 is controlled based on the first water temperature Tw1 and the first accumulated air amount Qas1 (catalyst lean control and catalyst rich control are executed), and in the second catalyst warm-up control (catalyst warm-up control after the engine 22 returns from a fuel cut), the engine 22 is controlled based on the second water temperature Tw2 and the second accumulated air amount Qas2. This allows the second catalyst warm-up control to be executed more appropriately.

In the engine device 21 mounted on the hybrid vehicle 20 of the embodiment, the first catalyst warm-up control controls the engine 22 based on the first water temperature Tw1 and the first accumulated air amount Qas1, and the second catalyst warm-up control controls the engine 22 based on the second water temperature Tw2 and the second accumulated air amount Qas2. However, the first catalyst warm-up control may control the engine 22 based on the first water temperature Tw1 without considering the first accumulated air amount Qas1, and the second catalyst warm-up control may control the engine 22 based on the second water temperature Tw2 without considering the second accumulated air amount Qas2.

In the engine device 21 mounted on the hybrid vehicle 20 of the embodiment, in the first catalyst warm-up control, the target power Pe*, the target equivalence ratio φ*, and the target ignition timing IT* are set based on the first water temperature Tw1 and the first accumulated air amount Qas1, and in the second catalyst warm-up control, the target power Pe*, the target equivalence ratio φ*, and the target ignition timing IT* are set based on the second water temperature Tw2 and the second accumulated air amount Qas2. However, in the first catalyst warm-up control, one of the target power Pe*, the target equivalence ratio φ*, and the target ignition timing IT* may be set based on the first water temperature Tw1 and the first accumulated air amount Qas1, and the remaining two may be set based on this one. In addition, in the second catalyst warm-up control, one of the target power Pe*, the target equivalence ratio φ*, and the target ignition timing IT* may be set based on the second water temperature Tw2 and the second accumulated air amount Qas2, and the remaining two may be set based on this one.

In the engine device 21 mounted on the hybrid vehicle 20 of the embodiment, in the first catalyst warm-up control, the target power Pe*, the target equivalence ratio φ*, and the target ignition timing IT* are set based on the first water temperature Tw1 and the first accumulated air amount Qas1, and in the second catalyst warm-up control, the target power Pe*, the target equivalence ratio φ*, and the target ignition timing IT* are set based on the second water temperature Tw2 and the second accumulated air amount Qas2. However, for the first catalyst warm-up control, it is sufficient that at least one of the target power Pe*, the target equivalence ratio φ*, and the target ignition timing IT* is set based on the first water temperature Tw1 and the first accumulated air amount Qas1. Also, for the second catalyst warm-up control, it is sufficient that at least one of the target power Pe*, the target equivalence ratio φ*, and the target ignition timing IT* is set based on the second water temperature Tw2 and the second accumulated air amount Qas2.

In the engine device 21 mounted on the hybrid vehicle 20 of the embodiment, in the first catalyst warm-up control, the target power Pe*, the target equivalence ratio φ*, and the target ignition timing IT* are set based on the first water temperature Tw1 and the first accumulated air amount Qas1, and in the second catalyst warm-up control, the target power Pe*, the target equivalence ratio φ*, and the target ignition timing IT* are set based on the second water temperature Tw2 and the second accumulated air amount Qas2. However, in the first catalyst warm-up control, in addition to at least one of the target power Pe*, the target equivalence ratio φ*, and the target ignition timing IT*, at least one of the injection mode in the fuel injection control (either port injection mode, in-cylinder injection mode, or shared injection mode), injection timing, the number of injections (in the case of injection in multiple divided injections), the fuel pressure supplied to the in-cylinder injection valve 127, and the opening and closing timing of the intake valve 128 and the exhaust valve 133 (in the case of the engine 22 being equipped with a variable valve timing device that can change the opening and closing timing of the intake valve 128 and the exhaust valve 133) may also be set based on the first water temperature Tw1 and the first accumulated air amount Qas1. In addition, in the second catalyst warm-up control, in addition to at least one of the target power Pe*, the target equivalence ratio φ*, and the target ignition timing IT*, at least one of the injection mode, injection timing, number of injections, fuel pressure supplied to the in-cylinder injection valve 127, and the opening and closing timing of the intake valve 128 and the exhaust valve 133 (if a variable valve timing device is provided) in the fuel injection control may be set based on the second water temperature Tw2 and the second accumulated air amount Qas2.

In the engine device 21 mounted on the hybrid vehicle 20 of the embodiment, fixed values are used as the thresholds Ncref1 and Qasref2 of the first termination condition, and as the thresholds Ncref2 and Qasref4 of the second termination condition. However, the thresholds Ncref1 and Qasref2 may be values based on the first water temperature Tw1, for example values that decrease as the first water temperature Tw1 increases. Furthermore, the thresholds Ncref2 and Qasref4 may be values based on the second water temperature Tw2, for example values that decrease as the second water temperature Tw2 increases.

In the engine device 21 mounted on the hybrid vehicle 20 of the embodiment, catalyst warm-up control (first catalyst warm-up control and second catalyst warm-up control) executes catalyst lean control and catalyst rich control in this order. However, the catalyst warm-up control is not limited to this as long as it executes control to control the engine 22 by delaying the ignition timing of the engine 22 from the optimal ignition timing. For example, the catalyst warm-up control may execute different controls in that the target equivalence ratio φ* is set to a value of 1 for the catalyst lean control and the catalyst rich control.

In the engine device 21 mounted on the hybrid vehicle 20 of the embodiment, the case where the execution of the exhaust restriction control is required is considered as a case where the execution of the catalyst warm-up control is required because the temperature Tc of the purification catalyst 135a is less than the threshold value Tcref, and the catalyst warm-up control is executed as the exhaust restriction control. However, when the execution of the exhaust restriction control is required for a reason other than the case where the execution of the catalyst warm-up control is required (for example, the first water temperature Tw1 is extremely low or extremely high), a control different from the catalyst warm-up control may be executed as the exhaust restriction control. In this case, for example, a control different from the catalyst lean control and the catalyst rich control may be executed as the exhaust restriction control in that the optimal ignition timing is set to the target ignition timing IT*.

In the embodiment, the engine device 21 mounted on the hybrid vehicle 20 uses a four-cylinder engine 22. However, a six-cylinder, eight-cylinder, or twelve-cylinder engine may also be used.

In the embodiment, the hybrid vehicle 20 includes an engine ECU 24, a motor ECU 40, a battery ECU 52, and an HVECU 70. However, at least two of these may be configured as a single electronic control unit.

In the embodiment, the engine device is mounted on a hybrid vehicle 20 having an engine 22, a planetary gear 30, and motors MG1 and MG2. However, the engine device may be mounted on a so-called one-motor hybrid vehicle having an engine and one motor. The engine device may also be mounted on a vehicle that does not have a motor for running and runs using only power from the engine. Furthermore, the engine device may be mounted on stationary equipment such as construction equipment.

The following describes the relationship between the main elements of the embodiment and the main elements of the invention described in the section on means for solving the problem. In the embodiment, the engine 22 corresponds to the "engine", the purification catalyst 135a corresponds to the "purification catalyst", and the engine ECU 24 corresponds to the "control device".

The correspondence between the main elements of the Examples and the main elements of the invention described in the Means for Solving the Problem column does not limit the elements of the invention described in the Means for Solving the Problem column, since the Examples are examples for specifically explaining the form for implementing the invention described in the Means for Solving the Problem column. In other words, the interpretation of the invention described in the Means for Solving the Problem column should be based on the description in that column, and the Examples are merely a specific example of the invention described in the Means for Solving the Problem column.

The above describes the form for carrying out the present invention using examples, but the present invention is not limited to these examples in any way, and it goes without saying that the present invention can be carried out in various forms without departing from the spirit of the present invention.

The present invention can be used in the engine equipment manufacturing industry, etc.

20 Hybrid vehicle, 21 Engine device, 22 Engine, 23 Crankshaft, 24 Engine ECU, 28 Damper, 30 Planetary gear, 36 Drive shaft, 38 Differential gear, 39a, 39b Drive wheels, 40 Motor ECU, 41, 42 Inverter, 50 Battery, 52 Battery ECU, 54 Power line, 70 HV ECU, 80 Ignition switch, 81 Shift lever, 82 Shift position sensor, 83 Accelerator pedal, 84 Accelerator pedal position sensor, 85 Brake pedal, 86 Brake pedal position sensor, 88 Vehicle speed sensor, 89 Outside air temperature sensor, 122 Air cleaner, 123 Intake pipe, 123a Air flow meter, 123t Temperature sensor, 124 Throttle valve, 124a Throttle valve position sensor, 125 Surge tank, 125a Pressure sensor, 126 port injection valve, 127 in-cylinder injection valve, 128 intake valve, 129 combustion chamber, 130 spark plug, 132 piston, 133 exhaust valve, 134 exhaust pipe, 135 purification device, 135a purification catalyst, 137 front air-fuel ratio sensor, 138 rear air-fuel ratio sensor, 140 crank position sensor, 142 water temperature sensor, 144 cam position sensor, MG1, MG2 motor.

Claims (1)

An engine device including an engine, a purification catalyst that purifies exhaust gas from the engine, and a control device that controls the engine,
The control device includes:
When executing a first exhaust restriction control which is an exhaust restriction control for restricting an exhaust amount of the engine after a start of the engine, the engine is controlled based on a first temperature which is a temperature of the engine at the start of the first exhaust restriction control and a first integrated air amount which is an integrated value of an intake air amount from the start of the first exhaust restriction control ,
When executing a second exhaust restriction control which is the exhaust restriction control after the engine returns from a fuel cut, the engine is controlled based on a second temperature which is the temperature of the engine at the start of the second exhaust restriction control and a second integrated air amount which is an integrated value of the intake air amount from the start of the second exhaust restriction control .
Engine equipment.

Images