Patent Application
20230079934
The present disclosure relates to a control device of an internal combustion engine.
Conventionally, an invention related to a waste heat control device for an engine that controls a waste heat amount of the engine on the basis of a heat use request has been known (see PTL 1 below). The engine waste heat control device described in PTL 1 is applied to a waste heat reuse system that recovers and reuses waste heat of an engine, and controls the amount of waste heat of the engine on the basis of a required heat amount by a heat use request. The conventional waste heat control device includes an overlap amount control unit, an ignition control unit, and a waste heat control unit (Abstract, paragraph 0008, claim 1, and the like in the PTL 1).
An overlap amount control unit controls an overlap amount between an opening period of an intake valve and an opening period of an exhaust valve of the engine on the basis of an engine operation state. The ignition control unit controls the ignition timing of the engine at the maximum efficiency timing at which the maximum fuel consumption is achieved in each engine operation state. The waste heat control unit executes overlap increase control for changing the overlap amount to an increase side and ignition advance control for changing the ignition timing to an advance side from the highest efficiency timing corresponding to the overlap amount after the change to the increase side when the required heat amount is not satisfied.
As in the above configuration, the conventional waste heat control device changes the overlap amount to the increase side when the required heat amount cannot be satisfied, and changes the ignition timing to the advance side from the highest efficiency timing (MBT or the vicinity thereof) corresponding to the overlap amount after the change to the increase side. As a result, it is possible to perform waste heat control in accordance with the heat use request while suppressing fuel consumption deterioration as much as possible (paragraph 0009, etc. in the PTL 1).
PTL 1: JP 2011-074800 A
The conventional waste heat control device can obtain a certain effect when mainly recovering the waste heat of the engine by the coolant. However, the conventional waste heat control device has a problem that the operation frequency of the engine is low, and it is not possible to cope with a situation in which both the temperature of the catalyst included in the exhaust system of the engine and the temperature of the coolant are low.
The present disclosure provides a control device of an internal combustion engine capable of increasing the temperature of a catalyst and the temperature of coolant more efficient1y than the conventional waste heat control device as described above.
One aspect of the present disclosure is a control device that acquires a coolant temperature and a catalyst temperature of an exhaust system and controls an ignition timing of an internal combustion engine. The control device executes: coolant heating control for increasing an energy distribution from the internal combustion engine to a coolant when the coolant temperature is equal to or lower than a first threshold; and catalyst heating control for increasing an energy distribution from the internal combustion engine to the exhaust gas when the catalyst temperature is equal to or lower than a second threshold.
According to the above aspect of the present disclosure, it is possible to provide a control device of an internal combustion engine capable of increasing the temperature of a catalyst and the temperature of coolant more efficient1y than a conventional waste heat control device.
Hereinafter, embodiments of a control device of an internal combustion engine according to the present disclosure will be described with reference to the drawings.
The vehicle includes, for example, the engine 1, a generator 2, inverters 3A and 3B, a power storage device 4, a motor 5, a vehicle control device 6, an accelerator pedal 7, and the control device 10 of the internal combustion engine. The vehicle includes, for example, a crank angle sensor S1, an accelerator opening sensor S2, and a battery voltage sensor S3. The engine 1 is, for example, a spark ignition engine, and is, for example, a four-cylinder gasoline engine. The generator 2 is connected to a crankshaft la of the engine 1 and generates electric power by rotation of the crankshaft la.
For example, the power storage device 4 is connected to a generator via the inverter 3A, and is connected to the motor 5 via the inverter 3B. The power storage device 4 includes, for example, a plurality of secondary batteries, and is charged with generated power supplied from the generator 2 via the inverter 3A or regenerative power supplied from the motor 5 via the inverter 3B. The power storage device 4 supplies electric power to the motor 5 via the inverter 3B to drive the motor 5. The motor 5 is driven by electric power supplied from the power storage device 4 via the inverter 3B, and rotates wheels (not illustrated) to drive the vehicle.
The vehicle control device 6 is connected to the crank angle sensor S1, the accelerator opening sensor S2, the battery voltage sensor S3, and the control device 10 of the internal combustion engine so as to be able to communicate information. The crank angle sensor S1 detects a rotation angle of the crankshaft la of the engine 1. The accelerator opening sensor S2 detects a depression amount of the accelerator pedal 7, that is, an accelerator opening degree. The battery voltage sensor S3 measures an internal voltage of the power storage device 4. The vehicle control device 6 receives signals of a detection result and a measurement result from the sensors S1, S2, and S3.
The vehicle control device 6 calculates required torque based on the operation of the driver of the vehicle on the basis of the detection result of the accelerator opening degree input from the accelerator opening sensor S2. That is, the accelerator opening sensor S2 can be used as required torque sensor that detects required torque for the engine 1 or the motor 5. The vehicle control device 6 calculates a state of charge or a charged remaining power amount of the power storage device 4 on the basis of the detection result of the internal voltage of the power storage device 4 input from the battery voltage sensor S3. The vehicle control device 6 calculates the rotation speed of the engine 1 on the basis of the detection result of the rotation angle of the crankshaft la input from the crank angle sensor S1.
Further, the vehicle control device 6 calculates an optimum operation amount of each device such as the required output of the engine 1 and the required output of the power storage device 4 on the basis of the required torque based on the input from each of the sensors S1, S2, and S3 and the operation state of the vehicle. The vehicle control device 6 outputs a control signal including the calculated required output of the engine 1 to the control device 10 of the internal combustion engine. The control device 10 of the internal combustion engine controls the engine 1 on the basis of the control signal including the required output of the engine 1 input from the vehicle control device 6.
In addition to the crankshaft la and the crank angle sensor S1 of
For example, the intake pipe 1b circulates air flowing into each cylinder 1d of the engine 1. The air flow sensor S4 is provided, for example, at an appropriate position of the intake pipe 1b, measures the flow rate of air flowing through the intake pipe 1b, and outputs the measurement result to the control device 10. The electronically controlled thrott1e 1c is controlled by the control device 10, for example, and adjusts the flow rate of air flowing into each cylinder 1d. The intake temperature sensor S5 measures, for example, the temperature of air flowing through the intake pipe 1b, and outputs the measurement result to the control device 10.
The injector 1e is, for example, a fuel injection device or an in-cylinder direct injection injector that is provided in each cylinder 1d (#1 to #4) and injects fuel into a combustion chamber of each cylinder 1d. The ignition coil if generates, for example, a high voltage for discharging with an ignition plug provided in each cylinder 1d. The coolant temperature sensor S6 is provided, for example, at an appropriate position of the cylinder head of the engine 1, measures the coolant temperature of the engine 1, and outputs the measurement result to the control device 10. The knock sensor S7 is provided, for example, in a cylinder block of the engine 1, detects vibration of the engine 1, and outputs the detection result to the control device 10.
For example, the exhaust pipe 1g circulates exhaust gas discharged from each cylinder of the engine 1. The three-way catalyst 1h is provided at an appropriate position of the exhaust pipe 1g, for example, and purifies the exhaust gas flowing through the exhaust pipe lg. The air-fuel ratio sensor S8 is provided, for example, on the upstream side of the three-way catalyst 1h in the exhaust pipe 1g in the exhaust flow, measures the air-fuel ratio of the exhaust, and outputs the measurement result to the control device 10. The exhaust gas temperature sensor S9 is provided, for example, on the upstream side of the three-way catalyst 1h in the exhaust pipe 1g in the exhaust flow, measures the exhaust temperature, and outputs the measurement result to the control device 10.
The control device 10 of the internal combustion engine of the present embodiment is, for example, an electronic control device (ECU) including a processing device such as a CPU, a storage device such as a memory, a signal input/output unit, and the like. The control device 10 receives the measurement results from, for example, the crank angle sensor S1, the air flow sensor S4, the intake temperature sensor S5, the coolant temperature sensor S6, the knock sensor S7, the air-fuel ratio sensor S8, and the exhaust gas temperature sensor S9 described above. The control device 10 receives the measurement result of the accelerator opening sensor S2 via the above-described vehicle control device 6, for example.
In the control device 10, the required torque of the engine 1 calculated by the vehicle control device 6 on the basis of the measurement result of the accelerator opening sensor S2 is input from the vehicle control device 6. In the control device 10, the rotation speed of the engine 1 calculated by the vehicle control device 6 on the basis of the measurement result of the crank angle sensor S1 is input from the vehicle control device 6. The required torque and the rotation speed of the engine 1 can also be calculated by the control device 10 on the basis of the measurement result of the accelerator opening sensor S2 and the measurement result of the crank angle sensor S1, respectively.
The control device 10 calculates the operation state of the engine 1 on the basis of, for example, the information input from each of the above-described sensors. The control device 10 calculates main control parameters of the engine 1 including an ignition timing, a thrott1e opening degree, a fuel injection amount, and the like of the engine 1.
The fuel injection amount calculated by the control device 10 is converted into, for example, a valve opening pulse signal, and is output from the control device 10 to the injector le. The ignition timing calculated by the control device 10 is converted into, for example, an ignition signal and output from the control device 10 to the ignition coil lf. The thrott1e opening degree calculated by the control device 10 is converted into a thrott1e drive signal and output from the control device 10 to the electronically controlled thrott1e 1c.
The electronically controlled thrott1e 1c allows air to pass at a thrott1e opening degree according to the thrott1e drive signal input from the control device 10. The air that has passed through the electronically controlled thrott1e 1c flows through the intake pipe 1b and flows into the combustion chamber of each cylinder 1d via an intake valve (not illustrated). The injector 1e injects fuel into the combustion chamber of each cylinder 1d according to the valve opening pulse signal input from the control device 10. As a result, an air-fuel mixture is generated in the combustion chamber of each cylinder 1d.
The ignition coil if generates a high voltage for discharging by the ignition plug according to the ignition signal input from the control device 10. As a result, the air-fuel mixture is combusted in the combustion chamber of each cylinder 1d, the piston in each cylinder 1d (not illustrated) is pushed down, a driving force is generated in the engine 1, and the crankshaft la rotates. The exhaust gas discharged from the combustion chamber of each cylinder 1d after the combustion of the air-fuel mixture flows through the exhaust pipe 1g, is purified by the three-way catalyst 1h, and is discharged to the outside.
For example, required torque τ_req and a rotation speed R_eng of the engine 1 calculated by the vehicle control device 6 and output from the vehicle control device 6 are input to the input circuit 11. In the input circuit 11, for example, a thrott1e opening degree P_thr is input from the electronically controlled thrott1e 1c, an exhaust temperature T_exh is input from the exhaust gas temperature sensor S9, and a coolant temperature T_cw is input from the coolant temperature sensor S6.
Although not illustrated in
The RAM 13 acquires information output from the input circuit 11 via the input/output port 12 and temporarily holds the information. The ROM 14 stores various control programs and data.
The CPU 15 executes various control programs stored in the ROM 14 to execute various arithmetic processing using the information stored in the RAM 13. Through the various types of arithmetic processing, the CPU 15 calculates various control parameters including the operation amounts of the various actuators of the vehicle, and causes the RAM 13 to hold the control parameters.
Further, the CPU 15 outputs various control parameters held in the RAM 13 to various drive circuits including the ignition control unit 16 and the thrott1e control unit 17 via the output port of the input/output port 12. The control device 10 may include a drive circuit other than the ignition control unit 16 and the thrott1e control unit 17. These drive circuits may be installed outside the control device 10.
The ignition control unit 16 outputs an ignition signal S_ign to the ignition coil if on the basis of the control parameter input via the output port of the input/output port 12. The thrott1e control unit 17 outputs a control signal S_thr of the thrott1e opening degree to the electronically controlled thrott1e 1c on the basis of the control parameter input via the output port of the input/output port 12.
The CPU 15 detects the occurrence of knocking by executing arithmetic processing using the detection result of the vibration of the engine 1 input from the knock sensor S7 to the input circuit 11 and held in the RAM 13 via the input/output port 12. The CPU 15 estimates the temperature of the three-way catalyst 1h in the exhaust system, that is, a catalyst temperature T_cat by executing arithmetic processing using the exhaust temperature T_exh input from the exhaust gas temperature sensor S9 to the input circuit 11 and held in the RAM 13 via the input/output port 12.
The function F1 of calculating the ignition timing correction amount Δθ uses, for example, the required torque τ_req and the rotational speed R_eng of the engine 1, the coolant temperature T_cw, the catalyst temperature T_cat, and an ignition timing θ as inputs. The function F1 calculates the ignition timing correction amount Δθ on the basis of these inputs.
The function F2 of correcting the ignition timing uses, for example, the ignition timing θ and the ignition timing correction amount Δθ as inputs, and calculates a corrected ignition timing θ.
In
Here, advancing the ignition timing θ of the engine 1 is synonymous with decreasing the crank angle at the ignition timing θ. Retarding the ignition timing θ of the engine 1 is synonymous with increasing the crank angle at the ignition timing θ. Therefore, hereinafter, the correction of the ignition timing θ in which the ignition timing correction amount Δθ becomes negative is referred to as advance correction, and the correction of the ignition timing θ in which the ignition timing correction amount Δθ becomes positive is referred to as retardation correction.
The energy distribution η_i to the power of the engine 1 becomes maximum at an optimum ignition timing θo, and decreases when the ignition timing θ is corrected to advance or retard from the optimum ignition timing θo. The energy distribution η_cw from the engine 1 to the coolant increases as the ignition timing correction amount Δθ of the advance correction increases. The energy distribution η_exh from the engine 1 to the exhaust gas increases as the correction amount of the retardation correction increases. That is, in the engine 1, the energy distributions η_i, η_cw, and η_exh to the power, the coolant, and the exhaust gas change depending on the ignition timing θ.
In
As illustrated in
As a result, in the graph of the ignition timing θ and the graph of a torque target value τ of
On the other hand, when the engine 1 is started at time t0, the control device 10 of the present embodiment starts the processing flow illustrated in
In the process P2, the control device 10 executes coolant heating control for increasing the energy distribution η_cw from the engine 1, which is an internal combustion engine, to the coolant. For example, the control device 10 executes the advance control for advancing the ignition timing θ in the coolant heating control. More specifically, the control device 10 sets the ignition timing correction amount Δθ to a negative value by the function F1, for example. Here, for the setting of the ignition timing correction amount Δθ, for example, the following setting C1 and setting C2 can be selected.
In the setting C1, for example, the ignition timing correction amount Δθ is set to a predetermined negative fixed value. In the setting C2, for example, the ignition timing correction amount Δθ is set so as to have a correlation with a coolant temperature deviation ΔT_cw. Here, the coolant temperature deviation ΔT_cw is, for example, a difference between the coolant temperature T_cw and the first threshold Tl which is a predetermined temperature threshold. More specifically, in the setting C2, the ignition timing correction amount Δθ can be set as, for example, the following Expression (1) or (2).
Δθ=A×(T1−T_cw)+Δθas(T_cw<T1) (1)
Δθ=Δθas(T_cw≥T1) (2)
In the above Expressions (1) and (2), A is a positive constant, and Δθas is a reference advance correction amount. In this setting C2, by setting the ignition timing correction amount Δθ as in the above (1) and (2), a negative correlation can be given between the ignition timing correction amount Δθ and the coolant temperature deviation ΔT_cw. In other words, in the setting C2, the ignition timing correction amount Δθ (absolute value), which is the correction amount of the advance correction, increases as the coolant temperature deviation ΔT_cw increases.
In the advance correction, the ignition timing correction amount Δθ becomes a negative value. Therefore, increasing the ignition timing correction amount Δθ as the advance correction amount is synonymous with increasing the absolute value of the ignition timing correction amount Δθ. The reference advance correction amount Δθas can be determined on the basis of, for example, a map created by performing an experiment or simulation using the engine 1 in advance and acquiring parameters such as the coolant temperature T_cw and the operating conditions. The reference advance correction amount Deas can be set to a negative value.
As described above, the function F1 of calculating the ignition timing correction amount Δθ of the control device 10 executes the advance control for advancing the ignition timing in the coolant heating control executed in the process P2. In the advance control executed in the process P2, when the setting C2 is selected, the function F1 increases the ignition timing correction amount Δθ as the advance correction amount for advancing the ignition timing e as the difference between the first threshold T1 and the coolant temperature T_cw increases.
As described above, in the process P2 illustrated in
The corrected ignition timing θ calculated by the function F2 of correcting the ignition timing of the control device 10 is converted into the ignition signal S_ign by the ignition control unit 16 illustrated in
As a result, in the setting C1 in which the ignition timing correction amount Δθ is set to a predetermined negative fixed value, as indicated by a dotted line in the graph of the ignition timing θ in
In the setting C2, the ignition timing correction amount Δθ as the advance correction amount is increased as the coolant temperature deviation ΔT_cw is increased. As a result, as indicated by a chain line in the graph of the ignition timing θ in
The coolant temperature T_cw increases by the setting C1 of the advance control of the present embodiment indicated by a dotted line in the graph of the coolant temperature T_cw in
In the process P3, the function F1 sets the ignition timing correction amount Δθ to zero, and ends the processing flow illustrated in
As a result, as indicated by a dotted line in the graph of the ignition timing θ in
As a result, as illustrated in
The horizontal axis and the vertical axis of each graph in
As illustrated in
As a result, in the graph of the ignition timing θ and the graph of the torque target value i in
On the other hand, when the engine 1 is started at time t0, the control device 10 of the present embodiment starts the processing flow illustrated in
In the process P5, the control device 10 executes catalyst heating control for increasing the energy distribution η_exh from the engine 1, which is an internal combustion engine, to the exhaust gas. For example, the control device 10 executes retardation control for delaying the ignition timing θ in the catalyst heating control. More specifically, the control device 10 sets the ignition timing correction amount Δθ to a positive value by the function F1, for example. Here, for the setting of the ignition timing correction amount Δθ, for example, the following setting C3 and setting C4 can be selected.
In the setting C3, for example, the ignition timing correction amount Δθ is set to a predetermined positive fixed value. In the setting C4, for example, the ignition timing correction amount Δθ is set to have correlation with a catalyst temperature deviation ΔT_cat. Here, the catalyst temperature deviation ΔT_cat is, for example, a difference between the catalyst temperature T_cat and the second threshold T2 which is a predetermined temperature threshold. More specifically, in the setting C4, the ignition timing correction amount Δθ can be set as, for example, the following Expression (3) or (4).
Δθ=B×(T2−T_cat)+Δθds(T_cat<T2) (3)
Δθ=Δθds(T_cat>T2) (4)
In the above Expressions (3) and (4), B is a positive constant, and Aeds is a reference retardation correction amount. In this setting C4, by setting the ignition timing correction amount Δθ as in the above (3) and (4), a positive correlation can be given between the ignition timing correction amount Δθ and the catalyst temperature deviation ΔT_cat. In other words, in the setting C2, the ignition timing correction amount Δθ, which is the correction amount of the retardation correction, increases as the catalyst temperature deviation ΔT_cat increases.
In the retardation correction, the ignition timing correction amount Δθ is a positive value. Therefore, increasing the ignition timing correction amount Δθ as the retardation correction amount is synonymous with increasing the ignition timing correction amount Δθ. The reference retardation correction amount Δθds can be determined on the basis of a map created by, for example, acquiring parameters such as the catalyst temperature T_cat and the operation condition by performing an experiment or simulation using the engine 1 in advance. The reference retardation correction amount Δθds can be set to a positive value.
As described above, the function F1 of calculating the ignition timing correction amount Δθ of the control device 10 executes the retardation control for delaying the ignition timing in the catalyst heating control executed in the process P5. In the retardation control executed in the process P5, when the setting C4 is selected, the function F1 increases the ignition timing correction amount Δθ as a retardation correction amount for delaying the ignition timing θ as the difference between the second threshold T2 and the catalyst temperature T_cat increases.
As described above, in the process P5 illustrated in
The corrected ignition timing θ′ calculated by the function F2 of correcting the ignition timing of the control device 10 is converted into the ignition signal S_ign by the ignition control unit 16 illustrated in
As a result, in the setting C3 in which the ignition timing correction amount Δθ is set to a predetermined positive fixed value, as indicated by a dotted line in the graph of the ignition timing θ in
In the setting C4, the ignition timing correction amount Δθ as the retardation correction amount is increased as the catalyst temperature deviation ΔT_cat is increased. As a result, as indicated by a chain line in the graph of the ignition timing θ in
The catalyst temperature T_cat increases by the setting C3 of the retardation control of the present embodiment indicated by a dotted line in the graph of the catalyst temperature T_cat of
In the process P6, the function F1 sets the ignition timing correction amount Δθ to zero, and ends the processing flow illustrated in
As a result, as indicated by a dotted line in the graph of the ignition timing θ in
As a result, as illustrated in
Next, the function F2 executes a process P8 for determining whether the ignition timing correction amount Δθ is negative. In this process P8, when determining that the ignition timing correction amount Δθ is negative (YES), the function F2 executes a process P9 for determining whether the ignition timing reference value θ_ref is larger than an advance limit value θ_lim(−). The setting of the advance limit value θ_lim(−) will be described later.
In this process P9, when determining that the ignition timing reference value θ_ref is larger than the advance limit value θ_lim(−) (YES), the function F2 executes a process P10 for setting the corrected ignition timing θ′ to the advance limit value θ_lim(−), and ends the processing flow illustrated in
When determining that the ignition timing correction amount Δθ is 0 or more (NO) in the process P8 described above, the function F2 executes a process P12 for determining whether the ignition timing reference value θ_ref is larger than a retardation limit value θ_lim(+). In this process P12, when determining that the ignition timing reference value θ_ref is equal to or less than the retardation limit value θ_lim(+) (NO), the function F2 executes the process P11 for setting the corrected ignition timing θ′ to the ignition timing reference value θ ref, and ends the processing flow illustrated in
On the other hand, in the process P12, when determining that the ignition timing reference value θ_ref is larger than the retardation limit value θ_lim(+) (YES), the function F2 executes a process P13 for setting the corrected ignition timing θ′ to the retardation limit value θ_lim(+), and ends the processing flow illustrated in
Here, the setting of the advance limit value θ_lim(−) will be described. The advance limit value θ_lim(−) is a limit value of the ignition timing θ when the ignition timing θ is advanced, and is set on the basis of, for example, the ignition timing θ at which abnormal combustion occurs in the engine 1.
More specifically, for example, the ignition timing θ at which the abnormal combustion occurs is mapped according to the operating conditions such as the torque τ and the rotation speed of the engine 1 and the coolant temperature T_cw. Then, the advance limit value θ_lim(−) at which the abnormal combustion does not occur is set on the basis of the ignition timing θ at which the abnormal combustion occurs, the ignition timing θ being derived from the map using the actual operating conditions and the coolant temperature T_cw.
When the map as described above is not used, for example, the ignition timing θ at which abnormal combustion occurs may be calculated by the function F2 of correcting the ignition timing of the control device 10 from the relationship between the detection result of the knock sensor S7 and the ignition timing θ. In this case, the function F2 sets the advance limit value θ_lim(−) at which the abnormal combustion does not occur on the basis of the calculated ignition timing θ at which the abnormal combustion occurs.
When the torque τ of the engine 1 is smaller than friction torque for operating the engine 1, the engine 1 cannot be operated. Therefore, the advance limit value θ_lim(−) of the advance control is set on the basis of the range in which the rotation of the engine 1 as the internal combustion engine can be continued. That is, when the torque τ of the engine 1 is small and the difference between the torque τ of the engine and the friction torque is smaller than a predetermined value, the advance limit value θ_lim(−) is set on the basis of the relationship between the torque τ of the engine 1 and the friction torque.
More specifically, for example, the friction torque is mapped according to the operating condition of the engine 1 and the coolant temperature T_cw. Then, friction torque τ_f is derived from the map using the actual operating conditions and the coolant temperature T_cw. Further, from the relationship with the required torque τ_req (indicated torque τ_a transmitted to the crankshaft la by combustion of the air-fuel mixture at the optimum ignition timing θo) under the operating condition, the advance limit value θ_lim(−) is calculated by the following Expression (5).
θ_lim(−)=θ_mbt−{(τ_a−τ_f)/(C×τ_f)}0.5 (5)
In the above Expression (5), θ_mbt represents the ignition timing θ at which the indicated torque τ_a of the engine 1 is maximized, and C represents a coefficient of an equation obtained by approximating the energy distribution η_i to the power of the engine 1 with respect to the ignition timing θ by a quadratic function of the ignition timing θ. The approximate expression is expressed by the following Expression (6).
η_i(θ)=η_i_max+C×(θ−θ_mbt)2 (6)
In the above Expression (6), η_i_max is a maximum value of the energy distribution η_i to the power of the engine 1. When the approximate expression is not used, it is also possible to map the energy distribution η_i to the power of the engine 1 according to the ignition timing e and derive the advance limit value θ_lim(−) from the map. As illustrated in
The advance limit value θ_lim(−) in the process P9 of
Next, setting of the above-described retardation limit value θ_lim(+) will be described. The retardation limit value θ_lim(+) is a limit value of the ignition timing θ in a case where the ignition timing θ is retarded. For example, when the retard of the ignition timing θ is increased in the engine 1, the retardation limit value θ_lim(+) is set on the basis of the ignition timing θ in which the combustion state becomes unstable and the fluctuation of the torque τ of the engine 1 becomes large.
More specifically, for example, the ignition timing θ at which the fluctuation of the torque τ becomes larger than a predetermined threshold is mapped according to the operating condition such as the torque τ and the rotation speed of the engine 1 and the coolant temperature T_cw. Then, the retardation limit value θ_lim(+) at which the fluctuation of the torque τ becomes equal to or less than the threshold is set on the basis of the ignition timing θ at which the fluctuation of the torque τ derived from the map using the actual operation condition and the coolant temperature T_cw becomes large.
When the map as described above is not used, for example, the ignition timing θ at which the torque τ becomes unstable may be calculated by the function F2 of correcting the ignition timing of the control device 10 on the basis of the relationship between the ignition timing θ and the fluctuation of the rotation speed of the engine 1 based on the detection result of the crank angle sensor S1. In this case, the function F2 sets the retardation limit value θ_lim(+) at which the torque τ is not destabilized on the basis of the calculated ignition timing θ at which the torque τ becomes unstable.
When the torque τ of the engine 1 is smaller than friction torque for operating the engine 1, the engine 1 cannot be operated. Therefore, the retardation limit value θ_lim(+) of the retardation control is set on the basis of the range in which the rotation of the engine 1 as the internal combustion engine can be continued. That is, when the torque τ of the engine 1 is small and the difference between the torque τ of the engine and the friction torque is smaller than a predetermined value, the retardation limit value θ_lim(+) is set on the basis of the relationship between the torque τ of the engine 1 and the friction torque.
More specifically, for example, similarly to the advance limit value θ_lim(−) described above, the retardation limit value θ_lim(+) is calculated by the following Expression (7) from the relationship with the required torque τ_req (indicated torque τ_a at the optimum ignition timing eo) under the actual operating condition.
θ_lim(+)=θ_mbt−{(τ_a−τ_f)/(C×τ_f)}0.5 (7)
Similarly to the advance limit value θ_lim(−) described above, when the approximate expression of Expression (6) is not used, it is also possible to map the energy distribution η_i to the power of the engine 1 according to the ignition timing e and derive the retardation limit value θ_lim(+) from the map.
Hereinafter, the operation of the control device 10 of an internal combustion engine according to the present embodiment will be described.
It is expected that regulations on fuel consumption and exhaust of vehicles such as automobiles will be further strengthened in the future. In particular, the regulations on fuel consumption have been attracting increasing attention due to problems such as recent fuel price increase, influence on global warming, and energy resource depletion. In order to cope with the regulations on automobile fuel consumption that is strengthened year by year, the market of hybrid vehicles having a high fuel consumption reduction effect is expanding.
A hybrid vehicle includes a motor and an engine as power sources, and drives both the motor and the engine or one of the motor and the engine according to traveling conditions, thereby efficient1y traveling the vehicle. The hybrid vehicle converts kinetic energy of the vehicle into electric energy using the motor as a generator at the time of deceleration, stores the electric energy in the power storage device, and drives the motor using the electric energy to drive the vehicle, thereby improving fuel consumption.
For example, the engine of the series hybrid vehicle frequent1y stops the operation as compared with a normal automobile or a parallel hybrid vehicle. More specifically, the engine of the series hybrid vehicle improves the fuel consumption by operating under a limited condition, for example, at the time of charging the power storage device or at the time of power generation when the output of the power storage device is insufficient. However, since the operation time of the engine is shortened, the energy distribution from the engine to the exhaust gas and the energy distribution from the engine to the coolant are reduced, and the catalyst temperature of the exhaust system and the coolant temperature are likely to decrease as compared with an automobile driven by the engine.
In the conventional waste heat control device described in PTL 1, a certain effect can be obtained when the waste heat recovery of the engine by the coolant is mainly performed. However, this conventional waste heat control device has a problem that the operation frequency of the engine is low, and it is not possible to cope with a situation in which both the temperature of the catalyst included in the exhaust system of the engine and the temperature of the coolant are low.
On the other hand, the control device 10 of the internal combustion engine of the present embodiment is a device that acquires the coolant temperature T_cw and the catalyst temperature T_cat of the exhaust system to control the ignition timing θ of the engine 1, which is the internal combustion engine, as described above. As described above, the control device 10 executes the coolant heating control in the process P2 illustrated in
With such a configuration, the control device 10 of the internal combustion engine of the present embodiment can increase the catalyst temperature T_cat and the coolant temperature T_cw more efficient1y than the conventional waste heat control device. More specifically, by correcting the ignition timing θ on the basis of the catalyst temperature T_cat and the coolant temperature T_cw which are important parameters of the internal combustion engine, it is possible to operate the energy distribution η_i to the power of the engine 1, the energy distribution η_exh to the exhaust gas, and the energy distribution η_cw to the coolant illustrated in
The control device 10 of the internal combustion engine of the present embodiment executes advance control for advancing the ignition timing θ in the coolant heating control executed in the above-described process P2. The control device 10 executes retardation control for delaying the ignition timing θ in the catalyst heating control executed in the above-described process P5.
With such a configuration, in the coolant heating control, as illustrated in
When the setting C2 is selected in the advance control executed in the above-described process P2, the control device 10 of the internal combustion engine of the present embodiment increases the ignition timing correction amount Δθ as the advance correction amount for advancing the ignition timing θ as the coolant temperature deviation ΔT_cw, which is the difference between the first threshold T1 and the coolant temperature T_cw, increases. With such a configuration, as illustrated in
When the setting C4 is selected in the retardation control executed in the above-described process P5, the control device 10 of the internal combustion engine of the present embodiment increases the ignition timing correction amount Δθ as the retardation correction amount that delays the ignition timing θ as the catalyst temperature deviation ΔT_cat, which is the difference between the second threshold T2 and the catalyst temperature T_cat, increases. With such a configuration, as illustrated in
In the advance control, as illustrated in
In the above-described retardation control, when the ignition timing correction amount Δθ as the retardation correction amount exceeds the retardation limit value θ_lim(+) as illustrated in
In the control device 10 for the internal combustion engine according to the present embodiment, the advance limit value θ_lim(−) is set on the basis of either the ignition timing θ at which abnormal combustion of the engine 1, which is an internal combustion engine, occurs or the ignition timing at which the power-coolant distribution η_i+η_cw is maximized. The power-coolant distribution η_i+η_cw is the sum of the energy distribution η_i to the power of the engine 1, that is, the drive system and the energy distribution η_cw to the coolant. With such a configuration, in the coolant heating control for increasing the temperature of the coolant, the power of the engine 1 and the energy used for increasing the temperature of the coolant can be maximized, and the utilization efficiency of the energy of the entire system can be improved.
In the control device 10 for the internal combustion engine according to the present embodiment, the above-described retardation limit value θ_lim(+) is set on the basis of the ignition timing at which the combustion state of the engine 1 as the internal combustion engine becomes unstable. With such a configuration, in the catalyst heating control for increasing the temperature of the catalyst temperature T_cat, the combustion state of the engine 1 can be stabilized, the fluctuation of the torque τ can be prevented, and the torque τ can be stabilized.
In the control device 10 of the internal combustion engine of the present embodiment, the advance limit value θ_lim(−) of the advance control and the retardation limit value θ_lim(+) of the retardation control described above are set on the basis of the range in which the rotation of the engine 1 as the internal combustion engine can be continued. With such a configuration, the torque τ of the engine 1 can be prevented from becoming smaller than the friction torque, and the engine 1 can be reliably driven.
As described above, according to the present embodiment, it is possible to provide the control device 10 of the internal combustion engine capable of increasing the catalyst temperature T_cat and the coolant temperature T_cw more efficient1y than the conventional waste heat control device.
Next, a second embodiment of the control device of the internal combustion engine according to the present disclosure will be described with reference to
As illustrated in
τ_0=η_i(θ0)×Mf×Hl/(2×Π×R) (8)
Here, η_i(θ0) is an energy distribution η_i to the power of the engine 1 at an ignition timing θ0. Mf is a fuel supply amount [kg] per cycle of the engine 1, Hl is a low calorific value [J/kg] of the fuel, n is a circular constant, and R is a crank radius [m]. The torque τ_0 of the engine 1 based on the ignition timing θ before correction calculated as described above is considered to be equivalent to the required torque τ_req.
Next, the function F3 of correcting the torque τ executes a process P22 for calculating torque τ_m based on the corrected ignition timing Gθ40 by the following Expression (9). Here, η_i (θm) is an energy distribution η_i to the power of the engine 1 at an ignition timing θm.
τ_m=η_i(θm)×Mf×Hl/(2×Π×R) (9)
Next, the function F3 of correcting the torque τ executes a process P23 for calculating the torque decrease amount Δτ by subtracting the torque τ_m at the corrected ignition timing θ′ calculated in the process P22 from the torque τ_0 of the engine 1 at the corrected ignition timing θ calculated in the process P21.
Next, the function F3 of correcting the torque τ executes a process P24 for calculating a correction amount ΔP_thr of the thrott1e opening degree. The correction amount ΔP_thr of the thrott1e opening degree is a correction amount of the thrott1e opening degree P_thr for compensating the decrease amount of the torque τ due to the corrected ignition timing θ′ and generating the torque τ due to the ignition timing θ before correction.
In the control device 10, for example, a map indicating the relationship between the thrott1e opening degree P_thr of the electronically controlled thrott1e 1c and an air flow rate FR_air is stored in the ROM 14. The function F3 of correcting the torque τ obtains the current air flow rate FR_air on the basis of the current thrott1e opening degree P_thr from the map. Further, the function F3 uses the flow rate FR_air of the air before correction, the corrected torque decrease amount Δτ, and the torque τ_0 before correction to obtain a corrected air flow rate FR_air′ expressed by the following Expression (10).
FR_air′=FR_air×(1+Δτ/τ_0) (10)
Then, the function F3 calculates a correction amount ΔP_thr of the thrott1e opening degree that realizes the corrected air flow rate FR_air′ on the basis of the current thrott1e opening degree P_thr. Next, the function F3 of correcting the torque τ executes a process P25 of adding the calculated correction amount ΔP_thr of the thrott1e opening degree and the current thrott1e opening degree P_thr to obtain the corrected thrott1e opening degree P_thr′ for realizing the corrected air flow rate FR_air′. Thus, the processing flow illustrated in
In each of the graphs excluding the graph indicating on and off of the engine 1 in
As illustrated in
As a result, in the setting C2 of the advance control by the control device 10 of the first embodiment, energy is supplied as heat from the engine 1 to the coolant in the on state in which the engine 1 is operating. As a result, as indicated by a chain line in the graph of the coolant temperature T_cw in
On the other hand, in the setting C2 of the advance control by the control device 10 of the present embodiment, each process illustrated in
As a result, as illustrated in the graph of the torque τ, in the setting C2 of the advance control by the control device 10 of the present embodiment, a decrease in the torque τ with respect to the required torque τ_req occurring in the setting C2 of the advance control by the control device 10 of the first embodiment is prevented. Therefore, in the setting C2 of the advance control by the control device 10 of the present embodiment, torque equivalent to the required torque τ_req can be generated.
In the setting C2 of the advance control by the control device 10 of the present embodiment, the thrott1e opening degree P_thr is increased more than the setting C2 of the advance control by the control device 10 of the first embodiment from time t0 to time t1 when the coolant temperature T_cw is equal to or less than the first threshold T1. As a result, in the setting C2 of the advance control by the control device 10 of the present embodiment, the flow rate of air taken into the engine 1 is increased as compared with the setting C2 of the advance control by the control device 10 of the first embodiment, and the energy distribution η_cw from the engine 1 to the coolant can be increased.
Therefore, the control device 10 of the present embodiment can increase the coolant temperature T_cw in a shorter time and can make the final coolant temperature T_cw higher as compared with the control device 10 of the first embodiment. It also allows the engine 1 to generate the required torque τ_req during the execution of the coolant heating control. Therefore, the energy distribution η_cw to the coolant can be increased while the required torque τ_req is satisfied, and both the performance of the system and the performance improvement of the system using the energy of the coolant, for example, heating, can be achieved.
Examples of the condition that the required torque τ_req needs to be satisfied include an idle operation condition in which the torque τ equivalent to the friction torque needs to be continuously generated, and a high-speed/high-output operation condition in which the output of the power storage device 4 is insufficient and the motor 5 is driven by the output of the generator 2.
In each of the graphs excluding the graph indicating on and off of the engine 1 in
As illustrated in
As a result, in the setting C4 of the retardation control by the control device 10 of the first embodiment, energy is supplied as heat from the engine 1 to the exhaust gas in the on state in which the engine 1 is operating.
As a result, the catalyst temperature T_cat gradually rises as indicated by a chain line in the graph of the catalyst temperature T_cat in
On the other hand, in the setting C4 of the retardation control by the control device 10 of the present embodiment, each process illustrated in
As a result, as illustrated in the graph of the torque τ, in the setting C4 of the retardation control by the control device 10 of the present embodiment, a decrease in the torque τ with respect to the required torque τ_req occurring in the setting C4 of the retardation control by the control device 10 of the first embodiment is prevented. Therefore, in the setting C4 of the retardation control by the control device 10 of the present embodiment, torque equivalent to the required torque τ_req can be generated.
That is, the control device 10 of the present embodiment increases the thrott1e opening degree P_thr of the internal combustion engine so as to compensate for the torque τ of the internal combustion engine reduced by the advance control or the retardation control. With this configuration, a decrease in the torque τ of the engine 1 is prevented by the advance control or the retardation control by the control device 10, and torque equivalent to the required torque τ_req can be generated.
In the setting C4 of the retardation control by the control device 10 of the present embodiment, the thrott1e opening degree P_thr is increased more than the setting C4 of the retardation control by the control device 10 of the first embodiment from time t0 to time t1 when the catalyst temperature T_cat is equal to or lower than the second threshold T2. As a result, in the setting C4 of the retardation control by the control device 10 of the present embodiment, the flow rate of air taken into the engine 1 is increased as compared with the setting C4 of the retardation control by the control device 10 of the first embodiment, and the energy distribution η_exh from the engine 1 to the exhaust gas can be increased.
Therefore, the control device 10 of the present embodiment can increase the catalyst temperature T_cat in a shorter time and make the final catalyst temperature T_cat higher as compared with the control device 10 of the first embodiment. It also allows the engine 1 to generate the required torque τ_req during the execution of the catalyst heating control. Therefore, it is possible to increase the energy distribution η_exh to the exhaust gas while satisfying the required torque τ_req, and to achieve both the performance of the system and the improvement of the exhaust purification performance by the catalyst of the exhaust system such as the three-way catalyst 1h.
Examples of the condition that the required torque τ_req needs to be satisfied include an idle operation condition in which the torque τ equivalent to the friction torque needs to be continuously generated, and a high-speed/high-output operation condition in which the output of the power storage device 4 is insufficient and the motor 5 is driven by the output of the generator 2.
Next, a third embodiment of the control device of the internal combustion engine according to the present disclosure will be described with reference to
As illustrated in
In the process P32, the function F0 of calculating the distribution of the ignition correction sets the flag F to “mode M1” and ends the process illustrated in
On the other hand, in the process P31, when the function F0 of calculating the allocation of the ignition correction determines that the catalyst temperature T_cat is higher than the third threshold T3 (NO), the function F0 executes the next process P33. In the process P33, the function F0 determines whether the catalyst temperature T_cat is equal to or lower than the second threshold T2 which is a predetermined temperature threshold. As described above, the second threshold T2 is set to a temperature higher than the third threshold T3. In this process P33, when determining that the catalyst temperature T_cat is equal to or lower than the second threshold T2 (YES), the function F0 executes the next process P34.
In the process P34, the function F0 of calculating the distribution of the ignition correction determines whether the coolant temperature T_cw is equal to or less than the first threshold T1. In the process P34, when determining that the coolant temperature T_cw is higher than the first threshold T1 (NO), the function F0 executes the above-described process P32, sets the flag F to the mode M1 in which heating of the three-way catalyst 1h is prioritized, and ends the processing flow illustrated in
In the process P35, the function F0 of calculating the distribution of the ignition correction sets the flag F to “mode M2” and ends the process illustrated in
On the other hand, in the process P33, when the function F0 of calculating the distribution of the ignition correction determines that the catalyst temperature T_cat is higher than the second threshold T2 (NO), the function F0 executes the next process P36. In the process P36, the function F0 determines whether the coolant temperature T_cw is equal to or lower than the first threshold T1 as in the process P34 described above. In the process P36, when the function F0 determines that the coolant temperature T_cw is equal to or lower than the first threshold T1 (YES), the function F0 executes the next process P37.
In the process P37, the function F0 of calculating the distribution of the ignition correction sets the flag F to “mode M3” and ends the process illustrated in
In the process P38, the function F0 of calculating the distribution of the ignition correction sets the flag F to “mode M4” and ends the process illustrated in
When the processing flow illustrated in
In the process P41, when determining that the flag F is the mode M1 in which heating of the catalyst is prioritized (YES), the function F1 of calculating the ignition timing correction amount Δθ executes the next process P42.
In the process P42, the function F1 executes catalyst heating control for increasing the energy distribution η_exh from the engine 1 to the exhaust gas, similarly to the process P5 by the function F1 of the first embodiment described above.
More specifically, in the process P42, the function F1 executes the retardation control for setting the ignition timing correction amount Δθ to a positive value, and ends the processing flow illustrated in
On the other hand, in the process P41, when the function F1 of calculating the ignition timing correction amount Δθ determines that the flag F is not the mode M1 that prioritizes the heating of the catalyst (NO), the next process P43 is executed. In the process P43, the function F1 determines whether the flag F is the mode M2 in which heating of the catalyst and heating of the coolant are simultaneously performed. In the process P43, when it is determined that the flag F indicates the mode M2 in which heating of the catalyst and heating of the coolant are simultaneously performed (YES), the function F1 executes the next process P44 to the process P46.
In the processes P44 to P46, the function F1 of calculating the ignition timing correction amount Δθ selects the ignition timing correction amounts Δθa and Δθb so as to execute the retardation control on some cylinders 1d and the advance control on the other cylinders 1d among the plurality of cylinders 1d constituting the engine 1 as the internal combustion engine.
More specifically, in the process P44, the function F1 of calculating the ignition timing correction amount Δθ calculates, for example, a positive ignition timing correction amount Δθa as a retardation correction amount for the cylinders 1d of #2 and #4 among the plurality of cylinders 1d constituting the engine 1 illustrated in
The cylinder 1d that performs the advance control or the retardation control is not limited to the above combination.
The method of calculating the ignition timing correction amount Δθa which is the retardation correction amount and the ignition timing correction amount Δθb which is the advance correction amount is similar to those in the first and second embodiments.
In the process P46, the function F1 of calculating the ignition timing correction amount Δθ selects the ignition timing correction amounts Δθa and Δθb on the basis of, for example, a torque decrease amount Δτa by the retardation control and a torque decrease amount Δτb by the advance control. The torque decrease amount Δτa by the retardation control and the torque decrease amount Δτb by the advance control can be calculated on the basis of, for example, the following Expressions (11) and (12).
Δτa={η_i(θ)−η_i(θ+Δθa)}×Mf×Hl/(2×Π×R) (11)
Δτb={η_i(θ)−η_i(θ+Δθb)}×Mf×Hl/(2×Π×R) (12)
Here, Δτa is the torque decrease amount by the retardation control, Δτb is the torque decrease amount by the advance control, and η_i(θ) is the energy distribution η_i to the power of the engine 1 at the ignition timing θ.
Mf is a fuel supply amount [kg] per cycle of the engine 1, Hl is a low calorific value [J/kg] of the fuel, n is a circular constant, and R is a crank radius [m].
In the process P46, the function F1 of calculating the ignition timing correction amount Δθ selects the ignition timing correction amount Δθb calculated in the process P45 as the ignition timing correction amount Δθ of the advance control, for example, when the torque decrease amount Δτa of the retardation control is larger than the torque decrease amount Δτb of the advance control. In this case, the function F1 calculates, as the ignition timing correction amount Δθ of the retardation control, the ignition timing correction amount Δθa by which the torque decrease amount Δτa of the retardation control is equivalent to the torque decrease amount Δτb of the advance control, for example, by the following Expression (13).
Δθa=θ_mbt−θ+{2×ΠR×Δρa/(C×Mf×Hl)+(θ−θ_mbt)2}0.5 (13)
In the above Expression (13), θ_mbt represents the ignition timing θ at which the indicated torque τ_a of the engine 1 is maximum, n represents the circular constant, R represents the crank radius [m], Mf represents the fuel supply amount [kg] per cycle of the engine 1, and Hl represents the low calorific value [J/kg] of the fuel. C is a coefficient of an equation in which the energy distribution η_i to the power of the engine 1 with respect to the ignition timing θ is approximated by a quadratic function of the ignition timing θ. The approximate expression is expressed by the above Expression (6). When the approximate expression is not used, the energy distribution η_i to the power of the engine 1 according to the ignition timing θ is mapped, and the ignition timing correction amount Δθa in which the torque decrease amount Δτa of the retardation control is equivalent to the torque decrease amount Δτb of the advance control can be derived from the map.
In the process P46, the function F1 of calculating the ignition timing correction amount Δθ selects the ignition timing correction amount Δθa calculated in the process P44 as the ignition timing correction amount Δθ of the retardation control, for example, when the torque decrease amount Δτb of the advance control is larger than the torque decrease amount Δτa of the retardation control. In this case, the function F1 calculates, as the ignition timing correction amount Δθ of the advance control, the ignition timing correction amount Δθb by which the torque decrease amount Δτb of the advance control is equivalent to the torque decrease amount Δτa of the retardation control, for example, by the following Expression (14).
Δθb=θ_mbt−θ+{2×Π×R×Δτb/(C×Mf×Hl)+(θ−θ_mbt)2}0.5 (14)
In the above Expression (14), θ_mbt, Π, R, Mf, H1, and the like are the same as those in the above Expression (13). When the approximate expression is not used, the energy distribution η_i to the power of the engine 1 according to the ignition timing θ is mapped, and the ignition timing correction amount Δθb in which the torque decrease amount Δτb of the advance control is equivalent to the torque decrease amount Δτa of the retardation control can be derived from the map.
As described above, in the function F1 of calculating the ignition timing correction amount Δθ, the ignition timing correction amounts Δθa and Δθb are selected so that the retardation control is performed in some cylinders 1d and the advance control is performed in the other cylinders 1d among the plurality of cylinders 1d of the engine 1 in the processes P44 to P46. Thereafter, the function F1 ends the processing flow illustrated in
On the other hand, in the process P43 described above, when the function F1 of calculating the ignition timing correction amount Δθ determines that the flag F is not the mode M2 for simultaneously heating the catalyst and the coolant (NO), the next process P47 is executed. In the process P47, the function F1 determines whether the flag F is in the mode M3 in which the heating of the coolant is prioritized.
In the process P47, when the function F1 of calculating the ignition timing correction amount Δθ determines that the flag F is the mode M3 that prioritizes the heating of the coolant (YES), the next process P48 is executed. In the process P48, the function F1 executes the coolant heating control for increasing the energy distribution η_cw from the engine 1 to the coolant similarly to the process P2 by the function F1 of the first embodiment described above. More specifically, in the process P48, the function F1 executes advance control for setting the ignition timing correction amount Δθ to a negative value, and ends the processing flow illustrated in
On the other hand, in the process P47, when the function F1 of calculating the ignition timing correction amount Δθ determines that the flag F is not the mode M3 that prioritizes the heating of the coolant (NO), the next process P49 is executed. In the process P49, the function F1 sets the ignition timing correction amount Δθ to zero similarly to the process P3 by the function F1 of the first embodiment described above, and ends the processing flow illustrated in
In the graphs excluding the graph indicating on and off of the engine 1 and the graph indicating the flag F in
As illustrated in
The control device of the comparative embodiment performs retardation control to delay the ignition timing θ from the optimum ignition timing θo at the time of starting the engine 1, and the thrott1e opening degree P_thr is set so as to satisfy the required torque τ_req. By the control of the control device of this comparative embodiment, energy is supplied to the three-way catalyst 1h which is a catalyst of the exhaust system during the operation of the engine 1, and the catalyst temperature T_cat increases. When the catalyst temperature T_cat exceeds a predetermined threshold at time t2, the control device of the comparative embodiment stops the retardation control and returns the ignition timing θ to the optimum ignition timing θo.
On the other hand, in the engine 1 controlled by the control device 10 of the present embodiment, the catalyst temperature T_cat is equal to or lower than the third threshold T3 from time t0 to time t1. Therefore, the control device 10 executes the process P32 illustrated in
As a result, as illustrated in
In the engine 1 controlled by the control device 10 of the present embodiment, as indicated by a broken line in
As a result, the control device 10 of the present embodiment executes the process P44 to the process P46 illustrated in
More specifically, the control device 10 of the present embodiment executes the advance control in the cylinders 1d of #1 and #3 of the engine 1 and executes the retardation control in the cylinders 1d of #2 and #4 of the engine 1, for example, during a period from time t1 to time t2. The advance control may be executed in the cylinders 1d of #1 and #4 of the engine 1, and the retardation control may be executed in the cylinders ld of #2 and #3 of the engine 1. As a result, between time t1 and time t2, the energy distribution η_cw from the engine 1 to the coolant is increased as compared with the engine 1 controlled by the control device of the comparative embodiment, and the coolant temperature T_cw can be increased earlier.
In the engine 1 controlled by the control device 10 of the present embodiment, the catalyst temperature T_cat exceeds the third threshold T3 and the second threshold T2 and the coolant temperature T_cw is equal to or lower than the first threshold T1 between time t2 and time t3 as indicated by a broken line in
As a result, the control device 10 of the present embodiment executes the process P48 illustrated in
Thereafter, in the engine 1 controlled by the control device 10 of the present embodiment, the coolant temperature T_cw exceeds the first threshold T1 at time t3 as indicated by a broken line in
As a result, the control device 10 of the present embodiment executes the process P49 illustrated in
Hereinafter, the operation of the control device 10 of the present embodiment will be described.
As described above, when the catalyst temperature T_cat is equal to or lower than the third threshold T3 lower than the second threshold T2, the control device 10 of the present embodiment increases the energy distribution η_exh to the exhaust gas to be larger than the energy distribution η_cw to the coolant in the catalyst heating control described above. With this configuration, when the temperature of the three-way catalyst 1h is lower than the predetermined third threshold T3, the temperature of the three-way catalyst 1h can be rapidly increased by giving priority to the heating of the three-way catalyst 1h, and the purification performance of exhaust can be improved.
When the catalyst temperature T_cat is higher than the second threshold T2 and the coolant temperature T_cw is equal to or lower than the first threshold T1, the control device 10 of the present embodiment increases the energy distribution η_cw to the coolant to be larger than the energy distribution η_exh to the exhaust gas in the coolant heating control. With this configuration, the temperature of the coolant can be rapidly increased, the efficiency of the engine 1 can be improved, and the heating can be rapidly used.
When the catalyst temperature T_cat is equal to or lower than the second threshold T2 and the coolant temperature T_cw is equal to or lower than the first threshold T1, the control device 10 of the present embodiment executes the retardation control on some cylinders 1d among the plurality of cylinders ld constituting the internal combustion engine and executes the advance control on the other cylinders 1d. With this configuration, the coolant temperature T_cw and the catalyst temperature T_cat can be efficient1y increased.
The control device 10 of the present embodiment may alternately execute the retardation control and the advance control in all the cylinders 1d when the catalyst temperature T_cat is equal to or lower than the second threshold T2 and the coolant temperature T_cw is equal to or lower than the first threshold T1. More specifically, the retardation control and the advance control may be switched every predetermined number of cycles of the engine 1. With this configuration, the coolant temperature T_cw and the catalyst temperature T_cat can be efficient1y increased. Since the ignition timing θ is the same among the plurality of cylinders 1d, control is facilitated as compared with a case where the ignition timing θ is set separately for some cylinders 1d and the other cylinders 1d.
The control device 10 of the present embodiment determines the retardation correction amount of the retardation control and the advance correction amount of the advance control so that the torques τ of all the cylinders 1d become equal. With this configuration, the operation of the engine 1 can be stabilized.
As described above, according to the control device 10 of the present embodiment, the ignition timing correction amount Δθ is set on the basis of the state of the catalyst temperature T_cat and the coolant temperature T_cw, and the advance control and the retardation control of the ignition timing θ are switched, so that the catalyst temperature T_cat can be quickly raised to the target temperature. By switching the distribution of the energy of the engine 1 in this manner, it is possible to achieve both the improvement of the exhaust performance and the improvement of the heating performance due to the increase in the coolant temperature. In each of the above-described embodiments, an example has been described in which the ignition timing θ is set so as to have a correlation with the difference between the catalyst temperature T_cat and the coolant temperature T_cw and the respective thresholds. However, the ignition timing θ may be set to the advance limit value θ_lim(−) or the retardation limit value θ_lim(+).
As described above, the embodiment of the control device of an internal combustion engine according to the present disclosure has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and there are design changes and the like without departing from the gist of the disclosure, which are also included in the disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2020-060879 | Mar 2020 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2021/001178 | 1/15/2021 | WO |
