Vehicle

Abstract

To provide a vehicle which suppresses variations in filter temperature caused by temperature rise control at starting-up of an engine.SOLUTION: A vehicle comprises an engine that is a driving power source, a filter for collecting exhaust particulates from the engine, and a control device. The control device includes a temperature rise control unit that raises the temperature of the filter by retard processing of ignition timing of the engine, and a retard amount control unit that reduces the amount of retard of the ignition timing in cold starting of the engine as compared with the amount of retard of the ignition timing in warm starting of the engine.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a vehicle.

Background Art

[0002] There are cases where regeneration control of a filter is required to prevent clogging of the filter. When the temperature of the filter is low when regeneration control is required, temperature increase control is executed to increase the exhaust heat amount by retarding the ignition timing and raise the temperature of the filter (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the engine is cold-started and when it is warm-started, the load on the engine is different and the exhaust heat amount of the engine is also different. Therefore, if temperature increase control is executed at engine start, the temperature of the filter after temperature increase may vary.

[0005] Therefore, an object of the present invention is to provide a vehicle that suppresses variations in the temperature of a filter due to temperature increase control at engine start.

Means for Solving the Problems

[0006] The above object is achieved by including an engine as a driving power source, a filter that collects exhaust particulate matter from the engine, and a control device, where the control device includes a temperature increase control unit that raises the temperature of the filter by retarding the ignition timing of the engine, The variation in the exhaust heat quantity of the engine due to the retardation process during cold start and warm start of the engine is suppressed. and a retard angle amount control unit that reduces the retard angle amount of the ignition timing at cold start of the engine compared to the retard angle amount of the ignition timing at warm start of the engine. See, the retard angle amount control unit decreases the retard angle amount as the engine speed increases, decreases the retard angle amount as the in-cylinder air amount of the engine increases, and when the engine speed and the in-cylinder air amount are the same, decreases the retard angle amount of the ignition timing during cold start of the engine compared to the retard angle amount of the ignition timing during warm start of the engine. It can be achieved by a vehicle.

[0008] The vehicle may include a motor as a driving power source and a battery that exchanges power with the motor.

Advantages of the Invention

[0009] According to the present invention, it is possible to provide a vehicle that suppresses variations in the temperature of a filter by temperature rise control at engine startup.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0011] [Schematic Configuration of Hybrid Vehicle] FIG. 1 is a schematic configuration diagram of a hybrid vehicle 1. The hybrid vehicle 1 is equipped with an engine 10 and a motor 15 as driving power sources for traveling. The engine 10 is a gasoline engine having a plurality of cylinders, but it may also be a diesel engine. A transmission unit 11 is provided on the power transmission path from the engine 10 to the drive wheels 13. The transmission unit 11 and the left and right drive wheels 13 are drivingly connected via a differential 12.

[0012] The transmission unit 11 is provided with a K0 clutch 14 and a motor 15. The motor 15 is provided on the power transmission path from the engine 10 to the drive wheels 13.

[0013] The K0 clutch 14 is provided between the engine 10 and the motor 15 in the same power transmission path. The K0 clutch 14 receives hydraulic pressure supply and engages to connect the power transmission between the engine 10 and the motor 15. The K0 clutch 14 becomes disengaged in response to the stop of the hydraulic pressure supply to cut off the power transmission between the engine 10 and the motor 15. Further, the K0 clutch 14 is in a slip state from the start of torque transmission until full engagement.

[0014] The motor 15 is connected to the battery 16 via the inverter 17. The battery 16 is a rechargeable secondary battery such as a nickel-hydrogen battery or a lithium-ion battery. The motor 15 functions as a motor that generates driving force for the vehicle in response to power supply from the battery 16. Further, the motor 15 also functions as a generator that generates electric power for charging the battery 16 in response to power transmission from the engine 10 or the drive wheels 13. The electric power exchanged between the motor 15 and the battery 16 is adjusted by the inverter 17.

[0015] The transmission unit 11 is provided with a torque converter 18 and an automatic transmission 19. The torque converter 18 is a fluid coupling having a torque amplification function. The automatic transmission 19 is a stepped transmission that switches the gear ratio in multiple steps. The torque converter 18 is provided between the motor 15 and the drive wheels 13 on the above power transmission path. The automatic transmission 19 is provided between the torque converter 18 and the drive wheels 13 on the above power transmission path. The torque converter 18 is provided with a lock-up clutch (hereinafter referred to as the LU clutch) 20 that receives hydraulic pressure supply and engages to directly connect the motor 15 and the automatic transmission 19.

[0016] The LU clutch 20 receives hydraulic pressure supply and engages to connect the power transmission between the motor 15 and the drive wheels 13. The LU clutch 20 becomes disengaged in response to the stop of the hydraulic pressure supply. Further, the LU clutch 20 is in a slip state from disengagement to engagement.

[0017] The speed change unit 11 is further provided with an oil pump 21 and a hydraulic control mechanism 22. The hydraulic pressure generated by the oil pump 21 is supplied to the K0 clutch 14, the torque converter 18, the automatic transmission 19, and the LU clutch 20 respectively through the hydraulic control mechanism 22. The hydraulic control mechanism 22 is provided with respective hydraulic circuits of the K0 clutch 14, the torque converter 18, the automatic transmission 19, and the LU clutch 20, and various hydraulic control valves for controlling their operating hydraulic pressures.

[0018] The hybrid vehicle 1 is provided with an ECU (Electronic Control Unit) 50 as a control device of the vehicle. The ECU 50 is an electronic control unit including an arithmetic processing circuit that performs various arithmetic processes related to the running control of the vehicle, and a memory in which control programs and data are stored. The ECU 50 is an example of a vehicle control device, and specifically, it functionally realizes a warm-up control unit and a retard angle control unit which will be described later in detail.

[0019] An ignition switch 61, a crank angle sensor 62, an air flow meter 63, air-fuel ratio sensors 64 and 65, and a water temperature sensor 66 are connected to the ECU 50. The ignition switch 61 detects the on / off of the ignition. The crank angle sensor 62 detects the rotational speed of the crankshaft of the engine 10. The air flow meter 63 detects the intake air amount introduced into the engine 10. The air-fuel ratio sensors 64 and 65 detect the air-fuel ratio of the exhaust gas of the engine 10. The water temperature sensor 66 detects the temperature of the cooling water that cools the engine 10.

[0020] The ECU 50 controls the driving of the engine 10 and the motor 15. Specifically, the ECU 50 controls the inverter 17 to adjust the amount of power transfer between the motor 15 and the battery 16, thereby performing torque control of the motor 15. The ECU 50 performs drive control of the K0 clutch 14, the LU clutch 20, and the automatic transmission 19 through the control of the hydraulic control mechanism 22.

[0021] The ECU 50 drives the hybrid vehicle 1 in either the motor driving mode or the hybrid driving mode. In the motor driving mode, the ECU 50 disengages the K0 clutch 14 and rotates the drive wheels 13 with the power of the motor 15. In the hybrid driving mode, the ECU 50 engages the K0 clutch 14 and rotates the drive wheels 13 with the power of at least one of the engine 10 and the motor 15. For example, when the required driving force for the hybrid vehicle 1 becomes equal to or greater than the driving force threshold value, the mode is switched from the motor driving mode to the hybrid driving mode. Also, when the charge amount of the battery 16 becomes equal to or less than the power threshold value, the mode is switched from the motor driving mode to the hybrid driving mode.

[0022] [Schematic Configuration of Engine] Figure 2 is a schematic configuration diagram of the engine 10. The engine 10 has a cylinder block 30, a cylinder head 32, a piston 33, a connecting rod 34, a crankshaft 35, an intake passage 36, an intake valve 36v, an exhaust passage 37, and an exhaust valve 37v.

[0023] The cylinder block 30 is provided with a cylindrical bore 31. The piston 33 is reciprocally accommodated within the bore 31. The combustion chamber C is defined by the wall surface of the bore 31, the lower surface of the cylinder head 32, and the top surface of the piston 33. The volume of the combustion chamber C increases and decreases with the reciprocation of the piston 33.

[0024] The crankshaft 35, which is the output shaft of the engine 10, is connected via the connecting rod 34. The connecting rod 34 and the crankshaft 35 convert the reciprocating motion of the piston 33 into the rotational motion of the crankshaft 35. The engine 10 is provided with the crank angle sensor 62 described above.

[0025] The intake passage 36 is connected to the combustion chamber C via the intake valve 36v. The exhaust passage 37 is connected to the combustion chamber C via the exhaust valve 37v. The intake passage 36 is provided with the air flow meter 63 described above.

[0026] The cylinder block 30 is provided with an in-cylinder injection valve 41D that directly injects fuel into the combustion chamber C. The intake passage 36 is provided with a port injection valve 41P that injects fuel toward the intake port. The cylinder head 32 is provided with a spark plug 42 that ignites the air-fuel mixture introduced into the combustion chamber C. Note that only one of the in-cylinder injection valve 41D and the port injection valve 41P may be provided.

[0027] The exhaust passage 37 is provided with a three-way catalyst 43 and a GPF (Gasoline Particulate Filter) 44. The three-way catalyst 43 contains a catalyst metal, has an oxygen storage capacity, and purifies NOx, HC, and CO. The GPF 44 is a porous ceramic structure that collects exhaust particulate matter (hereinafter referred to as PM (Particulate Matter)) in the exhaust gas. The GPF 44 is an example of a filter. Note that, for example, when the engine 10 is a diesel engine, a DPF (Diesel Particulate Filter) is provided instead of the GPF 44.

[0028] An air-fuel ratio sensor 64 is provided between the three-way catalyst 43 and the GPF 44. The air-fuel ratio sensor 64 detects the air-fuel ratio of the exhaust gas discharged from the three-way catalyst 43. An air-fuel ratio sensor 65 is provided on the downstream side of the GPF 44. The air-fuel ratio sensor 65 detects the air-fuel ratio of the exhaust gas discharged from the GPF 44.

[0029] Based on the detection signals of the above-described sensors, the ECU 50 controls the driving of the engine 10 by controlling the opening degree of the throttle valve 40, the fuel injection amount of the in-cylinder injection valve 41D and the port injection valve 41P, the ignition timing by the spark plug 42, and the like.

[0030] The ECU 50 estimates the amount of PM deposited in the GPF 44, and when the amount of PM deposition reaches or exceeds a predetermined value, it requests regeneration control of the GPF 44. The method for estimating the amount of PM deposition may be, for example, based on the driving history of the engine 10 since the completion of the previous regeneration control, the differential pressure before and after the GPF 44, etc., or may be estimated by other known methods. In the regeneration control, for example, by executing fuel cut or controlling the air-fuel ratio to a lean air-fuel ratio, oxygen for burning the deposited PM is supplied to the GPF 44.

[0031] [Temperature increase control] When there is a regeneration request for the GPF 44 as described above and the temperature of the GPF 44 is less than a predetermined value, the ECU 50 executes temperature increase control to raise the temperature of the GPF 44 to a predetermined temperature. The temperature increase control is executed by retarding the ignition timing control to retard the ignition timing to a side later than the basic ignition timing. By retarding the ignition timing, the exhaust heat amount increases and the temperature of the GPF 44 can be raised. Therefore, by executing the regeneration control after the temperature of the GPF 44 has been increased, the PM deposited on the GPF 44 can be efficiently burned.

[0032] However, depending on the temperature of the engine 10 at the start of the engine 10, the subsequent load on the engine 10 is different, and the exhaust heat amount is also different. For example, in the case of a cold start, the friction torque of the engine 10 and the drag torque of the torque converter 18 are large. For this reason, the load on the engine 10 is large and the exhaust heat amount is also large. On the other hand, in the case of a warm start, the above-mentioned friction torque and drag torque are small, and the exhaust heat amount is also small. Therefore, if the temperature increase control is executed by uniformly controlling the amount of ignition timing retard at the start of the engine 10, the temperature of the GPF 44 after the temperature increase may vary. If the temperature of the GPF 44 after the temperature increase varies, there is a risk that the temperature of the GPF 44 becomes too high and affects the durability, or the temperature of the GPF 44 is insufficient and the regeneration efficiency decreases. The ECU 50 of this embodiment executes the temperature increase control at the start of the engine 10 as follows.

[0033] [Temperature increase control at engine start] FIG. 3 is a flowchart exemplifying the temperature increase control at the start of engine 10. This control is repeatedly executed while the ignition is on. ECU 50 determines whether there is a temperature increase request for GPF 44 at the start of engine 10 (step S1). If the answer in step S1 is No, this control ends.

[0034] If the answer in step S1 is Yes, ECU 50 determines whether it is a cold start (step S2). Specifically, if the temperature of the cooling water of engine 10 is less than a predetermined value, it is determined to be a cold start. If the answer in step S2 is Yes, ECU 50 executes temperature increase control with reference to the cold map (step S3). If the answer in step S2 is No, ECU 50 executes temperature increase control with reference to the warm map (step S4). Steps S3 and S4 are examples of the processes executed by the temperature increase control unit and the ignition retard amount control unit.

[0035] FIGS. 4A and 4B are diagrams exemplifying the cold map and the warm map that define the ignition retard amount, respectively. The horizontal axis indicates the engine speed, and the vertical axis indicates the in-cylinder air amount. The in-cylinder air amount is calculated based on the intake pressure, the valve timing of intake valve 36v and exhaust valve 37v, the rotational speed of engine 10, and the atmospheric pressure. The cold map and the warm map define the ignition retard amount corresponding to the engine speed and the in-cylinder air amount. The cold map and the warm map define the retard amount to be a smaller value as the engine speed is higher and as the in-cylinder air amount is larger. Here, the smaller the retard amount, the smaller the increase in the exhaust heat amount due to the retard process.

[0036] In the cold map, retard angles R1 to R3 are defined. Among the retard angles R1 to R3, the retard angle R1 is the minimum value and the retard angle R3 is the maximum value. Also, in the warm map, retard angles R1 to R4 are defined. Among the retard angles R1 to R4, the retard angle R4 is the maximum value. The retard angle R1 is set to zero, for example. The retard angles R1 to R3 in the cold map correspond to the retard angles R2 to R4 in the warm map. That is, under the same conditions of engine speed and in-cylinder air amount, the retard angle defined by the cold map is smaller than the retard angle defined by the warm map. As described above, in the case of cold start, the exhaust heat amount is higher than that in the case of warm start, and the GPF44 is likely to heat up. For this reason, the variation in the temperature of the GPF44 after heating is suppressed between the case of cold start and the case of warm start.

[0037] In the above embodiment, the retard angle is controlled using two maps. However, based on the temperature of the cooling water at the start of the engine 10, the retard angle may be controlled using three or more types of maps. Also, the retard angle is not limited to being controlled based on the maps as described above, and for example, it may be controlled based on an arithmetic expression using the engine speed and the in-cylinder air amount as arguments.

[0038] As described above, in addition to the engine 10, the hybrid vehicle 1 includes a motor 15 and a battery 16. For example, the battery 16 supplies power to the motor 15, which is a driving power source, and charges the regenerative power of the motor 15. For this reason, the battery 16 is heavier than the battery mounted on an engine vehicle. Thus, the weight of the hybrid vehicle 1 is greater compared to an engine vehicle. As a result, the load on the engine 10 in the hybrid driving mode is greater compared to the engine of an engine vehicle. For this reason, the amount of PM emissions in the hybrid driving mode may increase compared to an engine vehicle. For this reason, the content of the above embodiment is suitable for the hybrid vehicle 1.

[0039] The content of the above embodiment may also be applied to a control device for an engine vehicle having only an engine as a driving power source. The content of the above embodiment may also be applied to a control device for a hybrid vehicle in which an engine and a first motor are connected to a drive shaft connected to drive wheels via a planetary gear and a second motor is connected to the drive shaft.

[0040] As described above in detail with reference to the embodiments of the present invention, the present invention is not limited to such specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims.

Explanation of Signs

[0041] 1 Hybrid vehicle 10 Engine 15 Motor 16 Battery 18 Torque converter 20 Lock-up clutch 44 GPF (Filter) 50 ECU (Control device, Temperature rise control unit, Retard amount control unit)

Claims

1. An engine that is a driving power source, a filter that collects exhaust particulates from the engine, and a control device, wherein the control device includes a temperature increase control unit that raises the temperature of the filter by delaying the ignition timing of the engine, and a retard angle amount control unit that reduces the retard angle amount of the ignition timing at cold start of the engine compared to the retard angle amount of the ignition timing at warm start of the engine so as to suppress variations in the exhaust heat quantity of the engine due to the retard processing at cold start and warm start of the engine, wherein the retard angle amount control unit reduces the retard angle amount as the engine speed is higher, reduces the retard angle amount as the in-cylinder air quantity of the engine is larger, and under the same conditions of the engine speed and in-cylinder air quantity, reduces the retard angle amount of the ignition timing at cold start of the engine compared to the retard angle amount of the ignition timing at warm start of the engine, a vehicle.

2. A motor that is a driving power source, and a battery that exchanges electric power with the motor, the vehicle according to Claim 1.

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