JP2022044376A - vehicle - Google Patents

Abstract

To suppress vibration of a vehicle and suppress deterioration of fuel economy.SOLUTION: A vehicle comprises a controller that is configured to: when an accelerator pedal is off and a rotation speed of an internal combustion engine exceeds a return rotation speed higher than a target idle rotation speed at the time when the internal combustion engine is idled, control the internal combustion engine to perform fuel cut of stopping fuel injection in the internal combustion engine; and when the rotation speed of the internal combustion engine is equal to or less than the return rotation speed during the fuel cut, control the internal combustion engine so that the fuel injection in the internal combustion engine is started and idle operation is performed at the target idle rotation speed. The controller increases the target idle rotation speed and the return rotation speed when the vibration of the vehicle is likely to be higher than when the vibration of the vehicle is not likely to be higher.SELECTED DRAWING: Figure 2

Description

The present invention relates to a vehicle, and more particularly to a vehicle including an internal combustion engine.

Conventionally, as a vehicle of this type, a vehicle equipped with an internal combustion engine has been proposed (see, for example, Patent Document 1). In this device, when the accelerator pedal is off and the internal combustion engine rotation speed exceeds a predetermined rotation speed higher than the target idle rotation speed during idle operation (self-sustaining operation), fuel injection in the internal combustion engine is stopped. When the internal combustion engine speed drops below the return speed during the fuel cut, fuel injection is restarted (returning from the fuel cut) and idle operation of the internal combustion engine is started. .. As a result, the rapid increase (blow-up) in the rotation speed of the internal combustion engine when starting the idle operation of the internal combustion engine is suppressed.

Japanese Unexamined Patent Publication No. 2010-185315

In the above-mentioned vehicle, it is desired to increase the target idle rotation speed in order to suppress the vibration of the vehicle. However, when the target idle rotation speed is increased, the return rotation speed is also increased, and it is necessary to suppress the engine stall because the rotation speed of the internal combustion engine becomes lower than the target idle rotation speed when returning from the fuel cut. If the return speed is increased, fuel injection is restarted earlier than the fuel cut, resulting in lower fuel consumption. Therefore, it is recognized as an important issue to achieve both suppression of vehicle vibration and suppression of deterioration of fuel efficiency.

The main object of the vehicle of the present invention is to achieve both suppression of vibration of the vehicle and suppression of deterioration of fuel efficiency.

The vehicle of the present invention has adopted the following means in order to achieve the above-mentioned main object.

The vehicle of the present invention
With an internal combustion engine
When the accelerator pedal is off and the rotation speed of the internal combustion engine exceeds the return rotation speed higher than the target idle rotation speed when the internal combustion engine is idle, the fuel for stopping the fuel injection in the internal combustion engine is stopped. The internal combustion engine is controlled so that the cut is executed, and when the rotation speed of the internal combustion engine becomes equal to or lower than the return rotation speed during the execution of the fuel cut, fuel injection in the internal combustion engine is started and the said. A control device that controls the internal combustion engine so that it is operated idle at a target idle speed, and
It is a vehicle equipped with
The control device is
When the vibration of the vehicle is likely to be large, the gist is to increase the target idle speed and the return rotation speed as compared with the case where the vibration of the vehicle is unlikely to be large.

In the vehicle of the present invention, when the vibration of the vehicle is likely to be large, the target idle rotation speed and the return rotation speed are increased as compared with the case where the vibration of the vehicle is not likely to be large. This makes it possible to suppress the vibration of the vehicle when starting fuel injection. In addition, when the vibration of the vehicle is not likely to be large, the target idle speed and the return rotation speed are lowered as compared with the case where the vibration of the vehicle is likely to be large, so that the fuel injection in the internal combustion engine is started. Can be delayed, and the decrease in fuel consumption can be suppressed. As a result, it is possible to achieve both suppression of vehicle vibration and suppression of deterioration of fuel efficiency.

In such a vehicle of the present invention, an automatic transmission whose output shaft is connected to a drive shaft connected to an axle, a turbine runner connected to an input shaft of the automatic transmission, and a clutch shaft of the internal combustion engine are connected. A torque converter having a pump impeller, a turbine runner, and a lockup clutch capable of connecting and disconnecting the pump impeller, and being connected to the crank shaft via the first clutch and via the second clutch. The control device includes a gear mechanism connected to the drive, and the control device travels with the first and second clutches turned on and the first drive mode in which the first and second clutches are turned off. The engine, the automatic transmission, the lockup clutch, and the first and second clutches are controlled so as to switch between the second drive mode and the second drive mode, and the vibration of the vehicle may increase. As an occasion, when the lockup clutch is off, when the vehicle is traveling in the second drive mode, or when the rotation speed of the internal combustion engine is equal to or less than a predetermined rotation speed may be mentioned. By doing so, the vibration of the vehicle can be suppressed at a more appropriate timing.

It is a block diagram which shows the outline of the structure of the automobile 20 as an Example of this invention. It is a flowchart which shows an example of the setting routine executed by the CPU (not shown) of the ECU 50. Vehicle speed V and each rotation speed (engine 22 rotation speed Ne, input shaft 32 rotation speed (turbine rotation speed), target idle rotation speed Nidl *, return rotation speed Nre) from the start to the stop of the automobile 20. ), The state of the torque converter 28, and an explanatory diagram showing an example of time change with or without execution of fuel cut.

Next, an embodiment for carrying out the present invention will be described with reference to examples.

FIG. 1 is a configuration diagram showing an outline of the configuration of an automobile 20 as an embodiment of the present invention. As shown in the figure, the automobile 20 of the embodiment includes an engine 22, a torque converter 28, a forward / backward switching mechanism 29, a transmission 30, a gear mechanism 36, and an electronic control unit (hereinafter referred to as “ECU”) 50. And.

The engine 22 is an internal combustion engine that outputs power from a hydrocarbon-based fuel such as gasoline or light oil, and fuel injection control, ignition control, and intake air are controlled by an ECU 50 that inputs signals from various sensors that detect the operating state of the engine 22. It receives operation control such as amount adjustment control.

The torque converter 28 is configured as a fluid torque converter with a lockup clutch, and amplifies and transmits the power of the crankshaft 23 of the engine 22 to the input shaft 32 of the transmission 30 or amplifies the torque. It can be transmitted as it is without any problems. The torque converter 28 includes a pump impeller connected to the crankshaft 23 of the engine 22, a turbine runner connected to the input shaft 32, and a hydraulically driven lockup clutch 28a capable of connecting the pump impeller and the turbine runner. Be prepared. The lockup clutch 28a is driven and controlled by the ECU 50.

The forward / backward switching mechanism 29 includes a sun gear 29S, a ring gear 29R, first and second pinion gears 29P1 and 29P2, a carrier 29C, a clutch C1, and a brake B1. The sun gear 29S meshes with the drive gear 360 of the gear mechanism 36. The carrier 29C is connected to the input shaft 32 of the transmission 30. The clutch C1 connects and disconnects the carrier 29C and the gear mechanism 36. The brake B1 allows or prohibits rotation of the ring gear 29R. The clutch C1 and the brake B1 are driven by hydraulic pressure from a hydraulic circuit (not shown). As a result, by disengaging the brake B1 and the clutch C1, the power transmitted from the torque converter 28 to the input shaft 32 can be directly transmitted to the primary pulley of the transmission 30 to advance the vehicle. Further, by turning on the brake B1 and disengaging the clutch C1, the rotation of the input shaft 32 is converted in the reverse direction and transmitted to the primary pulley of the transmission 30, so that the vehicle can be moved backward. Further, by disengaging the brake B1 and turning on the clutch C1, the power transmitted from the torque converter 28 to the input shaft 32 can be transmitted to the gear mechanism 36.

The transmission 30 is configured as a belt-type continuously variable transmission (CVT), and has a variable groove width and a primary pulley connected to an input shaft 32 (input shaft), and a groove width can be changed and is output. It includes a secondary pulley connected to the shaft 31, a belt hung in the grooves of the primary pulley and the secondary pulley, and a hydraulic circuit for changing the groove widths of the primary pulley and the secondary pulley using hydraulic oil. The transmission 30 drives the hydraulic circuit to change the groove widths of the primary pulley and the secondary pulley, so that the power of the input shaft 32 (input shaft) is steplessly changed and output to the output shaft 31. The output shaft 31 is connected to the drive shaft 37 via the clutch C2. As a result, by turning on the clutch C2, the output shaft 31 and the drive shaft 37 are connected, and the power output to the output shaft 31 can be transmitted to the drive shaft 37. Then, by disengaging the clutch C2, the connection between the output shaft 31 and the drive shaft 37 is released.

The gear mechanism 36 includes a drive gear 360 and a counter gear mechanism 362. The drive gear 360 meshes with the sun gear 29S of the forward / backward switching mechanism 29. The counter gear mechanism 362 connects the counter-driven gear that meshes with the drive gear 360, the counter shaft 364 that rotates integrally with the counter-driven gear, the gear that transmits the rotation of the counter shaft 364 to the drive shaft 37, and the counter shaft 364 and the counter-driven gear. And a synchro mechanism 366 for disconnecting the connection. The synchro mechanism 366 is driven by hydraulic pressure from a hydraulic circuit (not shown). As a result, by turning on the clutch C1 of the forward / backward switching mechanism 29 and turning on the synchro mechanism 366, the input shaft 32 and the drive shaft 37 are connected via the gear mechanism 36, and the power transmitted to the input shaft 32 is transmitted. It is transmitted to the drive shaft 37 via the gear mechanism 36. Further, the connection between the input shaft 32 and the drive shaft 37 is released by disengaging the clutch C1 of the forward / backward switching mechanism 29 and disengaging the synchro mechanism 366.

Although not shown, the ECU 50 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. ..

Signals from various sensors necessary for the operation control of the engine 22, the lockup clutch 28a, and the control of the transmission 30 are input to the ECU 50 via the input port. The signals input to the ECU 50 include, for example, the crank angle θcr from the crank position sensor 22a that detects the rotational position of the crankshaft 23 of the engine 22, and the cooling water temperature from the water temperature sensor that detects the temperature of the cooling water of the engine 22. Can be mentioned. The throttle opening from the throttle position sensor that detects the position of the throttle valve and the intake air amount Qa from the air flow meter attached to the intake port can also be mentioned. The rotation speed Ni of the input shaft 32 from the rotation speed sensor attached to the input shaft 32 is input via the input port. Further, the ignition signal from the ignition switch 60 and the shift position SP from the shift position sensor 62 that detects the operation position of the shift lever 61 can also be mentioned. Further, the accelerator opening Acc from the accelerator pedal position sensor 64 that detects the depression amount of the accelerator pedal 63, the brake pedal position BP from the brake pedal position sensor 66 that detects the depression amount of the brake pedal 65, and the vehicle speed sensor 68. The vehicle speed V can also be mentioned.

From the ECU 50, various control signals necessary for controlling the operation of the engine 22 and the lockup clutch 28a28a of the torque converter 28, the forward / backward switching mechanism 29, the transmission 30, and the gear mechanism 36 are output via the output port. Examples of various control signals include a drive signal to a throttle motor for adjusting the throttle opening degree and a fuel injection valve. Further, a control signal for the lockup clutch 28a28a of the torque converter 28, a control signal for the clutch C1 of the forward / backward switching mechanism 29, a control signal for the hydraulic circuit of the brake B1, a control signal for the hydraulic circuit of the transmission 30, and a gear mechanism 36. A control signal to the hydraulic circuit of the synchro mechanism 366 can be mentioned.

The ECU 50 calculates the rotation speed Ne of the engine 22 based on the crank angle θcr from the crank position sensor 22a. The ECU 50 has a load factor (ratio of the volume of air actually sucked 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 and the rotation speed Ne of the engine 22. KL is calculated.

In the automobile 20 of the embodiment configured in this way, the belt drive mode (first drive mode) in which the vehicle travels while outputting the power from the engine 22 to the drive shaft 37 via the transmission 30 and the power from the engine 22 are changed. The vehicle travels by switching between a gear drive mode (second drive mode) in which the vehicle travels while being output to the drive shaft 37 via the gear mechanism 36 without going through the machine 30. In the belt drive mode, the clutch C1 of the forward / backward switching mechanism 29 is turned off, the clutch C2 is turned on, and the synchro mechanism 366 is turned off. In the gear drive mode, the clutch C1 of the forward / backward switching mechanism 29 is turned on, the clutch C2 is disengaged, and the synchro mechanism 366 is turned on. The automobile 20 runs in the gear start mode from the time of starting until the load factor KL of the engine 22 exceeds the predetermined factor KLref. Then, after the load factor KL of the engine 22 exceeds the predetermined factor KLref, the engine 22 travels in the belt drive mode.

Further, in the automobile 20 of the embodiment, when a predetermined lockup condition is satisfied after starting, the lockup clutch 28a is turned on, the pump impeller of the torque converter 28 and the turbine runner are directly connected, and the power from the engine 22 is obtained. Is mechanically and directly transmitted to the input shaft 41. The predetermined lockup condition is within the lockup vehicle speed range, and the rotation speed Ne of the engine 22 and the rotation speed (turbine rotation speed) of the input shaft 32 may be less than a certain value.

In the automobile 20 of the embodiment, when the accelerator pedal 63 is off and the rotation speed Ne of the engine 22 exceeds the return rotation speed Nre, the engine is executed so that the fuel injection for stopping the fuel injection in the engine 22 is executed. 22 is controlled. Then, when the rotation speed Ne of the engine 22 becomes equal to or less than the return rotation speed Nre during the execution of the fuel cut, the fuel injection in the engine 22 is started (returning from the fuel cut) at the target idle rotation speed Nidl *. The engine 22 is controlled so as to be idle-operated (self-sustaining operation). The return rotation speed Nre is set to be higher than the target idle rotation speed Nidl *. This is to prevent the engine from stalling when the engine 22 speed Ne becomes lower than the target idle speed Nidl * when returning from the fuel cut. Details of the target idle rotation speed Nidl * and the return rotation speed Nre will be described later.

Next, the operation of the automobile 20 of the embodiment configured in this way, particularly the operation when setting the target idle rotation speed Nidl * and the return rotation speed Nre will be described. FIG. 2 is a flowchart showing an example of a setting routine executed by a CPU (not shown) of the ECU 50. This routine is repeatedly executed every predetermined time (for example, several msec).

When this routine is executed, the CPU of the ECU 50 determines whether or not the vibration of the vehicle may increase (step S100). This determination determines that the vibration of the vehicle may increase when the lockup clutch 28a is off or in the gear drive mode, or when the rotation speed Ne of the engine 22 is a predetermined rotation speed Nref or less. Here, the predetermined rotation speed Nref is set higher than the region where the vehicle vibrates during deceleration, and is set to, for example, 850 rpm, 900 rpm, 950 rpm, or the like. When the lockup clutch 28a is off and the gear drive mode is set and the rotation speed Ne of the engine 22 is equal to or less than the predetermined rotation speed Nref, the vehicle is immediately after the vehicle starts or just before the stop, and the gear drive mode and the belt drive mode are used. There is a high possibility that the clutch C1 will be turned on and off in order to switch between the two. When the clutch C1 is transitioning from engagement to disengagement or from disengagement to engagement, idle operation of the engine 22 at a low rotation speed may increase vibration. Therefore, by determining whether the lockup clutch 28a is off, the gear drive mode is set, and the rotation speed Ne of the engine 22 is equal to or less than the predetermined rotation speed Nref, is there a possibility that the vibration of the vehicle becomes large? It can be determined whether or not.

When there is a possibility that the vibration of the vehicle becomes large in step S100, the target idle rotation speed Nidl * is set to the first idle rotation speed Ni1 and the return rotation speed Nre is set to the first return rotation speed Nre1 (step S110). ), End this routine. The first idle rotation speed Ni1 is a rotation speed predetermined as a rotation speed higher than the upper limit of the resonance rotation speed band in which resonance occurs in the vehicle when the engine 22 is idle, and is set to, for example, 830 rpm, 840 rpm, 850 rpm, or the like. Will be done. The first return rotation speed Nre1 is higher than the first idle rotation speed Ni1 and is set to 1150 rpm, 1200 rpm, 1250 rpm, or the like. When the target idle rotation speed Nidl * and the return rotation speed Nre are set in this way, the ECU 50 determines that the fuel in the engine 22 when the rotation speed Ne of the engine 22 exceeds the return rotation speed Nre when the accelerator pedal 63 is off. The engine 22 is controlled so that the fuel cut for stopping the injection is executed. Then, when the rotation speed Ne of the engine 22 becomes equal to or less than the return rotation speed Nre during the execution of the fuel cut, the fuel injection in the engine 22 is started (returning from the fuel cut) at the target idle rotation speed Nidl *. The engine 22 is controlled so as to be idle-operated (self-sustaining operation).

When there is no possibility that the vibration of the vehicle becomes large in step S100, the target idle rotation speed Nidl * is set to the second idle rotation speed Ni2, and the return rotation speed Nre is set to the second return rotation speed Nre2 (step S120). ), End this routine. The second idle rotation speed Ni2 is the same as the lower limit rotation speed of the resonance rotation speed band, or lower than the lower limit rotation speed, and is set as the rotation speed at which the engine 22 can be efficiently idle-operated. The second idle rotation speed Ni2 is lower than the first idle rotation speed Ni1, and is set to, for example, 780 rpm, 790 rpm, 800 rpm, or the like. The second return rotation speed Nre2 is higher than the second idle rotation speed Ni2 and lower than the first return rotation speed Nre1, and is set to, for example, 840 rpm, 850 tpm, 860 rpm, or the like. When the target idle rotation speed Nidl * and the return rotation speed Nre are set in this way, the ECU 50 determines that the fuel in the engine 22 when the rotation speed Ne of the engine 22 exceeds the return rotation speed Nre when the accelerator pedal 63 is off. The engine 22 is controlled so that the fuel cut for stopping the injection is executed. Then, when the rotation speed Ne of the engine 22 becomes equal to or less than the return rotation speed Nre during the execution of the fuel cut, the fuel injection in the engine 22 is started (returning from the fuel cut) at the target idle rotation speed Nidl *. The engine 22 is controlled so as to be idle-operated (self-sustaining operation).

FIG. 3 shows the vehicle speed V from the start to the stop of the automobile 20, each rotation speed (rotational speed Ne of the engine 22, rotation speed of the input shaft 32 (turbine rotation speed), target idle rotation speed Nidl *, It is explanatory drawing which shows an example of the time change of the return rotation speed Nre), the state of a torque converter 28, and the presence or absence of execution of a fuel cut. A comparative example in which the target idle rotation speed Nidl * and the return rotation speed Nre are constant values is shown by a broken line regardless of whether or not the vibration of the vehicle may increase in the time change of each rotation speed.

When the accelerator pedal 63 is turned on while the engine 22 is idle-operated and stopped, the engine 22 starts load operation in the gear drive mode, and the vehicle speed V increases. In the torque converter 28, the lockup clutch 28a is turned off when the engine 22 is idle and stopped, but when the torque from the engine 22 becomes large and slip occurs, the lockup clutch 28a is turned on. Is done (time t1). When the lockup clutch 28a is off in the gear drive mode, there is a high possibility that the clutch C1 will be turned off in order to switch from the gear drive mode to the belt drive mode, and the rotation speed Ne of the engine 22 enters the resonance rotation speed band. If the engine 22 is idle-operated at a low rotation speed, the vibration may increase. In the embodiment, since the target idle rotation speed Nidl * is set to the first idle rotation speed Ni1 higher than the upper limit rotation speed of the resonance rotation speed band, the vibration of the vehicle can be suppressed.

When the lockup clutch 28a is turned on, the running in the gear drive mode is switched to the running in the belt drive mode, and the engine 22 is operated at a low rotation speed such that the rotation speed Ne of the engine 22 falls into the resonance rotation speed band. It is considered unlikely that the vibration of the vehicle will increase even if the vehicle is idle. In the embodiment, when the lockup clutch 28a is turned on, the target idle rotation speed Nidl * is set to the second idle rotation speed Ni2 and the return rotation speed Nre is set to the second return rotation speed Nre2. Compared with the case where the idle rotation speed Nidl * is set to the first idle rotation speed Ni1, it is possible to improve the fuel efficiency when the engine 22 is idle-operated.

When the accelerator pedal 63 is turned off (time t2), the fuel cut of the engine 22 is executed, and the vehicle speed V and the rotation speed Ne of the engine 22 decrease. Then, when the rotation speed Ne of the engine 22 becomes equal to or less than the return rotation speed Nre (time t4), the engine 22 returns from the fuel cut and starts idle operation of the engine 22. Since the return rotation speed Nre is set to the second return rotation speed Nre2 until the lockup clutch 28a is turned off after switching from the belt drive mode to the gear drive mode, the return rotation speed Nre is higher than the second return rotation speed Nre2. It is possible to delay the recovery from the fuel cut of the engine 22 as compared with the comparative example (the recovery timing from the fuel cut is time t3) maintained by the rotation speed. This makes it possible to improve fuel efficiency.

Immediately after the lockup clutch 28a is turned off and the clutch C1 switched from the belt drive mode to the gear drive mode is turned on, the vibration of the vehicle tends to increase. In the embodiment, when the lockup clutch 28a is turned off and the belt drive mode is switched to the gear drive mode, the target idle rotation speed Nidl * is set to the first idle rotation speed Ni1, so that the vibration of the vehicle can be suppressed. Therefore, it is possible to achieve both suppression of vehicle vibration and suppression of deterioration of fuel efficiency.

According to the automobile 20 of the embodiment described above, when the vibration of the vehicle is likely to be large, the target idle speed and the return rotation speed are set higher than when the vibration of the vehicle is not likely to be large. By doing so, it is possible to achieve both suppression of vehicle vibration and suppression of deterioration of fuel efficiency.

The automobile 20 of the embodiment is provided with a gear mechanism 36, and is capable of traveling in a belt drive mode and a gear drive mode. However, it may be possible to travel only in the belt drive mode without providing the gear mechanism 36.

In the automobile 20 of the embodiment, the CVT is used as the transmission 30, but a multi-speed transmission may be used.

In the examples, the case where the present invention is applied to an automobile is illustrated. However, the present invention may be applied to other vehicles such as trains and machine tools.

The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem will be described. In the embodiment, the engine 22 corresponds to the "internal combustion engine" and the ECU 50 corresponds to the "control device".

As for the correspondence between the main elements of the examples and the main elements of the invention described in the column of means for solving the problem, the invention described in the column of means for solving the problems of the examples is carried out. Since it is an example for specifically explaining the form for solving the problem, the elements of the invention described in the column of means for solving the problem are not limited. That is, the interpretation of the invention described in the column of means for solving the problem should be performed based on the description in the column, and the examples are the inventions described in the column of means for solving the problem. It is just a concrete example.

Although the embodiments for carrying out the present invention have been described above with reference to the embodiments, the present invention is not limited to these embodiments and may be in various embodiments within the scope of the gist of the present invention. Of course it can be done.

The present invention can be used in the vehicle manufacturing industry and the like.

20 Automobile, 22 Engine, 22a Crank Position Sensor, 23 Crank Shaft, 28 Torque Converter, 28a Lockup Clutch, 29 Forward / Forward Switching Mechanism, 29C Carrier, 29P1 1st Pinion Gear, 29P2 2nd Pinion Gear, 29R Ring Gear, 29S Sun Gear, 30 Transmission, 31 output shaft, 32 input shaft, 36 gear mechanism, 37 drive shaft, 50 ECU, 60 ignition switch, 61 shift lever, 62 shift position sensor, 63 accelerator pedal, 64 accelerator pedal position sensor, 65 brake pedal, 66 Brake pedal position sensor, 68 vehicle speed sensor, 360 drive gear, 362 counter gear mechanism, 364 counter shaft, 366 sync mechanism, B1 brake, C1, C2 clutch.

Claims (1)

With an internal combustion engine
When the accelerator pedal is off and the rotation speed of the internal combustion engine exceeds the return rotation speed higher than the target idle rotation speed when the internal combustion engine is idle, the fuel for stopping the fuel injection in the internal combustion engine is stopped. The internal combustion engine is controlled so that the cut is executed, and when the rotation speed of the internal combustion engine becomes equal to or lower than the return rotation speed during the execution of the fuel cut, fuel injection in the internal combustion engine is started and the said. A control device that controls the internal combustion engine so that it is operated idle at a target idle speed, and
It is a vehicle equipped with
The control device is
A vehicle in which the target idle speed and the return rotation speed are increased when the vibration of the vehicle is likely to be large, as compared with the case where the vibration of the vehicle is not likely to be large.

Images