JPH0816453B2 - Mechanical supercharger control device for internal combustion engine for vehicle - Google Patents

Description

The present invention relates to a supercharging pressure control device for a vehicle internal combustion engine having a mechanical supercharger.

[Conventional technology]

It has been proposed that a mechanical supercharger is provided in the intake pipe to improve the output of the internal combustion engine. The mechanical supercharger is usually connected to the crankshaft of the engine via a clutch, and the clutch is adapted to be engaged or disengaged depending on the load. That is, when the load is high, the clutch is engaged and the supercharger operates to perform supercharging, and when the load is light, the clutch is released to stop the supercharger and the supercharging is not performed.

[Problems to be solved by the invention]

When the gear ratio of the transmission is high (for example, low or second, while running), even a slight change in the intake air amount causes a large torque change on the output side of the transmission. And
The torque change on the output side has a greater effect when the load is higher because the engine torque itself is larger. Therefore, it is preferable that the threshold value of the load at the time of switching from the non-supercharging state to the supercharging state is low in the state of the high gear ratio in order to reduce the shock. However, when the load threshold is set low in this way, the fuel consumption rate deteriorates because the supercharger is operated from an unnecessarily low load.

An object of the present invention is to prevent a switching shock in a driving range in which the gear ratio of a vehicle is high and to prevent the fuel consumption rate from deteriorating.

Incidentally, as a related technique, it is a facial wash, but the actual application is Sho 61-3640.
No., Jitsugan Sho 61-8966.

[Means for solving problems]

In FIG. 1, the internal combustion engine includes a supercharger 2 in an intake pipe 1. The supercharging control device of the present invention comprises means 3 for detecting a load state factor of an internal combustion engine, means 4 for detecting a gear ratio of a transmission, and a load threshold for switching the supercharger between operation and stop. A supercharger operating range setting means 5 for setting the transmission gear ratio to be low when the gear ratio of the transmission detected by the gear ratio detection means is high, and to be high when the gear ratio of the transmission detected by the gear ratio detection means is low. , A supercharger operating means 6 for selectively operating the supercharger 2 by comparing a load threshold set by the supercharger operating range setting means 5 with an actual load detected by the load factor detecting means. To be done.

[Work]

The gear ratio detecting means 4 detects the gear ratio of the transmission, and the supercharger working range setting means 5 sets a low load threshold when the gear ratio is high and a high load threshold when the gear ratio is low. The supercharger operating means 6 compares this load threshold with the actual load detected by the load detecting means 3 to drive or stop the supercharger 2.

〔Example〕

FIG. 2 shows the overall configuration of the embodiment. 10 is a cylinder block, 11 is a piston, 12 is a connecting rod, 13 is a crankshaft, 14 is a combustion chamber, 15 is a cylinder head, 16 is an intake valve, 17 is an intake port, 18 is an exhaust valve, 19 is an exhaust port. . The intake port 17 is connected to the throttle body 25 via an intake pipe 20 and a mechanical supercharger 22. Throttle body
A throttle valve 24 is arranged inside 23, and an air flow meter 25 and an air cleaner 26 are located upstream thereof.

The mechanical supercharger 22 is a roots pump in this embodiment, and is provided with a pair of rotors 31 and 32, and the rotors 31 and 32 rotate with respect to the housing 29 while maintaining a minute gap to perform compression operation. Be seen. A pulley 33 is provided on a rotary shaft 32A of one rotor 32 of the pair of rotors via a clutch mechanism 34, and the pulley 33 is connected to a pulley 36 on the crankshaft 16 via a belt 35.

A bypass passage 41 is arranged so as to bypass the supercharger 22, one end of the bypass passage 41 is connected to an intake pipe 23 upstream of the supercharger 22 downstream of the throttle valve 24, and
The other end of 41 is connected to the intake pipe 20 downstream of the supercharger 22. A bypass control valve 42 is arranged in the bypass passage 41. The bypass control valve 42 is a diaphragm drive type, and the diaphragm
It is connected to 43 and is opened and closed according to the pressure applied to the diaphragm 43. The diaphragm 43 is switched by an electromagnetic three-way valve 44 between an intake pipe negative pressure port 45 downstream of the throttle valve 24 and an atmospheric pressure port 46 upstream. Solenoid valve 44 demagnetized (OF
When F), the diaphragm 43 communicates with the negative pressure port 45, and when excited (ON), communicates with the atmospheric pressure port 46. A delay element 47 is arranged between the solenoid valve 44 and the negative pressure port 45. The delay element 47 is composed of an orifice 47a and a check valve 47b which are arranged in parallel.

A control circuit 50 controls the operation of the clutch 34 and the solenoid valve 44, and is configured as a microcomputer system. The control circuit 50 is a microprocessing unit (MP
U) 51, memory 52, input port 53, output port 54
And a bus 55 interconnecting them. A signal from each sensor is input to the input port 53. A signal relating to the intake air amount Q is obtained from the air flow meter 25. Further, the rotation speed sensor 61 obtains a signal related to the rotation speed NE of the crankshaft 13. Reference numeral 62 is a throttle sensor, and a signal TA corresponding to the opening degree of the throttle valve 24 is obtained. Further, the gear position sensor 63 generates different signals depending on whether the gear ratio of the transmission (not shown) is low or high. A drive signal is sent from the output port 54 to the clutch 34 and the solenoid valve 44 according to the control program stored in the memory 52.

FIG. 3 shows a flow chart of a routine for controlling the drive of the clutch 34 according to the present invention. It goes without saying that a program that implements this flowchart is stored in the non-volatile area of the memory 52. The routine shown in FIG. 3 is a time interruption routine that is executed every 100 msec. In step 99, the gear position sensor 63
Based on the signal from, it is determined whether the gear ratio of the transmission is high, that is, whether it is low or second running. When the gear ratio is high, the routine proceeds from step 99 to step 100. In step 100, it is determined whether the ratio of the intake air amount Q to the engine speed NE is larger than a predetermined value (for example, 0.4 / rev: see FIG. 4 (a)). This predetermined value is a threshold value when the supercharger is switched from stop to operation. When Q / NE> 0.4, the routine proceeds from step 100 to step 104, and the counter C is cleared. This counter C is a software counter that measures the elapsed time after the clutch 34 is switched from the engagement condition to the release condition, as will be described later. In the next step 106, a command to excite the clutch 34 is issued from the output port 54, and when the clutch 34 is engaged, the rotation of the crankshaft 13 is rotated by the supercharger 22 via the pulley 36, the belt 35 and the pulley 33. The rotors 31 and 32 are rotated by the rotation of the rotor 31 and 32. In step 107, the solenoid valve 44 is excited and the diaphragm 43 is communicated with the atmospheric pressure port 46. Therefore, the spring 49 closes the bypass control valve 42 via the diaphragm 43. Thus, the bypass passage 41 is closed and the air from the supercharger 22 is introduced into the engine without being bypassed. Therefore, supercharging will be executed. Q / NE = 0.4, which is the load threshold in step 100, is the clutch in low gear running (high gear ratio running) where switching shock is likely to occur.
It is set to an appropriate value so that shock does not occur even if 34 is engaged and the supercharger is rotated.

When Q / NE ≦ 0.4 in the high gear ratio state, the routine proceeds from step 100 to step 108, where it is judged whether or not the counter C ≧ C ₁ . When the time determined by the predetermined value C ₁ , for example, 10 seconds, has not elapsed since the transition from the supercharger operating condition to the supercharger stop condition, the process proceeds to step 109, the counter C is incremented, and in step 110, the clutch 34 Is maintained. In step 111, the solenoid valve 44 is demagnetized.
Therefore, the diaphragm 43 is communicated with the intake pipe negative pressure port 45 side, and the bypass control valve 42 is connected by the negative pressure of the intake port 45.
Is in the valve open position, and the bypass passage 41 is open. Therefore, supercharging is weakened. Here, the delay from the shift to the non-supercharging condition until the supercharger is actually stopped is due to the frequent overshoot of the clutch 34 due to the overshoot of the measured value of the air flow meter 25 accompanying the temporary return of the throttle valve. This is to prevent repeated engagement and disengagement and improve the durability of the clutch 34.

When C ≧ C _{1 in} step 108, that is, when 10 seconds have elapsed from the start of shifting to the non-supercharging condition, the routine proceeds from step 108 to step 114, and the clutch 34 is released. Therefore, the supercharger 22 is separated from the crankshaft 16, and the driving of the supercharger is stopped. Next, the routine proceeds to step 107, where the solenoid valve 44 is excited again, and atmospheric pressure acts on the diaphragm 43, so that the bypass control valve 42 is closed again. This is the bypass passage
The closure of 41 allows air to pass through the supercharger 22 and
By increasing the idling speed of 2 to speed up the rotation of the supercharger during the next acceleration operation, the acceleration performance is improved.

When the gear ratio is low (third or top gear running), the routine proceeds from step 99 to step 118, where the intake air amount-rotation speed ratio Q / NE is the supercharging condition and the specific supercharging condition when the gear ratio is low. It is determined whether or not the load threshold value for switching is greater than, for example, 0.5 (/ rev: see FIG. 4B). If the load threshold value is too high, switching shock will occur, and if it is too low, the fuel consumption rate will deteriorate. Therefore, both are set in harmony. Q / NE> 0.5 (/ re
In the case of v), the routine proceeds from step 118 to step 120, and the counter C is cleared. In the next step 122, the clutch 34 is engaged, and in step 124 the throttle valve opening TA
It is determined whether the change rate ΔTA of is larger than a predetermined value, for example, 1.46 ° / 16 ms. At the time of sudden acceleration, the routine proceeds to step 126, where the solenoid valve 44 is excited, so the bypass control valve 42 is closed, and full supercharging is immediately performed. On the other hand, at the time of gentle acceleration, the routine proceeds to step 128, where the solenoid valve 44 is demagnetized. At this time, the diaphragm 43 communicates with the negative pressure port 45, but since this port 45 is a region where the intake air amount-rotation speed ratio is large, it is almost atmospheric pressure, and this atmospheric pressure is a supercharging condition. Is gradually transmitted through the orifice 47a. for that reason,
The bypass control valve 42 is gradually closed, and since the gear ratio is low, the impact at the start of supercharging is small as a whole. It

When Q / NE ≦ 0.5 (/ rev) in a low gear ratio state, the routine proceeds from step 118 to step 130, where it is determined whether or not the counter C ≧ C ₂ . If the time determined by the predetermined value C ₂ , for example, 5 seconds, has not elapsed since the transition from the supercharger operating condition to the supercharger stop condition, the process proceeds to step 132, and the counter C
Is incremented and the engagement of the clutch 34 is maintained in step 134. In step 111, the solenoid valve 44 is demagnetized. Therefore, the bypass control valve 42 is in the closed position and the bypass passage 41 is open. In the same manner as described above, a delay is provided between the shift to the non-supercharging condition and the actual release of the clutch 34 to prevent the clutch from being released due to the temporary return of the throttle valve, and to improve the durability of the clutch 34. Can be raised.

When C ≧ C _{2 in} step 130, that is, when 5 seconds, which is the delay time from the start of shifting to the non-supercharging condition in the state of low gear ratio, has elapsed, the process proceeds from step 130 to step 138, and the clutch 114 is released. To be done. Then proceed to step 128 Solenoid valve
44 is demagnetized and the bypass control valve 42 is opened.

Figure 5 shows high gear ratio running (low or second gear running)
FIG. 6 is a diagram for explaining the operation of the present invention in FIG. When acceleration starts at time t ₁ and Q / NE exceeds the threshold value 0.4 at time t ₂ , clutch 34 is engaged and supercharging is started. Intake air amount at time t ₃ −
When the rotation speed ratio becomes equal to or less than the threshold value, the solenoid valve 44 is demagnetized, and when the counter C = C ₁ , that is, after 10 seconds (t ₄ ), the clutch is released, and at the same time, the solenoid valve 44 is excited (ON).

FIG. 6 explains the operation in low gear ratio running (third or top running). The acceleration is started at time ₅ , and the clutch is engaged when the intake air amount-rotational speed ratio Q / NE exceeds the threshold value 0.5 at time t ₆ . Then, in the case of rapid acceleration (ΔTA> 1.46) (t _{6 to} t ₇ ), the solenoid valve 44 is excited (ON). Time t ₈ in the intake air quantity - the rotation speed ratio Q / NE starts incrementing the counter becomes below the map value, at the C _2, that is, after five seconds the clutch is released.

〔The invention's effect〕

According to the present invention, the threshold value of the load that determines the supercharging range is set to be lower when the shock with a high gear ratio is likely to occur than when the shock with a low gear ratio is less likely to occur. Since it enters from the load side, the influence of torque increase due to supercharging is reduced, and it is possible to prevent a shock from occurring when entering the turbocharger operating range.

Further, at a low gear ratio where a shock is unlikely to occur, the fuel consumption rate can be increased by increasing the load threshold value that determines the supercharging range, and these requirements can be harmonized. Furthermore, as an effect of the embodiment, as for the occurrence of impact during the slow acceleration operation under the same environmental conditions, which is accompanied by the transition to the supercharging condition in the traveling range of the low gear ratio at the high load threshold, By gradually closing the bypass control valve 42 by the delay device 47 in the region, such impact can be suppressed.

[Brief description of drawings]

FIG. 1 is a block diagram of the present invention. FIG. 2 is a schematic view of the entire configuration of the present invention. FIG. 3 is a flow chart for explaining the control operation of the present invention. FIG. 4 is a diagram for explaining how the setting of the supercharging state and the non-supercharging state in the present invention is changed by the gear ratio. FIG. 5 is an operation timing chart of the invention in a region where the gear ratio is high. FIG. 6 is an operation timing chart of the present invention in a region where the gear ratio is low. 13 …… Crankshaft, 22 …… Supercharger, 24 …… Throttle valve, 25 …… Air flow meter, 34 …… Clutch, 41 …… Bypass passage, 42 …… Bypass control valve, 44 …… Solenoid valve, 47 ... delay device, 50 ... control circuit, 61 ... engine speed sensor, 63 ... gear position sensor.

Front Page Continuation (72) Inventor Takuya Oyama 1 Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Co., Ltd. (72) Inventor Hidemi Onaka 1 Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Co., Ltd. (56) References Japanese Patent Laid-Open No. 61-25917 (JP, A)

Claims (1)

[Claims] 1. A vehicle internal combustion engine having a mechanical supercharger in an intake pipe, means for detecting a load state factor of the internal combustion engine, means for detecting a gear ratio of a transmission, and operation and stop of the supercharger. The load threshold value to be switched between and is set to be low when the gear ratio of the transmission detected by the gear ratio detection means is low and high when the gear ratio of the transmission detected by the gear ratio detection means is high. A turbocharger for selectively operating the turbocharger by comparing the threshold value of the load set by the turbocharger operating range determination means and the actual load detected by the load factor detection means. A mechanical supercharger control device for an internal combustion engine, which comprises an operating means.