JPH0988620A - Internal combustion engine with supercharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal combustion engine with a supercharger that can attain energy saving by recovering energy of exhaust gas in the case of the speed of the internal combustion engine being high. SOLUTION: An exhaust turbine 141 and a compressor 142 are uniaxially connected to constitute a supercharger. The supercharger and a crankshaft 111 of an internal combustion engine 11 are connected by continuously variable transmissions 146, 147, 148 and speed increasing gears 144, 145, but the change gear ratios of the continuously variable transmissions are controlled by a control part 15. In an operating state with excessive supercharging pressure, the output torque of the supercharger is transmitted to the internal combustion engine to recover the energy of exhaust gas. In an operating state with a turbine rotated at low speed, on the other hand, the compressor is driven by the internal combustion engine to improve accelerating sensation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a supercharged internal combustion engine, and more particularly to a supercharged internal combustion engine capable of recovering exhaust gas energy when the supercharging pressure is excessive.

[0002]

2. Description of the Related Art It is known to install a supercharger (turbocharger or supercharger) in an internal combustion engine in order to increase the output of the internal combustion engine without increasing the displacement of the internal combustion engine. Among them, the turbocharger drives a turbine by exhaust gas discharged from the internal combustion engine, and supercharges intake air by a compressor mechanically directly connected to the turbine, thereby increasing the output of the internal combustion engine.

However, since the drive source of the turbocharger is exhaust gas, it is necessary to avoid a delay in the acceleration of the compressor when the engine speed is low and the deterioration of the response during acceleration. I couldn't. In order to solve this problem, the rotating shaft that connects the turbine and the compressor and the internal combustion engine crankshaft are connected via a clutch and a gearbox, and the internal combustion engine assists the rotation of the compressor during acceleration, thereby responding during acceleration. A supercharger with improved performance has been proposed. (Actual Kaihei 2-1260
(See Publication 36)

[0004]

However, in the supercharger according to the above proposal, the speed increasing ratio of the speed increaser is set so that supercharging can be performed even when the rotation speed of the internal combustion engine is low. Therefore, when the engine speed is high, the turbine and compressor are over-rotated and the clutch is used to disconnect the engine and the compressor to prevent damage to the engine due to excessive supercharging. There is.

On the other hand, in a conventional turbocharger that has not been equipped with a gearbox, it is necessary to bypass the turbine and discharge it to the atmosphere because the exhaust gas becomes excessive when the rotation speed of the internal combustion engine is high. Become. That is, the exhaust gas is exhausted to the atmosphere without recovering the energy, resulting in a result contrary to the request for energy saving. The present invention has been made in view of the above problems, and provides an internal combustion engine with a supercharger that can achieve energy saving by recovering the energy of exhaust gas when the engine speed is high. The purpose is to

[0006]

An internal combustion engine with a supercharger according to a first aspect of the present invention is a compressor for supercharging intake air, which is connected to a turbine driven by exhaust gas discharged from the internal combustion engine and the same rotary shaft as the turbine. And a transmission means for transmitting the rotation shaft torque of the supercharger to the crankshaft of the internal combustion engine, and the transmission of the rotation shaft torque of the supercharger to the crankshaft of the internal combustion engine by the transmission means. A shutoff means for shutting off according to the operating state of the internal combustion engine.

An internal combustion engine with a supercharger according to a second aspect of the present invention is a continuously variable transmission in which a transmission means connects a rotary shaft of the supercharger and a crankshaft of the internal combustion engine. An internal combustion engine with a supercharger according to a third aspect of the present invention provides a continuously variable transmission when the internal combustion engine is operated at a supercharging pressure lower than a target supercharging pressure determined based on the rotation speed and the load of the internal combustion engine. A gear ratio setting means for setting the gear ratio to a gear ratio at which the crankshaft torque of the internal combustion engine is transmitted to the supercharger is further provided.

[0008]

1 is a block diagram of an embodiment of an internal combustion engine with a supercharger according to the present invention. In the internal combustion engine 11, intake air drawn from an air cleaner 121 is taken into an intake pipe 12.
2, supplied through the intake manifold 123. The amount of intake air supplied to the internal combustion engine 11 is controlled by a throttle valve 124 installed midway in the intake pipe.

Exhaust gas discharged from the internal combustion engine 11 is discharged into the atmosphere through an exhaust manifold 131 and an exhaust pipe 132. A turbine 141 driven by exhaust gas is installed midway in the exhaust pipe 132.
22 Compressor 142 installed midway for supercharging intake air
And a rotary shaft 143.

A small-diameter gear 144 is also installed on the rotary shaft 143. The small-diameter gear 144 is fitted with a large-diameter gear 145 to form a speed increasing device. Further, a primary pulley 146 is installed on the crankshaft 111 of the internal combustion engine 11,
A secondary pulley 147 is installed coaxially with the large diameter gear 145. The primary pulley 146 and the secondary pulley 147 are connected by the belt 148. And the primary pulley 1 acting on the belt 148
The speed increasing ratio can be controlled by changing the effective pulley diameters of 46 and the secondary pulley 147.

The primary pulley 146, the secondary pulley 147, and the belt 148 constitute a continuously variable transmission, and a gear ratio S is output in response to an output command from the controller 15.
R, that is, the primary pulley 146 and the secondary pulley 1
The effective pulley diameter of 47 is controlled. That is, the control unit 15 (not shown.) Rotational speed sensor (not shown.) Speed N _e and the throttle sensor for an internal combustion engine 11 detected opening T of the throttle valve 124 detected by
H and H are taken in, and the gear ratio SR is determined accordingly.

FIG. 2 is a flowchart of the first gear ratio control routine. In step 21, the internal combustion engine speed N _e , the throttle valve opening TH and the actual supercharging pressure P _M.
Read. In step 22, the target supercharging pressure P _T is determined as a function of the internal combustion engine speed N _e and the throttle valve opening TH.

P_T= P_T(N_e, TH) FIG. 3 shows the target supercharging pressure P._TIs a graph for determining
The vertical axis is the target boost pressure P _TOn the horizontal axis is the internal combustion engine speed N
_eTake The parameter is the throttle valve opening TH.
You. Actual boost pressure P in step 23_MTarget supercharging
Pressure P_TDetermine if it is higher.

When an affirmative decision is made in step 23, the routine proceeds to step 24, where the gear ratio SR is reduced by 10% and the routine proceeds to step 27. When a negative determination is made in step 23, the routine proceeds to step 25, where it is determined whether the actual supercharging pressure P _M is lower than the target supercharging pressure P _T. When the affirmative judgment is made in Step 25, the routine proceeds to Step 26, the gear ratio SR is increased by 10% and the routine proceeds to Step 27. When a negative determination is made in step 25, the process directly proceeds to step 27.

In step 27, the gear ratio SR is limited to within a predetermined upper and lower limit value. For example, the upper limit rotation speed of the turbine 141 is determined as the rotation speed that leads to mechanical breakdown. On the other hand, the lower limit speed increasing ratio is determined in consideration of the responsiveness when the speed increasing ratio changes from decreasing to increasing. In step 28, the gear ratio SR is output, the gear ratio of the continuously variable transmission is controlled, and this routine ends.

When the internal combustion engine speed after the shift is higher than the turbine speed when the internal combustion engine is driven only by the exhaust gas, the turbine is driven by the internal combustion engine, and conversely, the internal combustion engine speed after the shift is exhausted. The turbine output is recovered by the internal combustion engine when it is below the turbine speed when driven solely by gas. That is, step 23,
In Nos. 24 and 27, the rotational shaft torque of the supercharger is transmitted to the crankshaft of the internal combustion engine by decreasing the speed increasing ratio in the region where the supercharging pressure becomes excessive and the energy of the exhaust gas can be recovered. .

On the other hand, steps 23, 25, 26 and 27
In the region where the supercharging pressure is equal to or lower than the target supercharging pressure, the crankshaft torque of the internal combustion engine is transmitted to the rotary shaft of the supercharger or the torque transmission is interrupted by increasing or changing the speed increasing ratio. To be done. The continuously variable transmission is the turbine 14
No. 1 is fixed to the transmission ratio where power is transmitted to the internal combustion engine 11, and an electromagnetic clutch is installed in the secondary pulley 147, so that the turbine rotation speed becomes low and the power is transmitted from the internal combustion engine 11 to the turbine 141. In this case, it is possible to cut off the transmission of power from the internal combustion engine 11 to the turbine 141.

FIG. 4 is a flow chart of the second gear ratio control routine. In step 41, the internal combustion engine speed N _e and the throttle valve opening TH are read. Step 4
In step 2, the basic gear ratio BSR is determined as a function of the internal combustion engine speed N _e and the throttle valve opening TH. BSR = BSR (N _e , TH) FIG. 5 is a graph for determining the basic gear ratio BSR, where the horizontal axis represents the internal combustion engine speed N _e and the vertical axis represents the throttle valve opening TH. The parameter is the basic gear ratio BSR.

In step 43, the throttle valve opening T
The rate of change ΔTH of H is calculated, and ΔT is calculated in step 44.
It is determined whether H is equal to or larger than a predetermined threshold value α, that is, during acceleration. When an affirmative decision is made in step 44, the routine proceeds to step 45, where the gear ratio correction coefficient KSR is determined as a function of the throttle valve opening change rate ΔTH and the routine proceeds to step 47.

KSR = KSR (ΔTH) When the throttle valve opening change rate ΔTH is large, that is, when it is desired to accelerate more rapidly, the gear ratio correction coefficient KSR is set to a large value. When a negative determination is made in step 44, the routine proceeds to step 46, where the gear ratio correction coefficient KSR is set to 10
% And proceed to step 47.

KSR = 0.9 × KSR In step 47, the gear ratio correction coefficient KSR is multiplied by the basic gear ratio BSR to calculate the gear ratio SR.
Then, the gear ratio SR is output and this routine is finished. That is, according to the second gear ratio control routine, when a rapid acceleration is required, the gear ratio SR is set to be large and the compressor can be driven by the internal combustion engine to improve the feeling of acceleration.

FIG. 6 is a flow chart of the third gear ratio control routine. In step 61, the internal combustion engine speed N _e and the throttle valve opening TH are read. Step 6
In step 2, the basic gear ratio BSR is determined as a function of the internal combustion engine speed N _e and the throttle valve opening TH. BSR = BSR (N _e , TH) The processing up to this point is the second gear ratio control routine.

In step 63, it is determined whether or not it is immediately after the downshift, and if an affirmative determination is made, the process proceeds to step 64. In step 64, it is determined whether the throttle valve opening TH is greater than or equal to a predetermined threshold value β. When an affirmative decision is made in step 64, the routine proceeds to step 65, where the throttle correction coefficient KTH is determined as a function of the throttle valve opening TH, and the routine proceeds to step 66.

KTH = KTH (TH) FIG. 7 is a graph for determining the throttle correction coefficient KTH, in which the horizontal axis represents the throttle valve opening TH and the vertical axis represents the throttle correction coefficient KTH. That is, the smaller the throttle valve opening TH, the larger the throttle correction coefficient KTH, so that the turbine is driven by the internal combustion engine.

When a negative determination is made in step 63 or step 64, the process proceeds directly to step 66. In step 66, the shift ratio, the on / off state of the overdrive switch, or the gear ratio correction coefficient KSR depending on the gear used is calculated. That is, when the low speed gear is used, when the power mode is used as the shift pattern, or when the overdrive switch is turned off, the gear ratio correction coefficient KSR is made large and the turbine is driven by the internal combustion engine.

On the contrary, when a high speed gear is used, when a normal mode is used as a shift pattern, or when the overdrive switch is turned on, the gear ratio correction coefficient KSR is set small to correct the internal combustion engine by the turbine. FIG. 8 is a graph for determining the gear ratio correction coefficient KSR,
The horizontal axis represents the internal combustion engine speed N _e , and the vertical axis represents the gear ratio correction coefficient K.
Take SR.

In step 67, the basic gear ratio BSR
The throttle correction coefficient KTH and the gear ratio correction coefficient KS
The gear ratio SR is calculated by multiplying R. In step 68, the gear ratio SR is limited to within a predetermined upper and lower limit value, and in step 69, the gear ratio SR is output and this routine is ended. That is, according to the present invention, torque transmission from the crankshaft to the turbocharger rotating shaft or from the turbocharger rotating shaft to the crankshaft according to the supercharging pressure is achieved by controlling the gear ratio of the continuously variable transmission. .

[0028]

According to the internal combustion engine with the supercharger according to the first and second claims, when the supercharging pressure is excessive, the axial torque of the supercharger is transmitted to the internal combustion engine, so that the exhaust gas is exhausted. It is possible to recover the energy possessed by the internal combustion engine.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment.

FIG. 2 is a flowchart of a first gear ratio control routine.

FIG. 3 is a graph for determining a target supercharging pressure.

FIG. 4 is a flowchart of a second gear ratio control routine.

FIG. 5 is a graph for determining a basic gear ratio.

FIG. 6 is a flowchart of a third gear ratio control routine.

FIG. 7 is a graph for determining a throttle correction coefficient.

FIG. 8 is a graph for determining a gear ratio correction coefficient.

[Explanation of symbols]

 11 ... Internal combustion engine 121 ... Air cleaner 122 ... Intake pipe 123 ... Intake manifold 124 ... Throttle valve 131 ... Exhaust manifold 132 ... Exhaust pipe 141 ... Turbine 142 ... Compressor 143 ... Rotating shaft 144 ... Small diameter gear 145 ... Large diameter gear 146 ... Primary pulley 147 ... Secondary pulley 148 ... Belt 15 ... Control unit

Claims (3)

[Claims] 1. A supercharger including a turbine driven by exhaust gas discharged from an internal combustion engine, and a compressor connected to the turbine with the same rotary shaft to supercharge intake air, and the supercharger. Means for transmitting the rotation shaft torque of the rotary shaft torque of the turbocharger to the crankshaft of the internal combustion engine, and a cutoff for cutting off the transmission of the rotation shaft torque of the supercharger by the transmission means to the crankshaft of the internal combustion engine according to the operating state of the internal combustion engine. An internal combustion engine with a supercharger comprising: 2. The internal combustion engine with a supercharger according to claim 1, wherein the transmission means is a continuously variable transmission that connects a rotary shaft of the supercharger and a crankshaft of the internal combustion engine. 3. When the internal combustion engine is operated at a supercharging pressure lower than a target supercharging pressure determined on the basis of the rotational speed and the load of the internal combustion engine, the gear ratio of the continuously variable transmission is set to that of the internal combustion engine. The supercharger-equipped internal combustion engine according to claim 2, further comprising a gear ratio setting unit that sets a gear ratio in which crankshaft torque is transmitted to the supercharger.