JPH0121143Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention is used as a boost pressure control device for a vehicle engine equipped with a turbocharger.

(Prior Art and its Problems) As shown in FIG. 2, the torque characteristics of a turbocharged vehicle engine at full load generally tend to increase rapidly near the point where the turbocharger begins to work effectively. When the vehicle's shift position is at a low speed shift position such as 1st gear,
Since the rate of increase in the engine speed is large and the torque increases rapidly, there is a problem in that the tires slip and spin, which impairs steering stability.

Incidentally, Japanese Patent Application Laid-open No. 168222/1983 discloses a prior art technique in which boost pressure is increased for a predetermined period of time during engine acceleration to improve vehicle acceleration.
According to this prior art, there is a problem in that tire spin is more likely to occur.

(Purpose of the invention) The purpose of the invention is to solve the above problems.

(Structure of the invention) In order to achieve the above object, the present invention detects engine rotation speed in a boost pressure control device for a vehicle engine that controls boost pressure by opening and closing a waste gate or an intake relief gate of a turbocharger. and a gate opening/closing means for adjusting the opening/closing of the waste gate or intake relief gate, and a basic map regarding the reference set boost pressure corresponding to the engine speed and a correction corresponding to the engine speed increase rate. A correction map indicating coefficients is stored in the storage unit, and a target is determined from the basic map and the correction map based on the engine rotation speed input from the engine rotation speed detection means and the engine rotation increase rate obtained by time-processing the engine rotation speed. The control means calculates a set supercharging pressure and controls the gate opening/closing means so that the supercharging pressure of the intake system matches the target set supercharging pressure, and the correction coefficient of the correction map is determined based on the engine speed increase rate. is characterized in that the target supercharging pressure is lowered from the reference supercharging pressure when is equal to or greater than a predetermined value.

(Example) The present invention will be specifically described below based on an example shown in the drawings.

FIG. 1 shows a device for controlling supercharging pressure by opening and closing a wastegate 2 in a vehicle engine equipped with a turbocharger 1. As shown in FIG. The intake system A of the engine includes a supercharging blower 6 of a turbocharger 1, a surge tank 7, and a carburetor 8.
On the other hand, the exhaust system B of the engine is provided with an exhaust turbine 9 of the turbocharger 1 and an exhaust bypass passage 10 that bypasses the exhaust turbine 9.

The waste gate 2 of the exhaust bypass passage 10 is opened and closed by a waste gate valve 12 driven by a diaphragm actuator 11. Supercharging pressure downstream of the supercharging blower 6 is introduced into the pressure chamber 13 of the actuator 11 through a supercharging pressure introduction passage 14 . When the pressure introduced into the pressure chamber 13 becomes equal to or higher than a predetermined pressure, the waste gate valve 12 is opened to guide a part of the exhaust gas to the exhaust bypass passage 10 through the waste gate 2, and the exhaust gas is guided to the exhaust turbine 9. By suppressing the output of the intake system A, the supercharging pressure of the intake system A is prevented from rising above a predetermined pressure.

A leak valve 5b controlled by a control unit 5a is arranged in the supercharging pressure introduction passage 14. This leak valve 5b includes an atmosphere release pipe 15,
It is composed of electromagnetic valves connected to three points, an upstream pipe 14a of the supercharging pressure introduction passage 14, and a downstream pipe 14b thereof, and the supercharging air introduced through the upstream pipe 14a is passed through the atmosphere opening pipe 15. Constructed in such a way that it can leak into the atmosphere. The amount of air leakage is adjusted by controlling the ON/OFF ratio (duty ratio) of the solenoid valve 5b by the control unit 5a. Therefore, since the pressure reduction ratio f is determined by the amount of leakage, the pressure _P1 in the pressure chamber 13 is expressed in relation to the supercharging pressure P of the intake system A as shown in the following equation.

P ₁ ≒ (1-f) P If the pressure in the pressure chamber 13 required for the waste gate valve 12 to open is P ₁₀ , then the intake system A
The maximum boost pressure, that is, the set boost pressure P ₀ is expressed by the following formula.

P ₀ ≒ P ₁₀ / (1-f) (1) Since P ₁₀ is a constant, it can be set by controlling f by the control means 5 consisting of the control unit 5a and the leak valve 5b. The supercharging pressure P ₀ can be adjusted arbitrarily.

Detection data from an engine rotation speed detecting means 3 for detecting the engine rotation speed is inputted to the control unit 5a. Further, the control unit 5a is configured to be able to time-process the detection data, that is, the engine rotation speed data inputted at predetermined time intervals, and calculate the rate of increase in engine rotation.

The storage section of the control unit 5a stores a basic map regarding reference setting boost pressures corresponding to engine speeds. FIG. 3 is an example of this basic map using a graph. Further, the storage section stores a correction map showing correction coefficients corresponding to the rate of increase in engine speed. Figure 4 shows an example of this correction map using a graph, where the correction coefficient is 1 when the rate of increase in engine speed is less than E ₁ , a value that decreases linearly when E ₁ to _{E 2} ,
When E is ₂ or more, a constant value smaller than 1 (e.g. 0.5)
It can be determined as follows. The basic map and the correction map can be obtained not only by storing data in a table format in the storage unit, but also by storing data indicating calculation formulas in the storage unit.

The set boost pressure to be controlled by the control unit 5a, that is, the target set boost pressure, is obtained by multiplying the reference set boost pressure determined by the engine speed by a correction coefficient determined by the engine speed increase rate. It is required by certain things. Then, when this target set boost pressure is determined, the pressure reduction ratio f
is determined, and a solenoid valve ON/OFF ratio control signal matching this is output from the control unit 5a to the leak valve 5b. It goes without saying that a series of operations such as the calculation and the control signal are performed according to a program given to the control unit 5a. As a result, when the engine speed increase rate is E ₁ or more, the target boost pressure is set to a value that corrects the reference boost pressure setting, that is, a value that is lower than the reference boost pressure setting. The supercharging pressure of the intake system A is controlled so as to match.
In addition, when the engine speed increase rate is smaller than E ₁ ,
The target set boost pressure corresponds to the reference set boost pressure.

In the above embodiment, the above control is performed by determining the target supercharging pressure on the premise that the rate of increase in engine speed tends to increase when the vehicle shift position is at a low speed shift position such as 1st speed. However, if it is desired to perform the above control only at a low speed shift position such as the first speed, the control unit 5a detects the shift position by the shift position detection means 16 as shown by the imaginary line in FIG. It may be configured such that a shift position detection signal is input and the above correction is performed only when the shift position is at a low speed shift position.

Further, as shown by the imaginary line in FIG. 1, the supercharging pressure of the intake system A is detected by the supercharging pressure detection means 17, and this is input to the control unit 5a, and this supercharging pressure and the target setting are detected. It may be configured to perform feedback control by comparing the boost pressure. In this case, the leak valve 5b and its control signal can be simplified.

Furthermore, as shown by the imaginary line in FIG. 1, the presence or absence of rain is detected by the raindrop detection means 18, and this is input to the control unit 5a, and the correction coefficient at the time of rain is shown in FIG. As shown by the imaginary line, it is preferable to configure the tire height to be lower than that in the normal case to prevent tire spin during rain.

The present invention can be configured in various manners other than those described in the above embodiments. For example, the present invention can be applied to a system that controls boost pressure by opening and closing an intake relief gate instead of the waste gate 2 of the turbocharger 1. Further, the gate opening/closing means 4 is not limited to one driven by the diaphragm type actuator 11, and the valve itself can be directly driven by a solenoid. Furthermore, the present invention can also be applied to a vehicle engine equipped with an electronically controlled fuel injection device.

(Effect of the invention) The present invention has the above configuration, and controls the boost pressure of the intake system to a low level in the range where the engine output torque rapidly increases, that is, in the range where the engine speed increase rate becomes larger than a predetermined value. Since the output torque of the engine can be controlled, tire spin can be prevented and steering stability can be improved.

[Brief explanation of the drawing]

Fig. 1 is a system diagram of an embodiment of the present invention, Fig. 2 is a graph showing the relationship between engine speed and torque, Fig. 3 is a graph showing the relationship between engine speed and reference set boost pressure, and Fig. 3 is a graph showing the relationship between engine speed and reference setting boost pressure. FIG. 4 is a graph showing the relationship between the engine speed increase rate and the correction coefficient. 1... Turbo charger, 2... Waste gate, 3... Engine speed detection means, 4... Gate opening/closing means, 5... Control means, A... Intake system.

Claims (1)

[Scope of utility model registration request] In a vehicle engine supercharging pressure control device that controls supercharging pressure by opening and closing a waste gate or an intake relief gate of a turbocharger, an engine rotation speed detection means for detecting engine rotation speed;
A storage unit includes a gate opening/closing means for adjusting the opening/closing of the waste gate or the intake relief gate, and stores a basic map regarding a reference set boost pressure corresponding to the engine speed and a correction map showing a correction coefficient corresponding to the engine speed increase rate. In addition to having
Based on the engine speed input from the engine speed detection means and the rate of increase in engine speed obtained by time-processing the same, a target set boost pressure is calculated from the basic map and the correction map, and the boost pressure in the intake system is calculated. comprising a control means for controlling the gate opening/closing means so that the supply pressure matches the target set supercharging pressure,
A supercharging pressure control device for a vehicle engine, wherein the correction coefficient of the correction map lowers the target supercharging pressure setting from the reference supercharging pressure setting when the engine speed increase rate is equal to or higher than a predetermined value.