JP2000110607A - Supercharging pressure control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of hunting phenomenon by setting supercharging pressure lower than an original target supercharging pressure for a constant time, after a condition is transferred from a condition in which fuel cut is executed by traction control means to a condition in which fuel cut is not executed. SOLUTION: It is judged by traction judging part 12 to which a wheel speed signal and the like are inputted from a wheel speed sensor 11 arranged on each wheel 109 whether each wheel slipped on a road surface by excessive driving force or not and a torque-down demand signal (e) is outputted according to its judgment. A fuel injection signal (c) is outputted from a controller 9 to an injector 84 in association with this demand signal (e), however, a fuel cut operation is executed in the case where a value of the demand signal (e) is 'demand'. After an operation is recovered from the fuel cut operation, a valve control signal (a) is outputted for a constant time so as to reduce a value of an intake pressure signal (b) by an intake pressure sensor SR, a bypass valve 5 is drivingly controlled, and supercharging pressure is kept in a low level.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a supercharging pressure control method applied to a vehicle having a supercharger-equipped internal combustion engine and performing traction control.

[0002]

2. Description of the Related Art In recent years, at the time of starting acceleration on a snowy road or the like, the output of an engine is controlled by fuel cut or ignition timing retard in order to suppress wheel spin due to excessive driving force and secure directional stability and driving force of a vehicle. Traction control systems have been developed to reduce torque. As such a traction control system, as described in Japanese Patent Application Laid-Open No. 6-81689, various types of traction control systems have been considered, such as a system in which traction control is not performed at a predetermined engine speed. However, basically, as shown in FIG. 4, when the traction (torque down) request signal input to the controller is set to the "request" state, for example, by detecting slippage of each drive wheel when the vehicle starts. When the fuel cut is performed and the state becomes “not required”, the system is configured to return from the fuel cut.

[0003]

However, in such a configuration in which the traction (torque down) request signal is simply returned from the fuel cut when the traction (torque down) request signal changes to the "non-request" state, the throttle is fully opened. In a vehicle equipped with a supercharged engine such as a turbocharger that requires a high ignition voltage at the time of ignition, the plug is lightly smoldered or smoldered by the influence of oil or residual fuel during fuel cut with a large throttle opening. Therefore, breathing and hiccup phenomena may occur during full-open acceleration immediately after returning from the fuel cut.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a fuel cut by a torque reduction request,
That is, when returning from the traction control, the supercharging pressure is kept low by using the supercharging pressure control means, and then the original target supercharging pressure (full boost) is applied at a timing when the plug condition is recovered. In a vehicle equipped with a supercharger-equipped internal combustion engine, in the past, it could occur immediately after returning from traction control,
Its main purpose is to prevent breathing and hiccups.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A supercharging pressure control method according to the present invention relates to a supercharger and an internal combustion engine having a supercharging pressure control means capable of controlling a supercharging pressure by the supercharger. Traction control means capable of reducing the output torque by performing a fuel cut on the internal combustion engine under predetermined conditions such as a state in which the driving wheels slip on the road surface due to a large driving force. Yes, after shifting from the state in which the fuel cut is performed by the traction control means to a state in which the fuel cut is not performed, for a certain period of time, the supercharging pressure is controlled by the supercharging pressure control means so that the supercharging pressure becomes lower than the original target supercharging pressure. It is characterized in that it is set low.

With such a configuration, by setting the predetermined time to a time required for the plug condition to recover, in the vehicle equipped with the supercharged internal combustion engine, immediately after returning from the traction control, that is, the fuel It is possible to prevent breathing and hiccup phenomena due to poor ignition, which can occur immediately after shifting from the state in which the fuel is cut to the state in which the fuel cut is not performed. Further, by keeping the boost pressure low for a certain period of time, it is possible to obtain an effect of alleviating a shock in which the torque suddenly increases after returning from the traction control.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 mainly shows an engine 1 of a vehicle according to the present embodiment. The vehicle according to the present embodiment is driven by the engine 1, which is an internal combustion engine, and includes at least traction control means for performing traction control.

The engine 1 has a plurality of cylinders 7 (only one is shown in FIG. 1), an intake system 4, an exhaust system 6, and a drive arranged on the exhaust system 6. 1. A turbocharger which is a supercharger having a turbine 22 and a compressor 21 disposed on an intake system 4, and at least a supercharging pressure control means capable of controlling a supercharging pressure by the turbocharger 2. It is.

[0009] The intake system path 4 is used to supply outside air to the intake valve 71 of the cylinder 7.
In this embodiment, on this intake system path 4,
An air cleaner 81, a compressor 21, an intercooler 82, a throttle valve 83, a fuel injector 84, and the like are provided. The exhaust system path 6 communicates the exhaust valve 72 with the outside in order to discharge the exhaust gas discharged from the exhaust valve 72 to the outside. The drive system 22 and an exhaust muffler (not shown) are provided on the exhaust system path 6. Are arranged.

[0010] As described above, the turbocharger 2
The drive turbine 22 and the compressor 21 are provided.
Are arranged coaxially and are configured to work together. Then, the drive turbine 22 is rotated by the exhaust pressure, and the compressor 21 is operated by using the rotational force to perform a pumping operation.
Then, it is sent to the cylinder 7.

Basically, the supercharging pressure control means controls the throttle valve 8 based on the intake inertia and the rotational inertia of the compressor 21 when the throttle valve 83 is rapidly closed.
3 is provided for the purpose of, for example, preventing the pressure on the upstream side of the compressor 3 from temporarily suddenly increasing. For example, the bypass passage 3 connects the downstream side and the upstream side of the compressor 21.
A bypass valve 5 provided on the bypass passage 3 to close and close the bypass passage 3 so as to be capable of opening and closing; and a controller 9 for controlling the bypass valve 5 via a valve control valve VSV. The boost pressure can be freely controlled by opening and closing the bypass passage 3 with the bypass valve 5. In this embodiment, an air-driven bypass valve 5 that opens and closes by moving a valve element 51 provided inside by air pressure is used to indirectly drive the opening and closing of the bypass passage 3 via a valve control valve VSV. However, the configuration of the supercharging pressure control means is not limited to the above-described one. For example, an electromagnetic bypass valve that is directly opened and closed is used.

The traction control means can reduce the output torque of the engine 1 by fuel cut. For example, the traction control means includes a wheel speed sensor 11 provided on each wheel 10.
From the wheel speed signals d and the like output from the wheel speed sensors 11, it is determined whether or not the wheels 10 are slipping on the road surface due to excessive driving force.
The traction determining unit 12 changes the value of the torque-down request signal e, which is a value signal, and outputs the same. The controller 9 receives the torque-down request signal e and outputs a fuel injection signal c to the injector 84. In principle, when the value of the torque-down request signal e is “request” (on), traction control, that is, fuel cut is performed, and when the value is “non-request” (off), Inject fuel as usual. The traction determination unit 12 and the controller 9 may be an integrated device.

The controller 9 partially having the functions of the supercharging pressure control means and the traction control means includes at least an input interface 91, an output interface 92,
It incorporates a PU 93 and a memory 94. The input interface 91 receives at least the intake pressure signal b output from the intake pressure sensor SR and the torque-down request signal e. The output interface 92 drives the valve control valve VSV. At least a valve control signal a for controlling and a fuel injection signal c for driving and controlling the injector 84 are output. In the present embodiment, at least a supercharging pressure control program for performing supercharging pressure control is stored in the memory 94, and is repeatedly executed. This supercharging pressure control program will be described below with reference to the flowchart shown in FIG.

First, in step 1, whether the value of the torque down request signal e is "request" (on) or "not required"
(OFF). Torque down request signal e
Is "request" (ON), the process proceeds to step S2, and if not, the process proceeds to step S4. Step S2
Then, it is determined whether or not a fuel cut is being performed. If the fuel is being cut, the process returns to step S1, and if not, the process proceeds to step S3.

In step S3, the injector 84 is driven by the fuel injection signal c to perform fuel cut. Then, the process returns to step S1. On the other hand, in step S4, it is determined whether or not the fuel is being cut. If the fuel is being cut, the process proceeds to step S5, and if not, the process returns to step S1. In step S5, a return process from the fuel cut, such as stopping the fuel cut, is performed. Then, the process proceeds to step S6.

In step S6, the boost pressure is kept low for a certain time after returning from the fuel cut. Specifically, the valve control signal a is output so that the value of the intake pressure signal b output from the intake pressure sensor SR becomes smaller than the value when this step is not performed.
V, drive control of the bypass valve 5. Then, the process returns to step S1. Here, the certain time is a time from when the fuel cut is restored to when the plug condition of the ignition plug (not shown) recovers, and is calculated in advance by experiments or the like.

Note that in conditions other than step S6, the supercharging pressure is not kept low in this routine in principle. The present embodiment thus configured is as shown in FIG. 3 in a functional block diagram. That is, comparing this with the conventional one (FIG. 4), the difference is that the supercharging pressure control is performed.

Therefore, according to the present embodiment configured as described above, the supercharging pressure is kept low by using the supercharging pressure control means for a fixed time after returning from the fuel cut due to the torque down request (step S6). Then, the original target supercharging pressure (full boost) is applied in anticipation of the timing at which the plug condition recovers. Therefore, in a vehicle equipped with such an engine 1 with a turbocharger, conventionally, the traction control is performed. It is possible to prevent breathing and hiccup phenomena caused by poor ignition that can occur immediately after the return.

Further, by keeping the supercharging pressure low for a certain period of time, it is possible to alleviate a shock in which the torque suddenly increases after returning from the traction control, and to improve the drivability. The present invention is not limited to the above-described embodiment, but is not limited to the illustrated example, and various modifications can be made without departing from the gist of the present invention.

[0020]

As described in detail above, according to the present invention,
In a vehicle equipped with a supercharger-equipped internal combustion engine, after returning from traction control, the supercharging pressure is set to be lower than the original target supercharging pressure for a certain period of time. By setting to, it is possible to prevent breathing and hiccup phenomena that can occur immediately after returning from traction control. Further, by keeping the supercharging pressure low for a certain period of time, it is possible to alleviate a shock in which the torque is sharply increased after returning from the traction control, and to improve the drivability.

[Brief description of the drawings]

FIG. 1 is a schematic overall view mainly showing an engine of a vehicle according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a supercharging pressure control method in the embodiment.

FIG. 3 is a functional block diagram of the embodiment.

FIG. 4 is a functional block diagram of a conventional example.

[Explanation of symbols]

 1: Internal combustion engine (engine) 2: Supercharger (turbocharger)

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3G093 AA01 AB02 BA01 BA02 DA03 DB02 DB23 EA05 EB07 3G301 HA11 JA04 JA38 KA27 LA00 PA07Z

Claims (1)

[Claims] An internal combustion engine comprising a supercharger and a supercharging pressure control means capable of controlling a supercharging pressure by the supercharger, and an internal combustion engine under a predetermined condition such as a state where an excessive driving force is applied. The invention is applied to a vehicle having traction control means capable of reducing the output torque by performing a fuel cut on the engine, and shifting from a state in which the traction control means performs the fuel cut to a state in which fuel can be supplied. After doing
A supercharging pressure control method, wherein the supercharging pressure is set to be lower than an original target supercharging pressure by the supercharging pressure control means for a predetermined time.