JPS597744A - Air intake device for engine with supercharger - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intake system for a partial supercharging engine that performs supercharging from an auxiliary intake passage during high loads.

Conventionally, in order to improve the output of automobile engines under high loads, a main intake system and an auxiliary intake system were installed together, and the auxiliary intake system was equipped with a supercharger. Partially supercharging engines are known in which supercharging air is supplied from an auxiliary intake system in addition to intake air from the main intake system when the load exceeds the load. In this type of engine, if a fuel supply means is provided only in the main intake system, the intake air temperature will rise due to adiabatic compression in the auxiliary intake system, causing problems such as deterioration of volumetric efficiency.

For this reason, as shown in Japanese Patent Application No. 56-213727, fuel injection nozzles are provided in both the main intake system and the auxiliary intake system, and fuel is also injected from the fuel injection nozzle of the auxiliary intake system during supercharging. A structure has been proposed in which the latent heat of vaporization is used to lower the intake air temperature and to eliminate the imbalance in the air-fuel ratio during supercharging. In this structure, the fuel injection nozzle of the auxiliary intake system normally injects fuel once per cycle of the engine at a predetermined timing corresponding to engine operation when the engine is in the supercharging range (above the set load). controlled to spray. However, this alone will cause a delay in the fuel injection timing when switching to the supercharging region due to the acceleration signal, unless that point coincidentally coincides with the above fuel injection timing, and this delay will result in a delay in the fuel injection timing at the beginning of the supercharger operation. As a result, acceleration is not performed smoothly, and there is a risk that problems such as so-called acceleration heditation may occur.

In view of these circumstances, the present invention reliably prevents the air-fuel mixture from becoming over-lean at the initial stage of supercharger operation during acceleration in a partially supercharged engine in which fuel injection nozzles are provided in each of the main and auxiliary intake systems. The present invention aims to provide an intake device that can improve acceleration performance.

That is, the present invention not only injects fuel from the fuel injection nozzle of the auxiliary intake system at a predetermined timing in the supercharging region, but also injects fuel independently of the timing in the initial state of operation of the supercharger. The present invention is characterized by comprising a control device that controls the fuel injection nozzle of the auxiliary intake system so as to do the following.

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is a cylinder of an engine, 2 is a piston, and 6 is a combustion chamber formed in the upper part of cylinder 1. In FIG.

The combustion chamber 6 includes a main intake boat 4 and an auxiliary intake port 1-5.
and exhaust port 6 are opened, and each of these ports 1-4.
5. 6 are each equipped with a main intake valve 7, an auxiliary intake valve 8, and an exhaust valve 9. The main intake valve 7 is opened during most of the intake stroke, and the auxiliary intake valve 8 is opened at the end of the intake stroke or at the beginning of the compression stroke, and closed during the compression stroke.

11 is a main intake passage, and 12 is an auxiliary intake passage, which communicate with the main intake boat 4 and the auxiliary intake boat 5, respectively.

The main intake passage 11 is provided with a throttle valve 16 that is operated in conjunction with an accelerator (not shown). On the other hand, a supercharger 14 such as a vane pump is provided in the auxiliary intake passage 12, and downstream of the supercharger 14, a supercharging valve 15 is provided that opens when the engine load reaches a set value.
is provided. Further, in the illustrated embodiment, a secondary air supply passage 17 that supplies secondary air to the exhaust passage 16 branches from a position between the supercharger 14 and the supercharging valve 15 in the auxiliary intake passage. . A secondary air flow meter control valve 18 is provided at this branch portion, which is controlled appropriately depending on the operating state. In such a case, the supercharger 14 functions as the original intake supercharging when the load exceeds the set load at which the auxiliary intake passage 12 is opened, and also serves as a secondary air supply pump that sends secondary air to the exhaust system when necessary. Also serves as 19 is a relief passage communicating with the secondary air supply passage 17; 20 is the IJ
This is a relief valve installed in the IJ-F passage 19.

A main fuel injection nozzle 21 and an auxiliary fuel injection nozzle 22 are provided in the main intake passage 11 and the auxiliary intake passage 12, respectively. Further, 26 is an air flow meter arranged in the main intake passage 11 to detect the intake flow rate of the main intake system, and 24 is an air flow meter arranged in the auxiliary intake passage 12 to detect the flow rate of supercharging air. , 25 detects the opening degree of the throttle valve 16, that is, the engine load.
26 is a crank angle sensor. Each of these detection signals is transmitted to each type of injection nozzle 21.2.
The signal is inputted to a control circuit 60 that controls the operation of 2.

The control circuit 60 is configured as shown in FIG. That is, in the control circuit 60, the main side control section 61 that controls the main fuel injection nozzle 21 is provided with a main side pulse width determining circuit 62 that receives signals from the crank angle sensor 26 and the intake air flow meter 26. There is. This circuit 62 generates one fuel injection pulse per cycle at a predetermined timing corresponding to the operation of the engine, and has a width corresponding to the intake flow rate of the main intake system. The main fuel injection nozzle 21 is actuated. The auxiliary side control unit 64 that controls the auxiliary fuel injection nozzle 22 also includes a reference level setting circuit so that fuel is injected from the auxiliary fuel injection nozzle 22 at a predetermined timing in a supercharging region where the engine has a set load or more. 55, a comparison circuit 66, and auxiliary pulse width determination circuits 6-67. The comparison circuit 66 compares the reference level corresponding to the set load with the detection signal of the throttle opening sensor 25, and generates an output signal when the supercharging range is equal to or higher than the set load. The auxiliary pulse width determining circuit 67 operates only in the supercharging region based on the output signal from the comparator circuit 66.

Then, in response to signals from the crank angle sensor 26 and the auxiliary intake side air flow meter 24, one air flow meter is sent every cycle at a predetermined timing synchronized with engine operation.
A fuel injection pulse with a width corresponding to the supercharging air flow rate of the auxiliary intake system is generated. Furthermore, the auxiliary side control unit 64 is configured to operate the auxiliary fuel injection nozzle 22 independently of the above-mentioned timing in the actual initial operating state of the supercharger 14, that is, in the state immediately after the supercharging region is over the set load. As a control device, a one-shot multivibrator 68, a gate 69, and an OR circuit 4o are incorporated. The one-shot multivibrator 68 receives the output of the comparator circuit 66 and generates a pulse asynchronous to the operation of the engine when the load is switched to a set value or higher. The gate 69 is
When pulse signals are generated simultaneously in the one-shot multivibrator 68 and the auxiliary pulse width setting circuit 6Z, the asynchronous pulse signal from the one-shot multivibrator 68 is cut off, and at other times, the asynchronous pulse signal is transmitted. Then, either this asynchronous pulse signal or the pulse signal from the supplementary pulse width undetermined circuit 67 is output from the OR circuit 4°, and the supplementary first rule is set so that the supplementary fuel injection nozzle 22 is operated via the drive circuit 41. A control section 64 is configured.

The operation of this device will be explained next.

Air is taken into the combustion chamber 6 of the engine only from the main intake passage 11 when the load is below the set load. When the load exceeds the set load,
The supercharging valve 15 is opened, and the secondary air flow rate control valve 18 is also kept open to the auxiliary intake passage 12, so that in addition to the intake air from the main intake passage 11, the auxiliary intake passage 12 is Charge air is sent 9 into the combustion chamber 6.

In response to this intake operation, each of the main and auxiliary fuel injection nozzles 21, 22 is actuated by a pulse signal generated in the control circuit 60 as shown in FIG. That is, FIG. 6(A) shows the fuel injection pulse signal P1 obtained in the main control section 61 of the control circuit 60. This pulse signal P1 is generated in the entire operating range of the engine with the timing and pulse width determined by the main side pulse width determining circuit 62, and fuel is injected from the main fuel injection nozzle 21 for only the generation time of this pulse signal P1. . FIG. 6(B) shows a pulse signal obtained in the auxiliary control section 64 of the control circuit 6o. In the figure, tT represents the time period in the operating range below the set load, tH represents the time period in the supercharging range above the set load, and 'to represents the time point of switching to the supercharging range during acceleration. Further, P2... is a synchronous pulse signal corresponding to engine operation generated with a predetermined timing and pulse width determined by the auxiliary pulse width determining circuit 67, and P3 is a one-shot multivibrator 68.
The fuel is injected from the auxiliary fuel injection nozzle 22 only during the generation time of these pulse signals.

9- The above synchronized pulse signal P2... is generated only in the supercharging region,
In addition, if the generation timing and the above-mentioned switching time to are different from each other, the first synchronization pulse signal P is generated from the switching time to.
Until the time point 2 occurs, a delay time as close as possible to one cycle of the engine occurs. For this reason, in the conventional structure that generates only synchronous pulses, the auxiliary intake passage 1
From 2 onwards, only air is supplied in excess, resulting in an over-lean condition. In such a case, since the asynchronous pulse P3 is generated at the switching time to, fuel is reliably injected from the auxiliary fuel injection nozzle 22 at the initial stage of supercharging, and over-lean is prevented.

Note that if the switching time to and the timing of generation of the synchronous pulse signal P2 coincidentally, the asynchronous pulse P2
Since it is not necessary to send 3, it is blocked by the gate 69 and the fuel injection nozzle 22 is operated by the synchronous pulse P2.

As described above, the device of the present invention provides an engine in which a fuel injection nozzle is also provided in the auxiliary intake passage for supercharging, and fuel is injected from the fuel injection nozzle at a predetermined timing in the supercharging region. In this system, a control device is provided that injects fuel from the fuel injection nozzle independently of the timing at the initial stage of supercharging, so that the air-fuel mixture becomes over-lean immediately after reaching the supercharging range of the set load tool during acceleration. It is possible to reliably prevent this from happening, improve responsiveness to acceleration operations, and prevent acceleration displacement.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing an embodiment of the device of the present invention, Fig. 2 is a block diagram of a control circuit in the same device, and Figs. 6 (A) and 6 (B) show pulse signals obtained in the control circuit. It is an explanatory diagram. 1... Engine cylinder, 11... Main intake passage, 1
2... Auxiliary intake passage, 14... Supercharger, 21.22
...Fuel injection nozzle, 60...Control circuit, 65...
・Reference level setting circuit, 66... Comparison circuit, 67...
- Auxiliary side pulse width determination circuit, 38... one-shot multivibrator. Patent applicant: Toyo Kogyo Co., Ltd. Representative: Patent attorney: Etsuka Kotani

Claims (1)

[Claims] 1. The intake system of the engine is composed of a main intake system and an auxiliary intake system, and the auxiliary intake system is equipped with a supercharger that supplies supercharging air at a load higher than the set load of the engine, and each of the main and auxiliary intake systems is In a supercharged engine configured to include a fuel injection nozzle and inject fuel at a predetermined timing from the fuel injection nozzle interposed in the auxiliary intake system in the supercharging region, the initial operating state of the supercharger An intake system for a supercharged engine, comprising: a control device for controlling a fuel injection nozzle of the auxiliary intake system so as to inject fuel independently of the timing.