JPS60206936A - Turbo-supercharged engine - Google Patents

Abstract

PURPOSE:To prevent the deterioration of acceleration by delaying the opening timing of a waist gate valve upon occurrence of delay of the rising of output pressure from a turbo-charger against the engine rotation in case of acceleration for example. CONSTITUTION:Under engine operation, a microcomputer 13 will decide whether the engine load and the rotation to be detected through a load sensor 15 and a rotation sensor 14 are higher respectively than predetermined levels K1, K2. If the answer is YES, the engine rotation increase rate is obtained and decided whether it is higher than predetermined level K3, while upon decision of NO, a signal for opening a waist gate valve 11 is produced immediately. Upon decision of YES, the delay time is counted then an open valve signal is produced to open the waist gate valve 11 through an actuator 12.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a turbocharged engine, and in particular, to supercharging intake air using a turbocharger, and when the engine speed exceeds a predetermined speed. The present invention relates to a turbocharged engine in which a wastegate valve is opened to prevent at least a portion of exhaust gas from escaping through a bypass pipe without passing through the turbine of the turbocharger.

By providing a conventional engine with a turbocharger, it becomes possible to effectively utilize the energy of exhaust gas to compress intake air and supply this intake air to the engine in that state. Therefore, by supplying more intake air, it is possible to improve the output of the engine.

Particularly when the engine speed is high, the pressure of the exhaust gas is also high, and the turbocharger performs the supercharging operation more reliably. However, if the engine rotational speed exceeds the specified rotational speed and becomes excessively high, the intake pressure will also become higher than necessary, which may cause damage to the engine. Therefore, in conventional turbocharged engines, a valve is installed in the waste gate 1, and when the rotation speed exceeds a predetermined number, this valve is opened and a part of the exhaust gas is diverted to the bypass pipe. I'm trying not to escape through the road.

And the operation of such a waste gate valve can be improved even further.
+1f In order to actually do it, for example, JP-A-57-5662
No. 5 proposes a turbocharged engine in which the opening of the waste gate valve is controlled by a microcomputer. In this engine, the rotation speed is detected by a sensor, and
When this rotational speed exceeds a predetermined rotational speed, the wastegate valve is activated and a portion of the exhaust gas is released through the bypass pipe, thereby preventing an abnormal increase in boost pressure. By using the microcontroller in this way, it becomes possible to control the turbocharger more accurately.

On the contrary, if a microcomputer is used to control the opening and closing of the wastegate valve as described in 2 above, a drawback arises in that, for example, sufficient boost pressure cannot be obtained when the vehicle accelerates.

This means that when the accelerator pedal is depressed, the engine speed will respond immediately, but the exhaust gas pressure will respond with a delay.

Therefore, there is a considerable delay in the output pressure of the turbocharger driven by this antagonistic gas reaching a predetermined value.However, when the engine speed reaches a predetermined speed, the wastegate When the valve starts to open, as shown by the chain line in Figure 1, the wastegate valve will hear even though the boost pressure is not sufficient, which will further reduce the boost pressure. The engine had a problem with its acceleration performance deteriorating.

Purpose of the Invention The present invention has been made in view of the above-mentioned problems, especially when the rise of the output pressure of the turbocharger 11-jar is delayed with respect to the rotational speed of the engine at IJtl speed. The object of the present invention is to provide a turbocharged engine that can obtain sufficient boost pressure by delaying the timing at which the wastegate valve is activated.

Structure of the Invention The present invention uses a turbocharger 17 to supercharge intake air, and when the engine rotational speed exceeds a predetermined number of rotations, a wastegate valve is activated to turn on the turbine of the turbocharger. means for determining whether or not the rate of increase in engine speed exceeds a predetermined value in a turbocharged engine which allows at least a portion of exhaust gas to escape through a bypass pipe without passing through the waste gas; and a means for delaying the timing of listening to the waste gate valve, and when the rate of increase in engine speed exceeds a predetermined value, the turbo is configured to delay listening to the waste gate valve. This invention relates to a supercharged engine, and the above object is achieved by this structure.

Example The present invention will be explained below with reference to an illustrated embodiment.

FIG. 2 shows the turbocharged engine 1 according to this embodiment, which is composed of an engine 1G and two easel engines with 0 cylinders. An intake manifold 3 for supplying intake air to each cylinder 2 of this diesel engine 1 is connected to an intake pipe 6 via a compressor tree 5 of a turbocharger 4. The intake pipe 6 is
Intake air is introduced through an air cleaner (not shown). On the other hand, the exhaust gas generated by the combustion explosion in each cylinder 2 of the engine 1 is discharged through the exhaust manifold 7, and this exhaust manifold 7 is connected to the 4
is connected to the turbine 8. And this turbine 8
is connected to the exhaust pipe 9.

A bypass pipe 10 is provided between the 4/1 air manifold 7 and the 1/1 air chamber 9 of the engine 1 for discharging exhaust gas without passing through the turbine 8 of the turbocharger 4. A wastegate valve 11 is disposed on the inlet side of the bypass pipe 10, and the opening of the wastegate valve 11 is controlled by an actuator 12. Further, this actuator 12 is operated based on instructions from a microcombi section 13. The input end of the microcomputer 13 is connected to a rotation detection sensor 14 and a sensor 15 . The rotation detecting wheel 1/1 detects the rotation speed of the fertilizer engine 1 and manually inputs it to the microcomputer 13. In contrast, the load sensor 15 detects the load on the engine 1.

Two-handed J: In the J3 configuration, the exhaust gas produced by the combustion explosion that falls into each syringe 2 of the engine 1 passes through the exhaust manifold 7 to the turbocharger t? The fuel is supplied to the turbine 8 of No. 4, drives this turbine 8, and is discharged from the exhaust pipe 9.

Is the compressor 5 directly connected to the C turbine 8 an intake air? The intake air introduced through 1G is compressed, and this intake air is sequentially supplied to each cylinder 2 of the engine 1 through the intake manifold 3. Therefore, this results in supercharging of the intake air.

During this supercharging, in order to prevent the boost L1 of engine 1 from becoming too high, when the rotation speed of engine 1 reaches a predetermined rotation speed, waste gas 1 to valve 11 are heard. ing. This operation will be explained based on the flowchart shown in FIG. 3. The microphone 1-1 computer 133 reads the load of the engine 1 through the load sensor 15. Furthermore, the microcomputer 13 reads the rotation speed of the engine 1 through the rotation detection sensor 14. Then, it is determined whether the load of engine 1 is greater than a predetermined value 1 in line 4? If the load on the engine is greater than 1, it is determined whether the rotational speed of the engine 1 is greater than 2 at a predetermined rotational speed. Note that if the load or rotational speed of the engine 1 is smaller than 1 or 2, respectively, the process returns to the first step.

Also, if the load of engine 1 and the number of revolutions of engine 1 are both greater than 1 and 2, respectively, then measure the rate of increase in the number of revolutions of engine 1 and judge whether this rate of increase is greater than 3. Rir. If the rate of increase in the rotational speed of the engine 1 is less than 3 J, the normal opening/closing operation of the waste gate valve 11 is performed, that is, a valve opening signal is immediately generated to listen to the waste gate valves 1 to 11. .

Therefore, in the case of ``-
When the number of revolutions of the engine 1 exceeds 2, the waste gate valve 11 is opened immediately. On the other hand, if it is determined that the rate of increase in the rotational speed of the engine 1 is greater than 1 < 3, the delay time is calculated by 4 times, and after counting this time, a valve opening signal is generated, and this signal is West goo 1-valve 1 via actuator 12 based on
1 will be opened.

According to the turbocharged engine 1 according to this embodiment, the rate of increase in the rotational speed of the engine 1 is within a predetermined range (white 1<3
A microcomputer makes a judgment as to whether or not the increase rate has exceeded a predetermined increase rate, and if the rate of increase is below a predetermined rate, the wastegate valve 11 is immediately heard as in the conventional case. Therefore, in this case, part of the exhaust gas is transferred to the bypass pipe 1.
0 to the exhaust pipe 9, the rotational speed of the turbine 8 of the turbocharger 4 is lowered, and an abnormal increase in boost pressure is prevented. On the other hand, for example when accelerating, the engine speed is higher! /V ratio exceeds a predetermined value, even if the engine speed reaches the predetermined speed of 2, the microcomputer 13 cannot issue the valve opening signal until the delay time of 4 has elapsed. Therefore, if the raising operation is being performed, the opening of the waste gate valve 11 will also be delayed. Therefore, as shown by chain 83 i) in FIG. 4, it is possible to prevent the boost pressure from decreasing during acceleration and thereby deteriorating acceleration performance.

Effects of the Invention As described above, the present invention includes means for determining whether the rate of increase in engine speed exceeds a predetermined value, and means for delaying the timing of listening to the wastegate valve. This invention relates to a turbocharged engine in which hearing of the waste gate valves is delayed when the rate of increase in engine speed exceeds a predetermined value. Therefore, according to the present invention, by delaying the timing of listening to the wastegate valve when the rate of increase in engine speed exceeds a predetermined value such as during acceleration,
It becomes possible to prevent deterioration of acceleration performance, and it becomes possible to provide a turbocharged engine with excellent acceleration performance.

[Brief explanation of the drawing]

Fig. 1 shows the change in I-stroke pressure with respect to the rotational speed of a conventional turbocharged engine, and Fig. 2 shows a turbocharged engine according to an embodiment of the present invention. figure,
Figure 3 is a flowchart showing the operation of the microphone 1 button for IFR control of the boost gate valve of this turbocharged engine, and Figure 1 is a flowchart showing the operation of the boost 1-[ It is a graph showing changes in. <r J> In the symbols used in the drawings, 1...Diesel engine 3...Intake manifold 4...Turbocharger 5...Compressor 7...Exhaust manifold 8...Turbine, 9... Exhaust pipe 10...bypass pipe line 11...waste gate valve 12...actuator 13...microcomputer coater 14...rotation detection sensor. Applicant: Hino Motors Co., Ltd.

Claims (1)

[Claims] In addition to supercharging intake air using a turbocharger, when the engine speed exceeds a predetermined speed, a wastegate valve is opened to remove at least part of the exhaust gas without passing through the turbine of the turbocharger. In a turbocharged engine in which part of the engine is discharged through a bypass pipe, means for determining whether the rate of increase in engine speed exceeds a predetermined value, and means for delaying the timing of listening to the waste gate valve. A turbocharged engine, characterized in that opening of the waste gate valve is delayed when the rate of increase in engine speed exceeds a predetermined value.