JP2004293298A - Device for preventing abnormal racing of engine and method for controlling the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent abnormal racing of an engine even if oil in blow-by gas can not be separated due to abnormality of a blow-by gas separation device. <P>SOLUTION: This device for preventing abnormal racing of the vehicular engine is provided with a compression pressure release type brake B as an engine brake and includes a fuel injection quantity detection means 11, an intake air quantity detection means 12 and, or an intake air pressure detection means, an exhaust gas temperature detection means 13, and engine speed sensor 14, and a control means 10. The control means 10 operates the compression pressure release type brake B to forcedly stop fuel injection if fuel injection quantity is a predetermined value or less, intake air quantity is a predetermined value or more, and , or intake air pressure is a predetermined value or more, exhaust gas temperature is a predetermined value or more, engine speed is a predetermined value or more and the engine is continuously operated for a predetermined period of time or longer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a device for preventing abnormal rise of a vehicle engine provided with a compression pressure release type brake which is an engine brake, and a control method thereof.
[0002]
[Prior art]
If the oil in the blow-by gas cannot be separated due to an abnormality in the blow-by gas separation device, the oil will flow back into the cylinder of the engine and the engine speed will increase abnormally regardless of the driver's intention. The "rise" phenomenon occurs.
[0003]
On the other hand, the present invention relates to a blow-by gas processing device for an engine that separates and treats a blow-by gas and an oil component in an engine, and is capable of preventing abnormal combustion even if the blow-by gas is recirculated to an intake pipe and recombusted. A gas processing device is disclosed (for example, see Patent Document 1).
[0004]
However, even with such a conventional technique, it is difficult to prevent the engine from abnormally rising when an abnormality occurs in the blow-by gas separation device.
[0005]
[Patent Document 1]
JP 2002-295224 A
[Problems to be solved by the invention]
The present invention has been proposed in view of the above-described problems of the related art. Even when the oil in the blow-by gas cannot be separated due to an abnormality of the blow-by gas separation device, it is possible to prevent "abnormal blow-up" of the engine. And a control method therefor.
[0007]
[Means for Solving the Problems]
An abnormal engine lift-up prevention device according to the present invention is an abnormal engine lift-up prevention device for a vehicle engine provided with a compression pressure release type brake (B) which is an engine brake. It has a detecting means (12) and / or an intake pressure detecting means, an exhaust temperature detecting means (13), an engine rotation sensor (14), and a control means (10). The amount is equal to or less than a predetermined value, the intake air flow rate and / or the intake pressure is equal to or more than a predetermined value, the exhaust temperature is equal to or more than a predetermined value, and the engine speed is equal to or more than a predetermined value and the engine has been continuously operated for a predetermined time or more. In this case, the compression pressure release type brake (B) is operated to forcibly stop the fuel injection (claim 1).
[0008]
An abnormal engine uplift prevention control method according to the present invention includes a step (S3) of determining whether or not a fuel injection amount is equal to or less than a predetermined value based on information from a fuel injection amount detection means (11); A step (S5) of determining whether or not the intake air amount is equal to or more than a predetermined amount based on information from the means (12) and / or whether or not the intake pressure is equal to or more than a predetermined value based on information from the intake pressure detecting means Determining whether the exhaust gas temperature is equal to or higher than a predetermined value based on information from the exhaust temperature detecting means (13) (S7), and based on information from the engine rotation sensor (14). Determining whether or not the engine has been operated for a predetermined period of time at a predetermined engine speed or higher (S9), wherein the fuel injection amount is equal to or lower than a predetermined value and the intake air flow rate is lower than a predetermined value. And / or the intake pressure is When the exhaust gas temperature is equal to or higher than a predetermined value, the exhaust gas temperature is equal to or higher than a predetermined value, and the engine speed is equal to or higher than the predetermined value and the engine is continuously operated for a predetermined time or more, the compression pressure release type brake (B) is operated, Is forcibly stopped (claim 2).
[0009]
Here, regarding the configuration of the compression pressure release type brake (B), an auxiliary brake technology proposed by the present applicant, a so-called “EEB (Nissan Diesel Industrial Co., Ltd., trade name: exhaust from the compression stroke to the expansion stroke of the engine). A valve operating mechanism that opens the valve slightly, discharges the compressed air to the outside of the combustion chamber, and effectively pulls out the engine brake by reducing the acceleration force of the piston during the expansion stroke can be used.
[0010]
According to the abnormal blow-up prevention device and the control method of the engine of the present invention having the above-described configuration and control method, even if an abnormality occurs in the low-by gas separation device and the oil in the blow-by gas cannot be separated, such a situation can be quickly solved. The engine can be forcibly stopped before the engine "abnormally blows up" to prevent a serious accident from occurring.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
First, the configuration of a compression-release brake B, which is one type of engine brake, will be described. In FIG. 1, an exhaust port 3 that opens to the cylinder 2 side of the cylinder head 1 is opened by lowering the exhaust valve 4 and is closed by raising the exhaust valve 4.
[0012]
The valve operating mechanism of the exhaust valve 4 includes the exhaust valve 4, a return spring (not shown), a rocker arm 5, a rocker shaft 6, a push rod 7, a cam 8, and an exhaust valve (or arbitrarily) during intake. And a hydraulic actuator 9 which is an intake exhaust valve opening means for opening the valve.
[0013]
The exhaust valve 4 is pushed upward by the reaction force of the return spring (not shown) (the state shown by the solid line in the figure).
When the convex portion of the cam 8 is located above in the figure, the cam 8 pushes up the push rod 7, and the push rod 7 pushes up the illustrated right end 5 a of the rocker arm that rotates around the rocker shaft 6.
The rocker arm 5 pivoted around the rocker shaft 6 and the left end 5b of the rocker arm 5 descends with the right end 5a pushed up (the state shown by the broken line in the figure), so that the exhaust valve 4 abutting on the left end 5b is pushed down, Open the exhaust port 3.
[0014]
On the other hand, between the exhaust side rocker arm 5 and the rocker shaft 6, there is provided an eccentric bush 20 in which the center of the outer periphery is eccentric with respect to the axis of the rocker shaft 6.
A lever 20a is fixed to the eccentric bush 20, and a tip of a connecting rod 9a of the hydraulic actuator 9 is rotatably connected to a tip of the lever 20a.
[0015]
The hydraulic actuator 9 operates by receiving a hydraulic pressure from a hydraulic pump 22 via a hydraulic pipe 24 with a switching valve V interposed therebetween.
The operation of the switching valve V is controlled by receiving a command signal of an engine controller (control means in the claims 1 and 2; hereinafter, the control means is referred to as an engine controller) 10 through a signal line Lo. .
[0016]
That is, in the case of operation, the engine controller 10 transmits a control signal for switching the circuit (state shown) so that the hydraulic pressure acts on the switching valve V on the hydraulic actuator 9 side.
[0017]
When hydraulic pressure acts on the hydraulic actuator 9, the hydraulic actuator 9 pushes out the connecting rod 9a, and the lever 20a connected to the connecting rod 9a and the eccentric bush 20 integrated with the lever 20a rotate around the rocker shaft 6.
[0018]
Therefore, the rocker arm 5 that rotates around the outer periphery of the eccentric bush 20 rotates downward (counterclockwise) to the position shown by the broken line in the drawing with the tip of the ball of the ball stud 5ab fixed to the right end 5a of the rocker arm as a fulcrum. Then, the exhaust valve 4 is pushed down as shown by the broken line. As a result, a gap is formed between the exhaust valve 4 and the exhaust port 3, and a part of the exhaust gas of the exhaust system flows back into the cylinder 2 in the case of the intake process.
[0019]
Then, a part of the exhaust gas circulates into the cylinder 2 during the intake stroke, whereby the engine output sharply decreases, and as a result, the engine brake operates.
Note that, in FIG. 1, reference symbol A indicates an air cleaner, and T indicates a supercharger.
[0020]
On the other hand, sensors of the control system include a rack sensor 11 which is a fuel injection amount detecting means interposed in the injection pump IP, and an air flow meter which is an intake air amount detecting means interposed in the intake system (intake pipe) 30. An exhaust temperature sensor 13 and an engine rotation sensor 14 interposed in an exhaust system 40 are connected to the engine controller 10 by an input signal line Li.
The injection pump IP may be an in-line pump system, a common rail system, or a unit injector system.
[0021]
Next, a control method of the embodiment will be described with reference to FIG. 2 and also to FIG.
[0022]
First, the engine controller 10 performs normal control (step S1), and the fuel injection amount is detected by the rack sensor 11 (step S2).
[0023]
The engine controller 10 constantly checks whether the fuel injection quantity (q) is equal to or less than a predetermined value (a loop from step S3 to step S2). The process proceeds to the next step S4 after (YES in step S3).
[0024]
In step S4, the intake pressure is detected by the air flow meter 12, and the engine controller 10 constantly determines whether the intake pressure has reached a predetermined value or more (a loop of steps S5 to S4). When the atmospheric pressure has reached a predetermined value or more (YES in step S5), the process proceeds to the next step S6.
[0025]
In step S6, the exhaust gas temperature is detected by the exhaust gas temperature sensor 13, and the engine controller 10 constantly determines whether or not the exhaust gas temperature has reached a predetermined value or higher (a loop of steps S7 to S6). If the exhaust gas temperature has reached a predetermined value or higher (YES in step S7), the process proceeds to the next step S8.
[0026]
In step S8, the engine speed is detected by the engine speed sensor 14, and the engine controller 10 constantly determines whether or not the engine speed is equal to or more than a predetermined value and a predetermined time or more has elapsed ( In a loop of steps S9 to S8), when the engine speed is equal to or higher than the predetermined value and the predetermined time has elapsed (YES in step S9), the process proceeds to the next step S10.
[0027]
That is, the engine controller 10 determines that the fuel injection amount (q) is equal to or lower than the predetermined value, the intake air flow rate is equal to or higher than the predetermined value, and / or the intake pressure is equal to or higher than the predetermined value, and the exhaust temperature is equal to or higher than the predetermined value. When the engine speed is equal to or higher than a predetermined value and the engine is continuously operated for a predetermined time or longer, a control signal is sent to a switching valve V via a signal line Lo to operate the compression pressure release type brake B, and compression is performed. During the process, the exhaust valve is slightly opened, and a control signal is transmitted to the injection pump IP via the signal line Lo so as to forcibly stop the fuel injection.
[0028]
According to the abnormal blow-up prevention device and the control method for the engine of the present embodiment having the above-described configuration and control method, even if an abnormality occurs in the low-by gas separation device (not shown) and the oil in the blow-by gas cannot be separated, The situation can be quickly grasped by the information from the sensor, and the engine can be forcibly stopped before the engine "abnormally blows up" to prevent a serious accident from occurring.
[0029]
Further, the configuration of the compression pressure release type brake B is based on an auxiliary braking technique proposed by the present applicant, so-called "EEB (trade name, manufactured by Nissan Diesel Industry Co., Ltd.), in which the exhaust valve is slightly opened from the compression process to the expansion process of the engine. The valve development mechanism that discharges the compressed air to the outside of the combustion chamber and effectively pulls out the engine brake by reducing the acceleration force of the piston in the expansion process can be used. Does not occur.
[0030]
The return (start of operation) of the engine can be easily performed by turning on the ignition.
[0031]
The illustrated embodiment is merely an example, and does not limit the technical scope of the present invention. For example, a pressure sensor may be used instead of the rack sensor of the embodiment. In the case of a supercharged engine, a boost pressure sensor may be used instead of the air flow meter.
[0032]
【The invention's effect】
The operation and effect of the present invention will be described below.
(A) Even if an abnormality occurs in the low-by gas separation device and the oil in the blow-by gas cannot be separated, the situation can be quickly grasped by the information from various sensors, and the engine is forced to operate before the "abnormal blow-up" occurs. Since the engine is stopped temporarily, it is possible to prevent the occurrence of a serious accident beforehand.
(B) The configuration can use an existing auxiliary brake technology, for example, a so-called “EEB mechanism” proposed by the present applicant, so that there is no new development cost.
(C) The return of the engine can be easily performed by turning on the ignition.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.
FIG. 2 is a control flowchart showing a control method according to the first embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Cylinder head 3 ... Exhaust port 4 ... Exhaust valve 5 ... Rocker arm 6 ... Rocker shaft 7 ... Push rod 8 ... Cam 9 ... Hydraulic actuator 10 ... Engine controller 11 Rack sensor 12 Air flow meter 13 Exhaust temperature sensor 14 Engine rotation sensor 20 Eccentric bush B ... Compression pressure release type brake IP Injection pump (In-line pump)

Claims (2)

An abnormal blow-up prevention device for a vehicle engine provided with a compression pressure release type brake that is an engine brake, comprising: a fuel injection amount detection unit; an intake air amount detection unit and / or an intake pressure detection unit; An engine rotation sensor, and control means, the control means having a fuel injection amount equal to or less than a predetermined value, an intake air flow rate and / or intake pressure equal to or more than a predetermined value, and an exhaust gas temperature equal to or more than a predetermined value; And an engine abnormal blow-up prevention device, wherein when the engine speed is equal to or higher than a predetermined value and the engine is continuously operated for a predetermined time or more, the compression pressure release type brake is operated to forcibly stop fuel injection. . Determining whether the fuel injection amount is equal to or less than a predetermined value based on information from the fuel injection amount detecting means; and determining whether the intake air amount is equal to or more than the predetermined amount based on information from the intake air amount detecting means. And / or a step of determining whether the intake pressure is equal to or higher than a predetermined value based on information from the intake pressure detecting means, and a step of determining whether the exhaust temperature is equal to or higher than the predetermined value based on information from the exhaust temperature detecting means. And a step of determining whether or not the engine speed has been continuously operated for a predetermined time or more at a predetermined value or more based on information from the engine rotation sensor, and A predetermined value or less, an intake air flow rate is a predetermined value or more, and / or an intake pressure is a predetermined value or more, an exhaust temperature is a predetermined value or more, and an engine speed is a predetermined value or more and a predetermined time or more. Place where it was driven continuously To the actuate the compression pressure open type brake, engine abnormality racing prevention control method and controls to forcibly stop the fuel injection.

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