JPH0334814B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is applicable to a test engine in which engine trouble occurs during a performance test of a test engine in which a DC dynamometer is connected to the test engine to check output characteristics, durability characteristics, etc. The present invention relates to a device for quickly stopping an engine when an engine is damaged.

[Conventional technology]

In order to examine various performances of the test engine,
As shown in the figure, a DC dynamometer 4 is connected to the output shaft of the engine under test 2 to a drive shaft, and the main circuit of the dynamometer 4 is connected to an AC power source 8 via a thyristor unit 6 having an AC/DC conversion function. By connecting the engine 2 to the engine 2 and causing the DC dynamometer 4 to perform an absorption operation, you can conduct an output test to check the engine output and torque with respect to the engine rotation speed, and perform an output test on the engine 2.
A durability test is conducted to determine how much continuous high-speed, high-load operation the engine can withstand, or a friction horsepower test is conducted to determine the horsepower loss due to friction by driving the DC dynamometer 4 and running the engine 2. It's summery.

As a countermeasure in the event that engine trouble occurs during these engine performance tests, for example during an output test, the emergency Press the stop switch ES and turn on the DC dynamometer 4.
At the same time, the throttle valve of the engine 2 is closed to stop the DC dynamometer 4 and the engine 2.

However, if the engine misfires due to a blockage in the engine's fuel system, etc., even if the engine output decreases, it will not appear as engine overspeed, and conventionally, it is not possible to stop the engine immediately after engine trouble occurs. I couldn't do it.

[Problem that the invention seeks to solve]

The thyristor unit 6 is also provided with a constant speed control mechanism 6A, which controls the main circuit voltage and field current of the DC dynamometer 4 according to the rotational speed detection signal from the rotational speed detector 7. The rotational speed of the DC dynamometer 4 is kept constant regardless of the output. Therefore, for example, engine trouble such as a misfire may occur during an output test of engine 2.
Even if the output of the engine 2 is completely lost or significantly reduced, the constant speed control mechanism 6 of the thyristor unit 6
A works, the DC dynamometer 4 shifts from absorption operation to drive operation, the rotational speed of the DC dynamometer 4 is kept constant, and the engine 2 continues to be rotated in a misfire state by the DC dynamometer 4. Become. Therefore, in the engine 2, unburned gas is sent to the exhaust side, and this unburned gas ignites and explodes on the exhaust side, causing damage to the engine 2.

The present invention has been made in view of the above-mentioned problems, and its purpose is to provide an emergency stop device for a test engine that can quickly stop the engine when engine trouble occurs during a performance test of the test engine. It's about doing.

[Means for solving problems]

The engine emergency stop device for the test engine performance test according to the present invention is connected between a DC dynamometer connected to the test engine, the main circuit of the DC dynamometer, and an AC power source, and has an AC/DC conversion function. A thyristor unit that enables the DC dynamometer to perform absorption operation and driving operation, and also controls the DC dynamometer at a constant speed, a current detector installed in the main circuit of the DC dynamometer, and this current detector. detects a drive current, and when the drive current exceeds a set value, the interlock circuit stops the test engine together with the DC dynamometer via the thyristor unit. This aims to achieve the above objectives.

[Effect]

According to the present invention, when the engine output suddenly decreases due to an engine misfire or the like during absorption operation of the DC dynamometer, the DC power is transferred from the external AC power source through the thyristor unit incorporating a constant speed control mechanism. Power is supplied to the main circuit of the meter, and the DC dynamometer shifts to driving operation. At this time, the current detector installed in the main circuit of the DC dynamometer detects the current for driving the DC dynamometer (hereinafter referred to as driving current), and when this driving current exceeds the setting. Occasionally, an interlock circuit is activated to stop the rotation of the test engine along with the DC motor.

[Example] Next, an example of the present invention will be described based on the drawings.

FIG. 1 shows an overall schematic diagram of an embodiment of the present invention.

In this figure, the output shaft 2 of the test engine 2
The rotational drive shaft 4A of the DC dynamometer 4 is connected to A,
A main circuit 5 of the DC dynamometer 4 is connected to an AC power source 8 via a thyristor unit 6 that performs an AC/DC conversion function. The thyristor unit 6 is equipped with a constant speed control device 6A for keeping the rotational speed of the DC wattmeter 4 constant regardless of the output of the engine 2. Shift from operation to drive operation and DC wattmeter 4
rotates the engine 2, and controls the rotational speed of the DC dynamometer 4 regardless of the output of the engine 2 by controlling the main circuit voltage of the DC dynamometer 4 by controlling the delay angle of the main thyristor and controlling the field current by the field thyristor. It is designed to remain constant.

A current detector 10 is provided in the main circuit 5 of the DC dynamometer 4, and this current detector 10 is connected to the comparator 1.
2 to an interlock circuit 20. The comparator 12 is provided with a setting device 14, which compares the detected current signal sent from the current detector 10 with a setting value preset by the setting device 14, and determines whether the detected current is a drive current or not. and the detected current signal is higher than the set value, the interlock circuit 2
It is set to be output as 0. Although the setting value set by the setting device 14 can be arbitrarily determined,
It is desirable that the rotational speed of the engine 2 during idling operation be set to a value with some margin.

As shown in FIG. 2, the interlock circuit 20 is comprised of an interlock exclusion selector 22, a step feed timer 24, and an interlock operation output section 26. The interlock exclusion selector 22 is designed to select the open state of the contact so that the interlock operation output section 26 does not operate when the engine 2 is initially rotated in a driving operation such as in a friction horsepower test. Depending on the type of test, you can choose any option before starting the test. In addition, when the rotational speed of the engine 2 is increased in steps as in the exhaust gas durability pattern test, the engine output is insufficient immediately after the step change to obtain the rotational speed after the step change. , a driving current momentarily flows through the main circuit 5 of the DC dynamometer 4. In such a case, the step feed timer 24 can be set to keep the contacts open for an arbitrary period of time (several seconds) so that the interlock operation output section 26 will not operate. The interlock operation output section 26 outputs an excitation release signal to the electromagnetic contactor that is provided in the DC dynamometer speed setting circuit in the thyristor unit 6 and is self-maintained by excitation, thereby stopping the supply of gate current to the main thyristor. This applies regenerative braking to the DC dynamometer 4 and outputs a signal to close the throttle valve of the engine 2. This causes the DC dynamometer 4 to stop rapidly.

FIG. 3 shows an operation flowchart of the emergency stop device for the test engine according to this embodiment.

In this figure, first in step A, the current detector 10 detects the current flowing through the main circuit 5 of the DC dynamometer 4 and outputs it to the selector 12. Next, as a B step, when the current flowing through the main circuit 5 is a drive current and is greater than or equal to a value preset by the setter 14, the selector 12 outputs it to the interlock exclusion selector 22, and the process moves to the next C step. On the other hand, when the current flowing through the main circuit 5 is a drive current and is not higher than the set value, that is, when the current flowing through the main circuit 5 is not a drive current, or even if it is a drive current, it is lower than the set value. Then, return to step A.
In the C step, the interlock exclusion selector 22
It is determined by ON-OFF, and when it is ON, it returns to step A, and when it is OFF, it goes to the next step.
Move to step. At the D step, it is determined whether or not the step feed timer 24 has timed up. If the time is up, the step moves to the next E step and an interlock is activated.
Before time-up, the process returns to step A.

As described above, according to this embodiment, when the output of the engine 2 significantly decreases due to a misfire or seizure of the test engine 2, the engine 2 can be automatically and promptly stopped together with the DC dynamometer 4. Can be done. Also, the interlock exclusion selector 22
By turning ON, automatic operation of the interlock can be avoided depending on the type of performance test of the test engine, so there is no problem when performing a drive operation in advance like a friction horsepower test.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, if the engine output significantly decreases due to trouble with the test engine, the engine can be automatically and promptly stopped.
Excessive damage to the engine can be prevented.

[Brief explanation of the drawing]

FIG. 1 is an overall schematic diagram of an embodiment of the present invention, FIG. 2 is an interlock operation circuit diagram thereof, FIG. 3 is an operation flowchart thereof, and FIG. 4 is a conventional emergency stop device for a test engine. 2... Test engine, 4... DC dynamometer, 5
... Main circuit of DC dynamometer, 6 ... Thyristor unit, 6A ... Constant speed control device, 7 ... Rotation speed detector, 8 ... AC power supply, 10 ... Current detector,
12... Comparator, 20... Interlock circuit, 2
2...Interlock removal selector, 24...Step feed timer.

Claims (1)

[Claims] 1. A DC dynamometer connected to the engine under test, and a device connected between the main circuit of this DC dynamometer and an AC power source, which has an AC/DC conversion function, and allows the DC dynamometer to perform absorption operation and driving operation. At the same time, a thyristor unit that controls the DC dynamometer at a constant speed, a current detector installed in the main circuit of the DC dynamometer, and this current detector detects the drive current, and when the drive current exceeds the set value. An engine emergency stop device for use in a test engine performance test, comprising: an interlock circuit that stops the test engine together with the DC dynamometer via the thyristor unit in the event of a test.