JPS6012893Y2 - Abnormality detection device for supercharged engines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an abnormality detection device for an engine that includes an exhaust turbo supercharger and an exhaust bypass device that bypasses exhaust gas to the turbine of the supercharger.

As shown in Fig. 1, in an engine with an exhaust turbo supercharger having an exhaust bypass device, a turbine 21 of an exhaust turbo supercharger 2 is rotated by exhaust gas from an engine 1, and a compressor 22 directly connected to the turbine 21 pressurizes the air. The fuel is supplied to the engine 1.

Then, as shown in Fig. 3, the specified engine rotation speed N
When the load exceeds the diaphragm 31, the exhaust bypass device 3 uses the supercharging pressure acting on the diaphragm 31 to
2, the bypass valve 33 is operated to open the bypass passage 3.
4 is opened and a part of the exhaust gas flowing into the turbine 21 is bypassed, and the rotation of the turbine 21, that is, the supercharging pressure by the compressor 22 is controlled to be maintained at a substantially constant value as shown in FIG.

Incidentally, since the exhaust pressure increases approximately in proportion to the square of the engine rotation, if the exhaust bypass device 3 fails and does not open the bypass passage 34, the pressure increases as indicated by the two-dot chain line in FIG. As a result, the boost pressure increases, the explosion pressure increases more than necessary, and the durability of the engine is significantly shortened.

In addition, if the shaft or bearing of the exhaust turbo supercharger 2 is worn out and does not rotate smoothly, and the boost pressure does not reach the specified value as shown by the dotted line in Figure 1, the fuel injection amount should be adjusted. Since the amount of air is insufficient, not only will black smoke be generated, but the exhaust temperature will rise, causing engine seizure.

The present invention aims to prevent engine damage by issuing a warning in the event of an excessive rise in boost pressure due to a failure of the exhaust bypass device or an excess or deficiency in boost pressure due to deterioration of the exhaust turbocharger. , Figures 1 and 2
The invention will be explained by way of an embodiment shown in the figure.

The exhaust gas from the exhaust pipe 11 of the engine 1 rotates the turbine 21 of the exhaust turbo supercharger 2, and the compressor 22 directly connected to the turbine 21 via the shaft 23 pressurizes air and supplies it to the engine 1 via the intake pipe 12. do.

- Exhaust pipe 1.1 receives supercharging pressure from intake pipe 12 through diaphragm 31, and the pressure is applied to spring 32.
An exhaust bypass device 3 is installed that operates a bypass valve 33 to release a part of the exhaust gas from the bypass passage 34 without flowing into the turbine 21 when the biasing force exceeds the biasing force.

The above is an engine with an exhaust turbo supercharger equipped with a normal exhaust bypass device, and in the present invention, it is equipped with an engine shaft rotation detection device 4, a load detection device 6'j5, and a pressure detection device 7. These output signals are supplied to the controller.As shown in FIG. - The voltage converter 4b is compared with the comparator 4C which outputs an output when the voltage exceeds the set value (rotation N), and the load detection device 6 similarly detects the position of the control rack 51 of the injection pump 5. It consists of a rack sensor 61 for detection, a position-voltage converter 6b, and a comparator 6c that outputs an output when this value exceeds a set value (load L). Pressure sensor that detects supply pressure.

7a, a pressure-voltage converter 7b, a first comparator IC that outputs when this value is equal to or higher than a first set value (pressure Plζ, FIG.・Setting value (
The second comparator 7 outputs when the pressure P2, Fig. 3) or less.
The output signals from the comparators 4c and 6c are supplied to the AND circuit 8a of the controller 8. , □8C - And when the AND circuit 8b is supplied with the signal from the AND circuit 8a and the first comparator 7c, the resistor 8d is supplied.

A first alarm device such as a warning lamp 9a is turned on (activated) via a transistor 8e, and when a signal is supplied from an AND circuit 8a and a second comparator 7d, an AND circuit 8C turns on a resistor 8f, A second alarm device, such as a warning lamp 9b, is turned on (activated) via the transistor 8g.

Note that 10 is a power source. The present invention is constructed as described above, and when the exhaust turbo supercharger 2 and the exhaust pipe NO gas device 3 are operating normally, the engine speed and load exceed the set values N and L. Even if this happens, the exhaust bypass device 3 operates the bypass valve 3''3 to allow the exhaust gas to flow out, so that the boost pressure is maintained at a substantially constant reference value P as shown in Figure 3. , and the first and second alarm lamps 9at9b do not light up.

Next, if the exhaust bypass device 3 fails and the bypass path 34 cannot be opened even if the engine shaft rotation and load reach the set value N,i', the condition is 1. The same device 3. rose.

When the reference value P exceeds 21, which is set a little higher than the reference value P in consideration of stress and overshoot, etc., an output is output from the comparator 7c, and this output, engine rotation, and load The AND circuit 8b receives the output from the AND circuit 8a, which outputs when the value exceeds the set value N, L, and the first alarm lamp 9a is turned on via the resistor 8d and transistor 8e. Become.

Furthermore, even if the bypass passage 34' remains open due to deterioration of the exhaust turbo supercharger 2 or failure of the exhaust bypass device 3, and the engine speed and load exceed the set engine speed and load, the standard value is adjusted to the standard value in consideration of noise fluctuations, etc., as described above. If the second set supercharging pressure P2, which is set slightly lower than P, is not reached, an output is output from the comparator 7d, and an AND circuit 8c receives this output and an output from the AND circuit 8a. As a result, the second alarm lamp 9b is turned on via the resistor 8f and transistor 8g.

']' Fig. 4 is a system diagram showing the second embodiment, in which the position of the control rack 51 of the injection pump 5, whose protrusion amount changes as the load increases, is detected and the position is equal to or higher than the set load. A load detection device 6' which closes the contact when 1.
A rotation detection device A that detects the position of the flyweight of the pump governor 52 whose opening amount changes as the engine speed increases, and closes the contact when the position is equal to or higher than the set value N. is connected in series to the power source 10, and furthermore, the position of the diaphragm 3/1 of the exhaust bypass device 3 is determined so that the operating amount of the bypass valve 3/3 changes against the spring 32 as the supercharging pressure increases. Detects and closes the contact when its position is equal to or less than the 16th setting [special number equivalent to 1 or more] first pressure switch 7e, which closes the contact, and the first set value P1 or less, which is equal to or less than the first set value P211. .

A pressure detection device T having a second pressure switch 7f arranged in parallel is connected to the rotation detection device 4.

゛Soshite・1. Load detection device 61. rotation detection device 4,
When the first pressure switch 7e series is conductive, the first alarm lamp 9a lights up, and similarly when the second pressure switch series 7f becomes conductive, the second alarm lamp 9b lights up.

Moreover, FIG. 5 is a main part system diagram showing the third embodiment.
(Second) pressure switch 7e, ? A self-holding circuit is constructed using relays R1 and R2 between f and the first (second) alarm lamps 9a and 9b, so that the supercharging pressure can exceed (below) the first (second) setting once. For example, the alarm states are arranged in cascade.

As described above, according to the present invention, the supercharging pressure is detected at an engine rotational speed N and a load above which the exhaust turbo supercharger 2 and the exhaust bypass device 3 start the specified operation under normal conditions. If the value is above the set value, an alarm is issued to indicate a failure of the exhaust bypass device 3 (remains closed), and if it is below the set value, an alarm is issued to indicate the deterioration of the exhaust turbo supercharger 2 or the failure of the bypass device 3 (remains closed). Since the engine is detected as being open (remaining open), it is possible to prevent damage to the engine due to an increase in explosion pressure due to an abnormal increase in supercharging pressure, or engine seizure due to a decrease in the same pressure.

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[Brief explanation of drawings]

Figure 1! A schematic configuration diagram showing an embodiment of the present invention, Part 2'
Figure 3 is an explanatory diagram showing boost pressure with respect to engine speed and load, Figure 4 is a system diagram showing the second embodiment of the present invention, and Figure 5 is the third embodiment of the same. It is a main part system diagram which shows an example. 1... Engine, 2... Exhaust turbo supercharger, 21... Turbine, 3... Exhaust bypass device, 4... Engine rotation detection device,
6...Load detection device, 7...Supercharging pressure detection device, 9at9b...Alarm (alarm lamp).

Claims (1)

[Scope of utility model registration request] In an engine equipped with an exhaust turbo supercharger having a turbine and a compressor, and an exhaust bypass device that bypasses part of the exhaust gas flowing into the turbine, the rotational speed and load of the engine are detected. A rotation and load detection device that outputs an output when a value is above a set value, and a second set value that detects boost pressure and when the value is above a first set value and is lower than the first set value. What is claimed is: 1. An abnormality detection device for a supercharged engine, comprising: a pressure detection device that outputs an output at the following times; and an alarm is activated when all of the detection devices output.