JPH0749403Y2 - Fault diagnosis system for hydraulically driven exhaust valves - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a hydraulically driven exhaust valve device for a diesel engine.

[Conventional technology]

Conventionally, the abnormality of the opening / closing timing caused by the malfunction of the exhaust valve is judged by comparing with the in-cylinder acupressure diagram at the normal time. FIG. 4 shows an example thereof. In the figure, the solid line shows the normal state, the dotted line shows the case where the compression pressure drops due to the valve opening timing abnormality, and the dashed-dotted line shows the case where the combustion does not occur due to the valve opening timing abnormality.

[Problems to be solved by the device]

However, the in-cylinder pressure may change due to defective operation of the exhaust valve, but other than that, there may be fuel fluctuation due to defective fuel valves or fluctuations in the supply conditions, and there may be cases where the compression pressure drops due to gas leakage. As described above, the in-cylinder pressure is governed by various factors, and it is very difficult to identify the abnormality of the exhaust valve based on the change in the in-cylinder pressure. In addition, it is more difficult to continuously measure the in-cylinder pressure than the durability of the pressure sensor. In addition, exhaust valve abnormalities may cause a slight decrease in output due to deterioration of combustion, or may cause a major accident such as explosion in the exhaust pipe due to non-ignition of fuel.The operating condition of each cycle is monitored to determine the degree of abnormality quantitatively. It is important to detect at.

An object of the present invention is to solve the above problems of the conventional device and to quantitatively detect the abnormality of the opening / closing valve timing due to defective operation of the exhaust valve of the hydraulically driven exhaust valve device on the basis of the crank angle so that the engine operation can be continued. (EN) It is possible to provide a failure diagnosis device for a hydraulically driven exhaust valve capable of determining whether the failure is a minor one or a serious one that requires an emergency stop.

[Means for Solving the Problems]

The hydraulic drive type exhaust valve failure diagnosing device of the present invention includes a hydraulic pressure sensor for measuring the drive hydraulic pressure of each exhaust valve driving hydraulic cylinder, a TDC sensor for detecting a reference position of a crank angle, and a partition of an exhaust valve drive hydraulic pressure curve. A pulse converter that converts the exhaust valve opening / closing timing at the point of hydraulic pressure Pv into a pulse signal, a pulse converter that converts the output of the crank angle sensor into a pulse signal, and the opening / closing timing based on both pulses from both converters. And a comparator for comparing the opening / closing timing measured and calculated for each engine cylinder with each cylinder and with reference data.

[Action]

FIG. 2 (a) is a drive oil pressure curve, and the opening / closing timing is obtained from the opening / closing valve pressure Pv. The opening / closing hydraulic pressure of the exhaust valve varies depending on the specifications of the hydraulic system and the exhaust valve device, but the same engine has the same pressure value Pv for all cylinders. The valve opening timing obtained as the opening / closing valve pressure partition value is pulse-converted. Note that this partition value may be another pressure value.

Next, the valve opening timing Tvo and the valve closing timing Tvc are known from the time difference from the separately input TDC pulse. On the other hand TDC
From the pulse interval Tn, the engine speed Ne, the crank angles θvo and θvc of the opening / closing valve timing, and the valve opening period θ are also known.

The right side of FIG. 2 shows the case where the valve opening timing is delayed for some reason in the same cylinder. In such a case θvo
And θv ₁ , θvc and θvc ₁₁ , and θ and θ 1 are compared, the abnormality can be detected quantitatively. By constantly comparing θvo, θvc, and θ with other cylinders, it is possible to cope with changes in the opening / closing valve timing due to fluctuations in rotation speed and the like.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is an overall configuration diagram.

Reference numeral 1 is an engine body, 200a to 200e are exhaust valve boxes installed in each cylinder, 3 is a flywheel, 4a to 4e are sensors for measuring the driving hydraulic pressure of each cylinder, and 5 is a TD from the flywheel 3.
A sensor for detecting the C position, 6 is a pressure converter, 7 is a pulse converter that converts the opening / closing valve timing into a pulse signal from the driving oil pressure, 8 is a pulse converter that converts the input from the TDC sensor 5 into a pulse signal, 9 Is an arithmetic unit for calculating the opening / closing valve timing from the outputs of the pulse converters 7, 8, 10 is a data comparator, and 11 is an indicator for displaying an abnormal state.

Next, the operation of the above embodiment will be described.

The drive oil pressure curve is shown in FIG. Here, the opening / closing valve oil pressures of the exhaust valves have the same pressure value Pv for all cylinders in the same engine. First, the exhaust valve opening / closing timing at the point where the exhaust valve driving hydraulic pressure becomes the specific partition hydraulic pressure is converted into a pulse signal as shown in FIG. 2 (b). The partition value may be another pressure value.

Next, the valve opening timing Tvo and the valve opening timing Tvc are known from the time difference from the separately input TDC pulse of FIG. 2 (c). On the other hand, the engine speed Ne, the crank angles θvo and θvc of the opening / closing valve timing, and the valve opening period θ are also known from the TDC pulse interval Tn.

The right side of FIG. 2 shows an example in which the valve opening timing is delayed for some reason in the same cylinder. Such θvo
And by comparing θv ₁ , θvc with θvc ₁ , and θ with θ ₁ , the abnormality can be quantitatively detected. By constantly comparing θvo, θvc, and θ between other cylinders, it is possible to cope with changes in the opening / closing valve timing due to fluctuations in the rotational speed.

FIG. 3 shows a flow chart of the failure diagnosis device of this device.

Initially, reference data of the exhaust valve opening / closing timing according to the initial conditions such as the variation allowable value between cylinders and the engine speed are input in advance.

Next, each time of Tvo, Tvc, and Tn is measured for each cycle of each cylinder. Engine speed N from measured Tvo, Tvc, Tn
e, and the crank angles θvo and θvc of the opening / closing valve timing are calculated, and θvo and θvc between the cylinders are compared. Judge as abnormal. The abnormal cylinder is judged by comparing with the reference data. If the crank angles θvo and θvc of the opening / closing valve timing are within the permissible values for each cylinder, the presence / absence of abnormality in each cylinder common device is compared with the reference data. When an abnormality is detected, it is determined whether the engine is stopped or the operation is continued depending on the degree of the abnormality. When the operation is stopped, the abnormality is displayed.

[Effect of device]

The present invention is configured as described above, and the abnormality of the opening / closing valve timing due to the malfunction of the exhaust valve can be quantitatively detected on the basis of the crank angle.Therefore, the engine operation should be mild or an emergency stop is required. It is possible to judge whether the failure is serious or not. Further, since the monitoring is performed for each cycle, it is possible to detect not only the sudden exhaust valve failure but also the case where the precursor of the exhaust valve failure is intermittently displayed.

Further, since the determination of the operation can be performed by comparing the data with other cylinders, the determination can be easily performed even in a transient state such as a rapid rotation speed change that is difficult to determine by comparing only the reference data.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 to FIG. 3 relate to the present invention. FIG. 1 is an overall configuration diagram of the first embodiment, FIG. 2 is a relational diagram of drive hydraulic pressure and opening / closing valve timing, and FIG. FIG. 4 is a flow chart of an embodiment, and FIG. 4 is an acupressure diagram drawn by a conventional exhaust valve failure diagnostic device. 1 ... Engine body, 4a-4e ... Oil pressure sensor, 5 ... TDC sensor, 6 ... Pressure converter, 7 ... Pulse converter, 8 ...
Converter, 9 ... Calculator, 10 ... Data comparator.

Claims (1)

[Scope of utility model registration request] Claim: What is claimed is: 1. A hydraulic pressure sensor for measuring the driving hydraulic pressure of each exhaust valve driving hydraulic cylinder, a TDC sensor for detecting a reference position of a crank angle, and a specific partition hydraulic pressure (P
The pulse converter that converts the exhaust valve opening / closing timing at point v) into a pulse signal, the pulse converter that converts the output of the crank angle sensor into a pulse signal, and the opening / closing timing based on the pulses from both converters. A computing unit to calculate,
A failure diagnosis device for a hydraulically driven exhaust valve, comprising: a comparator that compares the opening and closing timing measured and calculated for each cylinder with each cylinder and with reference data.