CN104251777A - Device and method for detecting combined errors of engine valves - Google Patents

Abstract

The invention provides a comprehensive error detection device and method for an engine valve, which includes a computer, a follow-up probe for detecting the movement of the engine valve lift, a probe support arm for fixing the follow-up probe, and a probe arm for detecting the engine valve lift movement. A circular grating encoder for changing the phase angle of the crankshaft and a positioning support arm for fixing the circular grating encoder. The probe support arm and the positioning support arm are arranged on the casing of the engine, and the follower probe and the circular grating encoding The device is connected with the computer through a data acquisition card. The invention can be used for the comprehensive detection of the valve lift after the engine assembly is completed, avoiding the detection error of the valve lift caused by the processing and assembly errors of parts such as the camshaft, and realizing the engine The detection of the lift error of a single valve, the valve timing error, and the overlap angle error of a group of valves.

Description

Device and method for comprehensive error detection of engine valve

technical field

The invention belongs to the field of precision measurement of complex profiles, and in particular relates to a device and method for comprehensive error detection of engine valves.

Background technique

Engine valves have a great influence on the economy, power, vibration and noise characteristics of the engine.

The main function of the engine valve is to realize the intake and exhaust of the engine cylinder by opening and closing in good time. The opening and closing timing of the engine valve and the duration of the opening and closing state have a great influence on the performance of the engine. Excessive engine valve lift error will cause the engine cylinder intake and exhaust resistance to increase, and the air charge will decrease, which will affect the engine's power performance, or the valve will not close tightly, causing the cylinder to leak, and the working pressure will drop, resulting in a decrease in engine power. In addition, If the valve lift error of the engine is too large, it will also cause insufficient air intake in the cylinder, and the fuel will not be burned completely. The excess fuel will be discharged together with the exhaust gas, and black smoke will appear.

Since the lift of the engine valve is realized by the camshaft, the traditional valve lift detection method is to remove the engine camshaft and detect the profile of each cam on the camshaft, so as to obtain its lift curve, phase parameters and other information. However, due to the wear of the cam, the machining error of the camshaft and tappet and other parts, the assembly error, and the existence of the measurement error of the lift in the actual use process, the measurement result is quite different from the actual lift of the valve.

Contents of the invention

The object of the present invention is to provide a device and method for detecting comprehensive error of engine valves.

To achieve the above object, the present invention adopts the following technical solutions:

An engine valve comprehensive error detection device, the detection device includes a computer, a data acquisition card, a follow-up probe for detecting engine valve lift movement, a probe support arm for fixing the follow-up probe, and a A circular grating encoder for detecting changes in the phase angle of the crankshaft of the engine and a positioning support arm for fixing the circular grating encoder. The probe support arm and the positioning support arm are arranged on the casing of the engine, and one end of the data acquisition card is connected to the The moving measuring head is connected with the circular grating encoder, and the other end is connected with the computer.

The follow-up probe is arranged on the support arm of the probe, and the measuring rod of the follow-up probe presses against the engine valve spring seat, and the measuring rod moves synchronously with the engine valve spring seat through stretching.

The follow-up measuring head includes a measuring head substrate, a linear guide rail, a spring, a slide plate, a measuring rod, a grating ruler and a grating ruler reading head, the measuring head substrate is connected to the probe arm, and the linear guide rail and the grating ruler reading head are arranged on On the probe base plate, the slide plate is set on the linear guide rail, the measuring rod and the grating ruler are set on the slide plate, one end of the spring is connected with the slide plate, and the other end is connected with the base fixed on the probe base plate, and the grating scale reading head passes through the The data acquisition card is connected with the computer.

There are one or more follow-up probes, and the number of follow-up probes is the same as the number of engine valves to be detected.

The detection device also includes a circular grating encoder mounting plate, one end of the circular grating encoder mounting plate is connected to the mounting flange of the circular grating encoder, and the other end is connected to the exposed end of the engine crankshaft.

A method for detecting an engine valve comprehensive error, comprising the following steps:

The crankshaft of the engine is driven manually or by a motor, and the computer collects two detection data synchronously through the data acquisition card. One detection data is the change of the phase angle of the engine crankshaft recorded by the circular grating encoder, and the other detection data is the change of the servo probe. For the lift change information of the engine valve spring seat, the computer calculates the valve lift error and the valve timing error based on the two-way detection data.

The computer converts the change information of the phase angle of the engine crankshaft into the change information of the phase angle of the engine camshaft, and according to the theoretical conversion relationship between the theoretical lift change of the engine camshaft and the lift change of the engine valve, the engine single valve with the engine crankshaft The theoretical lift change information of the phase angle change; the computer obtains the lift error of the single valve of the engine and the valve timing by comparing the lift change information of the engine valve spring seat recorded by the moving probe with the theoretical lift change information. bit error.

The computer also calculates the theoretical overlap angle and the actual overlap angle of a group of engine valves to obtain the overlap angle error of a group of valves.

The beneficial effects of the present invention are reflected in:

The invention can be used for the comprehensive detection of the valve lift after the engine assembly is completed, avoiding the detection error of the valve lift caused by the processing and assembly errors of parts such as the camshaft, and can realize the lift error of the single valve of the engine, the valve distribution Detection of gas phase error and overlap angle error of a group of valves.

Description of drawings

Fig. 1 is the overall structural representation of the present invention;

Fig. 2 is a schematic diagram of the internal structure of the follow-up probe of the present invention;

Fig. 3 is a schematic diagram of the external structure of the servo measuring head according to the present invention;

In the figure: 1 is the simulated engine case, 2 is the follower probe, 3 is the probe support arm, 4 is the circular grating encoder positioning arm, 5 is the circular grating encoder mounting plate, 6 is the installation flange, 7 is a circular grating encoder, 8 is a probe substrate, 9 is a spring, 10 is a high-precision linear guide, 11 is a slide plate, 12 is a high-resolution grating ruler, 13 is a grating ruler reading head, 14 is a measuring rod, and 15 is a Engine valve spring seat, 16 is a base, and 17 is a probe cover plate.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings and embodiments.

Referring to Fig. 1, the engine valve comprehensive error detection device of the present invention comprises computer, data acquisition card, the follow-up probe 2 that is used to detect engine valve lift motion, the probe support arm that is used to fix described follow-up probe 3. The circular grating encoder 7 used to detect the engine crankshaft phase angle change and the positioning support arm (that is, the circular grating encoder positioning support arm 4) for fixing the circular grating encoder, the probe support arm 3 and The positioning support arm is arranged on the casing of the engine, and one end of the data acquisition card is connected with the said moving measuring head 2 and the circular grating encoder 7, and the other end is connected with the computer. The follow-up measuring head 2 is arranged on the measuring head support arm 3, and the measuring rod of the following moving measuring head 2 is pressed against the valve spring seat 15 of the engine valve under test with a certain amount of compression. Seat 15 moves synchronously. The detection device also includes a circular grating encoder mounting plate 5, one end of the circular grating encoder mounting plate 5 is connected with the mounting flange 6 of the circular grating encoder, and the other end is connected with the exposed end of the crankshaft of the engine, and the circular grating encoder is installed The plate can rotate with the crankshaft to realize crankshaft phase change detection.

Referring to Fig. 2 and Fig. 3, the servo probe 2 includes a probe substrate 8 and a probe cover plate 17 (used to be combined with the probe substrate to form a casing of the servo probe to protect other parts of the servo probe) , high-precision linear guide rail 10, spring 9, slide plate 11, measuring rod 14, high-resolution grating ruler 12 and grating ruler reading head 13, the probe substrate 8 is connected with the probe support arm 3, and the high-precision linear guide rail and grating The ruler reading head 13 is set on the probe substrate 8, the slide plate 11 is set on the high-precision linear guide rail, and can move up and down along the high-precision linear guide rail, the measuring rod 14 and the high-resolution grating ruler are set on the slide plate 11, and the spring 9 One end is connected with the slide plate 11, and the other end is connected with the base 16 fixed on the base plate of the measuring head. The grating ruler reading head 13 is connected with the computer through the data acquisition card. When the engine valve spring seat 15 moves, the measuring rod 14 realizes telescopic follow-up through the movement of the slide plate 11 on the high-precision linear guide rail 10 and the action of the spring 9. When the slide plate 11 moves, the grating ruler reading head 13 and the high-resolution grating The ruler 12 cooperates to complete the collection and output of the movement variation of the measuring rod.

There are one or more follow-up probes 2, and the number of follow-up probes 2 is the same as the number of engine valves to be detected, so as to detect multiple valves simultaneously.

The engine valve comprehensive error detection method based on the above-mentioned engine valve comprehensive error detection device comprises the following steps:

The crankshaft of the engine is driven manually or through the motor, and the crankshaft drives the camshaft to rotate. The cam of the camshaft drives the valve up and down through the direct or indirect pressure spring seat. The computer collects two detection data synchronously through the data acquisition card. The change of the phase angle of the engine crankshaft recorded by the grating encoder 7, and the other detection data is the lift change information of the engine valve spring seat recorded by the moving probe 2, that is, the lift change information of the valve. The analysis software system of the computer is based on The two-way detection data calculates the valve lift error and the valve timing error.

Specifically, the computer converts the change information of the phase angle of the engine crankshaft into the change information of the phase angle of the engine camshaft, and obtains the engine single angle according to the theoretical conversion relationship between the theoretical lift change of the engine camshaft and the lift change of the engine valve. The theoretical lift change information of the valve with the change of the engine crankshaft phase angle; since the lift change of the engine valve spring seat is equivalent to the lift change of the engine valve, the computer will record the lift change information of the engine valve spring seat by the follow-up probe Compared with the theoretical lift change information, the lift error and valve timing error of the single valve of the engine are obtained. The analysis software system of the computer also obtains the overlap angle error of a group of valves by calculating the theoretical overlap angle and the actual overlap angle of a group of engine valves.

Example

An engine valve comprehensive error detection device comprises a circular grating encoder, a circular grating encoder mounting plate, a follow-up probe, a probe support arm, a circular grating encoder positioning support arm, and a computer and analysis software system. The mounting flange of the circular grating encoder is installed on the circular grating encoder mounting plate, and the circular grating encoder mounting plate is mounted on the exposed end of the engine crankshaft for measuring the phase angle change of the engine crankshaft under test. The circular grating encoder mounting plate is bolted to the exposed end of the engine crankshaft, so that the rotary center of the circular grating encoder coincides with the rotary center of the engine crankshaft. The circular grating encoder positioning support arm is installed on the engine case for the phase angle positioning of the circular grating encoder to ensure that the circular grating encoder housing does not rotate with the crankshaft during the crankshaft rotation. The probe support arm is fixed on the engine case as the supporting structure of the follow-up probe. The follow-up probe is installed on the probe support arm. on the spring seat.

In the follow-up probe, the grating ruler reading head and high-precision linear guide are placed on the base plate of the probe, the slide plate is placed on the high-precision linear guide, and can move up and down along the high-precision linear guide, and the measuring rod and grating ruler are placed on the slide. , the spring is placed between the base and the slide.

Each set of engine valve comprehensive error detection device can be equipped with multiple sets of follow-up probes and probe support arms according to the number of valves or detection needs, so as to achieve the purpose of simultaneously detecting multiple valve comprehensive errors.

The crankshaft of the engine under test can be rotated manually or driven by a motor. The data collected by the acquisition card is analyzed and processed by the computer analysis software system, and the lift error of a single valve, the valve timing error of the valve, and the overlap angle error of a group of valves are calculated.

During the detection process, the crankshaft is driven manually or by a motor, the crankshaft drives the camshaft to rotate, and the cam of the camshaft drives the valve up and down through direct or indirect pressing against the spring seat. The circular grating encoder records the change of the phase angle of the crankshaft, which is collected by the computer through the acquisition card. At the same time, the lift change information of the spring seat corresponding to the measured valve, that is, the lift change information of the valve, is recorded by the servo probe, and is obtained by The acquisition card realizes the synchronous acquisition with the computer of the phase angle change information. Finally, the analysis software system of the computer realizes the detection of the lift error of a single valve, the valve timing error of a valve, and the overlap angle error of a group of valves.

In actual transmission, the crankshaft drives the camshaft to rotate through a specific transmission ratio, and the lift of the camshaft is transmitted to the engine valve through a specific transmission mechanism. Converted to the phase change of the camshaft, since the spring seat and the valve are rigidly connected, the lift change of the spring seat recorded by the follow-up probe is the lift change of the engine valve.

Because the lift change of the engine camshaft is converted into the lift change of the valve through a certain ratio, through software calculation, the lift change of the camshaft can be converted into the lift change of the valve, combined with the change of the crankshaft phase angle and the camshaft phase The conversion relationship of the angle change can obtain the theoretical lift change information of the valve, and compare it with the actual lift change information to obtain the lift error of a single valve and the valve timing error, and use a group of valve detection data to further calculate The overlap angle error of a group of valves can be obtained.

Claims (8)

1. an engine valve composition error pick-up unit, it is characterized in that: this pick-up unit comprises computing machine, data collecting card, for detecting the servo-actuated gauge head (2) of engine air valve lift motion, for the gauge head support arm (3) of fixing described servo-actuated gauge head, for detecting the disk light beam encoder (7) of engine crankshaft phase angle change and the location support arm for fixing described disk light beam encoder, described gauge head support arm (3) and location support arm are arranged on the casing of engine, one end of data collecting card is connected with described servo-actuated gauge head (2) and disk light beam encoder (7), the other end is connected with computing machine.

2. a kind of engine valve composition error pick-up unit according to claim 1, it is characterized in that: described servo-actuated gauge head (2) is arranged on gauge head support arm (3), the measuring staff top of servo-actuated gauge head (2) is pressed on engine valve spring seat (15), and described measuring staff is synchronized with the movement with engine valve spring seat (15) by flexible.

3. a kind of engine valve composition error pick-up unit according to claim 1 or 2, it is characterized in that: described servo-actuated gauge head (2) comprises gauge head substrate (8), line slideway, spring (9), slide plate (11), measuring staff (14), grating scale and grating ruler reading head (13), gauge head substrate (8) is connected with described gauge head support arm (3), line slideway and grating ruler reading head (13) are arranged on gauge head substrate (8), slide plate (11) is arranged on line slideway, measuring staff (14) and grating scale are arranged on slide plate (11), one end of spring (9) is connected with slide plate (11), the other end is connected with the pedestal be fixed on gauge head substrate (16), grating ruler reading head (13) is connected with computing machine by described data collecting card.

4. a kind of engine valve composition error pick-up unit according to claim 1, is characterized in that: described servo-actuated gauge head (2) is for one or more, and the quantity of servo-actuated gauge head (2) is identical with the engine valve quantity needing to detect.

5. a kind of engine valve composition error pick-up unit according to claim 1, it is characterized in that: described pick-up unit also comprises disk light beam encoder installing plate (5), one end of disk light beam encoder installing plate (5) is connected with the mounting flange (6) of disk light beam encoder, and the other end is connected with engine crankshaft exposed junction.

6. an engine valve composition error detection method, is characterized in that: comprise the following steps:

Manually or rotated by driven by motor engine crankshaft, computing machine detects data by data collecting card synchronous acquisition two-way, the change that data are the phase angle of the engine crankshaft of disk light beam encoder record is detected on one tunnel, the lift variation information that data are the engine valve spring seat of servo-actuated gauge head record is detected on another road, and computing machine detects data according to two-way and calculates valve stroke error and air gate distribution phase error.

7. a kind of engine valve composition error detection method according to claim 6, it is characterized in that: the change information of the phase angle of engine crankshaft is converted to the change information of the phase angle of engine cam by computing machine, and obtain according to the theoretical transformation relation of the theoretical lift variation of engine cam and the lift variation of engine valve the theoretical lift variation information that engine list valve changes with engine crankshaft phase angle; Computing machine compares by the lift variation information of the engine valve spring seat by servo-actuated gauge head record and described theoretical lift variation information the lift range error and air gate distribution phase error that obtain engine list valve.

8. a kind of engine valve composition error detection method according to claim 6, is characterized in that: described computing machine also obtains the angle overlap error of one group of valve by the theoretical angle overlap of calculating one group of engine valve and actual angle overlap.