CN108590865B

CN108590865B - Variable volume diesel engine and working method thereof

Info

Publication number: CN108590865B
Application number: CN201810386260.5A
Authority: CN
Inventors: 张卫波; 朱清; 杨际福; 刘丰; 林镇北; 梁昆; 寿磊
Original assignee: Fuzhou University
Current assignee: Fuzhou University
Priority date: 2018-04-26
Filing date: 2018-04-26
Publication date: 2020-05-08
Anticipated expiration: 2038-04-26
Also published as: CN108590865A

Abstract

The invention relates to a variable volume diesel engine based on a worm gear mechanism and a working method thereof, and the variable volume diesel engine comprises a cylinder with an air inlet pipe and an air outlet pipe, wherein lower tooth blocks protruding upwards are distributed at intervals on the top of a piston in the cylinder, a floating plate capable of moving up and down is arranged above the cylinder, upper tooth blocks penetrating through the top of the cylinder and extending into the cylinder are distributed at intervals on the lower side of the floating plate, the positions of the upper tooth blocks and the lower tooth blocks are staggered, the upper tooth blocks can be inserted into lower tooth grooves between two adjacent lower tooth blocks when the piston moves upwards, and the lower tooth blocks can be inserted into upper tooth grooves between two adjacent upper tooth blocks. The invention can control and adjust the compression ratio according to the different compression ratios required under various load working conditions, so that the compression ratio of the diesel engine is most consistent with the current working condition, fuel can be fully atomized and combusted under various working conditions, knocking is avoided, and the best effects of fuel economy, dynamic property and emission are achieved.

Description

Variable volume diesel engine and working method thereof

Technical Field

The invention relates to a variable volume diesel engine, belonging to the technical field of vehicle dynamic property and economy.

Background

With the increasing strictness of emission regulations and the demands of customers on engine economy, improving the power performance and fuel economy performance of engines has been the biggest difficulty faced by conventional internal combustion engines. At present, the engine mainly adopts a three-way catalyst for changing emission and mainly adopts in-cylinder direct injection and variable valve technology for improving fuel economy performance. To further reduce emissions, new combustion modes are now emerging. These new combustion modes are primarily aimed at low temperature combustion and homogeneous mixture formation, i.e., low charge temperature and homogeneous mixture, as well as lower compression ratio to reduce NOX and PM emissions. In order to realize the low-temperature combustion technology in the full-load working condition range, the application of the variable compression ratio technology is necessary.

At present, the compression ratio of most engines is fixed, the air intake charge is small at low rotating speed, the actual compression ratio is lower than the designed compression ratio, and the fuel cannot be atomized and combusted fully. When the engine is in high rotating speed or the turbocharger is introduced, the air filling amount in the cylinder is larger than the volume in the cylinder, and the actual compression ratio is higher than the designed compression ratio, so that knocking and advanced combustion are easily generated, the power output is greatly reduced, and the damage to the engine is increased.

Disclosure of Invention

In view of the above, the present invention provides a variable volume diesel engine.

The invention is realized by adopting the following scheme: the utility model provides a variable volume diesel engine, is including taking the cylinder of intake pipe and blast pipe, and the top interval distribution of piston has the bellied lower tooth piece that makes progress in the cylinder, and the cylinder top is provided with the floating plate that can reciprocate, floating plate downside interval distribution passes and stretches into the last tooth piece to the cylinder inside by the cylinder top, goes up the position of tooth piece and staggers and go up the tooth piece when the piston goes upward and can insert in the lower tooth's socket between the adjacent two lower tooth pieces, lower tooth piece can insert in the last tooth's socket between the adjacent two upper tooth pieces.

Furthermore, a screw rod in rotary fit with the floating plate is vertically arranged above the floating plate, a worm wheel in threaded fit with the screw rod is sleeved on the screw rod, the worm wheel is matched with a worm, and the worm is coaxially connected with a rotating shaft of a stepping motor.

The stepping motor control system further comprises a throttle opening sensor used for sensing the throttle opening and a crankshaft rotating speed sensor used for sensing the rotating speed of the crankshaft, wherein the throttle opening sensor and the crankshaft rotating speed sensor are both connected with the ECU, and the ECU is connected with a driving circuit of the stepping motor.

A variable volume diesel engine working method, adopt the above-mentioned variable volume diesel engine, when the diesel engine is in the low-load at present, start, heat engine, etc. state, control the upper tooth piece to move downward with the floating plate, increase the compression ratio; when the diesel engine is in the states of high working condition, full load and the like, the upper tooth block is controlled to move upwards along with the floating plate, and the compression ratio is reduced.

Compared with the prior art, the invention has the following beneficial effects: the invention can control and adjust the compression ratio according to the different compression ratios required under various load working conditions, so that the compression ratio of the diesel engine is most consistent with the current working condition, fuel can be fully atomized and combusted under various working conditions, knocking is avoided, and the best effects of fuel economy, dynamic property and emission are achieved.

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to specific embodiments and accompanying drawings.

Drawings

FIG. 1 is a schematic construction of an embodiment of the present invention;

the reference numbers in the figures illustrate: 1-throttle opening sensor, 2-ECU, 3-crankshaft speed sensor, 4-stepping motor, 5-worm, 6-air inlet pipe, 7-exhaust pipe, 8-cylinder, 9-worm wheel, 10-piston, 11-lower gear block, 12-upper gear block, 13-screw rod, 14-floating plate.

Detailed Description

As shown in fig. 1, a variable volume diesel engine comprises a cylinder 8 with an air inlet pipe 6 and an exhaust pipe 7, wherein fuel gas in the cylinder 8 is exhausted through the exhaust pipe 7 through a piston 10 during an exhaust stroke, lower tooth blocks 11 protruding upwards are distributed at intervals on the top of the piston 10 in the cylinder 8, a floating plate 14 capable of moving up and down is arranged above the cylinder, upper tooth blocks 12 penetrating through the top of the cylinder and extending into the cylinder are distributed at intervals on the lower side of the floating plate 14, the positions of the upper tooth blocks 12 are staggered with those of the lower tooth blocks 11, the upper tooth blocks can be inserted into lower tooth grooves between two adjacent lower tooth blocks when the piston moves upwards, the lower tooth blocks can be inserted into upper tooth grooves between two adjacent upper tooth blocks, and strip-shaped holes for the upper tooth blocks to penetrate and to be in sealing fit with the upper tooth blocks are formed in the top of the cylinder 8; when the piston moves upwards, the upper tooth block and the lower tooth block are meshed, the position of the upper tooth block 12 is changed on the premise that the free stroke of the piston 10 is not changed, namely, the length of the upper tooth block extending into the cylinder is changed, the degree of the upper tooth block and the lower tooth block meshed with each other is changed, the volumetric compression ratio is adjusted, fuel can be fully atomized and combusted under various working conditions, knocking is avoided, the fuel economy and the dynamic performance are improved, and emission is effectively reduced.

In the embodiment, a screw rod 13 rotatably matched with the floating plate 14 is vertically arranged above the floating plate, a worm wheel 9 in threaded matching with the screw rod is sleeved on the screw rod, the worm wheel 9 is matched with a worm 5, and the worm 5 is coaxially connected with a rotating shaft of the stepping motor 4.

In this embodiment, the system further comprises a throttle opening sensor 1 for sensing the opening of the throttle valve and a crankshaft rotation speed sensor 3 for sensing the rotation speed of the crankshaft, the crankshaft rotation speed sensor 3 is disposed on the crankshaft of the diesel engine, the throttle opening sensor 1 is disposed at an accelerator pedal for real-time monitoring of the operating condition of the diesel engine, the throttle opening sensor and the crankshaft rotation speed sensor are both connected to an ECU2, the ECU2 is a central control unit of an electronic control system, the ECU2 is connected to a driving circuit of the stepping motor 4, and the throttle opening sensor and the crankshaft rotation speed sensor are used for detecting corresponding diesel engine operating condition data to indirectly obtain the current operating condition of the diesel engine.

When the ECU2 detects that the diesel engine is in the states of low load, starting, heating and the like at present, the stepping motor 4 rotates positively to control the upper tooth block to move downwards along with the floating plate, so that the compression ratio is increased, the in-cylinder combustion is more sufficient, the PM is reduced, and the dynamic property and the heat engine efficiency of the diesel engine are improved; when the ECU2 detects that the diesel engine is currently in the states of high working condition, full load and the like, the stepping motor 4 rotates reversely, the upper tooth block is controlled to move upwards along with the floating plate, the compression ratio is reduced, the load and detonation probability of the diesel engine is reduced, the rotational inertia is improved, the economy is improved, the in-cylinder volume of the engine is improved, the in-cylinder pressure is reduced, the in-cylinder temperature is reduced, and the emission of NOX is reduced.

In the range of not generating knock, the compression ratio is improved as much as possible, and the fuel economy and the dynamic property can be improved by a lean combustion technology. When the engine runs at low load, the information of the throttle position sensor 1 and the crankshaft speed sensor 3 is processed by the ECU2, and the compression ratio is properly reduced by the working principle to realize the low-temperature combustion technology under all working conditions, so that the emission of NOX, PM and the like is reduced, and the aims of reducing the fuel consumption and reducing the harm of pollution emission are achieved

The above-mentioned preferred embodiments, further illustrating the objects, technical solutions and advantages of the present invention, should be understood that the above-mentioned are only preferred embodiments of the present invention and should not be construed as limiting the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A variable volume diesel engine comprising a cylinder with an inlet pipe and an exhaust pipe, characterized in that: the top interval distribution of piston has the bellied lower tooth piece that makes progress in the cylinder, and the cylinder top is provided with the floating plate that can reciprocate, floating plate downside interval distribution is passed and is stretched into the inside last tooth piece of cylinder by the cylinder top, goes up the position of tooth piece and stagger with the position of tooth piece down and go up the tooth piece and can insert in the lower tooth's socket between two adjacent lower tooth pieces, lower tooth piece can insert in the last tooth's socket between two adjacent last tooth pieces when the piston goes upward.

2. A variable volume diesel engine as claimed in claim 1, wherein: the upper part of the floating plate is vertically provided with a screw rod which is in rotary fit with the floating plate, the screw rod is sleeved with a worm wheel which is in threaded fit with the screw rod, the worm wheel is matched with a worm, and the worm is coaxially connected with a rotating shaft of a stepping motor.

3. A variable volume diesel engine as claimed in claim 2, wherein: the throttle opening sensor and the crankshaft rotating speed sensor are both connected with an ECU, and the ECU is connected with a driving circuit of the stepping motor.

4. A method of operating a variable volume diesel engine using the variable volume diesel engine according to claim 1, characterized in that: when the diesel engine is in the low-load, starting and heat engine states at present, the upper gear block is controlled to move downwards along with the floating plate, and the compression ratio is increased; when the diesel engine is in a high working condition and full load state, the upper tooth block is controlled to move upwards along with the floating plate, and the compression ratio is reduced.