CN105649756A - Twin-stage supercharged engine with interstage cooler - Google Patents

Abstract

The invention discloses a two-stage supercharged engine with an interstage cooler, comprising a two-stage supercharged system using two turbochargers and a cooling system with an interstage cooler, the two-stage supercharged system Including the air filter, low-pressure stage compressor, interstage cooler, high-pressure stage compressor and intercooler connected to the engine intake manifold, and the high-pressure stage turbine and low-pressure stage turbine connected to the engine exhaust manifold, The high-pressure stage turbine is connected in parallel with the supercharger air release valve; the cooling system includes two parallel cooling circuits for cooling the pre-compressed intake air cooling circuit and the compressed intake air cooling circuit, and the two circuits of coolant are directly taken from the engine water tank for cooling. The two-stage supercharging system of the present invention meets the responsiveness requirements with a small turbine, so that the engine can achieve maximum torque at a relatively low speed, and uses a large turbine to meet high torque requirements. By controlling the ratio of exhaust gas driving the two turbines, it can meet a larger compression ratio. , Large flow rate without generating more pumping loss.

Description

A two-stage supercharged engine with an interstage cooler

technical field

The invention relates to a two-stage supercharged engine, in particular to an engine with an interstage cooler, and belongs to the technical field of automobile engines.

Background technique

With the increasingly serious environmental pollution and energy shortage, countries around the world pay more and more attention to the energy saving and emission reduction of automobiles, and the emission regulations are becoming stricter. High efficiency, energy saving, and environmental protection are the main goals of engine technology development. Turbocharging technology can greatly improve engine power and economy, and reduce pollutant emissions in exhaust gas. The two-stage supercharging technology can significantly increase the power of the diesel engine, improve the low-speed torque of the diesel engine, and reduce emissions and fuel consumption. Therefore, the two-stage supercharging technology has become an important direction in the development of domestic diesel engines. However, while the two-stage supercharging increases the density of the mixed gas, it will inevitably lead to an increase in the temperature of the mixed gas. Low-speed performance is counterproductive, so a two-stage supercharged engine with interstage intercooling is necessary.

Contents of the invention

The technical problem to be solved by the present invention is to provide a two-stage supercharged engine with an interstage cooler aiming at the defects of the prior art.

To solve this technical problem, the present invention provides a two-stage supercharged engine with an interstage cooler, including a two-stage supercharged system using two turbochargers and a cooling system with an interstage cooler, The two-stage supercharging system includes an air filter, a low-pressure stage compressor, an interstage cooler, a high-pressure stage compressor and an intercooler connected with the engine intake manifold, and a high-pressure air compressor communicated with the engine exhaust manifold. stage turbine, low-pressure stage turbine, said high-pressure stage turbine is connected with a supercharger discharge valve in parallel, the supercharger discharge valve is controlled by a pulse valve, the pulse valve is connected with the engine ECU, and the engine ECU controls the opening work of the discharge valve Condition and opening ratio; the cooling system includes two parallel cooling circuits for cooling the pre-compressed intake air cooling circuit and the compressed intake air cooling circuit, and the two coolants are directly taken from the engine water tank for cooling.

The precompressed intake air cooling circuit includes an engine water tank, a water pump, an interstage cooler and a thermostat.

The compressed intake air cooling circuit includes an engine water tank, a water pump, an engine water outlet main pipe and a thermostat.

Beneficial effects: the present invention includes new components such as an inter-stage controllable air release valve and an inter-stage intercooling circuit. The two-stage supercharging system uses a small turbine to meet the responsiveness requirements, so that the engine can achieve maximum torque at a relatively low speed, and a large turbine can meet the responsiveness requirements. High torque requirements, by controlling the ratio of the exhaust gas to drive the two turbines, while meeting a large compression ratio and a large flow rate, it does not generate more pumping losses.

Description of drawings

Fig. 1 is a schematic diagram of the structure principle of the present invention.

In the figure: 1 air filter, 2 low-pressure compressor, 3 low-pressure turbine, 4 intercooler, 5 high-pressure compressor, 6 high-pressure turbine, 7 intercooler, 8 thermostat, 9 water pump, 10 engine water tank, 11 engine intake manifold, 12 engine, 13 engine outlet pipe, 14 engine exhaust manifold, 15 pulse valve, 16 supercharger air release valve, 17 engine ECU.

detailed description

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

Figure 1 shows a schematic diagram of the structure and principle of the present invention.

The present invention includes a two-stage supercharging system using two turbochargers and a cooling system with an interstage cooler 4, the two-stage supercharging system includes an air filter 1 communicated with the engine intake manifold, Low-pressure stage compressor 2, interstage cooler 4, high-pressure stage compressor 5 and intercooler 7, and high-pressure stage turbine 6 and low-pressure stage turbine 3 communicated with the exhaust manifold of the engine, and the high-pressure stage turbine 6 is connected in parallel Supercharger air release valve 16 is arranged, and this supercharger air release valve 16 is controlled by pulse valve 15, and pulse valve 15 is connected with engine ECU17, and engine ECU17 controls the opening working condition and opening ratio of supercharger air release valve 16; The above-mentioned cooling system includes two parallel cooling circuits for cooling pre-compressed intake air cooling circuit and compressed intake air cooling circuit, and both cooling liquids are directly taken from the engine water tank 10 for cooling.

The precompressed intake air cooling circuit includes an engine water tank 10 , a water pump 9 , an interstage cooler 4 and a thermostat 8 .

The compressed intake air cooling circuit includes an engine water tank 10 , a water pump 9 , an engine water outlet main pipe 13 and a thermostat 8 .

Work and principle and working process of the present invention:

(1) Fresh air enters the low-pressure stage compressor 2 through the air filter 1, and the compressed air reaches the engine intake manifold 11 after passing through the interstage cooler 4, the high-pressure stage compressor 5 and the intercooler 7, and then Distributed to each cylinder, after the fresh air is pressurized by the low-pressure stage compressor 2 and the high-pressure stage compressor 5, the intake air volume is more, which can make the combustion more complete;

(2) When the pressurized gas reaches the intake manifold 11, the pulse valve 15 will control the opening and closing of the supercharger purge valve 16 according to the air pressure in the engine intake manifold 11 and the electrical signal command sent by the engine ECU17 Level: When the engine 12 is at idle speed, low speed or low load, the engine ECU 17 sends the duty cycle of the pulse valve corresponding to the working condition to the pulse valve 15 according to the collected speed and torque signals, and the pulse valve 15 sends the duty cycle to the pulse valve 15. The signal is converted into an actual opening, and the opening of the pulse valve 15 determines the air pressure entering the supercharger air release valve 16, thereby affecting the opening of the air release valve;

When the pressure relief valve 16 of the supercharger is not required to vent, the high-pressure gas in the pipeline between the pressure relief valve 16 and the pulse valve 15 is discharged from the A end of the pulse valve 15, and the pulse valve 15 makes the supercharger discharge The gas valve 16 is closed, and exhaust gas is sent from the engine exhaust manifold 14 to the high-pressure stage volute 6 and the low-pressure stage volute 3 to perform work and drive the corresponding high-pressure stage compressor 5 and low-pressure stage compressor 2 to work; when the engine 12 is in the When running at a relatively high speed and with a relatively high load, the engine ECU 17 transmits a signal to the pulse valve 15, and the pulse valve 15 partially opens the supercharger bleed valve 16, and part of the exhaust gas passes from the high-pressure stage turbine 6 to the low-pressure stage turbine 3, and the other part of the exhaust gas directly flows from the The engine exhaust manifold 14 is directly sent to the low-pressure stage turbine 3 to reduce the speed and supercharging efficiency of the high-pressure stage turbine 6; when the intake pressure of the intercooler 7 is too high, the engine ECU 17 transmits a signal to the pulse valve 15, and the pulse valve 15 makes The supercharger exhaust valve 16 is fully opened, most of the exhaust gas enters the low-pressure stage turbine 3 through the exhaust channel, and only a small part of exhaust gas enters the high-pressure machine turbine 6;

(3) The pre-compressed intake air cooling circuit can provide low-temperature pre-compressed air for the high-pressure stage compressor 5: the water is taken from the engine water tank 10 by the water pump 9 and compressed into the interstage cooler 4 to cool the pre-compressed intake air, thus directly Taking water from the engine water tank 10 into the interstage cooler 4 greatly improves the cooling effect, which is conducive to improving the supercharging efficiency of the high-pressure stage and reducing fuel consumption. After cooling the coolant in the interstage cooler 4, it returns to the thermostat 8 through the pipeline. In, enter the engine cooling cycle;

(4) The compressed air intake cooling circuit uses the water pump 9 to directly take water from the engine water tank 10, and after compression, it reaches the cylinder block, cylinder head, etc. for cooling. After cooling, the coolant returns to the thermostat 8. When the coolant temperature is low , the thermostat 8 is closed, and the coolant returns to the water pump 9 through the engine water outlet main pipe 13 to carry out a small internal cycle of the engine; when the coolant temperature is high, the thermostat 8 is slowly opened, and part of the coolant returns to the engine water tank 10, At this time, the large and small cycles of the engine are carried out simultaneously; when the temperature of the coolant exceeds the temperature at which the thermostat 8 is fully opened, the thermostat 8 is fully opened, and all the coolant returns to the engine water tank 10, and the engine 12 performs a large cycle;

(5) Interstage controllable supercharger air release valve 16 is set in parallel with high-pressure stage turbine 6, and this supercharger air release valve 16 is connected in series with a pulse valve 15 controlled by engine ECU17. When the gas volume is too much, the outlet gas pressure of the pulse valve 15 controls the opening of the supercharger purge valve 16, and bypasses part of the waste gas that does not perform work to the low-pressure stage turbine 3;

The pulse valve 15 is controlled by the engine ECU17, but it not only controls the switch of the supercharger bleed valve 16, but also controls the opening range of the supercharger bleed valve 16 at almost any speed, so as to achieve stepless control in all working conditions, so that Effectively improve the fuel economy of the engine 12 at low load and idle speed and the emission performance at high speed; High-temperature gas entering the high-pressure stage compressor will result in a decrease in boosting efficiency. Therefore, the compressed high-temperature gas needs to be cooled before entering the high-pressure stage compressor, that is, inter-stage cooling is necessary.

The invention includes new components such as inter-stage controllable air release valve and inter-stage intercooling circuit. The two-stage supercharging system uses a small turbine to meet the responsiveness requirements, so that the engine can achieve maximum torque at a relatively low speed, and a large turbine can meet high torque requirements. , by controlling the proportion of the two turbines driven by the exhaust gas, it can satisfy a large compression ratio and a large flow rate without generating more pumping losses.

The above-mentioned embodiments of the present invention are just examples, not the only ones, and all changes within the scope of the present invention or equivalent to the scope of the present invention are embraced by the present invention.

Claims (3)

1. the two-stage pressurization engine of a band interstage cooler, it is characterized in that: comprise the two-stage supercharging system adopting two turbo-supercharger and the cooling system with interstage cooler (4), described two-stage supercharging system comprises the air filter (1) being connected with engine intake manifold, lower pressure stage pneumatic plant (2), interstage cooler (4), high pressure stage pneumatic plant (5) and charge air cooler (7), and the high pressure stage turbine (6) being connected with engine exhaust house steward, lower pressure stage turbine (3), described high pressure stage turbine (6) is parallel with supercharging blower purging valve (16), this supercharging blower purging valve (16) is controlled by pulse valve (15), pulse valve (15) is connected with Engine ECU (17), the unlatching operating mode of Engine ECU (17) control supercharging blower purging valve (16) and the ratio of unlatching, described cooling system comprises the parallel cooling loop that cooling precompression inlet gas cooling loop is independent of each other with compress inlet air cooling loop two, all directly water intaking cooling from engine water tank (10) of two-way cooling fluid.

2. the two-stage pressurization engine of band interstage cooler according to claim 1, it is characterised in that: described precompression inlet gas cooling loop comprises engine water tank (10), water pump (9), interstage cooler (4) and thermostat (8).

3. the two-stage pressurization engine of band interstage cooler according to claim 1 and 2, it is characterised in that: described compress inlet air cooling loop comprises engine water tank (10), water pump (9), engine outfall sewer (13) and thermostat (8).