JP2012026297A - Supercharging device with supercharging assist - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a supercharging device with a supercharging assist, capable of adjusting an amount of air introduced into a combustion chamber.SOLUTION: The supercharging device includes a turbocharger 806, a backflow prevention valve 807 that shuts an intake pipe 803 in an upstream side of a low-pressure turbocharger 806 during the supercharging assist, a pressure accumulation tank 808 accumulating compressed air for a supercharging assist, an accumulated pressure release valve 809 for emitting air from the pressure accumulation tank 808 during the supercharging assist, and an emission pipe 810 from the pressure accumulation tank 808. The emission pipe 810 is provided with an emission adjusting valve 101 that is driven by air pressure from an intake manifold 804 and reduces an opening of the valve when the inner pressure of the intake manifold 804 increases.

Description

  The present invention relates to a supercharging device with supercharging assistance that uses a pressure accumulating tank for supercharging assistance to alleviate turbo lag in a turbocharged engine, and is equipped with supercharging assistance that can adjust the amount of air introduced into a combustion chamber. Relates to the device.

  In an engine using a turbocharger (supercharger), more air can be sucked into the combustion chamber by the action of the turbocharger, so that it is possible to improve torque performance and reduce pollutants in the exhaust gas.

  A turbocharger has an impeller attached to each end of a single shaft. The turbocharger rotates the turbine by flowing exhaust through one impeller (turbine), and the other impeller (compressor) that rotates thereby causes air to flow. Compress. As described above, the turbocharger is a system that compresses air by work extracted from exhaust gas. Engines using a turbocharger increase the amount of air introduced into the combustion chamber by repeating the cycle of supercharging the air compressed by the turbocharger into the combustion chamber and further rotating the turbine with exhaust from the engine I will let you.

JP-A-8-260991

  Turbochargers have the problem of turbo lag. The turbo lag is a time difference from when the turbocharger is requested for the amount of air until the amount of air can be taken into the combustion chamber. Turbo lag is a phenomenon that always occurs on the principle of turbocharger. In particular, turbo lag is likely to occur during transient operation where the engine condition has changed.

  When the turbo lag occurs, the output torque performance and the exhaust performance deteriorate because the amount of air sucked into the combustion chamber is small with respect to the fuel amount determined from the changing engine speed and accelerator opening.

  As a supercharging assist device that improves the deterioration of output torque performance and exhaust performance due to turbo lag, air that has been compressed in advance using a supercharger or compressor for accumulating pressure is stored in the accumulator tank, and air from the accumulator tank is taken into the intake path during turbo lag There is something that supplements the amount of air by releasing it.

  A conventional supercharging device with supercharging assistance is shown in FIG.

  The supercharging device with supercharging assistance shown in FIG. 8 is connected to a turbine 802 that is rotated by exhaust gas from an engine 801 and a compressor 805 that compresses air obtained from the atmosphere through an intake pipe 803 and sends the compressed air to an intake manifold 804. A low pressure turbocharger 806, a backflow prevention valve 807 that shuts off the intake pipe 803 upstream of the low pressure turbocharger 806 at the time of supercharging assistance, a pressure accumulation tank 808 in which compressed air for supercharging assistance is stored, and supercharging assistance Sometimes, one end is connected to the pressure-accumulation release valve 809 for releasing air from the pressure-accumulation tank 808, the outlet of the pressure-accumulation release valve 809, and the other end is connected to the intake pipe 803 between the low-pressure turbocharger 806 and the backflow prevention valve 807. A discharge pipe 810.

  More specifically, an exhaust pipe 812 that guides exhaust gas from the exhaust manifold 811 to the atmosphere is switched between an exhaust passage through the turbine 814 of the high-pressure turbocharger 813 and a direct exhaust passage from the exhaust manifold 811 to the turbine 802. An exhaust gas switching valve 815 for flowing exhaust gas is provided. A waste gate valve 817 that diverts the exhaust gas to the exhaust switching valve 815 is provided in the high-pressure turbo exhaust pipe 816 that guides the exhaust gas from the exhaust manifold 811 to the turbine 814.

  An intake pipe 803 downstream of the compressor 805 of the low-pressure turbocharger 806 is connected to an inlet of the compressor 818 of the high-pressure turbocharger 813 and one inlet of an intake air switching valve 819 that switches the intake air flow path. A high-pressure turbo intake pipe 820 from the outlet of the compressor 818 is connected to the other inlet of the intake air switching valve 819. An intake pipe 803 downstream of the intake air switching valve 819 is connected to an intake manifold 804 via an intercooler 821. An intake throttle 822 is provided downstream of the intercooler 821. An air cleaner 823 is provided upstream of the backflow prevention valve 807 in the intake pipe 803. An air amount sensor 824 is provided immediately upstream of the inlet of the compressor 805.

  An oxidation catalyst (Diesel Oxidation Catalyst; DOC) 825 and a diesel particulate filter (Diesel Particulate Filter or Defuser; DPF or DPD) 826 are provided downstream of the outlet of the turbine 802 of the low-pressure turbocharger 806.

  A pressure accumulating compressor 827 for taking in compressed air is connected to the pressure accumulating tank 808.

  As shown in FIG. 9, in normal operation, that is, because the engine rotation speed and output torque do not change significantly and the accelerator opening is a steady operation, the turbo lag hardly occurs and supercharging assistance is not performed. At this time, the backflow prevention valve 807 is opened so that air from the atmosphere can be sucked into the compressor 805 of the low-pressure turbocharger 806. The pressure accumulation release valve 809 is closed. By such valve control, compressed air is not discharged to the discharge pipe 810, but only air from the atmosphere is introduced into the low-pressure turbocharger 806 and supercharged to the engine 801. At this time, the pressure accumulating compressor 827 is operated to store the compressed air in the pressure accumulating tank 808.

  As shown in FIG. 10, at the time of supercharging assistance, that is, when the engine rotation speed and the output torque change greatly, and in a transient operation where the accelerator opening greatly increases at a stretch, turbo lag is likely to occur, so supercharging assistance is performed. At this time, the backflow prevention valve 807 is closed so that the compressed air does not flow back to the air cleaner 823 upstream of the intake pipe 803, and the pressure accumulation release valve 809 is opened. By such valve control, the compressed air in the pressure accumulation tank 808 is supplied to the compressor 805.

  However, in the supercharging device with supercharging assistance, when there is a large amount of air stored in the accumulator tank 808 in advance, if this is released, the amount of air introduced into the combustion chamber of the engine 801 becomes larger than the necessary amount. For this reason, an overshoot occurs in which the engine rotation speed becomes larger than the target. That is, as shown in FIG. 11 (a), after the supercharging assistance that closes the backflow prevention valve 807 and opens the pressure accumulation release valve 809 is started, the amount of air introduced into the combustion chamber of the engine 801 is no supercharging assistance. Since the output torque increases faster than the case, the output torque rises quickly, but the air amount becomes excessive and the output torque greatly exceeds the target. At this time, as shown in FIG. 11B, an overshoot occurs in which the engine rotation speed becomes larger than the target.

  Further, depending on the engine state, the compressed air released from the pressure accumulating tank 808 is introduced into the combustion chamber, so that the pressure in the combustion chamber may become equal to or higher than the limit value defined for the engine 801. As shown in FIG. 11C, in the state where the air amount after the start of supercharging assistance has been exceeded, the maximum value of the combustion chamber pressure is much larger than that without supercharging assistance.

  In addition, the shortening of the ignition delay period accompanying the increase in the amount of air introduced into the combustion chamber adversely affects the exhaust gas performance.

  Accordingly, an object of the present invention is to solve the above-described problems and provide a supercharging device with supercharging assistance that can adjust the amount of air introduced into the combustion chamber.

  In order to achieve the above object, the present invention provides a turbocharger in which a turbine rotated by engine exhaust and a compressor that compresses air obtained from the atmosphere through an intake pipe and sends the compressed air to an intake manifold, and supercharging assistance A backflow prevention valve that sometimes shuts off the intake pipe upstream of the turbocharger, a pressure accumulation tank in which compressed air for supercharging assistance is stored, and a pressure accumulation release valve that releases air from the pressure accumulation tank during supercharging assistance A supercharging device with supercharging assistance comprising a discharge pipe having one end connected to the outlet of the pressure accumulation release valve and the other end connected to an intake pipe between the turbocharger and the backflow prevention valve; The discharge pipe is provided with a discharge control valve that is driven by the air pressure from the intake manifold and whose opening degree decreases when the internal pressure of the intake manifold increases. Those were.

  The release regulating valve is housed in the valve chamber movably in the valve chamber, which forms an air passage from the pressure accumulation release valve to the discharge pipe, and opens the air passage from fully open to fully closed. A valve body that is variably adjusted, a rod that is inserted from the outside of the valve chamber into the valve chamber and connected to the valve body, an actuator that drives the rod with air pressure, and the actuator to the intake manifold, Drive air piping that guides air from the intake manifold to the actuator may be provided.

  The present invention exhibits the following excellent effects.

  (1) The amount of air introduced into the combustion chamber can be adjusted.

It is a block diagram of the supercharging device with supercharging assistance which shows one Embodiment of this invention. It is a figure which shows the valve control at the normal time of the supercharging device with supercharging assistance of FIG. It is a figure which shows valve control at the time of supercharging assistance of the supercharging device with supercharging assistance of FIG. It is a figure which shows valve control at the time of supercharging assistance adjustment of the supercharging device with supercharging assistance of FIG. FIG. 2 is an internal detail view of a valve portion of the supercharging device with supercharging assistance in FIG. It is a figure which shows the internal motion in the valve control of the structure of FIG. 5, (a) is normal time, (b) is at the time of supercharging assistance, (c) is the time of the opening degree at the time of supercharging assistance adjustment, (d ) Indicates when the opening is small during supercharging assist adjustment. It is a figure which shows the characteristic of the supercharging apparatus with a supercharging assistance of this invention, (a) is a change waveform figure of the output torque when not performing supercharging assistance, (b) When performing supercharging assistance FIG. 6 is a waveform diagram showing a change in the maximum value of the combustion chamber pressure when not performed. It is a block diagram of the conventional supercharging device with supercharging assistance. It is a figure which shows the valve control at the normal time of the supercharging device with supercharging assistance of FIG. It is a figure which shows valve control at the time of supercharging assistance of the supercharging device with supercharging assistance of FIG. It is a figure which shows the characteristic of the conventional supercharging device with a supercharging assistance, (a) is a change waveform figure of the output torque when not performing supercharging assistance, (b), When performing supercharging assistance FIG. 5C is a waveform diagram of change in the maximum value of the combustion chamber pressure when the supercharging assistance is performed and when it is not performed.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  As shown in FIG. 1, the supercharging device with supercharging assistance according to the present invention compresses air obtained from an atmosphere through an intake pipe 803 and a turbine 802 rotated by exhaust of an engine 801 into an intake manifold 804. A turbocharger (hereinafter referred to as a low-pressure turbocharger) 806 connected to a compressor 805 to be sent, a backflow prevention valve 807 that shuts off the intake pipe 803 upstream of the low-pressure turbocharger 806 during supercharging assistance, and compressed air for supercharging assistance , An accumulator release valve 809 for releasing air from the accumulator tank 808 at the time of supercharging assistance, one end connected to the outlet of the accumulator release valve 809, a low pressure turbocharger 806 and a backflow prevention valve 807, A supercharging device with supercharging assistance, comprising a discharge pipe 810 having the other end connected to an intake pipe 803 between Te, the discharge pipe 810, the intake is driven by air pressure from the manifold 804, those having a modified release valve 101 internal pressure becomes higher when the opening is reduced in the intake manifold 804.

  As described above, the supercharging device with supercharging assistance of the present invention adds the release control valve 101 to the supercharging device with supercharging assistance of FIG. 8, and the release control valve 101 opens in accordance with the internal pressure of the intake manifold 804. It is intended to be adjusted. The relationship between the internal pressure of the intake manifold 804 and the opening degree of the release control valve 101 is set in advance by experiments.

  The operation of the supercharging device with supercharging assistance according to the present invention will be described below.

  As shown in FIG. 2, during normal operation, that is, when there is no supercharging assistance because of a steady operation in which turbo lag is unlikely to occur, the backflow prevention valve 807 is opened and air from the atmosphere is compressed by the compressor 805 of the low-pressure turbocharger 806. Make sure you can inhale. The pressure accumulation release valve 809 is closed. The discharge regulating valve 101 is open because the internal pressure of the intake manifold 804 is low. By such valve control, compressed air is not discharged to the discharge pipe 810, but only air from the atmosphere is introduced into the low-pressure turbocharger 806 and supercharged to the engine 801. At this time, the pressure accumulating compressor 827 is operated to store the compressed air in the pressure accumulating tank 808.

  As shown in FIG. 3, at the time of supercharging assistance (before supercharging assistance adjustment starts), that is, when the supercharging assistance is being performed because of the transient operation in which turbo lag is likely to occur, the backflow prevention valve 807 is closed and the intake air is inhaled. The compressed air is prevented from flowing back to the air cleaner 823 upstream of the pipe 803, and the pressure accumulation release valve 809 is opened. The discharge control valve 101 is fully opened because the internal pressure of the intake manifold 804 is low. By such valve control, the compressed air in the pressure accumulation tank 808 is supplied to the compressor 805.

  As shown in FIG. 4, the internal pressure of the intake manifold 804 is increased during the supercharging assist adjustment, that is, due to the effect of the supercharging assist, and the opening degree of the discharge control valve 101 is decreased. As a result, the amount of compressed air introduced into the compressor 805 of the low-pressure turbocharger 806 is reduced, and the amount of air introduced into the combustion chamber of the engine 801 does not exceed.

  Next, the detailed structure of the discharge regulating valve 101, the backflow prevention valve 807, and the pressure accumulation release valve 809 will be described with reference to FIG.

  The release control valve 101 is housed in the valve chamber 102, which forms an air passage from the pressure accumulation release valve 809 to the discharge pipe 810, and is movable in the valve chamber 102. The air passage is fully opened to fully closed. From the valve body 103 that is variably adjusted to the opening degree, the rod 104 that is inserted from the outside of the valve chamber 102 into the valve chamber 102 and connected to the valve body 103, the actuator 105 that drives the rod 104 with air pressure, and the actuator 105 A drive air pipe 106 is provided to the intake manifold 804 and guides the air in the intake manifold 804 to the actuator 105.

  The actuator 105 is a member that is hollow and elastic like a bellows pipe, for example, and is expanded or contracted in one direction according to the internal pressure. When high-pressure air is introduced from the driving air pipe 106 to the actuator 105, When the rod 104 is expanded to push the internal pressure of the intake manifold 804, air is discharged from the actuator 105 and the rod 104 is pulled back.

  The actuator 105 is fully opened when the internal pressure of the intake manifold 804 guided by the driving air pipe 106 is less than a predetermined value. When the internal pressure of the intake manifold 804 exceeds the predetermined value, the internal pressure of the intake manifold 804 increases. The expansion / contraction amount with respect to the internal pressure is set so that the opening degree is reduced accordingly.

  The backflow prevention valve 807 includes a valve chamber 807a inserted into the intake pipe 803 and a valve body 807b provided in the valve chamber 807a and driven by a solenoid (not shown).

  The pressure accumulation release valve 809 includes a valve chamber 809a connected to the discharge pipe 810 via the discharge control valve 101, and a valve body 809b provided in the valve chamber 809a and driven by a solenoid (not shown).

  As shown in FIG. 6A, in the normal state, in the backflow prevention valve 807, the valve body 807b opens the valve chamber 807a, and the air from the air cleaner 823 is introduced into the compressor 805. In the pressure accumulation release valve 809, the valve body 807b closes the valve chamber 809a, and the compressed air in the pressure accumulation tank 808 is not released. The discharge control valve 101 is fully open.

  As shown in FIG. 6B, during the supercharging assistance, in the backflow prevention valve 807, the valve body 807b closes the valve chamber 807a, and the compressed air is prevented from flowing back to the air cleaner 823. In the pressure accumulation release valve 809, the valve body 807b opens the valve chamber 809a, and the compressed air is released. At this time, the discharge control valve 101 is fully opened.

  As shown in FIG. 6C, when the internal pressure of the intake manifold 804 reaches a predetermined value, the opening degree of the release control valve 101 becomes slightly smaller than fully opened. Further, as shown in FIG. 6D, when the internal pressure of the intake manifold 804 greatly exceeds a predetermined value, the opening degree of the discharge control valve 101 is further reduced.

  As shown in FIG. 7A, in the supercharging device with supercharging assistance of the present invention, when supercharging assistance is performed, the amount of air introduced into the combustion chamber of the engine 801 is without supercharging assistance. Since the output torque rises faster than before, the output torque rises quickly, and when the internal pressure of the intake manifold 804 increases, the opening of the discharge control valve 101 is adjusted, so that the amount of air does not exceed. Therefore, the output torque is almost stabilized at the target value, and the overshoot of the engine rotation speed as shown in FIG. 11B is eliminated.

  As shown in FIG. 7 (b), in the supercharging device with supercharging assistance according to the present invention, the opening degree of the discharge control valve 101 is adjusted according to the internal pressure of the intake manifold 804, so that the maximum value of the combustion chamber pressure is increased. Is suppressed, and the pressure in the combustion chamber does not exceed the limit value defined for the engine 801.

  As described above, according to the supercharging device with supercharging assistance according to the present invention, the discharge pipe 810 is driven by the air pressure from the intake manifold 804, and the opening degree decreases when the internal pressure of the intake manifold 804 increases. Since the discharge adjustment valve 101 is provided, the turbo lag is eliminated by supercharging assistance, and when the internal pressure of the intake manifold 804 increases during supercharging assistance, the amount of air introduced into the combustion chamber is adjusted to be reduced. The engine rotational speed overshoot is eliminated and the combustion chamber pressure does not exceed the limit value.

  The air amount may be adjusted by, for example, providing an air pressure sensor in the intake manifold 804, attaching a solenoid valve to the discharge pipe 810, and electronically controlling the release of the solenoid valve, but a control delay occurs. In that respect, according to the supercharging device with supercharging assistance according to the present invention, there is no need to provide an air pressure sensor in the intake manifold 804, and the release regulating valve 101 is driven by the internal pressure of the intake manifold 804. There is no delay.

  In the present embodiment, the high-pressure turbocharger 813 is provided in addition to the low-pressure turbocharger 806. However, the present invention is effective even in a configuration having only the low-pressure turbocharger 806.

  In this embodiment, compressed air is discharged to the inlet of the compressor 805 of the low-pressure turbocharger 806 to assist supercharging. However, it may be discharged to the high-pressure side downstream from the outlet of the compressor 805. In this case, the turbo lag can be made even smaller. However, it is necessary to increase the compressed air pressure of the pressure accumulating tank 808 and to devise measures for preventing backflow.

101 Release Control Valve 801 Engine 804 Intake Manifold 806 Turbocharger 807 Backflow Prevention Valve 808 Accumulation Tank 809 Accumulation Release Valve 810 Discharge Piping

Claims (2)

A turbocharger in which a turbine rotated by the exhaust of the engine and a compressor that compresses air obtained from the atmosphere via the intake pipe and sends it to the intake manifold; and
A backflow prevention valve that shuts off the intake pipe upstream of the turbocharger during supercharging assistance, a pressure accumulating tank in which compressed air for supercharging assistance is stored,
An accumulator opening valve for releasing air from the accumulator tank during supercharging assistance;
In a supercharging device with supercharging assistance comprising a discharge pipe having one end connected to the outlet of the pressure accumulation release valve and the other end connected to an intake pipe between the turbocharger and the backflow prevention valve,
A supercharging device with supercharging assistance, characterized in that the discharge pipe is provided with a discharge control valve that is driven by air pressure from the intake manifold and whose opening degree decreases when the internal pressure of the intake manifold increases. The release regulating valve is
A valve chamber that forms an air passage from the pressure-accumulation release valve to the discharge pipe;
A valve body that is accommodated in the valve chamber movably in the valve chamber, and adjusts the opening of the air passage from fully open to fully closed;
A rod inserted from outside the valve chamber into the valve chamber and connected to the valve body;
An actuator for pneumatically driving the rod;
The supercharging device with supercharging assistance according to claim 1, further comprising a drive air pipe that is laid from the actuator to the intake manifold and guides the air of the intake manifold to the actuator.

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