DE102013100065A1 - Combustion engine system i.e. diesel engine system, for use in vehicle, has valve phase shift device performing backward or forward operation of high pressure exhaust valve or low pressure exhaust valve relative to crankshaft - Google Patents

Abstract

The system (100) has a high pressure exhaust valve control device (121) coupled with a high pressure exhaust valve (120). A low pressure exhaust valve (122) is arranged between a combustion cylinder and a low pressure exhaust gas manifold (118). A low pressure exhaust valve control device (123) is coupled with the low pressure exhaust valve. A valve phase shift device is coupled with the high pressure and low pressure exhaust valve control devices and performs backward or forward operation of the high pressure exhaust valve or the low pressure exhaust valve relative to a crankshaft (105). An independent claim is also included for a method for controlling an exhaust gas flow of a combustion engine system.

Description

CROSS REFERENCE TO RELATED PATENT APPLICATION

The present patent application claims the benefit of US Provisional Patent Application No. 61 / 584,016, filed Jan. 6, 2012, the teachings and disclosures of which are hereby incorporated by reference in their entirety by reference.

FIELD OF THE INVENTION

This invention relates generally to combustion system exhaust systems, and more particularly to combustion system exhaust systems which utilize exhaust gas recirculation and one or more turbochargers to increase engine output and reduce exhaust emissions.

GENERAL PRIOR ART

Internal combustion engines use a combustion cycle to combust fuel and oxygen to convert the energy of the fuels into mechanical energy for powering devices such as automobiles, locomotives, generators, and many other devices.

Many modern engines (spark-ignition and self-ignition) use the exhaust gases emitted by the engine for various useful activities. A special activity is the use of the exhaust gases for the drive of a turbocharger. The flow of exhaust gases drives a turbine of the turbocharger, which in turn drives a compressor to increase the amount of air supplied to the engine. The increased amount of air supplied to the engine allows a higher power density, which improves fuel economy and transient response.

Exhaust gases are also used to reduce emissions. One problem with internal combustion engines, and especially diesel engines, is that NOx is generated at high combustion temperatures. Further, the generation of NOx is typically nonlinear, so that an incremental increase in temperature may significantly increase the NOx production rate.

Another problem with internal combustion engines, and particularly diesel engines, is that when the combustion cycle is relatively rich in fuel, i. H. close to the stoichiometric ratio for complete combustion (but still with an excess of oxygen), the engine produces a large amount of soot. The soot may interfere with the operation of the engine and downstream components of the exhaust system and provide undesirable emissions.

In view of ever-increasing energy / fuel costs and increasingly stringent emissions regulations, it is desirable to increase fuel economy while reducing the amount of emissions produced.

In order to reduce NOx emissions, exhaust gas is recirculated, known as "exhaust gas recirculation" (the term "EGR gas" is used hereafter to refer to the exhaust gas itself being recirculated) to the temperatures in the cylinder during reduce the combustion. The primary constituents of EGR gas are carbon dioxide ("CO ₂ ") and water vapor, plus nitrogen and residual oxygen, which was not consumed by the fuel in a previous cycle. In general, the exhaust gas is substantially inert. Carbon dioxide and water vapor have high specific heat to air. In this respect, a larger amount of energy is needed to increase the temperature of these components. Therefore, the temperatures in the cylinder during combustion are lower when these gases are present than when they are absent. EGR gas can be used to reduce temperatures in the cylinder

To improve the ability of the EGR to control or limit the temperature in the cylinder, the EGR gas is usually passed through an EGR cooler which dissipates heat energy from the EGR gas before the EGR gas is mixed with the intake gas , This reduces the temperature of the EGR gas and thereby allows the EGR gas to consume more energy during combustion to more effectively control and maintain the temperature in the cylinder.

A schematic representation of a conventional four-stroke internal combustion engine 10 shows 1 , As shown, the engine points 10 a single exhaust manifold 12 on that with all the exhaust valves 14 of the motor 10 is coupled. The only exhaust manifold 12 collects all the exhaust gases from the engine 10 be generated. A turbo flow path 15 connects the exhaust manifold 12 with the turbine 16 of the turbocharger 18 , An EGR flow path 20 connects the exhaust manifold 12 functional with the intake flow path 22 to mix the EGR gas with the intake gases.

A problem with this current arrangement is that all the engine exhaust gas is fed into a single exhaust manifold which is connected to both the EGR flowpath and the turbine inlet flowpath. The problem is that each of these flowpaths makes specific demands for optimal conditions: (a) For the EGR flowpath, low temperature exhaust gases and at a pressure just sufficient to overcome intake manifold pressure and just sufficient EGR are desirable To direct flow from the exhaust manifold to the intake manifold while (b) a high temperature, high pressure, and high mass flow rate are desirable for the turbine to improve turbocharger performance and turbocharging pressure in the intake manifold. At present, the two functions are combined by using the common exhaust manifold, resulting in a compromise. The EGR loop is too hot and requires a high pressure to drive the EGR gas while the turbine circuit is too cool and the pressure is too low as the EGR loop has consumed some of the available pressure. The need for independence becomes clear when one considers that the turbine circuit generates the boost pressure which the EGR cycle must overcome and that the additional temperature in the EGR cycle must be eliminated via a heat exchanger. In view of this, it is clear that it is very unlikely that a single exhaust valve control using a common manifold will well meet both the requirements of the EGR and the requirements of the turbine.

Embodiments of the present invention provide improvements over the current state of the art to improve the distribution of exhaust gases to the turbine as well as for use as EGR gases to improve fuel economy while reducing emissions. These and other advantages of the invention as well as additional inventive features will be apparent from the description given herein.

BRIEF SUMMARY OF THE INVENTION

New and improved internal combustion engine systems and methods for controlling exhaust flow of internal combustion engine systems are provided. More specifically, new and improved combustion engine systems and methods of controlling exhaust flow using a split flow of ana are provided. The new and improved systems and methods are adapted to separate the exhaust gas based on its thermodynamic state. Therefore, the thermodynamically most suitable exhaust gas can be used to drive the turbine of a turbocharger, and the thermodynamically most suitable exhaust gas is used as the EGR gas, inter alia, to reduce NOx emissions. Increasing the amount of air in diesel engines, achievable due to increased turbine performance, allows for leaner operation and potentially reduced soot production.

In a specific embodiment, an internal combustion engine system is provided that includes an engine block, a gas intake system, an exhaust system, a crankshaft, and a valve phaser device. The engine block defines a cylinder. The gas intake system includes an intake manifold, at least one intake valve disposed between the cylinder and the intake manifold, and an intake valve control device operably coupled to the at least one intake valve to control the opening and closing of the intake valve. The exhaust system includes a high pressure exhaust manifold, at least one high pressure exhaust valve disposed between the cylinder and the high pressure exhaust manifold, and a high pressure exhaust valve control device operably coupled to the at least one high pressure exhaust valve to open and close the at least one high pressure exhaust valve control, up. The exhaust system further includes a low pressure exhaust manifold, at least one low pressure exhaust valve disposed between the cylinder and the low pressure exhaust manifold, and a low pressure exhaust valve control device operably coupled to the at least one low pressure exhaust valve to open and close the at least one low pressure exhaust valve to control. The valve phase displacement device is operably coupled to the inlet valve control device and the low pressure outlet valve control device and is configured to control the actuation of the at least one of At the same time, the intake valve and the at least one low pressure exhaust valve are retarded or advanced relative to the crankshaft.

By coupling the valve phase displacement device with both the intake valve control device and at least the low pressure exhaust valve control device, a simpler and less expensive control system can be provided without significantly affecting engine efficiency or NOx and soot reduction.

In a more specific embodiment, the intake valve control device and the low pressure exhaust valve control device are cam lobes on a camshaft, and the valve phase shifter is a single cam phaser. In a more specific embodiment, the intake valve control device, the high pressure exhaust valve control device, and the low pressure exhaust valve control device are separate cam lobes on a single camshaft, and the single valve phase shifter is a single camshaft phase shifter.

In one embodiment, the single valve phase displacement device is also operably coupled to the inlet valve control device, the high pressure outlet valve control device, and the low pressure outlet valve control device, and the single valve phase displacement device is configured to control actuation of the at least one inlet valve, the at least one high pressure outlet valve, and of the at least one low-pressure exhaust valve relative to the crankshaft zurückverstellen or vorzuverstellen simultaneously.

In a more specific embodiment, the intake valve control device is a cam lobe on a first camshaft; the high pressure outlet valve control device is at least a first cam lobe on a second camshaft configured to control the actuation of the at least one high pressure outlet valve; and the low pressure outlet valve control device is at least one second cam lobe on the second camshaft configured to control the actuation of the at least one low pressure outlet valve. The at least one second cam lobe on the second camshaft is configured differently than the at least one first cam lobe on the second camshaft.

In one embodiment, the engine block defines a plurality of combustion cylinders. The at least one high-pressure outlet valve is a plurality of high-pressure outlet valves, with each combustion cylinder having at least one high-pressure outlet valve. The at least one low-pressure outlet valve is a plurality of low-pressure outlet valves, each combustion cylinder having at least one low-pressure outlet valve. The at least one first cam lobe on the second camshaft is a plurality of first cam lobes associated with the plurality of high pressure exhaust valves, and the at least one second cam lobe on the second camshaft is a plurality of second cam lobes.

In another embodiment, an internal combustion engine system is provided that includes an internal combustion engine, an intake system, an exhaust system, a turbocharger, and an exhaust gas recirculation system. The internal combustion engine defines a combustion cylinder. The intake system supplies the engine with intake gases. The exhaust system removes exhaust gases from the engine. The exhaust system includes a high pressure exhaust manifold; a high pressure exhaust valve disposed between the combustion cylinder and the high pressure exhaust manifold; a low pressure exhaust manifold; and a low pressure exhaust valve disposed between the combustion cylinder and the low pressure exhaust manifold. The turbocharger has a turbine in the exhaust system in fluid communication with the high pressure exhaust manifold. The exhaust gas recirculation (EGR) system fluidly couples the low pressure exhaust manifold to the air intake system. The EGR system does not include an exhaust gas recirculation (EGR) valve disposed between the low pressure exhaust manifold and the air intake system.

In this embodiment eliminates the EGR valve, which is an expensive component that often requires warranty repairs, is removed from the engine system. The EGR valve may be eliminated because the flow of EGR gas from the exhaust system to the intake system is primarily controlled by the low pressure exhaust valves.

In a more specific embodiment, the EGR system includes an exhaust gas recirculation cooler (EGR cooler).

In another embodiment, a valve control system is provided. The valve control system is configured to control the opening and closing of the high pressure outlet valve and to control the opening and closing of the low pressure outlet valve. The valve control system is configured to vary the opening and closing angles of the high pressure outlet valve and configured to vary the opening and closing angles of the low pressure outlet valve. As a result, the subsets of the exhaust gas are set, which are admitted into the high-pressure or in the low-pressure exhaust manifold.

In another embodiment, the valve control system is configured to adjust the opening and closing of the high pressure exhaust valve independently of the opening and closing of the low pressure exhaust valve. In this respect, the control of the high-pressure and the low-pressure outlet valve is completely independent and without a mechanical connection.

In one embodiment, the valve control system is configured to retract or advance the opening and closing of the high pressure exhaust valve and is configured to retract or advance the opening and closing of the low pressure exhaust valve.

In one embodiment, an inlet valve is provided. The valve control system is configured to control the opening and closing of the intake valve.

In a more specific embodiment, the valve control system is configured to retard or advance the opening and closing of the intake valve and to retard or advance the opening and closing of the low pressure exhaust valve such that the timing of the intake valve and the low pressure exhaust valve must be advanced or retracted together.

In an even more specific embodiment, the valve control system is configured to retard or advance the opening and closing of the high pressure exhaust valve independently of any retard or advance of the opening and closing of the intake valve.

In one embodiment, a switching system is provided within the EGR system. The switching system is configured to fluidly connect the low pressure exhaust manifold to the air induction system in a first state and fluidly connect the low pressure exhaust manifold to an exhaust outlet downstream of the turbine in a second state. The switching system is incapable of incrementally adjusting the flow rate from the low pressure exhaust manifold to the air induction system through the switching system. In this embodiment, the switching system does not have an EGR valve.

In one embodiment, the EGR system includes a switching system. The switching system is configured to fluidly connect the low pressure exhaust manifold to the air induction system in a first state and fluidly connect the low pressure exhaust manifold to the exhaust system upstream of the turbine in a second state. The transfer system is unable to incrementally adjust its flow rate.

In a more specific embodiment, the switching system is further configured to fluidly connect the low pressure exhaust manifold to the exhaust system downstream of the turbine in a third state.

In one embodiment, the fluidic coupling between the low pressure exhaust manifold and the air intake system is free of valves.

In one embodiment, a low pressure outlet valve control device is operably coupled to the at least one low pressure outlet valve to control the opening and closing of the low pressure outlet valve. The low-pressure outlet valve control device is configured to open the low-pressure outlet valve control device at or after a bottom dead center of a piston within the combustion cylinder of a four-cycle engine.

In another more specific embodiment, a method of controlling exhaust flow from an internal combustion engine system is provided. The engine system includes an intake system; a high pressure exhaust system having a high pressure outlet valve operable with a turbine of a Turbocharger is in fluid communication; and a low pressure exhaust system including a low pressure exhaust valve operatively connected to the intake system by an exhaust gas recirculation (EGR) system. The method includes driving the turbine with a first exhaust stream flowing through the high pressure exhaust system and having a first thermodynamic characteristic having a first value; and returning a second exhaust stream to the intake system via the EGR system from the low pressure exhaust system, the second exhaust stream having a second value of the first thermodynamic characteristic, the second value being different from the first value.

In a more specific method, the first thermodynamic characteristic is entropy and the first value is greater than the second value. In another method, the first value is at least 50 J / (kg · K) greater than the second value.

In another embodiment, a method of controlling exhaust flow from an internal combustion engine system is provided. The engine system includes an intake system; a high pressure exhaust system including a high pressure exhaust valve ("HP exhaust valve") operably fluidly connected to a turbine of a turbocharger and a low pressure exhaust system including a low pressure exhaust valve operable by an exhaust gas recirculation (EGR) system the suction system is in fluid communication. The method includes driving the turbine of the turbocharger with a first subset of exhaust gas expelled from the internal combustion engine via the HP exhaust valve; returning a second subset of exhaust gas expelled from the internal combustion engine via the LP exhaust valve to the intake system via the EGR system; receiving an intake gas pressure setpoint representing a desired intake gas pressure; and phasing (shifting the timing, phase shifting) the HP exhaust valve based on the intake gas pressure setpoint to provide flow of the first portion of exhaust gas at a sufficient flow rate to drive the turbine with sufficient energy to provide the desired intake gas pressure ,

In a more specific embodiment, the method includes measuring an intake gas pressure actual value; comparing the intake gas pressure actual value with the intake gas pressure target value; and adjusting the phasing of the HP exhaust valve if the intake gas pressure actual value is out of a predetermined range of the intake gas pressure setpoint.

In one embodiment, the step of adjusting the phasing of the HP exhaust valve includes advancing the phasing of the HP exhaust valve if the intake gas pressure actual value is less than the predetermined range. In addition, the step of adjusting the phasing of the high-pressure exhaust valve may include retarding the phasing of the high-pressure exhaust valve if the intake gas pressure actual value is larger than the predetermined range.

In an embodiment, the method further comprises measuring the pressure and the temperature of the first subset of exhaust gas. In addition, the phasing of the HP exhaust valve includes determining a phase using the intake gas pressure setpoint, the measured pressure, the measured temperature, and a theoretical model of intake gas pressure control. The method also includes measuring an intake gas pressure actual value; comparing the intake gas pressure setpoint with the intake gas pressure actual value; and modifying the theoretical model of control of intake gas pressure based on deviations between the intake gas pressure setpoint and the intake gas pressure actual value. This method allows for adaptive feedforward control.

In a more specific embodiment, the pressure and temperature of the first subset of exhaust gas are sensed within an HP exhaust manifold disposed between the HP exhaust valve and the turbine of the turbocharger.

In another embodiment, the step of modifying the theoretical model of intake gas pressure control comprises adjusting constants within the theoretical model of intake gas pressure control.

In one embodiment, the step of phasing the HP exhaust valve includes determining a predicted phasing of the HP exhaust valve using a theoretical model of intake gas pressure control.

In an embodiment, the method further comprises: measuring the pressure and the temperature of the first subset of exhaust gas; and wherein determining the phasing of the HP exhaust valve is using of the suction gas pressure target value, the measured pressure and the measured temperature of the first subset of exhaust gas, and the theoretical model of the control of the intake gas pressure.

In one embodiment, the method further comprises: measuring an intake gas pressure actual value; Comparing the intake gas pressure setpoint with the intake gas pressure actual value; and modifying the theoretical model of control of intake gas pressure based on deviations between the intake gas pressure setpoint and the intake gas pressure actual value.

In another embodiment, a method of controlling exhaust flow from an internal combustion engine system is provided. The engine system includes an intake system; a high pressure exhaust system including a high pressure exhaust valve ("HP exhaust valve") operably fluidly connected to a turbine of a turbocharger and a low pressure exhaust system including a low pressure exhaust valve operable by an exhaust gas recirculation (EGR) system the suction system is in fluid communication. The method includes driving the turbine of the turbocharger with a first subset of exhaust gas expelled from the internal combustion engine via the HP exhaust valve; returning a second subset of exhaust gas expelled from the internal combustion engine via the LP exhaust valve to the intake system via the EGR system; receiving a setpoint of the EGR flow rate; and phasing the LP exhaust valve to provide a flow rate of the second subset of exhaust gas at a sufficient flow rate and thermodynamic state to supply the intake system with EGR gas at the EGR flow rate set point.

In a more specific embodiment, the method comprises measuring a temperature actual value of the second subset of exhaust gas; comparing the actual temperature value with a temperature setpoint value; and adjusting the phasing of the HP and / or LP exhaust valves if the actual temperature value is not within a predetermined range of the temperature setpoint.

In an even more specific embodiment, the step of adjusting the phasing of the HP and / or LP exhaust valves includes retarding the phasing of the HP exhaust valve and either advancing or retarding the LP exhaust valve if the actual EGR temperature is greater than that given range is.

In another embodiment, the step of adjusting the phasing of the HP and / or LP exhaust valves includes advancing the phasing of the HP exhaust valve and either advancing or retarding the LP exhaust valve if the actual EGR temperature is less than the predetermined range is.

In an embodiment, the method includes measuring an actual EGR flow rate of the second subset of exhaust gas; comparing the actual value of the EGR flow rate with the target value of the EGR flow rate; and adjusting the phasing of the HP and / or LP exhaust valves if the actual EGR flow rate is not within a predetermined range of the EGR flow rate setpoint.

In one embodiment, the step of adjusting the phasing of the HP and / or LP exhaust valves comprises re-adjusting the phasing of the HP exhaust valve and either advancing or retarding the LP exhaust valve if the actual EGR flow rate is greater than the predetermined one Area is.

In another embodiment, the step of adjusting the phasing of the HP and / or LP exhaust valves includes advancing the phasing of the HP exhaust valve and either advancing or retarding the LP exhaust valve if the actual EGR flow rate is less than that given range is.

In another embodiment, the method includes measuring a pressure actual value and a temperature actual value of the second subset of exhaust gas, and phasing the HP and / or LP exhaust valves comprises determining a phase using the setpoint EGR flow rate, pressure actual value, Temperature actual value and a theoretical model of the control of the EGR flow. The method further comprises measuring an actual value of the EGR flow rate; comparing the setpoint value of the EGR flow rate with the actual value of the EGR flow rate; and modifying the theoretical model of EGR flow control based on deviations between the EGR flow rate setpoint and the EGR flowrate actual value.

In a further embodiment, the method comprises comparing the actual temperature value with a temperature setpoint value; and adjusting the phasing of the HP and / or LP exhaust valves if the actual temperature value is not within a predetermined range of the temperature setpoint.

In another embodiment, the step of adjusting the phasing of the HP and / or LP exhaust valves includes retarding the phasing of the HP exhaust valve and either advancing or retarding the LP exhaust valve if the actual EGR temperature is greater than the predetermined range is.

In another embodiment, the method includes comparing the actual temperature value to a temperature setpoint value; and modifying the theoretical model of EGR flow control if the actual temperature value is not within a predetermined range of the temperature setpoint.

In other embodiments, the NOx generation may be monitored, and the valve timing of both the high pressure and low pressure exhaust valves may be adjusted when the NOx levels are above a predetermined threshold. In some cases, the step of adjusting the phasing of the HP and / or LP exhaust valves includes advancing the phasing of the HP exhaust valve and either advancing or retarding the phasing of the LP exhaust valve if a measured level of NOx is greater than that is predetermined threshold. This then causes a greater amount of exhaust gases to be used as the EGR gas, which should additionally contribute to reducing NOx emissions.

Further, the measured NOx levels may be used to adjust any theoretical models pertaining to EGR control and, in particular, a theoretical model of EGR flow control.

In a more specific method, the method further comprises: measuring a measured NOx value in the exhaust gas; and comparing the measured NOx value with a predetermined NOx threshold value; and adjusting the phasing of the HP exhaust valve if the measured NOx value is above the predetermined NOx threshold.

In another, more specific method, the step of adjusting the phasing of the HP exhaust valve includes re-adjusting the phasing of the HP exhaust valve.

In a more specific method, the method further comprises modifying a theoretical model of EGR flow control based on deviations between the measured NOx value and the predetermined NOx threshold.

In one embodiment, the method further comprises adjusting the phasing of the LP exhaust valve if the measured NOx value is above the predetermined NOx threshold.

In one embodiment, the steps of adjusting the phasing of the HP and LP exhaust valves include advancing or retarding the HP exhaust valve while advancing the phasing of the LP exhaust valve.

In an embodiment, the method further comprises: measuring a measured NOx value in the exhaust gas; and comparing the measured NOx value with a predetermined NOx threshold value; and adjusting the phasing of the LP exhaust valve if the measured NOx value is above the predetermined NOx threshold.

In another embodiment, an internal combustion engine system is provided that ensures fully independent variable valve timing. The internal combustion engine includes an engine block, a gas intake system, an exhaust system, a crankshaft and at least one valve phaser device. The engine block defines a combustion cylinder. The gas intake system includes an intake manifold, at least one intake valve disposed between the cylinder and the intake manifold, and an intake valve. A control device operably coupled to the at least one intake valve to control the opening and closing of the intake valve. The exhaust system includes a high pressure exhaust manifold, at least one high pressure exhaust valve disposed between the cylinder and the high pressure exhaust manifold, and a high pressure exhaust valve control device operably coupled to the at least one high pressure exhaust valve to open and close the at least one high pressure exhaust valve control, up. The exhaust system further includes a low pressure exhaust manifold, at least one low pressure exhaust valve disposed between the cylinder and the low pressure exhaust manifold, and a low pressure exhaust valve control device operably coupled to the at least one low pressure exhaust valve to open and close the at least one low pressure exhaust valve to control. The at least one valve-phase shifting device is operably coupled to the intake valve control device, the high-pressure exhaust valve control device, and the low-pressure exhaust valve control device, and is configured to independently actuate the at least one intake valve, the at least one high-pressure exhaust valve, and the at least one low-pressure exhaust valve relative to the crankshaft retract or advance.

The at least one valve-phase shifting device may be one or more devices. For example, in a more specific embodiment, the intake valve control device has a first camshaft, the high pressure exhaust valve control device has a second camshaft, and the low pressure exhaust valve control device has a third camshaft. The at least one valve-phase shifting device comprises a plurality of devices, each of which controls only the timing of one of the camshafts. More specifically, the at least one valve-phase shifter includes first, second, and third camshaft phasers. The first camshaft phaser is operably coupled only to the first camshaft to retard or advance actuation of only the at least one intake valve independently of the at least one high pressure exhaust valve and the at least one low pressure exhaust valve. The second camshaft phaser is operably coupled to only the second camshaft to retard or advance the actuation of only the at least one high pressure exhaust valve independently of the at least one low pressure exhaust valve and the at least one inlet valve. The third camshaft phaser is operably coupled only to the third camshaft to retard or advance the actuation of only the at least one low pressure exhaust valve independently of the at least one high pressure outlet valve and the at least one inlet valve.

In an alternative embodiment, the inventive aspects may be applied to an internal combustion engine having no adjustable intake valves, such as a two-stroke diesel engine. The internal combustion engine system includes an engine block defining a combustion cylinder, a gas intake system having an intake manifold, an exhaust system, a crankshaft, and at least one valve-phase shifting device. The exhaust system includes a high pressure exhaust manifold, at least one high pressure exhaust valve disposed between the cylinder and the high pressure exhaust manifold, and a high pressure exhaust valve control device operably coupled to the at least one high pressure exhaust valve to open and close the at least one high pressure exhaust valve control, up. The exhaust system further includes a low pressure exhaust manifold, at least one low pressure exhaust valve disposed between the cylinder and the low pressure exhaust manifold, and a low pressure exhaust valve control device operably coupled to the at least one low pressure exhaust valve to open and close the at least one low pressure exhaust valve to control. The at least one valve phase displacement device is operably coupled to the high pressure outlet valve control device and the low pressure outlet valve control device and is configured to independently retard or advance the actuation of the at least one high pressure outlet valve and the at least one low pressure outlet valve relative to the crankshaft.

The at least one valve-phase shifting device may be one or more devices. For example, in one embodiment, the high pressure exhaust valve control device has a first camshaft, and the low pressure exhaust valve control device has a second camshaft. The at least one valve-phase shifting device has first and second camshaft phase shifters. The first cam phaser is operably coupled only to the first camshaft to retard or advance the actuation of only the at least one high pressure exhaust valve, independently of the at least one low pressure exhaust valve. The second camshaft phaser is operably coupled to only the second camshaft to retard or advance actuation of only the at least one low pressure exhaust valve, independently of the at least one high pressure exhaust valve.

In an alternative embodiment, the valve timings of the high pressure exhaust valve (the high pressure exhaust valves) and the low pressure exhaust valve (the low pressure exhaust valves) may be coupled, such as in a two stroke diesel engine. The internal combustion engine system includes an engine block defining a combustion cylinder, a gas intake system having an intake manifold, an exhaust system, a crankshaft, and a single valve phase displacement device. The exhaust system includes a high pressure exhaust manifold, at least one high pressure exhaust valve disposed between the cylinder and the high pressure exhaust manifold, and a high pressure exhaust valve control device operably coupled to the at least one high pressure exhaust valve to open and close the at least one high pressure exhaust valve control, up. The exhaust system further includes a low pressure exhaust manifold, at least one low pressure exhaust valve disposed between the cylinder and the low pressure exhaust manifold, and a low pressure exhaust valve control device operably coupled to the at least one low pressure exhaust valve to open and close the at least one low pressure exhaust valve to control. The single valve phase displacement device is operably coupled to the high pressure outlet valve control device and the low pressure outlet valve control device and configured to simultaneously retard or advance the actuation of the at least one high pressure exhaust valve and the at least one low pressure exhaust valve relative to the crankshaft.

In one embodiment, the high pressure outlet valve control device and the low pressure outlet valve control device are provided by different cam lobes of a single camshaft. The single valve phase shifter is operably coupled to the single camshaft.

Other aspects, objects, and advantages of the invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and form a part of the specification, illustrate several aspects of the present invention and, together with the description, serve to explain the principles of the invention. In the drawings show:

1 a schematic representation of a motor system according to the prior art;

2 a schematic representation of an embodiment of an engine system according to the present invention, having a split-flow exhaust system;

3 an entropy-temperature diagram for comparing the thermodynamic properties of the exhaust gases flowing into the turbine and used as EGR gases for a conventional engine system and an engine system according to 2 ;

4 a schematic turbine control circuit for controlling HD exhaust valves for driving the turbine of embodiments of engine systems according to the present invention;

5 a schematic EGR control circuit for controlling ND exhaust valves for supplying EGR gas to the intake system of embodiments of engine systems according to the present invention;

6 an embodiment of a valve timing system for adjusting the valve timing of the intake, HP exhaust and LP exhaust valves of the engine system, wherein the phasing of the valve timing of the HP exhaust valves is independent of the phasing of the valve timing of the LP exhaust valves and the intake valves;

7 an embodiment of a valve control system for adjusting the valve timing of the intake, HP exhaust and LP exhaust valves of the engine system, wherein the phasing of all valves is the same;

8th a schematic representation of an alternative embodiment of an engine system according to the present invention having a split flow exhaust system having a Umschaltventilanordnung;

9 a schematic representation of an embodiment of an engine system according to the present invention having a split-flow exhaust system, the engine system is a Uniflow (two-stroke) DC engine system;

10 a simplified representation of the internal combustion engine of the engine system of 9 ;

11 a diagram showing the crankshaft angle for various operations of the internal combustion engine of the engine system of 9 illustrated;

12 a plot of enthalpy availability to compare the thermodynamic properties of exhaust gases entering the turbine and used as EGR gases for a conventional engine system and engine system, respectively 2 ; and

13 an embodiment of a valve control system for adjusting the valve timing of the intake, HP exhaust and LP exhaust valves of the engine system, wherein the phasing of all valves is independent.

Although the invention will be described in connection with certain preferred embodiments, it is not intended to be limited to these embodiments. Rather, it is intended to cover all alternatives, modifications, and equivalents, which are included in the spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE INVENTION

2 is a schematic representation of an embodiment of an engine system 100 according to the teachings of the present invention. The engine system 100 is designed to improve fuel economy and reduce emissions by using a split flow exhaust system to control the use of exhaust gases. This type of system may also be referred to herein as a "split current design." The engine system 100 controls the use of the exhaust gases to maximize the thermodynamic properties of the exhaust gases for various operations, including driving a turbocharger and ensuring exhaust gas recirculation (EGR), inter alia, to reduce NOx emissions and soot production. As mentioned above, the term "EGR gas" will be used hereafter to refer to the exhaust gas itself, which is to the fresh air intake side of the engine system 100 is returned.

First, the engine system 100 and various subsystems and components of the engine system 100 explained.

As is known, the engine system includes 100 essentially an internal combustion engine 102 , which is adapted to burn suction gases with fuel to generate mechanical energy. The combustion takes place inside combustion cylinders 103 ("Cylinder 103 ") Of an engine block 101 of the internal combustion engine 102 instead of. The combustion of the mixture of fuel and intake gas drives pistons (not shown) which are connected to a crankshaft 105 are operatively coupled to produce a rotary motion by means of the burned gases. The movement of the crankshaft 105 can then be used to drive a device such as a vehicle, a generator, another machine, etc. The engine block 101 , the pistons and a cylinder head (not shown) define combustion chambers where the intake gases mixed with the fuel are compressed and then burned.

The engine system 100 includes an intake system 104 for supplying suction gases to the cylinders 103 so that they are mixed with fuel to convert to mechanical energy. The intake system 104 typically has an inlet 106 which is exposed to a source of intake gases, typically the ambient air, which is the engine system 100 surrounds. The inlet 106 stands with an intake manifold 108 via a network of pipes between the inlet and the intake manifold 108 operable in fluid communication.

Several inlet valves 110 are operable between the intake manifold 108 and the cylinders 103 arranged to supply the intake gases to the cylinders 103 to control selectively. The intake valves 110 can take various forms and could be, for example, cam actuated or solenoid actuated valves. Furthermore, although every cylinder 103 shown with two inlet valves For example, other embodiments have more or fewer intake valves that correspond to a given cylinder 103 assigned.

An intake valve control device 109 ( "EV-control device 109 ") Is with the inlet valves 110 Operationally coupled and interacts with them to open and close the intake valves 110 to control. In the simplest case, the intake valve control device could 109 take the form of a cam lobe camshaft, with the crankshaft 105 operatively coupled, such as by a timing belt, a timing chain or possibly via gears. In alternative embodiments, the EV control device 109 a valve phasing device for adjusting the timing of opening and closing the intake valves 110 such as a camshaft phase shifter (cam phaser). Furthermore, the intake valve control device could 109 have electronic control elements or part of an electronic control unit 134 of the engine system 100 be or be coupled with such to control the opening and closing of the valves and to adjust the timing of the same. Furthermore, the intake valve control device could 109 electromagnetic or other valve actuators other than cam actuators, as are well known in the art.

In the illustrated embodiment is a suction cooler 111 between the turbocharger compressor 128 and the intake manifold to supply the intake gases prior to delivery to the cylinders 103 to cool. The suction cooler 111 is typically an air-to-air heat exchanger; however, other cooling devices could be implemented.

The engine system 100 also has an exhaust system 112 essentially designed for exhaust gases from the internal combustion engine 102 dissipate. The exhaust system 112 has an outlet 114 on which the exhaust gases ultimately from the engine system 100 be ejected. Typically, the exhaust gases are expelled back into the ambient air, which is the internal combustion engine 102 surrounds.

The exhaust system 112 is essentially a split-flow exhaust system, which is a high-pressure exhaust manifold 116 ( "HD exhaust manifold 116 ") And a low-pressure exhaust manifold 118 ( "ND-exhaust manifold 118 "), Which collect separate subsets of the exhaust gases when the exhaust gases from the cylinders 103 flow out. Several high pressure outlet valves 120 ( "HD exhaust valves 120 ) are fluid between the HP exhaust manifold 116 and the cylinders 103 arranged to selectively flow out a first subset of the exhaust gases from the cylinders 103 in the HD exhaust manifold 116 to enable. Similarly, there are several low pressure exhaust valves 122 ( "ND-exhaust valves 122 ") Fluidly between the LP exhaust manifold 118 and the cylinders 103 arranged to selectively flow out a second subset of the exhaust gases from the cylinders 103 in the LP exhaust manifold 118 to enable.

The HD and LP exhaust valves 120 . 122 can take various forms and could be, for example, cam actuated or solenoid actuated valves. Furthermore, although every cylinder 103 shown with an HP exhaust valve and a ND exhaust valve, other embodiments more HD exhaust valves or more LP exhaust valves 120 . 122 have a given cylinder 103 assigned. Furthermore, a single cylinder needs 103 not the same number of HP exhaust valves 120 like ND exhaust valves 122 exhibit. The HD and LP exhaust valves 120 . 122 may be different in shape, size, stroke, etc.

A high pressure outlet valve control device 121 ( "HDAV control device 121 ") Is with the high pressure outlet valves 120 Operationally coupled and interacts with them to open and close the high pressure outlet valves 120 to control. A low pressure outlet valve control device 123 ( "NDAV control device 123 ") Is with the low pressure outlet valves 122 Operationally coupled and interacts with them to open and close the low-pressure outlet valves 122 to control. The HDAV control device 121 and the NDAV control device 123 could take the form of separate cam lobed camshafts with the crankshaft 105 operatively coupled, such as by a timing belt or a timing chain. In alternative embodiments, the HDAV control device 121 and the NDAV control device 123 Valve phase shift mechanisms such as camshaft phase shifters for adjusting the timing for opening and closing the HP exhaust valves 120 or the LP exhaust valves 122 exhibit. Furthermore, the HDAV control device could 121 and the NDAV control device 123 have electronic control elements or part of the electronic control unit 134 of the engine system 100 be or coupled with this to control the opening and closing of the valves and to adjust the timing of the same. Furthermore, the HDAV control device could 121 and the NDAV control device 123 electromagnetic or other valve actuators that are not cam actuators, as are well known in the art, for adjusting valve timing. If camshafts as part of the HDAV control device 121 and the NDAV control device 123 are used, the camshafts are typically separated from each other, such as using fully independent variable valve timing. However, if equal variable valve timing is used, the HDAV controller and the NDAV controller could be separate sets of cam lobes on a single camshaft. A group of cam lobes would be for operating the HP exhaust valves 120 trained, and the other group of cam lobes would be for operating the LP exhaust valves 122 educated.

If the same variable valve timings are used for the exhaust valves as well as for the intake valves, the same cam walls could have three different groups of cam lobes, with a group of cam lobes as the EV control device 109 is configured to actuate the intake valves, the second group of cam lobes as the HDAV control device 121 for controlling the HP exhaust valves 120 is formed and the third group of cam lobes as the NDAV control device 123 for controlling the LP exhaust valves 122 is trained. Alternatively, various of the camshafts that control the intake valves, the HP exhaust valves and the ND exhaust valves could be mechanically coupled, such as by timing chains or gears, to adjust the timing of the same.

In embodiments of the present invention, other valve phase displacement devices may also be used as the camshaft phase shifter. For example, the eccentric sleeve valve phasing devices disclosed in U.S. Patent Nos. 5,316,355 and 5,355,347 could be used U.S. Patent No. 6,155,216 by Riley, entitled "Variable Valve Apparatus" (hereinafter "the '216 patent), the teachings and disclosure of which are incorporated herein by reference in their entirety, for adjusting valve timing. For example, if the system uses fully independent valve timing, the EV control device may 109 a camshaft and a camshaft phase shifter, as explained above. The HDAV control device 121 and the NDAV control device 123 could then be provided by a mechanism utilizing the eccentric sleeve valve phase displacement devices of the '216 patent.

Other valve phase displacement devices may be used. For example, a device that adjusts the position of a rocker arm to adjust the valve timing, as described in US Patent Application Publication No. US 2010/0083922 by Riley, entitled "Varying the Phase and Lift of a Rocker Arm to a Camshaft Actuating a Valve or Injector" (hereinafter "the '922 patent), the teachings and disclosures of which are incorporated herein by reference in their entirety are involved.

Valve-phase displacement devices may also be electro-hydraulic or electro-mechanical valve-phase displacement devices.

As such, embodiments of the invention may employ alternative mechanisms for adjusting valve timing.

The engine system 100 contains a turbocharger 124 which is a turbine 126 which is operable within the exhaust system 112 is positioned and in fluid communication with the exhaust gases, leaving exhaust gases from the internal combustion engine 102 by at least and typically only by the HP exhaust manifold 116 emanate, the turbine 126 drive. The turbine 126 is fluid between the HP exhaust manifold 116 and the exhaust outlet 114 arranged, and in particular upstream of the exhaust outlet 114 and downstream of the HP exhaust manifold 116 ,

The turbocharger may use a fixed geometry turbine, such as a free flow turbocharger or a wastegate turbocharger, but preferably employs a variable geometry turbine ("VTG turbine") with the opening in the turbine is variable, among other things to restrict exhaust gases and to allow control of the back pressure. In addition, the turbocharger could use a variable nozzle turbine.

In the illustrated embodiment, the turbine is 126 operable with a compressor 128 of the turbocharger 124 coupled, which is operable within the intake system 104 is positioned to assist the increase in mass and pressure of the intake gases that the internal combustion engine 102 be supplied. The compressor 128 is preferably upstream of the suction cooler 111 arranged, so that the intake gases supplied heat energy by means of the suction cooler 111 can be dissipated. In alternative embodiments, the turbine could 126 operatively coupled to a turbocompound drive so that the turbine shaft is operable with the crankshaft of the engine 102 can be coupled. The term "turbocharger" is used herein as a generic term to include at least those configurations in which a turbine drives a compressor or is a turbocompound drive.

The engine system 100 has an exhaust gas recirculation system 130 ( "EGR system 130 ) for supplying EGR gas to the intake system 104 on. The EGR system 130 couples the LP exhaust manifold 118 fluidic with the intake system 104 , leaving exhaust gases in the LP exhaust manifold 118 ensure the supply of EGR gas. Furthermore, the EGR gas may be used to reduce the cylinder temperature and thereby the NOx generation of the engine system 100 to reduce.

The EGR system 130 has an EGR cooler 132 through which the EGR gas is passed and cooled, before the EGR gas enters the intake system 104 is supplied. The EGR cooler 132 can take various forms, such as those of air-liquid or air-to-air heat exchangers.

Some embodiments of the engine system 100 have an electronic control unit 134 (electronic control unit, "ECU 134 "), Which with the components of the engine system 100 is operably coupled to control and monitor the functions of the various components and the system as a whole. The ECU 134 can with the various sensors to monitor the engine system 100 be operably coupled; These sensors may include throttle position, crankshaft position, cam sensors, coolant temperature, HP and LP exhaust duct temperatures, HP and LP exhaust pressure and temperature, NOx reading before any NOx aftertreatment system, position of variable valve train (VVT) if not off cam position, cylinder pressure, EGR flow rate, EGR pressure and temperature, engine speed, and others. Furthermore, the ECU 134 operable with the intake valve control device 109 , the HDAV control device 121 and the NDAV control device 123 be connected to the timing of opening and closing the intake valves 110 , the HD exhaust valves 120 or the LP exhaust valves 122 to control, ie zurückverstellen and / or vorzuverstellen.

An advantage of the shared flow exhaust system is that, if properly tuned and designed, there is no need to integrate an EGR valve into the EGR system. Thus, no active valve is needed for incrementally throttling the amount of EGR gas that is recycled, unlike earlier systems such as those in US Pat 1 shown. Instead, the LP exhaust valves 122 and the HDAV control device 123 be configured to control the amount of EGR gas, which to the intake system 104 is returned, and the engine system 100 does not have any EGR valve disposed between the low-pressure exhaust manifold and the intake system. By eliminating the EGR valve, a component frequently requiring warranty repairs may be removed from the system and EGR controlled by the exhaust valves.

By having a shared-flow exhaust system like the one in 2 is used, which uses separate, independent exhaust manifold, with separate, independent groups of exhaust valves 120 . 122 coupled, the control of which exhaust gas is used for which purpose can be optimized so that the thermodynamically most suitable exhaust gas is used to the turbine 126 of the turbocharger 124 while the thermodynamically most suitable exhaust gas is used as the EGR gas.

The split flow exhaust system separates the exhaust gas according to its potential to optimize the flow work in the turbine while returning a desired mass flow range of EGR gas to the intake manifold. It was determined that the initial exhaust gases coming out of the cylinders 103 of the internal combustion engine 102 outflow, have a high initial pressure peak and typically have a higher temperature and therefore have a higher working potential. As such, when the split flow type exhaust system described above is used, the initial high pressure ("high pressure") exhaust gases may be delivered to the turbine 126 of the turbocharger 124 be directed. This HD exhaust is from the cylinders 103 through the HD exhaust valves 120 ejected and to the turbine 126 the turbocharger passed to the for the drive of the turbocharger 124 optimize available energy and thereby increase the charging potential for the system.

Subsequently, subsequently ejected low pressure exhaust gases ("LP exhaust gases"), which tend to be cooler and lower in pressure, may be discharged from the cylinders 103 through the LP exhaust valves 122 expelled and through the EGR system 130 to the intake system 104 directed and used as EGR gas. Since the LP exhaust gases tend to have a lower temperature, the LP exhaust gases are more suitable for EGR. An immediate advantage is that less heat energy has to be removed from the EGR gas. In this respect can a smaller EGR cooler 132 be provided with a smaller rated cooling capacity, which reduces the cost.

The use of such a shared flow exhaust system can provide increased fuel economy and improved air-fuel ratio without the risk of increasing NOx production. This is especially true when there is a measurable difference between the thermodynamic properties of the HD exhaust gases and the LP exhaust gases. One such measurable difference is that there is a mean entropy difference of at least 50 J / (kg · K) between the EGR and turbine exhaust gas flow for engine operation above about 20% full load. In this mode of operation, the system has significant advantages in terms of fuel economy and emissions of internal combustion engines and, in particular, diesel internal combustion engines.

3 shows a Ts (temperature versus entropy) graph, which is used to determine the working potential of a gas state. Gas states in the upper right area (high temperature and high entropy) have the highest potential to do work. Gas states in the lower left area (low temperature - low entropy) have the lowest working potential. The Ts diagram compares a conventional engine system as in 1 shown with an engine system such as the engine system discussed above 100 , This diagram shows a turbocharged diesel engine operating at high load. The results are a schematic of an engine simulation model aimed at producing the same NOx emissions as a conventional engine, but with improved fuel economy and higher air-fuel ratio to achieve lower soot emissions.

As in 3 shown, have the exhaust gases 150 at the inlet of the turbocharger of the conventional engine, on average, a higher temperature, but, most importantly, a substantially lower entropy than the exhaust gases 152 at the inlet of the turbine 126 of the turbocharger 124 (ie the HD exhaust) in the split current design. The temperature differences are partly due to the additional air in the split current design. By pumping additional air and approximately the same amount of EGR gas, the split-flow design generally produces slightly lower exhaust gas effluent temperatures than the conventional engine under the same speed and load conditions. In addition, the EGR gases point 154 of the conventional engine, on average, has a higher temperature and a higher entropy than the EGR exhaust gases 156 (ie the LP exhaust gases) in the split current design.

Therefore, if the opening time of the HP exhaust valves is properly set, then 120 by the HDAV control device 121 the gas with high working potential according to the turbocharger charging requirements 124 sent while the properly phased ND exhaust valves 122 generated by the NDAV control device 123 controlled, lower entropy and lower temperature gas than EGR gas to the EGR cooler 132 and on to the intake manifold 108 send.

12 shows a graphical representation of the availability as a function of the enthalpy of the exhaust gas streams for the same operating state as in 3 has been used. "Availability" in this case is essentially the ability of the exhaust streams to do work, such as when the gas stream is passed through a turbine of a turbocharger. The graph illustrates that for the conventional engine, the availability and enthalpy of the EGR gas flow 410 and the inlet stream 412 of the turbocharger are very similar. In contrast, the split current design separates the enthalpies of the EGR gas flow 414 and the inlet stream 416 turbocharger, wherein higher enthalpy gases are supplied to the turbocharger with generally greater availability.

Methods in accordance with embodiments of the present invention include a control strategy for controlling exhaust gas flow based on EGR flow rate and intake gas pressure setpoint values provided by the main ECU 134 be sent. These setpoints are determined based on engine operating parameters including, but not limited to, speed, load, transient response requirements, NOx, soot generation, ambient pressure, and temperature.

The intake gas pressure setpoint indicates the required intake gas pressure. The intake gas pressure demand is used to determine the turbine power required to meet the intake gas pressure requirement, such that the turbocharger 124 can ensure the appropriate charge. It should be noted that charge is typically the pressure change from atmospheric pressure, while intake gas pressure is typically absolute pressure. However, the terms "charge" and "suction pressure" as used herein are essentially synonymous. The turbine power required to meet the intake gas pressure requirement results in the flow rate and gas state (eg, thermodynamic state) of the HP exhaust gases. This information is provided by the HDAV control device 121 the high pressure exhaust valve timing ("HP valve timing") to provide the turbine input power (based on a thermodynamic calculation) to meet the intake gas pressure requirement.

4 is a schematic turbine control loop 160 ( "TRK 160 ") For implementing an intake gas pressure control strategy to determine the HP valve timing based on a desired intake gas pressure. First, a suction gas pressure set point 162 from the ECU 134 accessed. This setpoint is typically determined by a master loop that uses, among other things, engine load and engine speed to determine the desired intake gas pressure. The TRK 160 then measures and analyzes the actual intake gas pressure 164 , If the intake gas pressure actual value is not equal to the intake gas pressure set value 162 is not within a predetermined range around the setpoint, the HP valve timing for the HD exhaust valves 120 adjusted. If the actual intake gas pressure is less than the intake gas pressure setpoint, the HP valve timing is advanced to deliver higher pressure, higher temperature gas to the turbine 126 to increase the input power and thus increase the turbine / compressor speed and consequently the turbocharger's supercharging and consequently the intake gas pressure. Similarly, if the actual intake gas pressure is above the intake gas pressure setpoint, the HP valve timings will be retarded to reflect the thermodynamic performance of the turbine 126 to reduce supplied exhaust gas and thus reduce the turbine / compressor speed and thus the charge and consequently the intake gas pressure.

In 4 a more detailed embodiment is shown. The TRK 160 is a model-based control. Model-based control includes adaptive feed forward and turbine power models, including a model of intake gas pressure control that controls the HP valve timing to drive turbocharger turbine 124 to control. In this embodiment, the pressure 167 and the temperature 169 HD exhaust gas in the HP exhaust manifold 116 monitors and uses the turbine power based on these parameters 168 to determine. This information is used in combination with the intake gas pressure setpoint to ensure the appropriate phasing of the HP exhaust valves 120 to determine. This information provides feed-forward control for adjusting the HP valve timing by calculating the turbine thermodynamic output and a calculated boost based on the thermodynamic properties of the HP exhaust.

In some embodiments, the model of suction gas pressure control is adaptive. In these adaptive models, the actual intake gas pressure, typically measured in the intake manifold, is compared to the intake gas pressure setpoint. The differences between the actual and set values may be used to adjust constants within the intake manifold pressure control model to maintain model accuracy for feedforward control. Specifically, if the deviation between actual charge and calculated charge exceeds a predetermined value, the deviation may be used to modify the model and maintain its accuracy. It should be noted that the model of the control of the suction gas pressure, including the model constants, in the ECU 134 or in a separate component with the ECU 134 operably coupled, can be stored.

It will open 5 Reference is made; the low pressure exhaust valve timing ("ND valve timing") is determined to provide the amount of EGR gas needed to supply the intake system 104 to dine. In this case, the best exhaust gas for the EGR, unlike the turbine, is the one with the lowest enthalpy, which is obtained after the lowest point of the piston stroke, ie at bottom dead center ("UT"), where the combustion gases within the combustion chamber of the internal combustion engine 102 have experienced the full expansion cooling. In this respect, the LP exhaust valves 122 preferably open at or after UT, and the amount of EGR flow is controlled by how long the LP exhaust valves 122 be left open and exhaust into the EGR system 130 emit. However, the timing for the LP exhaust may be advanced so that the LP exhaust valves 122 may be opened earlier (ie, at an earlier crankshaft angle) to provide a higher pressure in the cylinder for propelling the EGR gas through the LP exhaust manifold 118 and the EGR system 130 to receive. Alternatively, the timing for the LP exhaust may be retarded, closer to the end of the exhaust stroke, where the pressure in the cylinder increases due to compression by the piston movement toward top dead center. A proper phasing of LP exhaust valves 122 allows for minimizing the total pumping work (between blowdown and exhaust stroke) required to recycle the EGR gas through the EGR system 130 to drive.

The EGR flow rate requirements, along with the low pressure exhaust gas temperature, are monitored and the valve opening and closing times are determined to ensure the lowest average temperature of the EGR gas, while at the same time meeting the requirement for total mass flow for a correct NOx reduction is met. An additional advantage of using fully expanded exhaust gas for the EGR is that with the lower enthalpy undesirable pumping losses are reduced when the EGR gas is exhausted through the EGR system 130 is moved through.

5 is a schematic EGR control loop 170 ( "AGRRK 160 ") For implementing an EGR control strategy for determining LP valve timing based on a desired EGR flow rate. Again, the function of the AGRRK exists 170 This is to set the LP valve timings to produce sufficient pressure at the lowest temperature to reach the EGR flow rate setpoint. The AGRRK calls the setpoint of the EGR flow rate 172 from the ECU 134 from. The setpoint of the EGR flow rate 172 is determined by a higher level main loop using, among other things, engine speed and engine load.

In the simplest embodiment, the ND valve timings are adjusted to the setpoint of the EGR flow rate 172 to realize. As essentially stated above, advancing the ND valve timing during the power stroke creates more pressure to increase the EGR flow through the EGR system 130 but at the cost of higher EGR enthalpy. Timing the transition between opening the LP exhaust valve and closing the HP exhaust valve then controls the amount of EGR gas supplied to the intake manifold. The LP exhaust valve on a four-stroke engine almost always opens on the upstroke. In such a situation, the transfer of the EGR gas is performed by using the upward exhaust stroke of the piston. In that respect, problems associated with a required pressure drop between the EGR system 130 and the intake system 104 tempered by the fact that the EGR gas through the piston to the intake system 104 can be driven. Further, unlike prior art systems, there is no other flow path for the EGR gas, ie no flow path through the turbine 126 because at this point, during the piston cycle, this path is substantially sealed off from the EGR path.

Unlike the prior art designs, where the single exhaust manifold was connected to both the EGR system and the turbine of the turbocharger, in the split-flow design, the engine system can 100 be configured so that the only flow path for the LP exhaust gas passes through the EGR system. As such, there is no need for a sufficient pressure differential to drive the LP exhaust as EGR gas through the EGR system because the pistons can drive the EGR gas through the EGR system.

In a more advanced embodiment of the AGRRK, model-based control is used to perform calculations within the AGRRK 170 to model the engine EGR flow and pump power and to optimize valve timing and potentially the variable geometry turbine (VTG) blade positions.

More precisely, the AGRRK 170 For example, a model of EGR flow control utilizing a theoretical fluid flow model for EGR flow through a flow orifice (eg, minimum area or maximum restriction in the flow path of the EGR system 130 ) can be. The model may use the EGR temperature, the LP exhaust manifold pressure, the intake manifold pressure, as well as a flow restriction area and a flow coefficient or outflow coefficient. The model may also include an exhaust pulse multiplier. When the model is calibrated, the flow coefficient or effluent coefficient and exhaust pulse multiplier are adjusted to best model the EGR flow rate over a wide range of engine speed and engine load operating conditions. Alternatively, the system may be calibrated by using a mass flow meter (eg, an EGR flow rate sensor) in the EGR system 130 such as a virtual sensor, an algorithm that analyzes a pressure drop over a known flow orifice, a hot wire or a membrane deflection device to determine if a correct EGR flow rate is warranted is used. This detection then takes place within the EGR system 130 instead of before the EGR gas enters the intake system.

The EGR flow control model uses the LP exhaust temperature and the LP exhaust pressure in addition to the EGR flow rate set point 172 to determine the LP exhaust valve timing.

The AGRRK 170 may be adaptive, in which case the EGR flow control model uses the deviation between the actual EGR flow rate and the EGR flow rate set point to adjust the constants of the EGR flow control model. More precisely, the AGRRK 170 can measure the actual EGR flow rate and compare it to the EGR flow rate setpoint. If this error is outside a predetermined range, the constants of the EGR flow control model may be updated to maintain the accuracy of the on-board model of EGR flow control. The EGR flow rate sensor used for the calibration may also be used for the on-site real-time calibration of the EGR flow rate control model constants.

In addition to analyzing only the EGR flow rate, the actual temperature of the EGR gas may also be analyzed and used to adjust the LP valve timing. For example, the EGR setpoint may include an EGR temperature setpoint. Methods for controlling the flow of exhaust gas may include comparing the actual temperature of the exhaust gas with a temperature setpoint. The deviation between the actual value and the target value may be used to both adjust the ND valve timing and to modify the EGR flow rate control model if the error is outside predefined ranges.

NOx production may also be monitored and used to adjust the phasing of the HP exhaust valves and the LP exhaust valves. More specifically, actual values of the NOx level can be measured within the exhaust gas flowing out of the engine. The measured NOx levels may be compared to NOx level thresholds to determine if the EGR system is supplying sufficient EGR gas at the correct flow rate and thermodynamic state to lower the NOx level below the acceptable level Reduce NOx level.

If the measured NOx levels are too high, the phasing of the HP and LP exhaust valves may be adjusted to adjust the subset or condition of the exhaust gas used as the EGR gas. Typically, if the measured NOx levels are too high, the timing of the HP exhaust valve may be retarded to try to obtain exhaust that has undergone greater expansion and done more work on the piston of the engine, so that there is a lower temperature and more suitable for use as EGR gas. Alternatively, both the HP and LP exhaust valves may be advanced to allow more exhaust gas to be fed into the EGR loop, or the HP exhaust valve may be phased in one direction or the other while the LPD Exhaust valve is advanced, which may increase their overlap, thereby allowing a larger amount of EGR.

The measured NOx levels may also be used to adjust and modify any theoretical models of EGR flow control. For example, if measured NOx levels are greater than desired for a given set of operating parameters of the engine, the EGR flow control models may be adjusted to increase EGR or improve the quality of exhaust gas used as EGR gas.

Additionally, the HP valve timing and LP valve timing may be concurrently controlled using model-based multi-parameter control to achieve both intake gas pressure setpoints and EGR flow rate setpoints with a combination of the HP valve timing and LP valve timing adjustments.

The engine system 100 is designed for the HD exhaust valves 120 Within a range of 120 ° crankshaft to 160 ° crankshaft after top dead center (n. OT) to open, without enabling turbocharging. Enabling turbocharging can be done by opening the HP exhaust valves 120 to advance an additional 5 ° crankshaft to 10 ° crankshaft with respect to this timing range. By advancing even further, the transient response can be improved. The opening duration of the HP exhaust valve is typically about 65-75% of that of conventional engines. The Opening period of the LP exhaust valve is typically about 40-50% of that of conventional engines. Furthermore, the overlap between the opening of the LP exhaust valves 122 and closing the HP exhaust valves 120 between 30 ° crankshaft and 65 ° crankshaft.

The intake valves 110 are open in a range from 60 ° crankshaft to 10 ° crankshaft before top dead center (v. However, the opening time is up to about 10% longer than with conventional engines.

Applicants have determined through modeling that significant improvements in engine performance can be achieved using these operating methods.

On the basis of the described general operating environment and control theory, more specific features, alternative embodiments, and operating methods will now be described.

6 and 7 show valve control systems using less than fully independent variable valve timing for all of the engine system. Instead, at least two sets of valves, if not all, are phase shifted (ie, advanced or retarded) by an equal amount using these valve timing systems. Although the following embodiments will be described generally using camshaft phase shifters, the following examples are also applicable to the other types of valve phase shift devices discussed above. Further, the various embodiments could also use a combination of the different types of valve-phase shifting devices.

6 is a simplified schematic representation of an embodiment of a valve control system 174 , The valve control system 174 is functionally designed to operate, that is, to open and close the intake valves 110 , the HD exhaust valves 120 and the LP exhaust valves 122 if applicable, advance or retract.

The valve control system 174 In this embodiment, there is a pair of camshaft phasers 176 . 178 which are used to adjust valve timing. The ECU 134 can be considered part of the valve control system 174 and then performs the steps outlined above, and operatively operable with the camshaft phasers 176 . 178 communicate or control their operation to adjust valve timing.

The first camshaft phase shifter 176 is between the crankshaft 105 and the EV control device 109 which in this embodiment comprises a camshaft operably coupled. The first camshaft phase shifter 176 is also between the crankshaft 105 and the NDAV control device 123 which in this embodiment comprises a camshaft operably coupled. The first camshaft phase shifter 176 is adapted to the crankshaft angle of opening and closing for the intake valves 110 and the LP exhaust valves 122 to selectively advance or retract the same amount. In this respect, if the first camshaft phase shifter 176 For example, the timing adjusted by 4 ° crankshaft, both the intake valve timing and the ND valve timing by 4 ° crankshaft vorverstellt. In this respect, the intake valve timing and the ND valve timing are mechanically coupled. However, the valve timings for the HP exhaust valves become 120 not as a result of adjustments made using the first camshaft phase shifter 176 be implemented, adjusted.

The second camshaft phase shifter 178 is between the crankshaft 105 and the HDAV control device 121 which in this embodiment comprises a camshaft operably coupled. The second camshaft phase shifter 178 is designed to control the crankshaft angle of opening and closing the HP exhaust valves 120 to selectively advance or retract. This adjustment of the HP exhaust valve timing is completely mechanical, regardless of any adjustment of valve timing for the intake valves 110 or the LP exhaust valves 122 ,

Although the camshaft phase shifter 176 . 178 are shown schematically as gears / sprockets, the between gears / sprockets of the EV control device 109 , the HDAV control device 121 and the NDAV control device 123 are arranged, could the camshaft phase shifter 176 . 178 also be operably attached to individual camshafts. For example, the gear / sprocket included as part of the HDAV control device 121 is shown completely by the second camshaft phase shifter 178 be replaced. Similarly, the gear / Sprocket as part of the EV control device 109 or the NDAV control device 123 is represented by the first camshaft phase shifter 176 be replaced.

Further, although the camshaft phase shifter 176 is shown operatively engaged with two separate gears / sprockets, the EV control device 109 and the NDAV control device 123 be provided by a single camshaft, wherein the EV control device 109 is a first group of cam lobes on the camshaft and the NDAV control device 123 could be a second group of cam lobes on the same camshaft. Alternatively, other valve phase shifting devices could be used, such as those discussed above.

7 is a simplified schematic representation of another embodiment of a valve control system 182 , Like the previous valve control system 174 is the valve control system 182 functionally adapted to the operation, that is the opening and closing, of the intake valves 110 , the HD exhaust valves 120 and the LP exhaust valves 122 to advance or retract. The valve control system 182 however, is more simplified than the valve control system 174 ,

The valve control system 182 has a single camshaft phase shifter in this embodiment 184 which is used to adjust valve timing. Also in this case, the ECU 134 as part of the valve control system 182 can be viewed and then performs the steps outlined above, and it can functionally with the camshaft phase shifter 184 communicate or control its operation.

The camshaft phase shifter 184 is as on the crankshaft 105 shown attached, and he is with the EV control device 109 , the NDAV control device 123 and the HDAV control device 121 operably coupled. Although he considered being direct with each of the three valve control devices 109 . 121 . 123 shown coupled, could be the camshaft phase shifter 184 also with one of the three valve control devices 109 . 121 . 123 be directly coupled, and then the three valve control devices 109 . 121 . 123 operatively connected to each other instead of directly with the camshaft phase shifter 184 to be coupled.

In this embodiment, the only camshaft phase shifter 184 adapted to the operation, ie the crankshaft angle of the opening and closing, the intake valves 110 , the HD exhaust valves 120 and the LP exhaust valves 122 by the same amount relative to the crankshaft 105 to selectively advance or retract. This valve control system 182 can therefore be referred to as a control system with the same control of all variable valve timing ("all-equal VVT control system").

In this valve control system 182 when the camshaft phase shifter 184 For example, the timing advance by 4 ° crankshaft, the intake valve timing, the HP valve timing and the ND valve timing each advanced by 4 ° crankshaft. In this respect, the intake valve timing, the HP valve timing and the ND valve timing are mechanically coupled, so that an adjustment of the timing of one of these valve groups has an adjustment at all result.

Further, although the camshaft phase shifter 184 is shown operatively engaged with three separate gears / sprockets, the EV control device 109 , the HDAV control device 121 and the NDAV control device 123 be provided by a single camshaft, wherein the EV control device 109 a first group of cam lobes on the camshaft is the HDAV control device 121 is a second group of cam lobes on the camshaft and the NDAV control device 123 is a third group of cam lobes on this camshaft. The camshaft phase shifter could then be mounted or mounted directly on the end of this camshaft. Alternatively, other valve phase shifting devices could be used, such as those discussed above.

These two valve control systems 174 . 182 are simpler than using fully independent valve timing for each of the three different groups of valves 110 . 120 . 122 , Therefore, any reduction in the camshaft phase shifter provides an advantage in terms of simplifying the design and reducing the maintenance effort as well as the risk of damage.

It should be noted that it is quite possible for embodiments of the invention to have completely independent valve timing for each of the three groups of valves 110 . 120 . 122 use. 13 shows such an embodiment of a fully independent valve control system 179 , which has three camshaft phase shifters 185 - 187 having. Each camshaft phase shifter independently controls the valve timing of a single group of valves. For example, the camshaft phase shifter 185 the valve timing of the intake valves 110 control, the camshaft phase shifter 186 can control the valve timing of the HP exhaust valves 120 control, and the camshaft phase shifter 187 can control the valve timing of the ND exhaust valves 122 Taxes. Again, other types of valve-phasing devices could be used to ensure fully independent valve timing. Further, a mixture of valve-phase shifters could be implemented to separate individual ones from the intake valves, HP and LP exhaust valves 110 . 120 . 122 to control.

Other embodiments of the invention may include fixed valve timing for the intake valves 110 use while phasing the HD exhaust valves 120 and LP exhaust valves 122 enable. (This could be the case, for example, with the Uniflow (DC) two-stroke diesel engines discussed below, where the intake timing is fixed.) The phasing of the HP exhaust valves 120 and LP exhaust valves 122 could be coupled or independent of each other. For example, a single valve phase shifter could be used to simultaneously control both the HP and LP exhaust valves 120 . 122 (ie, a single camshaft phase shifter coupled to a single camshaft with two different groups of cam lobes). Alternatively, two separate valve phase shifters could be used to control the timing of the HP exhaust valves 120 independent of the LP exhaust valves 122 to adjust. For example, two separate camshafts could be used with two separate camshaft phasers. A camshaft controls the HP exhaust valves 120 , and the other camshaft controls the LP exhaust valves 122 , Each camshaft would have its own phase shifting device, such as separate camshaft phase shifters. There could also be alternative means of phasing the valve timing of the HP and LP exhaust valves 120 . 122 be used. If the HD exhaust valves 120 independent of the LP exhaust valves 122 For example, the phase shifting devices which control their phasing could be of different types for the different types of valves.

The following table is a non-exhaustive list of some different combinations for different phasing / valve timing configurations: Inlet and exhaust control times variable Auslassteuerzeiten variable (EV fixed) All the same (EV + HDAV + NDAV) 2 different timing settings (EV + NDAV independent of HDAV) All valves independent All the same Independently 1 NWPS (1, 2 or 3 camshafts) 2 NWPS (2 or 3 camshafts) 3 NWPS (3 camshafts) 1 NWPS (1 or 2 camshafts) 2 NWPS (2 camshafts) 1 coupled UPM 1 NWPS + 1 rpm 2 NWPS (2 camshafts + 1 rpm) 1 rpm 1 NWPS (1 camshaft) + 1 rpm EH 2 rpm 1 NWPS + 2 RPM EH 2 rpm EM EH 3 rpm EM EH EM EM

In the above table, NWPS stands for a camshaft phase shifter, UPM stands for an independent phase mechanism such as the alternative valve-phase shifters discussed above, EH stands for an electrohydraulic valve-phase shifter, and EM stands for an electromechanical valve-phase shifter.

8th shows a further embodiment of an engine system 200 according to the teachings of the present invention.

The engine system 200 uses a similar split-flow exhaust system like the engine system 100 , with the difference that it is a modified EGR system 230 which allows a discharge of EGR gas. The EGR system 230 has a switching system, which is a switching valve 240 which directs the flow of LP exhaust gas to the LP exhaust manifold 218 is ejected. In this embodiment, the switching valve 240 no EGR valve. The changeover valve 240 is not used to incrementally throttle the EGR, but only to switch to where the EGR gas flows. Therefore, the switching valve is operated only in the states "open" and "closed". The changeover valve does not define a wide range of fluid flow rates, unlike an EGR valve. Furthermore, the changeover valve 240 not be a one-way valve to counteract suction pressure, which is due to the fact that the EGR system 230 not the intake system 204 with the turbocharger 224 coupled.

The EGR system 230 has an upstream channel 242 upstream of the changeover valve 240 on which the LP exhaust gases to the switching valve 240 directs. A first downstream channel 244 connects the changeover valve 240 fluidic with the intake system 204 of the engine system 200 , When the switching valve 240 the upstream channel 242 with the first downstream channel 244 coupled, the LP exhaust gases form EGR gas and become the intake system 204 directed.

A second downstream channel 246 is fluidly between the exhaust outlet 214 and the switching valve 240 arranged. The second downstream channel 246 is between the exhaust outlet 214 and the turbine 226 of the turbocharger 224 coupled. When the switching valve 240 the upstream channel 242 with the second downstream channel 246 coupled, the LP exhaust gases are only via the exhaust outlet 214 from the engine system 200 drained and are not used as EGR gas.

A third downstream channel 248 Optionally available as well. Therefore, this third downstream channel 248 represented by a dashed line. The third downstream channel 248 is fluid between the switching valve 240 and the flow path between the HP exhaust manifold 216 and the turbine 226 arranged. When the switching valve 240 the upstream channel 242 with the third downstream channel 248 coupled, the LP exhaust gases to the turbine 226 directed to by additionally driving the turbocharger 224 to support the generation of a charge.

Also in this case opens and closes the switching valve 240 only individual flow paths and causes no incremental throttling of the flow rate through the individual flow paths between "fully open" and "fully closed". The LP exhaust valves 222 Control the flow of exhaust gases from the cylinders into the LP exhaust manifold 218 and thus to the switching valve 240 , Thus, the switching valve works 240 according to a principle "all or nothing".

The previously described engine systems 100 . 200 are typically used for four-stroke engine systems. However, another embodiment of an engine system 300 in accordance with the invention 9 shown. This engine system 300 is a Uniflow (DC) two-stroke engine.

The engine system 300 is the engine systems described above 100 . 200 similar in many ways, and only the main differences are described.

In this embodiment, the engine system 300 an internal combustion engine 302 on which a number of cylinders 303 includes, in which pistons are arranged. The cylinders 303 communicate with an intake system 304 for receiving intake gases and an exhaust system 312 for exhausting the burned exhaust gases generally away from the internal combustion engine 302 , The exhaust system 312 is a split-flow design with an HP exhaust manifold 316 and a LP exhaust manifold 318 on. An engine designed as a V-type engine (not shown) may include a plurality of HP and / or LP exhaust manifolds, which may or may not be connected.

In this embodiment, the internal combustion engine 302 four movable valves near the top of the combustion chamber. However, all these valves are exhaust valves. More precisely, each cylinder has two HD exhaust valves 320 and two LP exhaust valves 322 on. However, in alternative embodiments, only at least one HP exhaust valve and at least one LP exhaust valve is required. The HD exhaust valves 320 are between the cylinder 303 and the HD exhaust manifold 316 arranged. The LP exhaust valves 322 are between the cylinder 303 and the LP exhaust manifold 318 arranged.

A turbocharger 324 has a turbine 326 inside the exhaust system 312 downstream of the HP exhaust manifold 316 and a compressor 328 within the intake system 304 upstream of the plenum of the intake manifold 308 of the intake system 304 on.

The LP exhaust manifold 318 stands with the intake system 304 through an EGR system 330 in fluid communication.

It is additionally based on the simplified representation of 10 Reference is made; unlike the engine systems described above 100 . 200 be with the internal combustion engine 302 one or more intake ducts 313 used the combustion chamber 317 with the intake manifold 308 fluidly connect to the combustion chamber 317 Feed intake gases. The intake channels 313 are generally near the bottom or bottom of the cylinders (not shown) under the combustion chambers 317 arranged.

As the gases pass through the cylinder 303 and in particular the combustion chamber 317 moving in one direction only, will this engine 312 considered as a Uniflow (DC) engine.

The valve timing and the opening and closing of the intake ports for the engine system 300 are in 11 shown. The working cycle for the internal combustion engine 302 is referring to 11 explained.

Immediately before top dead center ("TDC"), fuel injection begins 340 , After the downward movement of the piston has started, and slightly after TDC, fuel injection is stopped 342 , Then the working stroke takes place 344 wherein the mixture of fuel and intake gases (plus EGR gases) burns and drives the piston toward bottom dead center ("UT"). Open at a crankshaft angle of approximately 100 ° n. OT 346 the HD exhaust valves 320 , When the exhaust valves are open, the piston passes through the intake port 313 at about 135 ° N. OT, and the intake ports open 348 in the sidewall of the cylinder 303 ,

Within a range of 30 ° crankshaft open before to 30 ° after the UT 350 the LP exhaust valves 322 , Within a range up to 30 ° crankshaft after opening the LP exhaust valves 322 shut down 352 the HD exhaust valves 320 , Then close 354 the intake ducts 313 when the piston moves back toward the TDC and the intake ports 313 happens. Shortly after closing the intake ports 313 shut down 356 the LP exhaust valves 322 , At this time, all valves and channels are closed, and there is the compression stroke 358 instead of.

As in the case of a four-stroke engine, the valve timing of the two-stroke HP and LP exhaust valves is varied, in this case either independently or synchronously. The range of valve timing change is typically less than 30 ° crankshaft. A variable geometry turbine is advantageous for maximizing performance. The described various arrangements and mechanisms for adjusting the valve timing can be integrated into the two-stroke engines. However, there is no mechanism for adjusting the timing of the intake since these are a fixed parameter in two-stroke engines.

All references cited herein, including publications, patent applications and patents, are hereby incorporated by reference in the present text to the same extent as if each reference were individually and specifically cited by reference herein and are set forth in their entireties herein.

The use of the terms "a" and "a" and "the" and similar reference words in the context of the description of the invention (in particular in the context of the following claims) is to be construed as including both the singular and the abstract Plural, unless otherwise stated herein or the context does not clearly contradict. The terms "comprising,""having,""including," and "containing" are to be construed as "indefinite" terms (ie, "including, but not limited to,") unless otherwise specified. The indication of ranges of values herein is intended to be merely a shorthand way of referring separately to any particular value that falls within the scope unless otherwise specified herein, and each individual value is included in the description as if individually set forth herein. All methods described herein may be performed in any suitable manner, unless otherwise specified herein or the context clearly not contradicted. The use of any examples or example-based formulation (eg, "such as") herein is merely intended to make the invention better to clarify, and imposes no limitation on the scope of the invention, unless otherwise claimed. No language in the specification may be construed as indicating any unclaimed element as essential to the practice of the invention.

Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variants of these preferred embodiments may become apparent to one of ordinary skill in the art upon reading the foregoing description. The inventors expect those skilled in the art to apply such variations accordingly, and the inventors intend that the invention be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter specified in the appended claims, as the applicable law so permits. In addition, any combinations of the above-described elements in all possible variants thereof are included in the invention, unless stated otherwise or the context is not clearly contradicted.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 6155216 [0098]
• US 2010/0083922 [0099]

Claims (19)

Internal combustion engine system comprising: an engine block defining a combustion cylinder; a gas intake system having an intake manifold; an exhaust system comprising: a high pressure exhaust manifold, at least one high pressure exhaust valve disposed between the cylinder and the high pressure exhaust manifold, and a high pressure exhaust valve control device operably coupled to the at least one high pressure exhaust valve to control the opening and closing of the at least one high pressure exhaust valve; a low pressure exhaust manifold, at least one low pressure exhaust valve disposed between the cylinder and the low pressure exhaust manifold, and a low pressure exhaust valve control device operably coupled to the at least one low pressure exhaust valve to control the opening and closing of the at least one low pressure exhaust valve; a crankshaft; and at least one valve phase displacement device coupled to at least one of the high pressure outlet valve control device and the low pressure outlet valve control device and configured to retard or advance the actuation of at least one of the at least one high pressure outlet valve or the at least one low pressure outlet valve relative to the crankshaft. An internal combustion engine according to claim 1, wherein: the gas intake system further comprises at least one intake valve disposed between the cylinder and the intake manifold, and an intake valve control device operably coupled to the at least one intake valve to control the opening and closing of the intake valve; the at least one valve phase displacement device is also operatively coupled to the inlet valve control device and the at least one valve phase displacement device is also configured to retract or advance the actuation of the at least one inlet valve. 2. The internal combustion engine system of claim 2, wherein the at least one valve phase displacement device comprises a single valve phase displacement device, the single valve phase displacement device is operatively coupled to the inlet valve control device and the low pressure outlet valve control device configured to control actuation of the at least one inlet valve and the at least one inlet valve Simultaneously retract or advance at least one low pressure exhaust valve relative to the crankshaft, and wherein the intake valve control device and the low pressure exhaust valve control device are camshafts and the single valve phase shifter is a single cam phaser. 2. The internal combustion engine system of claim 2, wherein the at least one valve phase displacement device comprises a single valve phase displacement device, the single valve phase displacement device is operably coupled to the inlet valve control device, the high pressure outlet valve control device, and the low pressure outlet valve control device configured to control the actuation of the valve at least one intake valve, the at least one high-pressure exhaust valve and the at least one low-pressure exhaust valve relative to the crankshaft zurückzustellen or vorzuverstellen simultaneously. The internal combustion engine system of claim 4, wherein the inlet valve control device, the high pressure outlet valve control device and the low pressure outlet valve control device are separate cam lobes on a single camshaft and the single valve phase displacement device is a single camshaft phase shifter. The internal combustion engine system of claim 4, wherein the intake valve control device is a first cam lobe on a first camshaft, the high pressure exhaust valve control device is at least a first cam lobe on a second camshaft configured to control the actuation of the at least one high pressure exhaust valve, and the low pressure exhaust valve Control device is at least one second cam lobe on the second camshaft configured to control the actuation of the at least one low pressure outlet valve in a manner other than the at least one first cam lobe controlling the at least one high pressure outlet valve. The internal combustion engine system of claim 6, wherein the engine block defines a plurality of combustion cylinders and the at least one high pressure exhaust valve is a plurality of high pressure exhaust valves, each combustion cylinder having at least one high pressure exhaust valve; wherein the at least one low pressure exhaust valve is a plurality of low pressure exhaust valves, each combustion cylinder having at least one low pressure exhaust valve, and wherein the at least one first cam lobe on the second camshaft is a plurality of first cam lobes associated with the plurality of high pressure exhaust valves At the at least one second cam lobe on the second camshaft is a plurality of second cam lobes. The internal combustion engine system of claim 1, further comprising: a turbocharger having a turbine in the exhaust system in fluid communication with the high pressure exhaust manifold; an exhaust gas recirculation (EGR) system fluidly coupling the low pressure exhaust manifold to the air induction system, the EGR system having no exhaust gas recirculation (EGR) valve disposed between the low pressure exhaust manifold and the air induction system. The system of claim 8, wherein the EGR system comprises an exhaust gas recirculation cooler (EGR cooler). The system of claim 8 further comprising a switching system within the EGR system, wherein the switching system is configured to fluidly connect the low pressure exhaust manifold to the air induction system in a first state and the low pressure exhaust manifold to a downstream exhaust gas in a second state fluidly connecting the turbine, wherein the switching system is incapable of incrementally adjusting the flow rate from the low pressure exhaust manifold to the air induction system through the switching system; or further comprising a switching system within the EGR system, wherein the switching system is configured to fluidly connect the low pressure exhaust manifold to the air induction system in a first state and to fluidly connect the low pressure exhaust manifold to the exhaust system upstream of the turbine in a second state connect, wherein the switching system is not able to adjust its flow rate incrementally. The system of claim 8, wherein the fluidic coupling between the low pressure exhaust manifold and the air induction system is free of valves. The system of claim 8, wherein the low-pressure outlet valve control device is configured to open the low-pressure outlet valve control device at or after a bottom dead center of a piston within the combustion cylinder of a four-stroke engine. A method of controlling exhaust flow from an internal combustion engine system including an intake system; a high pressure exhaust system including a high pressure outlet valve operably fluidly connected to a turbine of a turbocharger; and a low pressure exhaust system including a low pressure exhaust valve operatively connected to the intake system by an exhaust gas recirculation (EGR) system, the method comprising: Driving the turbine with a first exhaust stream flowing through the high pressure exhaust system and having a first thermodynamic characteristic having a first value; and Returning a second exhaust stream to the intake system via the EGR system from the low pressure exhaust system, the second exhaust stream having a second value of the first thermodynamic characteristic, the second value being different from the first value. The method of claim 13, wherein the first thermodynamic characteristic is entropy and the first value is greater than the second value. The method of claim 13, wherein the first value is greater than the second value by at least 50 J / (kg · K). 2. The internal combustion engine system of claim 2, wherein the at least one valve phase displacement device comprises a single valve phase displacement device, the single valve phase displacement device is operably coupled to the inlet valve control device and the low pressure outlet valve control device and configured to control actuation of the at least one inlet valve and the at least one inlet valve simultaneously retracting or advancing at least one low pressure exhaust valve relative to the crankshaft; or wherein the at least one valve phase displacement device with the inlet valve control device, the high pressure outlet valve control device and the low pressure outlet valve control device is operably coupled and adapted to independently retard or advance the actuation of the at least one inlet valve, the at least one high pressure outlet valve, and the at least one low pressure outlet valve relative to the crankshaft. 2. The internal combustion engine system of claim 1, wherein the at least one valve phase displacement device comprises only a single valve phase displacement device operably coupled to the high pressure outlet valve control device and the low pressure outlet valve control device configured to actuate the at least one high pressure outlet valve and the at least one low pressure outlet valve retract or advance simultaneously relative to the crankshaft; or wherein the at least one valve phase displacement device is operably coupled to the high pressure outlet valve control device and the low pressure outlet valve control device and adapted to independently retard or advance the actuation of the at least one high pressure exhaust valve and the at least one low pressure exhaust valve relative to the crankshaft. The method of claim 13, further comprising: Receiving a setpoint of the EGR flow rate; and Phasing the low pressure exhaust valve to provide a flow rate of the second subset of exhaust at a sufficient flow rate and thermodynamic state to supply EGR gas to the intake system at the EGR flow rate setpoint. The method of claim 13, further comprising: Receiving an intake gas pressure setpoint representing a desired intake gas pressure; and Phasing the high pressure exhaust valve based on the intake gas pressure setpoint to provide flow of the first portion of exhaust gas at a sufficient flow rate to drive the turbine with sufficient energy to provide the desired intake gas pressure.

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