Engine torque control with fuel mass

• US 9,689,339 B2
• Filed: 06/10/2015
• Issued: 06/27/2017
• Est. Priority Date: 06/10/2015
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Rajagopalan, Sai S. V., Chang, Chen-Fang, Kang, Jun-Mo, Guralp, Orgun A., Yun, Hanho, Najt, Paul M.
• Primary Examiner(s): Vilakazi, Sizo
• Assistant Examiner(s): KIRBY, BRIAN R
• Application Number:
  US14/735,660
• Publication Number:
  US 20160363085A1
• Time in Patent Office: 748 Days
• Field of Search: 123 9015, 123198 F, 12340623, 701103, 701104, 701 54, 701 84, 60285
• CPC Class Codes: F02D 2041/1433 using a model or simulation of the system
• CPC Class Codes: F02D 2200/0406 Intake manifold pressure
• CPC Class Codes: F02D 29/02 peculiar to engines driving vehicles; peculiar to engines driving variable pitch propellers
• CPC Class Codes: F02D 35/023 by determining the cylinder pressure
• CPC Class Codes: F02D 41/14 Introducing closed-loop corrections
• CPC Class Codes: F02D 41/1448 the characteristics being an exhaust gas pressure
• CPC Class Codes: F02D 41/1497 With detection of the mechanical response of the engine
• CPC Class Codes: F02D 41/3011 according to or using specific or several modes of combustion
• CPC Class Codes: F02D 41/3035 a mode being the premixed charge compression-ignition mode

Abstract

An engine assembly includes an internal combustion engine with an engine block having at least one cylinder. An intake manifold and an exhaust manifold are each fluidly connected to the at least one cylinder and define an intake manifold pressure (p_i) and an exhaust manifold pressure (p_e), respectively. A controller is operatively connected to the internal combustion engine and configured to receive a torque request (T_R). The controller is programmed to determine a desired fuel mass (m_f) for controlling a torque output of the internal combustion engine. The desired fuel mass (m_f) is based at least partially on the torque request (T_R), the intake and exhaust manifold pressures and a pressure-volume (PV) diagram of the at least one cylinder.

Claims

1. An engine assembly comprising:

an internal combustion engine including an engine block having at least one cylinder, at least one piston moveable within the at least one cylinder;

an intake manifold and an exhaust manifold, each fluidly connected to the at least one cylinder and defining an intake manifold pressure (p_i) and an exhaust manifold pressure (p_e), respectively;

at least one intake valve and at least one exhaust valve each in fluid communication with the at least one cylinder and having respective open and closed positions;

a fuel injector in fluid communication with the at least one cylinder;

wherein the at least one cylinder defines a plurality of cylinder volumes (V), including a second cylinder volume (V_EVO) when the exhaust valve is in the respective open position;

a controller operatively connected to the internal combustion engine and configured to receive a torque request (T_R), the intake manifold pressure and the exhaust manifold pressure;

wherein the controller is programmed to;

obtain a log-scaled pressure-volume (PV) diagram of the at least one cylinder based at least partially on the intake manifold pressure (p_i) and the exhaust manifold pressure (p_e);

obtain a first function (F₁) as a sum of respective geometrical areas of a plurality of geometrical shapes in the log-scaled pressure-volume (PV) diagram of the at least one cylinder;

obtain a second function (F₂) as a sum of the first function (F₁) and a product of the request (T_R) and pi (π

) such that F₂=F₁+(T_R*π

);

obtain a third function (F₃) based at least partially on a cylinder clearance volume (V_c), the second cylinder volume (V_EVO) and a predefined first constant (γ

) such that F₃=[1−

(V_EVO/V_C)^1-γ

];

determine a desired fuel mass (m_f) based at least partially on the torque request (T_R), the first function (F₁), the second function (F₂) and the third function (F₃); and

control a torque output of the internal combustion engine by injecting the desired fuel mass into the at least one cylinder, via the fuel injector.

2. The engine assembly of claim 1,

wherein the a plurality of cylinder volumes (V) includes:

a first cylinder volume (V_EVC) when the exhaust valve is in the respective closed position, a third cylinder volume (V_IVO) when the intake valve is in the respective open position; and

a fourth cylinder volume (V_IVC) when the intake valve is in the respective closed position.

3. The engine assembly of claim 2, wherein:

the first function (F₁) is defined as F₁=(A_R+A_T1+A_T2;

wherein A_R is an area of a rectangle in the log-scaled pressure-volume (PV) diagram; and

wherein A_T1 and A_T2 are respective areas of a first and a second triangle in the log-scaled pressure-volume (PV) diagram.

4. The engine assembly of claim 3, wherein the area of the rectangle (A_R) is based at least partially on the intake manifold pressure (p_i), the exhaust manifold pressure (p_e), the first cylinder volume (V_EVC), the second cylinder volume (V_EVO) and the third cylinder volume (V_IVO).

5. The engine assembly of claim 3, wherein the area of the first triangle (A_T1) is based at least partially on the intake manifold pressure (p_i), the exhaust manifold pressure (p_e), the first cylinder volume (V_EVC) and the third cylinder volume (V_IVO).

6. The engine assembly of claim 3, wherein the area of the second triangle (A_T2) is based at least partially on the intake manifold pressure (p_i), the exhaust manifold pressure (p_e), the second cylinder volume (V_EVO) and the fourth cylinder volume (V_IVC).

7. The engine assembly of claim 1, wherein:

the desired fuel mass (m_f) is based at least partially on the second function (F₂), the third function (F₃), a predefined second constant (η

) and a predefined third constant (Q_LHV) such that m_f=F₂/(F₃*η

*Q_LHV).

8. A method for controlling torque output in an engine assembly with a desired fuel mass (m_f), the engine assembly including an internal combustion engine having an engine block with at least one cylinder, at least one piston moveable within the at least one cylinder;

at least one intake valve and at least one exhaust valve each in fluid communication with the at least one cylinder and having respective open and closed positions, a fuel injector in fluid communication with the at least one cylinder, and a controller configured to receive a torque request (T_R), an intake manifold pressure, and an exhaust manifold pressure, the method comprising;

obtaining a log-scaled pressure-volume (PV) diagram of the at least one cylinder based at least partially on the intake manifold pressure (p_i) and the exhaust manifold pressure (p_e);

obtaining a first function (F₁), via the controller, as a sum of respective geometrical areas of a plurality of geometrical shapes in the pressure-volume (PV) diagram such that (F₁=A_R+A_T1+A_T2);

wherein A_R is an area of a rectangle in the log-scaled pressure versus volume (PV) diagram of the at least one cylinder;

wherein A_T1 and A_T2 are respective areas of a first and a second triangle in the log-scaled pressure versus volume (PV) diagram;

obtaining a second function (F₂) as a sum of the first function (F₁) and a product of the torque request (T_R) and pi (π

) such that F₂=F₁+(T_R*π

);

obtaining a third function (F₃) based at least partially on a cylinder clearance volume (V_c), a second cylinder volume (V_EVO) when the at least one exhaust valve is in the respective open position and a predefined first constant (γ

) such that F₃=[1−

(V_EVO/V_C)<sup>1-γ

];</sup>

obtaining a desired fuel mass based at least partially on the torque request, the first function (F₁), the second function (F₂) and the third function (F₃); and

controlling the torque output of the engine by injecting the desired fuel mass into the at least one cylinder, via the fuel injector.

9. The method of claim 8, wherein the area of the rectangle (A_R) is based at least partially on the intake manifold pressure (p_i), the exhaust manifold pressure (p_e), a first cylinder volume (V_EVC) when the exhaust valve is in the respective closed position, the second cylinder volume (V_EVO) and a third cylinder volume (V_IVO) when the intake valve is in the respective open position.

10. The method of claim 8, wherein the area of the first triangle (A_T1) is based at least partially on the intake manifold pressure (p_i), the exhaust manifold pressure (p_e), a first cylinder volume (V_EVC) when the exhaust valve is in the respective closed position and a third cylinder volume (V_IVO) when the intake valve is in the respective open position.

11. The method of claim 8, wherein the area of the second triangle (A_T2) is based at least partially on the intake manifold pressure (p_i), the exhaust manifold pressure (p_e), the second cylinder volume (V_EVO) and a fourth cylinder volume (V_IVC) when the intake valve is in the respective closed position.

12. The method of claim 8, wherein:

the desired fuel mass (m_f) is based at least partially on the second function (F₂), the third function (F₃), a predefined second constant (η

) and a predefined third constant (Q_LHV) such that m_f=F₂/(F₃*η

*Q_LHV).

13. A method for controlling torque output in a vehicle with a desired fuel mass (m_f), the vehicle including an internal combustion engine having an engine block with at least one cylinder, at least one piston moveable within the at least one cylinder;

a fuel injector in fluid communication with the at least one cylinder;

at least one intake valve and at least one exhaust valve each in fluid communication with the at least one cylinder and having respective open and closed positions, and a controller configured to receive a torque request (T_R), an intake manifold pressure, and an exhaust manifold pressure, the method comprising;

obtaining a first function (F₁), via the controller, as a sum of respective geometrical areas of a plurality of geometrical shapes in the log-scaled pressure-volume (PV) diagram of the at least one cylinder;

obtaining a second function (F₂), via the controller, as a sum of the first function (F₁) and a product of the torque request (T_R) and pi (π

) such that F₂=F₁+(T_R *π

);

obtaining a third function (F₃), via the controller, based at least partially on a cylinder clearance volume (V_c), a second cylinder volume (V_EVO) when the exhaust valve is in the respective open position and a predefined first constant (γ

) such that F₃=[1−

(V_EVO/V_C)^1-γ

];

obtaining the desired fuel mass (m_f), via the controller, based at least partially on the second function (F₂), the third function (F₃), a predefined second constant (η

) and a predefined third constant (Q_LHV) such that m_f=F₂/( F₃*η

* Q_LHV); and

controlling the torque output of the internal combustion engine by injecting the desired fuel mass into the at least one cylinder, via the fuel injector.