Method for estimating engine cylinder variables using second order sliding modes

• US 6,711,489 B2
• Filed: 12/05/2001
• Issued: 03/23/2004
• Est. Priority Date: 12/05/2001
• Status: Expired due to Fees

• Current Assignee: Visteon Global Technologies Incorporated (Visteon Corporation)
• Original Assignee: Visteon Global Technologies Incorporated (Visteon Corporation)
• Inventors: Haskara, Ibrahim, Mianzo, Lawrence A.
• Primary Examiner(s): Wolfe, Willis R.
• Assistant Examiner(s): Hoang, Johnny H.
• Application Number:
  US10/010,849
• Publication Number:
  US 20030105575A1
• Time in Patent Office: 839 Days
• Field of Search: 731/15, 731/16, 731/182, 123/568.14, 701/101, 701/102, 701/108, 701/114
• US Class Current: 701/101
• CPC Class Codes: F02D 2200/0402 the parameter being determined by using a model of the engine intake or its components
• CPC Class Codes: F02D 2200/0406 Intake manifold pressure
• CPC Class Codes: F02D 41/0062 Estimating, calculating or determining the internal EGR rate, amount or flow
• CPC Class Codes: F02D 41/1403 Sliding mode control
• CPC Class Codes: F02D 41/1448 the characteristics being an exhaust gas pressure
• CPC Class Codes: F02D 41/182 for the control of a fuel injection device
• CPC Class Codes: G05B 13/0255 the criterion being a time-optimal performance criterion
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A method for real time estimation of air charge, residual gas, and backflow in an engine cylinder, i.e., in-cylinder variables, by estimating total mass flow into and out of the cylinders. These estimations are then integrated based on starting and ending times for induction strokes of each cylinder to calculate air charge and residual gas for each cylinder. The method uses intake and exhaust manifold pressure measurements to estimate the in-cylinder variables. The intake and exhaust manifold pressure measurements are processed through the ideal gas law to dynamically determine the net change in the amount of gas inside the manifolds in order to estimate the in-cylinder variables on-line.

Claims

1. A method for estimating residual gas in each cylinder of an internal combustion engine, the method comprising:

estimating total mass flow entering into cylinders of the engine by processing intake pressure measurements;

estimating total mass flow exiting from cylinders of the engine by processing exhaust pressure measurements;

determining mass flow into each cylinder by integrating the estimated total mass flow entering into the cylinders based on starting and ending times for induction strokes of each cylinder;

determining mass flow exiting from each cylinder by integrating the estimated total mass flow exiting from the cylinders based on starting and ending times for exhaust strokes of each cylinder; and

determining residual gas in each one of the cylinders by subtracting from the integrally determined mass flow entering into one of the cylinders the integrally determined mass flow exiting from the one of the cylinders.

2. The method of claim 1, wherein the second order sliding mode equation is determined according to the following equations:

3. The method of claim 2, wherein the step of estimating total mass flow entering into the engine cylinders results in the following equation:

${\stackrel{\stackrel{.}{\_}}{m}}_{{\mathrm{ct}}_{\mathrm{in}}}={\stackrel{.}{m}}_t-\frac{V_i}{{\mathrm{RT}}_i}<br><br>u_i$

where {overscore ({dot over (m)})}_ctin is the estimated total mass flow entering the engine cylinders, m_t equals throttle body mass flow, V_i equals intake manifold volume, R equals a universal constant, T_i equals intake manifold temperature, and u_i equals an intermediate variable based on u_i={dot over (σ

)}_i+{dot over (P)}_i.

4. The method of claim 3, wherein estimating total mass flow exiting from the engine cylinders results in the following equation:

${\stackrel{\stackrel{.}{\_}}{m}}_{{\mathrm{ct}}_{\mathrm{out}}}={\stackrel{.}{m}}_e+\frac{V_e}{{\mathrm{RT}}_e}<br><br>u_e$

where {overscore ({dot over (m)})}_ctout is the estimated total mass flow exiting the engine cylinders, m_e equals exhaust mass flow, V_e equals exhaust manifold volume, R equals a universal constant, T_e equals intake manifold temperature, and u_e equals an intermediate variable based on u_e={dot over (σ

)}_e+P_e.

5. The method of claim 4, wherein determining mass flow entering into each cylinder by integrating the estimated total mass flow entering into the cylinders based on starting and ending times for induction strokes of each cylinder results in the following equation:

${\stackrel{\_}{m}}_{{\mathrm{cj}}_{\mathrm{in}}}<br><br>\left[k\right]={\int <br><br>}_{{\mathrm{ts}}_{j_{\mathrm{in}}},k}^{{\mathrm{te}}_{j_{\mathrm{in}}},k}<br><br>{\stackrel{\stackrel{.}{\_}}{m}}_{{\mathrm{ct}}_{\mathrm{in}}}<br><br>\left(\mathrm{\tau <br><br>}\right)<br><br><br><br>\mathrm{\tau <br><br>}$

where ts_jin^,k and te_jin^,k represent the starting and the ending times of the induction strokes for the jth cylinder at the kth step.

6. The method of claim 5, wherein determining mass flow exiting from each cylinder by integrating the estimated total mass flow exiting from the cylinders based on starting and ending times for induction strokes of each cylinder results in the following equation:

${\stackrel{\_}{m}}_{{\mathrm{cj}}_{\mathrm{out}}}<br><br>\left[k\right]={\int <br><br>}_{{\mathrm{ts}}_{j_{e<br><br>\text{\hspace{1em}<br><br>}<br><br>x}},k}^{{\mathrm{te}}_{j_{\mathrm{ex}}},k}<br><br>{\stackrel{\stackrel{.}{\_}}{m}}_{{\mathrm{ct}}_{\mathrm{out}}}<br><br>\left(\mathrm{\tau <br><br>}\right)<br><br><br><br>\mathrm{\tau <br><br>}$

where ts_jin^,k and te_jin^,k represent the starting and the ending times of the induction strokes for the jth cylinder at the kth step.

7. The method of claim 6, wherein determining residual gas in each cylinder by subtracting from the integrally determined mass flow entering into one of the cylinders the integrally determined mass flow exiting from the one of the cylinders results in the following equation:

8. The method of claim 1, wherein determining residual gas in each one of the cylinders includes subtracting from the integrally determined mass flow entering into one of the cylinders the integrally determined mass flow exiting from the one of the cylinders and adding the fuel mass entering into the one of the cylinders.

9. A method for estimating air charge in each cylinder of an internal combustion engine, the method comprising:

using second order sliding modes to differentiate intake and exhaust pressures;

estimating total mass flow entering into cylinders of the engine by processing the intake and exhaust pressures; and

determining mass flow into each cylinder by integrating the estimated total mass flow entering into the cylinders based on starting and ending times for induction strokes of each cylinder.

10. The method of claim 9 wherein, the second order sliding mode equation is determined according to the following equations:

11. The method of claim 10, wherein the step of estimating total mass flow entering into the engine cylinders results in the following equation:

${\stackrel{\stackrel{.}{\_}}{m}}_{{\mathrm{ct}}_{\mathrm{in}}}={\stackrel{.}{m}}_t-\frac{V_i}{{\mathrm{RT}}_i}<br><br>u_i$

where {overscore ({dot over (m)})}_ctin is the estimated total mass flow entering the engine cylinders, m_t equals throttle body mass flow, V_i equals intake manifold volume, R equals a universal constant, T_i equals intake manifold temperature, and u_i equals an intermediate variable based on u_i={dot over (σ

)}_i+P_i.

12. The method of claim 11, wherein determining mass flow entering into each cylinder by integrating the estimated total mass flow entering into the cylinders based on starting and ending times for induction strokes of each cylinder results in the following equation:

${\stackrel{\_}{m}}_{{\mathrm{cj}}_{\mathrm{in}}}<br><br>\left[k\right]={\int <br><br>}_{{\mathrm{ts}}_{j_{\mathrm{in}}},k}^{{\mathrm{te}}_{j_{\mathrm{in}}},k}<br><br>{\stackrel{\stackrel{.}{\_}}{m}}_{{\mathrm{ct}}_{\mathrm{in}}}<br><br>\left(\mathrm{\tau <br><br>}\right)<br><br><br><br>\mathrm{\tau <br><br>}$

where ts_jin^,k and te_jin^,k represent the starting and the ending times of the induction strokes for the jth cylinder at the kth step.

13. The method of claim 9 further comprising:

estimating total mass flow exiting from cylinders of the engine;

determining mass flow exiting from each cylinder by integrating the estimated total mass flow exiting from the cylinders based on starting and ending times for induction strokes of each cylinder; and

determining residual gas in each one of the cylinders by subtracting from the integrally determined mass flow entering into one of the cylinders the integrally determined mass flow exiting from the one of the cylinders.