Method for estimating and controlling the intake efficiency of an internal combustion engine

Patent metadata

Field	Value
Publication number	US-11098665-B2
Application number	US-202016874254-A
Country	US
Kind code	B2
Filing date	May 14, 2020
Priority date	May 15, 2019
Publication date	Aug 24, 2021
Grant date	Aug 24, 2021

Abstract

A method for determining the mass m of air trapped in each cylinder of an internal combustion engine comprises determining, a value for each quantity of a first group of reference quantities comprising at least intake pressure P measured inside the intake manifold, engine rotation speed n, mass of gases produced by the combustion in the previous operating cycle (OFF) and present in the cylinder, determining, the actual inner volume V of each cylinder as a function of the engine rotation speed n, of the lift H of the intake valve and of the closing delay angle IVC of the intake valve, and determining the mass m of air trapped in each cylinder as a function of the first group of reference quantities and of the actual volume V inside each cylinder, on the basis of the aforesaid quantities P, V, OFF.

First claim

The invention claimed is:

1. A method for determining the mass (m) of air trapped in each cylinder of an internal combustion engine comprising a number of cylinders, wherein each of the cylinders is connected to an intake manifold from which it receives fresh air through at least one respective intake valve, and to an exhaust manifold into which it introduces the exhaust gases generated by the combustion through at least one respective exhaust valve,
wherein the at least one intake valve is driven so as to vary the lift (H) of the intake valve in controlled manner,
the method comprising the steps of:
determining, based on a filling model using measured and/or estimated physical quantities, a value for each quantity of a first group of reference quantities comprising intake pressure (P) measured inside the intake manifold, engine rotation speed (n), mass of gases produced by the combustion in the previous operating cycle (OFF) and present inside the cylinder estimated as a function of said lift (H) and on the closing delay angle (IVC) of the intake valve depending on said lift (H);
determining, based on said filling model, the effective inner volume (V) of each cylinder as a function of said engine rotation speed (n), of said lift (H) of the intake valve, of said closing delay angle (IVC) of the intake valve and of said intake pressure (P); and
determining the mass (m) of air trapped in each cylinder as a function of the first group of reference quantities and of the actual volume (V) inside each cylinder, through the relation:
m =( P*V )−OFF.

2. The method as set forth in claim 1 , wherein the at least one intake valve is also driven so as to vary the intake valve angular displacement (VVTi) in controlled manner, and/or wherein the at least one exhaust valve is driven so as to vary the exhaust valve angular displacement (VVTe) in controlled manner; and
wherein said step of determining a value for a first group of reference quantities comprises determining said closing delay angle (IVC) of the intake valve based on both the lift (H) of the intake valve and the intake valve angular displacement (VVTi).

3. The method as set forth in claim 2 , further comprising the steps of:
further driving the intake valve by an intake valve phase shifter by varying the intake valve angular displacement (VVTi) in controlled manner so that both the intake valve opening advance angle (IVO) and the intake valve closing delay angle (IVC) not only depend on the lift (H) but also on the intake valve angular displacement (VVTi); and
driving the exhaust valve via an exhaust valve phase shifter by varying the exhaust valve angular displacement (VVTe) in controlled manner so that both the exhaust valve opening advance angle (EVO) and the exhaust valve closing delay angle (EVC) depend on the exhaust valve angular displacement (VVTe).

4. The method as set forth in claim 3 , wherein the step of driving comprises:
determining the intake valve opening advance angle (IVO) using the relation
IVO ( H )= IVO ref −Δivo ( H )− VVTi,

where IVO re f is a reference value of the opening advance angle of the intake valve in the absence of phase shifting, VVTi is the displacement angle of the intake valve phase shifter with respect to a respective reference position corresponding to said reference value IVO ref ;
determining the intake valve closing delay angle (IVC) using the relation
IVC ( H )= IVC ref −Δivc ( H )+ VVTi,

where IVC re f is a reference value of the closing delay angle of the intake valve in the absence of phase shifting;
determining the exhaust valve opening advance angle (EVO) using the relation
EVO=EVO ref −VVTe,

where EVO ref is a reference value of the exhaust valve opening advance angle in the absence of phase shifting and VVTe is the displacement angle of the exhaust valve phase shifter with respect to a respective reference position indicated by said reference value EVO ref ; and
determining the exhaust valve closing delay angle (EVC) using the relation
EVC=EVC ref +VVTe,

where EVC ref is a reference value of the exhaust valve closing delay angle in the absence of phase shifting.

5. The method as set forth in claim 1 , wherein said first group of reference quantities further comprises the temperature (T) detected inside the intake manifold and the temperature (T H2O ) of the coolant fluid of the engine; and
wherein the step of determining the mass (m) of air trapped in each cylinder comprises calculating the mass (m) of air trapped in each cylinder as a function of the first group of reference quantities and of the actual volume (V) inside each cylinder, through the relation:
m =[( P*V )−OFF]* f 1 ( T,P )* f 2 ( T H2O ,P ),

where f 1 (T, P) and f 2 (T H2O , P) are known functions belonging to said filling model.

6. The method as set forth in claim 1 , further comprising the step of:
driving the intake valve via an intake valve lift shifter by varying the law of lift of the intake valve in controlled manner so as to define both the lift (H), and the intake valve opening advance angle (IVO) and the intake valve closing delay angle (IVC) according to one single degree of freedom (γ).

7. The method as set forth in claim 6 , wherein the step of driving comprises:
determining the intake valve opening advance angle (IVO) using the relation
IVO ( H )= IVO hmax −Δivo ( H ),

where IVO′max is the intake valve opening advance angle corresponding to the maximum lift and Δivo(H) is a variation of intake valve opening advance angle depending on the controlled lift (H); and
determining the intake valve closing delay angle (IVC) using the relation
IVC ( H )= IVC hmax −Δivc ( H ),

where IVC hmax is the intake valve closing delay angle corresponding to the maximum lift and Δivc(H) is a variation of intake valve closing delay angle depending on the controlled lift (H).

8. The method as set forth in claim 1 , comprising, if the engine operates under the condition of exhaust gas internal recirculation (EGRi), the further step of:
calculating the combustion chamber volume (Vcc) of the cylinder based on a fourth map f e (TVC, n) which is a function of a first parameter (TVC) and of the engine rotation speed (n), on a fifth map g e (OVL, n) which is a function of a second parameter (OVL) and of the engine rotation speed (n), and on a sixth map h e (H,n) which is a function of the lift (H) and of the engine rotation speed (n),
wherein said first parameter (TVC) is alternatively equal to the closing delay angle (EVC) of the exhaust valve or to the maximum between zero and the minimum value among the closing delay angle (EVC) of the exhaust valve and the value of the opening advance angle (IVO) of the intake valve multiplied by −1, and
wherein said second parameter (OVL) is representative of the duration of the intersecting step between the intake and exhaust curves and is defined as the sum of the exhaust valve closing delay angle (EVC) and the intake valve opening advance angle (IVO).

9. The method as set forth in claim 8 , wherein the combustion chamber volume (V cc ) is calculated using the formula:
V cc =f e ( TVC,n )* g e ( OVL,n )* h e ( H,n ),
where f e , g e , h e are known functions belonging to said filling model.

10. The method as set forth in claim 1 , wherein if the engine may operate under a scavenging condition wherein the intake pressure is greater than the exhaust pressure, thus causing the intake of fresh air which carries away the residual exhaust gases in the combustion chamber, the method comprises the further step of:
calculating the combustion chambe

Assignees

• Marelli Europe Spa

Inventors

• Panciroli Marco

Classifications

• F02D41/0062

  Estimating, calculating or determining the internal EGR rate, amount or flow · CPC title

• F02D2009/0228

  Manifold pressure · CPC title

• F02D2041/001

  for engines with variable valve actuation · CPC title

• F02D9/02

  concerning induction conduits (throttle valves, or arrangements thereof in conduits F02D9/08) · CPC title

• F02D41/0072 Primary

  Estimating, calculating or determining the EGR rate, amount or flow (sensors in EGR systems F02M26/45) · CPC title