Four stroke internal combustion engine

Patent metadata

Field	Value
Publication number	US-11008933-B2
Application number	US-201615772441-A
Country	US
Kind code	B2
Filing date	Oct 5, 2016
Priority date	Nov 3, 2015
Publication date	May 18, 2021
Grant date	May 18, 2021

Abstract

A four stroke internal combustion engine is disclosed comprising at least one cylinder arrangement, an exhaust conduit, and at least one turbine. The cylinder arrangement comprises an exhaust port arrangement configured to open and close an exhaust flow area, ACYL. The cylinder arrangement has a maximum volume, VMAX. The exhaust conduit extends between the exhaust flow area, ACYL, and a turbine wheel inlet area, ATIN, of the turbine and has an exhaust conduit volume, VEXH that is ≤0.5 times the maximum volume, VMAX. The exhaust port arrangement is configured to expose the exhaust flow area, ACYL, at a size of at least 0.22 times the maximum volume, VMAX, when a piston of the cylinder arrangement is at the bottom dead centre, BDC.

First claim

The invention claimed is:

1. A four stroke internal combustion engine comprising:
an exhaust conduit;
a turbine comprising a turbine wheel, the turbine having a turbine wheel inlet area, A TIN ; and
a cylinder arrangement comprising:
a cylinder bore;
a piston arranged to reciprocate in the cylinder bore; and
an exhaust port arrangement, the exhaust port arrangement being configured to open and close an exhaust flow area, A CYL , during an exhaust sequence of the piston reciprocation,
wherein the cylinder arrangement has a maximum volume, V MAX , between a bottom dead center, BDC, of the piston and an upper inner delimiting surface of the combustion chamber,

wherein the exhaust conduit is located between the exhaust flow area, A CYL , and the turbine wheel inlet area, A TIN , and has an exhaust conduit volume, V EXH , that is ≤0.5 times the maximum volume, V MAX , of the cylinder arrangement,
wherein the turbine has a normalized effective flow area, γ, defined as γ=A TURB /V MAX , wherein γ>0.22 m −1 , wherein A TURB =(A TIN /A TOT )*m′ RED *(R/(κ(2/(κ+1) X ))) 1/2 , wherein X=(κ+1)/(κ−1), wherein A TOT is a total inlet area of the turbine, and wherein A TURB is obtained at a reduced mass flow, m′ RED , of the turbine at 2.5-3.5 pressure ratio between an inlet side and an outlet side of the turbine and at a tip speed of 450 m/s of the turbine wheel, and
wherein the exhaust port arrangement is configured to expose the exhaust flow area, A CYL , at a size of at least 0.22 times the maximum volume, V MAX , of the cylinder arrangement when the piston is at the bottom dead center, BDC.

2. The four stroke internal combustion engine according to claim 1 , wherein the value of the exhaust conduit volume, V EXH , of the exhaust conduit located between the exhaust flow area, A CYL , and the turbine wheel inlet area, A TIN , does not include any volume of any conduit connected to the exhaust conduit via a connection having a minimum connection cross section area, A CON , ≤0.022 times the maximum volume, V MAX of the cylinder arrangement.

3. The four stroke internal combustion engine according to claim 1 , wherein the exhaust conduit comprises an inlet and an outlet for fluidly connecting the exhaust flow area, A CYL , with the turbine wheel inlet area, A TIN and does not comprise any other inlets or outlets.

4. The four stroke internal combustion engine according to claim 1 , wherein a momentary cylinder volume, V, of the cylinder arrangement is defined by a selected position of the piston in the cylinder bore during reciprocation of the cylinder and an upper inner delimiting surface of the combustion chamber,
wherein A CYL (V) expresses the exhaust flow area, A CYL , as a function of the momentary cylinder volume, V, during a power stroke of the piston,
wherein an exhaust flow area coefficient, δ, is defined as δ=A CYL (V)/(0.22*V MAX ), A CYL being expressed in m 2 and V MAX being expressed in m 3 ,
wherein the exhaust port arrangement has an opening speed coefficient, β, defined as β=(V(δ=1)−V(δ=0.1))/V MAX , and
wherein the exhaust flow area, A CYL , has an opening speed coefficient β<0.06.

5. The four stroke internal combustion engine according to claim 1 , wherein the turbine wheel is an axial turbine wheel.

6. The four stroke internal combustion engine according to claim 1 , wherein the cylinder arrangement has a total swept volume, V S , in the cylinder bore between the bottom dead center, BDC, and a top dead center, TDC, of the piston, and wherein 0.3<V S <4 liters.

7. A four stroke internal combustion engine comprising:
three cylinder arrangements;
an exhaust conduit arrangement; and
a turbine comprising a turbine wheel, the turbine having a turbine wheel inlet area, A TIN ,
wherein each of the cylinder arrangements comprises:
a combustion chamber;
a cylinder bore;
a piston arranged to reciprocate in the cylinder bore; and
an exhaust port arrangement configured to open and close an exhaust flow area, A CYL , during an exhaust sequence of the piston reciprocation,
wherein the cylinder arrangement has a maximum volume, V MAX between a bottom dead center, BDC, of the piston and an upper inner delimiting surface of the combustion chamber,

wherein the exhaust conduit arrangement comprises three separate exhaust conduits, which each respectively fluidly connects a respective exhaust port arrangement of one of the cylinder arrangements with a separate portion of the turbine wheel inlet area, A TIN , of the turbine, wherein each separate exhaust conduit has a separate exhaust conduit volume, V EXH , that is ≤0.5 times a maximum volume, V MAX ,
wherein the turbine has a normalized effective flow area, γ, defined as γ=A TURB /V MAX , wherein γ>0.22 m −1 , wherein A TURB =(A TIN /A TOT )*m′ RED *(R/(κ(2/(κ+1) X ))) 1/2 , wherein X=(κ+1)/(κ−1), wherein A TOT is a total inlet area of the turbine, and
wherein A TURB is obtained at a reduced mass flow, m′ RED , of the turbine at 2.5-3.5 pressure ratio between an inlet side and an outlet side of the turbine and at a tip speed of 450 m/s of the turbine wheel, and
wherein the exhaust port arrangement is configured to expose the exhaust flow area, A CYL , at a size of at least 0.22 times the maximum volume, V MAX , when the piston is at the bottom dead center, BDC.

8. The four stroke internal combustion engine according to claim 7 , wherein each of the three cylinder arrangements is arranged to fire at an 240-degree crankshaft angle separation interval.

9. The four stroke internal combustion engine according to claim 7 , wherein each of the three cylinder arrangements has an opening speed coefficient β<0.06.

Assignees

• Scania Cv Ab

Inventors

• Olofsson Eric
• Norling Daniel
• Vallinder Michael
• Aspfors Jonas
• Linderyd Johan
• Höglund Henrik
• Larsson Per-Inge
• Dahl Andreas
• Stenberg Martin

Classifications

• F02B37/02 Primary

  Gas passages between engine outlet and pump drive, e.g. reservoirs · CPC title

• F02B37/025

  Multiple scrolls or multiple gas passages guiding the gas to the pump drive · CPC title

• Y02T10/12

  Improving ICE efficiencies · CPC title

• F02C6/12

  Turbochargers, i.e. plants for augmenting mechanical power output of internal-combustion piston engines by increase of charge pressure · CPC title

• F02B27/04 Primary

  in exhaust systems only, e.g. for sucking-off combustion gases · CPC title