Combustion engine, vehicle comprising the combustion engine and method for controlling the combustion engine

Patent metadata

Field	Value
Publication number	US-2017002702-A1
Application number	US-201415039746-A
Country	US
Kind code	A1
Filing date	Dec 3, 2014
Priority date	Dec 5, 2013
Publication date	Jan 5, 2017
Grant date	—

Abstract

A method to control a four-stroke combustion engine, comprising at least one cylinder; a piston arranged in each cylinder; at least one inlet valve arranged in each cylinder which is connected with an inlet system; at least one first camshaft which controls each inlet valve; at least one exhaust valve arranged in each cylinder which is connected with an exhaust system; at least one second camshaft which controls each exhaust valve; and a crankshaft which controls each camshaft. At least one phase-shifting device is arranged between the crankshaft and the second camshaft, to phase-shift the second camshaft in relation to the crankshaft to a state, where the exhaust valve is controlled in such a way, that it is opened during the expansion stroke of the engine and closed during the exhaust stroke of the engine, to achieve engine braking through compression in the cylinders during the exhaust stroke.

First claim

1 . A four-stroke combustion engine comprising
at least one cylinder; a piston arranged in each cylinder; at least one inlet valve arranged in each cylinder, which inlet valve is connected with an inlet system; at least one first camshaft which controls each inlet valve; at least one exhaust valve arranged in each cylinder, which exhaust valve is connected with an exhaust system; at least one second camshaft which controls each exhaust valve; a crankshaft which controls each camshaft, and at least one phase-shifting device, arranged between the crankshaft and the at least one second camshaft, in order to phase-shift the at least one second camshaft in relation to the crankshaft, to a state where the at least one exhaust valve is controlled in such a way that it is opened during the engine's expansion stroke and closed during the engine's exhaust stroke, in order to achieve engine-braking via compression in the cylinders during the exhaust stroke, and in that a decompression device is connected to the at least one exhaust valve, which decompression device is arranged to open and close the at least one exhaust valve in a transition area between an exhaust stroke and an inlet stroke, when the piston is at a top dead center in the cylinder.

2 . The combustion engine according to claim 1 , wherein the phase shift of the second camshaft may be controlled, to thereby control the compression during the exhaust stroke, for achieving stepless control of the size of the braking torque during engine braking.

3 . The combustion engine according to claim 1 , wherein the at least one second camshaft is arranged to phase-shift corresponding to −60° to −120° crankshaft degrees.

4 . The combustion engine according to claim 1 , wherein the at least one phase-shifting device is also arranged between the crankshaft and the at least one first camshaft, to phase-shift the at least one first camshaft in relation to the crankshaft to a state, where the at least one inlet valve is controlled in such a way, that it is opened at a crankshaft angle where the at least one exhaust valve is closed with the decompression device.

5 . The combustion engine according to claim 1 , wherein the decompression device is adapted to open and close the at least one exhaust valve in the transition area between an inlet stroke and an exhaust stroke, when the piston is at a top dead center in the cylinder.

6 . The combustion engine according to claim 1 , comprising two inlet valves and two exhaust valves arranged in each cylinder.

7 . The combustion engine according to claim 1 , comprising two first and two second camshafts arranged in the combustion engine.

8 . The combustion engine according to claim 1 , comprising a phase-shifting device is arranged for each camshaft.

9 . (canceled)

10 . A vehicle, comprising a combustion engine comprising:
at least one cylinder; a piston arranged in each cylinder; at least one inlet valve arranged in each cylinder, which inlet valve is connected with an inlet system; at least one first camshaft which controls each inlet valve; at least one exhaust valve arranged in each cylinder, which exhaust valve is connected with an exhaust system; at least one second camshaft which controls each exhaust valve; a crankshaft which controls each camshaft; and at least one phase-shifting device, arranged between the crankshaft and the at least one second camshaft, in order to phase-shift the at least one second camshaft in relation to the crankshaft, to a state where the at least one exhaust valve is controlled in such a way that it is opened during the engine's expansion stroke and closed during the engine's exhaust stroke, in order to achieve engine-braking via compression in the cylinders during the exhaust stroke, and in that a decompression device is connected to the at least one exhaust valve, which decompression device is arranged to open and close the at least one exhaust valve in the transition area between an exhaust stroke and an inlet stroke, when the piston is at a top dead center in the cylinder.

11 . A method to control a four stroke combustion engine, where the combustion engine comprises:
at least one cylinder; a piston arranged in each cylinder; at least one inlet valve arranged in each cylinder, which inlet valve is connected with an inlet system; at least one first camshaft which controls each inlet valve; at least one exhaust valve arranged in each cylinder, which exhaust valve is connected with an exhaust system; at least one second camshaft which controls each exhaust valve; and a crankshaft which controls each camshaft,
wherein the method comprises:
a) phase-shifting every second camshaft in relation to the crankshaft, so that every second camshaft is phase-shifted to a state, where the exhaust valve is controlled in such a way, that it is opened during the expansion stroke of the engine and closed during the exhaust stroke of the engine, to achieve engine-braking through compression in the cylinders during the exhaust stroke, and
b) opening and closing the exhaust valve with a decompression device in a transition area between an exhaust stroke and an inlet stroke, when the piston is at a top dead center in the cylinder.

12 . The method according to claim 11 , wherein phase-shifting of every second camshaft may be controlled, to thereby control the compression during the exhaust stroke, for achieving stepless control of the size of the braking torque during engine-braking.

13 . The method according to claim 11 , comprising phase-shifting the at least one second camshaft between −60° and −120° crankshaft degrees.

14 . The method according to claim 11 , comprising:
opening the exhaust valves with the decompression device 40°-80° crankshaft degrees, before the top dead center between the exhaust stroke and the inlet stroke; and closing the at least one exhaust valve with the decompression device 40° 80°, after the top dead center between the exhaust stroke and the inlet stroke.

15 . The method according to claim 14 , further comprising:
c) phase shifting each first camshaft in relation to the crankshaft, so that each first camshaft is phase-shifted to a state, where the inlet valve is controlled in such a way, that it is opened at a crankshaft angle where the exhaust valve is closed with the decompression device.

16 . The method according to claim 15 , wherein the inlet valves in step c) are opened 20°-80° crankshaft degrees, after the top dead center between the exhaust stroke and the inlet stroke.

17 . The method according to claim 11 , wherein in step a) two exhaust valves per cylinder are controlled with the at least one second camshaft.

18 . The method according to claim 11 , wherein in step a) the respective exhaust valves are controlled with two second camshafts.

19 . The method according to claim 11 , wherein in step a) every second camshaft is phase-shifted with a phase-shifting device arranged for every second camshaft.

20 . The method according to claim 11 , wherein the method further comprises before step a), the step of:
d) closing or reducing the fuel supply to at least one of the cylinders.

21 . (canceled)

22 . The method according to claim 11 , further comprising:
e) opening and closing the exhaust valve with a decompression device in the transition area between an inlet stroke and an exhaust stroke, when the piston is at a top dead center in the cylinder.

Assignees

• Scania Cv Ab

Inventors

• Gunnarsson Niclas
• Nyberg Cedric
• Olofsson Eric

Classifications

• F02B2075/027

  four · CPC title

• F01L1/344

  changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear · CPC title

• F01L1/047

  Camshafts · CPC title

• F01L13/06 Primary

  for braking · CPC title

• F02B75/02

  Engines characterised by their cycles, e.g. six-stroke · CPC title