Engine assembly for a vehicle having a hydrocarbon trap

Patent metadata

Field	Value
Publication number	US-12071887-B2
Application number	US-202118255917-A
Country	US
Kind code	B2
Filing date	Dec 17, 2021
Priority date	Dec 17, 2020
Publication date	Aug 27, 2024
Grant date	Aug 27, 2024

Abstract

An engine assembly for a vehicle includes an internal combustion engine and an exhaust system. The exhaust system includes a catalytic converter, a main muffler, a hydrocarbon trap, a pre-muffler disposed upstream from the main muffler and the hydrocarbon trap, and an exhaust path valve. The exhaust path valve is movable between first and second exhaust path positions. The exhaust path valve obstructs a second exhaust path in the first exhaust path position such that exhaust gas flows from an exhaust port of an engine cylinder to the catalytic converter to the main muffler and to the atmosphere. The exhaust path valve obstructs a first exhaust path in the second exhaust path position such that exhaust gas flows from the exhaust port of the engine cylinder to the catalytic converter to the hydrocarbon trap and to the atmosphere.

First claim

What is claimed is:

1. An engine assembly for a vehicle, comprising:
an internal combustion engine comprising:
a crankcase;
a crankshaft disposed at least in part in the crankcase; and
a cylinder block connected to the crankcase,
the cylinder block defining at least one cylinder, each of the at least one cylinder defining an exhaust port for discharging exhaust gas therefrom;

and
an exhaust system for discharging exhaust gas from the engine, the exhaust system defining a first exhaust path and a second exhaust path separate from one another, the exhaust system comprising:
a catalytic converter in fluid communication with the exhaust port of the at least one cylinder to receive exhaust gas therefrom;
a main muffler downstream from and in selective fluid communication with the catalytic converter, the main muffler defining at least in part the first exhaust path;
a hydrocarbon trap downstream from and in selective fluid communication with the catalytic converter, the hydrocarbon trap defining at least in part the second exhaust path, the hydrocarbon trap comprising a hydrocarbon trapping material to adsorb hydrocarbon from exhaust gas flowing therethrough;
a pre-muffler disposed upstream from the main muffler and the hydrocarbon trap, the pre-muffler defining a pre-muffler chamber, the catalytic converter being in fluid communication with the pre-muffler chamber such that exhaust gas flows from the catalytic converter to the pre-muffler chamber before flowing through one of the first exhaust path and the second exhaust path,
the pre-muffler further comprising:
a muffler conduit to fluidly connect the pre-muffler to the main muffler, and
a trap conduit to fluidly connect the pre-muffler to the hydrocarbon trap; and

at least one exhaust path valve operable to selectively obstruct the first exhaust path and the second exhaust path to prevent exhaust gas from the catalytic converter flowing through the first exhaust path and the second exhaust path respectively, the pre-muffler enclosing the at least one exhaust path valve, each of the at least one exhaust path valve being movable between a first exhaust path position and a second exhaust path position,
the at least one exhaust path valve obstructing the second exhaust path in the first exhaust path position such that exhaust gas flows from the exhaust port of the at least one cylinder to the catalytic converter to the main muffler and to the atmosphere,
the at least one exhaust path valve obstructing the first exhaust path in the second exhaust path position such that exhaust gas flows from the exhaust port of the at least one cylinder to the catalytic converter to the hydrocarbon trap and to the atmosphere,

in the first exhaust path position, the at least one exhaust path valve blocking an inlet of the trap conduit,
in the second exhaust path position, the at least one exhaust path valve blocking an inlet of the muffler conduit.

2. The engine assembly of claim 1 , wherein:
the pre-muffler chamber is a first pre-muffler chamber;
the pre-muffler defining a second pre-muffler chamber in fluid communication with the first pre-muffler chamber;
an outlet of the catalytic converter opens into the first pre-muffler chamber; and
the at least one exhaust path valve is disposed in the second pre-muffler chamber.

3. The engine assembly of claim 1 , wherein the at least one exhaust path valve is a single exhaust path valve comprising:
a valve shaft pivotable about a valve shaft axis;
a first plate member connected to the valve shaft, the first plate member blocking the inlet of the trap conduit in the first exhaust path position of the exhaust path valve; and
a second plate member connected to the valve shaft opposite the first plate member, the second plate member blocking the inlet of the muffler conduit in the second exhaust path position of the exhaust path valve.

4. The engine assembly of claim 1 , wherein:
the exhaust system further comprises a valve actuator operatively connected to the at least one exhaust path valve to move the at least one exhaust path valve between the first exhaust path position and the second exhaust path position;
the engine assembly further comprises a controller in communication with the valve actuator to control movement of the at least one exhaust path valve therethrough; and
the controller is operable to control the valve actuator to move the at least one exhaust path valve to be in the first exhaust path position or the second exhaust path position based at least partly on at least one of:
a rate of fuel consumption of the engine;
a temperature of a part of the engine assembly;
an amount of time elapsed since starting of the engine;
an amount of oxygen contained in exhaust gas discharged by the engine; and
a position of a throttle valve of an air intake system of the engine assembly.

5. The engine assembly of claim 4 , wherein:
the controller is operable to control the valve actuator to move the at least one exhaust path valve to be in the first exhaust path position or the second exhaust path position based at least partly on the temperature of the part of the engine assembly; and
the part of the engine assembly is the catalytic converter.

6. The engine assembly of claim 1 , wherein the exhaust system further comprises an exhaust pipe fluidly connected between the catalytic converter and the exhaust port of the engine, the exhaust pipe comprising an expanding section, a diameter of the exhaust pipe increasing along the expanding section as the exhaust pipe extends away from the exhaust port of the at least one cylinder.

7. The engine assembly of claim 1 , wherein:
the at least one cylinder defines an intake port;
the crankcase is not in fluid communication with the intake port of the at least one cylinder; and the engine operates on a two-stroke engine cycle.

8. A vehicle comprising the engine assembly of claim 1 .

9. An engine assembly for a vehicle, comprising:
an internal combustion engine comprising:
a crankcase;
a crankshaft disposed at least in part in the crankcase; and
a cylinder block connected to the crankcase,
the cylinder block defining at least one cylinder, each of the at least one cylinder defining an exhaust port for discharging exhaust gas therefrom;

and
an exhaust system for discharging exhaust gas from the engine, the exhaust system defining a first exhaust path and a second exhaust path separate from one another, the exhaust system comprising:
a catalytic converter in fluid communication with the exhaust port of the at least one cylinder to receive exhaust gas therefrom;
a main muffler downstream from and in selective fluid communication with the catalytic converter, the main muffler defining at least in part the first exhaust path;
a hydrocarbon trap downstream from and in selective fluid communication with the catalytic converter, the hydrocarbon trap defining at least in part the second exhaust path, the hydrocarbon trap comprising a hydrocarbon trapping material to adsorb hydrocarbon from exhaust gas flowing therethrough;
a pre-muffler disposed upstream from the main muffler and the hydrocarbon trap, the pre-muffler defining a pre-muffler chamber, the catalytic converter being in fluid communication with the pre-muffler chamber such that exhaust gas flows from the catalytic converter to the pre-muffler chamber before flowing through one of the first exhaust path and the second exhaust path; and
at least one exhaust path valve operable to selectively obstruct the first exhaust path and the second exhaust path to prevent exhaust gas from the catalytic converter flowing through the first exhaust path and the second exhaust path respectively, the pre-muffler enclosing the

Assignees

• Brp Rotax Gmbh & Co Kg

Inventors

• Rokita Ralf
• Zarhuber Matthias
• Raffelsberger Christian
• Kusel Heinz
• Foxhall Nigel
• Doppelbauer Markus
• Zorn Thomas
• Schwab Christian

Classifications

• F01N2900/08

  said parameters being related to the engine · CPC title

• F01N3/28

  Construction of catalytic reactors · CPC title

• F01N1/165

  for adjusting flow area · CPC title

• F01N1/083

  using transversal baffles defining a tortuous path for the exhaust gases or successively throttling exhaust gas flow · CPC title

• Y02T10/40

  Engine management systems · CPC title