US 2001/0011532 A1Published application

Two-cycle engine

AssigneeMaruyama Mfg. Co., Inc.

InventorsToshihisa Nemoto, Terutaka Yasuda

Life of this patent

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Abstract

Apparatuses and methods for controlling HC in exhaust, with Schnuerle type 2-cycle engine. When piston reaches near dead center point, the ends of the channel at the bottom end of piston reach from outlet ports and No. 1 transfer ports, and exhaust gas from outlet ports moves to the top of No. 1 transfer ports, and there a specified amount is kept. With scavenging, the pair of No. 1 transfer ports open first to combustion chamber, and the exhaust gas is introduced to combustion chamber, after which the pair of No. 2 transfer ports is opened to combustion chamber, and the air-fuel mixture is introduced to combustion chamber. Exhaust gas first introduced from No. 1 transfer ports creates a reverse eddy, and there is scavenging within combustion chamber, purging gas as it is into exhaust port. Air-fuel mixture introduced later from No. 2 transfer ports is limited in purging, and is kept in combustion chamber.

Claims23

Dependent claims

A two-cycle engine comprising:

a crankcase having a crank chamber;
a fuel intake port in communication with the crankcase, the fuel intake port being configured to provide a fuel mixture having a first fuel mass concentration to the crankcase;
a cylinder having a combustion chamber with an upper end portion, the cylinder being coupled to the crankcase;
an exhaust port in the cylinder;
a first transfer port in communication with the crankcase and the cylinder, the first transfer port having a first opening into the cylinder, the first opening having a first upper edge;
a second transfer port in communication with the crankcase and the cylinder, the second transfer port having a second opening into the cylinder, the second opening having a second upper edge, the second upper edge of the second opening being further away from the upper end portion of the combustion chamber than the first upper edge of the first opening;
a piston reciprocally moveable in the cylinder and positionable to open or close the first and second openings and the exhaust port as the piston reciprocates in the cylinder;
and
a passage in communication with the first transfer port, the passage being configured to introduce a selected gas having a second fuel mass concentration into the first transfer port.

6 more elements

A method for reducing hydrocarbons in exhaust gas from a two-cycle engine, the two-cycle engine having a crankcase with a crank chamber, an intake port in communication with the crankcase, a cylinder having a combustion chamber, the cylinder being coupled to the crankcase, an exhaust port in the cylinder, a first transfer port in communication with the crankcase and the cylinder, the first transfer port having a first opening into the cylinder, a second transfer port in communication with the crankcase and the cylinder, the second transfer port having a second opening into the cylinder, and a piston reciprocally moveable in the cylinder and positionable to open or close the first and second openings and the exhaust port as the piston reciprocates in the cylinder, the method comprising:

moving the piston away from the combustion chamber along a down-stroke;
introducing a first gas having a first fuel mass concentration into the cylinder through the first opening as the piston moves along the down-stroke, and
after introducing the first gas into the cylinder, introducing a second gas having a second fuel mass concentration into the cylinder through the second opening as the piston moves along the down-stroke, the second fuel mass concentration of the second gas being greater than the first fuel mass concentration of the first gas.

Dependencies are inferred from the claim text.

Facts

Application: 09/813,510Filed 20 Mar 2001
Priority: JP H11-32299312 Nov 1999
Published: 9 Aug 2001
Term ends: Not estimatedThe source records don’t support an estimate.

Classification9 codes

F02F 1/22
Other cylinders: characterised by having ports in cylinder wall for scavenging or charging
F02B 25/14
Engines characterised by using fresh charge for scavenging cylinders: using reverse-flow scavenging, e.g. with both outlet and inlet ports…
F02B 25/20
Engines characterised by using fresh charge for scavenging cylinders: means for reducing the mixing of charge and combustion residues or for…
F02B 33/04
Engines with reciprocating-piston pumps; Engines with crankcase pumps: with simple crankcase pumps, i.e. with the rear face of a non-stepped…

Family

Application09/697,011Continuation in part · filed 25 Oct 2000
Application09/697,012Continuation in part · filed 25 Oct 2000
Application09/813,510Continuation in part · filed 20 Mar 2001
US 6,591,793 B2Related patent
US 2001/0011532 A1This patent

From the US filing history. Foreign family members aren’t listed.