An internal combustion engine may include a first piston reciprocatingly disposed in a first cylinder, a combustion chamber fluidly coupled with the first cylinder, and an ignition source at least partially disposed within the combustion chamber. An intake valve may provide selective fluid communication between an intake system and the combustion chamber, an exhaust valve may provide selective fluid communication between an exhaust system and the combustion chamber. A second piston may be reciprocatingly disposed within a second cylinder, configured to draw a fluid into the second cylinder via a fluid inlet, and expel the fluid via a fluid outlet. A pressure accumulator may receive the fluid from the second cylinder and provide a reservoir of pressurized fluid. A crankshaft may be coupled with the first piston and the second piston for rotational motion associated with reciprocating movement of the first piston and the second piston.

Methods are provided for reducing exhaust gas emissions during a cold-start of an engine. In one example, a method may include generating a flame front in an exhaust port of an exhaust system, heating exhaust gas flowing into an emission control device of the exhaust system and thereby expediting the approach to a light-off temperature of the emission control device, and directing the flame front back to the cylinder as part of a combustion stroke of the four-stroke engine cycle.

Timing of HHO gas injection into a 4-stroke engine is optimized based on engine operating parameters to improve fuel economy.

The aim of the present invention is a method for synchronizing an engine comprising at least one movable piston of a four-stroke internal combustion engine, said method comprising a first step (e1) involving initializing a second memory space, a second step (e2) involving waiting for an edge on a fourth signal (CAM_TOT), a fourth step (e4) involving testing the value of a counter (CPT), an eighth step (e8) involving selecting the theoretical angular positions of the slots of the second signal (CAM_IN) relative to the edges of a first signal (CRK) and of the slots of a third signal (CAM_EX) relative to the edges of the first signal (CRK).

A four-stroke internal combustion engine comprising an inlet cam configured to open and close an inlet valve, a No. 1 exhaust cam configured to open and close an exhaust valve, a No. 2 exhaust cam configured to open and close the same exhaust valve, wherein the No. 2 exhaust cam is angularly adjustable relative to the No. 1 exhaust cam in response to input from an operator, so that the No. 2 exhaust cam is able to be selectively engaged; wherein the No. 1 exhaust cam is configured to open and close the exhaust valve during the compression stroke, so that a selected quantity of air drawn in during the intake stroke is expelled during the compression stroke; and wherein the No. 2 exhaust cam is configured to optionally close the exhaust valve when engaged.

An internal combustion engine may include a first piston reciprocatingly disposed in a first cylinder, a combustion chamber fluidly coupled with the first cylinder, and an ignition source at least partially disposed within the combustion chamber. An intake valve may provide selective fluid communication between an intake system and the combustion chamber, and an exhaust valve may provide selective fluid communication between an exhaust system and the combustion chamber. A second piston may be reciprocatingly disposed within a second cylinder. An inlet associated with the second cylinder may be fluidly coupled with the intake system, and an outlet may be fluidly coupled with one or more of the first cylinder and the combustion chamber. A crankshaft may be coupled with the first piston and the second piston for rotational motion associated with reciprocating movement of the first piston and the second piston.

A rotary roller motor is disclosed herein. The rotary roller motor is a four-stroke internal combustion engine, wherein the rotor “rolls” around the inside of the engine block. The rotor is a two-part rotor having an inner part with a shaft and an offset circular lobe, and an outer rotor fit around the lobe. Two barriers are provided around the rotor chamber, a compression/power barrier and an exhaust/intake barrier. The combustion chamber has a non-reversing compression barrier and a compression hold barrier regulating the combustion of gas.

Systems and methods for operating an internal combustion engine that is included in a hybrid vehicle are described. In one example, the internal combustion engine is operated in a two stroke mode during cold starting to increase mass flow to an electrically heated catalyst so that engine emissions may be reduced.

The invention pertains to gas exchange in internal combustion engines using low to zero-emission fuels. The combustion engine has the ability to regulate the quantity of air/fuel mixture in the cylinder using one or more exhaust valve(s) (2) that can have adjustable opening times in order to control the gas exchange in the cylinder so that exhaust and alternatively also air can be expelled into the exhaust system. By reducing the quantity of air and thus the quantity of fuel for each cycle, that combined with reduced compression pressure means that engines can operate with a higher expansion ratio by leaving the exhaust valve(s) (2) open through a part of the compression stroke to reduce the amount of air to the combustion and reduce compression and then pressure rise before combustion. Air volume and gas exchange are regulated by compressor(s) (5) as well as opening and closing of exhaust valve(s) (2) with the exhaust valve control (4); alternatively, also intake valves for 4-stroke engines.

The present invention relates to a two strokes per cycle Scotch Yoke engine that completes four power strokes per revolution per pair of pistons/cylinders by using both sides of each piston as a combustion chamber. This doubles the power to weight ratio over previous scotch yoke engines and quadruples the power to weight ratio over conventional 4 stroke cycle engines. The present invention is capable of operating in and withstanding the forces of either deflagration (subsonic) and pulse detonation (supersonic) cycles, and is capable of homogeneous charge compression ignition. The present invention can also be an internal/external combustion gas/steam hybrid. The present invention can operate under constant volume or constant pressure cycles as well as most thermal cycles of operation (EG the Otto and Diesel cycle). The present invention works best when using a modified Humphrey cycle to achieve homogeneous charge compression ignition pulse detonation engine using constant volume combustion.