IPC Classification

Class code (prefix) Descriptions Number of results
F02B 1/00 Engines characterised by fuel-air mixture compression
F02B 1/02 Engines characterised by fuel-air mixture compression with positive ignition
F02B 1/04 Engines characterised by fuel-air mixture compression with positive ignition with fuel-air mixture admission into cylinder
F02B 1/06 Methods of operating
F02B 1/08 Engines characterised by fuel-air mixture compression with positive ignition with separate admission of air and fuel into cylinder
F02B 1/10 Methods of operating
F02B 1/12 Engines characterised by fuel-air mixture compression with compression ignition
F02B 1/14 Methods of operating
F02B 3/00 Engines characterised by air compression and subsequent fuel addition
F02B 3/02 Engines characterised by air compression and subsequent fuel addition with positive ignition
F02B 3/04 Methods of operating
F02B 3/06 Engines characterised by air compression and subsequent fuel addition with compression ignition
F02B 3/08 Methods of operating
F02B 3/10 Engines characterised by air compression and subsequent fuel addition with compression ignition with intermittent fuel introduction
F02B 3/12 Methods of operating
F02B 5/00 Engines characterised by positive ignition
F02B 5/02 Methods of operating
F02B 7/00 Engines characterised by the fuel-air charge being ignited by compression ignition of an additional fuel
F02B 7/02 Engines characterised by the fuel-air charge being ignited by compression ignition of an additional fuel the fuel in the charge being liquid
F02B 7/04 Methods of operating
F02B 7/06 Engines characterised by the fuel-air charge being ignited by compression ignition of an additional fuel the fuel in the charge being gaseous
F02B 7/08 Methods of operating
F02B 9/00 Engines characterised by other types of ignition
F02B 9/02 Engines characterised by other types of ignition with compression ignition
F02B 9/04 Methods of operating
F02B 9/06 Engines characterised by other types of ignition with non-timed positive ignition, e.g. with hot-spots
F02B 9/08 Engines characterised by other types of ignition with non-timed positive ignition, e.g. with hot-spots with incandescent chambers
F02B 9/10 Chamber shapes or constructions
F02B 11/00 Engines characterised by both fuel-air mixture compression and air compression, or characterised by both positive ignition and compression ignition, e.g. in different cylinders
F02B 11/02 Engines characterised by both fuel-air mixture compression and air compression, or characterised by both positive ignition and compression ignition, e.g. in different cylinders convertible from fuel-air mixture compression to air compression or vice versa
F02B 13/00 Engines characterised by the introduction of liquid fuel into cylinders by use of auxiliary fluid
F02B 13/02 Compression ignition engines using air or gas for blowing fuel into compressed air in cylinder
F02B 13/04 Arrangements or adaptations of pumps
F02B 13/06 Engines having secondary air mixed with fuel in pump, compressed therein without ignition, and fuel-air mixture being injected into air in cylinder
F02B 13/08 Arrangements or adaptations of pumps
F02B 13/10 Use of specific auxiliary fluids, e.g. steam, combustion gas
F02B 15/00 Engines characterised by the method of introducing liquid fuel into cylinders and not otherwise provided for
F02B 15/02 Engines characterised by the method of introducing liquid fuel into cylinders and not otherwise provided for having means for sucking fuel directly into cylinder
F02B 17/00 Engines characterised by means for effecting stratification of charge in cylinders
F02B 19/00 Engines characterised by precombustion chambers
F02B 19/02 Engines characterised by precombustion chambers the chamber being periodically isolated from its cylinder
F02B 19/04 Engines characterised by precombustion chambers the chamber being periodically isolated from its cylinder the isolation being effected by a protuberance on piston or cylinder head
F02B 19/06 Engines characterised by precombustion chambers with auxiliary piston in chamber for transferring ignited charge to cylinder space
F02B 19/08 Engines characterised by precombustion chambers the chamber being of air-swirl type
F02B 19/10 Engines characterised by precombustion chambers with fuel introduced partly into pre-combustion chamber, and partly into cylinder
F02B 19/12 Engines characterised by precombustion chambers with positive ignition
F02B 19/14 Engines characterised by precombustion chambers with compression ignition
F02B 19/16 Chamber shapes or constructions not specific to groups
F02B 19/18 Transfer passages between chamber and cylinder
F02B 21/00 Engines characterised by air-storage chambers
F02B 21/02 Chamber shapes or constructions
F02B 23/00 Other engines characterised by special shape or construction of combustion chambers to improve operation
F02B 23/02 Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition
F02B 23/04 Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition the combustion space being subdivided into two or more chambers
F02B 23/06 Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition the combustion space being arranged in working piston
F02B 23/08 Other engines characterised by special shape or construction of combustion chambers to improve operation with positive ignition
F02B 23/10 Other engines characterised by special shape or construction of combustion chambers to improve operation with positive ignition with separate admission of air and fuel into cylinder
F02B 25/00 Engines characterised by using fresh charge for scavenging cylinders
F02B 25/02 Engines characterised by using fresh charge for scavenging cylinders using unidirectional scavenging
F02B 25/04 Engines having ports both in cylinder head and in cylinder wall near bottom of piston stroke
F02B 25/06 Engines having ports both in cylinder head and in cylinder wall near bottom of piston stroke the cylinder-head ports being controlled by working pistons, e.g. by sleeve-shaped extensions thereof
F02B 25/08 Engines with oppositely-moving reciprocating working pistons
F02B 25/10 Engines with oppositely-moving reciprocating working pistons with one piston having a smaller diameter or shorter stroke than the other
F02B 25/12 Engines with U-shaped cylinders, having ports in each arm
F02B 25/14 Engines characterised by using fresh charge for scavenging cylinders using reverse-flow scavenging, e.g. with both inlet and outlet ports arranged near bottom of piston stroke
F02B 25/16 Engines characterised by using fresh charge for scavenging cylinders using reverse-flow scavenging, e.g. with both inlet and outlet ports arranged near bottom of piston stroke the charge flowing upward essentially along cylinder wall opposite the inlet ports
F02B 25/18 Engines characterised by using fresh charge for scavenging cylinders using reverse-flow scavenging, e.g. with both inlet and outlet ports arranged near bottom of piston stroke the charge flowing upward essentially along cylinder wall adjacent the inlet ports, e.g. by means of deflection rib on piston
F02B 25/20 Means for reducing the mixing of charge and combustion residues or for preventing escape of fresh charge through outlet ports, not provided for in, or of interest apart from, groups
F02B 25/22 Means for reducing the mixing of charge and combustion residues or for preventing escape of fresh charge through outlet ports, not provided for in, or of interest apart from, groups by forming air cushion between charge and combustion residues
F02B 25/24 Inlet or outlet openings being timed asymmetrically relative to bottom dead-centre
F02B 25/26 Multi-cylinder engines other than those provided for in, or of interest apart from, groups
F02B 25/28 Multi-cylinder engines other than those provided for in, or of interest apart from, groups with V-, fan-, or star-arrangement of cylinders
F02B 27/00 Use of kinetic or wave energy of charge in induction systems, or of combustion residues in exhaust systems, for improving quantity of charge or for increasing removal of combustion residues
F02B 27/02 Use of kinetic or wave energy of charge in induction systems, or of combustion residues in exhaust systems, for improving quantity of charge or for increasing removal of combustion residues the systems having variable, i.e. adjustable, cross-sectional areas, chambers of variable volume, or like variable means
F02B 27/04 Use of kinetic or wave energy of charge in induction systems, or of combustion residues in exhaust systems, for improving quantity of charge or for increasing removal of combustion residues in exhaust systems only, e.g. for sucking-off combustion gases
F02B 27/06 Use of kinetic or wave energy of charge in induction systems, or of combustion residues in exhaust systems, for improving quantity of charge or for increasing removal of combustion residues in exhaust systems only, e.g. for sucking-off combustion gases the systems having variable, i.e. adjustable, cross-sectional areas, chambers of variable volume, or like variable means
F02B 29/00 INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL - Details thereof
F02B 29/02 Other fluid-dynamic features of induction systems for improving quantity of charge
F02B 29/04 Cooling of air intake supply
F02B 29/06 After-charging, i.e. supplementary charging after scavenging
F02B 29/08 Modifying distribution valve timing for charging purposes
F02B 31/00 Modifying induction systems for imparting a rotation to the charge in the cylinder
F02B 31/02 Modifying induction systems for imparting a rotation to the charge in the cylinder in engines having inlet valves arranged eccentrically to cylinder axis
F02B 31/04 Modifying induction systems for imparting a rotation to the charge in the cylinder by means within the induction channel, e.g. deflectors
F02B 31/06 Movable means, e.g. butterfly valves
F02B 31/08 Modifying induction systems for imparting a rotation to the charge in the cylinder having multiple air inlets
F02B 33/00 Engines characterised by provision of pumps for charging or scavenging
F02B 33/02 Engines with reciprocating-piston pumps; Engines with crankcase pumps
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 working piston acting as sole pumping member in co-operation with the crankcase
F02B 33/06 Engines with reciprocating-piston pumps; Engines with crankcase pumps with reciprocating-piston pumps other than simple crankcase pumps
F02B 33/08 Engines with reciprocating-piston pumps; Engines with crankcase pumps with reciprocating-piston pumps other than simple crankcase pumps with the working-cylinder head arranged between working and pumping cylinders
F02B 33/10 Engines with reciprocating-piston pumps; Engines with crankcase pumps with reciprocating-piston pumps other than simple crankcase pumps with the pumping cylinder situated between working cylinder and crankcase, or with the pumping cylinder surrounding working cylinder
F02B 33/12 Engines with reciprocating-piston pumps; Engines with crankcase pumps with reciprocating-piston pumps other than simple crankcase pumps with the pumping cylinder situated between working cylinder and crankcase, or with the pumping cylinder surrounding working cylinder the rear face of working piston acting as pumping member and co-operating with a pumping chamber isolated from crankcase, the connecting-rod passing through the chamber and co-operating with movable isolating member
F02B 33/14 Engines with reciprocating-piston pumps; Engines with crankcase pumps with reciprocating-piston pumps other than simple crankcase pumps with the pumping cylinder situated between working cylinder and crankcase, or with the pumping cylinder surrounding working cylinder working and pumping pistons forming stepped piston
F02B 33/16 Engines with reciprocating-piston pumps; Engines with crankcase pumps with reciprocating-piston pumps other than simple crankcase pumps with the pumping cylinder situated between working cylinder and crankcase, or with the pumping cylinder surrounding working cylinder working and pumping pistons having differing movements
F02B 33/18 Engines with reciprocating-piston pumps; Engines with crankcase pumps with reciprocating-piston pumps other than simple crankcase pumps with crankshaft being arranged between working and pumping cylinders
F02B 33/20 Engines with reciprocating-piston pumps; Engines with crankcase pumps with reciprocating-piston pumps other than simple crankcase pumps with pumping-cylinder axis arranged at an angle to working-cylinder axis, e.g. at an angle of 90°
F02B 33/22 Engines with reciprocating-piston pumps; Engines with crankcase pumps with reciprocating-piston pumps other than simple crankcase pumps with pumping cylinder situated at side of working cylinder, e.g. the cylinders being parallel
F02B 33/24 Engines with reciprocating-piston pumps; Engines with crankcase pumps with crankcase pumps other than with reciprocating pistons only
F02B 33/26 Four-stroke engines characterised by having crankcase pumps
F02B 33/28 Component parts, details, or accessories of crankcase pumps not provided for in, or of interest apart from, groups
F02B 33/30 Control of inlet or outlet ports
F02B 33/32 Engines with pumps other than of reciprocating-piston type
F02B 33/34 Engines with pumps other than of reciprocating-piston type with rotary pumps
F02B 33/36 Engines with pumps other than of reciprocating-piston type with rotary pumps of positive-displacement type
F02B 33/38 Engines with pumps other than of reciprocating-piston type with rotary pumps of positive-displacement type of Roots type
F02B 33/40 Engines with pumps other than of reciprocating-piston type with rotary pumps of non-positive-displacement type
F02B 33/42 Engines with pumps other than of reciprocating-piston type with driven apparatus for immediate conversion of combustion gas pressure into pressure of fresh charge, e.g. with cell-type pressure exchangers
F02B 33/44 Passages conducting the charge from the pump to the engine inlet, e.g. reservoirs
F02B 35/00 Engines characterised by provision of pumps for sucking combustion residues from cylinders
F02B 35/02 Engines characterised by provision of pumps for sucking combustion residues from cylinders using rotary pumps
F02B 37/00 Engines characterised by provision of pumps driven at least for part of the time by exhaust
F02B 37/02 Gas passages between engine outlet and pump drive, e.g. reservoirs
F02B 37/04 Engines with exhaust drive and other drive of pumps, e.g. with exhaust-driven pump and mechanically-driven second pump
F02B 37/007 Engines characterised by provision of pumps driven at least for part of the time by exhaust with exhaust-driven pumps arranged in parallel
F02B 37/10 Engines with exhaust drive and other drive of pumps, e.g. with exhaust-driven pump and mechanically-driven second pump at least one pump being alternately driven by exhaust and other drive
F02B 37/11 Engines with exhaust drive and other drive of pumps, e.g. with exhaust-driven pump and mechanically-driven second pump at least one pump being alternately driven by exhaust and other drive driven by other drive at starting only
F02B 37/12 Control of the pumps
F02B 37/013 Engines characterised by provision of pumps driven at least for part of the time by exhaust with exhaust-driven pumps arranged in series
F02B 37/14 Control of the pumps of the alternation between exhaust drive and other drive of a pump, e.g. dependent on speed
F02B 37/16 Control of the pumps by bypassing charging air
F02B 37/18 Control of the pumps by bypassing exhaust
F02B 37/20 Control of the pumps by increasing exhaust energy, e.g. using combustion chambers
F02B 37/22 Control of the pumps by varying the cross-section of exhaust passages or air passages
F02B 37/24 Control of the pumps by using pumps or turbines with adjustable guide vanes
F02B 39/00 Component parts, details, or accessories relating to driven charging or scavenging pumps, not provided for in groups
F02B 39/02 Drives of pumps ; Varying pump drive gear ratio
F02B 39/04 Mechanical drives; Variable-gear-ratio drives
F02B 39/06 Mechanical drives; Variable-gear-ratio drives the engine torque being divided by a differential gear for driving a pump and the engine output shaft
F02B 39/08 Non-mechanical drives, e.g. fluid drives having variable gear ratio
F02B 39/10 Non-mechanical drives, e.g. fluid drives having variable gear ratio electric
F02B 39/12 Drives characterised by use of couplings or clutches therein
F02B 39/14 Lubrication of pumps; Safety measures therefor
F02B 39/16 Other safety measures for, or other control of, pumps
F02B 41/00 Engines characterised by special means for improving conversion of heat or pressure energy into mechanical power
F02B 41/02 Engines with prolonged expansion
F02B 41/04 Engines with prolonged expansion in main cylinders
F02B 41/06 Engines with prolonged expansion in compound cylinders
F02B 41/08 Two-stroke compound engines
F02B 41/10 Engines with prolonged expansion using exhaust turbines
F02B 43/00 Engines characterised by operating on gaseous fuels; Plants including such engines
F02B 43/02 Engines characterised by means for increasing operating efficiency
F02B 43/04 Engines characterised by means for increasing operating efficiency for improving efficiency of combustion
F02B 43/06 Engines characterised by means for increasing operating efficiency for enlarging charge
F02B 43/08 Plants characterised by the engines using gaseous fuel generated in the plant from solid fuel, e.g. wood
F02B 43/10 Engines or plants characterised by use of other specific gases, e.g. acetylene, oxyhydrogen
F02B 43/12 Methods of operating
F02B 45/00 Engines characterised by operating on non-liquid fuels other than gas; Plants including such engines
F02B 45/02 Engines characterised by operating on non-liquid fuels other than gas; Plants including such engines operating on powdered fuel, e.g. powdered coal
F02B 45/04 Plants, e.g. having coal-grinding apparatus
F02B 45/06 Engines characterised by operating on non-liquid fuels other than gas; Plants including such engines operating on fuel containing oxidant
F02B 45/08 Engines characterised by operating on non-liquid fuels other than gas; Plants including such engines operating on other solid fuels
F02B 45/10 Engines characterised by operating on non-liquid fuels other than gas; Plants including such engines operating on mixtures of liquid and non-liquid fuels, e.g. in pasty or foamed state
F02B 47/00 Methods of operating engines involving adding non-fuel substances or anti-knock agents to combustion air, fuel, or fuel-air mixtures of engines
F02B 47/02 Methods of operating engines involving adding non-fuel substances or anti-knock agents to combustion air, fuel, or fuel-air mixtures of engines the substances being water or steam
F02B 47/04 Methods of operating engines involving adding non-fuel substances or anti-knock agents to combustion air, fuel, or fuel-air mixtures of engines the substances being other than water or steam only
F02B 47/06 Methods of operating engines involving adding non-fuel substances or anti-knock agents to combustion air, fuel, or fuel-air mixtures of engines the substances being other than water or steam only the substances including non-airborne oxygen
F02B 47/08 Methods of operating engines involving adding non-fuel substances or anti-knock agents to combustion air, fuel, or fuel-air mixtures of engines the substances being other than water or steam only the substances including exhaust gas
F02B 47/10 Circulation of exhaust gas in closed or semi-closed circuits, e.g. with simultaneous addition of oxygen
F02B 49/00 Methods of operating air-compressing compression-ignition engines involving introduction of small quantities of fuel in the form of a fine mist into the air in the engine's intake
F02B 51/00 Other methods of operating engines involving pre-treating of, or adding substances to, combustion air, fuel, or fuel-air mixture of the engines
F02B 51/02 Other methods of operating engines involving pre-treating of, or adding substances to, combustion air, fuel, or fuel-air mixture of the engines involving catalysts
F02B 51/04 Other methods of operating engines involving pre-treating of, or adding substances to, combustion air, fuel, or fuel-air mixture of the engines involving electricity or magnetism
F02B 51/06 Other methods of operating engines involving pre-treating of, or adding substances to, combustion air, fuel, or fuel-air mixture of the engines involving rays or sound waves
F02B 53/00 Internal-combustion aspects of rotary-piston or oscillating-piston engines
F02B 53/02 Methods of operating
F02B 53/04 Charge admission or combustion-gas discharge
F02B 53/06 Valve control therefor
F02B 53/08 Charging, e.g. by means of rotary-piston pump
F02B 53/10 Fuel supply; Introducing fuel to combustion space
F02B 53/12 Ignition
F02B 53/14 Adaptations of engines for driving, or engine combinations with, other devices
F02B 55/00 Internal-combustion aspects of rotary pistons; Outer members for co-operation with rotary pistons
F02B 55/02 Pistons
F02B 55/04 Cooling thereof
F02B 55/06 Cooling thereof by air or other gas
F02B 55/08 Outer members for co-operation with rotary pistons; Casings
F02B 55/10 Cooling thereof
F02B 55/12 Cooling thereof by air or other gas
F02B 55/14 Shapes or constructions of combustion chambers
F02B 55/16 Admission or exhaust passages in pistons or outer members
F02B 57/00 Internal-combustion aspects of rotary engines in which the combusted gases displace one or more reciprocating pistons
F02B 57/02 Fuel or combustion-air supply
F02B 57/04 Control of cylinder-charge admission or exhaust
F02B 57/06 Two-stroke engines or other engines with working-piston-controlled cylinder-charge admission or exhaust
F02B 57/08 Engines with star-shaped cylinder arrangements
F02B 57/10 Engines with star-shaped cylinder arrangements with combustion space in centre of star
F02B 59/00 Internal-combustion aspects of other reciprocating-piston engines with movable, e.g. oscillating, cylinders
F02B 61/00 Adaptations of engines for driving vehicles or for driving propellers; Combinations of engines with gearing
F02B 61/02 Adaptations of engines for driving vehicles or for driving propellers; Combinations of engines with gearing for driving cycles
F02B 61/04 Adaptations of engines for driving vehicles or for driving propellers; Combinations of engines with gearing for driving propellers
F02B 61/06 Combinations of engines with mechanical gearing
F02B 63/00 Adaptations of engines for driving pumps, hand-held tools or electric generators; Portable combinations of engines with engine-driven devices
F02B 63/02 Adaptations of engines for driving pumps, hand-held tools or electric generators; Portable combinations of engines with engine-driven devices for hand-held tools
F02B 63/04 Adaptations of engines for driving pumps, hand-held tools or electric generators; Portable combinations of engines with engine-driven devices for electric generators
F02B 63/06 Adaptations of engines for driving pumps, hand-held tools or electric generators; Portable combinations of engines with engine-driven devices for pumps
F02B 65/00 Adaptations of engines for special uses not provided for in groups or ; Combinations of engines with other devices, e.g. with non-driven apparatus
F02B 67/00 Engines characterised by the arrangement of auxiliary apparatus not being otherwise provided for, e.g. the apparatus having different functions; Driving auxiliary apparatus from engines, not otherwise provided for
F02B 67/04 Engines characterised by the arrangement of auxiliary apparatus not being otherwise provided for, e.g. the apparatus having different functions; Driving auxiliary apparatus from engines, not otherwise provided for of mechanically-driven auxiliary apparatus
F02B 67/06 Engines characterised by the arrangement of auxiliary apparatus not being otherwise provided for, e.g. the apparatus having different functions; Driving auxiliary apparatus from engines, not otherwise provided for of mechanically-driven auxiliary apparatus driven by means of chains, belts, or like endless members
F02B 67/08 Engines characterised by the arrangement of auxiliary apparatus not being otherwise provided for, e.g. the apparatus having different functions; Driving auxiliary apparatus from engines, not otherwise provided for of non-mechanically driven auxiliary apparatus
F02B 67/10 Engines characterised by the arrangement of auxiliary apparatus not being otherwise provided for, e.g. the apparatus having different functions; Driving auxiliary apparatus from engines, not otherwise provided for of charging or scavenging apparatus
F02B 69/00 Internal-combustion engines convertible into other combustion-engine type, not provided for in group ; Internal-combustion engines of different types characterised by constructions facilitating use of same main engine-parts in different types
F02B 69/02 Internal-combustion engines convertible into other combustion-engine type, not provided for in group ; Internal-combustion engines of different types characterised by constructions facilitating use of same main engine-parts in different types for different fuel types, other than engines indifferent to fuel consumed, e.g. convertible from light to heavy fuel
F02B 69/04 Internal-combustion engines convertible into other combustion-engine type, not provided for in group ; Internal-combustion engines of different types characterised by constructions facilitating use of same main engine-parts in different types for different fuel types, other than engines indifferent to fuel consumed, e.g. convertible from light to heavy fuel for gaseous and non-gaseous fuels
F02B 69/06 Internal-combustion engines convertible into other combustion-engine type, not provided for in group ; Internal-combustion engines of different types characterised by constructions facilitating use of same main engine-parts in different types for different cycles, e.g. convertible from two-stroke to four-stroke
F02B 71/00 Free-piston engines; Engines without rotary main shaft
F02B 71/02 Starting
F02B 71/04 Adaptations of such engines for special use; Combinations of such engines with apparatus driven thereby
F02B 71/06 Free-piston combustion gas generators
F02B 73/00 Combinations of two or more engines, not otherwise provided for
F02B 75/00 Other engines, e.g. single-cylinder engines
F02B 75/02 Engines characterised by their cycles, e.g. six-stroke
F02B 75/04 Engines with variable distances between pistons at top dead-centre positions and cylinder heads
F02B 75/06 Engines with means for equalising torque
F02B 75/08 Engines with means for preventing corrosion in gas-swept spaces
F02B 75/10 Engines with means for rendering exhaust gases innocuous
F02B 75/12 Other methods of operation
F02B 75/16 Engines characterised by number of cylinders, e.g. single-cylinder engines
F02B 75/18 Multi-cylinder engines
F02B 75/20 Multi-cylinder engines with cylinders all in one line
F02B 75/22 Multi-cylinder engines with cylinders in V-, fan-, or star-arrangement
F02B 75/24 Multi-cylinder engines with cylinders arranged oppositely relative to main shaft and of "flat" type
F02B 75/26 Engines with cylinder axes coaxial with, or parallel or inclined to, main-shaft axis; Engines with cylinder axes arranged substantially tangentially to a circle centred on main-shaft axis
F02B 75/28 Engines with two or more pistons reciprocating within same cylinder or within essentially coaxial cylinders
F02B 75/30 Engines with two or more pistons reciprocating within same cylinder or within essentially coaxial cylinders with one working piston sliding inside another
F02B 75/32 Engines characterised by connections between pistons and main shafts and not specific to preceding main groups
F02B 75/34 Ultra-small engines, e.g. for driving models
F02B 75/36 Engines with parts of combustion- or working-chamber walls resiliently yielding under pressure
F02B 75/38 Reciprocating-piston engines
F02B 75/40 Other reciprocating-piston engines
F02B 77/00 Component parts, details, or accessories, not otherwise provided for
F02B 77/02 Surface coverings of combustion-gas-swept parts
F02B 77/04 Cleaning of, preventing corrosion or erosion in, or preventing unwanted deposits in, combustion engines
F02B 77/08 Safety, indicating, or supervising devices
F02B 77/10 Safety means relating to crankcase explosions
F02B 77/11 Thermal or acoustic insulation
F02B 77/13 Acoustic insulation
F02B 77/14 Engine-driven auxiliary devices combined into units
F02B 79/00 Running-in of internal-combustion engines