Rotary/Wankel Racing Engines

18
ROTARY ENGINES AKSHATH K.M 1 st M Tech Automotive PES Universi Bangalore @7urboCharger

Transcript of Rotary/Wankel Racing Engines

Page 1: Rotary/Wankel Racing Engines

ROTARY ENGINES

AKSHATH K.M1st M Tech AutomotivePES UniversityBangalore@7urboCharger

Page 2: Rotary/Wankel Racing Engines

WANKEL ENGINE• The Wankel engine is a type of IC engine which

uses a rotary design to convert pressure into a rotating motion instead of using reciprocating pistons.

• Felix Wankel, a German engineer, developed the engine bearing his name in the 1950s and 1960s with the help of NSU Motorenwerke AG. He first conceived the idea in 1924 before finally seeing the first prototype at work in 1957.

• Uses a triangular shaped rotor spinning inside an oval-like housing.

• Manufactured mainly by Mazda, currently used in Mazda RX-8.

• Extremely lightweight and small when compared to engines with similar power output.

First DKM Wankel Engine designed by Felix Wankel the DKM 54 (Drehkolbenmotor), at the Deutsches Museum in Bonn, Germany. The rotor and its housing spin.

Page 3: Rotary/Wankel Racing Engines

BASIC PARTS

Page 4: Rotary/Wankel Racing Engines

SO HOW DOES IT WORK?• The Wankel engine works in the same 4-stroke cycle

as the reciprocating piston engine, with the central rotor successively executing the four processes of intake, compression, ignition (combustion) and exhaust inside the trochoid chamber.

• Both types of engines rely on the expansion pressure created by the combustion of the fuel-air mixture, the difference between them derives from the way they harness it to transform it into mechanical force.

• In a rotary combustion engine, this expansion pressure is applied to the flank of the rotor. Because of the rotor’s triangular shape, the inside space of the housing will always be divided in three working chambers. This is fundamentally different from the piston engine, where the four processes take place within each cylinder.

Page 5: Rotary/Wankel Racing Engines

COMPARISON OF THE 4 STROKE CYCLE IN A WANKEL ENGINE & A RECIPROCATING ENGINE

• While a four-stroke piston engine completes one combustion stroke per cylinder for every two rotations of the crankshaft (that is, one-half power stroke per crankshaft rotation per cylinder), each combustion chamber in the Wankel generates one combustion stroke per driveshaft rotation, i.e. one power stroke per rotor orbital revolution and three power strokes per rotor rotation.

• Thus, the power output of a Wankel engine is generally higher than that of a four-stroke piston engine of similar engine displacement in a similar state of tune; and higher than that of a four-stroke piston engine of similar physical dimensions and weight.

Page 6: Rotary/Wankel Racing Engines

• The displacement volume of the rotary engine is usually expressed by the unit chamber volume and by the number of rotors (eg. 654cc x 2). The unit chamber volume represents the difference between the maximum volume and the minimum volume of a working chamber, while the compression ratio is defined as the ratio between the maximum volume and the minimum volume.

Page 7: Rotary/Wankel Racing Engines

COMPARISONReciprocating Engines Rotary Engines

Uses pistons to regulate intake and exhaust of fuel and gas.

Has a spinning rotor that creates three separate chambers and regulates the inflow and outflow of gasses.

All four strokes, intake compression, combustion and exhaust occur in same cylinder.

Each chamber draws in air and fuel, is compressed, ignited and combusted then expelled creating power while at the same time forcing the other two chambers to do the same.

Pistons continually reverse direction creating more wear and tear on the engine .

Rotors move in a continuous direction making it smoother .

Bad power to weight ratio in comparison.

Only about three moving parts creating less friction, so higher RPM.

Page 8: Rotary/Wankel Racing Engines

• A far higher power to weight ratio than a piston engine.• No reciprocating parts.• Runs with almost no vibration.• Not prone to engine-knock.• Far fewer parts than a piston engine.• Cheaper to mass-produce as contains few parts.• Superior breathing, filling the combustion charge in 270 degrees of mainshaft

rotation rather than 180 degrees in a piston engine.• Supplies torques for about two thirds of the combustion cycle rather than one

quarter for a piston engine.• Wider speed range gives greater adaptability.• It can use fuel of wider octane ratings.• It is approximately one third of the size of a piston engine of equivalent power

output.• On some Wankel Engines the sump oil remains uncontaminated by the

combustion process requiring no oil changes.

ADVANTAGES

Page 9: Rotary/Wankel Racing Engines

DISADVANTAGES» Rotor sealing is still a problem as the engine housing has vastly different

temperatures in each separate chamber section.

» The combustion is slow as the combustion chamber is big and moving.

» Less thermodynamically efficient.

» The biggest disadvantage, however, is its considerable fuel consumption. Comparison tests showed that a Mazda RX8 used up more fuel than a heavier V8 engine with over four times the engine displacement, but comparable performance figures.

» The exhaust stream is enriched with unburned mixture and carbon monoxide.

» Poor emissions. As unburnt fuel is in the exhaust stream, emissions requirements are difficult to meet. This problem looks to be overcome by implementing direct fuel injection into the combustion chamber.

Page 10: Rotary/Wankel Racing Engines

MAZDA’S CONTRIBUTION TO WANKEL’S ENGINE

Page 11: Rotary/Wankel Racing Engines

MAZDA WANKEL ENGINE

• Mazda introduced the world’s first twin-rotor rotary engine car in May 1967 with the Cosmo Sport/Mazda 110S model. It featured a 491cc x 2 Wankel engine that developed 110 hp at 7,000 rpm.

• In 1970 Mazda introduced the first automatic transmission on a Wankel-powered engine and three years later the world’s first pick-up truck with a rotary engine.

• Introduced six-port induction system featuring 3 intake ports per rotor chamber to achieve improved fuel consumption by controlling them in three stages.

• Another noteworthy development was the implementation of a two-stage monolithic catalyst.

Page 12: Rotary/Wankel Racing Engines

• Introduced Wankel Engines with Turbo Chargers in 1982. Building on that achievement, Mazda would later adopt the twin-scroll turbo, minimizing the engine’s turbo lag.

20b Mazda street port turbo GT42R20B-REW (Triple`Rotor Twin Turbo)

• Introduced a 3-spark plug ignition system (Mazda 26B) to improve combustion process.

• Introduced 'thermal reactor’ (which is an enlarged chamber in the exhaust manifold) in 1973 to reduce the HC emmissions and improved the fuel efficiency of the thermal reactor system by 40% by the time of introduction of the in 1978.

Page 13: Rotary/Wankel Racing Engines

• In 2003, Mazda introduced the Renesis engine fitted in the RX-8. The Renesis engine relocated the ports for exhaust from the periphery of the rotary housing to the sides, allowing for larger overall ports, better airflow, and further power gains.

• Mazda is still continuing development of the next generation of Wankel engines, the 16X. The company is researching engine laser ignition, eliminating spark plugs, and direct fuel injection to which the Wankel engine is suited. This leads towards a greater rotor eccentricity, equaling a longer stroke in a reciprocating engine, for better elasticity and low rpm torque. These innovations promise to improve fuel consumption and emissions.

Page 14: Rotary/Wankel Racing Engines

• To improve fuel efficiency further Mazda is looking at using the Wankel as a range extender in series-hybrid cars and announced a prototype, the Mazda2 EV

A cut-away of a Wankel engine shown at the Deutsches Museum in Munich, Germany

Page 15: Rotary/Wankel Racing Engines

MAZDA WANKEL ENGINE POWERED SPORTS & RACING CARS

Page 16: Rotary/Wankel Racing Engines

• In the racing world, Mazda has had substantial success with 2-rotor, 3-rotor, and 4-rotor cars.

Sigma MC74

• The Sigma MC74 powered by a Mazda 12A engine was the first engine and only team from outside Western Europe or the United States to finish the entire 24 hours of the 24 Hours of Le Mans race, in 1974.

• Mazda is the only non-piston engine ever to win Le Mans, which the company accomplished in 1991 with their four rotor 787B (2,622 cc or 160 cu in—actual displacement, rated by FIA formula at 4,708 cc or 287 cu in).

787B

Page 17: Rotary/Wankel Racing Engines

• The Mazda RX-8 is the successor to the RX Series and it is powered by a 1.3 L 2 rotor 13B-MSP Renesis/3-rotor 20B-REW Wankel engine.

Mazda RX-8

Page 18: Rotary/Wankel Racing Engines