Four-stroke watercraft from Honda

Anti-corrosion treatments for the die-cast aluminum components of Honda's AquaTrax personal watercraft include Alodine/Alumite chromate surface plating with an addidional Superlac top-coat for exterior components and epoxy-resin-based primer applied to coolant-exposed parts before plating.

American Honda Motor Co. has manufactured marine engines of only four-stroke design since 1973 because, it says, the engines are 90% cleaner and up to 50% more fuel-efficient than traditional two-stroke outboard engines. According to the company, its all-new 2002 AquaTrax F-12 and F-12X are the first four-stroke-powered watercraft to meet both the 2006 emissions standards of the Environmental Protection Agency (EPA) and the California Air Resources Board (CARB) 2004 Two-Star Very Low Emissions standards. The 2006 EPA standards set a 75% emissions reduction compared to conventional carbureted two-stroke engines, while engines that meet the CARB Two-Star standard produce 20% less emissions than engines meeting the 2006 EPA standards.

Both watercraft use a new purpose-built, inline, four-cylinder engine that employes liquid cooling and fuel injection. A water-cooled turbocharger produces a maximum boost of 90 kPa (13 psi) to generate 32% more power than a normally aspirated engine. With the turbocharger, the AquaTrax F-12X is rated at 123-kW (165-hp) . The turbine bearing is an enclosed, ceramic-ball design that withstands sustained high-speed compressor operation while providing "nearly" vibration- and friction-free performance. The water-cooled intercooler assures a denser intake charge to provide maximum power and combustion efficiency. The non-turbo engines in the F12 delivers 93-kW (125-hp).

An electronic control unit (ECU) monitors atmospheric pressure, boost pressure, engine speed, cylinder head temperature, and an engine-knock sensor to manage an electronic waste gate valve that controls turbocharger boost, protecting vital engine components. Forged pistons and connecting rods are designed to withstand the rigors of turbocharging. The top piston ring land is anodized, and a chrome-plated top ring further enhances durability.

The 235-cm³ engine has a DOHC, 16-valve configuration, with a one-piece upper-crankcase cylinder block engineered to withstand the rigors of marine duty. The four-valve cylinder head design of the engine has a narrow, 30° included valve angle to create a compact combustion chamber for optimum efficiency and power output at all speed levels. The engine has a 79 x 63 mm (3 x 2.5 in) bore and stroke, and the engine power and pump characteristics are carefully matched for maximum performance without the use of power-robbing gear-reduction systems, moving the AquaTrax F-12 and F-12X to planing speed more rapidly than a conventional two-stroke watercraft—ideal for one-, two- or three-person cruising, sport riding, skiing, and wake-boarding.

The AquaTrax engine features DOHC-actuated valves that use a simple and lightweight cam-over-bucket design.

The crankshaft's main bearings feature a micro-grooved bearing surface to improve oil retention and bearing durability as lateral loading occurs throughout a broad range of operating conditions. Oil jets located on the crankcase main journal castings continually cool piston undersides, ensuring consistent operating temperatures and longer engine life under maximum power. An ECU-controlled off-throttle steering system is provided to help the AquaTrax turn in certain conditions when the handlebars are turned and the throttle is closed. Its air-intake system features an intake port mounted centrally in the hull and a labyrinth airbox construction to keep water out of the engine during normal operation and if the craft is accidentally overturned.

High-pressure programmed fuel injection (PGM-FI) delivers fuel at 300 kPa (43 psi) to four injectors, each mounted in a 38-mm (1.5-in) throttle body. Fuel is delivered through four laser-drilled nozzle tips in each injector, producing a highly combustible air/fuel charge for maximum combustion efficiency and power. The ECU provides two digital 3-D fuel injection maps for each cylinder and one digital 3-D ignition map for cylinder pairs, creating the most suitable fuel-mixture and spark-advance settings. A sophisticated throttle sensor and advanced fuel-injection mapping combine to produce smooth and linear throttle response, responding precisely to minor throttle adjustments.

The vehicle's fast-idling system uses an electric stepping motor to maintain a stable engine idle speed when the engine is cold. An automatic fuel-enriching system is integrated into the PGM-FI module, eliminating the need for a manual choke. Four waterproof, transistorized direct-ignition coils integrate the spark plug cap and the high-tension lead to produce a high-voltage, long-duration spark, providing improved performance at high engine-output levels.

Waterproof instruments on AquaTrax feature LED digital displays for speed, trip distance, travel time, and clock as well as an LED analog display for engine speed and fuel levels.

The engine's cooling system allows water from the jet pump to circulate through two separate circuits to cool the engine and exhaust manifold, ensuring consistent operating temperatures for each system. A three-way coolant coupler and specially designed discharge outlet reduce engine coolant flow during idling and low-speed operation to prevent engine over-cooling, assuring smooth operation and low emissions. A one-way valve permits simplified coolant system flushing.

The dry-sump engine incorporates an oil reservoir mounted adjacent to the cylinder bank. The tank shape and location, together with a specially designed internal multi-baffle system, optimize engine lubrication under a wide variety of operating conditions. An innovative crankcase breather system featuring three breather chambers prevents oil from flowing out of the engine or clogging the breather system if the hull is accidentally overturned.

An axial-flow, single-stage Solas 155-mm (6-in) jet pump with three-blade impeller is matched to the F-12 and F-12X's four-stroke power characteristics. A proprietary Honda impeller design minimizes pump cavitation, resulting in quiet pump operation and extended impeller life.

Storage is available in two sealed compartments with a 87-L (23-gal) front storage box located under the front hood and a smaller, 9.5-L (2.5-gal) compartment located in front of the rider.

The engine is mounted low in the hull, which allows for a low center-of-gravity and improved stability and low- and high-speed turning performance without sacrificing low-speed maneuverability. The lightweight fiberglass reinforced plastic (FRP) hull and deck are joined and permanently sealed at the gunwale. The liner-type FRP inner hull increases hull rigidity more than 200% compared to a single-hull design, according to Honda. Footwell areas have an anti-slip surface for mounting, operating, and dismounting the AquaTrax.

The Honda Ignition Control System (ICS) senses low engine oil pressure and/or abnormally high coolant temperatures and acts to limit or shut off engine operation as necessary. If oil pressure drops below the optimum level, the ICS limits engine speed to 5000 rpm. Extremely low oil pressure stops the engine. If high coolant temperature is detected, a warning light and audible alarm are activated. ICS also shuts off the engine seven seconds after the hull is accidentally overturned.

Rubber engine-mounts feature two-phase damping to simultaneously minimize engine vibration and engine shock when the AquaTrax is traversing large waves. Hand-operated controls include right handlebar-mounted trigger-type throttle control that is operated by pulling the trigger back to increase engine speed and by releasing the lever to return to idle.

Deere maneuvers with a front mower

John Deere's 1565 front mower is the most powerful addition to the company's commercial rotary mower range, which includes the 1435 and 1445 models.

Engineers from John Deere designed the 1565 front mower for commercial cutters and municipal landscapers at work in city parks, golf courses, universities, cemeteries, and other industrial applications. A 55-L (14.5-gal) fuel tank provides for extended mowing times. The machine is powered by a 27-kW (36-hp) direct-injection Yanmar diesel, a CARB-certified engine that is claimed to offer a maximum torque of 105 N•m (77 lb•ft), improved fuel economy, quiet operation, and quick starting.

A self-bleeding fuel system enables the engine to be restarted even if it runs out of fuel. Full-pressure lubrication protects the three-cylinder engine from the rigors of slope and hillside operation, while the design of the machine's high-strength-steel frame allowed for a number of components to be located lower in the machine for increased stability on slants. Other engine features include an air-restriction indicator, a dual-element air cleaner, and a corrosion-free copper/brass rear-mounted radiator that aids in reducing noise levels.

The 1565 has a hydrostatic transmission and dual-speed transaxle with forward mowing speeds of up to 14 km/h (8.5 mph) and transport speeds of 24 km/h (15 mph) at 3400 rpm. The vehicle's standard mechanical four-wheel-drive (FWD) system allows operators to choose between on-demand FWD, full-time FWD, or full-time two-wheel drive. In the on-demand position, FWD automatically engages when needed for additional traction. It also disengages when it is not needed, such as when performing sharp turns and trimming.

The hood of the mower is made of composites, essentially eliminating the possibility of dents, rust, and fading. The vehicle features internal wet disk brakes, and a modulated, hydraulic clutch with brakes provides smooth PTO engagement. Heavy-duty, dual hydraulic-lift cylinders provide vertical and lateral deck float for trailer loading and for clearing 200-mm (8-in) curbs. A 55-A alternator adds to the mower's power.

The mower is available with 1525- and 1830-mm (60- and 72-in) side-discharge 7-IRON mowing decks with a unique baffling system that reduces clumping for a more uniform clipping dispersal. The deck features cold-forged spindles that are heat treated for added strength, with spindle housings that are designed out of ribbed cast aluminum with reinforcing gussets for additional cooling surface area and better distribution of loads over a larger area. The height of the cut can be adjusted from 25 to 150 mm (1 to 6 in) in 13-mm (0.5-in) intervals.

The mower also features a deluxe Grammer seat, tilt steering wheel, standard 50-W halogen headlights, and heads-up indicator light. Its standard two-post ROPS can be folded to move in and around low hanging trees.