Error 404--Not Found

From RFC 2068 Hypertext Transfer Protocol -- HTTP/1.1:

10.4.5 404 Not Found

The server has not found anything matching the Request-URI. No indication is given of whether the condition is temporary or permanent.

If the server does not wish to make this information available to the client, the status code 403 (Forbidden) can be used instead. The 410 (Gone) status code SHOULD be used if the server knows, through some internally configurable mechanism, that an old resource is permanently unavailable and has no forwarding address.

Error 404--Not Found

Error 404--Not Found

From RFC 2068 Hypertext Transfer Protocol -- HTTP/1.1:

10.4.5 404 Not Found

The server has not found anything matching the Request-URI. No indication is given of whether the condition is temporary or permanent.

If the server does not wish to make this information available to the client, the status code 403 (Forbidden) can be used instead. The 410 (Gone) status code SHOULD be used if the server knows, through some internally configurable mechanism, that an old resource is permanently unavailable and has no forwarding address.

Technical Innovations
Honda's CVTs for ATVs


The Honda Hondamatic CVT is housed within a compact, fully sealed assembly and uses the principals of hydrostatic drive, mechanical power transfer, and electronic controls.


The 2001 Honda Fourtrax Foreman Rubicon.


The hydraulic-pump components of Honda's Hondamatic transmission.


The components of the motor of the Hondamatic CVT.

Honda's Hondamatic is a hydromechanical continuously variable transmission (CVT) with a fixed-volume piston pump and a variable-volume piston motor in opposition on the same shaft. It is featured on the 2001 Fourtrax Foreman Rubicon all-terrain vehicle (ATV) and uses an engine to drive the hydraulic pump, forcing hydraulic fluid through sequential pistons. On the other side of the pistons, the pressurized fluid enters a second set of pistons that push against the swash plate. Because the cylinder body holding the pistons is splined to the output shaft, the pressure exerted on the swash plate causes the cylinder body to rotate.

When the angle of the hydraulic motor swash plate is adjusted, the cylinder body (and, therefore, the output shaft) rotates faster or slower, resulting in higher or lower output drive ratios. When either of the two automatic transmission modes is selected, the engine control unit (ECU) continuously monitors input from six sensors to position the motor swash plate at the optimal ratio. Using the ESP mode, the ECU instructs the control motor to move the hydraulic motor plate to preset angles to simulate specific gear selection.

Because the Hondamatic is a closed circuit, any excess hydraulic fluid from the system is recirculated through the transmission using a separate charge pump. The transmission uses standard engine oil as hydraulic fluid.

Upon engagement by the centrifugal clutch, the engine turns the pump outer body, causing the fixed-angle pump swash plate to rotate, sequentially stroking the pump pistons. This action draws low-pressure fluid into the pistons, which discharge high-pressure fluid (corresponding to the input torque). The fluid is distributed to the high-pressure circuit by the pump distributor valve.

The motor distributor valve opens and feeds the high-pressure fluid to the motor piston for the suction stroke. Each distributor valve is eccentrically synchronized to the rotation of its respective swash plate, ensuring that fluid is transferred at the proper time. The amount of fluid discharged depends on the angle of the motor swash plate. The greater the slant, the further the pistons move and the more fluid they transfer. This additional volume transfer makes the motor less efficient, resulting in a differential based on the volume transferred. As the motor pistons travel down the slope of the motor swash plate, the fluid pressure is drawn through the pistons and rotates the motor cylinder body (which houses the pistons). As the cylinder is splined to the output shaft, the output shaft also rotates, transferring power to the drivetrain.

When the motor swash plate is perpendicular to the pump axis, the pistons do not stroke (therefore, oil is not discharged). In this condition, oil cannot flow between the pump and the motor and the motor is hydraulically locked (1:1 gear ratio). An overdrive is achieved by adjusting the swash plate to an angle beyond perpendicularity to the pump axis, creating a drive ratio of 1:0.84.

As the pistons begin their travel back up the motor swash plate, they begin their discharge stroke. The hydraulic fluid is transferred back through the motor distributor valve and into the low-pressure circuit of the body. The fluid then passes through the pump distributor valve, where it is timed to the suction stroke of the pump pistons.

The hydraulic fluid is transferred between the pump and motor piston chambers by distributor valves arranged radially around the shaft. The pump and motor distributor valves are eccentrically arranged on the shaft and are aligned to time the transfer of low- and high-pressure fluid in tune with the direction and inclination of the pump and motor swash plates. As the cylinder rotates, the eccentrically arranged valves slide in and out of the cylinder body, opening and closing the paths in the body.

During normal running, the check valve in the pump cylinder feeds hydraulic fluid into the low-pressure circuit. The check valve is open when the hydraulic pressure in the low-pressure circuit drops below a specified level and, upon achieving the proper pressure, closes to prevent backflow. Under engine compression braking conditions (where the rotational force comes from the wheels), the motor becomes a pump (driven by the input shaft) and the pump becomes a hydraulic motor. In this situation, the high- and low-pressure circuits in the Hondamatic body are reversed. The Hondamatic transmission uses a separate check valve to feed hydraulic fluid to the engine braking low-pressure circuit.

Pressure control valves vent excessive high-pressure fluid into the low-pressure circuit during both normal running and compression braking conditions.

The input reaction force torque from the engine is transmitted to the pistons that are fixed within the rotating cylinder. This force is then transferred through the cylinder to the shaft (mechanical power train). When the ratio is 1:1 and the motor swash plate exerts no reactive force against the motor cylinder, the input torque is transferred directly to output torque with no amplification. When the angle of the swash plate is increased, the reaction force increases, amplifying the output torque. The total output torque is the sum of the input reaction force torque and hydraulic output torque.

The transmission is maximized when combined with the computer-controlled, dual-mode continuously variable change program or the electric shift program (ESP), already in use on the Fourtrax Foreman ES and the Rancher ATVs.

As previously discussed, the output shaft speed is controlled by the angle of the motor swash plate. The position of this swash plate is determined by the ECU, which uses various pieces of information to send commands to the control motor that moves the swash plate arm. Some of the signals used to determine optimal output of the transmission include throttle opening, vehicle velocity, engine speed, motor swash plate angle, and gear position.

In the fully automatic modes (non-ESP), the ECU continuously monitors these signals. When a change in motor swash plate is deemed necessary, the ECU sends a signal to the control motor, which moves the ball screw (attached to the swash plate arm) via reduction gears. There are two rider-selectable automatic modes: the D1 mode emphasizes higher engine power output for riding performance; the D2 mode maximizes torque output performance. Within these modes, there is a choice of standard output ratios (drive) or lower output ratios (low) using a car-like shift lever. Reverse can also be selected using the gear lever, which engages a gear located in the subtransmission.

When the operator selects the ESP feature, "up" and "down" buttons on the handlebar switch are enabled. When the appropriate button is pressed, the ECU commands the control motor to move the swash plate to the next higher or lower preset position.

For more information, visit www.honda.com

Error 404--Not Found

Error 404--Not Found

From RFC 2068 Hypertext Transfer Protocol -- HTTP/1.1:

10.4.5 404 Not Found

The server has not found anything matching the Request-URI. No indication is given of whether the condition is temporary or permanent.

If the server does not wish to make this information available to the client, the status code 403 (Forbidden) can be used instead. The 410 (Gone) status code SHOULD be used if the server knows, through some internally configurable mechanism, that an old resource is permanently unavailable and has no forwarding address.