Gear System Description - Electronic Control System

For locations of each component on the vehicle, refer to Component Location Index.

Functional Diagram

The electronic control system consists of the PCM, sensors, switches, and shift solenoid valves. The PCM receives input signals from the sensors, switches, and other control units, processes data, and outputs signals for the engine control system and the gear control system. The gear control system includes clutch pressure control. The PCM determines the drive mode based on the information sent from each sensor and control unit. The PCM actuates shift solenoid valves A and B to engage over drive clutch.

Courtesy of HONDA, U.S.A., INC.

Clutch Pressure Control

The PCM actuates shift solenoid valves A and B to control the over drive clutch pressure. The PCM receives input signals from the various sensors, switches, and control units, then processes the data, and determines the drive mode. When the drive mode is shifted from HV drive mode to engine drive mode, the PCM actuates shift solenoid valve B and makes the over drive clutch ready to be engaged. To reduce the shock caused during the engagement, the PCM controls the rpm of the engine and traction motor to be synchronized with each other before engaging the over drive clutch. Once speed of the engine and traction motor are synchronized, the PCM actuates shift solenoid valve A, and engages the over drive clutch. When the drive mode is shifted from engine drive mode to HV drive mode, the PCM turns off shift solenoid valves A and B, and releases the over drive clutch.

Courtesy of HONDA, U.S.A., INC.

Deceleration Selector

Deceleration selector is designed to use an auxiliary brake for engine braking, and produces decelerating power by the regenerative braking system and the coordination of the electric servo brake system. The PCM controls decelerating power while driving in D position/mode without pressing the accelerator by comparing actual driving conditions with programmed driving conditions. The PCM monitors driver input from the paddle shifters, the SBW shifter control module, the motor control module, the battery condition monitor module, the electric servo brake control unit, and others.

Courtesy of HONDA, U.S.A., INC.

The vehicle can decelerate by pressing the paddle shifter -, and the decelerating stage returns by pressing the paddle shifter +. There are four stages of the decelerating power in the system, the driver can select the stage by using the paddle shifters. Each time the paddle shifter is pressed, the deceleration selector indicator in the gauge control module displays the current stage.

There are limits to use the deceleration selector under certain conditions. When the deceleration selector makes an unavailable stage of the decelerating power, the PCM commands to change to next lower stage, or to cancel decelerating. If an unavailable stage is selected by pressing the paddle shifter -, the vehicle will not change the stage, and the deceleration selector indicator blinks the arrow (s) of the selected stage several times, then returns to the current stage.

Decelerating Limitations

When high voltage battery is full-charged.
When high voltage battery temperature is too low.
When high voltage battery temperature is too high.
When the protection of the hybrid system is required.
The vehicle is coasting at speeds out of the allowable speed when pressing the paddle shifter.
When the vehicle is stopped while turning on the ACC with Low Speed Follow (LSF).

Each stage of the decelerating power, which can be selected by the deceleration selector, is set in accordance with the vehicle speed.

Courtesy of HONDA, U.S.A., INC.

When the deceleration selector is selected, the system sets the decelerating power to:

The 1st stage, when the system determines the vehicle is driving on a flat road.
The 3rd stage, when the system determines the vehicle is descending a steep hill, and the 2nd and 1st stages are available.