Vehicle Cruise Control ECU Throttle Actuator Speed Limiting
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Solution Overview
Problem
Existing engine control methods for recreational vehicles, such as ATVs and personal watercraft, face challenges in maintaining consistent performance across varying loads and speeds, leading to rough engine operation and inefficient speed control, especially when equipped with throttle-by-wire systems.
Innovation Solution
A vehicle control system that includes an electronic control unit (ECU) capable of switching between normal and cruise control modes, using throttle position and vehicle speed sensors to adjust the throttle valve actuator, ensuring consistent vehicle speed and performance by limiting engine power based on predetermined settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the ECU limits engine power by controlling ignition and fuel injection when maximum speed is reached, then the maximum speed is limited, but the engine operation becomes rough
Solution Approach 1:
The system performs preliminary action by closing the throttle valve before the engine reaches maximum speed. When the ECU detects that the engine speed is approaching the predetermined maximum, it proactively reduces the throttle valve opening degree through the throttle valve actuator, preventing the need for abrupt ignition/fuel injection cuts that cause rough operation. This anticipatory throttle control maintains smooth engine operation while achieving speed limitation.
2Speed
If the predetermined maximum engine speed is selected to ensure the personal watercraft will not exceed 105 km/h under light load, then the speed limit is met, but the performance is reduced when load is increased
Solution Approach 1:
The system implements dynamic speed control by continuously monitoring both engine speed and vehicle speed, and by adjusting the throttle valve opening degree dynamically based on real-time conditions. Rather than using a fixed engine speed limit, the ECU modulates the throttle valve to maintain the vehicle speed below 105 km/h while allowing the engine to operate at higher speeds when needed for performance, thus adapting to varying load conditions and terrain requirements.
3Speed
If the ECU controls the throttle valve based on engine speed to limit maximum speed, then speed control is improved, but the system complexity increases
Solution Approach 1:
The system achieves multi-functionality by using the existing throttle valve actuator and ECU for both normal throttle control and speed limiting functions. The same hardware components are utilized to perform multiple tasks: the throttle valve actuator serves both for driver-controlled acceleration and for ECU-enforced speed limiting, while the ECU integrates both engine management and speed control algorithms. This eliminates the need for separate dedicated speed control hardware, reducing overall system complexity.
Data Source
AI summary
A vehicle having a vehicle body, a seat, an engine, a throttle body, a throttle valve, a throttle valve actuator, a throttle operator, a throttle operator position sensor, a cruise control switch, and a vehicle speed sensor. An ECU controls operation of the engine in one of a normal operation mode and a cruise control operation mode. When in the normal operation mode, the ECU sends a first control signal to the throttle valve actuator based on the throttle operator position signal. When the cruise control switch engages the cruise control operation mode, the ECU sends a second control signal to the throttle valve actuator based on the vehicle speed signal such that the vehicle speed is maintained at a vehicle cruising speed. The ECU returns to the normal operation mode when the throttle operator position becomes less than or equal to a reference throttle operator position.