Integrative Gas Engine Control via Exhaust Temperature Feedback

The patent combines separate control functions for engine speed and air-fuel ratio into a single integrated control unit that simultaneously manages both parameters. This merging eliminates the need for multiple independent control devices, reducing overall system complexity while improving coordination between speed and mixture control through unified processing and decision-making logic.

The control unit is designed to perform multiple functions: it controls both engine speed and air-fuel ratio, adapts to different fuel types with varying calorific values, and adjusts operations across various engine loads. This multi-functionality allows a single device to replace multiple specialized controllers, reducing manufacturing costs while maintaining comprehensive control capability.

The patent introduces a correction mechanism that acts as an intermediary to compensate for the lack of direct oxygen sensor feedback. By measuring exhaust gas temperature and using it to calculate and correct the air-fuel ratio, the system achieves accurate mixture control without requiring expensive oxygen sensors, thereby maintaining measurement precision while reducing manufacturing costs.

The patent replaces the chemical sensing mechanism of oxygen sensors with a thermal measurement approach. By using exhaust gas temperature sensors and applying thermal principles to infer air-fuel ratio, the system substitutes expensive chemical sensors with more economical thermal sensing, achieving comparable control accuracy at lower cost.

The patent changes the control parameter from throttle opening area to fuel injection quantity and timing. Instead of restricting air flow through throttle valve opening, the system maintains relatively wide throttle opening to minimize pumping losses and controls engine speed by adjusting the amount and timing of fuel injection, thereby achieving speed control with reduced energy loss.

The patent inverts the conventional control approach: rather than controlling speed by restricting air intake through throttle valve, it controls speed by regulating fuel supply after the throttle. This inversion allows the throttle to remain open wider, reducing pumping losses, while fuel injection quantity and timing become the primary control variables for speed regulation.

The patent implements a feedback control mechanism where exhaust gas temperature is continuously monitored and used to correct air-fuel ratio calculations. When fuel gas flow is rapidly increased for load response, the system detects the resulting temperature changes and adjusts the air-fuel ratio accordingly, maintaining accuracy despite rapid fuel flow changes. This feedback loop ensures that rapid response does not compromise mixture precision.

The patent performs preliminary calculation of the correction amount based on exhaust gas temperature before finalizing the fuel injection quantity. By pre-calculating the necessary air-fuel ratio adjustment based on thermal conditions, the system can rapidly respond to load changes while ensuring the correct mixture is delivered, preventing both over-fueling and under-fueling during transient operations.