Purification system

Abstract

OCR07AP [Problem] To achieve both improved exhaust gas purification rate and inhibition of ammonia emissions into the atmosphere, [Solution] The purification system includes an engine 1 catalytic converter 21 that reacts the absorbed ammonia with nitrogen oxides present in engine 1's exhaust gas to purify it; a motor 41 driven to compensate for the difference between a) engine load of engine 1 and b) drive load when the drive load of the drive device 5 driven by engine 1 changes; a battery 42 that powers motor 41; and a target setting so that the target absorption rate of the catalytic converter 21 increases as the remaining capacity of the battery 42 increases.

Claims

OCR07AP1.

1. A purification system comprising a catalytic converter that reacts absorbed ammonia with nitrogen oxides present in the engine exhaust gas to purify the exhaust gases; a motor that assists the engine; a battery that supplies power to the motor; and an injection controller that regulates the amount of urea injected, so that the amount of ammonia absorbed by the catalytic converter increases as the battery's residual capacity increases.

2. A purification system under claim 1, which is further integrated with a target setting section that increases the target value of the catalytic converter's absorption as the residual capacity increases, at which point the urea injection controller injects urea to bring the absorption to the target value.

3. A purification system under claim 2, where if the residual capacity is less than a certain capacity, the setting section sets the absorption to the target value, at which point the catalytic converter's exhaust gas purification rate is equal to or greater than the value at which nitrogen oxide emissions into the atmosphere are less than the emission reference value. 4.

5. A purification system under claim 2 or 3, where if the residual capacity is equal to or greater than the secondary capacity and the engine exhaust gas temperature is the catalytic activation temperature, the setting is set to the upper limit target value of the amount of ammonia that the catalytic converter can absorb.

6. A purification system under claim 1 to 5, which includes a drive controller that keeps the engine running in a steady state so that i) the engine exhaust gas temperature becomes equal to or greater than the catalytic activation temperature and ii) the engine load is constant.

8. One of the purification systems under Claim 2 through 5, which incorporates a urea injection section located in the exhaust pipe for exhaust gas venting and injecting urea into the exhaust pipe, where a catalytic converter is located at the end of the exhaust pipe urea injection section, and an injection controller that causes the urea injection section to inject urea into the exhaust pipe in an amount corresponding to the difference between a) the estimated amount of ammonia currently adsorbed to the catalytic converter and b) the target value set by the setting section.The purification system under Claim 8, where the injection regulator increases the amount of urea injected into the urea injection section when the difference between the estimated amount and the target value increases; if the estimated amount is less than the target value, the urea injection section does not inject urea into the exhaust pipe if the estimated amount is equal to or greater than the target value;

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