Engineering patents usually present an perception into the way forward for the car, and if Nissan’s newest is something to go by, the Japanese model might need discovered a strategy to squeeze a little bit additional life out of the combustion engine, particularly when utilized in a hybrid configuration. In a brand new patent found by DrivingOnRoad filed with the Japan Patent Workplace (JPO), Nissan particulars a brand new variable valve timing mechanism to be used in a collection hybrid system. That is the kind of system utilized in Nissan’s e-Energy hybrid automobiles, just like the forthcoming Rogue e-Energy that may arrive within the US subsequent 12 months.
The brand new design particularly works with a VVT system on the exhaust cam, and will scale back car emissions even additional, extending the lifespan of the combustion engine in an period of ever-tightening emissions laws.
Specialised Exhaust Cam VVT Addresses EGR Points With Frequent Engine Deactivation
E-Energy, in case you are not acquainted, depends on the combustion engine as a generator, powering electrical motors as a substitute of driving the wheels straight. However which means, relying on the facility necessities and sort of driving you are doing, the combustion engine itself is not all the time operating. The issue the patent addresses is that when the engine recurrently stops and begins, a daily exhaust fuel recirculation (EGR) system resets its valve to closed when the engine switches off. When the engine begins once more, there is a second on restart when the engine is pushing gasoline that hasn’t been burned via the system straight via the exhaust slightly than recirculating a portion of exhaust fuel again into the consumption to burn off any petrol that did not combust the primary time spherical. That is dangerous information for emissions testing.
Basically, the patented system all the time restarts with the EGR system recirculating on account of valve overlap with the engine’s variable valve timing (VVT) system. When the engine is operating and the oil stress is up throughout the VVT actuator, the VVT system maximizes retardation on the exhaust timing, creating most permissible overlap between exhaust and consumption valve timing. However Nissan’s patent describes a locking pin mechanism, which engages the second the engine is switched off, holding the exhaust timing on this place with out the necessity for oil stress to take action.
This forces most EGR on start-up, notably when the engine is chilly, and achieves the last word aim: as full a burn as attainable when chilly and heating the catalytic converters faster to cut back hydrocarbon emissions within the moments submit start-up.
Secondary Advantages Are Significant Too
Whereas decreasing hydrocarbon emissions seems to be the principle aim, there are different advantages. The mechanical load on oil pumps is decreased at startup, as they not have to pump oil via the VVT system, solely via the common channels throughout the engine itself. Longer-lasting oil pumps are good for engine life, and never needing to unfold engine oil round as a lot when the motor is chilly means the oil pumps can push the oil to the place it is wanted probably the most.
However Nissan additionally suggests this VVT system might be utilized to the consumption facet of the valvetrain, which might have a completely completely different impact: smoother restarts.
Some of the widespread complaints about hybrid automobiles is the jerkiness of the engine restarting. In a parallel hybrid system, the jerk can usually disrupt the smoothness of your drive, whereas in a collection hybrid system like e-Energy, it creates harsh vibrations and noise that may be perceived as disagreeable. However when VVT is utilized to the consumption facet, it will probably decompress the combustion chamber throughout engine cranking. This ends in smoother, faster engine ignition. The impact is much more pronounced when the automotive is generally appearing as an electrical automotive, with longer intervals between the engine operating and being silent and vibration-free.
Not Simply Restricted To Sequence Hybrid Programs
The patent is explicitly for a collection parallel hybrid system, however in concept, the locking pin mechanism and advancing/retarding valve timing know-how might be utilized to a daily parallel hybrid system the place the engine drives the automotive in addition to the electrical motors. It could produce the identical advantages – extra environment friendly exhaust fuel recirculation and smoother engine restarts. So how does this lengthen the lifespan of combustion, you ask?
Nicely, sometimes, at start-up is when engines are likely to emit probably the most hydrocarbons for the least quantity of achieve. Chilly beginning means the engine is not in its most effective working window, heat-wise, and because the ECU tries to quickly heat the catalytic converters, it is pushing a richer air-fuel combination into the combustion chamber, a lot of which is being dumped into the exhaust incompletely burned.
As we shift from the vast majority of automobiles on the street being inside combustion solely to hybrid, refining the methods for each gasoline effectivity and emissions might be essential. If Nissan could make the combustion engine as environment friendly as attainable in a hybrid system, it will scale back the stress from numerous governments globally to do away with the combustion engine altogether. And if governments cease pushing for the tip of combustion, it will imply there’s extra hope for these of us who wish to take heed to an engine in motion as a substitute of the whirring of electrical motors.
Patent filings don’t assure the usage of such know-how in future automobiles and are sometimes used solely as a method of defending mental property. Such a submitting can’t be construed as affirmation of manufacturing intent.
Supply: JPO