BMW Files Patent for Split Engine Hybrid

Rumors | January 10th, 2010 by 4
bmw hybrid patent

The rumormill is back in business and the British magazine Autocar speculates reports that BMW is working on an hybrid system that uses two engines. …

The rumormill is back in business and the British magazine Autocar speculates reports that BMW is working on an hybrid system that uses two engines. According to the UK fellas, a patent has been filed by BMW which describes the technology as a “hybrid vehicle having a split engine”. The hybrid setup comprises a first internal combustion engine unit and a second internal combustion engine unit, and the idea behind this technology is for the car to be driven by one of the engines and the electric motor at low speeds or when power demands are low. When more speed or power is needed, the second engine cuts in.

The patent does not disclose any number or specific details, but it does mentions the possibility of two-cylinder engines being employed. To confuse us even further, the patent mentions that the two engines could differ in size, for example a four-cylinder unit coupled with a two-cylinder powerplant.

The electric motor will assist the two engines to generate extra torque compensating for any loss when the system switches between the two.

bmw hybrid patent 655x409

The currently launched BMW ActiveHybrid X6 features a two-mode hybrid system which allows the X6 to run either on its electric motors alone at low speeds, internal combustion or a combination of both. X6 Hybrid makes use of not one, but two electric motors which deliver 91 hp and 86 hp, respectively, with peak torque values of 192 lb-ft and 206 lb-ft. Top speed in the electric mode is 37 mph, maximum range is 1.6 miles.

On the other hand, the ActiveHybrid 7 uses a different electric drive setup from the X6 Hybrid and it’s being considered a mild hybrid. The system was developed in collaboration with Mercedes Benz. The upgraded V8 twin-turbo with High Precision Direct Injection runs together, at the same time, with a 3-phase synchronous electric motor which is positioned between the engine and the torque converter. The electric motor generates approximately 20 hp and peak torque of 155 lb-ft.

The future looks bright for BMW and clearly, Project i program is well underway and we expect more hybrid powered BMWs in the next few years, beginning with the BMW 5 Series Hybrid model.

4 responses to “BMW Files Patent for Split Engine Hybrid”

  1. Doug says:

    Any idea what 8a, A2 and 7a are? It must be some kind of coupling or clutch.

    Presumably motor 1 is the one that shuts down, and presumbly goes to 0 rpm while motor 2 is still running at variable rpm. What has to happen to motor 2 in order to start motor 1? Does a clutch engage and synchronize their speeds? Or, does m2 run at a higher speed (eg, viscous coupling).

  2. X5 SoB says:

    This is a cool idea, you could basically cut a 3.0 liter 2/3 & 1/3, with an electric motor as an interface to smooth power delivery. The motor could spool up the 2.0 liter engine when extra power is needed, and augment the 1.0 liter engine for medium power needs.
    I’m curious though, wouldn’t cylinder deactivation accomplish the same thing, albeit with some parasitic losses?

Leave a Reply

Your email address will not be published. Required fields are marked *