Other competitive solutions

Technology A: Hybrid pneumatic engine applied to a conventional engine

Technology B: Supercharged engine and derived hybrid propulsion system

Technology C: Hybrid transport system

Technology D: Variable compression ratio engine + piston deactivation

 

Technology A: Hybrid pneumatic engine applied to a conventional engine

 

The new proposed Hybrid Pneumatic Engine (fig. 1) is made in the simplest manner using a mechanical control of an air circuit existent between the combustion chamber and an air tank. This mechanical system offers the same main features as the other pneumatic solutions but with a cost reduced to a half.

Fig. 1

In this simplest manner, the air circuit existent between the four combustion chambers (in the case of four cylinders engine) and the air tank is controlled by the use of a single rotating valve acted by the camshaft and having same RPM. To make that are used two gears. The rotating valve has also the possibility to move axially, driven by an actuator. In the cylinder head and in the rotating valve there are some holes which can make the connection between the combustion chamber and an air common rail. The air common rail is connected with the air tank by a pipe. With this most simple configuration it can achieve the recovery of the braking energy. The different modes of operation are controlled by the actuator. If it decides to achieve also the “stop and start” operation in pneumatic mode, musts to add in the hub of the rotating valve gear a phaser (similar with that used to change the camshaft timing) controlled by an electrovalve (nut shown). If we want to achieve the exhaust gas heat recovery, an even more complex configuration must be added (not shown here), but the base components remain the same. 

The operation of the hybrid vehicle using the present concept can be described as in the fig. 2. 

Fig. 2

Analysing the dynamics, even the engine is not supercharged the behaviour is similar with a vehicle having mechanical boosting system: the answer in torque is very fast (fig. 3).

Fig. 3

Consequently, the accelerations are improved with around 20% (fig. 4).

Fig. 4

We evaluate the cost in two variant:

  • Pneumatic Hybrid Engine with braking recovery and stop & start = HE1
  • Pneumatic Hybrid Engine with braking recovery, stop & start and exhaust gas heat recovery = HE2

HE1 cost is around 400 €/vehicle and HE2 cost is around 700 €/vehicle.
In the figure 5 is indicated the comparison with other solutions, considering also the anticipated fuel economy.

Fig. 5

There are two patent pending applications describing this technology one of them being about the exhaust gas heat recovery. 

Technology B: Supercharged engine and derived hybrid propulsion system

Technology C: Hybrid transport system

Described by http://www.hybrid-engine-hope.com/hybrid_transport_system

 

For bus

For truck

Technology D: Variable compression ratio engine + piston deactivation