2) You are responsible for selecting automobiles that will be used in your companys fleet and have been asked to determine the energy consumption of the described vehicles for each of the processes described below. The vehicles have the following combined wind drag and rolling friction force during average operation conditions. The relationship for this force is

Ff = (0.0214m + 2.63)

where, m=vehicle mass and Ff is the combined wind and rolling friction forces in N.

One automobile is an all-wheel drive hybrid vehicle with a mass of 1450 Kg and it is powered by a storage battery- motor combination that provides electricity to four wheel mounted motors. The batteries in the hybrid configuration are charged using an internal combustion engineelectrical generator combination at the end of the driving cycle or by regenerative braking. The battery in this problem has sufficient energy storage to accomplish the driving cycle and it is used to keep account of the energy used in each driving process. For the purpose of this problem the battery is initially fully charged. Determine the change in the chemical energy of the battery for each described process. The efficiency of the battery charging process is 90% when it is charged from the engine. The efficiency of the regenerative braking mechanism is 85% and is defined as the energy provided to the battery divided by the braking energy needed to reduce the speed of the automobile. The battery charging process is included in the regenerative braking efficiency. The battery discharge efficiency is 90%. The battery efficiencies are defined as the energy provided by the battery divided by the change in the chemical energy of the battery during the discharge and the reciprocal of this parameter for the charging phase. The hybrid regeneration braking system can operate down to a velocity of 10 Km/hr when the standard friction brakes are applied. Neglect the internal energy of the vehicle and its systems in these calculations. The efficiency of the engine-generator system is 39%.

The second automobile has a mass of 1200 Kg, has the same all wheel motor drive configuration and is powered by a conventional internal combustion engine with a generator that has an efficiency of 41%. In this configuration there is no regenerative braking mechanism.

The different driving cycles are composed of the following individual activities.

a) The vehicle accelerates from a stop to a speed of 35 km/hr. This acceleration takes place in 18 seconds at a constant accelerate rate of 0.54 m/s2 .

b) The vehicle stops from a velocity of 35 km/hr at a constant deceleration rate of 0.59 m/s2 during regenerative braking and of 0.65 m/s2 during frictional braking.

c) A hill climb with an elevation change of 125 m at an angle of 9 degrees and a constant velocity of 35 km/hr.

d) Calculate the power from the battery required during the hill climb described in part (b).

e) A hill descent with an elevation change of 125 m at an angle of 12 degrees and a constant velocity of 35 km/hr. f) A level driving distance of 53 km.

2b) Determine the chemical energy change in the battery and the thermal energy (heat) added to the environment (heat flow) for a), b), d) and e) of the above components of the driving cycle.

2c) Using the above results consider two driving cycles that your company uses. The first is composed of 31 start and stops, 5 hill climbs and descents and a level, constant velocity component of 21 km. The second driving cycle is composed of two start stops, one hill climb and descent and 210 km of level, constant velocity driving.

Based on your calculations, write a recommendation for the vehicles to purchase. The company plans to purchase three vehicles, two will be used for the first driving cycle and the third for the second driving cycle. The heating value of gasoline is 46.5 MJ/Kg and its density is 0.77 Kg/L. The cost of gasoline is $0.60/L. The recommendation is to the Chief Financial Officer of the company who has a MBA and a public relations background.

ONLY NEED PART D 2B and 2C