Not able to install ruby 2.2.4

I using image of Ubuntu Ruby on Rails 14.04. I am using user rails, which is already in image. I have added user as sudoer. I am trying to install ruby 2.2.4 using rvm but it is not working. It is showing that

rvm install 2.2.4

Warning, new version of rvm available '1.27.0', you are using older version '1.26.11'.
You can disable this warning with:    echo rvm_autoupdate_flag=0 >> ~/.rvmrc
You can enable  auto-update  with:    echo rvm_autoupdate_flag=2 >> ~/.rvmrc
Searching for binary rubies, this might take some time.
Found remote file https://rubies.travis-ci.org/ubuntu/14.04/x86_64/ruby-2.2.4.tar.bz2
Checking requirements for ubuntu.
Requirements installation successful.
ruby-2.2.4 - #configure
ruby-2.2.4 - #download
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
Warning: Failed to create the file bin-ruby-2.2.4.tar.bz2.part: Permission 
Warning: denied
  0 22.9M    0 16384    0     0  31495      0  0:12:45 --:--:--  0:12:45 31495
curl: (23) Failed writing body (0 != 16384)
There was an error(23).
Checking fallback: ftp://rubies.travis-ci.org/ubuntu/14.04/x86_64/ruby-2.2.4.tar.bz2?rvm=1.26.11
Checking fallback: http://www.mirrorservice.org/sites/rubies.travis-ci.org/ubuntu/14.04/x86_64/ruby-2.2.4.tar.bz2?rvm=1.26.11
No fallback URL could be found, try increasing timeout with:

    echo "export rvm_max_time_flag=20" >> ~/.rvmrc

Downloading https://rubies.travis-ci.org/ubuntu/14.04/x86_64/ruby-2.2.4.tar.bz2 failed.
Mounting remote ruby failed with status 2, trying to compile.
Checking requirements for ubuntu.
Requirements installation successful.
Installing Ruby from source to: /usr/local/rvm/rubies/ruby-2.2.4, this may take a while depending on your cpu(s)...
ruby-2.2.4 - #downloading ruby-2.2.4, this may take a while depending on your connection...
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0Warning: Failed to create the file ruby-2.2.4.tar.bz2.part: Permission denied
  0 12.7M    0 13032    0     0  25261      0  0:08:47 --:--:--  0:08:47 25304
curl: (23) Failed writing body (0 != 13032)
There was an error(23).
Checking fallback: http://ftp.ruby-lang.org/pub/ruby/2.2/ruby-2.2.4.tar.bz2
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0Warning: Failed to create the file ruby-2.2.4.tar.bz2.part: Permission denied
  0 12.7M    0  1167    0     0   1271      0  2:54:52 --:--:--  2:54:52  1271
curl: (23) Failed writing body (0 != 1167)
There was an error(23).
Failed download
There has been an error fetching the ruby interpreter. Halting the installation
```.

When using rvmsudo then

rvmsudo rvm install 2.2.4
sudo: rvm: command not found